Conversion of polyolefins

Abstract

Disclosed herein, inter alia, are methods of converting polyethylene to propylene and a C3 to C30 alkene, and methods of converting polypropylene to a mixture of propylene and isobutylene and a C3 to C30 alkene with high yield and lower reaction temperature.

Description

PATENT Attorney Docket No.: 052103-531001WO CONVERSION OF POLYOLEFINS CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 668,074,filed July 5, 2024, which is incorporated herein by reference in its entirety and for all purposes. STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0002] This invention was made with government support under grant no. DE-AC02-05CH11231 awarded by the Department of Energy. The government has certain rights in the invention. BACKGROUND

[0003] The accumulation of plastic waste in landfills and the environment is a massiveeconomic and environmental issue that is expected to intensify in the coming decades (1). Aliphatic polyolefins, almost entirely composed of polyethylene (PE) and polypropylene (PP), account for the majority (57%) of all polymer resins produced (2). These aliphatic polyolefins contain C–H and C–C bonds which are inert to almost all chemical transformations. Accordingly, aliphatic polyolefins are among the longest-lived waste plastics in the environment (3) and the least amenable to valorization by chemical modification.

[0004] Thermal pyrolysis of polyethylene and polypropylene at ≥500 °C or catalyticthermolysis can convert these polyolefins to a complex mixture of hydrocarbons (4, 5) withvarying levels of selectivity for olefin (6) or arene (7) products, and many systems for chain cleavage with hydrogen (hydrogenolysis) catalyzed by transition-metals have been reported to convert PE and PP to mixtures of linear and branched alkanes (8-11). Tandem reactions have also been reported to cleave polyolefins. In one case, net alkane metathesis that combines PE with an excess of light alkanes yields mixtures of short alkanes via tandem alkane dehydrogenation and olefin metathesis (12-14), and tandem dehydrogenation, aromatization, and hydrogenolysis has been reported to convert polyethylene into mixtures of alkylarenes (15, 16). Pyrolysis andPATENT Attorney Docket No.: 052103-531001WO hydrogenolysis often also produce substantial quantities of methane, contributing to greenhouse gas emissions.

[0005] The existing methods of selective conversion of polyethylene, polypropylene, andtheir mixtures suffer from low selectivity, produce large quantities of greenhouse gases, or rely on expensive, single-use catalysts. The isomerizing ethenolysis of unsaturated polyolefins could be an energetically and environmentally viable route to propylene and isobutylene, but require noble-metal homogeneous catalysts and an unsaturated polyolefin, and the process has been limited to polyethylene. Methods are thus required that generate easily separable products with high selectivity, without producing methane. In addition, the massive scale of polyolefin waste (>160 megatons in 2015) makes methods that selectively generate products with a similarly large demand an urgent need (2). BRIEF SUMMARY

[0006] In an aspect, provided is a a method of converting a polyethylene to propylene, themethod comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the propylene. In an aspect, provided is a a method of converting a polyethylene to propylene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the propylene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support or oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0007] In an aspect is provided a method of converting a polypropylene to propylene andisobutylene, the method comprising contacting the polypropylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the propylene and the isobutylene. In an aspect is provided a method of converting a polypropylene to propylene and isobutylene, the method comprising contacting the polypropylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the propylene and the isobutylene, wherein the olefin metathesis catalyst comprises a transition metal attached to aPATENT Attorney Docket No.: 052103-531001WO metal oxide solid support or oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin smerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0008] In an aspect is provided a method of converting a mixture of polyethylene andpolypropylene to a mixture of propylene and isobutylene, the method comprising contacting the polyethylene and polypropylene mixture with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the mixture of propylene and isobutylene. In an aspect is provided a method of converting a mixture of polyethylene and polypropylene to a mixture of propylene and isobutylene, the method comprising contacting the polyethylene and polypropylene mixture with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the mixture of propylene and isobutylene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0009] In an aspect is provided a method of converting a polyethylene to a C3 to C30 alkene,the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene. In an aspect is provided a method of converting a polyethylene to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide or oxide solid support solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0010] In an aspect is provided a method of converting a polyethylene, a polypropylene, or amixture of the two to a C3 to C30 alkene, the method comprising contacting the polyethylenePATENT Attorney Docket No.: 052103-531001WO with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene. In an aspect is provided a method of converting a polyethylene, a polypropylene, or a mixture of the two to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIGS. 1A-1C. FIG. 1A shows prior work utilizing a strategy of dehydrogenation andtandem isomerizing ethenolysis to effect the conversion of polyethylene to propylene. FIG.1B demonstrates previous work on the application of thermal and catalytic pyrolysis for the chemical recycling of polyolefins, limited to PE. FIG.1C shows current work on the combination of catalytic cracking and isomerizing ethenolysis to yield light olefins from PE and PP.

[0013] FIGS. 2A-2D demonstrate experiments on the pyrolysis and isomerizing ethenolysisof polyolefins. FIG.2A shows amount of olefin in PE and PP chains after chain cleavage at 320 °C in the presence of ethylene (10 bar) with and without Na / γ-Al2O3 and WO3 / SiO2, determined by 1H NMR spectroscopy. FIG.2B sows normalized distributions of the molecular weights of PE and PP chains after chain cleavage at 320 °C in the presence of ethylene (10 bar) with and without Na / γ-Al2O3, determined by High Temperature Size Exclusion Chromatography (HT- SEC). FIG.2C shows yields of PIE on various examples of commercial and waste plastic: PE (1.00 g, 35.7 mmol of monomer units) or PP (1.00 g, 23.8 mmol of monomer units), WO3 / SiO2(400 mg, 0.108 mmol W), and Na / γ-Al2O3 (400 mg, 1.74 mmol Na) heated to 320 °C under 15.0 bar of ethylene (175 mmol) for 90 min. FIG.2D demonstrates photographs of sources of waste subjected to PIE: waste HDPE from a gallonjug, waste PP from a centrifuge tube, and waste LDPE from a bread bag.PATENT Attorney Docket No.: 052103-531001WO

[0014] FIGS. 3A-3D. FIG. 3A shows isotopic labeling experiments with PE 13C2 and PP(1-13C). FIG.3B shows investigation of catalyst recyclability. FIG.3C demonstrates investigation of the effect of pressure on the yield of HDPE PIE in a semi-batch reactor setup. FIG.3D shows solated yield of a 3.6 : 1 mixture of liquified propylene and butenes from the PIE of 50 g of HDPE.

[0015] FIG. 4 shows N2 adsorption isotherms for catalysts and supports.

[0016] FIG. 5 shows calibration curves for quantification of W by ICP-OES.

[0017] FIG. 6 depicts 1H NMR spectrum of polyethylene heated at 320 oC for 90 minutesunder ethylene (15 bar) in the absence of Na / Al2O3 catalyst.

[0018] FIG. 7 depicts 1H NMR spectrum of PP heated at 320 oC for 90 minutes underethylene (15 bar) in the absence of Na / γ-Al2O3.

[0019] FIG. 8. depicts 1H NMR spectrum of HDPE exposed to Na / Al2O3 under ethylene (15bar) at 320oC for 90 minutes.

[0020] FIG. 9 depicts 1H NMR spectrum of PP exposed to Na / γ-Al2O3 at 320 oC underethylene (15 bar) for 90 minutes.

[0021] FIG. 10 depicts 1H NMR spectrum of PP exposed to WO3 / SiO2 at 320 oC underethylene (15 bar) for 90 minutes.

[0022] FIG. 11 depicts 1H NMR spectrum of waste HDPE acquired from a1.0 galon jug.

[0023] FIG. 12 depicts 1H NMR spectrum of waste PP acquired from a centrifuge tube.

[0024] FIG. 13 depicts 1H NMR spectrum of waste LDPE acquired from a bread bag.

[0025] FIG. 14 depicts 1H NMR spectrum of LDPE acquired from a bread bag, withresonance corresponding to 1,3,5-trimethoxybenzene internal standard at δ 6.16 and 3.82 ppm, integrated against the methylene units of polyethylene at 1.35 ppm.

[0026] FIG. 15 shows HT-SEC chromatograms of examples of waste plastics.

[0027] FIG. 16 shows the photograph of the reactor assembly for the large-scale PIE ofHDPE.PATENT Attorney Docket No.: 052103-531001WO

[0028] FIG. 17 shows the photograph of the modified impeller assembly used for the large-scale PIE of HDPE.

[0029] FIG. 18 depicts 1H NMR spectrum of the oil fraction collected at 20 oC from thelarge scale PIE of HDPE.

[0030] FIG. 19 depicts yields of propylene from the isomerizing ethenolysis of HDPE withWO3 / SiO2 and Fe / Al2O3.

[0031] FIG. 20 depicts yields of propylene from the isomerizing ethenolysis of HDPE withWO3 / SiO2and Na2CO3-Fe / Al2O3.

[0032] FIG. 21 depicts yields of propylene from the isomerizing ethenolysis of HDPE withthe Na-Fe / Al2O3catalyst mixture after its regeneration with dimethyl ether. DETAILED DESCRIPTION I. Definitions

[0033] The abbreviations used herein have their conventional meaning within the chemicalarts.

[0034] The term “polyethylene” “ is used in accordance with its plain ordinary meaning inthe art, and refers to a class of organic polymers prepared by polymerization of ethylene.

[0035] The term “high-density polyethylene” or “HDPE” is used in accordance with its plainand ordinary meaning and refers to a thermoplastic polyethylene. In embodiments, the density of HDPE ranges from about 0.93 g / cm3to about 0.97 g / cm3. HDPE has minimal branching of its polymer chains and is therefore denser than low-density polyethylene.

[0036] The term “low-density polyethylene” or “LDPE” is used in accordance with its plainand ordinary meaning and refers to a thermoplastic polyethylene of higher density than HDPE. In embodiments, the density of LDPE ranges from about 0.91 g / cm3to about 0.93 g / cm3.

[0037] The term “linear low-density polyethylene” or “LLDPE” is used in accordance withits plain and ordinary meaning and refers to a substantially linear polyethylene with significant numbers of short branches. LLDPE is typically a copolymer of ethylene and an alpha-olefin andPATENT Attorney Docket No.: 052103-531001WO differs from LDPE because of the absence of long chain branching. Typically, the density of LLDPE ranges from about 0.91 g / cm3to about 0.94 g / cm3.

[0038] The term “polypropylene” “ is used in accordance with its plain ordinary meaning inthe art and refers to a class of organic polymers prepared by polymerization of propylene.

[0039] The term “polyisobutene” or “PIB” is used in accordance with its plain ordinarymeaning in the art and refers to a class of organic polymers prepared by polymerization of isobutene.

[0040] The term “polymer” is used in accordance with its plain ordinary meaning in the artand refers to a molecule including repeating subunits (e.g., polymerized monomers).

[0041] The term “cross-linked polymer” is used in accordance with its plain ordinarymeaning in the art, and refers to polymer wherein a first polymer chain is connected to a second polymer chain via a linker.

[0042] The term “olefin metathesis” is used in accordance with its plain ordinary meaning inthe art and refers to an organic reaction that entails the redistribution of fragments of alkenes (olefins) by the scission and regeneration of carbon-carbon double bonds.

[0043] The term “olefin isomerization” is used in accordance with its plain ordinary meaningin the art and refers to a chemical process by which a compound with a carbon-carbon double bond is transformed into any of its isomeric forms, i.e., forms with the same chemical composition but with different structure or configuration and generally with different physical and chemical properties.

[0044] The term “catalyst” is used in accordance with its plain ordinary meaning in the artand refers to a species that increases the rate of a chemical reaction. The catalyst is not consumed in the reaction and can continue to act repeatedly.

[0045] The term “catalyst component(s)” is used in accordance with its plain ordinarymeaning in the art and refers to any substance which increases the rate of a specific chemical reaction. The term “catalyst composition” is used in accordance with its plain ordinary meaning in the art and refers to solid particulate comprising at least one catalyst component. A catalyst composition can include at least one catalyst component, at least two catalyst components, or atPATENT Attorney Docket No.: 052103-531001WO least three catalyst components. The catalyst composition can further comprise a catalyst support material. Catalyst components and the catalyst compositions made with the catalyst components described herein may be utilized to promote various reactions, such as, but not limited to, dehydrogenation, metathesis, isomerization, or combinations thereof.

[0046] The term “an olefin metathesis catalyst” is used in accordance with its plain ordinarymeaning in the art and refers to a transition metal complex that facilitates metathesis.

[0047] The term “olefin isomerization catalyst” is used in accordance with its plain ordinarymeaning in the art and refers to a catalyst that facilitates olefin isomerization. The term “homogenous olefin isomerization catalyst” is used accoridng to its plain and ordinary meaning in the art and refers to an olefin isomerization catalyst with an soluble component. The term “heterogenous olefin isomerization catalyst” is used accoridng to its plain and ordinary meaning in the art and an olefin isomerization catalyst with an insoluble component.

[0048] The term “basic olefin isomerization catalyst” is used in accordance with its plainordinary meaning in the art and refers to an olefin isomerization catalyst with a basic component.

[0049] The term “acidic olefin isomerization catalyst” is used in accordance with its plainordinary meaning in the art and refers to an olefin isomerization catalyst with an acidic component.

[0050] The term “a transition metal olefin isomerization catalyst” is used in accordance withits plain ordinary meaning in the art and refers to an olefin isomerization catalyst with a transition metal component.

[0051] The term “dehydrogenation step” is used in accordance with its plain ordinarymeaning in the art and refers to a chemical reaction by which hydrogen atoms are removed from an organic compound to form a new compound, e.g., to convert a saturated compound into an unsaturated compound.

[0052] The term “metal catalyst” is used in accordance with its plain and ordinary meaningand refers to a catalyst including a metal such as a transition metal or main group metal.

[0053] The term “solid support” for a catalyst is used in accordance with its plain andordinary meaning and refers to a solid material with a surface area that may act as a platform to,PATENT Attorney Docket No.: 052103-531001WO for example, immobilize and disperse the catalytic material, thus enhancing its activity and stability in a chemical reaction.

[0054] The term “metal oxide solid support” is a solid support with a metal oxid component.

[0055] The term “residence time” is used in accordance with its plain and ordinary meaningand refers to the time (e.g., an average time) that a reactant molecule spends in a reactor before it is converted into a product or is removed by a side reaction.

[0056] The term “about” means a range of values including the specified value, which aperson of ordinary skill in the art would consider reasonably similar to the specified value. In embodiments, about means within a standard deviation using measurements generally acceptable in the art. In embodiments, about means a range extending to + / - 10% of the specified value. In embodiments, about includes the specified value.

[0057] The term “contacting” is used in accordance with its plain ordinary meaning andrefers to the process of allowing at least two distinct species (e.g., chemical compounds including biomolecules or cells) to become sufficiently proximal to react, interact or physically touch. It should be appreciated; however, the resulting reaction product can be produced directly from a reaction between the added reagents or from an intermediate from one or more of the added reagents that can be produced in the reaction mixture.

[0058] The terms “comprises,” “comprising,” “containing” and “having” and the like canhave the meaning ascribed to them in U.S. Patent law and can mean “ includes,” “including,” and the like. “Consisting essentially of” or “consists essentially” likewise has the meaning ascribed in U.S. Patent law and the term is open-ended, allowing for the presence of more than that which is recited so long as basic or novel characteristics of that which is recited is not changed by the presence of more than that which is recited, but excludes prior art embodiments. II. Methods of Conversion of Polyethylene and Polypropylene

[0059] In an aspect, provided is a method of converting a polyethylene to propylene, themethod comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the propylene. In another aspect, provided is a method of converting a polyethylene to propylene, the method comprising contacting thePATENT Attorney Docket No.: 052103-531001WO polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the propylene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support or oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0060] In an aspect is provided a method of converting polypropylene to propylene and anisobutylene, the method comprising contacting the polypropylene with ethylene,an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the propylene and the isobutylene. In another aspect is provided a method of converting polypropylene to propylene and an isobutylene, the method comprising contacting the polypropylene with ethylene,an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the propylene and the isobutylene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support or oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0061] In an aspect is provided a method of converting a mixture of polyethylene andpolypropylene to a mixture of propylene and isobutylene, the method comprising contacting the polyethylene and polypropylene mixture with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the mixture of propylene and isobutylene. In an aspect is provided a method of converting a mixture of polyethylene and polypropylene to a mixture of propylene and isobutylene, the method comprising contacting the polyethylene and polypropylene mixture with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the mixture of propylene and isobutylene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.PATENT Attorney Docket No.: 052103-531001WO

[0062] In an aspect is provided a method of converting a polyethylene to a C3 to C30 alkene,the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene. In another aspect is provided a method of converting a polyethylene to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst, and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support or oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0063] In an aspect is provided a method of converting a polyethylene, a polypropylene, or amixture of the two to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene. In an aspect is provided a method of converting a polyethylene, a polypropylene, or a mixture of the two to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene, wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst. In embodiments, either of the olefin metathesis catalyst and / or the olefin isomerization catalyst catalyzes cracking of the polyolefin.

[0064] In the method of generation of higher olefins, catalytic cracking, cross-metathesiswith ethylene and olefin izomerization may act on polyethylene simultaneously. The higher olefins generated from this process may be a mixture of linear internal and terminal olefins with a carbon number ranging from C5-C15. These olefins may be generated by a process including a step of continuously flowing ethylene through the reactor (e.g. at 20 bar with a volumetric flow rate of 1000 SCCM). In embodiments, the gaseous outflow is cooled (e.g. to 20 °C) and the condensate is collected. The distribution of products generated by this process may be modified by adjusting the volumetric flow rate of ethylene, reactor volume, the reactor residence time (i.e.PATENT Attorney Docket No.: 052103-531001WO the amount of time it takes for the headspace of the reactor to be replaced, or the reactor volume divided by the volumetric flow rate), and / or the temperature of the outflowing gas.

[0065] In embodiments, in the method of generation of higher olefins the contact time withan olefin metathesis catalyst and an olefin isomerization catalyst is shorter leading to partial conversion.

[0066] The olefin metathesis catalyst and the olefin isomerization catalyst are as describedherein, including in embodiments.

[0067] In embodiments, a method of converting polypropylene to a mixture of propylene andisobutylene provides a mixture which is less than 6:1 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 5:1 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 4:1 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 3:1 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 2:1 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is 1:1 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 1:2 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 1:3 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 1:4 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 1:5 propylene to isobutylene. In embodiments, a method of converting polypropylene to a mixture of propylene and isobutylene provides the mixture which is less than 1:6 propylene to isobutylene.

[0068] In embodiments, the method of converting polyethylene to propylene describedherein requires no prior dehydrogenation step. In embodiments, the method of convertingPATENT Attorney Docket No.: 052103-531001WO polypropylene to a mixture of propylene and isobutylene described herein requires no prior dehydrogenation step. In embodiments, the method of converting polyethylene to a C3 to C30 alkene described herein requires no prior dehydrogenation step.

[0069] In embodiments, the method of converting polypropylene to a mixture of propyleneand isobutylene provides the yield of isobutylene of greater than 90%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 80%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 75%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 70%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 65%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 60%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 55%. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene provides the yield of isobutylene of greater than 50%.

[0070] In embodiments, the method of converting polyethylene to propylene is performed atabout 150oC to about 550oC. In embodiments, the method of converting polyethylene to propylene is performed at about 200oC to about 500oC. In embodiments, the method of converting polyethylene to propylene is performed at about 250oC to about 450oC. In embodiments, the method of converting polyethylene to propylene is performed at about 300oC to about 400oC. In embodiments, the method of converting polyethylene to propylene is performed at about 300oC to about 350oC.

[0071] In embodiments, the method of converting polyethylene to propylene is performed atabout 250oC. In embodiments, the method of converting polyethylene to propylene is performed at about 260oC.In embodiments, the method of converting polyethylene to propylene is performed at about 270oC. In embodiments, the method of converting polyethylene to propylene is performed at about 280oC. In embodiments, the method of converting polyethylene toPATENT Attorney Docket No.: 052103-531001WO propylene is performed at about 290oC. In embodiments, the method of converting polyethylene to propylene is performed at about 300oC. In embodiments, the method of converting polyethylene to propylene is performed at about 310oC. In embodiments, the method of converting polyethylene to propylene is performed at about 320oC. In embodiments, the method of converting polyethylene to propylene is performed at about 330oC. In embodiments, the method of converting polyethylene to propylene is performed at about 340oC. In embodiments, the method of converting polyethylene to propylene is performed at about 350oC. In embodiments, the method of converting polyethylene to propylene is performed at about 360oC. In embodiments, the method of converting polyethylene to propylene is performed at about 370oC. In embodiments, the method of converting polyethylene to propylene is performed at about 380oC. In embodiments, the method of converting polyethylene to propylene is performed at about 300oC. In embodiments, the method of converting polyethylene to propylene is performed at about 400oC. In embodiments, the method of converting polyethylene to propylene is performed at about 410oC. In embodiments, the method of converting polyethylene to propylene is performed at about 420oC. In embodiments, the method of converting polyethylene to propylene is performed at about 430oC. In embodiments, the method of converting polyethylene to propylene is performed at about 440oC. In embodiments, the method of converting polyethylene to propylene is performed at about 450oC. In embodiments, the method of converting polyethylene to propylene is performed at about 460oC. In embodiments, the method of converting polyethylene to propylene is performed at about 470oC. In embodiments, the method of converting polyethylene to propylene is performed at about 480oC. In embodiments, the method of converting polyethylene to propylene is performed at about 490oC. In embodiments, the method of converting polyethylene to propylene is performed at about 500oC.

[0072] In embodiments, the method of converting polyethylene to propylene is performed ata temperature above 250oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 260oC.In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 270oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 280oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperaturePATENT Attorney Docket No.: 052103-531001WO above 290oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 300oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature baove 310oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 320oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 330oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 340oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 350oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 360oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 370oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 380oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 390oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 400oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 410oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 420oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 430oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 440oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 450oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 460oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 470oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 480oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 490oC. In embodiments, the method of converting polyethylene to propylene is performed at a temperature above 500oC.

[0073] In embodiments, the method of converting polypropylene to a mixture of propyleneand isobutylene is performed at about 150oC to about 550oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 200oC to about 500oC. In embodiments, the method of converting polypropylene to a mixture ofPATENT Attorney Docket No.: 052103-531001WO propylene and isobutylene is performed at about 250oC to about 450oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 300oC to about 400oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 300oC to about 350oC.

[0074] In embodiments, the method of converting polypropylene to a mixture of propyleneand isobutylene is performed at about 250oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 260oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 270oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 280oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 290oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 300oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 310oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 320oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 330oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 340oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 350oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 360oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 370oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 380oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 390oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 400oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 410oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 420oC. In embodiments, the method of converting polypropylene to aPATENT Attorney Docket No.: 052103-531001WO mixture of propylene and isobutylene is performed at about 430oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 440oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 450oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 460oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 470oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 480oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 490oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at about 500oC.

[0075] In embodiments, the method of converting polypropylene to a mixture of propyleneand isobutylene is performed at a temperature above 250oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 260oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 270oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 280oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 290oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 300oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 310oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 320oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 330oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 340oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 350oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 360oC. In embodiments, the method of converting polypropylene to a mixturePATENT Attorney Docket No.: 052103-531001WO of propylene and isobutylene is performed at a temperature above 370oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 380oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 390oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 400oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 410oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 420oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 430oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 440oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 450oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 460oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 470oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 480oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 490oC. In embodiments, the method of converting polypropylene to a mixture of propylene and isobutylene is performed at a temperature above 500oC.

[0076] In embodiments, the method of converting polyethylene to a C3 to C30 alkene isperformed at about 150oC to about 550oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 200oC to about 500oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 250oC to about 450oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 300oC to about 400oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 300oC to about 350oC.

[0077] In embodiments, the method of converting polyethylene to a C3 to C30 alkene isperformed at about 250oC.In embodiments, the method of converting polyethylene to a C3 toPATENT Attorney Docket No.: 052103-531001WO C30 alkene is performed at about 260oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 270oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 280oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 290oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 300oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 310oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 320oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 330oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 340oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 350oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 360oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 370oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 380oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 390oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 400oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 410oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 420oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 430oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 440oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 450oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 460oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 470oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 480oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 490oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at about 500oC.PATENT Attorney Docket No.: 052103-531001WO

[0078] In embodiments, the method of converting polyethylene to a C3 to C30 alkene isperformed at a temperature above 250oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 260oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 270oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 280oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 290oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 300oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 310oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 320oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 330oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 340oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 350oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 360oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 370oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 380oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 390oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 400oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 410oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 420oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 430oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 440oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 450oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 460oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 470oC. In embodiments,PATENT Attorney Docket No.: 052103-531001WO the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 480oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 490oC. In embodiments, the method of converting polyethylene to a C3 to C30 alkene is performed at a temperature above 500oC.

[0079] In embodiments, the catalyst is an olefin metathesis catalyst. In embodiments, theolefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support or oxide solid support.

[0080] In embodiments, the olefin metathesis catalyst comprises the transition metal selectedfrom W, Mo, a mixture of Co and Mo, Re, Ta, and Ru. In embodiments, the olefin metathesis catalyst comprises the transition metal selected from W, Mo, a mixture of Co and Mo, and Re. In embodiments, the olefin metathesis catalyst is W. In embodiments, the olefin metathesis catalyst is Mo. In embodiments, the olefin metathesis catalyst is a mixture of Co and Mo. In embodiments, the olefin metathesis catalyst is Re. In embodiments, the olefin metathesis catalyst is Ta. In embodiments, the olefin metathesis catalyst is Ru.

[0081] In embodiments, the olefin metathesis catalyst comprises the metal oxide solidsupport or oxide solid support selected from SiO2, mixed SiO2-Al2O3, gamma-phase Al2O3, Al2O3, TiO2, CeO2, MgO, ZrO2, MFI, and HBEA. In embodiments, the olefin metathesis catalyst comprises the metal oxide solid support or oxide solid support selected from SiO2, mixed SiO2-Al2O3, and gamma-phase Al2O3. In embodiments, the metal oxide solid support or oxidesolid support is SiO2. In embodiments, the metal oxide solid support or oxide solid support ismixed SiO2-Al2O3. In embodiments, the metal oxide solid support or oxide solid support is gamma-phase Al2O3. In embodiments, the metal oxide solid support or oxide solid support is Al2O3. In embodiments, the metal oxide solid support or oxide solid support is TiO2. Inembodiments, the metal oxide solid support or oxide solid support is CeO2. In embodiments, themetal oxide solid support or oxide solid support is MgO. In embodiments, the metal oxide solid support or oxide solid support is ZrO2. In embodiments, the metal oxide solid support or oxide solid support is MFI. In embodiments, the metal oxide solid support or oxide solid support is HBEA.PATENT Attorney Docket No.: 052103-531001WO

[0082] In embodiments, the amount of the transition metal per unit surface area of the solidsupport is about 0.05 to about 3.0 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.1 to about 2.5 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.2 to about 2.0 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.3 to about 1.5 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.4 to about 1.0 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.1 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.2 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.3 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.4 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.5 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.6 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.7 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.8 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 0.9 atoms per nm2. In embodiments, the amount of the transition metal per unit surface area of the solid support is about 1.0 atoms per nm2.

[0083] In embodiments, the catalyst is a basic olefin isomerization catalyst. In embodiments,the basic olefin isomerization catalyst comprises an alkali metal dispersed on a solid support.

[0084] In embodiments, the basic olefin isomerization catalyst comprises the alkali metalselected from Na, K, Li, Na / K mixture, Rb, and Cs. In embodiments, the basic olefin isomerization catalyst comprises the alkali metal selected from Na, K, Li, and Na / K mixture. In embodiments, the basic olefin isomerization catalyst is Na. In embodiments, the basic olefin isomerization catalyst is K. In embodiments, the basic olefin isomerization catalyst is Li. In embodiments, the basic olefin isomerization catalyst is the Na / K mixture. In embodiments, thePATENT Attorney Docket No.: 052103-531001WO basic olefin isomerization catalyst is Rb. In embodiments, the basic olefin isomerization catalyst is Cs.

[0085] In embodiments, the solid support is selected from SiO2, gamma-phase Al2O3, TiO2,CeO2, MgO, CaO, and an aluminosilicate zeolite. In embodiments, the solid support is selected from SiO2 and gamma-phase Al2O3. In embodiments, the solid support is SiO2. In embodiments,the solid support is gamma-phase Al2O3. In embodiments, the solid support is TiO2. Inembodiments, the solid support is CeO2. In embodiments, the solid support is MgO. In embodiments, the solid support is CaO. In embodiments, the solid support is aluminosilicate zeolite. In embodiments, the solid support includes additional metals such as trace amounts or as impurities. In embodiments, additional metals include Pd, Ir, Ru, Fe, Co, Mn, Ni, Cu, Cr, V, Sc, Ti, Zr, Ga,La, Rh, Os, and Pt.

[0086] In embodiments, the basic olefin isomerization catalyst comprises an alkali metaloxide or alkali metal hydroxide. In embodiments, the alkali metal oxide or alkali metal hydroxide is selected from MgO, CaO, Na2O, Li2O, and K2O. In embodiments, the alkali metal oxide or alkali metal hydroxide is MgO. In embodiments, the alkali metal oxide or alkali metal hydroxide is CaO. In embodiments, the alkali metal oxide or alkali metal hydroxide is Na2O. In embodiments, the alkali metal oxide or alkali metal hydroxide is Li2O. In embodiments, the alkali metal oxide or alkali metal hydroxide is K2O.

[0087] In embodiment, a method of preparation of an ankali metal on alumina catalystcomprises a step of contacting the alumina directly with the alkali metal. In another embodiment, a method of preparation of an ankali metal on alumina catalyst comprises a step of incipient wetness impregnation of a salt to a support and a step of calcination to thermally decompose to an alkali metal aluminum salt. In embodiments, the salt is an azide salt. In embodiments, the salt is a nitrate salt. In embodiments, the salt is a carbonate salt. In embodiments, the non-limiting example is K2O / Al2O3 catalyst, which is prepared by impregnating alumina with K2CO3 and heating the mixture at 500-800oC under a flow of air.

[0088] In embodiments, the alkali metal is about 0.1 to about 100 weight % of said basicolefin isomerization catalyst. In embodiments, the alkali metal is about 1.0 to about 50 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 1.5 to aboutPATENT Attorney Docket No.: 052103-531001WO 30 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 2 to about 20 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 5 to about 10 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 1 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 2 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 3 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 4 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 5 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 6 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 7 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 8 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 9 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 10 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 11 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 12 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 13 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 14 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 15 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 16 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 17 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 18 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 19 weight % of said basic olefin isomerization catalyst. In embodiments, the alkali metal is about 20 weight % of said basic olefin isomerization catalyst.

[0089] In embodiments, the alkali metal is sodium.

[0090] In embodiments, sodium, as a sodium metal, is in a range of 1 to 15 sodium atoms persquare nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is in a range of 2 to 14 sodium atoms per square nanometer of solid support surface. In embodiments, sodium, as a sodium metal, is in a range of 3 to 13 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is in a range of 4 to12 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodiumPATENT Attorney Docket No.: 052103-531001WO metal, is in a range of 5 to 11 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is in a range of 6 to 10 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is in a range of 7 to 9 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 1 sodium atom per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 2 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 3 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 4 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 5 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 6 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 7 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 7.5 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 8 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 9 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 10 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 11 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 12 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 13 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 14 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a sodium metal, is present as 15 sodium atoms per square nanometer of solid support surface area.

[0091] In embodiments, sodium, as a solution of sodium carbonate, is in a range of 1 to 15sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is in a range of 2 to 14 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is in aPATENT Attorney Docket No.: 052103-531001WO range of 3 to 13 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is in a range of 4 to12 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is in a range of 5 to 11 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is in a range of 6 to 10 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is in a range of 7 to 9 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 1 sodium atom per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 2 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 3 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 4 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 5 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 6 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 7 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 7.5 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 8 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 9 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 10 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 11 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 12 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 13 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution of sodium carbonate, is present as 14 sodium atoms per square nanometer of solid support surface area. In embodiments, sodium, as a solution ofPATENT Attorney Docket No.: 052103-531001WO sodium carbonate, is present as 15 sodium atoms per square nanometer of solid support surface area.

[0092] In embodiments, the basic olefin isomerization catalyst comprises one or moreadditional metals in addition to an alkali metal, including, but not limited to, sodium. In embodiments, the basic olefin isomerization catalyst further comprises a transition metal. In embodiments, the basic olefin isomerization catalyst further comprises Fe. In embodiments, the concentration of Fe is 0.001 to 5.0 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.05 to 2.0 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.01 to 1.0 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.05 to 0.5 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.01 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.02 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.03 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.04 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.05 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.06 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.07 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.08 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.09 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.1 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.2 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.3 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.4 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.5 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.6 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, thePATENT Attorney Docket No.: 052103-531001WO concentration of Fe is 0.7 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.8 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 0.9 Fe atoms per square nanometer of catalyst / solid support surface area. In embodiments, the concentration of Fe is 1.0 Fe atoms per square nanometer of catalyst / solid support surface area.

[0093] In embodiments, dimethyl ether is used to regenarate the olefin isomerizationcatalyst. In embodiments, the concentration of dimethyl ether is from 1% to 50%. In embodiments, the concentration of dimethyl ether is from 5% to 45%. In embodiments, the concentration of dimethyl ether is from 10% to 30%. In embodiments, the concentration of dimethyl ether is from 15% to 25%. In embodiments, the concentration of dimethyl ether is about 1%. In embodiments, the concentration of dimethyl ether is about 2%. In embodiments, the concentration of dimethyl ether is about 3%. In embodiments, the concentration of dimethyl ether is about 4%. In embodiments, the concentration of dimethyl ether is about 5%. In embodiments, the concentration of dimethyl ether is about 6%. In embodiments, the concentration of dimethyl ether is about 7%. In embodiments, the concentration of dimethyl ether is about 1%. In embodiments, the concentration of dimethyl ether is about 8%. In embodiments, the concentration of dimethyl ether is about 9%. In embodiments, the concentration of dimethyl ether is about 10%. In embodiments, the concentration of dimethyl ether is about 15%. In embodiments, the concentration of dimethyl ether is about 20%. In embodiments, the concentration of dimethyl ether is about 25%. In embodiments, the concentration of dimethyl ether is about 30%. In embodiments, the concentration of dimethyl ether is about 35%. In embodiments, the concentration of dimethyl ether is about 10%. In embodiments, the concentration of dimethyl ether is about 45%. In embodiments, the concentration of dimethyl ether is about 50%.

[0094] In embodiments, a regeneration temperature for olefin isomerization catalyst is about300oC to about 500oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 325oC to about 475oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 350oC to about 450oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 325oC to about 425oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 375oC to about 400oC. InPATENT Attorney Docket No.: 052103-531001WO embodiments, a regeneration temperature for olefin isomerization catalyst is about 300oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 325oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 350oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 375oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 400oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 425oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 450oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 475oC. In embodiments, a regeneration temperature for olefin isomerization catalyst is about 500oC.

[0095] In embodiments, the catalyst is an acidic olefin isomerization catalyst. Inembodiments, the acidic olefin isomerization catalyst is selected from MFI, MEL, BEA, MTF, chlorinated metal or metal oxide, fluorinated metal or metal oxide, and sulfated metal or metal oxide. In embodiments, the acidic olefin isomerization catalyst is MFI. In embodiments, the acidic olefin isomerization catalyst is MEL. In embodiments, the acidic olefin isomerization catalyst is BEA. In embodiments, the acidic olefin isomerization catalyst is MTF. In embodiments, the acidic olefin isomerization catalyst is chlorinated metal or metal oxide. In embodiments, the acidic olefin isomerization catalyst is fluorinated metal or metal oxide. In embodiments, the acidic olefin isomerization catalyst is sulfated metal or metal oxide.

[0096] In embodiments, the chlorinated metal or metal oxide is chlorinated alumina.

[0097] In embodiments, the fluorinated metal or metal oxide is fluorinated alumina.

[0098] In embodiments, the sulfated metal or metal oxide is sulfated tantalum oxide.

[0099] In embodiments, the catalyst is a transition metal olefin isomerization catalyst. Inembodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support.

[0100] In embodiments, the transition metal olefin isomerization catalyst comprises a metal,a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, Ru, Fe, Co, Rh, Os, and Pt. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on aPATENT Attorney Docket No.: 052103-531001WO solid support selected from Pd and Ir. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, and Ru. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, Ru, and Fe. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, Ru, Fe, and Co. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, Ru, Fe, Co, and Rh. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, Ru, Fe, Co, Rh, and Os. In embodiments, the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide, or mixtures thereof, or a metal on a solid support selected from Pd, Ir, Ru, Fe, Co, Mn, Ni, Cu, Cr, V, Sc, Ti, Zr, Ga,La, Rh, Os, and Pt.

[0101] In embodiments, the transition metal olefin isomerization catalyst solid support isselected from SiO2, mixed SiO2-Al2O3, gamma-phase Al2O3,Al2O3, TiO2, CeO2, MgO, ZrO2, MFI, and BEA. In embodiments, the transition metal olefin isomerization catalyst solid supportis SiO2. In embodiments, the transition metal olefin isomerization catalyst solid support is mixedSiO2-Al2O3. In embodiments, the transition metal olefin isomerization catalyst solid support isgamma-phase Al2O3. In embodiments, the transition metal olefin isomerization catalyst solidsupport is Al2O3. In embodiments, the transition metal olefin isomerization catalyst solid supportis TiO2. In embodiments, the transition metal olefin isomerization catalyst solid support is CeO2.In embodiments, the transition metal olefin isomerization catalyst solid support is MgO. Inembodiments, the transition metal olefin isomerization catalyst solid support is ZrO2. Inembodiments, the transition metal olefin isomerization catalyst solid support is MFI. Inembodiments, the transition metal olefin isomerization catalyst solid support is BEA.

[0102] In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than1:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:2. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:3. InPATENT Attorney Docket No.: 052103-531001WO embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:4. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:5. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:6. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:7. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:8. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:9. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 1:10. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 2:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 3:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 4:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 5:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 6:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 7:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 8:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 9:1. In embodiments, the ratio of a tungsten catalyst to a sodium catalyst is greater than 10:1.

[0103] In embodiments, the greater than 1:1 ratio of a tungsten catalyst and a sodium catalystprovides a higher proportion of chain straightening in a polypropylene reactant.

[0104] In embodiments, the use of a chlorinated tungsten catalyst provides a higherproportion of chain straightening in a polypropylene reactant.

[0105] In embodiments, olefins are not installed in the polyolefin chains with a prior orconcurrent alkane dehydrogenation step.

[0106] In embodiments, the alkane dehydrogenation catalyst is not iridium ligated bytridentate pincer ligands, wherein the tridentate pincer ligand is a phosphinous acid derivative.

[0107] In embodiments, the alkane dehydrogenation catalyst is not iridium ligated bytridentate pincer ligands, wherein the tridentate pincer ligand is phosphinous acid, bis(1,1- dimethylethyl)-, 5-methoxy-1,3-phenylene ester.PATENT Attorney Docket No.: 052103-531001WO

[0108] In embodiments, the alkane dehydrogenation catalyst is not iridium ligated bytridentate pincer ligands, wherein the tridentate pincer ligand is phosphinous acid, bis(1,1- dimethylethyl)-, 1,3-phenylene ester.

[0109] In embodiments, the alkane dehydrogenation catalyst is not platinum on gammaphase alumina.

[0110] In embodiments, alkane dehydrogenation catalyst is not bimetallic platinum-tin ongamma phase alumina.

[0111] In embodiments, the alkane dehydrogenation catalyst and / or the olefin isomerizationcatalyst is not bimetallic platinum-zinc on silica.

[0112] In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalystis not ruthenium with one or more ligands, wherein the ligand is a phosphine, and wherein the phosphine is tricyclohexylphosphine.

[0113] In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalystis not ruthenium with one or more ligands, wherein the ligand is an N-heterocyclic carbene, and wherein the carbene is 1,3-Bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene. In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalyst is not ruthenium with one or more ligands, wherein the ligand is an N-heterocyclic carbene, and wherein the carbene is 1-(2,6-diethylphenyl)-3,5,5-trimethyl-3-phenylpyrrolidin-2-ylidene. In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalyst is not ruthenium with one or more ligands, wherein the ligand is an N-heterocyclic carbene, and wherein the carbene is any bicyclic alkyl amino carbene.

[0114] In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalystis not molybdenum with one or more ligands, wherein the ligand is an alkoxide. In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalyst is not molybdenum with one or more ligands, wherein the ligand is an imido moiety.

[0115] In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalystis not methyltrioxorhenium on a support, wherein the support is a mixed silica alumina. In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalyst is notPATENT Attorney Docket No.: 052103-531001WO methyltrioxorhenium on a support, wherein the support is a gamma phase alumina. In embodiments, the olefin metathesis catalyst and / or the olefin isomerization catalyst is not methyltrioxorhenium on a support, wherein the support is chlorinated.

[0116] In embodiments, the olefin isomerization catalyst is not palladium ligated by aphosphine, wherein the phosphine is tritertbutylphosphine.

[0117] In embodiments, the olefin isomerization catalyst is not ruthenium ligated by aphosphine, wherein the phosphine is triphenylphosphine.

[0118] In embodiments, the method of conversion of a polyolefin to an olefin is not theisomerising ethenolysis of monounsaturated polyethylene or polypropylene, where the olefin originates from the termination of a polymerization reaction.

[0119] In embodiments, the method of conversion of a polyolefin to an olefin is not thecombination of catalytic cracking, cross-metathesis with ethylene, and olefin isomerization to convert olefins with a carbon number of 6 or less to propylene, isobutylene, or a combination thereof.

[0120] It is understood that the examples and embodiments described herein are forillustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes. EXAMPLES

[0121] We show that the simple combination of tungsten oxide on silica and sodium metal ongamma-alumina transforms polyethylene, polypropylene, or a mixture thereof, including post- consumer forms of these materials, to propylene, a mixture of propylene and isobutylene, or higher olefins, i.e., C3-C30, in greater than 90% yield at 320 °C without the need for dehydrogenation of the starting polyolefins. These catalysts used commercially for decades can be recycled for this process through multiple cycles with little change in reactivity.

[0122] Light olefins, such as ethylene, propylene, and butenes, are among the largest volumecommodity chemicals (17). Recently, our group, as well as Scott, Guironnet, and coworkers (18,PATENT Attorney Docket No.: 052103-531001WO 19), independently showed that isomerizing ethenolysis (IE), which is a catalytic process that converts internal or terminal olefins to shorter terminal olefins by a combination of olefin isomerization and olefin metathesis (FIG.1B) (20, 21), can produce propylene with high selectivity from dehydrogenated or terminal unsaturated polyethylene (22). Tuba and coworkers have also shown that IE can convert medium chain alkenes (C6-C18) to propylene (23, 24). However, IE has not been observed with PP, the second most abundant waste plastic. Because PE and PP are nearly impossible to separate from each other in a mixed waste stream, it is crucial that an IE process occurs with both polyolefins. In addition, the previous IE reaction on PE required homogeneous catalysts that were expensive and not recyclable (18, 19). These drawbacks create the need to discover a base-metal heterogeneous catalyst system for the IE of both PE and PP to produce light olefins selectively.

[0123] We report a distinct approach to the deconstruction of both PE and PP to propyleneand isobutylene that bypasses the need for polymer dehydrogenation or unsaturated polymer and occurs with base-metal catalysts comprising tungsten oxide on silica (WO3 / SiO2) and sodium metal on gamma-phase alumina (Na / γ-Al2O3). These reactions are initiated by a combination of catalytic cracking by the W- or Na-containing catalysts, which also, together, convert PE and PP to propylene and a combination of propylene and isobutylene, respectively. These reactions occur in greater than 90% yield in 90 minutes without competing generation of methane. Because WO3 / SiO2 has been used industrially as an olefin metathesis catalyst in olefin conversion technology (OCT, > 5 MT / yr) and in the neohexene process (> 250 kT / yr) (25-27), and alkali metals supported on alumina have been used industrially as olefin isomerization catalysts for the Shell Higher Olefin process (SHOP, > 1 MT / yr) (26, 28), the conversion of PE to propylene and PP to propylene and isobutylene with these two catalysts constitutes a major step toward scalable, robust, and selective conversion of PE, PP and mixtures of the two polymers to light olefins.

[0124] We began our studies on polyolefin deconstruction to light olefins with heterogeneouscatalysts by addressing the necessity of an initial dehydrogenation step to create unsaturation in the polymer chains for IE. Prior work has shown that dehydrogenation of PE can be achieved with a transition metal-based homogeneous catalyst together with stoichiometric hydrogen acceptors or, alternatively, with a transition metal-based heterogeneous catalyst. However,PATENT Attorney Docket No.: 052103-531001WO dehydrogenation with the heterogeneous catalysts is accompanied by aromatization and hydrogenolysis of the polymer. Transfer dehydrogenation of PP with molecular catalysts has been demonstrated (29), but heterogeneous dehydrogenation of PP has not been reported. Hence, there is a need to identify heterogeneous catalysts for dehydrogenation of PE and PP that do not concurrently generate methane or arenes (30).

[0125] We hypothesized that the difficulties confronting PE and PP dehydrogenation couldbe circumvented and the dependence on precious metals could be eliminated by using catalytic chain scission to form shorter polymer chains containing C=C bonds that could be used for subsequent IE. We further hypothesized that a basic catalyst could effect this chain cleavage step without promoting skeletal isomerization of PE and could catalyze isomerization of the olefins during concomitant IE (31). If so, then PE could be converted selectively to propylene, and PP could be converted selectively to propylene and isobutylene by a combination of catalytic cracking and isomerizing ethenolysis (CIE), as shown in FIG.1C.

[0126] To investigate the feasibility of this strategy, we subjected isotactic PP (iPP, Aldrich,Mn = 28.0 kDa) and HDPE (Aldrich, Mn = 9.10 kDa) to Na / γ-Al2O3 at under 15 bar of ethylene 320 °C. After 90 min of heating, the iPP subjected to these conditions contained approximately 3.1% trisubstituted olefin and 0.27% 1,1-disubstituted olefin, with respect to propylene repeat units, as determined by1H NMR spectroscopy (FIG.2A). Likewise, HDPE subjected to these conditions contained approximately 0.48 ± 0.11% internal olefin (standard deviation, average of three runs). HDPE heated under the same conditions in the absence of catalyst contained 0.098 ± 0.008% (standard deviation, average of three runs) terminal olefin and <0.01% internal olefin (FIG.2A). Analysis by HT-SEC revealed that each of the recovered unsaturated polymers signaled measurable and similar reductions in molecular weight. The number-average molecular weight (Mn) of the starting iPP was 28.0 kDa, whereas the Mnof the same iPP heated at 320 °C in the presence of Na / γ-Al2O3 for 90 min was 1.63 kDa and that of the iPP heated at 320 °C in the absence of any additive for the same time was 1.75 kDa (FIG.2B). The Mn of the starting PE was 9.73 kDa, whereas the Mnof the PE after heating at 320 °C in the presence of Na / γ-Al2O3for 90 min was 2.25 ± 0.15 kDa, and the Mn of the PE heated at 320 °C for the same time in the absence of any additive was 3.18 ± 0.49 kDa. Thus, we conclude that heating PE and PPPATENT Attorney Docket No.: 052103-531001WO mediates scission of the polymer chains but heating in contact with Na / γ-Al2O3leads to the combined scission of polymer chains and formation of olefins.

[0127] Having observed that Na / γ-Al2O3 catalyzes the cleavage of PP and PE at320 °C to long-chain alkenes, and knowing from prior work that Na / γ-Al2O3catalyzes alkene isomerization (35) we sought a similarly simple and robust catalyst for olefin metathesis and tested whether this species could also catalyze cracking of the polyolefin chains. We reasoned that WO3 / SiO2could be an effective olefin metathesis catalyst under these conditions because it has been reported to catalyze ethenolysis of both linear and branched olefins at temperatures between 300 and 400 °C (32). Thus, we synthesized WO3 / SiO2 according to previous work by Howell et al. showing that a catalyst with 0.6 W atoms per square nanometer on silica support was most active for the self-metathesis of propylene (33). Upon contacting iPP with WO3 / SiO2at 320 °C under ethylene in the absence of Na / γ-Al2O3, we observed degradation of the polymer into an oil containing 11.9% olefin with respect to PP repeat units. This level of olefin formation is three times that observed in samples of iPP contacted with ethylene and Na / γ-Al2O3alone (FIG.2A). HDPE contacted with ethylene and WO3 / SiO2 under the same conditions produced only 0.21 ± 0.09% internal olefin and possessed a Mn of 2.82 ± 0.44 kDa. These data show that iPP in the presence of the WO3 / SiO2undergoes chain cleavage and formation of olefins to a much larger extent than does PE. They also show that iPP in the presence of the WO3 / SiO2undergoes chain cleavage and formation of olefins to a larger extent than it does in the presence of Na / ^-Al2O3,but that PE in the presence of WO3 / SiO2undergoes chain cleavage and formation of olefins to a smaller extent than it does in the presence of Na / ^-Al2O3. We recognized that this unexpected cracking of the polyolefin chains to form alkenes in the presence of these alkene isomerization and olefin metathesis catalysts could prevent the need for a separate catalyst that would generate alkenes in the polymer or for a polyolefin that contains alkene chain ends.

[0128] Having shown that WO3 / SiO2 cleaved iPP to shorter chain alkenes, we tested the fullCIE of PP to light alkenes catalyzed by the combination of WO3 / SiO2and Na / γ-Al2O3. The reaction of various sources of PP under 15 bar of ethylene at 320 °C formed an approximately 2:1 ratio of propylene to isobutylene. For example, a commercial sample of iPP (Sigma-Aldrich, 68 kDa) converted to a mixture of propylene in 145% yield with respect to monomer units and isobutylene in 87% yield after 90 min, and the reaction of atactic polypropylene (aPP) formed aPATENT Attorney Docket No.: 052103-531001WO slightly lower, but still high, yield of propylene (137%) and isobutylene (74%) (FIG.2C). The selectivity for isobutylene against all other butene isomers in these experiments was 77% and 92.8% respectively. Simple IE of monounsaturated PP would yield one equivalent of propylene and one equivalent of isobutylene per monomer unit converted. Thus, the amount of propylene formed in this process is greater than the amount of isobutylene and greater than the amount the stoichiometry predicts. We hypothesized that this 2:1 ratio of propylene to isobutylene could result from skeletal isomerization of the polypropylene backbone by the acidic WO3 / SiO2catalyst.

[0129] Consistent with this explanation for the observed stoichiometry of products, thesample of iPP contacted with WO3 / SiO2at 320 °C for 90 min incorporated approximately 25.2% of the methyl groups into the polymer backbone as methylene units, as determined by1H NMR spectroscopy. This extent of isomerization corresponds to a theoretical yield of 150% propylene and 75% isobutylene with respect to PP monomer units, and this ratio matches closely the yields observed in our CIE experiments. The same isomerization was not observed for iPP contacted with Na / γ-Al2O3 under the same conditions. We envision an enhancement of backbone isomerization could drive the selectivity of the CIE of PP towards propylene, enabling the full conversion of PP to the monomer from which it was made, an outcome which might be preferable if propylene were judged to be the preferred product rather than a combination of propylene and isobutylene as the sole butene isomer.

[0130] The combination of WO3 / SiO2 and Na / γ-Al2O3 also catalyzed the deconstruction ofvarious classes of polyethene selectively to propylene (FIG.2C). The reaction of HDPE (Sigma- Aldrich, Mn = 9.10 kDa) with ethylene (15 bar) formed propylene in 87% yield (565 TON in W, Figure 2C) in less than 90 min (average TOR of 0.11 s-1) at 320 °C. Concomitant consumption of ethylene was also observed; 62.5 mmol of ethylene were consumed and 62.2 mmol of propylene were produced, illustrating good closure of the mass balance for this process. In a similar fashion, commercial samples of LDPE and LLDPE formed propylene with the same catalyst, temperature, and time in yields of 97% and 93%, respectively. For each of these reactions, methane was used as the internal standard. To assess whether methane was generated during the reaction, we conducted an identical CIE of HDPE in the absence of added methane as an internalPATENT Attorney Docket No.: 052103-531001WO standard. We found that only 0.018 mmol of methane were generated in the reaction (assuming the same yield of propylene), amounting to less than 0.25% yield of methane from the HDPE.

[0131] The inability to separate PE from PP in a mixed waste stream makes it important todemonstrate the deconstruction of a mixture of both polymers. Thus, we tested CIE on a 1.2:1 (w / w) mixture of HDPE to iPP (FIG.2C). This reaction converted all the polymer to a mixture of propylene and isobutylene in a 5.7:1 ratio, for a yield of 89% and 83% propylene and isobutylene, respectively (FIG.2C). The ratio of propylene to isobutylene is slightly higher than expected for a 1.2:1 (w / w) mixture of PE to PP (4.6:1), further consistent with backbone isomerization of the PP chains within the mixture of PE and PP.

[0132] We also tested this catalyst system for the CIE of post-consumer waste (FIG. 2D). A1.0-gallon jug selected as a source of waste HDPE produced propylene in a yield of 93% that is comparable to that for CIE of a commercial sample of virgin HDPE. A centrifuge tube selected as a source of waste polypropylene formed a 2.0:1 ratio of propylene and isobutylene in yields of 156% and 79%, respectively, which are comparable to that for CIE of commercial, virgin iPP and, again, reflects some skeletal isomerization of the PP backbone. The selectivity for isobutylene against other butene isomers was 91%. A bread bag chosen as representative food packaging that is a composite material containing several different polymers also reacted in high yield. Characterization of this bread bag by quantitative1H NMR spectroscopy revealed that the material was 65% PE by mass. This source of LDPE, thus, yielded propylene in a yield of 81.3%, which is only slightly lower than that obtained from CIE of commercial, virgin LDPE

[0133] To investigate the robustness of the CIE approach for use on a post-consumer wastestream, we conducted CIE on HDPE with added contaminants. We found that adding 5% (w / w) of PS to the reaction mixture did not impact the CIE of HDPE to a large extent. However, addition of 5 wt% of PVC or PET to the reaction mixture decreased the yield of propylene to 20.5% and 16.9%, respectively. Likewise, CIE of HDPE in the presence of 5.0 wt% of the plasticizer bis(2-ethylhexyl) phthalate (DEHP) resulted in a significantly diminished propylene yield of 25.7%. We note that the separation of polyolefins from contaminants such as PET or PVC by floatation is well precedented, as is the removal of PVC or of catalyst-poisoning chlorine from a mixed-waste stream by thermal decomposition and recovery of the resulting HClPATENT Attorney Docket No.: 052103-531001WO (35). Therefore, application of the CIE approach to mixed waste stream would require separation of the contaminants from the polymer prior to its deconstruction, but such separation methods are established.

[0134] To assess whether the light olefins observed in the above experiments were producedfrom the polyolefin reactants and ethylene or from ethylene alone, we conducted an isotopic labeling experiment. We subjected a mixture of 95.5 wt% HDPE and 4.5 wt %13C2-PE or a mixture of 95.5 wt% iPP and 4.5 wt% 1-13C PP to our CIE approach. The resulting gaseous products of each CIE reaction were then analyzed by gas chromatography-mass spectrometry to determine the isotopic abundance of13C in the propylene product. We found a13C isotopic abundance of 8.35 ± 0.63% in the propylene originating from PE, and an abundance of 5.68 ± 1.46% for propylene originating from PP (errors represent one standard deviation resulting from three separate measurements) (FIG.3A). These levels of13C enrichment correspond to a 101% yield of13C propylene from PE and an 84.4% yield from PP. These levels of enrichment also correspond to an 88.8% yield of12C-propylene from PE and a 130% yield from PP. As noted above, this yield of propylene from PP results from parallel skeletal isomerization of the PP that incorporates12C methyl groups into the PP backbone to undergo IE. This labeling experiment shows that the propylene from the CIE of pure, unlabeled PE above originated almost exclusively from the PE and not from the ethylene

[0135] To determine the stability of this catalyst system, we conducted multiple cycles ofCIE using the same batch of catalyst. After the CIE of HDPE was conducted as described above, we terminated the reaction and dismantled the reactor under inert atmosphere. An additional portion of HDPE was added to the same catalyst, and the reaction was conducted in an identical manner. This process was repeated three times. We observed that the system retained 50% activity after each subsequent run, for a total TON of 1030 with respect to W over the three runs (FIG.3B). This value is more than an order of magnitude higher than the TON we reported previously for the IE of unsaturated HDPE using a molecular olefin metathesis catalyst and occurs directly on HDPE without initial dehydrogenation or the need for the polyolefin to contain one or more alkene units. Moreover, addition of a fresh portion of the Na / γ-Al2O3 catalyst in the second reaction cycle completely restored the activity of the system for two newPATENT Attorney Docket No.: 052103-531001WO reaction cycles, demonstrating that both catalysts can be recycled over multiple reactions (FIG. 3B).

[0136] Finally, we investigated the feasibility of conducting the CIE of polyolefins in a semi-batch reactor configuration. The CIE of HDPE under an ethylene flow of 10 standard cubic centimeters per minute (SCCM) at ambient pressure led to 26.9% yield of propylene, and reaction with an ethylene pressure of 20 bar and an ethylene flow of 200 SCCM formed propylene in a yield comparable to that of our batch experiments (84.5%, FIG.3C). The CIE of PP under the same conditions yielded propylene and isobutylene in 154% and 79.1% yield respectively. The selectivity for isobutylene over other butenes was 97%, even higher than that observed in our batch experiments. Given that reactive separation of isobutylene from a mixture of butenes is one of the most significant contributors to the cost of isobutylene production, this high selectivity could present an advantage of our CIE of PP over reactive separation (34).

[0137] With a continuous flow of ethylene, a reduced catalyst loading, and an increase in theamount of PE CIE to 50 g, we isolated the propylene product after 3 h of reaction by stepwise condensation of the efflux at 20 °C and -94 °C. The fraction collected at -94 °C constituted 90 mL (55 g using the density of liquid propylene at the boiling point) of a 3.6:1 mixture of liquified propylene and butenes, representing 438 TON with respect to WO3 / SiO2during this run (FIG. 3D). This experiment demonstrates the potential of operating the CIE process on a larger scale. The fraction condensed at 20 °C contained 20.0 g of a mixture of C5-C16olefins. Most of these higher olefins were pentenes (50.2%), hexenes (23.8%), and heptenes (13.2%), and the concentration of each olefin in the mixture was proportional to the vapor pressure of that olefin at 20 °C (see supplemental Figure S19). We, therefore, conclude that higher olefins could be produced with high selectivity using the CIE method by careful engineering of reactor residence time and outlet temperature. The isolation of both light olefins and higher olefins from the reaction mixture demonstrates the flexibility of CIE to generate light olefins with high selectivity for either one or two products or to generate mixtures of higher olefins.

[0138] The results of this work demonstrate the feasibility of deconstructing PE and PP, thetwo largest-volume plastics, individually or in a mixture to form products that are feedstockPATENT Attorney Docket No.: 052103-531001WO materials for the chemical industry using inexpensive heterogeneous catalysts that can be recycled and used in a semi-batch reactor. The work described in this study takes a large step toward creating practical methods to recover the carbon in PE and PP as propylene and isobutylene, which can be used to produce new polymers or other commodity chemicals. By doing so, the demand for production of these essential commodity chemicals starting from fossil carbon sources (e.g., petroleum and natural gas) and the associated greenhouse gas emissions could be greatly reduced. MATERIALS AND METHODS

[0139] All air-sensitive manipulations were conducted under an inert atmosphere in nitrogen-filled or argon-filled gloveboxes or by standard Schlenk techniques under nitrogen or argon. All reagents were purchased from commercial suppliers and used as received unless otherwisestated, with specific suppliers and lot numbers reported in Table 1 presented below.Table 1. List of Suppliers and Product Identifiers for Materials UsedPATENT Attorney Docket No.: 052103-531001WO

[0140] The headspaces of crude reaction mixtures were analyzed by gas chromatography(GC) on an Agilent 7820A GC system equipped with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. Quantitative analysis of the headspaces of crude reaction mixtures were conducted by gas chromatography (GC) with methane as an internal standard. Flash column chromatography was conducted with a Teledyne Isco CombiFlash® Rf system and RediSep Rf GoldTM columns. High-temperature size exclusion chromatography (HT-SEC) was performed on a Tosoh EcoSEC-HT with three TSKgel GMHhr-H(S) HT columns in series. Runs were performed at 135 ºC and 1 mL / min with 1,2,4-trichlorobenzene + 0.05% butylated hydroxytoluene (BHT) as mobile phase. Molecular weight was determined relative to linear polyethylene standards. N2adsorption experiments were performed using a Micromeritics Gemini VII BET instrument. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP- OES) was conducted using a Perkin-Elmer ICP Optima 7000 DV Spectrometer with Yttrium as internal standard. All NMR spectra were recorded at the University of California, Berkeley NMR facility. NMR spectra were recorded on an AV-600 instrument at 373 K with an operating frequency 600 MHz. NMR spectra of small molecules were recorded on an AV-600 instrument at 298 K with an operating frequency of 600 MHz. Chemical shifts (δ) are reported in ppm relative to that of the residual solvent signal (1,1,2,2-tetrachloroethane-d2δ = 6.0, CDCl3 δ = 7.28 for 1H NMR spectra). All high-pressure reactions were conducted in a series 4560 reactor manufactured by Parr Instrument company with high-temperature specification. The reactor heating and stirring were controlled by a series 4838 controller manufactured by Parr Instrument Company. The reactor was equipped with an impeller-type stirrer which was driven at 650 rpm, and a 1000 psi digital test pressure gauge with an accuracy of ± 0.25 % manufactured by SSI Technologies. Synthesis of Heterogeneous Catalysts Synthesis of WO3 / SiO2

[0141] This procedure was adapted from Howell and coworkers (24). SiO2 (Davisil Grade643) was first calcined to remove adsorbed water and organics.

[0142] SiO2 (5.5 g) was added to a quartz boat within a quartz tube and loaded into a tubefurnace. Under a flow of 100 mL / min of dry air, the furnace was heated to 120 °C at a rate of 3 °C / min and held for 3 h. The furnace was then heated to 550 °C at a rate of 3 °C / min and held forPATENT Attorney Docket No.: 052103-531001WO 5 h. The furnace was then cooled to room temperature. WO3 / SiO2was then synthesized by the incipient-wetness impregnation technique.

[0143] To the freshly-calcined SiO2 (5.000 g) was added a solution of 20.1 mM ammoniummetatungstate (5.740 mL, 0.1154 mmol metatungstate, 1.384 mmol W) in 500 µL increments. Between additions, the mixture was stirred with a spatula until uniform. The resulting mixture was then dried at room temperature for 2 h, and then placed in a 120 °C oven overnight. The resulting mixture was then loaded into a quartz boat and placed in a quartz tube in a tube furnace. The furnace was then heated to 120 °C at a rate of 3 °C / min and held for 2 h. The furnace was then heated to 550 °C at a rate of 3 °C / min and held for 5 h. The furnace was then cooled to room temperature. The catalyst was recovered and then transported under ambient atmosphere to a dry glovebox for long-term storage and use. Synthesis of Na / γ-Al2O3

[0144] γ-Al2O3 was first dried to remove any adsorbed water according to the followingprocedure.

[0145] To a 100 mL beaker was added γ-Al2O3 (40.0 g). The beaker was then placed withina 300 mL Parr reactor, which was sealed and evacuated to < 300 mTorr and backfilled with N2 three times, then once with ultra-high purity helium. A flow of helium (100 mL / min) was then initiated through the vessel, which was heated to 400 °C for 2 d. The reactor was then evacuated to 300 mTorr and allowed to cool to room temperature. The reactor was then backfilled with N2 and dismantled. The dried alumina was then collected.

[0146] To a flame dried thick-walled Schlenk vessel were added sodium (1.000 g, 43.50mmol) and dried γ-Al2O3 (10.00 g). The vessel was then sealed and heated to 200 °C for 18 h, resulting in the formation of a gray-blue solid. The mixture was then cooled, stored under inert atmosphere, and used in experiments without further modification. Synthesis of Fe / Al2O3

[0147] Gamma alumina (Thermo Fisher, Product No. 043832.A1) was received as pellets.These pellets were crushed manually with a pestle and mortar and sieved to obtain a uniform particle size distribution between 100 and 250 μm. The alumina was then dried in an oven at 160PATENT Attorney Docket No.: 052103-531001WO °C for at least 3 hours. The surface area and micropore characteristics of this alumina were then determined by physisorption of N2 using a Micromeritics Gemini VII instrument and analysis of the same by Brunauer–Emmett–Teller theory and the BJH method respectively. The surface area of the alumina was determined to be 252.18 m2per gram and the total pore volume was determined to be 0.62 mL per gram.

[0148] Fe / γ-Al2O3 was synthesized by the incipient-wetness impregnation method usingaqueous solutions of Iron (III) Nitrate prepared from the nonahydrate salt (trace metal grade, Thermo Fisher) and water purified to a resistance of 18.2 MΩ-cm using a MilliQ purification system. To several 1.000 g portions of the crushed, sieved, and dried alumina was added 0.620 mL of Iron (III) Nitrate solution in five 124 μL increments, with vigorous stirring between additions to ensure uniform dispersion of the solution. In each case the concentration of Iron (III) Nitrate solution was varied to deliver the desired quantity of iron atoms per square nanometer of support surface area. Specifically, a 0.675 mM solution of Iron (III) Nitrate was used to afford a catalyst with 0.001 iron atoms per square nanometer, a 6.75 mM solution for 0.010 iron atoms per square nanometer, a 20.3 mM solution for 0.030 iron atoms per square nanometer, a 33.8 mM solution for 0.050 iron atoms per square nanometer, a 67.5 mM solution for 0.100 iron atoms per square nanometer, and a 0.675 M solution for 1.00 iron atoms per square nanometer. Once the solution of Iron (III) Nitrate of the desired concentration was added to the alumina, the mixture was placed in a 160 °C oven for at least 3 hours to drive off excess water. The mixture was then added to a fritted quartz reactor tube connected to Swagelok ball valves using ultra-torr fittings on both ends. The reactor was then placed in a furnace and connected to a flow of ultra-zero grade air (Airgas) with a flow rate of 150 SCCM per minute. The reactor was then heated at a rate of 3 °C / minute to a final temperature of 600 °C, which was held constant for six hours. The reactor was then allowed to cool naturally to room temperature, purged with 150 SCCM of ultra pure helium for 15 minutes. The gas flow was then terminated, and the Swagelok valves at both ends of the reactor sealed to prevent exposure of the calcined catalyst to ambient air. The reactor assembly was then imported into a dry glovebox for long term storage and use. Synthesis of Na-Fe / γ-Al2O3

[0149] Na-Fe / γ-Al2O3 was synthesized by contacting Fe / γ-Al2O3 catalysts with moltensodium metal. Within a glovebox, the Fe / γ-Al2O3catalyst with the desired loading of Fe atomsPATENT Attorney Docket No.: 052103-531001WO per square nanometer (1.000 g) was combined with sodium metal (111.0 mg, 4.828 mmol) in a 20 mL scintillation vial. To the vial was added a small (4.5 x 12 mm, Fisher scientific) stir bar stripped of its PTFE coating. The vial was then sealed with a PTFE lined cap and placed in an aluminum heating block held at 200 °C. The vial was allowed to stir at this temperature for 18 h with a stir rate of 800 rpm. The vial was then allowed to cool to ambient temperature and imported into a glovebox for long term storage and use. Synthesis of Na2CO3-Fe / γ-Al2O3

[0150] Na2CO3-Fe / γ-Al2O3 was synthesized by incipient-wetness impregnation of Fe / γ-Al2O3 catalysts with aqueous solutions of Na2CO3. Fe / γ-Al2O3 (1.000 g) with 0.03 Fe atoms per square nanometer was added to a 20 mL scintillation vial and combined with aqueous sodium carbonate (620.0 μL) in five 124 μL additions. Between additions, the mixture was stirred manually with a spatula until completely homogeneous. The mixture was then placed in an oven held at 160 °C for 3 h. The mixture was then allowed to cool to ambient temperature and added to a fritted quartz reactor tube fitted with Swagelok ball valves on each end using ultra-torr fittings. The reactor tube was then connected to a flow of ultra-zero grade air (150 SCCM, Airgas) and heated to a temperature of 600 °C at a rate of 3 °C per minute. The reactor was then held at 600 °C for 6 h and allowed to cool thereafter to ambient temperature. The reactor was then purged with ultra high purity helium (150 SCCM, Airgas) for 15 minutes, after which the Swagelok valves were closed to seal the contents from atmospheric moisture. The reactor was then imported into the glovebox for long term storage and use. BET Analysis of Heterogeneous Catalysts and Supports

[0151] BET isotherms for WO3 / SiO2, Davisil 643 SiO2, and Strem γ-Al2O3 were collected asfollows:

[0152] Approximately 25 mg of each catalyst or support was accurately weighed in an oven-dried BET tube. The tube was then placed in an aluminum block at 120 °C under high vacuum (< 50 mTorr) for 18 h to remove adsorbed water. The dehydrated sample was then capped, accurately weighed once more, and then uncapped and quickly transferred to the Micromeritics Gemini VII BET instrument. N2isotherms were then collected at 77.4 K from a relative pressure of 0.050 to 1.000.PATENT Attorney Docket No.: 052103-531001WO

[0153] For Na / γ-Al2O3, the following alternative procedure was used:

[0154] An oven-dried BET tube was transferred under vacuum into an N2 filled drybox.

[0155] Na / γ-Al2O3 (60.2 mg) was then accurately weighed and added to the BET tube. TheBET tube was then sealed and transferred to the Micromeritics Gemini VII BET instrument, uncapped and quickly loaded for analysis. An N2 isotherm was then collected at 77.4 K from a relative pressure of 0.050 to 1.000.

[0156] The adsorption isotherms for Davisil 643 SiO2, Strem γ-Al2O3, Na / γ-Al2O3, andWO3 / SiO2are displayed in FIG.4.

[0157] The calculated surface areas, pore volumes, and average pore diameters for allcatalysts and supports are summarized in Table 2. Table 2. Surface Area and Porocity Values Calculated from N2 Adsorption Isotherms

[0158] The tungsten loading on WO3 / SiO2 was determined according to the followingprocedure:

[0159] WO3 / SiO2 (32.6 mg) was weighted accurately and digested according a previouslyreportedmprocedure. Specifically, the catalyst was added to a polypropylene centrifuge tube and HNO3 (5 wt % in water, 2.000 mL) and HF (50 wt % in water, 2.000 mL) were added to the catalyst. The mixture was then heated at 80 °C for 1 h. The resulting mixture was then neutralized with 16.6 M KOH (8.061 g) and filtered through a 0.45 μm PTFE syringe filter,PATENT Attorney Docket No.: 052103-531001WO which was washed five times with water. The filtrate was then diluted to a volume of 20 mL. A 1.000 mL aliquot of this solution was then diluted to 50 mL and used directly in analysis. The nominal concentration of W in this sample (given that the original catalyst contained 4.94 % W [w / w]) is 1.591 ppm (w / v). A blank sample was prepared in an identical manner without any added catalyst. An initial calibration standard with a concentration of 19.996 ppm W was prepared from an analytical standard (TraceCert, reported concentration 999.8 mg / L W) by diluting 1.000 mL of this standard to 50 mL with water. Four additional standards with W concentrations of 9.998, 3.9992, 1.9996, and 0.9998 ppm W were prepared by diluting 25, 10, 5, and 1 mL aliquots of this standard to a total volume of 50 mL respectively. These calibration standards, the digested catalyst sample, and the blank were then analyzed by ICP-OES on a Perkin-Elmer 7000 Optima DV instrument with yttrium as an internal standard. Wemission was measured at both 207.912 and 224.876 nm with 5 replicates per measurement. The results of the analysis are summarized in Table 3. Table 3. ICP-OES Emission Data

[0160] A plot of the W calibration curves is displayed in FIG. 5.

[0161] Calibration of W concentration using the emission line at 207.912 nm provided thefollowing calibration curve (S1): ^^207.912 = 57504.37[^^] − 21024.16 (S1, R2 = 0.9997) where I207.912 denotes the emission intensity at 207.912 nm and [W] is the concentration of tungsten in ppm (w / v).PATENT Attorney Docket No.: 052103-531001WO

[0162] Calibration of W concentration using the emission line at 224.876 nm provided thefollowing calibration curve (S2): ^^224.876 = 80676.74[^^] − 16289.92 (S2, R2 = 0.9998) where I224.876 denotes the emission intensity at 224.876 nm and [W] is the concentration of tungsten in ppm (w / v).

[0163] Using either of these calibration curves, the concentration of tungsten present in thesample solution was given by S3: [^^]^^ = (^^^^−^^^^)−^^^^ (S3) where [W]s denotes the concentration of tungsten present in the sample, Is denotes the emission intensity of the sample solution observed at either wavelength, Ib denotes the emission intensity of the blank solution observed at either wavelength, T represents the intercept of the calibration curve of either wavelength, and S represents the sensitivity of the calibration curve of either wavelength.

[0164] Using S3, the emission intensity of the sample solution at 207.912 nm corresponds toa W concentration of 1.5311 ± 0.0183 ppm (95 % CL). The emission intensity of the sample solution at 224.876 nm corresponds to a W concentration of 1.654 ± 0.084 ppm (95% CL). The average of these two measurements and propagation of their uncertainty provides a W concentration of 1.593 ± 0.043 ppm (95% CL), which contains the nominal concentration of 1.591 ppm. We therefore conclude that the actual loading of W in the WO3 / SiO2 catalyst is not significantly different from the nominal loading of 4.94 (w / w). General Method for the Isomerizing Ethenolysis of Polyethylenes

[0165] Within a nitrogen-filled glovebox, polyethylene (1.000 g, 35.65 mmol), WO3 / SiO2(400.0 mg, 0.110 mmol W, 0.0031 equiv.), and Na / γ-Al2O3(400.0mg, 1.740 mmol Na, 0.0488 equiv.) were combined in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and charged with 10.00 bar methane and 15.00 bar ethylene (175.4 mmol, 4.920 equiv.). The reactor was then heated to 320 °C, with stirring initiated after the reactor reached 150 °C. The reaction was allowed to stir at 320 °C for 90 min, and the headspace was then sampled for analysis by GC-FID. The reactor was then cooled to at least 30PATENT Attorney Docket No.: 052103-531001WO °C and was then vented and dismantled. The reaction vessel was then removed and weighed to quantify remaining polymer. General Method for the Isomerizing Ethenolysis of Polypropylenes

[0166] Within a nitrogen-filled glovebox, polypropylene (1.000 g, 23.76 mmol), WO3 / SiO2(400.0 mg, 0.110 mmol W, 0.0046 equiv.), and Na / γ-Al2O3 (400.0mg, 1.740 mmol Na, 0.0732 equiv.) were combined in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and charged with 10.00 bar methane and 15.00 bar ethylene (175.4 mmol, 4.920 equiv.). The reactor was then heated to 320 °C, with stirring initiated after the reactor reached 200 °C. The reaction was allowed to stir at 320 °C for 90 min, and the headspace was then sampled for analysis by GC-FID. The reactor was then cooled to at least 30 °C, at which point the reactor was vented and dismantled. The reaction vessel was then removed and weighed to quantify remaining polymer. General Method for the Isomerizing Ethenolysis of Mixed Polyolefins

[0167] Within a nitrogen-filled glovebox, polypropylene (496.1 mg, 11.8 mmol),polyethylene (701.1 mg, 25.2 mmol), WO3 / SiO2 (400.0 mg, 0.110 mmol W, 0.0046 equiv.), and Na / γ-Al2O3 (400.0mg, 1.740 mmol Na, 0.0732 equiv.) were combined in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and charged with 10.00 bar methane and 15.00 bar ethylene (175.4 mmol, 4.920 equiv.). The reactor was then heated to 320 °C, with stirring initiated after the reactor reached 200 °C. The reaction was allowed to stir at 320 °C for 90 min, and the headspace was then sampled for analysis by GC- FID. The reactor was then cooled to at least 30 °C, at which point the reactor was vented and dismantled. The reaction vessel was then removed and weighed to quantify remaining polymer. General Method for the Isomerizing Ethenolysis of HDPE in the Presence of Added Contaminants

[0168] Within a nitrogen-filled glovebox, high-density polyethylene (1.000 g, 35.65 mmol),the investigated contaminant (50.0 mg, 0.480 mmol PS, 0.800 mmol PVC, X0,260mmol PET, 0.128 mmol DEHP), WO3 / SiO2(400.0 mg, 0.110 mmol W, 0.0031 equiv.), and Na / γ-Al2O3(400.0 mg, 1.740 mmol Na, 0.0488 equiv.) were combined in a flame-dried 100 mL beaker. ThePATENT Attorney Docket No.: 052103-531001WO beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and charged with 10.00 bar methane and 15.00 bar ethylene (175.4 mmol, 4.920 equiv.). The reactor was then heated to 320 °C, with stirring initiated after the reactor reached 150 °C. The reaction was allowed to stir at 320 °C for 90 min, and the headspace was then sampled for analysis by GC-FID. Dehydrogenation and Isomerizing Ethenolysis of HDPE with Fe / γ-Al2O3 with WO3 / SiO2 (400.0The beaker was then placed in a 300 mL stirred Parr reactor, which was sealed and removed from the glovebox. The reactor was then charged with ethylene (15.00 bar) and methane (10.00 bar) and heated to 320 °C using a ceramic heating unit from Parr instruments. The reactor was then heated at 320 °C for 120 minutes, with t=0 defined as when the reactor temperature reached 310 °C (25-30 minutes from the start of heating). The headspace of the reaction was then sampled using a gas tight Hamilton syringe, and analyzed by GC-FID on an Agilent 7890A GC system fitted with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. The yield of propylene in each of these experiments is summarized below in FIG.19. Dehydrogenation and Isomerizing Ethenolysis of HDPE with Na2CO3-Fe / γ-Al2O3withWO3 / SiO2(400.0 mg, 0.1108 mmol W) and HDPE (1.000 g) in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL stirred Parr reactor, which was sealed and removed from the glovebox. The reactor was then charged with ethylene (15.00 bar) and methane (10.00 bar) and heated to 320 °C using a ceramic heating unit from Parr instruments. The reactor was then heated at 320 °C for 120 minutes, with t=0 defined as when the reactor temperature reached 310 °C (25-30 minutes from the start of heating). The headspace of the reaction was then sampled using a gas tight Hamilton syringe and analyzed by GC-FID on an Agilent 7890A GC system fitted with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. The yield of propylene in each of these experiments is summarized below in FIG.20.PATENT Attorney Docket No.: 052103-531001WO Dehydrogenation and Isomerizing Ethenolysis of Polypropylene with PtSn / γ-Al2O3, Na / γ- Al2O3, and WO3 / SiO2glovebox, polypropylene (2.500 g, 59.41 mmol), PtSn / γ-Al2O3(100.0 mg, 0.0140 mmol Pt), WO3 / SiO2 (400.0 mg), and Na / γ-Al2O3 (400.0 mg) were combined in a 100 mL flame-dried beaker. The beaker was then placed in a 300 mL Parr reactor, which was sealed and removed from the glovebox. The reactor was then charged with ethylene (10.0 bar) and methane (10.0 bar). The reactor was then heated to 340 °C for 16 h. The headspace of the reaction was then sampled using a gas tight Hamilton syringe and analyzed by GC-FID on an Agilent 7890A GC system fitted with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. The yield of propylene and isobutylene were calculated to be 7.65 mmol (12.9%) and 5.58 mmol (9.4%) respectively. Attempted Regeneration of Catalyst Mixture by Calcination in Air

[0172] After a DIE reaction where the reaction mixture comprised HDPE (1.000 g),WO3 / SiO2 (400.0 mg), and 10 wt% Na / γ-Al2O3 (400.0 mg) was concluded, the pressure vessel was allowed to cool to room temperature and vented to ambient pressure. Under ambient atmosphere, the spent catalyst mixture (approximately 800 mg) was loaded into a quartz reactor tube containing a glass frit and fitted on either end with Swagelok ball valves connected to the reactor tube with Swagelok Ultra-Torr fittings. The quartz reactor tube was then connected to a flow of air (Airgas, Ultra Zero grade, 150 SCCM) and heated to 600 °C at a ramp rate of 10 °C / min. The reactor was then heated at 600 °C for 3 h, after which the reactor was allowed to cool to room temperature. The reactor ball valves were then closed to seal the reactor from ambient atmosphere, and the reactor was disconnected from gas flow and imported to a dry glovebox.

[0173] The catalyst mixture (approximately 800 mg) was then combined with HDPE (1.000g) in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL stirred Parr reactor, which was sealed and removed from the glovebox. The reactor was then charged with ethylene (15.00 bar) and methane (10.00 bar) and heated to 320 °C using a ceramic heating unit from Parr instruments. The reactor was then heated at 320 °C for 120 minutes, with t=0 defined as whenPATENT Attorney Docket No.: 052103-531001WO the reactor temperature reached 310 °C (25-30 minutes from the start of heating). The headspace of the reaction was then sampled using a gas tight Hamilton syringe, and analyzed by GC-FID on an Agilent 7890A GC system fitted with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. The yield of propylene is recorded below in FIG.21. Attempted Regeneration of Catalyst Mixture by Calcination in Air Followed by Reduction with Hydrogen

[0174] After a DIE reaction where the reaction mixture comprised HDPE (1.000 g),WO3 / SiO2(400.0 mg), and 10 wt% Na / γ-Al2O3(400.0 mg) was concluded, the pressure vessel was allowed to cool to room temperature and vented to ambient pressure. Under ambient atmosphere, the spent catalyst mixture (approximately 800 mg) was loaded into a quartz reactor tube containing a glass frit and fitted on either end with Swagelok ball valves connected to the reactor tube with Swagelok Ultra-Torr fittings. The quartz reactor tube was then connected to a flow of air (Airgas, Ultra Zero grade, 150 SCCM) and heated to 600 °C at a ramp rate of 10 °C / min.The reactor was then heated at 600 °C for 3 h, at which point the gas flow was switched to Helium (Airgas, Ultra High Purity grade, 150 SCCM) for 30 minutes to purge out any remaining air. The flow was then switched to pure Hydrogen (Praxair, 100 SCCM) and held for 3 hours with the temperature maintained at 600 °C. The reactor was then allowed to cool to room temperature. The reactor ball valves were then closed to seal the reactor from ambient atmosphere, and the reactor was disconnected from gas flow and imported to a dry glovebox.

[0175] The catalyst mixture (approximately 800 mg) was then combined with HDPE (1.000g) in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL stirred Parr reactor, which was sealed and removed from the glovebox. The reactor was then charged with ethylene (15.00 bar) and methane (10.00 bar) and heated to 320 °C using a ceramic heating unit from Parr instruments. The reactor was then heated at 320 °C for 120 minutes, with t=0 defined as when the reactor temperature reached 310 °C (25-30 minutes from the start of heating). The headspace of the reaction was then sampled using a gas tight Hamilton syringe, and analyzed by GC-FID on an Agilent 7890A GC system fitted with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. The yield of propylene is recorded below in FIG.21.PATENT Attorney Docket No.: 052103-531001WO Regeneration of Dehydrogenation Catalysts with Dimethyl Ether

[0176] After each DIE reaction was concluded, the pressure vessel was allowed to cool toroom temperature and vented to ambient pressure. Under ambient atmosphere, the catalyst mixture (approximately 800 mg) was loaded into a quartz reactor tube containing a glass frit and fitted on either end with Swagelok ball valves connected to the reactor tube with Swagelok Ultra-Torr fittings. The quartz reactor tube was then connected to a flow of air (Airgas, Ultra Zero grade, 150 SCCM) and heated to 450 °C at a ramp rate of 10 °C / min. The reactor was then heated at 450 °C for 3 h, at which point the gas flow was switched to Helium (Airgas, Ultra High Purity grade, 150 SCCM) for 30 minutes to purge out any remaining air. The flow was then switched to 5% dimethyl ether in Helium (100 SCCM) and held for 30 minutes. The flow was then returned to pure Helium (150 SCCM) and held at 450 °C for 30 minutes, after which the reactor was allowed to cool to room temperature. The reactor ball valves were then closed to seal the reactor from ambient atmosphere, and the reactor was disconnected from gas flow and imported to a dry glovebox for use in subsequent experiments.

[0177] The catalyst mixture (771.0 mg) was then combined with HDPE (1.000 g) in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL stirred Parr reactor, which was sealed and removed from the glovebox. The reactor was then charged with ethylene (15.00 bar) and methane (10.00 bar) and heated to 320 °C using a ceramic heating unit from Parr instruments. The reactor was then heated at 320 °C for 120 minutes, with t=0 defined as when the reactor temperature reached 310 °C (25-30 minutes from the start of heating). The headspace of the reaction was then sampled using a gas tight Hamilton syringe, and analyzed by GC-FID on an Agilent 7890A GC system fitted with a GASPRO column (30 m x 0.320 mm, part number 113-4332) and an FID detector. The yield of propylene is recorded below in FIG.21. Procedures for Chain Scission Experiments 1. Chain Scission of Polymers in the Absence of Na / γ-Al2O3

[0178] Under ambient conditions, polyethylene (2.000 g, 71.30 mmol) or polypropylene(2.000g, 23.76) were added to a 100 mL beaker. The beaker was then loaded into a 300 mL high- temperature Parr reactor, which was sealed. The reactor was then connected to a Schlenk line, evacuated to a pressure less than 500 mTorr, and backfilled with N2 four times. The reactor wasPATENT Attorney Docket No.: 052103-531001WO then charged with 10 bar of methane and an additional 10 bar of ethylene. The reactor was then heated to 320 °C for 90 minutes. The reactor was then cooled to at least 30 °C and the headspace sampled for GC-FID analysis. The reactor was then vented to ambient pressure and dismantled. The resulting polymer mixture was then dissolved in 25 mL of boiling toluene, which was poured hot into 250 mL of room-temperature methanol with vigorous stirring. The beaker was then rinsed with an additional 25 mL of boiling toluene, which was poured hot into the same 250 mL of methanol with vigorous stirring. The resulting precipitated polymer was then collected by filtration and dried under high vacuum (< 100 mTorr) overnight. The resulting polymers were then characterized by1H NMR and HT-SEC.

[0179] Yield PE : 1.9089 g (95.445 % recovery)

[0180] Yield PP : 1.40 g (70% recovery).

[0181] The 1H NMR spectrum for PE is displayed in FIG. 6.

[0182] The 1H NMR spectrum for PP is displayed in FIG. 7.

[0183] HT-SEC chromatograms for PE and PP are displayed in FIG. 2B with calculated Mn,Mw, and PDI values summarized in Table 4. Table 4. Calculated Molecular Weight Data for Polymers from HT-SEC2. Chain Scission of Polymers by Na / γ-Al2O3

[0184] Within a nitrogen-filled glovebox, polyethylene (1.000 g, 35.65 mmol) orpolypropylene (1.000g, 23.76 mmol) was combined with Na / γ-Al2O3 (400.0 mg, 1.740 mmolPATENT Attorney Docket No.: 052103-531001WO Na) in a flame-dried 100 mL beaker. The beaker was then loaded into a 300 mL high-temperature Parr reactor, which was sealed, removed from the glovebox and charged with 10.00 bar of methane and an additional 15.00 bar of ethylene. The reactor was then heated at 320 °C for 90 minutes. The reactor was then cooled to at least 30 °C and the headspace sampled for GC-FID analysis. The reactor was then vented to ambient pressure and dismantled. The resulting polymer mixture (1.000 g, 23.76 mmol) was combined with Na / γ-Al2O3 (400.0 mg, 1.740 mmol Na) in a flame-dried 100 mL beaker. The beaker was then loaded into a 300 mL high-temperature Parr reactor, which was sealed, removed from the glovebox and charged with 10 bar of methane and an additional 15 bar of ethylene. The reactor was then heated at 320 °C for 90 minutes. The reactor was then cooled to at least 30 °C and the headspace sampled for GC-FID analysis. The reactor was then vented to ambient pressure and dismantled. The resulting polymer mixture was then dissolved in 25 mL of boiling toluene, which was poured hot into 250 mL of room- temperature methanol with vigorous stirring. The beaker was then rinsed with an additional 25 mL of boiling toluene, which was poured hot into the same 250 mL of methanol with vigorous stirring. The resulting precipitated polymer was then collected by filtration and dried under high vacuum (<100 mTorr) overnight. The resulting polymers were then characterized by1H NMR spectroscopy and HT-SEC.

[0185] Yield PE : 1.2530 g (89.50 % recovery as polymer and catalyst)

[0186] Yield PP : 0.7891 g (56.36 % recovery as polymer and catalyst)

[0187] The 1H NMR spectrum for PE is displayed FIG. 8.

[0188] The 1H NMR spectrum for PP is displayed in FIG. 9.

[0189] HT-SEC chromatograms for PE and PP are displayed in FIG. 2B, with calculated Mn,Mw, and

[0190] PDI values summarized in Table 4.3. Chain Scission and Skeletal Isomerization of PP by WO3 / SiO2

[0191] Under ambient conditions, polypropylene (1.000 g, 23.76 mmol) was combined withWO3 / SiO2 (400.0 mg, 0.110 mmol W) in a 100 mL beaker. The beaker was then loaded into a 300 mL high-temperature Parr reactor, which was sealed. The reactor was then connected to aPATENT Attorney Docket No.: 052103-531001WO Schlenk line, evacuated to a pressure less than 500 mTorr, and backfilled with N2 four times. The reactor was then charged with 10 bar of methane and an additional 15 bar of ethylene. The reactor was then heated at 320 °C for 90 minutes. The reactor was then cooled to at least 30 °C and the headspace sampled for GC-FID analysis. The reactor was then vented to ambient pressure and dismantled.

[0192] The resulting mixture of oil and solid catalysts was then washed with three 20 mLportions of pentanes, which were filtered through a 0.22 μm PTFE syringe filter cap. The resulting filtrate was then concentrated under vacuum to yield a pale yellow oil, which was characterized by 1H NMR.

[0193] Yield : 559.0 mg (55.9 % recovery)

[0194] The 1H NMR spectrum of the recovered oil is displayed in FIG. 10.Calculation of Olefin Content and Extent of Skeletal Isomerization by 1H NMR Olefin Content of Polyolefins

[0195] The olefin content of all polyethylenes was calculated as reported previously (17).The content of the 1,1-disubstituted and trisubstituted olefins on polypropylenes was calculated using previously reported chemical shifts of 4.80 ppm and 4.95 ppm in d2-TCE for the 1,1- disubstituted and trisubstituted isomers respectively (27). The integration intensities of these resonances were then normalized such that the total integration intensity of the olefin resonances and aliphatic resonances was equal to 600 (i.e.100 times the six protons per monomer unit). The concentration (in % relative to monomer units) of 1,1-disubstituted olefins in the polypropylene chains was then equal to half the integration intensity of the 1H NMR resonances corresponding to that isomer, and the concentration of trisubstituted olefins in the polypropylene chains equal directly to the integration intensity of the 1H NMR resonances corresponding to that isomer. Extent of Skeletal Isomerization of PP

[0196] The extent of skeletal isomerization of polypropylene was calculated from the 1HNMR spectrum in Figure S7 as follows. For polypropylene which has undergone no migration of methyl groupsinto the polymer backbone, the relative integration intensity of the 1H NMR resonances at 1.65, 1.33, and 0.95 ppm is 1 : 1 : 4, which correspond to one methylene proton,PATENT Attorney Docket No.: 052103-531001WO the methine proton, and the overlapping resonances of the remaining methylene proton and the methine proton (27). Upon isomerization to a linear segment, the three methyl protons at 0.95 ppm and the methine proton at 1.65 ppm are converted to four methylene protons at 1.33 ppm (Scheme S1).

[0197] the ratio ofthe integration intensity of the resonances at 1.65 and 0.95 ppm to the integration intensity of the resonance at 1.33 ppm. Thus, once the integration intensity is normalized to the intensity of the resonances at 0.95 and 1.65 ppm, the extent of skeletal isomerization can be estimated using the following equation: ^^1.33 = 1 + 6^^ where I1.33is the normalized integration intensity of the resonance at 1.33 ppm, and m represents the total polypropylene monomer units isomerized to three methylene units. Given that the overall integration intensity was normalized to the resonances at 1.65 and 0.95 ppm, the remaining polypropylene monomer units which have not undergone isomerization is 1 and the fraction of polypropylene monomer units converted to linear segments is given as: where L represents the fraction ofunits which have undergone skeletal isomerization. Thus, given that the normalized integration of the resonance at 1.33 ppm for a sample of PP exposed to WO3 / SiO2 under 15 bar of ethylene for 90 minutes was 3.09, we conclude that approximately 25.2 % of polypropylene monomer units underwent skeletal isomerization to yield additional methylene segments. If this is a representative extent of skeletalPATENT Attorney Docket No.: 052103-531001WO isomerization during the PIE of PP, the expected yield of propylene would be 150.3% with respect to monomer, and 74.8% isobutylene with respect to monomer. Preparation of Waste Polymers

[0198] For all sources of waste polymers, each object was cut with scissors to pieces lessthan 10 mm x 10 mm. These pieces (5.000g) were then dissolved in boiling toluene (125 mL) and precipitated in methanol (1.25 L) with vigorous stirring. The resulting suspension was then filtered, collected, and dried under vacuum (200 mTorr) for 18 h. The dry polymers were then ground in a coffee grinder to obtain a uniform powder which was used in experiments.

[0199] Additionally, for waste LDPE in particular the purity of the PE source wasdetermined by quantitative1H NMR spectroscopy (q1H NMR) according to the following procedure:

[0200] After preparation according to the above procedure, waste LDPE (10.3 mg, 0.367mmol) was added to an NMR tube with 1,3,5-Trimethoxybenzene (13.2 mg, 0.078 mmol). 1,1,2,2-Tetrachloroethane-d2(400 µL) was added and the mixture was heated in an aluminum block for 18 h to ensure a homogeneous mixture. A 1-D1H NMR experiment was then performed with a probe temperature of 373 K and a recycle delay of 15 s.

[0201] The 1H NMR spectrum for waste HDPE acquired from a waste jug is displayed inFIG.11.

[0202] The 1H NMR spectrum for waste PP acquired from a centrifuge tube is displayed inFIG.12.

[0203] The 1H NMR spectrum for waste LDPE acquired from food packaging is displayed inFIG.13.

[0204] The q 1H NMR spectrum for waste LDPE acquired from food packaging is displayedin FIG.14.

[0205] HT-SEC chromatograms for all examples of waste are displayed in FIG. 15.PATENT Attorney Docket No.: 052103-531001WO Quantification of Light Olefins by GC-FID

[0206] Quantification of light olefins present in the headspace of the Parr reactor wasconducted as follows.

[0207] Each reactor headspace was charged with approximately 10 bar of methane as aninternal standard, with the exact pressure of methane measured and recorded to 0.01 bar for each experiment as well as the temperature of the reactor headspace. The moles of methane present were then given by the van der Waals equation (S4). (1). (^^ +^^^^2^^2) (^^ − ^^^^) = ^^^^^^(S4), ^^^^^^4= 0.04278L / mol)

[0208] Using the van der Waals derivedof each light olefinformed with the following equation (S5). ^^ ^^^^^^^^^^^^^^=^^^^^^ℎ^^^^^^^^^^(S5)

[0209] Where Rf refers to theresponse of analyte to the methaneinternal standard at equal concentration. Rfwas calculated by preparing a series of mixtures of analyte and methane of known concentration and measuring three replicates of FID data on each mixture. The average ratio of the peak area of analyte to the peak area of methane was then plotted against the ratio of the concentration of analyte to the concentration of methane. Linear regression was then performed on this series, and the resulting slope was recorded as Rf. The results of this analysis for ethylene are summarized in Table 5, for propylene in Table 6, and for isobutylene in Table 7.PATENT Attorney Docket No.: 052103-531001WO Table 5. Rƒ Measurement Data for EthyleneTable 6. Rƒ Measurement Data for PropyleneTable 7. Rƒ Measurement Data for IsobutylenePATENT Attorney Docket No.: 052103-531001WO

[0210] With these coefficients determined, the final yield of propylene or isobutylene andconversion of ethylene for any given isomerizing ethenolysis reaction is thus given by the following equation (S6): (^^^^^^^^^^^^^^^^^^^^%^^^^^^^^^^ =^^)(4) ^^^^4^^^^ ∗ 100%(S6)in which Axrepresents theFID and nxrepresents the moles of a given species. For each GC-FID experiment, 30 μL of the headspace was injected manually and subjected to the following temperature profile: the column was held at an initial temperature of 30 °C for 5 min, after which the temperature was raised at a rate of 15 °C / min for 14.67 min. After a final temperature of 250 °C was reached, the temperature was held for an additional 10 min. The experiment was then terminated. The initial inlet pressure and temperature were set to 9.46 psi and 250 °C respectively, and the flow rate through the column was held constant at 2.22 mL / min. In all cases, the carrier gas was helium.

[0211] Reported selectivities for propylene and isobutylene against butenes (e.g. theselectivity of propylene against butenes, the selectivity of isobutylene against other butenes) were calculated according to: where s represents the selectivity, np(in moles) of product (i.e. propylene or isobutylene) and ∑(^^^^) represents the total yield (in moles) of all other butene isomers (i.e. 1-butene, cis- and trans-butene). Procedures for Isomerizing Ethenolysis of Isotopically Enriched Polyolefins Polyethylene Reaction Conditions

[0212] Within a nitrogen-filled glovebox, (natural abundance) high-density polyethylene(954.8 mg, 34.04 mmol) and polyethylene (13C2) (46.7 mg, 3.109 mmol) were combined in a flame-dried 100 mL beaker. To this mixture was added WO3 / SiO2 (400.0 mg, 0.110 mmol W, 0.0031 equiv.) and Na / γ-Al2O3 (400.0mg, 1.740 mmol Na, 0.0488 equiv.). The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and charged with 10.20 bar methanePATENT Attorney Docket No.: 052103-531001WO (120.9 mmol) and 15.36 bar ethylene at 26 °C. The reactor was then heated to 320 °C, with stirring initiated after The reaction was allowed to stir at 320 °C for 90 min, and the headspace was then sampled for analysis by GC-FID and GC-MS. Yield propylene: 63.88 mmol (89.75%). Polypropylene Reaction Conditions

[0213] Within a nitrogen-filled glovebox, (natural abundance) isotactic polypropylene (958.5mg, 22.78 mmol) and polypropylene (13C-1) (45.8 mg, 1.063 mmol) were combined in a flame- dried 100 mL beaker. To this mixture was added WO3 / SiO2 (400.0 mg, 0.110 mmol W, 0.0031 equiv.) and Na / γ-Al2O3 (400.0mg, 1.740 mmol Na, 0.0488 equiv.). The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and charged with 10.28 bar methane (121.9 mmol) and 15.01 bar ethylene at 26 °C. The reactor was then heated to 320 °C, with stirring initiated after the reactor reached 150 °C. The reaction was allowed to stir at 320 °C for 90 min, and the headspace was then sampled for analysis by GC-FID and GC-MS. Yield propylene: 30.14 mmol (126.4%). Evaluation of Isotopic Enrichment by GC-MS

[0214] For each of the preceding experiments, a low-resolution GC-MS spectrum (EI) wasobtained of the propylene product. The isotopic enrichment was obtained by the following procedure:

[0215] GC-MS (EI) spectra was obtained from natural abundance propylene produced fromthe PIE of HDPE (according to the above procedure) and the average intensities of each m / z peak from 40-43 were recorded. These peak intensities were then normalized such that the base peak (M-1, m / z = 41) had an intensity of 1. These normalized peak intensities are recorded in Table 7.

[0216] The intensity of the peak at m / z = 43 is assumed to originate entirely from the M+fragment of the13C-1 isotopomer of propylene. From high resolution spectra of propylene which we reported previously, the relative intensity of the M+, [M-1]+, [M-2]+, and [M-3]+ fragment peaks are known to be 0.740, 1.000, 0.318, and 0.668 respectively for both the12C3 and13C-1 isotopomers of propylene. Thus, the contribution of the13C-1 isotopomer to the intensity of the peaks at m / z 42-40 can be estimated from these values using the following equation (S7):PATENT Attorney Docket No.: 052103-531001WO where ^^13^^ corresponds to thefor a given peak, I43 corresponds to the intensity of the peak at m / z = 43, ^^[^^−^^]+ corresponds to the relative intensity of a given [M-N]+ peak (as noted above), and^^[^^]+ to the relative intensity of the[M]+ peak. So, for an m / z = 43 peak with a of 0.0085 for example, the contribution of the the13C-1 isotopomer to the peaks at m / z = 42, 41, and 40 would be 0.0115, 0.0028, and 0.0076 respectively. The calculated contributions of the13C-1 isotopomer to the intensity of the peaks at m / z = 42, 41, and 40 for all mass spectra from natural abundance propylene are displayed in Table 8. Table 8. Normalized EI-MS Peak Intensities for Natural Abundance Propylene

[0217] It is assumed that the total intensity of each peak in the mass spectrum is due to thecombined contributions of the 12C3 and 13C-1 isotopomers of propylene. From this assumption, it can be inferred that the contribution to the peak intensity at a given m / z is the differencebetween the total peak intensity I and ^^ ^^13 (S8):

[0218] The calculated to the intensity of the peaks atm / z = 42, 41, and 40 for all mass spectra of the propylene from the PIE of13C enriched polymers are displayed in Table 9.PATENT Attorney Docket No.: 052103-531001WO Table 9. Normalized EI-MS Peak Intensities for 13C-Enriched Propylene from 13C- Enriched PEcalculated, the intensity can be estimated as the ratio of the total peak intensity of the [M]+, [M- 1]+, and [M-2]+ fragments of the13C-1 isotopomer at m / z = 43, 42, 41 to the sum of the peak intensity of the [M]+, [M-1]+, and [M-2]+ fragments of the13C-1 isotopomer and the [M]+, [M- 1]+ and [M-2]+ fragments of the 12C3 isotopomer at m / z = 42, 41, and 40 respectively (S9):

[0220] Where [13C]1isotopomer. N represents anormalization factor equal to 2.476, calculated from the solution of S9 from the average of threePATENT Attorney Docket No.: 052103-531001WO mass spectra of propylene obtained from the PIE of unenriched HDPE where [13C] was assumed to be that of natural abundance propylene, i.e.3.321%.

[0221] Once enrichments are calculated from S9, yields of the 12C3 and 13C-1 isotopomersfrom each reaction were calculated using the following equation (S10).

[0222] With a similarisotopomer, where [12C] is simplythe difference between unity and [13C], and np represents the total yield of propylene from the PIE reaction, calculated as described above. Values of [13C] and np for each experiment are summarized in Table 10. Table 10. Calculated Enrichments for 13C-Enriched Propylene from PIE Procedures for the PIE of Polyolefins in a Semi-Batch Configuration Investigation of the Effect of Ethylene Pressure on Reaction Efficiency

[0223] Within a nitrogen-filled glovebox, polyethylene (1.000 g, 35.65 mmol), WO3 / SiO2(400.0 mg, 0.110 mmol W, 0.0031 equiv.), and Na / γ-Al2O3 (400.0mg, 1.740 mmol Na, 0.0488 equiv.) were combined in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and connected with Swagelok fittings to two Parker Porter model 210 mass flow controllers, supplied with 300psi of ethylene and methane selectively. The mass flow controllers were independently calibrated using a bubble flow meter. The flow rate of methan internal standard was set at 5 SCCM, and the flow rate of ethylene at the desired flow rate for the experiment. The inlet line was then charged to 3-4 bar with the gas mixture and was then evacuated to 100 mbar using an inline ball valve connected to a vacuum source. The line was then charged to 3-4 bar and evacuated to 100 mbar four more times to remove any oxygen and water impurities. The reactor was then opened to the gas flow using a needle valve andPATENT Attorney Docket No.: 052103-531001WO charged to the desired pressure before a needle valve was opened on the reactor outlet which was connected to a GC-FID fitted with an inlet sampling valve. The flow at the outlet was measured with an Agilent universal gas flow controller and adjusted to match the gas flow into the reactor. The outlet space was then sampled using the inlet valve, with subsequent samples taken every 12.00 minutes. The reactor was then heated at 320 °C for 180 min. Semi-Batch PIE of Polypropylene Under Optimized Pressure and Flow Conditions

[0224] Within a nitrogen-filled glovebox, polypropylene (1.000 g, 23.76 mmol), WO3 / SiO2(400.0 mg, 0.110 mmol W, 0.0046 equiv.), and Na / γ-Al2O3(400.0mg, 1.740 mmol Na, 0.0413 equiv.) were combined in a flame-dried 100 mL beaker. The beaker was then placed in a 300 mL Parr reactor. The reactor was sealed and connected with Swagelok fittings to two Parker Porter model 210 mass flow controllers, supplied with 300psi of ethylene and methane respectively. The flow rate of methane internal standard was set at 5 SCCM, and the flow rate of ethylene at 100 SCCM. The inlet line was then charged to 3-4 bar with the gas mixture and was then evacuated to 100 mbar using an inline ball valve connected to a vacuum source. The line was then charged to 3-4 bar and evacuated to 100 mbar four more times to remove any oxygen and water impurities. The reactor was then opened to the gas flow using a needle valve and charged to 19 bar (gauge pressure) before a needle valve was opened on the reactor outlet which was connected to a GC-FID fitted with an inlet sampling valve. The flow at the outlet was measured with an Agilent universal gas flow controller and adjusted to match the gas flow into the reactor. The outlet space was then sampled using the inlet valve, with subsequent samples taken every 12.00 minutes. The reactor was then heated at 320 °C for 180 min.

[0225] The GC method was adjusted from the method for batch reactors as follows: The GCoven was set to an initial temperature of 50 °C. The inlet was set to 225 °C, with a pressure of 10.087 psi and a total flow of 65 mL / min, a split flow of 60 mL / min, and a split ratio of 30 : 1. The flow through the column was held at a constant rate of 2.5 mL / min. At t = 0.01 min, the inlet valve was opened, and closed again at t = 0.5 min. At t = 1 min, the oven was heated to 68 °C at a rate of 8 °C / min, then immediately to 92 °C at a rate of 32 °C / min, then to 96 °C at a rate of 2 °C / min, then to 128 °C at a rate of 10 °C / min for an overall run time of 10 minutes.PATENT Attorney Docket No.: 052103-531001WO Calculation of Instantaneous Flow Rates and Cumulative Yield of Light Olefins in Semi- Batch

[0226] The instantaneous molar flow rates for each light olefin were calculated using thepeak areas of each GC chromatogram at a given timepoint and the calculated response factors from the section titled “Quantification of Light Olefins by GC-FID.” Given that the molar flow rate of methane is constant and known, the instantaneous molar flow rate for each light olefin is given by S11 as follows: where rx is the molar flow rate of athe peak area in the GC chromatogram for that light olefin, ICH4 is the peak area in the GC chromatogram for methane, Rf is the response factor for that light olefin, and rCH4is the volumetric flow rate of methane. From the instantaneous flow rates of each light olefin at each timepoint, the cumulative yield of a given light olefin at a given timepoint n is given using the trapezoidal rule (S12): where nx represents the, represents the molar flow rate of that olefin at a a particular timepoint ti (in mol / min), rx(ti+1) represents the instantaneous molar flow rate of that olefin at the the next timepoint ti+1, and tiand ti+1are given in minutes. Large Scale Demonstration of PIE in Semi-Batch

[0227] The PIE of 50 g of HDPE with isolation of the resulting products was conducted asfollows:

[0228] Within a nitrogen-filled glovebox, polyethylene (50.00 g, 1.783 mol), WO3 / SiO2(10.00 g, 2.750 mmol W, 0.0015 equiv.), and Na / γ-Al2O3 (10.00 g, 43.50 mmol Na, 0.0244 equiv.) were combined directly in the steel cylinder of a 300 mL Parr reactor. The reactor was sealed and connected to a regulator set to continuously deliver 19 bar (gauge pressure) of ethylene. The outlet was connected to approximately one meter of 0.25” Swagelok tubing bentPATENT Attorney Docket No.: 052103-531001WO into a coil with a turn diameter of approximately 5 cm. A 450 mL Parr reactor was connected to the end of this coil to condense heavy volatile components of the efflux at 20 °C. A Parker Porter model 21 mass flow controller was connected to the outlet of this reactor. An adjustable pressure relie valve (Swagelok series RL3) set to vent at 5 bar was connected to the outlet of the mass flow controller to prevent a pressure buildup. To the outlet of this valve was connected another coil of 0.25” Swagelok tubing with an approximate overall length of one meter and an average turn diameter of approximately 5 cm. This coil was cooled to -78 °C using a dry ice acetone bath. The outlet of this coil was connected to another 450 mL Parr reactor which was cooled to -94 °C using a bath of acetone and liquid nitrogen. The outlet of this reactor was connected to an oil bubbler and vented with atmosphere. A photograph of this setup is provided in FIG.16.

[0229] After assembly, the entire setup was purged of any oxygen or moisture by setting themass flow controller to deliver a flow of 1000 SCCM and opening the needle valve on the outlet of the 300 mL Parr reactor. This flow was allowed to purge the system for 15 minutes, after which the 300 mL Parr reactor was heated to 150 °C with stirring at 50 rpm. Once the contents of the reactor reached 150 °C, the stir rate was increased to 650 rpm and the reactor was heated at 320 °C. Once the contents of the reactor reached 320 °C, the reactor was allowed to stir under the same flow of ethylene for 3 h, at which point the inflow of ethylene was halted. The system was allowed to continue venting at 1000 SCCM until ambient pressure was achieved, at which point the 450 mL Parr reactor at 20 °C was sealed by closing needle valves at its inlet and outlet, and the 450 mL Parr reactor was removed from the -94 °C bath and disassembled. The contents of this reactor were then poured into a 250 mL graduated cylinder pre-cooled with liquid nitrogen. The volume of collected liquid was quickly measured, and then 5 mL of this mixture were returned to the 450 mL Parr reactor, which was sealed and allowed to warm to rt. The headspace of this reactor was then sampled and analyzed by GC-FID. The oil isolated at 20 °C was then weighed accurately and analyzed by 1H NMR and GC-FID. The 300 mL Parr reactor was then allowed to cool to room temperature and disassembled. The solid contents of the reactor were then weighed carefully to determine overall conversion.

[0230] For such large scale experiments, mass transport was found to be a critical factor inachieving appreciable yields. We therefore found it necessary to modify the turbine type impeller supplied by Parr Instrument Company as follows:PATENT Attorney Docket No.: 052103-531001WO

[0231] Four one inch sections of 0.25” Swagelok tubing were crimped flat such that they slideasily onto each of the blades of a turbine-type impeller supplied by Parr Instrument Company. Each tubing section was then crimped tightly onto each of the impeller blades using a bench vise until no gap was visible in the end of the tubing and the tubing could not be moved. The tubing sections were then filed until smooth. The modified turbine was then attached to the bottom of the impeller shaft, with an additional unmodified turbine attached approximately 3” higher on the impeller shaft to ensure efficient mixing of the gas headspace. A photograph of the modified impeller assembly is provided in FIG.17.

[0232] Yield (-94 °C): 90.0 mL

[0233] Yield (20 °C): 11.81 g

[0234] Solid mass remaining in reactor: 35.100 g (represents a conversion of 34.900 g ofHDPE, 69.8%)

[0235] The 1H NMR spectrum of the 20 °C oil fraction is displayed in FIG. 18.Calculation of the Yield of Propylene from the Large Scale Demonstration of PIE

[0236] The measured volume of condensate at -94 °C in this reaction was 90.0 mL. Thecomposition of this condensate was measured to be 76.1 % propylene, 21.1 % butenes, and trace quantities of methane, ethylene, and propane. The yield of propylene is thus given by S13: where nC3H6 represents the yield ofrepresents the total volume of condensate, XC3H6 represents the mole fraction of propylene in the condensate (i.e.0.761), p represents the density of the mixture (estimated to be that of liquid propylene at the boiling point, i.e.0.613 gmL-1), and 42.081 is the molecular weight of propylene. Therefore, the yield of propylene was calculated to be 1.00 mol (28.1%, 364 TON with respect to W).PATENT Attorney Docket No.: 052103-531001WO REFERENCES 1. R. Geyer, J. R. Jambeck, K. L. Law, Production, use, and fate of all plastics ever made. Science Advances 3, e1700782 (2017).2. G. W. Coates, Y. D. Y. L. Getzler, Chemical recycling to monomer for an ideal, circular polymer economy. Nature Reviews Materials 5, 501-516 (2020).3. A. Chamas et al., Degradation Rates of Plastics in the Environment. ACS Sustainable Chemistry & Engineering 8, 3494-3511 (2020).4. Q. Dong et al., Depolymerization of plastics by means of electrified spatiotemporal heating. Nature 616, 488-494 (2023).5. U. R. Gracida-Alvarez, O. Winjobi, J. C. Sacramento-Rivero, D. R. Shonnard, System Analyses of High-Value Chemicals and Fuels from a Waste High-Density Polyethylene Refinery. Part 1: Conceptual Design and Techno-Economic Assessment. ACS Sustainable Chemistry & Engineering 7, 18254-18266 (2019).6. N. Netsch et al., Chemical Recycling of Polyolefinic Waste to Light Olefins by Catalytic Pyrolysis. Chemie Ingenieur Technik 95, 1305-1313 (2023).7. Y. Wang et al., Catalytic Pyrolysis of Polyethylene for the Selective Production of Monocyclic Aromatics over the Zinc-Loaded ZSM-5 Catalyst. ACS Omega 7, 2752-2765(2022). 8. W. C. Edenfield et al., Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic / Cationic Organo-group IV Catalysts. ACS Catalysis 14,554-565 (2024). 9. J. E. Rorrer, G. T. Beckham, Y. Román-Leshkov, Conversion of Polyolefin Waste to Liquid Alkanes with Ru-Based Catalysts under Mild Conditions. JACS Au 1, 8-12 (2021).10. J. E. Rorrer, C. Troyano-Valls, G. T. Beckham, Y. Román-Leshkov, Hydrogenolysis of Polypropylene and Mixed Polyolefin Plastic Waste over Ru / C to Produce Liquid Alkanes. ACS Sustainable Chemistry & Engineering 9, 11661-11666 (2021).PATENT Attorney Docket No.: 052103-531001WO C. Wang et al., Polyethylene Hydrogenolysis at Mild Conditions over Ruthenium onTungstated Zirconia. JACS Au 1, 1422-1434 (2021).L. D. Ellis et al., Tandem Heterogeneous Catalysis for Polyethylene Depolymerizationvia an Olefin-Intermediate Process. ACS Sustainable Chemistry & Engineering 9, 623-628 (2021). X. Jia, C. Qin, T. Friedberger, Z. Guan, Z. Huang, Efficient and selective degradation ofpolyethylenes into liquid fuels and waxes under mild conditions. Science Advances 2,e1501591 (2016). D. Kim et al., Metathesis, molecular redistribution of alkanes, and the chemicalupgrading of low-density polyethylene. Applied Catalysis B: Environmental 318, 121873(2022). J. Sun et al., Bifunctional tandem catalytic upcycling of polyethylene to surfactant-rangealkylaromatics. Chem 9, 2318-2336 (2023).F. Zhang et al., Polyethylene upcycling to long-chain alkylaromatics by tandemhydrogenolysis / aromatization. Science 370, 437-441 (2020).R. J. Conk et al., Catalytic deconstruction of waste polyethylene with ethylene to formpropylene. Science 377, 1561-1566 (2022).N. M. Wang et al., Chemical Recycling of Polyethylene by Tandem Catalytic Conversionto Propylene. J. Am. Chem. Soc. 144, 18526-18531 (2022).Z. Chen, A. D. Sadow, B. Peters, A Microkinetic Model for Isomerizing Ethenolysis.ACS Catalysis 14, 6339-6348 (2024). D. Guironnet, B. Peters, Tandem Catalysts for Polyethylene Upcycling: A Simple KineticModel. The Journal of Physical Chemistry A 124, 3935-3942 (2020). V. Farkas, M. Nagyházi, P. T. Anastas, J. Klankermayer, R. Tuba, Making PersistentPlastics Degradable. ChemSusChem 16, e202300553 (2023). M. Nagyházi et al., Catalytic Decomposition of Long-Chain Olefins to Propylene viaIsomerization-Metathesis Using Latent Bicyclic (Alkyl)(Amino)Carbene-PATENT Attorney Docket No.: 052103-531001WO RutheniumOlefin Metathesis Catalysts. Angewandte Chemie International Edition 61, e20220441340 (2022). G. Novodárszki et al., Propylene synthesis via isomerization–metathesis of 1-hexene and FCC olefins. Catalysis Science & Technology 11, 6257-6270 (2021). R. L. Banks, Industrial aspects of the disproportionation reaction. Journal of MolecularCatalysis 8, 269-276 (1980). J. C. Mol, Industrial applications of olefin metathesis. Journal of Molecular Catalysis A:Chemical 213, 39-45 (2004).M. Monai, M. Gambino, S. Wannakao, B. M. Weckhuysen, Propane to olefins tandem catalysis: a selective route towards light olefins production. Chemical Society Reviews 50, 11503-11529 (2021). Alkenes: Recent Advances, New Perspectives and Applications. (IntechOpen, 2021). M. Bhasin, J. McCain, B. Vora, T. Imai, P. Pujado, Dehydrogenation andoxydehydrogenation of paraffins to olefins. Applied Catalysis A: General 221, 397-419(2001). K. Wang et al., Selective dehydrogenation of small and large molecules by a chloroiridium catalyst. Science Advances 8, eabo6586 (2022) Q. Wu, Acidic and basic catalytic cracking technologies and its development prospectsfor crude oil to chemicals. Fuel 332, 126132 (2023).K. J. Ivin, J. C. Mol, Olefin Metathesis and Metathesis Polymerization. (Elsevier Science, 1997). J. G. Howell, Y.-P. Li, A. T. Bell, Propene Metathesis over Supported Tungsten OxideCatalysts: A Study of Active Site Formation. ACS Catalysis 6, 7728-7738 (2016).F. M. A. Geilen, G. Stochniol, S. Peitz, E. Schulte-Koerne, in Ullmann’s Encyclopedia of Industrial Chemistry. pp.1-13.PATENT Attorney Docket No.: 052103-531001WO G. Santos, E. Esmizadeh, M. Riahinezhad, Recycling Construction, Renovation, and Demolition Plastic Waste: Review of the Status Quo, Challenges and Opportunities.Journal of Polymers and the Environment 32, 479-509 (2024).W. O. Haag, H. Pines, The Kinetics of Carbanion-catalyzed Isomerization of Butenesand 1-Pentene1-3. Journal of the American Chemical Society 82, 387-391 (1960).

Claims

PATENT Attorney Docket No.: 052103-531001WO WHAT IS CLAIMED IS:

1. A method of converting a polyethylene to propylene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the propylene; wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst.

2. A method of converting a polypropylene to a mixture of propylene and isobutylene, the method comprising contacting the polypropylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the mixture of propylene and isobutylene; wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst.

3. A method of converting a polyethylene to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene; wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst.

4. The method of any one of claims 1 to 3, wherein the method requires no prior dehydrogenation step.

5. The method of claim 2, wherein the propylene and the isobutylene are formed as a mixture that is less than 3:1 propylene to isobutylene.

6. The method of claim 5, wherein the yield of the mixture of propylene and isobutylene is greater than 50%.

7. The method of claim 6, wherein the yield of the mixture of propylene and isobutylene is greater than 60%.PATENT Attorney Docket No.: 052103-531001WO 8. The method of claim 7, wherein the yield of the mixture of propylene and isobutylene is greater than 70%.

9. The method of claim 8, wherein the yield of the mixture of propylene and isobutylene is greater than 80%.

10. The method of claim 4, wherein the method is performed at about 300oC to about 350oC.

11. The method of claim 10, wherein the method is performed at about 320oC.

12. The method of claim 3, wherein the residence time of the olefin metathesis catalyst and / or olefin isomerization catalyst is 30 min in a context of continuous ethylene feed setup.

13. The method of claim 3, wherein the residence time of the olefin metathesis catalyst and / or olefin isomerization catalyst is 5 min in a context of continuous ethylene feed setup.

14. The method of one of claims 1 to 3, wherein the olefin metathesis catalyst comprises the transition metal selected from W, Mo, Re, Ta, and Ru, and wherein the metal oxide solid support is selected from SiO2, mixed SiO2-Al2O3, gamma-phase Al2O3, Al2O3, TiO2, CeO2, MgO, ZrO2, MFI-type zeolite (MFI), and H-beta zeolite (HBEA).

15. The method of claim 14, wherein the transition metal is selected from W, Mo, Re, and wherein the metal oxide solid support is selected from SiO2, mixed SiO2-Al2O3, and gamma- phase Al2O3.

16. The method of claim 15, wherein the transition metal is W.

17. The method of claim 16, wherein the metal oxide solid support is SiO2.

18. The method of claim 17, wherein the olefin metathesis catalyst is WO3 / SiO2.

19. The method of one of claims 14-18, wherein the olefin metathesis catalyst does not comprise rhenium.

20. The method of one of claims 1-19, where the method does not comprise the use of rhenium.PATENT Attorney Docket No.: 052103-531001WO 21. The method of claims 14 or 15, wherein the amount of the transition metal per unit surface area of the metal oxide solid support is about 0.1 to about 2.5 atoms per nm2.

22. The method of claim 21, wherein the amount of the transition metal per unit surface area of the metal oxide solid support is 0.6 atoms per nm2.

23. The method of any one of claims 1 to 3, wherein the basic olefin isomerization catalyst comprises an alkali metal dispersed on a solid support.

24. The method of claim 23, wherein the alkali metal is selected from Na, K, Li, Na / K mixture, Rb, and Cs, and wherein the solid support is selected from SiO2, gamma-phase Al2O3, TiO2, CeO2, MgO, CaO, and an aluminosilicate zeolite.

25. The method of claim 24, wherein the alkali metal is selected from Na, K, Li, and Na / K mixture, and wherein the solid support is selected from SiO2and gamma-phase Al2O3.

26. The method of claim 23, wherein the basic olefin isomerization catalyst comprises an alkali metal oxide or alkali metal hydroxide.

27. The method of claim 26, wherein the alkali metal oxide or the alkali metal hydroxide is selected from MgO, CaO, Na2O, Li2O, and K2O.

28. The method of one of claims 23 to 27, wherein the alkali metal is about 2 to about 20 weight % of said basic olefin isomerization catalyst.

29. The method of one of claims 23 to 28, wherein the alkali metal is Na.

30. The method of one of claim 23 to 29, wherein the solid support is Al2O3.

31. The method of one of claim 23 to 30, wherein the solid support is gamma phase Al2O3.

32. The method of one of claim 23 to 31, wherein the basic olefin isomerization catalyst further comprises a transition metal.

33. The method of one of claim 23 to 32, wherein the basic olefin isomerization catalyst further comprises a Fe, Ga, V, Cr, Mn, Co, Zr, Pd, Ti and / or La.

34. The method of one of claim 23 to 33, wherein the basic olefin isomerization catalyst further comprises a MgO, ZrO2, TiO2, and La2O3.PATENT Attorney Docket No.: 052103-531001WO 35. The method of one of claim 23 to 32, wherein the basic olefin isomerization catalyst further comprises Fe at a concentration of 0.01-1.0%.

36. The method of one of claim 23 to 35, wherein the solid support does not comprise platinum.

37. The method of one of claims 1 to 35, wherein the method does not comprise the use of platinum.

38. The method of one of claims 1 to 3, wherein the acidic olefin isomerization catalyst is selected from a MFI-type zeolite (MFI), MEL-type zeolite (MEL), beta zeolite (BEA), MTF-type zeolite (MTF), chlorinated metal or metal oxide, fluorinated metal or metal oxide, and sulfated metal or metal oxide.

39. The method of claim 38, wherein the metal or the metal oxide is selected from chlorinated alumina, fluorinated alumina, and sulfated tantalum oxide.

40. The method of any one of claims 1 to 3, wherein the transition metal olefin isomerization catalyst comprises a metal, a metal oxide, a metal hydroxide or mixtures thereof, or a metal on a solid support.

41. The method of claim 40, wherein the metal, the metal oxide, the metal hydroxide or mixtures thereof, or the metal on solid support is selected from Pd, Ir, Ru, Fe, Co, Rh, Os, and Pt.

42. The method of claim 41, wherein the solid support is selected from SiO2, mixed SiO2-Al2O3, gamma-phase Al2O3,Al2O3, TiO2, CeO2, MgO, ZrO2, MFI-type zeolite (MFI), and beta zeolite (BEA).

43. The method of one of claims 1 to 42, further comprising, after said forming the propylene, contacting the olefin isomerization catalyst with dimethyl ether thereby regenerating said olefin isomerization catalyst.

44. The method of claim 43, wherein the dimethyl ether is present in a gas.

45. The method of claim 44, wherein the gas is a gas stream.

46. The method of claim 44 or 45, wherein the gas is a helium gas.PATENT Attorney Docket No.: 052103-531001WO 47. The method of claim 46, wherein the dimethyl ether is present at a concentration of about 5%.

48. The method of claim 47, wherein a regeneration temperature is about 450oC.

49. A method of converting a mixture of polyethylene and polypropylene to a mixture of propylene and isobutylene, the method comprising contacting the polyethylene and polypropylene mixture with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the mixture of propylene and isobutylene; wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst.

50. A method of converting a polyethylene, a polypropylene, or a mixture of the two to a C3 to C30 alkene, the method comprising contacting the polyethylene with ethylene, an olefin metathesis catalyst and an olefin isomerization catalyst, thereby forming the C3 to C30 alkene; wherein the olefin metathesis catalyst comprises a transition metal attached to a metal oxide solid support and the olefin isomerization catalyst is a basic olefin isomerization catalyst, an acidic olefin isomerization catalyst or a transition metal olefin isomerization catalyst.

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