Upgrading cycle of polyethylene and polypropylene and mixtures thereof to high value surfactants

Abstract

Provided herein is a method of using a coolant fluid (e.g., water) to adjust the condensation temperature of the end product to control the molar mass of the thermal decomposition product. By this strategy, the thermal decomposition of polyethylene (PE) and polypropylene (PP) can be tailored to produce liquid oils without any catalyst or additive. Sulfuric acid is subsequently added to the alkenyl group and then neutralized with sodium hydroxide, providing a sulfate detergent having excellent foaming behavior.

Description

Cross-reference to related applications

[0001] This application claims priority and interest in co-pending U.S. provisional application filed April 28, 2023, with serial number 63 / 462,863, entitled “UPCYCLING OF POLYETHYLENE AND POLYPROYLENE AND THEIR MIXTURES TO HIGH-VALUE SURFACTANTS”, the contents of which are incorporated herein by reference. Statement regarding federally funded research or development

[0002] This invention was completed with government funding under project DMR1752611 granted by the National Science Foundation. The government has certain rights in this invention. Technical Field

[0003] This disclosure generally relates to the manufacture of ionic detergents / surfactants and diesel fuels, and particularly to the manufacture of alkyl sulfates based on polyethylene and polypropylene, which exhibit excellent foaming properties and are therefore suitable for cleaning purposes, industrial processes, or as inexpensive fuels after hydrogenation. background

[0004] Plastic waste accumulation is a major environmental challenge facing the planet. Globally, 380 million tons of plastic are generated annually, and nearly 75% of it is disposed of after a single use. [1] In particular, polyethylene (PE) and polypropylene (PP) account for 60% of all plastics and constitute the majority of discarded waste. [2-3] In order to meaningfully reverse the trend of plastic waste accumulation and minimize carbon emissions, it is crucial to increase recycling rates and extend the lifespan of materials in accordance with the Kyoto Protocol and the Paris Agreement. [4] Traditional recycling strategies (i.e., mechanical recycling) help close the plastic cycle, but the quality of recycled plastics inevitably deteriorates, and their market value decreases. After multiple cycles, plastics reach the end of their service life. End-of-life plastics offer a highly attractive alternative to traditional methods as inexpensive raw materials for producing value-added chemicals.

[0005] In this context, converting plastics such as PE and PP into liquid fuels and other high-value chemicals is an attractive strategy. [5-6] Typically, pyrolyzing polyolefins into oils requires elevated temperatures and long reaction times. [7]Pyrolysis oil typically undergoes further hydrotreating to hydrogenate unsaturated hydrocarbons. [8-9] Furthermore, it improves fuel quality. Because pyrolysis oil is a complex mixture with a wide range of boiling points, it is fractionated into hydrocarbons ranging from naphtha to diesel to provide specific transport fuel grades.

[10] In the pyrolysis of polyolefins, it is still necessary to control the selectivity of oils and waxes, in other words, to control the hydrocarbon product distribution (HPD). Overview of this disclosure

[0006] In several respects, this disclosure provides methods for preparing fatty acids. The methods for preparing fatty acids described in this disclosure overcome many shortcomings of existing methods for preparing fatty acids, such as the methods described herein using underutilized resources to generate high-value detergents and ionic detergents. This work highlights a feasible chemical strategy for obtaining essential high-value products from plastic waste while contributing to the goals of a circular economy. Furthermore, the fatty acids produced by the methods described herein open up opportunities for alternative fuel applications.

[0007] In some aspects, the techniques described herein relate to methods for preparing waxes and / or oils from olefin-derived products, the method comprising: heating a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof in a container in fluid communication with a condenser to provide a mixture of sublimated waxes and / or oils collected on a condenser or thermal control system, wherein the heating comprises raising the temperature of the container to a target temperature for a first time period and maintaining the container at or near the target temperature for a second time period to provide the mixture of waxes and / or oils.

[0008] In some aspects, the techniques described herein relate to a method in which raising the temperature of a container comprises heating at a rate of about 10°C to about 30°C per minute during a first time period.

[0009] In some respects, the technique described herein relates to a method in which the second time period is 1 hour to 48 hours, 1 hour to 24 hours, 1 hour to 20 hours, or 5 hours to 20 hours.

[0010] In some aspects, the techniques described herein relate to a method in which raising the temperature of a container involves heating the bottom of the container to a target temperature in three steps at a increment of about 80°C to about 120°C every 5 minutes.

[0011] In some aspects, the techniques described herein relate to a method for preparing a mixture of waxes and / or a mixture of oils, the method comprising introducing a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof into a continuous flow reaction vessel in fluid communication with a condenser or heating control system to provide a mixture of sublimated waxes and / or a mixture of oils collected on the condenser or heating control system, wherein the continuous flow reaction vessel is at or near a target temperature, and wherein the polymer has a residence time in the continuous flow reaction vessel to provide the mixture of waxes and / or a mixture of oils.

[0012] In some respects, the techniques described herein relate to a method in which the dwell time is 1 hour to 48 hours, 1 hour to 24 hours, 1 hour to 20 hours, or 5 hours to 20 hours.

[0013] In some respects, the techniques described herein relate to a method in which the target temperature is approximately 250°C to 500°C.

[0014] In some aspects, the techniques described herein relate to a method in which the target temperature is 260°C to 490°C, 270°C to 480°C, 290°C to 460°C, 310°C to 440°C, 330°C to 420°C, 350°C to 400°C, or 370°C to 380°C.

[0015] In some respects, the techniques described herein relate to a method in which the target temperature is approximately 320°C to 350°C.

[0016] In some aspects, the techniques described herein relate to a method in which the target temperature is 320°C to 400°C, or 340°C to 380°C, or 320°C to 370°C, or 330°C to 360°C.

[0017] In some respects, the techniques described herein relate to a method in which a polymer is exposed to ambient air.

[0018] In some aspects, the techniques described herein relate to a method in which a polymer is exposed to an inert gas in a container.

[0019] In some respects, the techniques described herein involve a method in which the inert gas is nitrogen or argon.

[0020] In some aspects, the techniques described herein relate to a method in which a polymer is exposed to oxygen mixed with an inert gas in a container.

[0021] In some aspects, the techniques described herein relate to a method in which a polymer is exposed to air mixed with an inert gas in a container.

[0022] In some respects, the techniques described herein relate to a method in which a container is heated at atmospheric pressure.

[0023] In some aspects, the techniques described herein relate to a method in which the polymer is selected from the group consisting of cross-linked polypropylene, cross-linked polyethylene, linear polypropylene, linear polyethylene, and combinations thereof.

[0024] In some aspects, the techniques described herein relate to a method in which the polymer is selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polyethylene copolymers, polypropylene copolymers, and high-density cross-linked polyethylene.

[0025] In some aspects, the techniques described herein relate to a method in which the percentage mass conversion of a polymer to a mixture of waxes is about 85% to 99%, or about 85% to 95%, or about 85% to 90%, or about 90% to 95%.

[0026] In some aspects, the techniques described herein relate to a method in which the temperature difference between the surfaces of the container and the condenser is about 300°C to 400°C or about 325°C to 375°C.

[0027] In some respects, the techniques described herein relate to a method in which the target temperature is approximately -195°C to 250°C.

[0028] In some aspects, the technology described herein relates to a method in which a condenser surface has temperatures ranging from -185°C to 240°C, -175°C to 230°C, -165°C to 220°C, -155°C to 210°C, -145°C to 200°C, -135°C to 190°C, -125°C to 180°C, -115°C to 170°C, -105°C to 160°C, -95°C to 150°C, -85°C to 140°C, -75°C to 130°C, -65°C to 120°C, -55°C to 110°C, -45°C to 100°C, -35°C to 90°C, -25°C to 80°C, -15°C to 70°C, -5°C to 60°C, 5°C to 50°C, 15°C to 40°C, and 25°C to 30°C.

[0029] In some respects, the techniques described herein relate to a method in which a container, condenser, or both includes a quartz surface.

[0030] In some aspects, the techniques described herein relate to a method in which, based on the total weight of the mixture of waxes and / or the mixture of oils, the wt% of light hydrocarbons having eight or fewer carbon atoms in the mixture of waxes and / or the mixture of oils is about 10 wt%, 8 wt%, 5 wt%, or less.

[0031] In some aspects, the techniques described herein relate to a method in which the method further includes adding sulfuric acid to a mixture of waxes and / or a mixture of oils.

[0032] In some aspects, the techniques described herein relate to a method in which a mixture of waxes and / or a mixture of oils independently have hydrocarbon lengths of C7-C26 and are acyclic, cyclic, or a combination thereof.

[0033] In some aspects, the techniques described herein relate to a method in which a mixture of waxes and / or a mixture of oils is independently an unsaturated hydrocarbon, a saturated hydrocarbon, or a combination thereof.

[0034] In some respects, the techniques described herein involve a method that also includes neutralization.

[0035] In some respects, the techniques described herein relate to a method in which neutralization includes the addition of sodium hydroxide or potassium hydroxide.

[0036] In some aspects, the techniques described herein relate to a method in which a condenser includes a liquid circulation, optionally wherein the liquid is water, glycol, mineral oil, dielectric fluid, or a combination thereof.

[0037] In some respects, the techniques described herein relate to a method in which waxes and / or oils are further hydrogenated or borohydrinated.

[0038] In some aspects, the techniques described herein relate to a method that further includes blending a mixture of fatty acids with an alkali to provide a mixture of fatty acid carboxylates.

[0039] In some aspects, the techniques described herein relate to a method that further includes treating a mixture of fatty acid carboxylates with acid to provide a purified mixture of fatty acids.

[0040] In some aspects, the techniques described herein relate to a method in which alkyl manganese carboxylate is added to a mixture of waxes and / or a mixture of oils.

[0041] In some respects, the techniques described herein relate to a method in which manganese alkylcarboxylate is manganese stearate.

[0042] In some aspects, the techniques described herein relate to a method in which the alkyl carboxylate is selected from the group consisting of C12-C24-alkyl carboxylates and combinations thereof.

[0043] In some aspects, the techniques described herein relate to a method in which a mixture of waxes and / or a mixture of oils comprises waxes with an average carbon chain length of about C18 to C47, and a mixture of fatty acids comprises fatty acids with an average carbon chain length of about C18 to C47, or both.

[0044] In some aspects, the techniques described herein relate to a method in which the w / w ratio of a mixture of manganese alkylcarboxylate and wax is from about 0.001 to about 0.10.

[0045] Other systems, methods, features, and advantages for preparing fatty acids will be apparent to or will become apparent to those skilled in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within the scope of this disclosure and protected by the appended claims. Brief description of the attached diagram

[0046] Other aspects of this disclosure will be readily understood when viewed in conjunction with the accompanying drawings and after reviewing the detailed description below. The components in the drawings are not necessarily to scale, but rather the emphasis is on clearly illustrating the principles of this disclosure. Furthermore, in the drawings, the same reference numerals indicate corresponding parts throughout the various views.

[0047] Figure 1A- Figure 1D This is a schematic diagram of the process for upcycling PE and PP into fatty acids in a temperature gradient reactor. (Figure 1A) A custom-designed gradient thermal reactor is used to separate and upcycle commercial polyolefins, including high-density PE (HDPE), low-density PE (LDPE), high-density crosslinked PE (XLPE), and PP, into soap products. The temperature gradient reactor has hot and cold zones to prevent complete thermal decomposition of PE and PP into smaller molecules and is key to controlling the chain length of fragmented products. Photographs show representative PE and PP waste used in this study, as well as the final products of soap and surfactant solutions. (Figure 1B) Reaction scheme for upcycling PE and PP into fatty acids. (Figure 1C) Product distribution after PE degradation in reactors with and without temperature gradients. Distribution and abundance were measured by GC. Signals 3 through 7 overlap with toluene solvent and are therefore not shown for clarity. (Inset) Infrared thermal images of reactors with and without temperature gradients. Figure 1D The acid values ​​of the obtained fatty acids were compared with the theoretical values ​​of stearic acid (SA, C18) and fatty acids with average carbon numbers of PE C47 and PP C46.

[0048] Figure 2A- Figure 2DThe process involves the degradation of PE into intermediate waxes and subsequent recycling to fatty acids. The yields (Fig. 2A) and GC-MS chromatograms (Fig. 2B) of the intermediate waxes after PE degradation in N2, 10% O2 in N2 equilibrium, and air are shown. (Fig. 2C) NMR-HMBC spectrum of PE-N2-wax in deuterated p-xylene; (c inset) Chemical structure of the major olefin product. Circles highlight the CH correlation of the major and minor olefin products, respectively. The minor olefin shows a weak signal on the NMR-HMBC of PE-O-wax. Figure 11B However, due to overlap with the solvent, only a weak correlation was found in (Figure 2C). Figure 2D NMR-HMBC spectra of fatty acids derived from PE-O-wax. The black boxes highlight the correlation between the two carboxyl carbons and the protons.

[0049] Figure 3A- Figure 3D The degradation of PP and PE / PP mixtures into intermediate waxes and their subsequent recycling into fatty acids. (Figure 3A) Yields of intermediate waxes from PP degradation in N2, N2 / O2 mixtures with 10 vol% O2, and air. (Figure 3B) Wax yields from degradation of mixtures of HDPE (25 wt.%), PP (25 wt.%), LDPE (25 wt.%), and XLPE (25 wt.%). Acid values ​​of the polymer mixtures are shown in Table 4. (Figure 3C) NMR-HMBC of PP-N2-wax in deuterated p-xylene (c inset, chemical structure of the major olefin product). Circles highlight the CH correlation of the major and minor olefin products, respectively. Minor olefins in Figure 17A The signal is shown in (c), but due to overlap with deuterated p-xylene solvent, only a weak correlation is found in (c). Figure 3D NMR-HMBC of PP-air-FA; inset, chemical structure of the major fatty acid product. The black box highlights the correlation between the three carboxyl carbons and the proton.

[0050] Figure 4 This describes the reactor design and PE / PP degradation procedure. (Left) Design of the quartz reactor. Fluorinated rubber components are used to minimize the potential degradation of the O-rings and diaphragm, and to reduce the absorption of gaseous products. (Right) Stepwise procedure for PE / PP degradation: Step 1, Loading polymer waste; Step 2, Purge the reactor with gas while heating the bottom and supplying cooling water; Step 3, Heating the bottom of the reactor stepwise to 360°C (~100°C / 5 min); Stop purging and cover the gas outlet as soon as the polymer begins to "smoke"; Step 4, Provide a cooling airflow to keep the cover at a low temperature.

[0051] Figure 5A- Figure 5B This is (Figure 5A) the infrared thermogram of the reactor when the bottom is heated to ~360°C. Figure 5B Photograph of the reactor during PE / PP degradation. The degraded wax appears as "smoke," which scatters the red laser beam and shows a faint red trail.

[0052] Figure 6 This is GC-MS of gaseous products from PE degradation. Chemicals with a probability match of <70% are not shown. The total amount of gaseous products is <10 wt.%.

[0053] Figure 7 This is GC-MS of wax products derived from PE degradation. The inset shows the m / z of the corresponding molecular ions.

[0054] Figure 8 This is an enlarged view of the chromatogram in Figure 2B. Compared with PE-N2-wax, the chromatograms of PE-O-wax and PE-air-wax did not show significant peak shifts or new signals.

[0055] Figure 9A- Figure 9C This is a characterization of PE and PP waxes and their fatty acids. (Figure 9A) GC-FID chromatograms of PP degradation products in air, 10 vol% O2 in N2 equilibrium, and N2. (Figure 9B) HT-GPC chromatograms of the polymer, its degradation products in 10 vol% O2, air, and N2, and the derived fatty acids. Figure 9C APCI-MS spectra of PE-N2-wax, PE-O-wax, and PE-O-FA (left), PP-N2-wax, PP-air-wax, and PP-air-FA (right). Molecular weights were calculated based on the spectra using Equation S2. Note that the calculated molecular weights may be lower than the actual molecular weights due to fragmentation during MS analysis. The results are listed in Table 3.

[0056] Figures 10A-10B This is the NMR spectrum of PE-N2-wax. Figure 10A NMR-HMBC spectrum of PE-N2-wax in deuterated p-xylene (same as Figure 2C) and magnified view showing the major and minor alkenyl signals, as highlighted by circles. Figure 10B ) Magnified view of the HSQC spectrum and alkenyl signal of PE-N2-wax. It was observed that carbons carrying an even number of hydrogens (CH2) are typically high-field compared to carbons carrying an odd number (CH, CH3) of hydrogens, which are typically low-field (e.g., compared to H). b Compared to H a ).

[0057] Figures 11A-11B This is the NMR spectrum of PE-O-wax. Figure 11AHMBC spectrum of PE-O-wax, and magnified views of alkenyl and carbonyl signals. Alkenyl and carbonyl signals are highlighted with circles and squares, respectively. Figure 11B ) Magnified view of the HSQC spectrum and alkenyl signal of PE-O-wax. It was observed that carbons carrying an even number of hydrogens (CH2) are typically high-field compared to carbons carrying an odd number (CH, CH3) of hydrogens, which are typically low-field (e.g., compared to H... b Compared to H a ).

[0058] Figures 12A-12E It is the FTIR of waxes derived from PE and PP. Figure 12A (Top) PE-N2-wax and (bottom) PP-N2-wax oxidation on manganese stearate over time. Figure 12B (Top) Time evolution of oxidation of PE-O-wax and (bottom) PP-air-wax on manganese stearate, and FTIR spectra of the resulting fatty acids from PE-O-FA and PP-air-FA. (Figure 12C) Time evolution of carbonyl index (CI) of PE and PP-derived waxes. CI is defined as the ratio of carbonyl to CH signal in the FTIR. (Figure 12D) FTIR spectra of MnO2 catalyst (black) and PE-N2-wax before (red) and after (blue) oxidation with MnO2. Figure 12E FTIR spectrum of standard stearic acid (CI=0.78).

[0059] Figure 13 This is the NMR HMBC after PE-O-wax was oxidized on manganese stearate for 6 h. Magnified views of the alkenyl and carbonyl signals are highlighted by solid circles and squares, respectively.

[0060] Figure 14 This is the NMR HMBC of a fatty acid derived from PE-O-wax. The magnified view highlights the alkenyl signal (circle) and acid signal (box). The inset shows the possible fatty acid structure.

[0061] Figure 15 This is GC-MS of gaseous products from PP degradation. Chemicals with a probability below 70% are not shown. The total amount of gaseous products is <10 wt.%.

[0062] Figure 16 This is GC-MS of wax products derived from PP degradation. The inset shows the m / z of the molecular ions.

[0063] Figures 17A-17B This is the 2D NMR spectrum of PP-N2-wax. Figure 17ANMR HMBC spectrum of PP-N2-wax with amplified alkenyl signals. The unsaturated carbon signals δ111-112 include several correlations with protons. Minor C 13 -Proton correlation (C 13 NMR, δ 111.3-111.8, H 1 NMR (δ 4.68, 4.89 and ~2.2) and main C 13 -Proton correlation (C 13 NMR, δ111-112, H 1 NMR (δ 1.7) indicates the overlap of terminal olefin signals. Figure 17B NMR HSQC spectra showed a strong correlation with protons, indicating that 2-methyl-2-propenyl is the dominant form of the terminal olefin.

[0064] Figures 18A-18B This is the NMR spectrum of PP-air-wax. Figure 18A NMR HMBC spectrum of PP-air-wax, magnified view showing alkenyl signals (circles) and carbonyl signals (boxes). Figure 18B The NMR HSQC spectrum of PP-air-wax, magnified view showing the alkenyl signal, reveals only one strong correlation with the proton, similar to PP-N2-wax. The HMBC and HSQC spectra of PP-air-wax and PP-N2-wax indicate a dominant 2-methyl-2-propenyl structure in the terminal olefin.

[0065] Figure 19 This is NMR HMBC of PP-air-wax oxidized for 2 h. The magnified view highlights the alkenyl signal (circle) and carbonyl signal (box).

[0066] Figure 20 This is the NMR HMBC of fatty acids derived from PP-air-wax. The magnified view highlights the alkenyl signal (circle) and acid signal (box).

[0067] Figure 21 This is the time evolution of olefin concentration after oxidation. Data points are listed in Table 5. PP-derived waxes show higher olefin concentrations than PE-derived waxes. Oxygen significantly reduced the initial olefin concentrations in both PE-air-wax and PP-air-wax.

[0068] Figure 22 It represents the temperature-dependent olefin yield from the thermal decomposition of PE (black cubes) and PP (gray cubes) in a fluidized bed reactor. 12-19 Compared to the olefin yield of this work.

[0069] Figure 23A- Figure 23EThis controls the distribution of hydrocarbon products from the thermal decomposition of plastics. (Figure 23A) Various plastic wastes used in the degradation experiment. (Figure 23B) IR camera photograph showing the temperature of the condensation zone in the reactor. (Figure 23C) PE-wax and PE-oil produced after thermal decomposition via circulating cold water and hot water, respectively. (Figure 23D) GC traces of PE-oil and PE-wax produced under the two sets of conditions. Figure 23E As of 2023, the market prices of virgin plastics, raw materials chemicals and materials used, and upgraded recycled products.

[0070] Figure 24A- Figure 24D The molar masses of hydrocarbon products from the thermal decomposition of PP and mixed PE / PP were adjusted. (Figure 24A) Analysis and quantification of various product phases generated in the thermal decomposition reactions of PE, PP, and PE / PP mixtures (mixing ratio = 75 wt.% PE and 25 wt.% PP). Circulating hot water was used to supply 51 wt.%, 62 wt.%, and 54 wt.% of the thermal decomposition oils from PE, PP, and PE / PP mixtures, respectively, via the reactor. Figure 24B The distribution of cycloalkanes and acyclic products in PE, PP, and PE / PP thermal decomposition oils revealed high concentrations of acyclic olefins and alkanes suitable for downstream detergent applications. (Figure 24C) and ( Figure 24D GC traces of oil and wax products from PP and PE / PP mixtures under different reaction conditions. The carbon number distribution shifts to lower values ​​after circulating water at 90°C. All hydrocarbons observed in PP-oil-90°C are ≤C20.

[0071] Figures 25A-25C It involves upgrading and recycling PE and PP thermal decomposition oils into sulfate detergents. Figure 25A Scheme for sulfation of olefin oils and subsequent neutralization into ionic detergents. (Figure 25B) Sulphation of HDPE oils in CDCl3. 1 H NMR. (e.g., via H NMR.) 1 As demonstrated by HNMR, all terminal olefin groups reacted completely. Figure 25C HSQC NMR of HDPE-oleyl alkyl hydrogen sulfate in CDCl3 highlights the correlation with the sulfation reaction.

[0072] Figure 26A- Figure 26C This describes the determination of the wettability of PE-detergent, PP-detergent, and PE / PP-detergent. (Figure 26A) Illustration of the substrate used for contact angle measurement. Photograph of detergent droplets on a glass substrate covered with a paraffin film. Figure 26B In all cases, the contact angle decreases with increasing detergent concentration. Figure 26CContact angle as the concentration of PE-detergent, PP-detergent, and PE / PP-detergent varies.

[0073] Figures 27A-27D These are the physicochemical properties of sulfate detergents. Figure 27A Foam stability of HDPE, PP, and mixed PE / PP derived detergents. HDPE-detergents exhibited higher foam stability than PP-detergents and PE / PP-detergents. (Figure 27B) Emulsifying ability of detergents was obtained by recording the time required to separate 10 ml of water from a paraffin oil-water mixture. (Figure 27C) Figure 27D ) Surface tension relative to (Figure 27C) PE-detergent concentration and ( Figure 27D A graph of PE / PP detergent concentration is used to determine CMC.

[0074] Figure 28 It is a selective upgrade cycle of PE and PP derived oils to primary alkyl sulfates.

[0075] Figure 29 It is an olefin oil treated with sulfuric acid and neutralized with dilute sodium hydroxide solution, which exhibits excellent foaming properties. Furthermore, the upgraded cycle mixture of HDPE and PP wax demonstrates good foaming behavior at room temperature.

[0076] Figure 30A- Figure 30B This section describes the determination of alkenyl group concentrations in the thermal decomposition products of PE. (Figure 30A) mmol / g alkenyl group concentrations in PE-oil and PE-wax. The higher alkenyl group concentration in the oil is attributed to the longer duration of degradation products in the reaction zone. Figure 30B C6D6 1 1H NMR highlights the olefin peaks used to estimate concentration.

[0077] Figure 31 This is a structural analysis of the gas phase of HDPE thermal decomposition. Figure 31 Chromatograms and GC-MS of the gaseous products. The gas phase may contain some liquid fraction hydrocarbons with sufficiently high vapor pressures, such as hexane and heptane. Thermal decomposition products decompose into acyclic and cyclic hydrocarbons; the figure shows that acyclic hydrocarbons dominate in the PE product stream.

[0078] Figure 32 This describes the behavior of vaporized hydrocarbons under two different thermal decomposition conditions. At T2 = 28°C, the vaporized hydrocarbons (typically in the wax range) solidify on the reactor wall because the wall temperature is below the melting point of the wax (mp range of PE = 68.8°C–80.1°C). Conversely, when T2 = 90°C, the vaporized products liquefy and flow back to the bottom of the reactor for further chain breaking.

[0079] Figure 33 This is molecular weight characterization. Experiments were run at 160 °C in 1,3,5-trichlorobenzene. A GPC chromatogram of the wax product was produced at T2 = 28 °C. Similarly, experiments were conducted using a high-temperature GPC with 1,3,5-trichlorobenzene flowing at 50 °C. A GPC chromatogram of the oil was produced at T2 = 90 °C. Experiments were performed at ambient temperature on a lignin-GPC with flowing THF.

[0080] Figure 34 This is a structural analysis of the gas phase from the thermal decomposition of PP. Chromatograms and GC-MS of the gas phase products are shown. The increased intensity of compound 12 is likely due to the high vapor pressure of the same product detected in the liquid fraction.

[0081] Figure 35 This is a structural analysis of PP oil. C6D6 1 The 1H NMR spectrum highlights the olefin peaks between 4.5 ppm and 5.0 ppm. Notably, the olefin groups show predominantly terminal olefins, as no significant resonance peaks were detected outside the 5.0 ppm region where internal olefin groups are expected.

[0082] Figure 36 This is GC-MS of PP oil products. The product stream mainly contains non-cyclic methyl-substituted alkanes and alkenes. Cyclic hydrocarbons account for only ~15.3% of the PP thermal decomposition oil.

[0083] Figure 37 This is a structural analysis of the gas phase from the thermal decomposition of a plastic mixture. The chromatogram and GC-MS of the gas phase products are shown. The gas phase is dominated by ≤C6 olefins and alkanes, while cyclic hydrocarbons constitute only a small portion of the products.

[0084] Figure 38 This is a GC-MS analysis of a mixed oil product (75% PE and 25% PP). The oil fraction is characterized primarily by straight-chain olefins and alkanes, with a small amount of C. 11 To C 14 Diene compounds in the region. Additionally, methyl-substituted hydrocarbons produced by the decomposition of PP were detected 12 minutes prior.

[0085] Figure 39A- Figure 39B This involves determining the alkenyl group concentration in the thermal decomposition products of mixed plastics. (Figure 39A) C6D6 1 1H NMR highlights the olefin peaks used to estimate concentration and assess the ratio of terminal olefins to internal olefins. Figure 39B ) The mmol / g alkenyl concentration of mixed oils and mixed waxes.

[0086] Figure 40A- Figure 40BThis refers to the wetting properties of the mixed detergent under low PP loading. (Figure 40A) Contact angle on a hydrophobic surface as a function of concentration. Figure 40B Photographs of detergent droplets at different concentrations, overlaid with contact angle values. Overall, the wetting ability of this detergent formulation is comparable to that of pure PE-derived detergents.

[0087] Figure 41 This is the emulsification of paraffin oil and water by detergent. Left) 40 ml paraffin oil and 40 ml PE detergent solution before shaking. Middle) Mixture of the two components after shaking. c) 10 ml detergent solution separated from the homogenized mixture; the separation time of the 10 ml detergent solution is expressed as the emulsification time.

[0088] Figure 42 This study investigated the emulsifying properties of detergents based on plastic waste. Compared to a control experiment without detergent, a detergent solution (1.2 mL) mixed with 50 μL of hexane resulted in a significant reduction in the dispersed phase particle size.

[0089] Figure 43A- Figure 53B shows the surface tension properties of detergents containing PP products. Methyl-substituted products from PP degradation are associated with poor micellization at low detergent concentrations and have negligible effect on surface tension (Figure 43A). However, detergent formulations containing up to 10 wt.% PP products... Figure 43B It still exhibits good detergency comparable to PE-derived detergent solutions.

[0090] Figure 44A- Figure 44B This is the purification process following the sulfation reaction after post-treatment. (Figure 44A) Gas chromatogram of oil from plastic waste before sulfation. Each carbon number signal is characterized by olefin and alkane peaks; minor dienes were detected within specific carbon number ranges. Figure 44B Chromatogram of the hexane extract of the unreacted fraction of the oil. Only a single peak was observed for each carbon number signal, and it was confirmed as an alkane by GC-MS.

[0091] Figure 45 GC and GC-MS of unreacted extracts from HDPE oil.

[0092] Figure 46 GC and GC-MS of unreacted extracts from PP oil.

[0093] Figure 47 GC and GC-MS of unreacted extracts from a blend of oils (75 wt.% PE, 25 wt.% PP). Detailed Explanation

[0094] As the two most widely used commercial plastics, polyethylene (PE) and polypropylene (PP) together account for nearly 60% (~400 MT) of the world's plastic production, mainly for short-term applications. 1 Therefore, the manufacture of PE and PP is associated with the highest energy consumption of all plastics and contributes significantly to annual greenhouse gas emissions. 2 Short-term plastics quickly become waste and cause serious pollution. 3 In order to recycle PE and PP, the waste collection and sorting process must be economically efficient to reduce costs. 4 Ideally, the recycled products should be of high value to generate profit and have a large market capacity to impact plastic waste reduction. While PE and PP can be separated from heavier-than-water polymers such as polyvinyl chloride (PVC) and polyethylene terephthalate (PET) using a sink-float method with water as the medium (Figure 1A), further separation of PE and PP is more challenging due to their similar structure and density. Worse still, the two polymers are incompatible and cannot be blended without the use of expensive and complex compatibilizers. 5 Therefore, there is an urgent need for a universal and profitable method that can recycle both PE and PP while increasing the value of the final product compared to the virgin plastic. 3, 6-8 This paper describes a gradient-temperature pyrolysis method that can selectively break down both PE and PP into smaller alkyl chains. The temperature gradient in the reactor quenches the vaporized wax and prevents further degradation into smaller molecules. The method described in this paper transforms health- and environmentally relevant polyolefin waste into bio and environmentally beneficial chemicals.

[0095] Although any methods and materials similar to or equivalent to those described herein may be used in the practice or testing of this disclosure, preferred methods and materials are described hereafter. For the sake of brevity and / or clarity, functions or constructions well known in the art may not be described in detail. Unless otherwise indicated, aspects of this disclosure will employ techniques within the technical scope of the art, such as chemistry (e.g., polymer chemistry), materials science, and engineering. Such techniques are well explained in the literature.

[0096] It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed herein in range format. It should be understood that such range format is used for convenience and brevity, and therefore should be interpreted flexibly to include not only the numerical values ​​explicitly stated as limits of the range, but also all individual numerical values ​​or subranges covered within that range, as each numerical value and subrange is explicitly stated. For example, the numerical range “about 0.1% to about 5%” should be interpreted to include not only the explicitly stated value of about 0.1% to about 5%, but also individual values ​​(e.g., 1%, 2%, 3%, and 4%) and subranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range. Where a stated range includes one or both limits, ranges excluding any one or both of those included limits are also included in this disclosure; for example, the phrase “x to y” includes a range from 'x' to 'y' as well as ranges greater than 'x' and ranges less than 'y'. Ranges can also be expressed in upper limits, such as 'about x, y, z or less', and should be interpreted as including the specific ranges of 'about x', 'about y', and 'about z', as well as the ranges of 'less than x', 'less than y', and 'less than z'. Similarly, the phrase 'about x, y, z or greater' should be interpreted as including the specific ranges of 'about x', 'about y', and 'about z', as well as the ranges of 'greater than x', 'greater than y', and 'greater than z'. In some respects, the term "about" may include conventional rounding based on the significant figures of a numerical value. Furthermore, where 'x' and 'y' are numerical values, the phrase "about 'x' to 'y'" includes "about 'x' to about 'y'".

[0097] This disclosure has been organized using various section headings for convenience and readability, and should not be construed in any way as limiting the scope of this disclosure or the claims. In some cases, claims may incorporate aspects falling under different section headings, and combinations of these aspects are to be understood as being covered by this disclosure.

[0098] This disclosure will be better understood with the aid of certain definitions and prescribed methods, which are described in detail in the section entitled Definitions and Methods. Other terms and methods may be described elsewhere in this disclosure (including in the embodiments), and will be understood by those skilled in the art upon reading the disclosure provided herein. All definitions and methods described herein should be understood to take precedence over dictionary definitions, definitions in referenced literature, and / or the ordinary meaning of the defined terms.

[0099] Methods for preparing fatty acids In several aspects, this disclosure provides a method for preparing fatty acids, the method comprising: heating a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof in a container in fluid communication with a condenser to provide a mixture of sublimated wax collected on the condenser, wherein the heating comprises raising the temperature of the container to a target temperature for a first time period and maintaining the container at or near the target temperature for a second time period to provide the mixture of fatty acids.

[0100] In several aspects, this disclosure provides a method for preparing fatty acids, the method comprising: introducing a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof into a continuous flow reaction vessel in fluid communication with a condenser to provide a mixture of sublimated wax collected on the condenser, wherein the continuous flow reaction vessel is at or near a target temperature, and wherein the polymer has a residence time in the continuous flow reaction vessel to provide a mixture of fatty acids.

[0101] polypropylene and polyethylene In some aspects, polypropylene, polyethylene, or combinations thereof are introduced / placed / inserted into a container for heating. Polypropylene (PP), a polymer of propylene monomers, can include: atactic polypropylene (aPP) defined by an arrangement of random methyl groups (CH3); isotactic polypropylene (iPP) defined by methyl groups (CH3) arranged on one side of the carbon chain; and / or syndiotactic polypropylene (sPP) defined by an alternating arrangement of methyl groups (CH3). PP can be a homopolymer or a copolymer. In some aspects, PP can be an impact copolymer, foamed PP, PP terpolymer, or a combination thereof. In some aspects, PP can be a film, such as cast PP film (CPP) or biaxially oriented PP film (BOPP). In some aspects, PP is any one or more combinations of the PP discussed herein.

[0102] Polyethylene (PE), a polymer of ethylene (or ethylene) monomers, can include branched, linear, cross-linked, or combined forms of polyethylene. Branched forms can include low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE). Linear forms can include high-density polyethylene (HDPE) or ultra-high molecular weight polyethylene (UHMWPE). Cross-linked polyethylene can include PEX or XLPE. PE can include medium-density polyethylene (MDPE), ultra-low-density polyethylene (ULDPE), high molecular weight polyethylene (HMWPE), metallocene polyethylene (mPE), chlorinated polyethylene (CPE), or combinations thereof. In some aspects, PE is any one or more combinations of the PEs discussed herein.

[0103] container The container may include any shape, construction material, and size for implementing the methods described herein. For example, the container may be square, rectangular, spherical, or cylindrical. For example, the container size may vary depending on the amount of PP and / or PE to be converted and / or the amount of fatty acids to be produced. The container may be constructed of any one or more materials, including but not limited to: stainless steel; nickel-based alloys; carbon steel; refractory materials (e.g., ceramics); low-alloy steel; titanium alloys; tantalum; zirconium; composite materials; cladding materials; quartz; or combinations thereof. Refractory materials may include, for example, alumina and silicon carbide.

[0104] Container temperature In some aspects, the temperature of the container includes heating at a rate of about 10°C to about 30°C per minute during a first time period. In some embodiments, the temperature of the container includes heating at a rate of about 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, or 30°C per minute during the first time period, or heating at a rate within any range of any two listed temperatures per minute during the first time period. In some aspects, raising the temperature of the container includes heating the bottom of the container to the target temperature in three steps at a increment of about 80°C to about 120°C every 5 minutes. In some aspects, raising the temperature of the container involves heating the bottom of the container to the target temperature in three steps at intervals of approximately 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, 96°C, 97°C, 98°C, 99°C, 100°C, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C, 109°C, 110°C, 111°C, 112°C, 113°C, 114°C, 115°C, 116°C, 117°C, 118°C, 119°C, and 120°C every 5 minutes, or heating the bottom of the container to the target temperature in three steps at intervals of any range between any two of the listed temperatures every 5 minutes.

[0105] In some cases, the target temperature is approximately 250°C to 500°C. In some aspects, the target temperature is approximately 250℃, 251℃, 252℃, 253℃, 254℃, 255℃, 256℃, 257℃, 258℃, 259℃, 260℃, 261℃, 262℃, 263℃, 264℃, 265℃, 266℃, 267℃, 268℃, 269℃, 270℃, 271℃, 272℃, 273℃, 274℃, 275℃, 276℃, 277℃, 278℃, 279℃, 280℃, 281℃, 282℃, 283℃, 284℃, 285℃, 286℃, 287℃, 288℃, 289℃, 290℃, 291℃, 292℃, 293℃, 294℃, 295℃, 2 96℃, 297℃, 298℃, 299℃, 300℃, 301℃, 302℃, 303℃, 304℃, 305℃, 306℃, 307℃, 308℃, 309℃, 310℃, 311℃, 312℃, 313℃, 314℃, 315℃, 316℃, 317℃, 318℃, 319℃, 320℃ ℃, 321℃, 322℃, 323℃, 324℃, 325℃, 326℃, 327℃, 328℃, 329℃, 330℃, 331℃, 332℃, 333℃, 334℃, 335℃, 336℃, 337℃, 338℃, 339℃, 340℃, 341℃, 342℃, 343℃, 344℃, 3 45℃, 346℃, 347℃, 348℃, 349℃, 350℃, 351℃, 352℃, 353℃, 354℃, 355℃, 356℃, 357℃, 358℃, 359℃, 360℃, 361℃, 362℃, 363℃, 364℃, 365℃, 366℃, 367℃, 368℃, 369℃, 370℃, 371℃, 372℃, 373℃, 374℃, 375℃, 376℃, 377℃, 378℃, 379℃, 380℃, 381℃, 382℃, 383℃, 384℃, 385℃, 386℃, 387℃, 388℃, 389℃, 390℃, 391℃, 392℃, 393℃ 394℃, 395℃, 396℃, 397℃, 398℃, 399℃, 400℃, 401℃, 402℃, 403℃, 404℃, 405℃, 406℃, 407℃, 408℃, 409℃, 410℃, 411℃, 412℃, 413℃, 414℃, 415℃, 416℃, 417℃, 41 8℃, 419℃, 420℃, 421℃, 422℃, 423℃, 424℃, 425℃, 426℃, 427℃, 428℃, 429℃, 430℃, 431℃, 432℃, 433℃, 434℃, 435℃, 436℃, 437℃, 438℃, 439℃, 440℃, 441℃, 442℃443℃, 444℃, 445℃, 446℃, 447℃, 448℃, 449℃, 450℃, 451℃, 452℃, 453℃, 454℃, 455℃, 456℃, 457℃, 458℃, 459℃, 460℃, 461℃, 462℃, 463℃, 464℃, 465℃, 466℃, 467℃, 468℃, 469℃, 470℃, 471℃, 472℃, 473℃ 474℃, 475℃, 476℃, 477℃, 478℃, 479℃, 480℃, 481℃, 482℃, 483℃, 484℃, 485℃, 486℃, 487℃, 488℃, 489℃, 490℃, 491℃, 492℃, 493℃, 494℃, 495℃, 496℃, 497℃, 498℃, 499℃, 500℃, or any range between any two listed temperatures. In some aspects, the target temperature is 260℃ to 490℃, 270℃ to 480℃, 290℃ to 460℃, 310℃ to 440℃, 330℃ to 420℃, 350℃ to 400℃, or 370℃ to 380℃. In some aspects, the target temperature is approximately 320℃ to 350℃. In some cases, the target temperature is 320°C to 400°C, or 340°C to 380°C, or 320°C to 370°C, or 330°C to 360°C.

[0106] In some aspects, the vessel includes a thermal control system. The thermal control system may include one or more components. For example, the thermal control system may include: one or more temperature sensors; one or more sensor-transmitters; one or more controllers; one or more control elements; one or more heat exchangers; one or more reactor jackets; or any combination thereof. Temperature sensors may include thermocouples. Control elements may include, for example, control valves and / or electric heaters. In some aspects, the vessel and / or thermal control system includes a safety instrumented system.

[0107] Duration of stay In some aspects, the polymer has a residence time in a continuous flow reaction vessel to provide a mixture of fatty acids. The residence time can include the time the polymer is in or in contact with the vessel before being converted into a mixture of fatty acids, the amount of time required to convert a desired amount of polymer into a mixture of fatty acids, or the desired length of time for carrying out the method. The residence time can vary depending on the material to be heated (i.e., PP, PE, or a combination thereof). In some aspects, the residence time is 1 to 48 hours, 1 to 24 hours, 1 to 20 hours, or 5 to 20 hours. In some respects, the length of stay is approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, or 72 hours.

[0108] Condenser In some aspects, the container is in fluid communication with a condenser to provide a mixture of sublimated wax collected on the condenser. In some aspects, the condenser is in fluid communication with the container to collect the mixture of sublimated wax. In some aspects, the container is jacketed with a condenser. The jacket allows liquid to circulate around the container. As an example, the fluid communication between the condensers of the jacketed container may include a first opening near a first end of the condenser attached to or otherwise connected to the container and a second opening near a second end of the condenser, the condenser including a fluid passage providing fluid communication to the container, and the mixture of sublimated wax collected in the container through the condenser. The jacketed container may be single-configured or double-configured. In a double configuration, the outer jacket may be vacuum-insulated, while the inner jacket provides liquid circulation. In some aspects, the condenser is jacketed around the container. The condenser may jacket the entire wall of the container or a portion thereof. For example, the condenser can jacket any amount between 90%, 80%, 75%, 70%, 66%, 60%, 50%, 40%, 33%, 30%, 25%, 20%, 10%, or 99% and 1% of the container. The condenser jacket can provide a temperature gradient within the container. For example, the condenser can provide a region or zone within the container that is cooler than the heated area or zone of the container. As an example, the bottom of the container is heated to a desired temperature while the condenser in the jacket above the bottom of the container cools a portion of the container above the bottom to a desired temperature lower than the bottom temperature. A mixture of waxes can be collected in the container. For example, the mixture of waxes can be collected along the wall of the container, which is in liquid communication with the condenser of the jacketed container, so that the mixture of waxes is collected through the condenser.

[0109] As an example, fluid communication may be a first opening near a first end of a condenser attached to or otherwise connected to a container and a second opening near a second end of a condenser attached to or otherwise connected to a chamber for collecting a mixture of sublimated waxes, the condenser including a fluid passage providing fluid communication between the container and the chamber for collecting the mixture of sublimated waxes. The chamber for collecting the mixture of sublimated waxes may be a separate container or part of a condenser. In some aspects, the condenser may include Liebig, West, Allihn, Davies, Graham, coil condensers, Dimroth, Friedrichs, cold end probes, shell and tube condensers, brazed plates, coaxial sleeves, or variations thereof.

[0110] In some aspects, the condenser includes liquid circulation. For example, liquid circulation includes introducing liquid into the condenser to absorb heat from a container in fluid communication with the condenser. The heated liquid is removed from the condenser, thereby removing heat from the container. In some aspects, the liquid is discarded and new liquid is introduced into the condenser. In some aspects, the liquid is removed from the condenser, cooled, and then reintroduced into the condenser.

[0111] In some aspects, the liquid is water, glycol, mineral oil, dielectric fluid, or a combination thereof. The liquid used for the condenser can be selected based on desired cooling properties. For example, the liquid can be selected based on the desired temperature difference between the heating section of the container and the cooling section of the container or condenser. Alternatively, the liquid can be selected based on the desired temperature of the cooling section of the container or condenser. As an example, the liquid can be selected by its operating temperature range, allowing different liquids to correspond to different temperatures. As an example, the liquid can be selected by its thermal conductivity. In some aspects, the condenser temperature is from approximately -195°C to 250°C. In some aspects, the surface temperature of the condenser is -185°C to 240°C, -175°C to 230°C, -165°C to 220°C, -155°C to 210°C, -145°C to 200°C, -135°C to 190°C, -125°C to 180°C, -115°C to 170°C, -105°C to 160°C, -95°C to 150°C, -85°C to 140°C, -75°C to 130°C, -65°C to 120°C, -55°C to 110°C, -45°C to 100°C, -35°C to 90°C, -25°C to 80°C, -15°C to 70°C, -5°C to 60°C, 5°C to 50°C, 15°C to 40°C, and 25°C to 30°C. In some aspects, the condenser temperature is approximately -195℃, -190℃, -185℃, -180℃, -175℃, -170℃, -165℃, -160℃, -155℃, -150℃, -145℃, -140℃, -135℃, -130℃, -125℃, -120℃, -115℃, -110℃, -105℃, -100℃, -95℃, -90℃, -85℃, -80℃, -75℃, -70℃, -65℃, -60℃, -55℃, -50℃, -45℃, -40℃, -35℃, -30℃, -25℃, -20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 1 5℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, or 250℃, or any range between any two listed temperatures.

[0112] Temperature gradient In some aspects, a temperature gradient exists. A temperature gradient can exist between a container and a condenser. For example, the bottom of the container is heated, while the top of the container is cooled by the condenser. In some aspects, two (2) temperature gradients exist. In some aspects, 2, 3, 4, 5, 6, 7, 8, 9, or 10 temperature gradients exist. A temperature gradient between any two locations includes the temperature change between a first desired temperature and a second desired temperature. In some aspects, the temperature difference between the container temperature and the condenser temperature is approximately 700°C, 675°C, 650°C, 625°C, 600°C, 575°C, 550°C, 525°C, 500°C, 475°C, 450°C, 425°C, 400°C, 375°C, 350°C, 325°C, 300°C, 275°C, 250°C, 225°C, 200°C, 175°C, 150°C, 125°C, 100°C, 75°C, 50°C, 25°C, or any combination thereof. In some aspects, the temperature difference between the container and condenser surfaces is approximately 300°C to 400°C or approximately 325°C to 375°C.

[0113] fatty acids, waxes and oils In some aspects, the methods described herein provide for the preparation of waxes, oils, fatty acids, or combinations thereof. Waxes produced by the methods described herein comprise hydrocarbons obtained from heating PP and PE. These wax hydrocarbons may contain about 20 to 50 carbon atoms and may be saturated or unsaturated, and may be cyclic or acyclic. Oils produced by the methods described herein comprise hydrocarbons obtained from heating PP and PE. These oil hydrocarbons may contain about 5 to 26 carbon atoms and may be saturated or unsaturated, and may be cyclic or acyclic. Fatty acids produced by the methods described herein comprise hydrocarbons obtained from heating PP and PE. These fatty acids are compositions that may include carboxylic acid hydrocarbons and may contain about 7 to 30 carbon atoms and may be saturated or unsaturated, and may be cyclic or acyclic. In some aspects, mixtures of waxes and / or mixtures of oils comprise waxes with an average carbon chain length of about C42 to C47, wherein mixtures of fatty acids comprise fatty acids with an average carbon chain length of about C42 to C47, or both. In some respects, the waxes and / or oils produced by the methods described herein are oxidized into fatty acids.

[0114] borohydride In some aspects, the methods described herein also include hydroboration, which produces organoborane compounds. The hydrobores produced by the methods described herein can react with a variety of reagents to produce compounds such as alcohols, amines, sulfates, or alkyl halides. Exemplary reagents for hydroboration may include boranes (BH3), BH3·THF, B2H6, BH3·OEt2, BH3·dimethyl sulfide, and substituted boranes such as di-sec-pentylborane and 9-BBN. For example, the hydrobores can be further oxidized using hydrogen peroxide to produce alcohols.

[0115] Alkyl sulfates In some respects, fatty acids, waxes, oils, or combinations thereof undergo sulfation to produce alkyl sulfates. Sulfation may include reacting the fatty acids, waxes, oils, or combinations thereof with sulfuric acid or sulfur trioxide. Sulfation may also include first oxidizing the fatty acids, waxes, oils, or combinations thereof, and then reacting the oxidized fatty acids, waxes, oils, or combinations thereof with chlorosulfuric acid or sulfur trioxide. The alkyl sulfates may be saturated or unsaturated, and may be cyclic or acyclic.

[0116] neutralization In some aspects, the methods described herein also include neutralization. In some aspects, the sulfation reaction is neutralized. For example, neutralization of a sulfation reaction may include introducing a suitable base into the reaction mixture to neutralize polar sulfate or sulfonate groups with a counterion. Exemplary counterions include Na+. + K + NH4 + Ca 2+ Mg 2+ Zn 2+ Or an alkanolamine cation. Exemplary bases providing counterions include sodium hydroxide or potassium hydroxide.

[0117] hydrogenation In some aspects, the methods described herein also include hydrogenation for reducing or saturating unsaturated hydrocarbons produced by the methods described herein. For example, reducing or saturating an unsaturated hydrocarbon may include adding one or more pairs of hydrogen atoms, reducing or saturating an unsaturated double bond to a single bond, and / or reducing or saturating an unsaturated triple bond to a double or single bond. Typically, hydrogenation involves an unsaturated substrate (i.e., the hydrocarbon produced by the methods described herein), hydrogen (or a hydrogen source), and a catalyst. Hydrogenation can be carried out at various temperatures and pressures, selected based on the activity of the substrate and the catalyst. Hydrogen sources may include H2 gas, formic acid, isopropanol, and anthracene dihydrogenate. Catalysts may be homogeneous or heterogeneous. Catalysts may include platinum, palladium, rhodium, ruthenium, iridium, and nickel. For example, catalysts may include: trichlorotriphenylphosphine ruthenium(II), crabtree catalysts, cyclooctadiene rhodium chloride dimer, (S)-iPr-PHOX, Wilkinson catalysts, Lindlar catalysts, and Raney nickel.

[0118] Carboxylate In some aspects, the methods described herein produce alkyl carboxylates. In some aspects, the alkyl carboxylates are selected from the group consisting of C12-C24-alkyl carboxylates and combinations thereof. For example, waxes, oils, fatty acids, or combinations thereof produced by the methods described herein undergo carboxylation. In some aspects, manganese alkyl carboxylate is added to a mixture of waxes, oils, fatty acids, or combinations thereof produced by the methods described herein. The carboxylates produced by the methods described herein may contain about 5 to 47 carbon atoms and may be saturated or unsaturated, and may be cyclic or acyclic.

[0119] Inert gas / ambient air In some aspects, the polymer, wax, oil, fatty acid, or combination thereof is exposed to ambient air or an inert gas within the container. The inert gas may, for example, include nitrogen or argon. In some aspects, the polymer is a wax, oil, fatty acid, or combination thereof exposed to oxygen mixed with an inert gas within the container, or the polymer is a wax, oil, fatty acid, or combination thereof exposed to air mixed with an inert gas within the container.

[0120] definition Unless otherwise defined, all technical and scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will also be understood that, unless expressly defined herein, terms such as those defined in commonly used dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of this disclosure and in the relevant field, and shall not be interpreted in an idealized or overly formal sense.

[0121] The articles “a” and “an” as used herein, when applied to any feature of the aspects of the invention described in the specification and claims, mean one or more. The use of “a” and “an” does not limit the meaning to a single feature unless such limitation is specifically stated. The article “the” preceding a singular or plural noun or noun phrase indicates one or more specific features and may have a singular or plural connotation depending on the context in which it is used.

[0122] As used herein, the nomenclature of compounds (including organic compounds) may be provided using common names, IUPAC, IUBMB, or CAS recommendations for nomenclature. When one or more stereochemical features are present, the Cahn-Ingold-Prelog rule of stereochemistry can be used to indicate stereochemical priority, E / Z specification, etc. Those skilled in the art can readily determine the structure of a compound if its structure is systematically simplified using nomenclature conventions, or if a name is given using commercially available software such as CHEMDRAW™ (Cambridgesoft Corporation, USA).

[0123] Halogens can be F, Cl, Br, or I; or F, Cl, or Br; or F or Cl; or F; or Cl. Alkyl halides can typically be lower alkyl halides, or C1-C6 alkyl halides, or C1-C3 alkyl halides. Examples of C1-C3 alkyl halides include CH2F, CHF2, CF3, CH2Cl, CHCl2, CCl3, CF2CF3, CF2CF2H, and CH2CF3. The term "substituted" means that the alkyl or aryl group can be substituted by one to five substituents, which are fluorine, chlorine, bromine, iodine, C1-12 haloalkyl, nitro, C1-12 alkyl, C5-12 aryl or C1-12 alkoxy, cyano, C1-12 haloalkoxy, C1-12 alkylsulfenyl, C1-12 alkylsulfinyl, C1-12 alkylsulfonyl, C1-12 haloalkylsulfenyl, C1-12 haloalkyl The substituted group may be sulfinyl or C1-12 haloalkylsulfonyl, hydroxyl, thiol, amino, oxo, carboxyl, carbonylalkyl, C1-12 acylamino, C1-12 alkoxy-carbonylamino, C1-12 haloalkoxycarbonylamino, C1-12 alkoxyimino, C1-12 haloalkoxyimino or C1-12 alkylsulfonylamino or sulfur pentafluoride; such substitution may be fluorine, chlorine, bromine, C1-6 haloalkyl, C1-6 haloalkoxy, oxo, carboxyl, carbonylalkyl and cyano.

[0124] The term "leaving group" is understood by those skilled in the art to mean halides, such as fluorides, chlorides, bromides, iodides, alkyl sulfonates, such as methanesulfonates and trifluoromethanesulfonates, aryl sulfonates, such as p-toluenesulfonates, hydroxides, alkoxides, aryl oxides, carboxylates, such as acetates, ammonia, alkylamines, etc. Such leaving groups include conjugate acids of the aforementioned leaving groups.

[0125] As used herein, the terms “about,” “approximate,” “at or about,” and “generally” mean that the quantity or value discussed may be an exact value or a value that provides an equivalent result or effect to that described in the claims or taught herein. That is, it should be understood that quantities, dimensions, formulations, parameters, and other quantities and characteristics are not precise and need not be precise, but may be approximate and / or larger or smaller as desired, reflecting tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art, resulting in an equivalent result or effect. In some cases, the value providing an equivalent result or effect cannot be reasonably determined. In such cases, it is generally understood that, as used herein, “about” and “at or about” mean a variation of ±10% of the indicated nominal value, unless otherwise indicated or inferred. Generally, quantities, dimensions, formulations, parameters, or other quantities or characteristics are “about,” “approximate,” or “at or about,” whether or not explicitly stated otherwise. It should be understood that when “about,” “approximately,” or “in or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless otherwise specifically stated. Aspects of this disclosure

[0126] This disclosure will be better understood after reading the following numbered aspects, which should not be confused with the claims. In some cases, the following aspects may be combined with one or more other aspects or with other aspects described elsewhere in this disclosure and the accompanying examples. All such variations and combinations are intended to be covered by this disclosure.

[0127] Aspect 1. A method for preparing waxes and / or oils, comprising: heating a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof in a container in fluid communication with a condenser to provide a mixture of sublimated waxes and / or oils collected on the condenser, wherein the heating comprises raising the temperature of the container to a target temperature for a first time period and maintaining the container at or near the target temperature for a second time period to provide the mixture of waxes and / or oils.

[0128] Aspect 2. The method according to any one of Aspects 1-40, wherein raising the temperature of the container comprises heating at a rate of about 10°C to about 30°C per minute during a first time period.

[0129] Aspect 3. The method according to any one of Aspects 1-40, wherein the first time period is about 5 minutes to about 60 minutes, about 5 minutes to about 15 minutes, or about 10 minutes to about 30 minutes.

[0130] Aspect 4. The method according to any one of Aspects 1-40, wherein the second time period is 1 hour to 48 hours, 1 hour to 24 hours, 1 hour to 20 hours, or 5 hours to 20 hours.

[0131] Aspect 5. The method according to any one of Aspects 1-40, wherein raising the temperature of the container comprises heating the bottom of the container to the target temperature in three steps at a increment of about 80°C to about 120°C every 5 minutes.

[0132] Aspect 6. A method for preparing fatty acids, comprising: introducing a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof into a continuous flow reaction vessel in fluid communication with a condenser to provide a mixture of sublimated waxes and / or oils collected on the condenser, wherein the continuous flow reaction vessel is at or near a target temperature, and wherein the polymer has a residence time in the continuous flow reaction vessel to provide the mixture of waxes and / or oils.

[0133] Aspect 7. The method according to any one of Aspects 1-40, wherein the dwell time is 1 hour to 48 hours, 1 hour to 24 hours, 1 hour to 20 hours or 5 hours to 20 hours.

[0134] Aspect 8. The method according to any one of Aspects 1-40, wherein the target temperature is about 250°C to 500°C.

[0135] Aspect 9. The method according to any one of Aspects 1-40, wherein the target temperature is 260°C to 490°C, 270°C to 480°C, 290°C to 460°C, 310°C to 440°C, 330°C to 420°C, 350°C to 400°C, or 370°C to 380°C.

[0136] Aspect 10. The method according to any one of Aspects 1-40, wherein the target temperature is about 320°C to 350°C.

[0137] Aspect 11. The method according to any one of Aspects 1-40, wherein the target temperature is 320°C to 400°C, or 340°C to 380°C, or 320°C to 370°C, or 330°C to 360°C.

[0138] Aspect 12. The method according to any one of Aspects 1-40, wherein the polymer is exposed to ambient air.

[0139] Aspect 13. The method according to any one of Aspects 1-40, wherein the polymer is exposed to an inert gas in a container.

[0140] Aspect 14. The method according to any one of Aspects 1-40, wherein the inert gas is nitrogen or argon.

[0141] Aspect 15. The method according to any one of Aspects 1-40, wherein the polymer is exposed to oxygen mixed with an inert gas in a container.

[0142] Aspect 16. The method according to any one of Aspects 1-40, wherein the polymer is exposed to air mixed with an inert gas in a container.

[0143] Aspect 17. The method according to any one of Aspects 1-40, wherein the container is heated at atmospheric pressure.

[0144] Aspect 18. The method according to any one of Aspects 1-40, wherein the polymer is selected from the group consisting of cross-linked polypropylene, cross-linked polyethylene, linear polypropylene, linear polyethylene, and combinations thereof.

[0145] Aspect 19. The method according to any one of Aspects 1-40, wherein the polymer is selected from the group consisting of high-density polyethylene, low-density polyethylene and high-density cross-linked polyethylene.

[0146] Aspect 20. The method according to any one of Aspects 1-40, wherein the w / w ratio of the mixture of alkylcarboxylic acid manganese and wax is from about 0.001 to about 0.10.

[0147] Aspect 21. The method according to any one of aspects 1-40 further includes blending the mixture of fatty acids with a base to provide a mixture of fatty acid carboxylates.

[0148] Aspect 22. The method according to any one of aspects 1-40 further includes treating the mixture of fatty acid carboxylates with acid to provide a purified mixture of fatty acids.

[0149] Aspect 23. The method according to any one of Aspects 1-40, wherein the percentage mass conversion of the polymer to the wax mixture is about 85% to 99%, or about 85% to 95%, or about 85% to 90%, or about 90% to 95%.

[0150] Aspect 24. The method according to any one of Aspects 1-40, wherein the temperature difference between the container and the condenser surface is about 300°C to 400°C or about 325°C to 375°C.

[0151] Aspect 25. The method according to any one of Aspects 1-40, wherein the target temperature is about -195°C to 250°C.

[0152] Aspect 26. The method according to any one of Aspects 1-40, wherein the temperature of the condenser surface is -185°C to 240°C, -175°C to 230°C, -165°C to 220°C, -155°C to 210°C, -145°C to 200°C, -135°C to 190°C, -125°C to 180°C, -115°C to 170°C, -105°C to 160°C, -95°C to 150°C, -85°C to 140°C, -75°C to 130°C, -65°C to 120°C, -55°C to 110°C, -45°C to 100°C, -35°C to 90°C, -25°C to 80°C, -15°C to 70°C, -5°C to 60°C, 5°C to 50°C, 15°C to 40°C, or 25°C to 30°C.

[0153] Aspect 27. The method according to any one of Aspects 1-40, wherein the condenser comprises a quartz surface.

[0154] Aspect 28. The method according to any one of Aspects 1-40, wherein, based on the total weight of the mixture of waxes and / or the mixture of oils, the wt% of light hydrocarbons having eight or fewer carbon atoms in the mixture of waxes and / or the mixture of oils is about 10 wt%, 8 wt%, 5 wt%, or less.

[0155] Aspect 29. The method according to any one of Aspects 1-40, wherein the method further comprises adding sulfuric acid to the mixture of waxes and / or the mixture of oils.

[0156] Aspect 30. The method according to any one of Aspects 1-40, wherein the mixture of fatty acids is a mixture of alkyl sulfates.

[0157] Aspect 31. The method according to any one of Aspects 1-40, wherein the mixture of waxes and / or the mixture of oils independently have hydrocarbon lengths of C7-C26 and are acyclic, cyclic, or a combination thereof.

[0158] Aspect 32. The method according to any one of Aspects 1-40, wherein the mixture of waxes and / or the mixture of oils are independently unsaturated hydrocarbons, saturated hydrocarbons, or combinations thereof.

[0159] Aspect 33. The method according to any one of aspects 1-40, wherein the method further comprises neutralization.

[0160] Aspect 34. The method according to any one of Aspects 1-40, wherein neutralization comprises adding sodium hydroxide or potassium hydroxide.

[0161] Aspect 35. The method according to any one of Aspects 1-40, wherein the condenser includes a liquid circulation, optionally wherein the liquid is water, glycol, mineral oil, dielectric fluid or a combination thereof.

[0162] Aspect 36. The method according to any one of Aspects 1-40, wherein the wax and / or oil are further hydrogenated or borohydride-treated.

[0163] Aspect 37. The method according to any one of Aspects 1-40, wherein alkyl carboxylic acid manganese is added to the mixture of fatty acids.

[0164] Aspect 38. The method according to any one of Aspects 1-40, wherein the alkylcarboxylic acid manganese is manganese stearate.

[0165] Aspect 39. The method according to any one of Aspects 1-40, wherein the alkyl carboxylate is selected from the group consisting of C12-C24-alkyl carboxylates and combinations thereof.

[0166] Aspect 40. The method according to any one of Aspects 1-40, wherein the mixture of waxes comprises waxes with an average carbon chain length of about C42 to C47, wherein the mixture of fatty acids comprises fatty acids with an average carbon chain length of about C42 to C47, or both. Example

[0167] Having described aspects of this disclosure, the following examples illustrate some additional aspects of this disclosure. While aspects of this disclosure have been described in conjunction with the following examples and corresponding text and drawings, it is not intended to limit the aspects of this disclosure to these descriptions. Rather, it is intended to cover all alternatives, modifications, and equivalents included within the spirit and scope of this disclosure. Efforts have been made to ensure accuracy regarding figures (e.g., quantities, temperatures, etc.), but some errors and deviations should be accounted for. Unless otherwise indicated, parts are by weight, temperatures are in °C or ambient temperature, and pressures are at or near atmospheric pressure.

[0168] Example 1 - High-conversion chemical upgrading cycle of polyethylene, polypropylene and their mixtures to high-value surfactants ring Summary On the one hand, plastic waste causes serious health and environmental problems. On the other hand, fatty acids are biologically beneficial; they are produced by algae, plants, and animals, serving as building blocks of cells and important dietary fuel sources (e.g., butter). Therefore, converting plastic waste into fatty acids is a very attractive approach to addressing plastic waste pollution, transforming it into high-value, high-volume chemicals. This paper reports a method for converting polyethylene (PE) and polypropylene (PP) into fatty acids with an average chain length of ~C42-C47 at a conversion rate of nearly 90%. This process can be applied to linear PE and PP, as well as cross-linked PE and PP and their mixtures, without requiring complex catalysts, stringent reaction conditions, or separation processes. Temperature gradient thermal decomposition is key to controlling the distribution of products after degradation. Following a tandem oxidation-hydrolysis reaction, waxes are further recycled to fatty acids after oxidation and saponification on manganese stearate in air. Thermodynamically and kinetically, PP is more favorable than PE. β - Scission produces more olefin wax and fatty acids with higher acid values. The applicant further converts the fatty acids into high-value surfactants with a large market capacity, opening up pathways to upgrade recycled polyolefin waste for use in markets including lubrication, cosmetics, cleaning, emulsification, foaming, and water treatment.

[0169] introduction Chemical upgrading and recycling increases product value and is considered a solution for converting post-consumption waste into high-value chemicals, such as converting PS into arylcarboxylic acids and aryl ketones. 9-11 However, due to the high ceiling temperature, chemical upgrading cycles for PP and PE are difficult. 12 Furthermore, the lack of heteroatoms (or weak bonding, e.g., esters in PET) in the polymer chain cannot provide selective chain cleavage sites. Therefore, product control is extremely challenging. Recently, short-chain olefin-assisted cross-metathesis and iridium-based catalysts have been used to address this challenge. 13 and platinum-based catalysts 14 The hydrogenolysis-aromatization reaction produces fuel and improves the selectivity for the aryl moiety in the upgrading cycle of PE. PE can also be converted to propylene via dehydrogenation and tandem isoethylene alcoholysis. 15Considering the techno-economic benefits of increasing product value and the versatility of both PE and PP, converting polyolefins into high-value fatty acids or ionic surfactants is attractive, as PE and PP are inherently aliphatic. Furthermore, surfactant products have significant market demand (i.e., comparable to plastics) and high economic value (i.e., higher than fuels, waxes, and conventional aromatic compounds) (Table 1). Importantly, surfactant products such as soaps are made from fatty acids of varying chain lengths and are often blended with ketones and aldehydes to soften the product and modulate fragrance release. 16 This reduces the need to remove ketone and aldehyde byproducts during the upgrading cycle of PE and PP. Biodegradation uses microorganisms to convert PE into fatty acids, but the fermentation period is too long (>10 days) to be practically deployed in the chemical industry. 17 Chemically, Novoloop ® The method and hydrothermal reaction using strong oxidants rapidly degrade PE, but produce uncontrollable short-chain fatty acids and require harsh reaction conditions such as strong nitric acid and high pressure. 18 Recently, metallization of PE with Zr and alkylaluminum has yielded better-controlled products with conversion rates up to 40%, and the catalyst can be operated under conditions free of O2, CO2 and H2O. 19 Therefore, there is a great need for time- and material-efficient methods that utilize non-corrosive chemicals, atmospheric pressure, and air-resistant reaction conditions to effectively convert both PE and PP into fatty acids with large market capacity, preferably without additional sorting / separation, but with high selectivity and conversion rate.

[0170] The applicant reports a gradient temperature pyrolysis method that selectively decomposes both PE and PP into chains with an average carbon number of ~42-47 at atmospheric pressure (Figures 1A and 1B). The temperature gradient in the reactor rapidly quenches the vaporized wax and prevents further degradation into smaller molecules (Figure 1C). The intermediate products are then oxidized to ketones and fatty acids with high conversion rates and high acid values ​​(Tables 2 and 1B). Figure 1D The company transforms health- and environment-related polyolefin waste into bio and environmentally beneficial chemicals. Through subsequent saponification, the applicant obtains soap-based products containing fatty acid salts as ionic surfactants and ketones as soap softeners. Simply blending the soap base with additives (e.g., fragrances) can produce commercial soap bars and liquid detergents (see exemplary products in Figure 1A) with a market value exceeding that of typical chemical products such as fuels and alkyl aromatic compounds. 10 Results and Discussion PE (~500 mg) was loaded into a custom-designed quartz reactor (Figs. 1A and 6) and purged with a controlled composition of gas (N2, 10 vol% O2 in N2, or air). Degradation was initiated by heating the bottom of the reactor to ~360°C in three steps at 5 min ~100°C increments. Polymer “smoke” (Fig. 5) indicated the vaporization of fragmented polyolefins or waxes. The waxes were condensed and solidified in the cold section of the reactor to prevent further fragmentation into shorter hydrocarbons. Wax yields from PE degradation in N2 (PE-N2-wax), 10 vol% O2 (PE-O-wax), or air (PE-air-wax) were 89 wt.%, 79 wt.%, and 56 wt.%, respectively (Fig. 2A and Table 2, Experiments 1–3, 7–9, and 13). In the control experiment without a temperature gradient in N2, the intermediate waxes were all short-chain hydrocarbons with 8 carbons or less (Fig. 1C).

[0171] Gas chromatography-mass spectrometry (GC-MS, Figure 2B) was used to characterize the wax composition, showing that it was mainly solid wax with small amounts of light hydrocarbon products (~10 wt.% C8 and below). Figure 6 Each main peak can be split into bimodal peaks of alkenes and alkanes with the same number of carbon atoms. Figure 7 (and Figure 12), similar to degradation in a flow reactor. 20 In the presence of O2, PE-O-wax and PE-air-wax exhibit GC-MS peaks and molecular ion signals similar to PE-N2-wax. PE-O-wax and PE-air-wax show stronger intensity than PE-N2-wax at shorter elution times (Figure 2B), indicating shorter hydrocarbon lengths and lower average molecular weights due to accelerated degradation of the radical group. 21 The yield of PE-air-wax was too low (~56%), although it was higher than the yield reported in the literature. 14，22，23 However, it is practically unsuitable for generating hydrocarbons suitable for downstream surfactant production (Figure 2A); therefore, no further characterization of PE-air-wax was performed. High-temperature gel permeation chromatography (HT-GPC) confirmed the decrease in the molecular weight of the wax (Figure 9B). Since HT-GPC cannot resolve the precise molecular weight within this range, and GC cannot detect low-volatility long hydrocarbon chains (>C40), 24 Therefore, atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was used to analyze the less volatile fractions. The spectra of PE-N2-wax and PE-O-wax show heavier waxes with average m / z centered around 640 and 590, respectively (Figure 9 and Table 3). The number average of PE-N2-wax (… M n) molecular weight and weight-average weight M The molecular weight of w) is estimated to be M n ~ 640 Da andM w ~ 700 Da, corresponding to an average carbon number of ~ 45. In comparison, PE-O-wax has an average carbon number of ~ 42 ( M n ~ 590 Da and M w ~ 650 Da). Experiments using heteronuclear multi-bond correlation (HMBC) and heteronuclear single quantum correlation (HSQC) (Figure 2C, Figure 12 and 12) were conducted. Figure 13 The structures of PE-N2-wax and PE-O-wax were further characterized by nuclear magnetic resonance spectroscopy (NMR). NMR confirmed the presence of unsaturated carbon in both PE-N2-wax and PE-O-wax, revealing a predominant 2-propenyl group (H2O) at the chain ends. 1 NMR δ 5.0 and 5.8, C 13 NMR δ 114 and 138) and minor internal olefins (C 13 NMR δ 123-131). The presence of O2 slightly oxidizes PE-O-wax and produces ketones, aldehydes and esters (Figure 11).

[0172] The wax was further cyclically grown in air at 150°C on Mn compounds for 10 h. Despite the significant success shown by inorganic MnO2 and KMnO4 in the oxidation of paraffins, 25，26 However, they were ineffective in oxidizing PE-derived waxes, likely due to their low miscibility, showing no significant carbonyl signal after 24 h (Figure 12). In contrast, manganese stearate catalyzed the oxidation of PE-derived waxes much faster, thanks to the better dispersion of the catalyst in the organic medium. 27 The oxidation rate on manganese stearate under constant gas flow, as shown by the carbonyl index (CI), was independent of whether the substrate was PE-N2-wax or PE-O-wax. PE-O-wax showed a higher final CI due to its higher initial value compared to PE-N2-wax. With the support of HMBC, the oxidation of PE-O-wax on manganese stearate enhanced the carbonyl concentration within the first 6 h (Figure 12 and...). Figure 13 C 13 NMR (δ 160-206), primarily producing aldehydes and minor amounts of esters, ketones, and carboxylic acids. The dominance of aldehyde intermediates is highly consistent with the simulation results described below. Because aldehydes are readily oxidized further, they are converted to acids in the subsequent 2-hour oxidation and subsequent saponification (…). Figure 2D C 13 NMR δ 180). The saponification solution was neutralized with HCl to give fatty acids (PE-O-FA). After washing and drying under vacuum, PE-O-FA was characterized by HMBC, showing a predominantly carboxylic acid and a small amount of ketone. Aldehydes were no longer detected. Figure 14 The carboxyl group in fatty acids is associated with two types of protons. Figure 2D H 1NMR (δ 2.0 and 1.5) indicates a possible carboxyethyl end group. The acid value (AN) of PE-O-FA was determined by titration, yielding a typical AN of 96 mg KOH / g. Figure 1D (and Table 4), which slightly exceeds the theoretical value of ~80 mg KOH / g for 700 g / mol monocarboxylic acid (C47).

[0173] After successfully converting PE to fatty acids, the process was applied to PP under similar reaction conditions (N2, 10 vol% O2 in N2, and air). Degradation products in N2 (PP-N2-wax), 10 vol% O2 (PP-O-wax), and air (PP-air-wax) showed wax yields of 92 wt.%, 85 wt.%, and 87 wt.%, respectively (Figure 3A and Table 2, Experiments 4-6, 10-12, and 14), along with small amounts of coke and gaseous products. Figure 15 Unlike PE, PP wax yields remain high in air, eliminating the need for controlled gases in the process and making it more economically attractive. Therefore, no further investigation was conducted on the degradation of PP in 10 vol% O2. GC-MS analysis of PP-derived waxes showed a broad multimodal distribution of the major olefin products in GC-MS. Figure 16 The carbon numbers of most alkenes are multiples of 3 (or 3n in the C9-C36 range), while the remaining alkanes, alkenes, and dienes are primarily 3n+1. This interesting phenomenon suggests that the main degradation mechanism is likely chain breakage along the PP backbone, as each PP repeating unit has three carbons (consistent with the simulations below). In the presence of air, the chromatogram of PP-air-wax becomes crowded and difficult to analyze (Figure 9A). Similar to previous reports, 28 PP-N2-wax and PP-air-wax were characterized by HT-GPC and APCI-MS (Figure 9B and 9C). Figure 9C The latter shows slightly more short hydrocarbons due to air-induced oxidation. Similar to PE degradation, PP-N2-wax and PP-air-wax primarily contain terminal olefins and small amounts of internal olefins (Figure 3C). Figure 19 and Figure 20 The dominant form of the terminal olefin is 2-methyl-2-propenyl, as evidenced by the correlation in HMBC and HSQC. Additionally, some minor forms of the terminal olefin are noted, with C... 13 The main forms overlap in NMR, but... 1 They exhibit slightly different chemical shifts in the 1H NMR spectrum. Figure 17A Due to its low abundance, the chemical structure could not be determined. PP-air-wax contains ketones, aldehydes, and esters due to oxygen-induced oxidation (Fig. 18), but the alkenyl region is similar to that of PP-N2-wax.

[0174] Similar to PE-derived waxes, the upgrading cycles of PP-N2-wax and PP-air-wax were carried out in air at 150°C on manganese stearate. PP-N2-wax oxidized more slowly than PP-air-wax, which showed a CI of ~0.9 after 4 hours of oxidation (Figure 12C). According to NMR-HMBC, oxidation introduced acid, aldehyde, and ketone carbonyl groups (…). Figure 19 The fatty acid obtained after hydrolysis (PP-air-FA) was characterized by NMR-HMBC, showing no detectable aldehydes but a stronger ketone carbonyl signal than PE-O-FA. The acidic carbonyl group exhibited three correlations with the proton (…). Figure 3D and Figure 22 The presence of 169 mg KOH / g indicates a possible 2-carboxypropyl terminal structure. PP-air-FA exhibits an AN of 84 mg KOH / g, significantly higher than the theoretical value of 84 mg KOH / g for a monocarboxylic acid of 670 g / mol (C46) (Table 4), suggesting the presence of a polyacid.

[0175] After successfully converting both PE and PP to wax and fatty acids with high conversion rates, the applicant tested the degradation of a mixture of HDPE (25 wt.%), PP (25 wt.%), LDPE (25 wt.%), and cross-linked PE (XLPE, 25 wt.%), producing wax in 80% yield in N2. The wax was further recycled to fatty acids, yielding an average acid value of 57.3 mg KOH / g. Figure 1D (See Table 4). Long-chain ketones and aldehydes may be present in the product. Ketones and aldehydes can advantageously adjust the viscosity of the product and be used as soap softeners. 29 It also regulates the release of fragrances. 16 Since ketones and aldehydes are important additives in soaps and cosmetics, there is no need to separate and reduce the carbonyl groups of ketones and aldehydes.

[0176] The applicant used the Benson group additivity method. 30，31 To evaluate PEβ-fracture and PP β-fracture Standard Gibbs free energy (∆ G 0 (Equation 6 and Table 6). Thermodynamically, olefin formation by PP and PE at 298 K is unfavorable (Table 7). At increasing temperatures (633 K and 823 K), β-cleavage of PE and PP becomes increasingly thermodynamically favorable. Under experimental conditions (633 K), both the enthalpy of reaction and Gibbs free energy of PE and PP degradation decrease (Δ). H PP,633K =88.9 kJ / mol and Δ GPP,633K =-5.60 kJ / mol; Δ H PE,633K =94.3 kJ / mol and Δ G PE,633K =1.20 kJ / mol). However, this remains slightly unfavorable for PE. Both PE and PP exhibit favorable β-fracture (Δ mol) after the temperature rises to 823 K. H PP,823K =86.9 kJ / mol and Δ G PP,823K =-33.1 kJ / mol; Δ H PE,823K =92.9 kJ / mol and Δ G PE,823K =-26.5 kJ / mol). The kinetic parameters and constants of β-fracture were also predicted using the group addition method based on the model reaction (Figure 5A). 32 At all temperatures, PP β-fracture exhibits a lower activation energy and a higher kinetic constant than PE (Table 8). Generally, olefin formation from PP β-fracture is more favorable and faster than from PE (which is very consistent with the experimental and simulation results above). Observations of the temperature dependence of PE and PP β-fracture are also very consistent with the literature, where the olefin yield from PE pyrolysis increases from ~30% at 500 K–700 K to ~70% above 800 K, while the olefin yield from PP pyrolysis remains high (>70%), independent of temperature. Figure 22 ). 20, 33-40 Summary and Conclusion This work reports a general strategy for chemically upgrading PE and PP to fatty acid and surfactant products, such as soaps and detergents. The process begins with temperature gradient pyrolysis to form aliphatic chains of controlled length, followed by oxidation to produce fatty acids. Fatty acids have wide applications, and the market value of their downstream surfactant products is at least twice that of the virgin plastics, representing an economically competitive process for plastic waste utilization. Furthermore, the market capacity of surfactants matches the market capacity of end-of-life plastic waste, thus representing a capacity-influenced approach to plastic waste removal. Controlled pyrolysis in a temperature gradient reactor is key to controlling the wax product yield, ensuring a wax yield close to 90% rather than small gaseous molecules. Unlike other existing processes, 19This process is oxygen-tolerant and does not require expensive catalysts or stringent reaction conditions. More importantly, it is applicable to mixtures of PE and PP without separating these two commercially available plastics, which are lighter than water. The resulting fatty acids (96 mg KOH / g for PE-derived fatty acids and 169 mg KOH / g for PP-derived fatty acids) exhibit good acid values. The applicant anticipates that this process can be applied to a variety of other plastic wastes. 41-43 Given its potential to generate high-value, high-market-volume detergents and disinfectants, this process should be attractive to industries that are recycling / upgrading the large amounts of polyolefin waste generated during the COVID-19 pandemic.

[0177] Experimental Section Material Unless otherwise stated, all chemicals were purchased from Sigma-Aldrich and were >99% pure. Deuterated benzene (C6D6, 99.8%), toluene (C7H8, 99.8%), and p-xylene (C8H...) were among the chemicals used. 10 (99.5%) was purchased from Cambridge Isotope Laboratories, Inc. and used as is. Manganese stearate and Mn / Ni oxide were synthesized according to the procedure described in the literature. 44，45 Degradation by Tuoda Quartz tcl ® It is carried out in a custom-designed quartz reactor.

[0178] instrument Gas chromatography (GC) analyses were performed on a 6890 GC equipped with a DB-5 capillary column (30 m long × 250 µm ID, 0.25 µm film thickness) from J&W Scientific (Wilmington, DE) and a flame ionization detector (FID). The following operating parameters were used for each GC analysis:

[0179] All gas chromatography-mass spectrometry (GC-MS) analyses were performed on an Agilent 6890 GC with a 5973 mass-selective detector (MSD). MS Wiley libraries were used for peak identification. Separations were performed using the same GC column under the same operating conditions. The MSD transfer line temperature was 280 °C.

[0180] Quantitative proton nuclear magnetic resonance (Q-) 1¹H NMR spectroscopy was performed on a Bruker Avance II 600 spectrometer in deuterated solvent at 600 MHz, with a relaxation time of 5 s and 128 scans. Due to the poor solubility of PE-N₂-wax in deuterated benzene, PE-N₂-wax was characterized in deuterated p-xylene. Unless otherwise specified, all other PE and PP-derived waxes, oxidized waxes, and soaps were dissolved in deuterated benzene.

[0181] Heteronuclear multi-bond correlation (HMBC) and heteronuclear single quantum correlation (HSQC) experiments were performed on a Bruker Avance II 600 spectrometer in a deuterated solvent at 600 MHz, with a relaxation time of 2 s, 16 scans, and a digitization increment of 400.

[0182] Fourier transform infrared spectroscopy (FTIR) was performed at room temperature using a PerkinElmer ATR-FTIR (model Spectrum 100) at 4000 cm⁻¹. -1 -1000 cm -1 Within a range of 4 cm -1 The resolution was 256 scans.

[0183] Using a thermal imaging camera (HIKMICRO) TM E1L ® The reaction temperature was determined at a resolution of 160×120. Figure 6 ).

[0184] Melt rheology studies were performed on an AR-G2 rheometer (TA Instruments). All measurements were performed in oscillating time-scan mode using 25 mm ETC aluminum parallel plates at 100 °C and a 1 mm gap spacing (frequency: 1 Hz).

[0185] Atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was performed on a Shimadzu LCMS9030, which was interfaced with a UPLC (LC-40B X3) equipped with an autosampler (SIL-40C X3) and a column oven (CTO-40C) (both from Shimadzu). The flow rate was maintained at 200 μL / min at an oven temperature of 40 °C. The mobile phase consisted of solvent A (60:40 water:acetonitrile, containing 10 mM ammonium formate) and solvent B (90:10 isopropanol:acetonitrile, containing 10 mM ammonium formate), maintained at a ratio of 5:95 (A:B). Samples were prepared in xylene, and aliquots (90 μL) were mixed with isopropanol (10 μL) containing 0.1% formic acid. These solutions were analyzed in positive ion mode at a flow injection rate of 2 μL / injection. Data was recorded in profile mode using a mass range of 100 m / z–1500 m / z and a scan time of 0.1 sec. Ionization was performed using a dual ionization source (DUSI), with the corona needle voltage set to 4.5 kV and the interface set to 4 kV. Atomizing gas flow rate: 2.0 L / min; heating gas flow rate: 10.0 L / min; interface temperature: 300 °C; desolvation temperature: 526 °C; drying gas flow rate: 10.0 L / min; DL temperature: 250 °C; heating block temperature: 400 °C.

[0186] PE and PP degradation Degradation in the N2 / O2 mixture is described below, and degradation in N2 and air follows a similar procedure. PE or PP (~500 mg) was added to a custom-designed quartz reactor (Figure 5). The reactor was capped with a quartz plate and sealed with fluorinated rubber O-rings. The reactor assembly was reinforced by two clamps. The gas inlet was sealed with a fluorinated diaphragm and secured with a Teflon cap, while the gas outlet was initially kept open (Figure 5, Step 1). The reactor was then degassed with a mixture of N2 and air for 15 min. Simultaneously, heated and cooled water were supplied to balance the internal pressure with the ambient pressure (Note: heating the reactor and supplying cooling water after degassed will over-pressurize and de-pressurize the reactor, respectively). The reactor was gradually heated (~100°C / 5 min), and the internal temperature reached ~360°C after ~15 min (Figure 5, Step 2). The N2 and air flow was maintained for an additional 30 s and stopped immediately after the polymer in the reactor began to “smoke” (Figure 5, Step 3). “Smoke” indicates the start of polymer degradation. A red laser beam can detect light smoke early in the degradation process (Figure 5). Immediately after stopping the gas flow, the outlet is sealed with a fluorinated diaphragm and secured with a Teflon cap. The quartz plate at the top of the reactor is cooled by a stream of cold air to maintain its low temperature (Figure 5, step 4). At this point, only the bottom of the reactor is hot, and the reactor walls and ceiling are close to room temperature. The reaction is stopped after 16 hours, and the reactor is cooled to room temperature.

[0187] PE and PP upgrade cycle The upgrade cycle consists of two steps. 1. Oxidation. In a typical experiment, 500 mg of wax and 25.0 mg of manganese stearate (5 wt.% relative to the wax mass) are transferred to a reactor equipped with a stirrer. A constant airflow is supplied to the reactor at a rate of ~50 mL / s. The internal temperature is adjusted to 150 °C, and the reaction is carried out for 10 h. 2. Saponification. After oxidation, the oxidation product is saponified in 0.1 M KOH (wax concentration, ~20 mL / g). The aqueous mixture is refluxed for 12 h and then transferred to a clean beaker. Note that prolonged saponification time in concentrated alkali may etch the glass. Reactor, forming silicates The pH was adjusted to ~1 using concentrated HCl, and the fatty acids were crushed and floated to the surface of the solution. The fatty acids were collected by centrifugation and washed with water until the pH level reached ~7. Etching of glassware caused by KOH may be due to... Silicates appeared at the bottom of the centrifuge tube. The fatty acids were dried and weighed to assess the yield.

[0188] Support information Experimental methods.

[0189] Characterization of PE and PP degradation 1. Gas Flow and Reactor Internal Temperature. The degradation atmosphere was controlled by a controlled flow rate of gas. The internal temperature of the quartz reactor was measured using an IR camera (Figure 5A). During the degradation reaction, the temperature at the bottom of the reactor was set to ~360°C.

[0190] 2. Yield Determination. The wax yield was measured directly using an analytical balance. First, the wax condensed on the quartz cap was scraped into the reactor using a piece of soft plastic, and the residue was washed into the reactor with hexane. Then, approximately 100 mL of hexane was added to the reactor, and the reactor was capped for reflux. The wax on the reactor walls was also collected by refluxing the hexane. Note that cooling water for the reactor should not be used during reflux. After reflux, the hot wax / hexane solution was transferred to a pre-weighed flask (m0), and the solvent was removed using a rotary evaporator (50°C, 100 mbar). Any residual hexane and light hydrocarbons were allowed to vaporize overnight. The final mass (m1) was recorded to assess the mass of the intermediate wax (m1-m0).

[0191] 3. GC and APCI Characterization. After PE or PP degradation, the reactor was cooled to room temperature. The negative pressure in the reactor was brought into equilibrium with the environment by refilling with N2 through the gas inlet. The gas in the reactor was immediately sampled and characterized using GC-MS and GC-FID. Liquid and solid products were collected using a scraper, transferred to GC vials filled with toluene, heated on a hot plate until completely dissolved, and then sampled for GC analysis. Note: For PE-derived waxes, the solution during GC-MS injection... The room must be kept warm because PE-derived waxes have low solubility in toluene at room temperature. Xylene is a better solvent, but it... They typically contain complex isomers that may overlap with wax peaks in GC. For APCI-MS characterization, the wax was dissolved in xylene because hydrocarbons have better solubility in xylene at elevated temperatures. The solution concentration was approximately 0.5 mg / mL. The solvation of PE-N2-wax in xylene is slow, and therefore it was heated to 110 °C until completely dissolved.

[0192] The number-average molecular weight of the wax was determined based on GC (equation S1) and APCI (equation S2). M n ) and weight-average molecular weight ( M w

[0193] in m i and n i It refers to the mass and number of moles of the compound; MW i The molecular weight of the compound is determined by GC-MS or APCI-MS (Figure 9); K represents the FID mass response factor, which, according to the literature, can be assumed to be a constant for alkanes and alkenes; 1, 2A i It is the peak area of ​​GC-FID.0.

[0194]

[0195] in I i It represents the ionic strength of the ionized substance; C represents the MS molar response factor, and since the value of long-chain hydrocarbons with different carbon numbers varies very little, it is assumed to be a constant (0.8-1.1). 3 Characterization of PE and PP upgrade cycles 1. Oxidation kinetics study. Using the carbonyl index ( CI The wax oxidation was monitored, and the index was assessed using ATR-FTIR. After degradation, the wax products were separated and fractionated into 4–5 flasks, each containing approximately ~100 mg of wax and manganese stearate catalyst (5 wt.%). Parallel oxidation was performed for different times at the same temperature and gas flow. The carbonyl index was calculated using equation S3.

[0196]

[0197] in h C=0 Yes, it's about 1700 cm. -1 The intensity of the carbonyl stretching peak at the position; h C-H It is 2800 cm -1 The intensity of the CH tensile peak at that location.

[0198] 2. Acid Value Determination. The acid values ​​of fatty acids derived from PE and PP were determined using a modified titration method based on standard GB / T 5510-2011. Toluene was used as the solvent, instead of benzene introduced in GB / T 5510-2011, as suggested by similar standard ISO 7537:1997, due to toluene's lower toxicity and better solvation ability. Theoretical values ​​were estimated using equation S4, assuming one acid group per molecule.

[0199]

[0200] Where AN is the theoretical acid value; M KOH It is the molecular weight of potassium hydroxide; and M FA It is the number-average molecular weight of fatty acids.

[0201] Thermodynamic and kinetic parameters of PE and PP degradation The degradation of PE and PP follows an initiation, radical transfer / depolymerization, and termination mechanism. During the radical transfer step, β-fracture is the main contributor to chain breakage and olefin formation. Therefore, the thermodynamic and kinetic parameters of β-fracture are evaluated to understand the differences in PE and PP degradation.

[0202] 1. Thermodynamic parameter prediction using the Benson group addition method. The β-fracture thermodynamics of PE and PP at different temperatures were evaluated using data from gaseous alkanes and alkenes at 298 K calculated using the Benson group increment theory. 4, 5 The incremental values ​​for parts g1 to parts g9 are defined and compiled in Table 6.

[0203] The incremental values ​​of the parts (Table 6, g1 to g9) at 633 K and 823 K were estimated using Kirchhoff's laws. The heat capacity term was obtained by fitting the heat capacity values ​​at various temperatures using an empirical expression for heat capacity (Equation S5).

[0204]

[0205] in C P The heat capacity is at constant pressure; a, b, and c are constants; T is temperature. The enthalpy and entropy of the linear PE group (Equation S6) are:

[0206] Where n and m are the number of repeating units.

[0207] The enthalpy and entropy of the PP group are

[0208] The enthalpy and entropy of the olefins obtained by β-cleavage of the PE group are...

[0209] The enthalpy and entropy of the olefins obtained by β-cleavage of the PP group are...

[0210] The enthalpy and entropy of the oligomer groups obtained by β-cleavage of the PE group are...

[0211] The enthalpy and entropy of the oligomer groups obtained by β-cleavage of the PP group are...

[0212] The predicted thermodynamic parameters are summarized in Table 7.

[0213] 2. Kinetic parameter prediction using the group addition method. Based on the corresponding model reaction, the group addition method is used. 6 β-fracture kinetics were calculated for PE-based and PP-based groups. Labeled carbons (C1, C2, C3) correspond to the labeled carbons in the reference reaction, where a methyl group adds to a propyl group to form ethylene. This model reliably assesses the contribution of the nearest atom / group to the kinetic parameters. The pre-exponential factor (A) and activation energy at 298 K were calculated. E a And listed in Table 8. Because the effect of temperature on the contribution of functional groups is small, its effect on kinetic parameters is neglected. The change in the sum of functional groups of activation energy (ΔGAV) over a wide temperature range of 300 K–1300 K is shown. Ea The change in the sum of the groups of the pre-exponential factor (ΔGAV) is less than ±4 kJ / mol relative to 125 kJ / mol. lgA The value is less than ±0.6 lg( / s) relative to 13.181 lg( / s). 6 To simplify the calculation of the pre-exponential factor, the number of events (n) is omitted. e ).

[0214] Quantitative NMR analysis of alkenyl group concentration 1. Calibration of deuterated solvents. Deuterated benzene (C6D6) and p-xylene (C8D6) were measured using an external reference method. 10 The common benzene (C6H6) and p-xylene (C8H6) in the group 10 The concentration of the deuterated solvent (C6D6 or C8D) was accurately measured using an analytical balance. 10 The mass of C6H6 (~1 mL) and external reference CHCl3 was used. After adding CHCl3 to the deuterated solvent, the mixture was sealed and vortexed to ensure thorough mixing. The mixture was then immediately characterized by NMR. The C6H6 and C8H6 in the deuterated solvent... 10 The concentrations were calculated to be 3.273 mg / g and 1.656 mg / g, respectively.

[0215] 2. Determination of alkenyl group concentration in waxes and fatty acids. The concentration of alkenyl groups in the products after degradation and upgrading cycles was determined using an external reference method. Common benzene (C6H6) and p-xylene (C8H6) in deuterated solvents were used. 10 Used as an external reference. Accurately measure the mass of degradation and upgrading cycle products, as well as the deuterated solvent, in a clean GC vial. Seal the vial with a PTFE cap and warm to 60°C for complete dissolution. Immediately characterize the mixture by NMR to avoid any potential vaporization. Determine the mass concentration (mol / g) of the alkenyl groups using equation S12.

[0216]

[0217] Where C C=C It is the mass concentration of the alkenyl group; m d-溶剂 It refers to the quality of the deuterated solvent; M d-溶剂 It is the molar mass of the deuterated solvent; C CH It is a common deuterated solvent, such as benzene (C6H6) and p-xylene (C8H6). 10 The concentration of ); n phen-H Is it C6H6 or C8H? 10 The number of H's; r It is an alkenyl group relative to C6H6 or C8H 10 The ratio; n ene-H It refers to the number of H atoms on the alkenyl group; PE and PP have 3 and 2, respectively. m It refers to the quality of the sample.

[0218] Supplementary discussion.

[0219] Oxidation of alkenes and potential side reactions. During oxidation on manganese(III) stearate, the concentration of alkenyl groups in PE and PP-derived waxes decreased sharply. After 6 h of oxidation, the alkenyl concentration in PE-O-wax decreased from ~1 mmol / g to ~0.8 mmol / g, and after 10 h, it decreased to almost zero. Figure 21 PP-air-wax experienced a similar decrease from ~2 mmol / g to ~0.9 mmol / g after 2 h, but the alkenyl concentration recovered to ~1 mmol / g after 4 h due to the formation of internal olefins. This initial decrease in alkenyl concentration can be attributed to two types of reactions: 1) polymerization and oxidative crosslinking of the olefin wax; 2) alkenyl-related oxidation to carbonyl groups. Due to thermal initiation, 7 peroxide, 8 Or react with other alkenes, 7, 9 Some monomers may polymerize in air, leading to an increase in molecular weight and viscosity. Although rheometer analysis confirmed the viscosity increment during heat treatment (~20 Pa S), according to APCI-MS, PE-O-FA ( M n ~700 Da and M w ~750 Da) and PP-air-FA ( M n ~670 Dahe M wThe molecular weight increment (~740 Da) is relatively small (< 100 Da) (Figure 9 and Table 2). Considering the high alkenyl conversion (>50%) and the introduction of oxygen atoms into the hydrocarbon via carbonyl and acid groups, polymerization must be secondary. Therefore, the primary function of the alkenyl group is to form acids and other oxygen-containing groups. It is said that an alkenyl group can be oxidized to a carboxylic acid, and the theoretical acid values ​​of PE-O-wax and PP-air-wax are less than the determined AN (based on variations in alkenyl concentration (~1 mmol / g)). Figure 1D Therefore, not all acids are transformed through alkenyl oxidation, and alkyl group oxidation is another important contributing factor to carboxylic acids.

[0220] Table 1. Prices of different products related to the project.

[0221]

[0222] a Crude oil prices were obtained from Brant (November 2021). b Paraffin prices are from ECHEMI, converted from RMB to USD (November 2022). c BTX consists of benzene, toluene, and xylene. BTX prices are obtained from Statista, ECHEMI, and Statistics. (2021) d Stearic acid prices are from ECHEMI, converted from RMB to USD (November 2022). e The price of polyolefins is obtained from Statista (2022). f Based on the US market, the average price range for a single soap unit (0.5 kg - 1 kg) is derived from common soap products such as shower gel, bar soap, liquid soap, and disinfectant.

[0223] g The average price from 10 different suppliers on IndiaMart, from Converted to $ (December 2022).

[0224] Table 2. Yields of polymer degradation at different oxygen levels

[0225] a The oxygen volume ratio is controlled by N2 gas and air flow rate.

[0226] bThe wax yield is calculated based on the weight of the wax measured using an analytical balance.

[0227] Table 3. Average molecular weight of PE and PP derived waxes and fatty acids.

[0228]

[0229] a Molecular weight was assessed by GC and APCI-MS using equations S1 and S2.

[0230] b Due to poor separation in GC, the molecular weight cannot be estimated.

[0231] c Due to ion fragmentation, the value is rounded to two significant digits.

[0232] Table 4. Fatty acid yield and acid value (AN).

[0233]

[0234] a Oxidation at 150°C with an airflow rate of ~1 mL / s yields fatty acids with low acid values.

[0235] b Oxidation at 150°C with an air flow rate of ~50 mL / s yields fatty acids with high acid values.

[0236] Table 5. C=C concentrations in waxes, oxidized waxes, and fatty acids.

[0237]

[0238] a The samples were obtained from the experiments in Table 2.

[0239] b '-1' and '-2' are oxidized waxes and fatty acids obtained from wax oxidation.

[0240] c 7-1 was taken after 6 hours of oxidation.

[0241] d 14-1 was sampled 2 h after oxidation.

[0242] e The mass concentration of the alkenyl group was determined using equation S12.

[0243] Table 6. Benson group increments for some subunits at 298 K, 633 K, and 823 K. Benson group increments for subunits present in PE, PP, and polymer groups at 298 K. All data are from the NIST database. 5

[0244] Calculated Benson group increments of subunits present in PE, PP, and polymer groups at 633 K and 823 K. 5 .

[0245]

[0246] a The group increment values ​​at 633 K and 823 K were calculated using Kirchhoff's laws. Equation S5 was used to estimate... C P,气体 .

[0247] Table 7. Thermodynamic parameters of β-fracture of PE and PP at different temperatures.

[0248]

[0249] Table 8. Group addition value (ΔGAV) and kinetic parameters of β-cleavage reaction at different temperatures

[0250] a For simplicity, the effect of temperature on kinetic parameters has been ignored.

[0251] b The exponential factor is an approximation because it ignores the number of events.

[0252] Example 2 - Adjusting hydrocarbon chain length through thermal decomposition of polyolefins and subsequent upgrading and recycling into functional molecules Summary Since the mid-1950s, global plastic production and consumption have exacerbated plastic waste pollution. Therefore, designing practical strategies for plastic waste management to mitigate the inherent ecological challenges has become urgent. In this paper, the applicant reports a method for controlling the molar mass and molar mass distribution of the thermal decomposition products of polyolefins using the temperature of a coolant fluid (e.g., water). Following this strategy, the thermal decomposition of polyethylene (PE) and polypropylene (PP) at ≤400°C is carefully tailored to produce oils with hydrocarbon lengths in the C7-25 range, without any catalysts or additives. Notably, the oils from PE, PP, and mixtures thereof are characterized by a concentration of synthetically useful α-alkenyl groups that is at least twice as high as in waxes. In a subsequent step, sulfuric acid is added to the alkenyl groups in the oil, followed by neutralization with potassium hydroxide, providing a sulfate detergent with excellent foaming behavior even at room temperature. Ultimately, the rapid, catalyst-free, and hydrogen-free thermal decomposition and upgrading cycle of polyolefins provides a scalable and profitable technology for producing value-added chemicals (e.g., detergents) and contributes to addressing the plastic waste problem.

[0253] introduction Multiple strategies were explored, including zeolite-assisted pyrolysis, [7] Photochemical hydrocracking,

[11] and cross-alkane metathesis

[12] For example, Kassargy et al. studied USY zeolite used for PE pyrolysis at 450 °C and found that USY zeolite, characterized by acidic sites, significantly increased the oil fraction from 0 wt.% to 71 wt.%. [7] Cross-alkane metathesis (CAM) is a powerful polyolefin destruction strategy involving dehydrogenation, olefin metathesis, and rehydrogenation. [13-14] Jia et al. utilized the CAM strategy and evaluated the effect of iridium catalyst ligands on HDP from PE degradation.

[15] Due to enhanced selectivity for internal olefin intermediates, iridium catalysts characterized by bis(phosphonite) ligands provided high oil yields after 72 h of reaction. Ru / TiO2-catalyzed photochemical hydrocracking of PE at different hydrogen pressures yielded varying proportions of wax and liquid oil. Notably, HPD converted to a lower carbon number at a high hydrogen pressure of 40 bar, resulting in a high oil-to-wax ratio due to extensive polymer hydrolysis.

[11] Sadow and colleagues designed a heterogeneous catalyst for progressive PE hydrocracking, characterized by Pt nanoparticles supported on a mesoporous SiO2 (mSiO2) substrate.

[16] Compared to solid Pt / SiO2-mediated hydrocracking, the mesopores in mSiO2 produce narrower HPD and lower carbon number products. Typically, the above methods rely on expensive composite catalysts, high hydrogen pressures, and sometimes long reaction times to achieve high oil yields. Therefore, there is a strong need for feasible catalyst-free / hydrogen-free methods to regulate the oil-wax ratio in polyolefin thermal decomposition.

[0254] Long-chain bisulfate detergents are widely used in industrial and household applications as cleaning products and emulsifiers due to their excellent amphiphilic properties. Typically, sulfate detergents are made from fats, oils, and petrochemical-derived products.

[17] Therefore, the use of these raw materials could jeopardize global food resources and lead to the depletion of fossil fuels. [18-21] Therefore, it is crucial to develop alternative pathways for the sustainable production of synthetic detergents.

[0255] Recently, the applicant reported a simple method that uses temperature gradient thermal decomposition to convert PE and PP into intermediate waxes, followed by catalytic oxidation to produce fatty acids.

[22] To further improve product selectivity, the applicant aims to regulate the molar mass and distribution of PE and PP pyrolysis products. Using water as a coolant to control the temperature gradient, the applicant achieved tunable selectivity through a controlled ratio of solid wax to liquid oil. Furthermore, the applicant upgraded the relatively low-market-value pyrolysis oil rich in intermediate olefins into sulfate detergents through sulfuric acid treatment followed by neutralization. (Insert) The use of cooling fluids to regulate the temperature gradient and control the distribution of pyrolysis products demonstrates the versatility, effectiveness, and practicality of temperature gradient pyrolysis in obtaining detergent-related precursors from low-cost plastic waste resources.

[0256] Results and Discussion To enable PE and PP to degrade and upgrade into hydrocarbons with adjustable chain lengths, controlling the distribution of thermal decomposition products is crucial. In temperature gradient pyrolysis, the gradient is controlled by setting the bottom of the reactor at a high temperature (T1) and the top of the reactor at a low temperature (T2). T1 is high enough to induce polymer chain breakage, and T2 is low enough to quench the chain breakage reaction and condense the products. To control the product chain length (or molar mass, used interchangeably in this context) and chain length distribution, the applicant hypothesizes that T2 can be simply adjusted in the quenching / condensation zone. In the applicant's previous report,

[22] A constant cooling water circulation within the reactor plays a crucial role in ensuring that thermal decomposition does not primarily produce gaseous products. This observation led to the exploration of the temperature of the coolant (e.g., water) as a parameter for regulating the carbon number range of degradation products and increasing the fraction of thermally decomposed oil.

[0257] polyethylene To demonstrate this concept, firstly, by allowing room temperature water to flow through the reactor jacket, HDPE ( M w The PE (88.38 kDa) underwent thermal decomposition under T1 = 360 °C–400 °C and T2 = 28 °C (Fig. 23B, left). This degradation reaction yielded 91 wt.% wax in the condensation zone, composed of saturated and unsaturated hydrocarbons (Fig. 24A, left). Gas chromatography (GC) of the wax in hot hexane showed a single peak distribution centered at ~25.5 min, corresponding to C26 (Fig. 23D, black curve). In contrast, hot water flowing through the reactor jacket established T2–90 °C in the cold trap zone (Fig. 23B, right). The high T2 resulted in a distinct temperature gradient, which yielded 51 wt.% oil in the reactor headspace (Fig. 24A, PE product at 90 °C). Under the higher T2 reaction conditions, the oil composition shifted towards lower GC elution times, giving C14-centered hydrocarbons (Fig. 23D, red curve). Further characterization of the thermally decomposed oil by GC-MS revealed predominantly linear alkanes and alkenes, as well as minor amounts of dienes in the C7–C26 range. No cyclic or branched products were detected, indicating that intramolecular and intermolecular group recombination was negligible under the reaction conditions.

[23] Besides the oil, wax (27 wt.%) accumulated near the bottom of the reactor after 6 h of reaction. As confirmed by GC, the residual wax at T2=90 °C and the wax collected at T2=28 °C showed similar compositions, characterized by both olefin and alkane components. In addition to the oil and wax, the thermal decomposition of PE produced ~22 wt.% gaseous products, mainly propane, E Composed of 2-butene and pentane ( Figure 31 It is speculated that the 90°C cold trap allows for the liquefaction of vaporized hydrocarbons, which then flow back to the bottom of the reactor, creating a reflux-like phenomenon. Figure 32 (and video S1). Therefore, the observed changes in oil versus wax selectivity can be attributed to more sustained chain breaking and degradation resulting from longer residence times at T1 = 360°C–400°C. In contrast, the 28°C cold trap is not hot enough to cause the condensed products to melt in order to maintain hydrocarbon “reflux.” Therefore, the vaporized products are quenched and solidified on the walls of the cold trap. Two examples at controlled temperatures of ~28°C and 90°C demonstrate the ability to achieve tunable hydrocarbon chain lengths using the coolant temperature T2.

[0258] Further spectroscopic analysis of the HDPE-derived hydrocarbons revealed a large amount of α-olefins available for downstream derivatization. Thermal decomposition at T2 = 90 °C showed high selectivity for α-olefins in the oil (90.1 mol% α-olefins and 9.9 mol% internal olefins) compared to the wax (78.7 mol% α-olefins and 21.3 mol% internal olefins) (Table 10). This high selectivity for terminal olefins in the oil is likely due to extensive β-cleavage, which shortens the product chain length and statistically promotes terminal olefin formation. This hypothesis is supported by GPC and HT-GPC data, which show a number-average molar mass of ~180 g / mol for the oil and 380 g / mol for the wax. Figure 33 (and Table 11). Notably, the synthetically useful α-olefins in the thermal decomposition oil consist primarily of hydrocarbons in the diesel range, opening up opportunities for alternative fuel applications. Conversely, thermal decomposition at T2 = 28 °C results in lower α-olefin yields, likely due to fewer β-fracture events resulting from the relatively short residence time at the bottom of the reactor (Table 10).

[0259] Polypropylene and blended plastics Crushed PP was loaded into a reactor and subjected to thermal decomposition under two different heating gradients. Similar to HDPE, wax was the major product at T2 = 28 °C (Figure 24A, center). By increasing T2 to 90 °C, thermal decomposition oil became the major product with a yield of 62%, similar to previous studies conducted at comparable temperatures.

[24] (Figure 24A, center “PP product at 90°C”). Degradation in the oil fraction yielded 32.4 mol% 2,4-dimethyl-1-heptene (Figure 24C), which is the trimer fragment (C9) reported in previous PP pyrolysis studies. [25-26] Up to 38 wt.% of the polymer was converted into gaseous products, which may be due to the easily degradable branched tertiary fibers of PP. Structure. The gas phase mainly consists of acyclic compounds, including... E -2-Butene, pentane and 2-methyl-1-pentene ( Figure 34 Cyclopropane was the only gaseous cycloparaffin detected by GC-MS. Finally, after complete degradation of PP within 2 h, no wax was collected from the reactor. GC confirmed a narrow product distribution in the oil, primarily consisting of ≤C20 light hydrocarbons (Figure 24C). Furthermore, GPC and HT-GPC results validated the overall decrease in product molar mass with increasing T2, showing an average molar mass of wax of ~570 g / mol and an average molar mass of oil of ~250 g / mol. Figure 33 In summary, these results support the feasibility of altering the temperature gradient in regulating the degree of chain breakage during the thermal decomposition of polyolefins.

[0260] Similar to the thermal decomposition of PE, the alkenyl concentration (C) of PP-oil C=C The alkenyl concentration of PP-oil was significantly higher than that of wax produced at T2=28℃ (7.08 mmol / g for PP-oil at -90℃, and 4.61 mmol / g for PP-wax at -28℃, Table 10). The C content in PP-oil... C=C C higher than PE C=C This stems from the thermodynamic stability of carbon-centered group intermediates due to the substitution of methyl groups on every second carbon.

[27] Therefore, in addition to adjusting the molar mass of the thermal decomposition products, different heating gradients also serve the dual purpose of increasing the concentration of olefin groups. Interestingly, most of the olefins in PP oil are acyclic α-olefins. 1 H NMR showed no signal in the typical range of internal olefins (above 5.0 ppm). Figure 35 Furthermore, GC-MS confirmed the dominance of α-olefins, as the strongest peaks in the chromatograms corresponded to 2,4-dimethyl-1-heptene (1), 2,4-dimethyl-1-decene (5), and 4,6,8-trimethyl-1-nonene (7). Figure 36 Compared to PE-derived oils, trace amounts of cyclic products, including 1,3,5-trimethylcyclohexane, were detected in PP thermal decomposition oils, indicating some intramolecular group recombination. Figure 36 and Figure 24B (middle). Nevertheless, acyclic olefins and alkanes make up the majority of PP thermal decomposition oil.

[0261] Real-world plastic waste is a complex mixture of many polymers. To test the ability to convert plastic mixtures into value-added products, the applicant thermally decomposed PE with varying amounts of PP. PE / PP mixtures were an interesting choice because the two polyolefins are difficult to separate from each other due to their comparable density and chemical composition.

[28] A mixture of 25 wt.% HDPE (milk jugs), 25 wt.% LDPE (sample container caps), 25 wt.% LLDPE (commercial grade), and 25 wt.% PP (laboratory centrifuge tubes) was exposed to two thermal decomposition conditions. A high wax yield of 87 wt.% was obtained at a reaction condition of T2 = 28 °C, while a yield of 54 wt.% oil as the major product was provided at a reaction condition of T2 = 90 °C (Figure 24A, right). The gas phase at T2 = 90 °C comprised ~27 wt.% of the product and contained light olefins, including propylene and... E -2-Butene and small amounts of ≥C5 alkanes ( Figure 37As determined in the case of single polymer thermal decomposition, increasing the temperature of the condensation zone generally shifts the product distribution to a lower molar mass state. Figure 24D GPC and HT-GPC data further support this observation, showing the waxes derived from the plastic mixture. M n (~244 g / mol) higher than oil's ~200 g / mol ( Figure 33 ).

[0262] Structural analysis revealed a combination of characteristics of the products from the thermal decomposition of PE and PP. In addition to linear alkanes, alkenes, and dienes from the thermal decomposition of the PE component, methyl-substituted acyclic alkanes and terminal alkenes were detected by GC-MS, consistent with the fragmentation of PP compounds. Figure 38 Products 2, 3, 4, 6, 7, and 8). Furthermore, the presence of PP leads to the formation of small amounts of cycloalkanes in the oil phase, such as 1,3,5-trimethylcyclohexane (5). Figure 38 Compared to pure HDPE oil, the mixed plastic waste exhibited higher selectivity (93.4%) for α-olefins in the oil fraction, likely due to the excellent selectivity of PP for terminal olefins (Table 10) after introduction. On the other hand, the thermal decomposition of the same mixed feedstock at T2 = 28°C provided 84.4% α-olefins in the wax. 1 H-NMR (Figure 39A). As mentioned above, the inconsistency in the selectivity of the two thermal decomposition conditions for α-olefins is attributed to the difference in the degree of chain scission that produces olefin-rich hydrocarbons.

[0263] Upgrade to sulfate detergent PE and PP oils can be further functionalized to produce fatty acids, alcohols, and sulfonic acids and their corresponding salts. In the current study, given the high demand and market value of soap and detergent products, the applicant has identified them as targets. Figure 23E As a proof-of-concept for adding value to plastic waste, PE and PP thermal decomposition oils are converted into ionic detergents in a two-step process. First, the cooling oil in a cold bath is reacted with concentrated sulfuric acid to produce alkyl bisulfates. The bisulfates are then neutralized with an aqueous solution of potassium hydroxide (KOH, 1 M) to produce the ionic detergent (Figure 5A). Adding H₂SO₄ to the PE-oil converts all α-olefins to alkyl bisulfates, such as… 1 The disappearance of the olefin peaks at 4.90–5.04 ppm and 5.82 ppm in the ¹H NMR spectrum proves that ( Figure 5B ). In 2D 1 H- 13In CHSQC NMR, two new resonance peaks at 4.71 ppm and 4.82 ppm (attributed to the Markovnikov and anti-Markovnikov products, respectively) correlated with carbon signals between 84.50 and 88.37 (Figure 5C). Unlike the α-olefin group, the minor internal olefin (9.9 mol%) in the PE oil was unaffected by the sulfation reaction, likely due to the mild reaction conditions employed. However, since olefin groups are present in many surfactant compounds and are beneficial for foaming and moisturizing properties,

[29] The applicant did not pursue further sulfation of the residual olefin groups. The sulfation reaction effectively converted both PP-oil and PE / PP-oil into their corresponding alkyl bisulfates (symbols SX and SY). However, unreacted internal olefin groups from thermal decomposition were detected in both 1D NMR and HSQC (6.6 mol%) in the mixed oil. Finally, the alkyl bisulfates were neutralized and alkalized with KOH until the pH reached ~9 before further characterization.

[0264] The properties of detergents were studied using various instruments and techniques. The wettability of soaps and detergents determines the extent to which their solutions spread on a substrate surface. To determine wettability, the applicant measured the contact angles on hydrophobic surfaces at a range of detergent concentrations from 0 g / L to 6.25 g / L. Hydrophobic surfaces were created by wrapping a strip of paraffin film around a glass slide (Figure 26A). For all PE-detergents, PP-detergents, and PE / PP-detergents, the contact angle decreased with increasing detergent concentration. Figure 26B Compared to the mixed and PP counterparts, PE detergents exhibit superior wetting properties. Figure 26C The improved wettability is attributed to the favorable interaction between the alkyl chains of the detergent and the hydrophobic paraffin film chains at the interface. Conversely, the binding of methyl-substituted chains (primarily short-chain 2,4-dimethyl-1-heptene) in the PP-oil hinders the same interchain interaction, likely due to poor chain flexibility.

[30] Therefore, the introduction of PP-derived molecules into mixed detergent formulations slightly worsens the wetting properties. Figure 26B (Red curve). However, it maintained sufficient wettability under low PP weight loads not exceeding 10 wt.% (Figure 40).

[0265] PE-derived and PE / PP-derived ionic detergents exhibited excellent foaming behavior and emulsifying ability at room temperature. PE-detergent showed sustained good foaming over a period of 1 hour. Figure 27A (line 1). In contrast, detergents containing PP cannot maintain stable foam formation ( Figure 27A(Lines 2 and 3), presumably due to the defoaming properties of the branched chain.

[31] Nevertheless, the low-foaming characteristics of PP detergents can be used to formulate PE / PP blended surfactants, which exhibit excellent wetting and defoaming properties for industrial applications.

[32] Furthermore, an effective detergent should have an affinity for both water and organic matter to achieve amphiphilic (i.e., hydrophilic and lipophilic) properties. To determine the emulsifying ability of detergents derived from plastic waste, the separation time of 10 mL of water from a paraffin oil-water mixture was recorded. Figure 41 ).

[33] In the absence of detergent, separation was rapid, with 10 mL of water separating from the mixture in 21 s (Figure 27B). Adding PP-detergent and PE-detergent at concentrations of 1.25 mg / mL significantly extended the emulsification time to 91 s and 186 s, respectively. Notably, the PE / PP-detergent also exhibited excellent emulsifying properties comparable to pure PE-detergent, demonstrating the feasibility of converting unsorted mixed polyolefin waste into sustainable emulsifiers. In addition to paraffin oil, the detergent solution (1.2 mL) was thoroughly mixed with 50 μL of hexane, further confirming their excellent emulsifying properties. Figure 42 ).

[0266] To investigate the ability of detergents to reduce the surface tension (γ) of water, the applicant prepared a series of detergent solutions with different concentrations and measured γ using a theta flow tensiometer in endant drop mode. PE-detergent resulted in the highest reduction in γ at the air-water interface, reaching a critical micelle concentration of 45.5 mN / m (γ). CMC =45.5 mN / m, CMC=241 mg / L, Figure 27C). Due to poor hydrophobicity and aggregation of short alkyl chains, PP-detergent exhibits minimal γ-change at low detergent concentrations and only undergoes micellization (γ-) at higher concentrations. CMC =51.6 mN / m, CMC=518 mg / L (Figure 43A).

[34] For this reason, the inclusion of 25 wt.% PP in the PE / PP blend precursor results in a CMC value of 389 mg / L for the PE / PP detergent and γ CMC 49.3 mN / m Figure 27D The concentration of γ was higher than that of pure PE-detergent. Nevertheless, comparable to pure PE-detergent, detergents derived from mixed PE / PP waste containing up to 10 wt.% PP still exhibited a high reduction in γ at a relatively low CMC of 238 mg / L. CMC =48.4)( Figure 43BThis indicates the latter's ability to tolerate "polymer impurities." Compared to some benchmark detergents such as sodium dodecyl sulfate (CMC > 2 g / L)...

[35] In comparison, PE-derived detergents and PE / PP blend-derived detergents have relatively low CMC, indicating that they have excellent performance even at low concentrations.

[0267] discuss Custom-designed quartz reactors with cooling zones enable the synthesis of valuable hydrocarbons for a variety of downstream applications, such as detergents. The hydrogen-free and catalyst-free process is actually superior to conventional hydrocracking strategies because olefin intermediates can be readily chemically converted into high-value products. [36-37] Furthermore, saturated byproducts can undergo oxidation in the presence of inorganic catalysts or microorganisms to form useful value-added chemicals. [38-39] In addition, relatively mild thermal decomposition reaction conditions are key to avoiding the formation of low-value coke, which is reported to form at temperatures above 450°C.

[40] The applicant anticipates increasing the yield of thermally decomposed oil by utilizing a reactor with sufficient headspace to accumulate the total volume of oil. In addition to producing detergents and surfactants, PE and PP thermally decomposed oils can be used as diesel fuel after hydrogenation.

[41] It is worth noting that the cycloalkanes observed in PP-oil are permitted in diesel formulations, and they can account for ~40% of the total composition.

[42] Future research will explore the possibility of targeting terminal alkyl sulfates specifically in upgraded cyclic reactions. Specifically, α-olefins in plastic-derived oils can be converted to primary fatty alcohols via hydroboration, followed by sulfonation with an air / SO3 mixture (see preliminary results for fatty alcohol synthesis). Figure 20 Nevertheless, a considerable trade-off is required because this approach involves more synthetic steps, thus potentially increasing the cost of large-scale production.

[0268] Opinion Despite the continued accumulation of single-use plastics in the environment over the past six decades, concerted efforts are underway to curb this pollution problem. Among the most promising approaches, utilizing plastic waste as a raw material to produce a variety of useful chemicals and products has shown significant success. The method presented in this paper utilizes this underutilized resource to generate high-value detergents. The use of a coolant (e.g., water) to regulate the temperature gradient effectively modulates the total molar mass of the intermediate hydrocarbon products, enabling the final production of thermally decomposed oils instead of waxes. To further enhance the intermediate's value, the olefin-rich oil is reacted with sulfuric acid to provide an ionic detergent. Ultimately, this work highlights a viable chemical strategy for obtaining essential high-value products from plastic waste while contributing to the goals of a circular economy.

[0269] experiment Material Deuterated benzene (C6D6, 99.8%, Cambridge Isotope Laboratories, Inc.), sulfuric acid (98.0%; Fisher Scientific), hexane (≥98.5%; VWR Chemicals), and potassium hydroxide (pure granules; Sigma-Aldrich) were purchased and used without further purification. HDPE (milk jug), LDPE (sample container caps), and i PP (centrifuge tubes) were locally obtained in Blacksburg, VA. They were washed and air-dried before pulverization. LLDPE granules (commercial grade) were used without further purification. All polymers were heated in Homeland before thermal decomposition. ® Grind into powder in a grinder for 15 minutes (5 minutes, 3×).

[0270] instrument GC-FID. GC analysis was performed on a 5890 Series II gas chromatograph equipped with a DB-5 capillary column (30 m × 0.25 mm × 0.25 μm) and a flame ionization detector (FID). The following conditions were applied: helium column flow rate, 11 ml / min; injector temperature, 280 °C; detector temperature, 280 °C; initial column temperature, 50 °C; heating rate, 10 °C / min; final column temperature, 280 °C.

[0271] GC-MS. All GC-MS analyses were performed using a 6890 linked to a 5973 MSD from Agilent (Wilmington, DE). Separates were obtained using a DB-5 column (30 m, 250 µm ID, membrane thickness 0.25 µm). The following operating conditions were used for the analyses:

[0272] HT-GPC. HT-GPC was performed using a Tosoh EcoSec HLC-8321 high-temperature GPC system equipped with a refractive index (RI) detector at 160 °C (for polymers and 50 °C for waxes) at a sample flow rate of 1.0 mL / min and a reference flow rate of 0.5 mL / min. The mobile phase was 1,2,4-trichlorobenzene (TCB, Fischer Scientific-HPLC grade). Polymer separation was performed using four Tosoh TSKgel columns attached in the following order: 1 × TSKgel guard column HHR (30) HT2 7.5 mm I.D. × 7.5 cm. (PN 22891), 2 × TSKgel G2000 HHR (20) HT2 7.8 mm ID × 30 cm column (PN 22890), and 1 × TSKgel GMH HR-H (S) HT2 7.8 mm ID × 30 cm column (PN 22889).

[0273] Lignin-GPC. Dissolve 15-20 mg of sample in THF to achieve a concentration of ~2 mg / mL and stir for 30 min. Filter the THF solution through a 0.2 μm syringe filter into an HPLC vial. Inject 20 µL of sample into an HPLC system equipped with three PLgel 7.5 × 300 mm tandem columns: 10 µm × 50 Å, 10 µm × 10³ Å, and 10 µm × 10⁴ Å (Agilent Technologies, Stockport, UK), and run at ambient temperature with isocratic chromatography at 1 mL / min. -1 100% tetrahydrofuran (Sigma-Aldrich, inhibitor-free, suitable for HPLC ≥99.9%) was used for 40 minutes. Analytes were monitored at 210 nm, 260 nm, and 270 nm using a diode array detector.

[0274] NMR. All 1 All 1H NMR experiments were performed at 298 K on a 500 MHz Bruker Avance II 500 spectrometer with 16 scans. All spectra were recorded using deuterated benzene and chloroform. Oil 13 C10 NMR experiments were performed at 298 K on a 500 MHz Bruker Avance II 500 spectrometer using a 2 s relaxation delay and 1024 scans. Alkyl hydrogen sulfates were analyzed using a 6 s relaxation delay and 3072 scans.13 2D-HSQC was performed at 298 K on a 500 MHz Bruker Avance III 500 spectrometer with a relaxation time of 2 s, 16 scans, and a digitization increment of 400.

[0275] Theta flow tensiometer. Contact angle and surface tension measurements were performed at room temperature on a Biolin Scientific theta flow tensiometer. Contact angle experiments were conducted in seated drop mode with a droplet volume of ~5 µL, a droplet rate of 1 µL / s, and a run time of ~10 s. Surface tension measurements were evaluated in pendant drop mode with a droplet volume of ~10 µL, a droplet rate of 1 µL / s, and a run time of ~10 s.

[0276] Thermal decomposition process Typically, 1.5 g of pulverized HDPE (particle size, 2.7 mm) or PP (particle size, 1.6 mm) is loaded into a custom-designed quartz reactor and purged with nitrogen at 200 °C for 15 min. After purging, the temperature is slowly increased (rate, 20 °C / min) to the operating temperature range (~400 °C at the bottom of the reactor and ~360 °C at the top of the plastic melt). Simultaneously, room temperature or heated water is circulated in the reactor's external jacket. After 10 min, the cold zone temperatures stabilize at ~28 °C and ~90 °C, respectively. Thermal decomposition of HDPE lasts for 6 h, and thermal decomposition of PP lasts for 2 h. Upon completion, the thermally decomposed oil in the headspace is collected using a glass pipette and weighed on an analytical balance. The solid wax is extracted twice from the reactor with hexane (10 ml each time), dried under vacuum, and weighed to determine the yield.

[0277] To upgrade the recycling of PE-oil and PP-oil into sulfate detergent, 100 mg of each oil was weighed and transferred to a flame-dried 25 ml vial equipped with a stir bar. The vial was placed in a cold bath at 0°C, and 50 mg of concentrated sulfuric acid was added dropwise while stirring. After 10 min, the vial and its contents were stirred at room temperature for another 10 min and neutralized with 1 M KOH solution (1.2 ml) to provide an ionic detergent. The detergent solution was diluted to 8 ml of DI water. The unconverted alkane fraction was separated by washing the crude solution with 15 ml of hexane (5 ml, 3×). The combined hexane extract was dried over Na2SO4, concentrated under vacuum, and weighed. A small sample was then taken for GC and GC-MS characterization. To remove residual hexane from the purified detergent solution, a moderate vacuum of 300 mmHg was applied to the detergent vial at 45°C.

[0278] Additional Information Supplementary discussion The global detergent market is currently worth more than USD 120 billion annually, and demand is expected to continue to grow in the coming decades. [1] Aside from animal fats and oleochemicals, a large portion of detergents are made from petrochemical products (up to 44%). [2] Therefore, several environmental and ecological damages are associated with the production of surfactants and detergents. These environmental and ecological damages include deforestation and increased global greenhouse gas emissions due to the consumption of large amounts of petrochemical products in production operations. [3-4] Therefore, industries are encouraged to integrate renewable resources and raw materials into their processes to reduce their carbon footprint. In recent years, alternative detergents have been produced from sustainable resources. However, to significantly improve the sustainability of the detergent and soap industry, there is an urgent need for new, scalable processes that rely on widely available and inexpensive raw materials.

[0279] The method proposed in this paper generates ionic detergents from real-world plastic waste in 6 hours or less without using any catalysts or solvents. Specifically, M w PE and PP plastics ranging from 35.3 kDa to 146.7 kDa (Table 3) are first degraded and converted into saturated and unsaturated oils. Importantly, the temperature of the coolant is key to controlling the ratio of oil to wax produced. Notably, water at temperatures between 28°C and 90°C can effectively regulate this ratio, eliminating the need to purchase expensive coolant fluids. Therefore, unlike other batch reactors used in pyrolysis technology, the design of the condenser not being separated from the reactor allows for control over the molar mass of the products.

[0280] Through C6D6 containing a known amount of residual C6H6 1 H NMR experiments were used to assess the concentration of alkenyl groups in both the oil and wax (Figure 30). Figure 35 (and Figure 39). The alkenyl concentration was determined based on the following equation by setting the C6H6 signal as an internal standard (and Figure 39). C C=C ):

[0281] Where m 溶剂 It is the mass of the solvent; M 溶剂 It is the molar mass of C6D6; f It is the mass fraction of conventional benzene in deuterated benzene; n ref-H It is the number of hydrogen atoms on the solvent molecule (n) ref-H =6); r is the NMR integral ratio of the alkenyl group relative to C6H6; n ene-HIt is the number of hydrogen atoms on the alkenyl group (n for terminal alkenes). ene-H =3); and m is the mass of the sample. In all cases, oils from thermally decomposed plastics exhibited a higher concentration of olefin groups compared to waxes. The applicant speculates C C=C The difference can be attributed to the variation in the degree of chain breakage induced by the polymer under the two thermal decomposition conditions. In other words, the hydrocarbons vaporized during thermal decomposition condense and then melt when they reach the condensation zone at T2 = 90°C (melting point of PE wax = 68.8°C-80.1°C). Finally, the molten products return to the bottom of the reactor at T1 = 360°C-400°C, where the chain breakage process continues.

[0282] The olefinic components of the oil were functionalized by sulfation with concentrated sulfuric acid (concentrated H₂SO₄) at mild temperatures. Concentrated H₂SO₄ is a widely available and inexpensive chemical ($146 / ton), and therefore a practical choice for large-scale upgrades in the cycle. The resulting alkyl hydrogen sulfate was neutralized using an aqueous KOH solution to form a sulfate detergent. Notably, the alkane components were unaffected by the sulfation conditions and could be extracted by washing the crude product with hexane. GC-MS confirmed that the extract mainly contained ~C7 to C6. 26 Saturated hydrocarbons within the range (Figure 44-) Figure 47 Therefore, the unreacted fractions of thermally decomposed oils can be used as alternative fuels without additional hydrogenation treatment.

[0283] Table 9. Distribution of hydrocarbon products from previous reports and this work.

[0284]

[0285] a Carbon number range of oil grades Table 10. Alkenyl group concentration in the thermal decomposition products of plastics. (Used using the internal standard method) 1 Concentration was assessed using 1H NMR.

[0286]

[0287] Table 11. Characterization of molar mass of thermal decomposition products obtained from plastic waste. Both lignin-GPC and HT-GPC were used to determine molar mass.

[0288]

[0289] Table 12. Characterization of the molar mass of the plastics used in the degradation experiments. The study was conducted using HT-GPC.

[0290]

[0291] References Unless otherwise specified in this disclosure, references cited in this disclosure are listed below. References in this document may be cited using the format of reference numbers enclosed in parentheses, corresponding to one or more of the following numbered references. References may also be cited using superscript format in this document. For example, the citations of reference numbers 1 and 2 immediately following below may be indicated in this disclosure as (References 1 and 2) or as the superscript "". 1-2 ".

[0292] All publications and patents referenced in this specification are cited to disclose and describe methods and / or materials in relation to the cited publications. All such publications and patents are incorporated herein by reference as if each individual publication or patent were specifically and individually indicated to be incorporated by reference. Such incorporation by reference is expressly limited to the methods and / or materials described in the cited publications and patents and does not extend to any dictionary definitions from the cited publications and patents. Any dictionary definitions in the cited publications and patents that are not expressly repeated in this specification should not be treated as such and should not be construed as defining any terms appearing in the appended claims. Furthermore, any patent and patent application claiming priority by reference is not intended to extend to any dictionary definitions in such incorporated patent and patent application and should not be construed as limiting the appended claims.

[0293] References to any publication refer to its publication prior to the filing date and should not be construed as an admission that this disclosure is not entitled to precede such publication due to prior disclosure. Furthermore, the date provided for a publication may differ from the actual publication date, which may require independent verification.

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N.; Shi,R.; Wen, X.; Zhang, T., Manganese Oxide Modified Nickel Catalysts forPhotothermal CO Hydrogenation to Light Olefins. Advanced Energy Materials 2019, 10 (5). (45) Puglisi, A.; Mondini, S.; Cenedese, S.; Ferretti, A. M.; Santo,N.; Ponti, A., Monodisperse Octahedral α-MnS and MnO Nanoparticles by theDecomposition of Manganese Oleate in the Presence of Sulfur. Chemistry of Materials 2010, 22 (9), 2804-2813. References for supporting information in Example 1

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[0296] References for Example 2

[0297]

[0298]

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[0300] References for supplementary information in Example 2

[0301] It should be emphasized that the aspects described above in this disclosure are merely possible examples of implementation methods and are only presented for the purpose of clearly understanding the principles of this disclosure. Many variations and modifications can be made to the aspects described above without departing substantially from the spirit and principles of this disclosure. All such modifications and variations are intended to be included within the scope of this disclosure. It is intended that the specification and embodiments be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A method for preparing waxes and / or oils from olefin-derived products, comprising: Heating a polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof in a container in fluid communication with a condenser to provide a mixture of sublimated wax and / or oil collected on the condenser or thermal control system, wherein the heating comprises raising the temperature of the container to a target temperature for a first time period and maintaining the container at or near the target temperature for a second time period to provide the mixture of wax and / or oil.

2. The method of claim 1, wherein raising the temperature of the container comprises heating it at a rate of about 10°C to about 30°C per minute during the first time period.

3. The method according to claim 1 or 2, wherein the second time period is 1 hour to 48 hours, 1 hour to 24 hours, 1 hour to 20 hours, or 5 hours to 20 hours.

4. The method of claim 1, wherein raising the temperature of the container comprises heating the bottom of the container to the target temperature in three steps at a increment of about 80°C to about 120°C every 5 minutes.

5. A method for preparing a mixture of waxes and / or a mixture of oils, comprising: A polymer selected from the group consisting of polypropylene, polyethylene, and combinations thereof is introduced into a continuous flow reaction vessel in fluid communication with a condenser or heating control system to provide a mixture of sublimated waxes and / or oils collected on the condenser or heating control system, wherein the continuous flow reaction vessel is at or near a target temperature, and wherein the polymer has a residence time in the continuous flow reaction vessel to provide a mixture of waxes and / or oils.

6. The method according to claim 1 or 5, wherein the stay time is 1 hour to 48 hours, 1 hour to 24 hours, 1 hour to 20 hours, or 5 hours to 20 hours.

7. The method according to claim 1 or 5, wherein the target temperature is about 250°C to 500°C.

8. The method according to claim 1 or 5, wherein the target temperature is 260°C to 490°C, 270°C to 480°C, 290°C to 460°C, 310°C to 440°C, 330°C to 420°C, 350°C to 400°C, or 370°C to 380°C.

9. The method according to claim 1 or 5, wherein the target temperature is about 320°C to 350°C.

10. The method according to claim 1 or 5, wherein the target temperature is 320°C to 400°C, or 340°C to 380°C, or 320°C to 370°C, or 330°C to 360°C.

11. The method of claim 1 or 5, wherein the polymer is exposed to ambient air.

12. The method of claim 1 or 5, wherein the polymer is exposed to an inert gas in the container.

13. The method of claim 12, wherein the inert gas is nitrogen or argon.

14. The method of claim 1 or 5, wherein the polymer is exposed to oxygen mixed with an inert gas in the container.

15. The method of claim 1 or 5, wherein the polymer is exposed to air mixed with an inert gas in the container.

16. The method according to claim 1 or 5, wherein the container is heated at atmospheric pressure.

17. The method according to claim 1 or 5, wherein the polymer is selected from the group consisting of cross-linked polypropylene, cross-linked polyethylene, linear polypropylene, linear polyethylene, and combinations thereof.

18. The method according to claim 1 or 5, wherein the polymer is selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polyethylene copolymer, polypropylene copolymer and high-density cross-linked polyethylene.

19. The method according to claim 1 or 5, wherein the percentage mass conversion of the polymer to the mixture of the wax is about 85% to 99%, or about 85% to 95%, or about 85% to 90%, or about 90% to 95%.

20. The method according to claim 1 or 5, wherein the temperature difference between the container and the condenser surface is about 300°C to 400°C or about 325°C to 375°C.

21. The method according to claim 1 or 5, wherein the target temperature is about -195°C to 250°C.

22. The method according to claim 1 or 5, wherein the condenser surface has a temperature of -185°C to 240°C, -175°C to 230°C, -165°C to 220°C, -155°C to 210°C, -145°C to 200°C, -135°C to 190°C, -125°C to 180°C, -115°C to 170°C, -105°C to 160°C, -95°C to 150°C, -85°C to 140°C, -75°C to 130°C, -65°C to 120°C, -55°C to 110°C, -45°C to 100°C, -35°C to 90°C, -25°C to 80°C, -15°C to 70°C, -5°C to 60°C, 5°C to 50°C, 15°C to 40°C, or 25°C to 30°C.

23. The method according to claim 1 or 5, wherein the container, the condenser, or both comprise a quartz surface.

24. The method according to claim 1 or 5, wherein, based on the total weight of the mixture of waxes and / or the mixture of oils, the wt% of light hydrocarbons having 8 or fewer carbon atoms in the mixture of waxes and / or the mixture of oils is about 10 wt%, 8 wt%, 5 wt%, or less.

25. The method according to claim 1 or 5, wherein the method further comprises adding sulfuric acid to the mixture of the wax and / or the mixture of the oil.

26. The method according to claim 1 or 5, wherein the mixture of waxes and / or the mixture of oils independently have hydrocarbon lengths of C7-C26 and are acyclic, cyclic, or a combination thereof.

27. The method according to claim 1 or 5, wherein the mixture of waxes and / or the mixture of oils are independently unsaturated hydrocarbons, saturated hydrocarbons, or combinations thereof.

28. The method according to claim 1 or 5, wherein the method further comprises neutralization.

29. The method of claim 28, wherein neutralization comprises adding sodium hydroxide or potassium hydroxide.

30. The method of claim 1 or 5, wherein the condenser includes liquid circulation, optionally wherein the liquid is water, glycol, mineral oil, dielectric fluid or a combination thereof.

31. The method according to claim 1 or 5, wherein the wax and / or oil is further hydrogenated or borohydride-treated.

32. The method according to claim 1, 5, 25, 28 or 29, further comprising blending the mixture of fatty acids with a base to provide a mixture of fatty acid carboxylates.

33. The method according to claim 1, 5, 25, 28 or 29, further comprising treating the mixture of said fatty acid carboxylates with acid to provide a purified mixture of fatty acids.

34. The method according to claim 1 or 5, wherein the alkyl carboxylic acid manganese is added to the mixture of the wax and / or the mixture of the oil.

35. The method of claim 34, wherein the alkyl carboxylic acid manganese is manganese stearate.

36. The method according to claim 1 or 5, wherein the alkyl carboxylate is selected from the group consisting of C12-C24-alkyl carboxylates and combinations thereof.

37. The method according to claim 1 or 5, wherein the mixture of waxes and / or the mixture of oils comprises waxes with an average carbon chain length of about C18 to C47, wherein the mixture of fatty acids comprises fatty acids with an average carbon chain length of about C18 to C47, or both.

38. The method according to claim 1 or 5, wherein the w / w ratio of the mixture of alkylcarboxylic acid manganese and the wax is from about 0.001 to about 0.10.

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