Cobalt and / or cerium-doped zeolites for bifunctional catalytic hydroisomerization

Abstract

This document provides a method for the hydroisomerization of hydrocarbon feedstocks, the method comprising contacting the hydrocarbon feedstock with hydrogen and a catalyst to produce a hydrocarbon product having an increased number of branched hydrocarbons relative to the hydrocarbon feedstock. The catalyst of this invention comprises heteroatom-doped β-zeolite having a trivalent cation as a framework metal oxide, an extra-framework species consisting of cerium and / or cobalt, and 0.01 wt% to 1.5 wt% of a Group VIII or Group VIB metal, or a combination thereof.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority and interest in U.S. Application No. 17 / 349989, filed June 17, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to the hydroisomerization of light alkanes, and more specifically, to novel catalysts for carrying out the hydroisomerization of light alkanes. Background Technology

[0004] Hydroisomerization of light straight-chain alkanes is a primary reaction that utilizes certain petroleum resources to increase the octane number of gasoline fuel products. Zeolite catalysts have been employed for this purpose. However, zeolite-based hydroisomerization catalysts for light alkanes experience a side reaction known as cracking. Due to the high activity and selectivity of metal oxide catalysts for the hydroisomerization of light straight-chain alkanes, metal oxide catalysts have been developed for these reactions. However, the presence of toxic substances such as S, N, H₂O, and Cl can reduce the activity of the catalysts. Summary of the Invention

[0005] This document provides a method for the hydroisomerization of hydrocarbon feedstocks, the method comprising contacting the hydrocarbon feedstock with hydrogen and a catalyst to produce a hydrocarbon product having an increased number of branched hydrocarbons relative to the hydrocarbon feedstock. The catalyst of this invention comprises heteroatom-doped β-zeolite, the heteroatom-doped β-zeolite comprising a trivalent cation as a framework metal oxide, an extra-framework species consisting of cerium and / or cobalt, and 0.01 wt% to 1.5 wt% of a Group VIII or Group VIB metal, or a combination thereof.

[0006] This article also provides a method for synthesizing heteroatom-doped β-zeolites containing cerium or cobalt as extra-skeletal species. The method involves crystallizing a reaction mixture containing water, SiO2, and a framework metal oxide (i.e., a reaction mixture suitable for synthesizing β-zeolites, particularly aluminum-containing β-zeolites) in the presence of a cerium and / or cobalt source. The reaction mixture comprises: a molar ratio of structure-directing cation Q to SiO2 of 0 to 4; a molar ratio of SiO2 to framework metal oxide greater than 10; a molar ratio of water to SiO2 greater than 0; a molar ratio of alkali metal M to SiO2 of 0.1 to 1; and a molar ratio of SiO2 to Al source greater than 5. Cerium and / or cobalt are added to the reaction mixture prior to crystallization, for example, in the form of cerium salts and / or cobalt salts. The method for synthesizing heteroatom-doped β-zeolites of the present invention includes the step of calcining the heteroatom-doped β-zeolite, wherein the framework heteroatoms are converted into extra-skeletal species under inert, oxidizing, and / or steaming conditions at a temperature of 100°C to 800°C. The reaction mixture may also contain mineralizers and / or structure-directing agents.

[0007] These and other features and properties of the methods and compositions disclosed herein, and their advantageous applications and / or uses, will become clear from the following detailed description. Attached Figure Description

[0008] To assist those skilled in the art in making and using the subject matter of this invention, please refer to the accompanying drawings, in which:

[0009] Figure 1 This is an X-ray diffraction pattern of Ce-doped Al-β zeolite (top line) relative to Al-β zeolite (bottom line).

[0010] Figure 2 These are DR UV-vis images of Ce-doped Al-β zeolite reference CeO2 before and after calcination (the signal was reduced to 1 / 20 for visual clarity).

[0011] Figure 3 The isomerization selectivity (%) of heteroatom-doped zeolites at 230 °C relative to the n-heptane conversion (%) is shown, where WHSV is equal to 2 / h, 4 / h, and 6 / h.

[0012] Figure 4 The isomerization selectivity (%) of heteroatom-doped zeolites at 250 °C relative to the n-heptane conversion (%) is shown, where WHSV is equal to 2 / h, 4 / h, 6 / h or 4 / h, 6 / h.

[0013] Figure 5AThe results show the RON increment relative to the weight % of light gases (C1 to C4) formed at 250 °C, and the LHSV at 250 °C is equal to 3 / h and 6 / h. Results for the catalyst Pt / Fe / WZrOx operating at 170 °C are also presented.

[0014] Figure 5B This is a graph showing the n-C7 conversion rate relative to the formation of light gases due to cracking.

[0015] Figure 6 The relative conversion levels of n-C6 and n-C7 of the four catalysts described in Example 3 are shown at 250 °C with LHSVs of 3 / h and 6 / h. Results for the Pt / Fe / WZrOx catalyst at 170 °C are also shown.

[0016] Figure 7 The results show that at 230°C with a WHSV of 0.75h... -1 1h -1 1.5h -1 Isomer selectivity relative to conversion rate. Detailed Implementation

[0017] Unless otherwise specified in this specification, the singular forms “a,” “an,” “the,” and “the” used in this disclosure and claims include the plural forms.

[0018] As used in phrases such as “A and / or B” in this article, the term “and / or” is intended to include “A and B”, “A or B”, “A”, and “B”.

[0019] Term "C" n "Carbon compounds containing carbon atoms, having a total of n carbon atoms in their molecular structure, or a mixture of two or more such hydrocarbon compounds. These hydrocarbons may contain varying degrees of unsaturated carbon."

[0020] The terms "alkanes," "alkane," and "saturated hydrocarbons" are used interchangeably in this document and refer to hydrocarbons with the chemical formula C10, C20, C30, C40, C50, C60, C7 ...70, C70, n H 2n+2 Hydrocarbons.

[0021] The terms “straight-chain” and “normal” are used interchangeably in this document and refer to hydrocarbons without side chain branches.

[0022] The term "cracking" refers to the transformation of a given hydrocarbon molecule into two smaller hydrocarbon molecules.

[0023] The terms "isomerization" and "hydroisomerization" refer to the skeletal rearrangement of hydrocarbons, particularly the conversion of n-chain alkanes into branched chain alkanes.

[0024] The term “weight time space velocity” (“WHSV”) refers to a measure of the flow rate of the feed mixture per unit weight of catalyst per hour.

[0025] The term “liquid time space velocity” (“LHSV”) refers to a measure of the volume of the feed mixture per hour per unit volume of catalyst.

[0026] The term "variable oxidation state metal" refers to a metal that has two or more accessible oxidation states that are not zero.

[0027] The term "total surface area" refers to the total specific external surface area and specific internal surface area of ​​a dispersed or porous solid (microporous material), obtained by measuring the amount of adsorption / desorption isotherms of N2 as specified in ISO 9277.

[0028] Unless otherwise specified, the ambient temperature (also known as “room temperature”) is approximately 25°C.

[0029] This document provides a method for the hydroisomerization of hydrocarbon feedstocks, the method comprising contacting the hydrocarbon feedstock with hydrogen and a catalyst to produce a hydrocarbon product having an increased number of branched hydrocarbons relative to the hydrocarbon feedstock. The catalyst comprises heteroatom-doped zeolite β, particularly cerium and / or cobalt-doped β zeolite, 0.01 wt% to 1.5 wt% of Group VIII or Group VIB metals, or combinations thereof, and may also comprise a metal oxide binder. In the method of the present invention, the heteroatom-doped β zeolite comprises a trivalent cation as a framework metal oxide, and an extra-framework species composed of cerium and / or cobalt. The heteroatom-doped β zeolite of the present invention may also comprise a SiO2 to framework / extra-framework oxide molar ratio greater than 10. In one aspect, the heteroatom-doped β zeolite of the present invention comprises a SiO2 to Al2O3 molar ratio greater than 8, particularly greater than 10, such as greater than 10 to 2000 or to 1000, for example 20 to 200, or 30 or 40 to 100 or 150. In one aspect, the heteroatom-doped β-zeolite of the present invention comprises SiO2 with cerium and / or cobalt metal oxides (in the form of CeO2). x or CoO xThe molar ratio of the form of the β-zeolite is greater than 10, such as greater than 10 to 2000 or 15 to 1000, for example 30 or 40 or 50 to 500 or 300. In one aspect, the heteroatom-doped β-zeolite of the present invention comprises a Group VIII or Group VIB metal and / or is selective for the conversion of n-heptane. In one aspect, the present invention therefore relates to the use of cerium and / or cobalt-doped β-zeolite having a trivalent cation (e.g., Al) as a framework metal oxide and an extra-framework species composed of cerium and / or cobalt in a hydroisomerization catalyst, for example for a hydroisomerization method of a hydrocarbon feedstock, the method comprising contacting the hydrocarbon feedstock with hydrogen and the catalyst to produce a hydrocarbon product having an increased number of branched hydrocarbons relative to the hydrocarbon feedstock. The catalyst comprises cerium and / or cobalt-doped β-zeolite, 0.01 wt% to 1.5 wt% of a Group VIII and / or Group VIB metal, particularly Pt, and optionally a metal oxide binder.

[0030] In the hydroisomerization method of the present invention, the hydrocarbon feedstock is contacted with the catalyst under effective isomerization conditions, including an operating temperature of 100°C to 450°C, an operating pressure of 0 psig to 1000 psig, and a working pressure of 0.1 hr. -1 up to 10 hours -1 The WHSV and the hydrogen / hydrocarbon molar ratio are 0 to 100. In one aspect, the catalyst contains 0.1% to 1.5% Pt. The hydrocarbon feedstock comprises any one of the following hydrocarbons: n-pentane, n-hexane, and n-heptane, or combinations thereof.

[0031] As described herein, the method for synthesizing heteroatom-doped β-zeolites containing cerium or cobalt as extra-skeletal species according to the present invention includes the step of crystallizing a reaction mixture containing water, SiO2, and a framework metal oxide (particularly a trivalent framework metal oxide, such as Al). Optionally, the reaction mixture includes a structure-directing agent and / or a mineralizing agent. The reaction mixture comprises: a molar ratio of the structure-directing agent cation Q to SiO2 of 0 to 4; a molar ratio of SiO2 to the framework metal oxide greater than 10; a molar ratio of water to SiO2 greater than 0; a molar ratio of alkali metal M to SiO2 of 0 to 1; and a molar ratio of SiO2 to the Al source greater than 5, such as greater than 10. The method for synthesizing heteroatom-doped β-zeolites according to the present invention includes the step of calcining the heteroatom-doped β-zeolite, wherein the framework heteroatoms are converted into extra-skeletal species under inert, oxidizing, and / or steaming conditions at a temperature of 100°C to 800°C. The molar ratio of SiO2 to the framework metal oxide in the β-zeolite is greater than 10. Furthermore, the molar ratio of SiO2 to Al2O3 in the β-zeolite is greater than about 8, particularly greater than 10, such as greater than 10 to 2000 or 1000, for example 20 to 200, or 30 or 40 to 100 or 150. The SiO2 of the β-zeolite is mixed with cerium and / or cobalt metal oxides (in the form of CeO2). x or CoO x The molar ratio (in the form of) is greater than 10, such as greater than 10 to 2000 or 15 to 1000, for example 30 or 40 or 50 to 500 or 300.

[0032] To produce the heteroatom-doped zeolite of the present invention, heteroatoms are introduced into the synthetic gel before crystallization. Using the method of the present invention, heteroatoms can exist both within the framework sites and as exoskeletal species. According to DR UV-vis measurements, many exoskeletal species acting as impurities in the heteroatom-containing zeolite exhibit significant dispersion compared to the bulk zeolite. Therefore, such species can be used as promoters, adjacent to the acid sites of the zeolite framework, to enhance the performance of bifunctional reactions. This differs from prior art zeolite β and other zeolites in which heteroatoms are introduced into the framework sites post-synthesis. Verification of heteroatom incorporation into the zeolite framework T sites has been limited by available characterization techniques. While indirect incorporation has been reported, for example through catalytic test results, it remains unclear until now whether incorporation occurs through framework sites or as exoskeletal species.

[0033] For the hydroisomerization of bifunctional heptane, various heteroatoms are beneficial as promoters. Heteratoms in the framework or at ion exchange sites have demonstrated this promoting effect. For example, U.S. Publication No. 2015 / 0273450A1 describes the addition of zinc, titanium, and zirconium to framework sites to improve the activity and selectivity of the ZSM-48 catalyst. When the material contains titanium, the highest yield of isohexadecane was obtained and confirmed. Enhanced activity in hydroisomerization with the incorporation of the framework includes Mn, Fe, and Ga. Introducing different heteroatoms at ion exchange sites can be beneficial to both activity and selectivity. Examples include La, Fe, and Co, which can be found in the following literature: Liu et al., Rare Earth Metals Ion-exchanged β–zeolites as Supports of Platinum Catalysts for Hydroisomerization of n-heptane, Chin. J. Chem. Eng., 19, 278, 2011; Ushiki et al., Co-loading of Pt and Fe on*BEAZeolite for Enhanced Isomerization Selectivity in n-Heptane Conversion, Chem. Lett. 47, 1428-1430, 2018; and Izutsu et al., Synthesis and Characterization of Chromium-Added Pt / Beta Zeolites and its Catalytic Performance of n-Heptane Isomerization, Catal. Lett., 143, 486, 2013.

[0034] As described in the embodiments herein, the catalysts of the present invention exhibit selectivity and high activity for light straight-chain alkanes compared to conventional single-metal Pt / Al-β catalysts. The catalysts of the present invention exhibit selectivity for C5, C6, and C7 mixed hydrocarbon feedstocks in hydroisomerization reactions. Compared to mixed metal oxide catalysts Pt / Fe / WZrOx and Pt / Al-MOR catalysts, the catalysts of the present invention provide the same or higher conversion and selectivity while operating at higher temperatures.

[0035] As further taught in the embodiments, unconventional heteroatoms such as cerium (“Ce”) and cobalt (“Co”) are added to β-zeolite to synthesize heteroatom-doped zeolite Al-β-zeolite. Therefore, in one aspect, the present invention relates to a method for synthesizing heteroatom-doped β-zeolite having a trivalent cation (e.g., Al) as a framework metal and an extra-framework species composed of Ce and / or Co, the method comprising preparing Al-β-zeolite by conventional methods, but introducing heteroatoms (i.e., Ce and / or Co) into a reaction mixture (or synthetic gel) prior to crystallization. Therefore, the method includes the step of preparing a reaction mixture (or synthetic gel) having a composition suitable for preparing Al-β-zeolite, wherein the reaction mixture (or synthetic gel) further comprises at least one cerium and / or cobalt source. Suitable cerium and cobalt sources include their salts, especially their water-soluble salts, such as cerium and / or cobalt nitrates, sulfates, acetates, and halides such as chlorides and bromides. In one aspect, SiO2 in the reaction mixture is reacted with at least one cerium and / or cobalt source (denoted as CeO2). x or CoO x The molar ratio of the β-zeolite to the heteroatom-doped β-zeolite is greater than 10, such as from greater than 10 to 2000 or from 15 to 1000, for example from 30 or 40 or 50 to 500 or 300. The reaction mixture is then heated until crystallization occurs. The product crystallized from the hot reaction mixture can be conventionally separated, washed with water, and dried. The method may also additionally include the step of calcining the heteroatom-doped (Ce-doped and / or Co-doped) β-zeolite at a temperature of 100°C to 800°C under inert, oxidizing, and / or steaming conditions to convert at least a portion of the Ce and / or Co atoms into extra-skeletal species.

[0036] When applied to hydroisomerization reactions, these zeolites exhibit a conversion-selectivity tradeoff comparable to conventional single-metal Pt / Al-β zeolites. The absence of certain elements, such as tin (“Sn”), does not contribute to this enhancement, highlighting the importance of elemental selection. Despite operation at higher temperatures (Pt / CeAl-β 250 °C, Pt / Fe / WZrOx 170 °C), Pt / Ce,Al-β demonstrates C5, C6, and C7 selectivity in the hydroisomerization of mixed hydrocarbon feeds from Pt / Fe / WZrOx. This represents an improvement in the conversion-selectivity tradeoff compared to conventional Pt / Al-β prepared in a similar manner.

[0037] As described above, heteroatoms are introduced into the synthesis prior to zeolite crystallization and can be partially removed from the framework sites during calcination. This method is the opposite of that used in heteroatom-containing zeolites with heteroatoms in the framework sites. According to DR UV-vis measurements, extra-framework species acting as impurities in heteroatom-doped zeolites exhibit significant dispersion compared to zeolites containing bulk oxides and heteroatoms. These extra-framework species can be used as promoters, located immediately adjacent to the acid sites in the zeolite framework, to enhance the performance of bifunctional reactions and the catalysts used therein.

[0038] β-zeolite

[0039] As described in U.S. Patent No. 3,308,069 and U.S. Reissue Patent 28,341, β-zeolite (sometimes also called "zeolite β") is a crystalline aluminosilicate zeolite with an open three-dimensional framework of SiO4 and AlO4 tetrahedra cross-linked by shared oxygen atoms, thus the ratio of oxygen atoms to the total number of aluminum and silicon atoms is equal to two. The negative valence of the aluminum-containing tetrahedra is balanced by including cations such as alkali metal or alkaline earth metal ions within the crystal.

[0040] Zeolites possess a crystal structure with channels at the molecular scale. These interstitial spaces are initially occupied by hydrated water. After at least partial dehydration, these zeolites become effective adsorbents, thus retaining adsorbate molecules within these interstitial spaces. The interstitial size of the openings in the crystal lattice restricts the size and shape of the adsorbed molecules. Therefore, mixtures of various molecules can be separated based on molecular size, where some molecules are adsorbed by the zeolite while others may be excluded.

[0041] According to an embodiment of the present invention, β-zeolite may have the following calculated composition:

[0042] [XNa(1.0±0.lX)TEA]AlO2·YSiO2·WH2O

[0043] Depending on the dehydration conditions and the presence of metal cations, X is less than 1 or less than 0.75; TEA represents tetraethylammonium ions; Y is greater than 5 but less than 100; and W is at most about 4. The TEA component is calculated by the difference between the analytical value of the ratio of sodium to the final theoretical Al cations, which is 1.0 / 1.

[0044] β-zeolite is prepared by heating a mixture of oxides or a material whose chemical composition can be expressed as a mixture of oxides such as Na₂O, Al₂O₃, [(C₂H₅)₄N]₂O, SiO₂, and H₂O in an aqueous solution at a temperature of about 75°C to 200°C until crystallization occurs, using a reaction mixture containing tetraethylammonium hydroxide. The composition of the reaction mixture, expressed in molar ratios, falls within the following ranges: SiO₂ / AlO₂ from about 10 to about 200; Na₂O / tetraethylammonium hydroxide (TEAOH) from about 0.0 to 0.1; TEAOH / SiO₂ from about 0.1 to about 1.0; and H₂O / TEAOH from about 20 to about 75. The product crystallized from the heated reaction mixture is separated by centrifugation or filtration, washed with water, and dried. The material thus obtained can be calcined in air or an inert atmosphere at a temperature in the approximate range of about 400°F (204°C) to about 1700°F (927°C) or higher, provided that the temperature is insufficient to destroy crystallinity.

[0045] To produce β-zeolite, the method involves reacting amorphous silica solids or sols with soluble aluminates and an aqueous solution of tetraethylammonium hydroxide in an aqueous medium. The aluminate can be sodium aluminate or tetraethylammonium aluminate. Amorphous silica-alumina solids can be used as the source of both silica and alumina. The reaction mixture is initially stirred continuously or periodically to ensure homogeneity. After such mixing, stirring can be stopped because it is unnecessary to stir the reactants during zeolite formation and crystallization, but no harmful effects have been found from mixing during these later stages.

[0046] The crystallization process can be carried out at temperatures ranging from about 75°C to about 200°C. The pressure during crystallization is atmospheric pressure, or at least the vapor pressure of water in equilibrium with the reactant mixture. Heating continues until the desired crystalline zeolite product is formed. The zeolite crystals are then separated from the mother liquor and washed with distilled water or the like.

[0047] β-zeolite differs from other crystalline aluminosilicates in several ways. First, it possesses a novel structure, as defined by X-ray crystallography. Second, β-zeolite exhibits a novel combination of adsorption properties. Its adsorption capacities for cyclohexane, n-hexane, and H₂O are approximately the same or within the same order of magnitude. Furthermore, its H₂O adsorption capacity does not exceed that for cyclohexane. Additionally, the SiO₂ / AlO₂ ratio can be high and variable, ranging from 10 to 100, and can even reach up to 150.

[0048] β-zeolite catalysts can be prepared by calcining the original sodium form of β-zeolite and / or by replacing most of the sodium in the zeolite with other metal ions and / or ammonia ions. If calcination is performed before ion exchange, some or all of the resulting hydrogen ions can be replaced with metal ions during the ion exchange process.

[0049] β-zeolite can also be used as an adsorbent in various forms. For example, columns of powdered crystalline material can provide excellent results, as can granular forms obtained by pressing a mixture of β-zeolite with a suitable binder such as clay into granules.

[0050] Highly active conversion catalysts can be obtained by treating the β-zeolite of the present invention with a fluid medium containing sufficient amounts of hydrogen ions or ions capable of being converted into hydrogen ions to impart catalytic properties. The catalysts thus obtained exhibit a broad spectrum of catalytic activity; can be used at extremely low concentrations; and allow certain hydrocarbon conversion processes to proceed at feasible and controllable rates at temperatures much lower than previously employed.

[0051] The envisioned highly active catalyst is obtained by contacting the β-zeolite of the present invention with a fluid medium containing hydrogen ions or ions capable of being converted into hydrogen ions, washing the treated material to remove soluble anions, drying it, and then thermally activating the product by heating it at a temperature ranging from about 400℉ (204°C) to 1700℉ (927°C) or higher for a period of time between one hour and forty-eight hours. The resulting product is an activated aluminosilicate containing less than about 10% by weight of metal and having a strong acid nature that corresponds substantially to the hydrogen form of the β-zeolite precursor material. When subsequently used alone or in combination in a state with a particle size of less than about 40 micrometers, the resulting product, whether dispersed or otherwise tightly mixed, has been found to be active as a catalyst for hydrocarbon conversion.

[0052] Compositions produced by treating β-zeolite with a fluid medium containing hydrogen ions, ammonium ions, or a combination of ammonium ions and metal ions, or mixtures thereof, can be used as catalysts for a variety of hydrocarbon conversion processes, including isomerization / hydroisomerization, disproportionation, olefin hydration, olefin amination, oxidation, dehydrogenation, alcohol dehydration, desulfurization, hydrogenation, reforming, hydrocracking, polymerization, etc. These catalysts are stable at temperatures ranging from 70℉ (21°C) to 1000℉ (538°C), including processes involving periodic catalyst regeneration through the burnout of combustible deposits. Due to their high catalytic activity, these catalysts can be used to achieve various hydrocarbon conversion processes, such as alkylation, for example, at relatively low temperatures with small amounts of catalyst, thus providing minimal adverse side reactions and operating costs.

[0053] The catalyst containing the heteroatom-doped β-zeolite of the present invention can be used, either as is or as an intermediate, to prepare other modified contact materials containing low-activity or catalytically active materials, which serve as a support or matrix for aluminosilicates. The catalyst can be used in powder, granular, or molded form, wherein the molded form is spheres or agglomerates formed from ground particles with a particle size of 2 to 500 mesh. In the case of molded catalysts, such as by extrusion, the aluminosilicate can be extruded before drying, or dried or partially dried before extrusion. The catalyst product is then preferably pre-calcined in an inert atmosphere, or can be initially calcined when used in a conversion process. Typically, the composition is dried between 150℉ (66°C) and 600℉ (315°C), and then calcined in an inert atmosphere of air or steam or nitrogen, hydrogen, helium, flue gas, or other inert gases at a temperature ranging from 400℉ (204°C) to 1700℉ (927°C) for a period of one hour to forty-eight hours or longer. This heating step is called thermal activation of the catalyst.

[0054] The catalyst of the present invention can be prepared in any desired physical form, including small fragments of the size best suited for operation under the present specific conditions. Thus, the catalyst can be in the form of a ground powder or in the form of granules of 1 / 16" to 1 / 8" size, for example, obtained after granulation, casting, or extrusion according to well-known techniques.

[0055] The catalyst of the present invention can be used in hydroisomerization processes comprising catalysts having a low silica to alumina ratio. For example, the silica to alumina ratio in the zeolite can be less than about 200:1, such as less than about 110:1, or less than about 100:1, or less than about 90:1, or less than about 75:1. In various aspects, the silica to alumina ratio can be from 50:1 to 200:1, such as 20:1 to 160:1 or 30:1 to 100:1.

[0056] In one aspect, the catalyst of the present invention comprises a metal hydride component. The metal hydride component is typically a Group VIB and / or Group VIII metal. In one aspect, the metal hydride component may be Pt, Pd, or a mixture thereof. In an alternative, the metal hydride component may be a combination of a Group VIII non-noble metal and a Group VIB metal.

[0057] The metal hydrogenation component is added to the catalyst in any convenient manner. One technique for adding the metal hydrogenation component is through a pre-wetting process. For example, zeolite and binder are combined, and the combined zeolite and binder can be extruded into catalyst particles. These catalyst particles are then contacted with a solution containing a suitable metal precursor. Alternatively, the metal can be added to the catalyst via ion exchange, wherein the metal precursor is added to the zeolite (or zeolite and binder) mixture prior to extrusion.

[0058] The amount of metal in the catalyst may be at least 0.1 wt%, or at least about 0.15 wt%, or at least about 0.2 wt%, or at least about 0.25 wt%, or at least about 0.3 wt%, or at least about 0.5 wt%, based on the catalyst. The amount of metal in the catalyst may be about 20 wt% or less, or about 10 wt% or less, or about 5 wt% or less, or about 2.5 wt% or less, or about 1 wt% or less, based on the catalyst. When the metal is Pt, Pd, another Group VIII noble metal, or a combination thereof, the amount of the metal may be about 0.1 wt% to about 5 wt%, about 0.1 wt% to about 2 wt%, or about 0.25 wt% to about 1.8 wt%, or about 0.4 wt% to about 1.5 wt%. For aspects where the metal is a combination of Group VIII non-noble metals and Group VIB metals, the amount of the metal combination may be from 0.5 wt% to 20 wt%, or from 1 wt% to 15 wt%, or from 2.5 wt% to 10 wt%.

[0059] The catalyst of the present invention may also include a binder. In some embodiments, the dewaxing catalyst may be formulated using a low surface area binder, wherein a low surface area binder refers to a surface area of ​​100 m². 2 / g or less, or 80m 2 / g or less, or 70m 2 / g or less of binder. In catalysts formulated using binder, the amount of zeolite can be from about 30% by weight to 90% by weight of zeolite relative to the combined weight of binder and zeolite. The amount of zeolite is at least about 50% by weight of the combined weight of zeolite and binder, such as at least about 60% by weight or about 65% by weight to about 80% by weight.

[0060] According to various embodiments of the invention, zeolite can be combined with a binder in any convenient manner. For example, a combined catalyst can be manufactured by starting with powders of both zeolite and binder, combining the powders with added water and grinding to form a mixture, and then extruding the mixture to produce a combined catalyst of the desired size. Extrusion aids can also be used to modify the extrusion fluid properties of the zeolite and binder mixture. The amount of framework alumina in the catalyst can range from 0.1 wt% to 3.33 wt%, or 0.1 wt% to 2.7 wt%, or 0.2 wt% to 2 wt%, or 0.3 wt% to 1 wt%.

[0061] Hydroisomerization method

[0062] Hydroisomerization of straight-chain and single-branched alkanes (alkanes) can increase the octane number of gasoline fuel products. Alkanes are isomerized using bifunctional catalysts such as zeolites or mixed metal oxide catalysts, which promote alkane isomerization through dehydrogenation, protonation to form carbocations, and skeletal rearrangement of carbocations through mechanisms such as those involving cyclopropyl cations.

[0063] In conventional alkane hydroisomerization methods, the hydrocarbon feed is heated in the presence of hydrogen and a suitable bifunctional catalyst. For example, U.S. Patent Application Publication 2013 / 0324782 describes a conventional alkane isomerization method using a bifunctional catalyst. Furthermore, U.S. Patents 6,080,904 and 6,124,232 provide details of bifunctional catalysts as acidic metal oxide catalysts and alkane isomerization methods using such catalysts to isomerize C5 and C6 straight-chain (n-) alkanes. Other catalysts, including alumina chloride, zirconium oxide sulfate, and certain zeolites, can isomerize C5 and C6 straight-chain alkanes with high selectivity for cracking.

[0064] Conversely, C 7+ N-alkanes readily crack under isomerization reaction conditions, especially at higher reaction temperatures. Excessive cracking leads to a loss of the desired branched-chain alkane yield and a decrease in octane number. Unbound by any theory or mechanism, cracking is thought to occur via β-cleavage of a cationic intermediate. During β-cleavage, C5 and C6 n-alkanes result in the formation of an ethyl cation, a primary carbocation that is difficult to form. In contrast, during β-cleavage, C... 7+ Alkanes can form more stable and readily generated secondary or tertiary carbocations. Therefore, given their favorable thermodynamic properties for promoting cracking, it can sometimes be difficult to reduce C under isomerization reaction conditions. 7+ Cracking of alkanes.

[0065] U.S. shale oil production is increasing rapidly. Shale oil typically requires additional processing before it can be used in fuel blends. While branched hydrocarbons with high octane numbers are ideal blending components for producing premium gasoline, C7 and C8 straight-chain alkanes are the dominant components of this hydrocarbon resource and are easily cracked during conventional processing. Although the C... 8+ Catalytic reforming of components is feasible, but it is energy inefficient and results in a large portion of hydrocarbon resources remaining unconverted.

[0066] As mentioned above, the hydrogenation isomerization of n-alkanes increases the octane number, but C... 7+ Excessive cracking of n-alkanes presents problems in various aspects. To combat the cracking of C2O4... 7+ The thermodynamic advantages of n-alkanes, with their isomerization occurring at lower temperatures and lower feed mixture conversion rates, may be undesirable from a processing efficiency standpoint. Therefore, for hydrocarbon resources containing a large proportion of n-alkanes, such as naphtha, especially those with a large C20 content, isomerization may be less desirable. 7+ Hydrocarbon resources containing unbranched and monobranched alkanes may be difficult to improve in terms of octane number.

[0067] As described herein, the hydroisomerization method includes using a catalyst in a mixed feedstock that can selectively convert high-carbon-number light alkanes to achieve a maximum C7 conversion level determined by equilibrium, followed by a separation unit to remove partially converted C5 and C6, and further hydroisomerization of the unconverted light alkanes to obtain multi-branched products. In the method of this invention, the hydrocarbon feedstock for hydroisomerization processing may contain C5-C6. 30 n-Alkanes, such as C5-C7 n-alkanes or C 7+ n-chain alkanes and / or branched alkanes. The hydrocarbon feedstock also contains C2. 7+ n-Alkanes, such as C8-C 30 n-chain alkanes, and branched alkanes (e.g., C5 branched alkanes, C6 branched alkanes, or C... 7+ The hydrocarbon feedstock comprises, but is not limited to, monobranched alkanes, C5-type normal alkanes, C6-type normal alkanes, or any combination thereof. Therefore, the hydrocarbon feedstock comprises normal or monobranched C5-type alkanes, normal or monobranched C6-type alkanes, and normal or monobranched C7-type alkanes. Optionally, such hydrocarbon feedstocks also contain at least some normal or monobranched C8-type alkanes. Other hydrocarbon feedstocks that can be used with the catalyst of the present invention may comprise C... 10 -C 10 n-Alkanes or branched alkanes. Any of the above-mentioned hydrocarbon feedstocks may also contain one or more aromatic compounds.

[0068] Optionally, one or more cycloalkane compounds are combined with the hydrocarbon feedstock. Including one or more cycloalkane compounds as a co-feed can further reduce the incidence of cracking. About 10% by weight or more of the cycloalkane compound may be present in combination with the hydrocarbon feedstock. Suitable cycloalkane compounds include branched cycloalkane compounds such as methylcyclopentane (MCP), methylcyclohexane (MCH), or any combination thereof. Other suitable branched cycloalkane compounds, such as ethylcyclopentane, propylcyclopentane, 1,1-dimethylcyclopentane, 1,1-dimethylcyclohexane, ethylcyclohexane, propylcyclohexane, etc., are also suitable for use in the methods described herein, including bicyclic cycloalkane compounds. Generally, any cycloalkane compound that can form a tertiary carbocation under isomerization reaction conditions can be effectively used in the hydroisomerization process with the catalyst of the present invention.

[0069] In the hydroisomerization method, one or more catalysts are contacted with the hydrocarbon feedstock under one or more of the following isomerization reaction conditions: a temperature in the range of about 150°C to about 300°C or about 170°C to about 270°C; a molar ratio of hydrogen to hydrocarbon feedstock of about 1:1 to about 3:1; a pressure in the range of about 100 psig to about 350 psig; and a liquid hourly space velocity of about 0.5 h⁻¹. -1 approximately 6 hours -1 Within a certain range. For example, the partial pressure of hydrogen is in the range of about 50 kPa to about 2000 kPa. In a specific embodiment, the hydroisomerization reaction conditions include about 6 hours. -1 Or smaller, or about 5 hours -1 Or smaller, or about 4 hours -1 or smaller, and about 2 hours -1 approximately 5 hours -1 The liquid hourly space velocity (LHSV) is specified. The hydroisomerization reaction conditions allow the hydroisomerization reaction to proceed in the gas phase, supercritical phase, or liquid phase. These hydroisomerization reaction conditions provide approximately 95% or less, or approximately 90% or less, or approximately 85% or less, or approximately 80% or less, or approximately 75% or less, or approximately 70% or less conversion of C5-C7 n-alkanes. Using the catalyst of this invention, C... 7+ The conversion rate of n-alkanes is about 70% to about 90%. The cracking yield of n-heptane is about 10% by weight or less, and the ratio of n-heptane isomerization to cracking yield is about 10 or more, such as about 10 to about 25 or about 10 to about 20.

[0070] Pt / Fe / WZrOx catalyst

[0071] As taught in co-pending application U.S. Provisional Application 17 / 349986 (2021EM062-US), a mixed metal oxide catalyst, referred to as a Pt / Fe / WZrOx catalyst (or EMM-62), is at least partially crystalline and comprises tungsten, zirconium, and a variable oxidation state metal. The variable oxidation state metal comprises a metal selected from Fe, Mn, Co, Cu, Ce, Ni, and any combination thereof. The Pt / Fe / WZrOx catalyst has approximately 5 wt% to approximately 25 wt% tungsten, approximately 40 wt% to approximately 70 wt% zirconium, and approximately 0.01 wt% to approximately 5 wt% of the variable oxidation state metal, each based on the total mass of the mixed metal oxide. The total surface area of ​​the Pt / Fe / WZrOx catalyst, as measured according to ISO 9277, is approximately 50 m². 2 / g or greater, and having at least one of the following: ammonia absorption of about 0.05 mmol / g to about 0.3 mmol / g as measured by temperature-programmed adsorption / desorption, or trimethylpyridine absorption of about 100 μmol / g or greater as measured by gravimetric analysis.

[0072] To prepare the Pt / Fe / WZrOx catalyst, zirconium, tungsten, and a variable oxidation state metal are combined in a reaction mixture under alkaline conditions with a pH of about 7.5 or greater. The variable oxidation state metal comprises a metal selected from Fe, Mn, Co, Cu, Ce, Ni, and any combination thereof. Under these alkaline conditions, a slurry comprising a co-precipitated reaction product formed from zirconium, tungsten, and the variable oxidation state metal is obtained. The slurry is boiled to form an amorphous boil-off product from the co-precipitated reaction product. The amorphous boil-off product is calcined in air at a temperature of about 700°C to about 900°C to obtain a mixed metal oxide, which is at least partially crystalline and comprises about 5 wt% to about 25 wt% tungsten, about 40 wt% to about 70 wt% zirconium, and about 0.01 wt% to about 5 wt% of the variable oxidation state metal, each based on the total mass of the mixed metal oxide. The total surface area of ​​the mixed metal oxide, as measured according to ISO 9277, is about 50 m². 2 / g or greater, and having at least one of the following: ammonia absorption of about 0.05 mmol / g to about 0.3 mmol / g as measured by temperature-programmed adsorption / desorption, or trimethylpyridine absorption of about 100 μmol / g or greater as measured by gravimetric analysis.

[0073] Pt / Al-MOR catalyst

[0074] As described in published international patent applications WO2016 / 126431 and WO2018 / 160327, the mesopore surface area of ​​the Pt / Al-MOR catalyst is greater than 30 m². 2 / g and contains aggregates composed of primary grains, wherein the average primary crystal size, as measured by TEM, is less than 80 nm, the aspect ratio is less than 2, and the total surface area is greater than 500 m². 2 / g. In some embodiments, the Pt / Al-MOR catalyst (sometimes also called EMM-34) has a mesopore surface area to total surface area ratio greater than 0.05 and is synthesized from TEA or MTEA.

[0075] Pt / Al-MOR catalysts, also known as mesoporous mordenite zeolites, are zeolites synthesized using structure-directing agents TEA (tetraethylammonium cation) or MTEA (methyltriethylammonium cation). They have a mesoporous surface area greater than 30 m². 2 / g and contains aggregates consisting of primary grains having an average primary crystal size of less than 80 nm and an aspect ratio of less than 2, as measured by TEM.

[0076] The Pt / Al-MOR catalyst has a mesopore surface area greater than 30 m² as measured by BET. 2 / g, greater than 40m 2 / g, in some cases greater than 45m 2 / g. The Pt / Al-MOR catalyst comprises aggregates of primary grains, typically irregular aggregates, wherein the average primary crystal size, as measured by TEM, is less than 80 nm, less than 70 nm, less than 60 nm, for example, less than 50 nm. The average primary crystal size, as measured by TEM, can be in the range of greater than 20 nm, optionally greater than 30 nm to less than 80 nm.

[0077] Optionally, the average primary crystal size of the Pt / Al-MOR catalyst, as measured by X-ray diffraction, on each of the a, b, and c crystal vectors is less than 80 nm, less than 70 nm, and in some cases less than 60 nm. The average primary crystal size, as measured by X-ray diffraction, on each of the a, b, and c crystal vectors can optionally be in the range of greater than 20 nm, and optionally greater than 30 nm to less than 80 nm.

[0078] Pt / Al-MOR catalysts typically consist of a mixture of primary crystal aggregates and some unaggregated primary crystals. The majority of the Pt / Al-MOR catalyst, for example, greater than 80% or 90% by weight, will be present as primary crystal aggregates. These aggregates are usually irregular in form. For more information on aggregates, see, for example, Walter, D., Primary Particles-Agglomerates-Aggregates, in Nanomaterials, Deutsche Forschungsgemeinschaft (DFG), Wiley, 1-24, 2013.

[0079] Optionally, the Pt / Al-MOR catalyst comprises at least 50 wt%, at least 70 wt%, advantageously at least 80 wt%, or at least 90 wt% of irregular agglomerates, and optionally consists substantially of irregular agglomerates composed of primary crystal grains with primary crystal sizes less than 80 nm, less than 70 nm, or less than 60 nm, for example, less than 50 nm. The Pt / Al-MOR catalyst comprises less than 10 wt% of primary crystal grains, the size of which, as evaluated by TEM, is greater than 80 nm. The Pt / Al-MOR catalyst has irregular agglomerates composed of crystal grains, the crystal size of which, as measured by TEM, is less than 80 nm. As evaluated by TEM, the Pt / Al-MOR catalyst is substantially free of needle-like or plate-like crystals, for example, containing less than 10% by number of needle-like or plate-like crystals.

[0080] The primary grains of the Pt / Al-MOR catalyst have an aspect ratio of less than 3.0, more preferably less than 2.0, wherein the aspect ratio is defined as the longest dimension of the grain divided by the width of the grain, wherein the width of the grain is defined as the grain size at the midpoint of the longest dimension in a direction orthogonal to the longest dimension, as measured by TEM.

[0081] Aggregates of primary grains are typically irregular in form and can be referred to as “secondary” particles because they are formed from aggregates of grains, i.e., “primary” particles. The primary grains may have a narrow grain size distribution, such that at least 90% of the primary grains by number have an average primary crystal size in the range of 20 to 80 nm and / or 20 to 60 nm, as measured by TEM.

[0082] The total surface area of ​​the Pt / Al-MOR catalyst is greater than 500 m². 2 / g, greater than 550m 2 / g, in some cases greater than 600m 2 / g. The total surface area includes the surface area of ​​the internal pores (zeolite surface area) and the surface area of ​​the crystal exterior (external surface area). The total surface area is measured by BET. The ratio of the mesopore surface area to the total surface area of ​​Pt / Al-MOR is greater than 0.05. The mesopore volume of the Pt / Al-MOR catalyst is greater than 0.1 mL / g and / or greater than 0.12 mL / g, and in some cases greater than 0.15 mL / g.

[0083] Example

[0084] The features of the methods and compositions of the present invention are described in the following non-limiting examples.

[0085] Example 1: Synthesis of heteroatom-doped β-zeolite

[0086] Zeolite Synthesis

[0087] Aluminum nitrate (Al(NO3)3 9H2O) and heteroatom nitrates (such as Ce(NO3)3 6H2O or Co(NO3)2 6H2O) were dissolved in deionized water to form a clear solution. This clear solution was added to monodisperse colloidal silica (a 40 wt% suspension in H2O). Tetraethylammonium hydroxide (“TEAOH”) solution (35 wt%) was added and mixed to obtain a homogeneous gel. This homogeneous gel was placed inside a PTFE-lined steel autoclave and heated under hydrothermal conditions at 150°C and 20 rpm for approximately 5 to 6 days. The molar ratio was as follows: SiO2:TEAOH:Al(NO3)3:M(NO3)x:H2O equal to 1:0.4:0.05:y:16, where typically y is 0.005, 0.01, or 0, to obtain Al-β zeolite used as a control catalyst.

[0088] Zeolite was collected by centrifugation (typically 12,000 rpm for 5 minutes, repeated three times) and dried overnight in an oven at 120°C. It was then calcined at 550°C for six (6) hours with a three-hour heating cycle. Finally, it was ion-exchanged with Pt(NH3)4(NO3)2 at a ratio of 10 g solution / 1 g zeolite for 24 hours to obtain 0.6 wt% Pt in the final product. Zeolite was collected by centrifugation and calcined at 550°C for three (3) hours.

[0089] Characterization

[0090] The X-ray diffraction ("XRD") pattern of Ce-doped Al-β zeolite (also referred to herein as "Ce,Al-β") at Si / Ce = 100 is shown below. Figure 1 The line above is shown, and it is associated with Al-β zeolite (also referred to as "Al-β" in this article), i.e. Figure 1The lines below are compared. Under these crystallization conditions, a highly crystalline *BEA-type zeolite framework (also referred to herein as BEA, or β-zeolite, or β-structured zeolite) was obtained in the presence of cerium (“Ce”) in the synthetic gel. DR UV-vis results for Ce-doped zeolite before and after calcination are shown below. Figure 2 As shown in Figure 1. Ce,Al-β before calcination is shown in Figure 2. Ce,Al-β after calcination is shown in Figure 2. For ease of comparison, the absorption intensity of the Kubelka-Munk function of the reference CeO2 was reduced to 1 / 20 of the original value. Figure 2 Line 3.

[0091] DR UV-vis spectroscopy detects the state of heteroatoms through ligand-to-metal charge transfer bands, or “LMCT” bands. In the case of heteroatoms in a single-atom state, this corresponds to charge transfer from oxygen to the metal. When oligomers or bulk oxides are formed, this charge transfer corresponds to electron transfer from the HOMO to LUMO electronic bands. Therefore, the absorption peak corresponding to the energy of the absorbed phonons indicates the degree of separation (or oligomerization) of the heteroatom oxide. In many cases, this is a measure for qualitatively studying the state of heteroatoms. As shown in the figure, the state of Ce changed before and after the calcination step, and the separation was reduced by this treatment. This result indicates that oligomeric cerium oxide was formed at sites outside the framework in the calcined zeolite. Compared to the reference spectrum of bulk CeO2, the absorption edge shifted to a shorter wavelength, indicating that the oligomerization did not form a bulk structure.

[0092] These characterization results indicate that the obtained product is a complex of nanoclusters of β-zeolite and CeOx species, with the CeOx species likely located close to the framework due to their high dispersibility.

[0093] Example 2: C7 hydroisomerization reaction using graded zeolite powder

[0094] Calcined zeolite powder was classified through a 40 / 60 sieve. The reaction was carried out using a high-throughput fixed-bed reactor with the following activation procedure:

[0095] The temperature was increased to 250°C (60°C / h heating rate) with a N2 flow (100 standard cubic centimeters / min (“sccm”)) and held at 250°C for one hour. The temperature was then decreased to 220°C (60°C / h cooling rate), and the reactor flow was changed to H2 with a back pressure of 200 psig. The catalyst was reduced with H2 for 3 hours (100 sccm). The reactor temperature was then set to the specified reaction operating temperature. The H2:n-C7 molar ratio of the hydrocarbon feed stream was set to 2:1, with partial pressures of 137.1 psia and 70.4 psia for H2 and C7, respectively.

[0096] like Figure 3 As shown, Ce-doped and Co-doped zeolites exhibit better conversion-selectivity tradeoffs for isomerization products compared to their undoped counterparts. Figure 3 The square symbol depicts the conversion rate of Pt / Ce,Al-β (WHSV = 2h). -1 4h -1 6h -1 Similarly, triangles represent Pt / Al-β, and circles represent Pt / Co,Al-β, each with a WHSV of 2h. -1 4h -1 6h -1 250 °C. For example, a +5% increment in selectivity was confirmed at a conversion level of approximately 74%. It should be noted that the conversion-selectivity tradeoff for platinum-doped Al-β zeolite (or "Pt / Al-β") is far superior to the results seen in previous literature (such as Wang 1997).

[0097] Interestingly, the incorporation of Sn's skeleton leads to a selective loss of isomerization products, making cracking the primary reaction pathway. Figure 4 Previously, the introduction of zirconium (“Zr”) was shown to lead to a significant increase in reaction temperature to achieve comparable conversion levels. See, for example, US Publication No. 2015 / 0273450. Here, the maximum yield was also reduced, making this material inferior to other counterparts. Therefore, the proper selection of dopant elements is crucial for improving performance. Figure 4 As shown, squares represent the results using Pt / Ce,Al-β, circles represent the results using Pt / Co,Al-β, and rhombuses represent the results using Pt / Sn,Al-β, each with a WHSV of 2h. -1 4h -1 6h -1 250℃; the triangle represents the result using Pt / Al-β, WHSV = 4h -1 6h -1 , 230℃.

[0098] Figure 3 The isomerization selectivity (%) of heteroatom-doped zeolites compared with the conversion rate (%) of n-heptane is shown: (1) Pt / Al-β with Pt of 0.6 wt% and Si / Al of 20; (2) Pt / Ce,Al-β with Pt of 0.6 wt% and Si / Al of 20 and Si / Ce of 100; (3) Pt / Co,Al-β with Pt of 0.6 wt% and Si / Al of 20 and Si / Co of 200, respectively, at 250 °C, where WHSV is 2, 4, and 6. Figure 4The isomerization selectivity (%) of heteroatom-doped zeolites compared with the conversion of n-heptane (%) is shown: (1) Pt / Al-β with Pt of 0.6 wt% and Si / Al of 20; (2) Pt / Ce,Al-β with Pt of 0.6 wt% and Si / Al of 20, and Si / Ce of 100; (3) Pt / Co,Al-β with Pt of 0.6 wt% and Si / Al of 20, and Si / Co of 200; (4) Pt / Sn,Al-β with Pt of 0.6 wt% and Si / Al of 20, and Si / Sn of 100 (prepared using SnCl2 5H2O), each at 230 °C, with WHSVs of 2, 4, and 6, respectively.

[0099] This example demonstrates that heteroatom-doped zeolites, as advanced bifunctional catalysts, are beneficial for enhancing the conversion-selectivity tradeoff in hydroisomerization reactions.

[0100] Example 3: Hydroisomerization run using a mixture of C5, C6, and C7 hydrocarbons as a light alkane model

[0101] Calcined zeolite powder was classified through a 40 / 60 sieve. A high-throughput fixed-bed reactor unit was used, and the reaction was carried out using the following activation procedure: the temperature was increased to 300°C (60°C / hr) at a rate of 100 sccm under a N2 flow and held at 300°C for 1 hour. The temperature was then reduced to 220°C (60°C / hr), the reactor flow was changed to H2, and the back pressure was 350 psig. The zeolite was reduced with H2 for 24 hours (100 sccm). The reactor temperature was then set to the specified reaction operating temperature. The hydrocarbon feed flow was as follows: n-C5:n-C6:n-C7 = 1:1:1 (by weight); H2:n-alkane molar ratio = 2:1 (by moles). The total reactor pressure was set to 180 psia.

[0102] Figure 5A The study shows the increase in octane number (“RON”) at 250 °C relative to the formation of light gases (C1 to C4), wherein the reaction is carried out at a weight hourly space velocity (“WHSV”) equal to 3 / h and 6 / h. Figure 5A In the diagram, squares represent Pt / Ce,Al-β, rhombuses represent Pt / Al-β, hexagonal stars represent Pt / Al-MOR, and circles represent Pt / Fe / WZrOx, each with a WHSV of 3h. -1 6h -1 . Figure 5B The conversion rates of n-heptane (wt%) versus C1 to C4 (wt%) are shown. Figure 5B In the diagram, squares represent Pt / Ce,Al-β, rhombuses represent Pt / Al-β, hexagonal stars represent Pt / Al-MOR, and circles represent Pt / Fe / WZrOx, each with a WHSV of 3h. -1 6h-1 .

[0103] Such as these Figure 5A and Figure 5B As shown, under constrained cracking conditions, Al-β zeolites with selective isomerization of the feed to increase RON and Ce doping exhibit outstanding performance. For example, Pt / Ce,Al-β formed only about 1% by weight of light gas cracking products while providing an RON increase of +18, which is comparable to or slightly better than the mixed metal oxide catalyst Pt / Fe / WZrOx used for this type of reaction. Note that the reaction temperatures of Pt / Fe / WZrOx (EMM-62) are 250°C and 170°C, while the Al-β zeolite samples prepared by the method of this invention operate under more severe conditions that favor cracking. Since mixed metal oxide-based catalysts can operate at lower temperatures, they have a performance advantage for this purpose. However, the present examples show that Al-β zeolites have performance comparable to their modified mixed metal oxide counterparts.

[0104] The improvement in gradient / total light gas formation based on RON is clearly compared to that of the original Pt / Al-β zeolite. The results support Ce as a selectivity promoter. Pt / Al,MOR is an in-use zeolite for the isomerization of light alkanes and is used as a model reference for comparison. PCT Publication WO2018 / 160327 describes this zeolite in paragraphs

[0053] ,

[0055] ,

[0058] ,

[0059] to

[0064] , which are incorporated herein by reference. Platinum Al-MOR (Pt / Al-MOR) exhibits higher cracking selectivity compared to Pt / Ce,Al-β zeolite, likely due to the zeolite's stronger acidity. These comparative results reinforce the practical advantage of Pt / Ce,Al-β zeolite over other zeolite-based hydroisomerization catalysts.

[0105] Furthermore, for the C7 conversion level in the feed mixture, under the same current conditions, Pt / Ce,Al-β zeolite significantly suppressed the formation of light gases compared to other catalysts. Figure 5B Compared to Pt / Al-β zeolite, the effect of Ce addition appears to be enhanced in the case of mixed alkane feeds. See also Figure 4 The result of using pure n-C7 feedstock is another significant advantage overall in improving the performance of hydroisomerization methods. Most conventional zeolite-based alkane isomerization units selectively convert C5 and C6, but C7 conversion is limited by the concentration levels in the hydrocarbon feedstock. The method of this invention is advantageous because the current isomerization capacity can be used for overall conversion without upstream purification processes, thereby reducing the cost of installing new reactors.

[0106] like Figure 6As shown, squares represent Pt / Ce,Al-β, rhombuses represent Pt / Al-β, hexagonal stars represent Pt / Al-MOR, and circles represent Pt / Fe / WZrOx, each with an LHSV of 3h. -1 6h -1 The relative conversions of C7 to C6 for Pt / Ce,Al-β, Pt / Al-β, and Pt / Fe / WZrOx are provided. Pt / Ce,Al-β zeolite can be distinguished from other catalysts because the conversion of C7 is more preferential than C6 when using Pt / Ce,Al-β zeolite. A similar trend is further shown by comparison with C5 (results not shown). These results illustrate the differences in the properties of the active sites, thus demonstrating the effect of heteroatom doping on zeolite.

[0107] Preferential C7 conversion is valuable in the following design approach: first, light alkane feed (C5-C7) is converted to achieve the highest C7 conversion level (determined by equilibrium), then partially converted C5 and C6 are removed by a separation unit. These partially converted C5 and C6 can be further processed using an existing light alkane hydroisomerization unit. Most conventional alkane isomerization units selectively convert C5 and C6, which limits the C7 concentration level in the hydrocarbon feedstock. However, as mentioned above, existing isomerization capacity can be used for overall conversion, thereby reducing the cost of installing new reactors.

[0108] Example 4: C7 hydroisomerization of zeolite extrudates using alumina binder

[0109] The reaction was carried out using a high-throughput fixed-bed reactor with a 70 / 30 zeolite / alumina extrudate, demonstrating that the extrudate is also active in the reaction.

[0110] The reaction conditions were as follows: the supported catalyst was pretreated by heating the reactor from 100°C to 400°C for 6 hours under an H2 flow of 200 cc / h. Two 100 cc ISCO pumps alternately introduced chemical-grade n-heptane feed to ensure uninterrupted flow. The feed was pumped to the reactor through a heated line, and the hydrogen flow rate was set using a Brooks mass flow controller. The pressure was maintained at 350 psig. The feed was then pumped through a catalyst bed maintained at a reaction temperature of 230°C at different LHSVs, a 2:1 hydrogen:hydrocarbon molar ratio, and a pressure of 350 psig. The liquid product leaving the reactor flowed through the heated line and was analyzed by a gas chromatograph with an FID detector.

[0111] Compared to the results of Example 2, the Co loading on the Co,Al-β zeolite increased from Si / Co = 200 to Si / Co = 100. These new zeolites resulted in conversion trade-off curves similar to those of the Ce counterpart. Figure 7In the diagram, the square symbol represents the conversion rate of Pt / Ce,Al-β (LHSV = 0.75 h⁻¹). -1 1h -1 1.5h -1 The circle represents Pt / Co,Al-β (LHSV = 0.75h). -1 1h -1 1.5h -1 This result indicates that heteroatom loading also plays a crucial role in catalytic performance as a promoter, and that the extruded zeolite still retains activity for the reaction.

[0112] Based on the above description, many changes, modifications and variations will be apparent to those skilled in the art without departing from the spirit or scope of this disclosure, and when lower and upper limits of numerical values ​​are listed herein, a range from any lower limit to any upper limit is contemplated.

[0113] Alternatively or concurrently, the present invention relates to:

[0114] Implementation Method 1: A method for hydroisomerization of a hydrocarbon feedstock, the method comprising contacting the hydrocarbon feedstock with hydrogen and a catalyst to produce a hydrocarbon product having an increased number of branched hydrocarbons relative to the hydrocarbon feedstock, wherein the catalyst comprises heteroatom-doped β-zeolite having a trivalent cation as a framework metal oxide, an extra-framework species consisting of cerium and / or cobalt, and 0.01 wt% to 1.5 wt% of a Group VIII or Group VIB metal, or a combination thereof.

[0115] Implementation Method 2: According to the method described in Implementation Method 1, the molar ratio of SiO2 contained in the heteroatom-doped β-zeolite to the framework / external metal oxide is greater than 10.

[0116] Implementation Method 3: According to the method of Implementation Method 1 or 2, the molar ratio of SiO2 to Al2O3 contained in the heteroatom-doped β zeolite is greater than 8, preferably greater than 10.

[0117] Implementation Method 4: The method according to any of the foregoing embodiments, wherein the heteroatom-doped β-zeolite comprises SiO2 and cerium and / or cobalt metal oxides (represented as CeO2). x and CoO x The molar ratio of ) is greater than 10.

[0118] Embodiment 5: The method according to any of the foregoing embodiments, wherein the catalyst further comprises a metal oxide binder.

[0119] Implementation Method 6: The method according to any of the foregoing embodiments, wherein the Group VIII or Group VIB metal is Pt, and in particular, wherein the catalyst contains 0.1% to 1.5% by weight of Pt.

[0120] Implementation Method 7: The method according to any of the foregoing embodiments, wherein the hydrocarbon feedstock is contacted with the catalyst under one or more isomerization conditions.

[0121] Implementation Method 8: The method according to Implementation Method 7, wherein the one or more isomerization conditions include a temperature of 100°C to 450°C, a pressure of 0 psig to 1000 psig, and 0.1 hr -1 up to 10 hours -1 WHSV, and / or a hydrogen / hydrocarbon molar ratio of about 0.1 to about 100.

[0122] Implementation 9: The method according to any of the foregoing embodiments, wherein the heteroatom-doped β-zeolite is selective for the conversion of n-heptane.

[0123] Implementation Method 10: The method according to any of the foregoing embodiments, wherein the hydrocarbon feedstock comprises n-pentane, n-hexane and / or n-heptane.

[0124] Embodiment 11: The method according to Embodiment 10, wherein the hydrocarbon feedstock further comprises cycloalkanes and / or one or more aromatic compounds.

[0125] Implementation Method 12: The method according to any of the foregoing embodiments, wherein the heteroatom-doped β-zeolite selectively converts light alkanes in the hydrocarbon feedstock into C5, C6 and C7.

[0126] Implementation method 13: The method according to implementation method 12, wherein C5 and C6 are separated from C7.

[0127] Embodiment 14: A method for synthesizing heteroatom-doped β-zeolite containing cerium or cobalt as an extra-skeletal species, the method comprising crystallizing a reaction mixture suitable for synthesizing β-zeolite, particularly aluminum-containing β-zeolite (Al-β-zeolite), wherein at least one of cerium and cobalt is added to the reaction mixture prior to crystallization, preferably in the form of cerium salts and / or cobalt salts, more preferably in the form of cerium and / or cobalt nitrates, sulfates, acetates and / or halides.

[0128] Embodiment 15: The method according to Embodiment 14, wherein the reaction mixture comprises water, SiO2 and a framework metal oxide, wherein the reaction mixture comprises:

[0129] The molar ratio of the structure-directing agent cation Q to SiO2 in the reaction mixture is 0 to 4;

[0130] The molar ratio of SiO2 to framework metal oxide in the reaction mixture is greater than 10.

[0131] The molar ratio of water to SiO2 in the reaction mixture is greater than 0;

[0132] The molar ratio of alkali metal M to SiO2 in the reaction mixture is 0 to 1; and

[0133] The molar ratio of SiO2 to Al source in the reaction mixture is greater than 5.

[0134] Embodiment 16: The method according to Embodiment 14 or 15, wherein the reaction mixture comprises SiO2 and the at least one cerium and / or cobalt source (denoted as CeO2). x or CoO x The molar ratio of ) is greater than 10.

[0135] Embodiment 17: The method according to any one of Embodiments 14 to 16, wherein the reaction mixture further comprises a structure directing agent and / or a mineralizing agent, preferably wherein the reaction mixture comprises tetraethylammonium (TEA) ions as a structure directing agent.

[0136] Embodiment 18: The method according to any one of Embodiments 14 to 17 further includes the step of calcining the heteroatom-doped β-zeolite under inert, oxidizing and / or steaming conditions at a temperature of about 100°C to about 800°C.

[0137] Embodiment 19: The method according to any one of Embodiments 14 to 18, wherein the chemical composition of the reaction mixture (in the absence of a cerium and / or cobalt source) is expressed as a mixture of Na2O, Al2O3, [(C2H5)N]2O(TEAOH), SiO2 and H2O; preferably, wherein the composition of the reaction mixture, expressed in molar ratios, has about 10 to about 200 SiO2 / AlO2, about 0.0 to 0.1 Na2O / TEAOH, about 0.1 to 1.0 TEAOH / SiO2 and about 20 to about 75 H2O / TEAOH.

[0138] Embodiment 20: The method according to any one of Embodiments 14 to 19, wherein the reaction mixture is heated at a temperature of about 75°C to about 200°C until crystallization occurs.

[0139] Embodiment 21: A composition comprising β-zeolite having cerium and / or cobalt extra-skeletal species and about 0.01 wt% to about 1.5 wt% Pt.

[0140] Embodiment 22: The composition according to Embodiment 21, wherein the β-zeolite contains a SiO2 to framework metal oxide molar ratio greater than 10.

[0141] Embodiment 23: The composition according to Embodiment 21 or 22, wherein the β zeolite contains a molar ratio of SiO2 to Al2O3 greater than 8.

[0142] Embodiment 24: The composition according to any one of Embodiments 21 to 23, wherein the β-zeolite comprises SiO2 and cerium and / or cobalt metal oxides (denoted as CeO2). x and CoO x The molar ratio of ) is greater than 10.

Claims

1. A method for hydroisomerization of a hydrocarbon feedstock, the method comprising contacting the hydrocarbon feedstock with hydrogen and a catalyst to produce a hydrocarbon product having an increased number of branched hydrocarbons relative to the hydrocarbon feedstock, wherein the catalyst comprises heteroatom-doped β-zeolite having a trivalent cation as a framework metal oxide, an extra-framework species consisting of oligomeric cerium oxide, and 0.01% to 1.5% by weight of a Group VIII or Group VIB metal.

2. The method according to claim 1, wherein the molar ratio of SiO2 contained in the heteroatom-doped β-zeolite to the framework / extra-framework metal oxide is greater than 10.

3. The method according to claim 1 or 2, wherein the heteroatom-doped β-zeolite contains a SiO2 to Al2O3 molar ratio greater than 8.

4. The method according to claim 1 or 2, wherein the heteroatom-doped β-zeolite comprises a SiO2 to cerium metal oxide molar ratio greater than 10, wherein the cerium metal oxide is represented as CeO2. x .

5. The method according to claim 1 or 2, wherein the catalyst further comprises a metal oxide binder.

6. The method according to claim 1 or 2, wherein the group VIII or group VIB metal is Pt.

7. The method of claim 6, wherein the catalyst comprises 0.1% to 1.5% by weight Pt.

8. The method according to claim 1 or 2, wherein the hydrocarbon feedstock is contacted with the catalyst under one or more isomerization conditions.

9. The method of claim 8, wherein the one or more isomerization conditions comprise a temperature of 100°C to 450°C, a pressure of 0 psig to 1000 psig, and 0.1 hr. -1 Up to 10 hr -1 WHSV, and / or a hydrogen / hydrocarbon molar ratio of 0.1 to 100.

10. The method according to claim 1 or 2, wherein the heteroatom-doped β-zeolite is selective for the conversion of n-heptane.

11. The method according to claim 1 or 2, wherein the hydrocarbon feedstock comprises n-pentane, n-hexane and / or n-heptane.

12. The method according to claim 11, wherein the hydrocarbon feedstock further comprises cycloalkanes and / or one or more aromatic compounds.

13. The method according to claim 1 or 2, wherein the heteroatom-doped β-zeolite selectively converts light alkanes in the hydrocarbon feedstock into C5, C6 and C7.

14. The method of claim 13, wherein C5 and C6 are separated from C7.

15. A method for synthesizing heteroatom-doped β-zeolite comprising oligomeric cerium oxide as an extra-skeletal species, the method comprising crystallizing a reaction mixture suitable for synthesizing β-zeolite, wherein cerium is added to the reaction mixture prior to crystallization; and calcining after crystallization.

16. The method of claim 15, wherein the β-zeolite is an aluminum-containing β-zeolite.

17. The method according to claim 15 or 16, wherein cerium is present in the form of a cerium salt.

18. The method according to claim 15 or 16, wherein cerium is present in the form of cerium nitrates, halides, acetates and sulfates.

19. The method of claim 15 or 16, wherein the reaction mixture comprises water, SiO2, and a framework metal oxide, wherein the reaction mixture comprises: The molar ratio of the structure-directing agent cation Q to SiO2 in the reaction mixture is 0 to 4; The molar ratio of SiO2 to framework metal oxide in the reaction mixture is greater than 10. The molar ratio of water to SiO2 in the reaction mixture is greater than 0; The molar ratio of alkali metal M to SiO2 in the reaction mixture is 0 to 1; and The molar ratio of SiO2 to Al source in the reaction mixture is greater than 5.

20. The method according to claim 15 or 16, wherein the reaction mixture further comprises a structure-directing agent and / or a mineralizing agent.

21. The method according to claim 15 or 16, wherein the reaction mixture comprises tetraethylammonium ions as a structure directing agent.

22. The method according to claim 15 or 16, further comprising the step of calcining the heteroatom-doped β-zeolite under inert, oxidizing and / or steaming conditions at a temperature of 100°C to 800°C.

23. A composition comprising β-zeolite having an oligomeric cerium oxide skeletal extraspecies and 0.01 wt% to 1.5 wt% Pt.

24. The composition of claim 23, wherein the β-zeolite comprises a SiO2 to cerium metal oxide in a molar ratio greater than 10, wherein the cerium metal oxide is represented as CeO2. x .

25. The composition according to claim 23 or 24, wherein the β-zeolite comprises a SiO2 to Al2O3 molar ratio greater than 8.

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