Titanated catalyst, method for preparing the same, and epoxidation method

Abstract

A method for preparing a titanated silica catalyst and the titanated silica catalyst are presented. The titanated silica catalyst may comprise a silica support, which may comprise spherical beads. The spherical silica beads may have an average diameter of about 0.1 mm to about 5 mm. A method for olefin epoxidation may include contacting an olefin with the titanated silica catalyst in the presence of an oxidant.

Description

[Technical Field]

[0001] Prior Related Applications This application claims the benefit of priority under the Patent Cooperation Treaty to U.S. Provisional Application No. 62 / 930,268, filed November 4, 2019, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Titanated silica systems are catalysts for propylene epoxidation processes that rely on hydroperoxides such as t-butyl hydroperoxide (TBHP), 1-ethylbutyl hydroperoxide (EBHP), or cumene hydroperoxide (CHP). These processes may involve treating a silica support with titanium chloride or one or more titanium alkoxides. However, titanium alkoxides and titanium halides can be moisture sensitive, pyrophoric, or both. Titanium chloride, while relatively inexpensive to purchase, can be expensive to handle because it is moisture sensitive, corrosive, and potentially toxic.

[0003] U.S. Patent Application Publication No. 2015 / 01822959 (incorporated herein by reference) discloses a process for preparing a titanium catalyst system for epoxidation reactions, the process comprising: (i) impregnating a silica support with a solution of a titanium compound in an inorganic solvent system; (ii) drying the support; (iii) calcining (i.e., "calcining") the dried product; and (iv) silylating the calcined (i.e., "calcined") product.

[0004] There remains a need for improved processes for preparing the aforementioned catalysts (including large-volume commercial catalysts) that are efficient, safer, cheaper, more environmentally friendly, or a combination thereof.

[0005] Many fixed-bed epoxidation catalysts contain a titanated silica support. The support may have a weight average particle size of 0.2 mm to 3 mm and contain particles of irregular shape. Examples of supports are disclosed in WO2017 / 080962 (incorporated herein by reference). The support in WO2017 / 080962 is 330 mm. 2 / g~450m 2 / g of surface area. However, these supports can suffer from one or more drawbacks associated with their use in fixed bed reactors, such as high pressure drop.

[0006] There remains a need for catalyst supports, including titanated silica supports, that overcome one or more of these drawbacks and / or perform better in fixed-bed reactors. Prior art catalysts lack sufficient crush strength. The present disclosure provides a solution to this problem by using spherical catalyst supports. Summary of the Invention

[0007] Provided herein are methods for preparing a titanium dioxide catalyst that are safe, relatively inexpensive, and / or environmentally friendly. The titanium dioxide catalyst can exhibit improved catalytic performance in processes such as epoxidation, and the degree of improvement is surprising. Also provided herein are titanium dioxide catalysts and methods for preparing the titanium dioxide catalyst that exhibit improved results in fixed-bed reactors. For example, the titanium dioxide catalyst can exhibit a surprising reduction in pressure drop compared to other catalyst systems.

[0008] In one aspect, a method for preparing a titanated silica catalyst is provided, the method including providing a silica support comprising a plurality of spherical silica beads; contacting the silica support with a titanium compound to form a titanated silica support; calcining the titanated silica support to form a calcined titanium-treated silica support; contacting the calcined titanium-treated silica support with water, steam, or an alcohol to form a water or alcohol adduct of the calcined titanium-treated support; and silylating the water or alcohol adduct of the calcined titanium-treated silica support to form the titanated silica catalyst.

[0009] In some embodiments, the method includes providing a silica support comprising a plurality of spherical silica beads having an average diameter in the range of about 0.1 mm to about 5 mm; and contacting the silica support with TiCl vapor to form a titanated silica support. The method may also include calcining the titanated silica support to form a calcined titanated silica support; contacting the calcined titanated silica support with water vapor; and silylating the calcined titanated silica support to form a titanated silica catalyst. The plurality of spherical silica beads may also be about 400 mm. 2 / g~about 600m 2 The surface properties may be measured by nitrogen adsorption isotherms collected at 77 K in the region P / P<0.3 (BET surface area) and P / P>0.95 (pore volume).

[0010] In some embodiments, the method includes providing a liquid comprising (i) a water-soluble organic compound and (ii) titanium(IV) bis(ammonium lactato) dihydroxide; and contacting a silica support with the liquid to deposit at least a portion of the titanium(IV) bis(ammonium lactato) dihydroxide on the silica support to form a titanium-treated silica support. The method also includes calcining the titanium-treated silica support, and / or This may include silylating the titanium treated silica support.

[0011] In another aspect, a method for olefin epoxidation is provided. In some embodiments, the method includes providing a titanated silica catalyst described herein or prepared by a method described herein; and contacting an olefin with the titanated silica catalyst in the presence of an oxidant and under conditions effective to epoxidize the olefin to form an epoxidized olefin.

[0012] In yet another aspect, a titanated catalyst is provided. In some embodiments, the titanated catalyst comprises a titanated catalyst system made by any of the methods described herein.

[0013] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the aspects described herein. The advantages described herein will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive. DETAILED DESCRIPTION OF THE INVENTION

[0014] Provided herein are titanated silica catalysts and methods for preparing titanated silica catalysts. The titanated catalysts provided herein may comprise a titanated silica support. The titanated silica support may have (i) an average diameter of about 0.1 mm to about 5 mm, (ii) an average diameter of about 400 mm, and (iii) a mean diameter of about 400 mm. 2 / g~about 600m 2 / g, and (iii) a plurality of spherical silica beads having a pore volume of from about 1 cc / g to about 2.5 cc / g. Method for preparing titanated silica catalyst

[0015] Methods for preparing titanated silica catalysts are provided. In some embodiments, the methods provided herein include providing a liquid or vapor containing titanium tetrachloride; and contacting a silica support with the liquid or vapor to deposit at least a portion of the titanium tetrachloride on the silica support, forming a titanium-treated silica support. A material is "on the silica support" when it is deposited on and / or within any portion of the silica support, such as on the surface, pores, interior regions (e.g., void spaces), etc.

[0016] In some embodiments, a solvent or diluent may be used, and examples of the solvent or diluent may include paraffinic or aromatic hydrocarbons.

[0017] Contacting the silica support with a liquid or vapor can be accomplished in any manner, including any technique. In some embodiments, contacting the silica support with a liquid or vapor includes impregnating the silica support with a liquid. The silica support is "impregnated" with a liquid when at least a portion of the liquid contacts a non-surface portion of the silica support. For example, impregnating the silica support with a liquid or vapor can result in at least a portion of the liquid being present in one or more interior spaces of the silica support.

[0018] In some embodiments, impregnating the silica support comprises subjecting the silica support to an incipient wetness impregnation process. In some such embodiments, a vacuum-assisted incipient wetness impregnation process may be used. The vacuum-assisted incipient wetness impregnation process may rely, at least in part, on capillary action to impregnate the silica support with a liquid. In some embodiments, the methods provided herein comprise providing a silica support comprising a plurality of spherical silica beads having an average diameter of about 0.1 mm to about 5 mm; and contacting the silica support with TiCl vapor to form a titanized silica support. In some embodiments, the plurality of spherical silica beads has an average diameter of about 0.75 mm to about 2.5 mm. In some embodiments, the plurality of spherical silica beads has an average diameter of about 1.0 mm to about 3.5 mm. In some embodiments, the plurality of spherical silica beads has an average diameter of about 1.5 mm to about 4.25 mm. In some embodiments, the plurality of spherical silica beads has an average diameter of about 1.75 mm to about 2.5 mm. In some embodiments, the plurality of spherical silica beads has an average diameter of about 0.75 mm to about 1.5 mm. The method may also include calcining the titanium-treated silica support to form a calcined titanium-treated silica support; contacting the calcined titanium-treated silica support with water vapor; and silylating the calcined titanium-treated silica support to form a titanated silica catalyst.

[0019] In some embodiments, the methods provided herein include calcining the titanium-treated silica support; and silylating the titanium-treated silica support to form a titanated silica catalyst.

[0020] In some embodiments, calcining the titanium-treated silica support comprises subjecting the titanium-treated silica support to an elevated temperature of about 100°C to about 1,000°C, about 300°C to about 800°C, or about 600°C to about 800°C. In some embodiments, calcining the titanium-treated silica support comprises heating the titanium-treated silica support in air to a temperature of about 500°C to about 750°C for about 1 hour to about 3 hours. In some embodiments, a temperature gradient is used. In some embodiments, the titanium-treated silica support is heated to about 100°C for about 15 minutes, then to about 250°C for about 15 minutes, and then to about 700°C for about 2 hours. In some embodiments, calcination is carried out under an inert atmosphere, such as nitrogen or a noble gas. In some embodiments, at least a first portion of the calcination is carried out under an inert gas, and then at least a second portion of the calcination is carried out in air. In some embodiments, calcination is carried out in an atmosphere containing oxygen. In some embodiments, calcination is carried out in the absence of oxygen.

[0021] After calcining the titanium-treated silica support, the calcined titanium-treated silica support may be washed or steamed.

[0022] In some embodiments, the titanium-treated silica support is washed with a solvent. In some embodiments, the solvent is a hydroxyl-containing liquid. In some embodiments, the hydroxyl-containing liquid includes an alcohol, water, or a combination thereof. The alcohol includes a C1-C hydroxyl group substituted with at least one hydroxyl moiety. 18 Hydrocarbyl may be included. In some embodiments, the titanium treated silica support is washed with a hydroxyl group-containing liquid at ambient temperature.

[0023] The washed titanium-treated silica support may be dried. In some embodiments, drying comprises subjecting the washed titanium-treated silica support to an elevated temperature. In some embodiments, the temperature is greater than 50°C. In some embodiments, the temperature is from about 50°C to about 200°C. In some embodiments, the temperature is from about 100°C to about 150°C. In some embodiments, the washed titanium-treated silica support is dried under a stream of inert gas. In some embodiments, the washed titanium-treated silica support is dried for from about 0.1 hours to about 2 hours. In some embodiments, the washed titanium-treated silica support is dried for from about 1 hour to about 4 hours. In some embodiments, the time is about 2 hours.

[0024] In some embodiments, silylating the titanium-treated silica support comprises contacting the titanium-treated silica support with a silylating agent. Any silylating agent may be used. In some embodiments, the silylating agent is an organosilane, an organosilylamine, an organosilazane, or a combination thereof. Examples of silylating agents are disclosed in U.S. Pat. No. 10,017,484, which is incorporated herein by reference.

[0025] In some embodiments, the silylating agent has the formula: R3SiNHSiR'3 where each R and R' is independently selected from C1 to C6 hydrocarbyl. In some embodiments, the silylating agent comprises hexamethyldisilazane. Silica Support

[0026] Any known silica support may be used in the methods provided herein. Non-limiting examples of silica supports include those disclosed in U.S. Patent No. 10,017,484, which is incorporated herein by reference.

[0027] In some embodiments, the silica support comprises an inorganic siliceous solid, such as silicon oxide. In some embodiments, the siliceous solid is amorphous silicon oxide. In some embodiments, the silica support is porous. A silica support is porous when it contains one or more pores and / or interstices within its structure.

[0028] In some embodiments, the silica support comprises a plurality of spherical silica beads. A bead is "spherical" if: [1] it is spherical; [2] its smallest diameter is 95% or more of its largest diameter (e.g., a smallest diameter of at least 1.9 mm and a largest diameter of 2 mm); and / or [3] it satisfies elements [1] and / or [2], provided it is free of defects such as surface imperfections (e.g., deep grooves, depressions, etc.). Non-limiting examples of spherical silica beads include AlphaCat® 4000 silica beads available from PQ Corporation (Malvern, Pennsylvania, USA).

[0029] In some embodiments, the silica support of the catalyst comprises silicon oxide. In some embodiments, the silica support comprises silicon oxide and titanium oxide. In some embodiments, the silica support comprises at least 90 wt. % silicon oxide, based on the weight of the silica support. In some embodiments, the silica support comprises at least 95 wt. % silicon oxide, based on the weight of the silica support. The percentage of silicon oxide and one or more other oxides in the silica support can be measured using XRF (X-ray fluorescence spectroscopy). In some embodiments, the one or more other oxides, e.g., titanium oxide, comprise less than about 10 wt. % of the silica support, based on the weight of the silica support. In some embodiments, the one or more other oxides comprise from about 0.01 wt. % to about 9.9 wt. % of the silica support, based on the weight of the silica support.

[0030] In some embodiments, the silicon oxide includes silicon oxide that has aggregated and / or otherwise bonded to one another to form closely packed silica oxide agglomerates. In some embodiments, the silicon oxide includes synthetic silica powder. The synthetic silica powder may be a powder that has been agglomerated into loosely packed, easily crumbled, and / or loosely bound aggregates.

[0031] In some embodiments, the silica support comprises silica-alumina, silica-magnesia, silica-zirconia, silica-alumina-boria, silica-aluminum-magnesia, or a combination thereof. In some embodiments, the silica support comprises a plurality of molecular sieves. The plurality of molecular sieves may include large pore and / or mesoporous molecular sieves, such as MCM-41, MCM-48, M41S, or a combination thereof.

[0032] In some embodiments, the silica support is about 300 ml 2 / g~about 700m 2 / g. Surface properties are measured by nitrogen adsorption isotherms collected at 77 K in the region of P / P<0.3 (BET surface area) and P / P>0.95 (pore volume). In some embodiments, the silica support has an average surface area of ​​about 400 m 2 / g~about 600m 2 In some embodiments, the silica support has an average surface area in the range of about 450 m / g. 2 / g~about 550m 2 In some embodiments, the silica support has an average surface area in the range of about 400 m / g. 2 / g~about 600m 2 / g, and the silica support comprises a plurality of spherical silica beads. In some embodiments, the silica support has an average surface area in the range of about 450 m 2 / g~about 550m 2 / g, and the silica support comprises a plurality of spherical silica beads. In some embodiments, the silica support has an average surface area in the range of about 450 m 2 / g ~ approx. 460m 2In some embodiments, the silica support has an average surface area in the range of about 530 m / g. 2 / g ~ approx. 540m 2 / g.

[0033] In some embodiments, the silica support has a relatively high (e.g., 800 m 2 / g). In some embodiments, the silica support has an average surface area of ​​about 800 m 2 / g~approx. 1200m 2 In some embodiments, the average surface area of ​​the silica support is in the range of about 900 m / g. 2 / g ~ approx. 1100m 2 In some embodiments, the average surface area of ​​the silica support is in the range of about 910 m / g. 2 / g ~ approx. 970m 2 In some embodiments, the average surface area of ​​the silica support is in the range of about 950 m / g. 2 In some embodiments, the average surface area of ​​the silica support is in the range of 1000 m / g. 2 / g or greater.

[0034] In some embodiments, the silica support has a density of about 1 g / cm 3 ~About 3g / cm 3 In some embodiments, the silica support has an average pore volume of about 1 g / cm 3 ~Approx. 2.5g / cm 3 In some embodiments, the silica support has an average pore volume of about 1 g / cm 3 ~Approx. 1.5g / cm 3 In some embodiments, the silica support has an average pore volume of about 1 g / cm 3 ~Approx. 2.5g / cm 3 and the silica support comprises a plurality of spherical silica beads.

[0035] In some embodiments, the silica support has a relatively high (e.g., 1.25 g / cm 3In some embodiments, the silica support has an average pore volume of about 1.25 g / cm. 3 ~Approx. 3.50g / cm 3 In some embodiments, the average pore volume of the silica support is about 1.5 g / cm 3 ~About 3.0g / cm 3 In some embodiments, the average pore volume of the silica support is about 2.0 g / cm 3 ~Approx. 2.5g / cm 3 In some embodiments, the average pore volume of the silica support is about 2.20 g / cm 3 ~Approx. 2.5g / cm 3 In some embodiments, the average pore volume of the silica support is 2.0 g / cm 3 The average pore volume and / or average surface area of ​​the silica support can be measured using nitrogen porosimetry.

[0036] In some embodiments, the silica support has an average pore size greater than 70 Å. In some embodiments, the silica support has an average pore size of from about 70 Å to about 150 Å. In some embodiments, the silica support has an average pore size of from about 90 Å to about 110 Å. In some embodiments, the silica support has an average pore size of from about 91 Å to about 108 Å.

[0037] In some embodiments, the silica support has a high average surface area and a high average pore volume, e.g., 800 g / cm 3 Larger average surface area and 1.25g / cm 3 It has a larger average pore volume.

[0038] The silica support may have any desired particle size. In some embodiments, the desired particle size of the silica support is achieved through grinding and / or extrusion. In some embodiments, the desired particle size of the silica support is achieved by classifying the silica support through a sieve. In some embodiments, the average diameter of the silica support is less than 5.0 mm. In some embodiments, the average diameter of the silica support is from about 0.1 mm to about 5.0 mm. In some embodiments, the average diameter of the silica support is from about 0.2 mm to about 4 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of from about 0.3 mm to about 2 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of from about 0.4 mm to about 4 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of from about 0.5 mm to about 2 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of from about 0.5 mm to about 3 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of from about 0.5 mm to about 4 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of about 0.75 mm to about 3.25 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of about 0.5 mm to about 2.5 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of about 1.5 mm to about 3.5 mm. In some embodiments, the silica support comprises a plurality of spherical silica beads having an average diameter of about 2 mm to about 4 mm.

[0039] In some embodiments, the silica support is dried before contacting the silica support with a liquid. In some embodiments, drying the silica support comprises heating the silica support to a temperature of about 100°C to about 850°C. In some embodiments, the temperature is greater than 120°C. In some embodiments, the temperature may be in the range of about 150°C to about 300°C. In some embodiments, the silica support is dried under reduced pressure. In some embodiments, the silica support is dried under a flowing internal gas, such as a stream of nitrogen or a noble gas. In some embodiments, the silica support is dried for about 1 hour to about 48 hours. In some embodiments, the silica support is dried for about 2 hours to about 24 hours.

[0040] The water-soluble organic compounds may be adsorbed onto the silica support. In some embodiments, the silica support comprises less than 3 wt. % carbon based on the weight of the silica support. In some embodiments, the silica support comprises from about 0.05 wt. % to about 3 wt. % carbon based on the weight of the silica support. In some embodiments, the silica support comprises from about 1 wt. % to about 2 wt. % carbon from the adsorbed water-soluble organic compounds and / or other materials. In some embodiments, the carbon content of the silica support is measured using carbon-nitrogen analysis by converting carbon to carbon dioxide at high temperatures. Epoxidation Method

[0041] The catalysts described herein can be used to produce epoxides from olefins. Accordingly, provided herein is a method for olefin epoxidation. The method can include contacting an olefin with the titanated silica catalyst described herein in the presence of an oxidant and under conditions effective to epoxidize the olefin to form an epoxidized olefin.

[0042] The epoxidation processes described herein may include batch epoxidation processes or continuous epoxidation processes.

[0043] In some embodiments, the catalysts described herein result in relatively high conversion of olefins to products. In some embodiments, at least about 35 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein. In some embodiments, at least about 45 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein. In some embodiments, at least about 50 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein. In some embodiments, at least about 55 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein. In some embodiments, at least about 65 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein. In some embodiments, at least about 75 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein. In some embodiments, at least about 85 mol% of the olefins are converted to epoxidized olefins in the epoxidation processes described herein.

[0044] Any oxidant, i.e., oxidizing agent, may be used in the methods described herein. In some embodiments, the oxidizing agent is a hydroperoxide. In some embodiments, the hydroperoxide is an alkyl hydroperoxide. In some embodiments, the alkyl group has 1 to about 12 carbon atoms. In some embodiments, the alkyl group is tert-butyl. In other embodiments, the hydroperoxide is an aralkyl hydroperoxide. In some embodiments, the aralkyl group has 1 to about 24 carbon atoms. In some embodiments, the aralkyl group has about 1 to about 12 carbon atoms. In some embodiments, the aralkyl group is ethylbenzyl or cumyl.

[0045] In some embodiments, the oxidizing agent is an organic hydroperoxide, such as tert-butyl hydroperoxide (TBHP), cumene hydroperoxide (CHP), ethylbenzene hydroperoxide, or 1-ethylbutyl hydroperoxide (EBHP).

[0046] Any olefin may be used in the epoxidation methods described herein. As used herein, the term "olefin" refers to any hydrocarbyl containing at least one non-aromatic double bond, such as C1-C6. 30 The term "olefin" may refer to a hydrocarbyl. In some embodiments, the olefin has 1 to 24 carbon atoms. In some embodiments, the olefin has 1 to 12 carbon atoms. In some embodiments, the olefin is propylene, 1-octene, or a combination thereof. In some embodiments, the olefin is substituted with one or more other functional groups, such as hydroxyl or halide.

[0047] Any ratio of olefin to oxidant may be used in the epoxidation processes described herein, hi some embodiments, the molar ratio of olefin to oxidant is from about 1:1 to about 20:1, or from about 10:1 to about 12:1.

[0048] In some embodiments, at least a portion of the epoxidation reaction is carried out in a liquid phase. In some embodiments, the liquid phase comprises one or more liquids (e.g., one or more solvents) or inert diluents. In some embodiments, the liquid is a hydrocarbon precursor of the hydroperoxide (e.g., either the corresponding alkane or alcohol). For example, if the hydroperoxide is tert-butyl hydroperoxide in some embodiments, an optional liquid may be tert-butanol.

[0049] The epoxidation processes described herein may be modified by adjusting the pressure and / or temperature. In some embodiments, the epoxidation process is carried out, at least in part, at a temperature in the range of about 25°C to about 200°C. In some embodiments, the temperature is in the range of about 50°C to about 160°C. In some embodiments, the temperature is in the range of about 70°C to about 140°C. In some embodiments, the epoxidation process is carried out, at least in part, at about ambient pressure to superatmospheric pressure. In some embodiments, the pressure is in the range of about 20 psi to about 1500 psi. In some embodiments, when propylene is used as the olefin, the pressure is in the range of about 400 psi to about 1000 psi.

[0050] In some embodiments, the epoxidation reaction comprises multiple phases. For example, at least a portion of the reactants may be in the gas phase, and / or at least a portion of the reactants may be in the liquid phase, and / or at least a portion of the catalyst may be in the solid phase. In some embodiments, both reactants are in the liquid phase and the catalyst is in the solid phase, such that the catalyst is used heterogeneously in the reaction mixture.

[0051] In some embodiments, the epoxidation process is carried out in any commercially useful reactor. In some embodiments, the reactor is selected from continuous or batch process reactors. Non-limiting examples of reactors include fixed-bed or slurry reactors. When either of these reactors is used, the reaction may also include separating the reactants and catalyst from the product. In some embodiments, the epoxidation process includes fractional distillation, selective extraction, filtration, and / or similar separation techniques. In some embodiments, at least a portion of any unreacted reactants, liquids, and / or catalyst are recycled to the epoxidation reaction.

[0052] It is intended that singular terms may also include plural alternatives, e.g., at least one alternative. For example, disclosure of "silica support," "olefin," etc., is meant to encompass mixtures or combinations of one or more silica supports, olefins, etc., unless otherwise indicated.

[0053] In this description, the terms "comprises," "is," "contains," "has," and "comprises" are used in an open-ended manner and should be understood to mean "including, but not limited to." When a method or system is claimed or described in terms of "comprising" various components or steps, the method or system may also "consist essentially of" or "consist of" the various components or steps, unless otherwise indicated.

[0054] Various numerical ranges may be disclosed herein. When Applicant discloses or claims any type of range, Applicant's intent is to disclose or claim each individually possible number that such range can reasonably encompass, including the endpoints of the range and any subranges and combinations of subranges therein, unless otherwise indicated. Furthermore, the numerical endpoints of ranges disclosed herein are approximations. As a representative example, Applicant discloses that in one embodiment, a plurality of spherical silica beads have a pore volume of about 1 cc / g to about 2.5 cc / g. This range should be understood to encompass values ​​within the range of about 1 cc / g to about 2.5 cc / g, and further encompass each of "about" 1.1 cc / g, 1.2 cc / g, 1.3 cc / g, 1.4 cc / g, 1.5 cc / g, 1.6 cc / g, 1.7 cc / g, 1.8 cc / g, 1.9 cc / g, 2 cc / g, 2.1 cc / g, 2.2 cc / g, 2.3 cc / g, and 2.4 cc / g, including any ranges and subranges therebetween.

[0055] Throughout this specification, the term "about" is used to indicate that a value includes variations in error for the device or method employed in determining the value, or the variation that exists between studies. The term "about" connotes natural variations in conditions and is used to indicate a plus or minus 5% variation in a value. In some embodiments, this variation is plus or minus 1% of the value.

[0056] The processes described herein may be performed or carried out in any order as desired in various embodiments. Additionally, in certain embodiments, at least a portion of the processes may be performed in parallel. Furthermore, in certain embodiments, fewer or more processes than those described may be performed.

[0057] Many modifications and other embodiments of the disclosure set forth herein will be apparent to those skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the accompanying drawings. It is therefore to be understood that the disclosure is not to be limited to the particular embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. [Example]

[0058] The present disclosure is further illustrated by the following examples, which should not be construed as imposing limitations on its scope in any way. Instead, it should be understood that various other aspects, embodiments, modifications, and equivalents thereof, which will become apparent to those skilled in the art after reading the description set forth herein, can be utilized without departing from the spirit of the disclosure or the scope of the appended claims. Accordingly, other aspects will become apparent to those skilled in the art from consideration of the details and practice of the subject matter disclosed herein. Examples 1 and 2 and Comparative Example (CE) - Titanated Silica Catalyst

[0059] In this example, two titanated silica catalysts were prepared and tested in an epoxidation process.

[0060] In this example, two types of silica carriers were used to prepare titanated silica catalysts. The first silica carrier had an average particle size of about 2 mm to about 3 mm and a particle size of about 455 mm. 2 The second silica support comprised AlphaCat® 4000 silica particles (PQ Corporation, USA), which are spherical particles having an average diameter of about 2 mm to about 3 mm, a surface area of ​​about 1.06 cc / g, and a pore volume of about 533 m. 2 The samples contained AlphaCat® 4000 silica particles (PQ Corporation, USA), which are spherical particles with a surface area of ​​1.2 cc / g and a pore volume of approximately 1.2 cc / g.

[0061] The two silica supports in this example were prepared by treating each silica support with TiCl vapor using standard titanation procedures (see, e.g., U.S. Patent Application No. 10,017,484, incorporated herein by reference). The titanated silica supports were then calcined in air for 2 hours at 700°C, followed by treatment with water vapor and hexamethyldisilazane (HMDS) at 200°C.

[0062] The performance of each of the titanated silica catalysts prepared with AlphaCat® 4000 silica particles in this example was tested in an octene / 1-ethylbutyl hydroperoxide epoxidation process. Octene epoxidation tests were conducted using a POSM oxidant effluent (ethylbenzene, approximately 7-9% EBHP in EB) that had been caustic-scrubbed and treated with CO2 / H2O to remove sodium. The test temperature was 70°C for 3 hours, and 0.05 g of catalyst was used in a mixture of 1 mL of octene and 5 mL of POSM oxidation product.

[0063] For comparative purposes, the performance of a titanated catalyst support prepared by the procedure described above using crushed silica particles was also tested. The results of these tests are presented in the table below. [Table 1]

[0064] The data in Table 1 show that spherical silica particles (i.e., silica beads) perform better in epoxidation reactions than crushed silica particles.

[0065] Reaction conditions for propylene epoxidation in the examples

[0066] The catalyst was also tested under propylene epoxidation conditions. The reactor had an internal diameter of 0.62" and contained a 1 / 8" OD thermocouple sheath and an oil jacket for heating. The reactor pressure was 800 psig. The reactor feed was 50 g / hr of pure propylene and 150 g / hr of caustic-washed and dried EBHP oxidation product (containing approximately 9% EBHP, 88% ethylbenzene, and the remainder being methyl benzyl alcohol and acetophenone). The reactor was heated to convert 50% of the EBHP feed. An axial thermocouple was used to measure the catalyst bed temperature. The reactor contained 3 grams of spherical catalyst as described above in Example 1. After 100 hours on-stream, the catalyst temperature required to convert 50% of the EBHP was 54.4°C (130°F). After 500 hours on-stream, the catalyst temperature required to convert 50% of the EBHP was 76.7°C (170°F). The effluent from this reactor was fed to a second reactor, which contained 6 grams of the same Example 1 catalyst and had the same on-stream time. The temperature of the second reactor was adjusted to convert 99% of the EBHP fed to the first reactor. At 100 hours on-stream, the molar selectivity of propylene oxide produced relative to EBHP consumed in both reactors was 98.0%. At 500 hours on-stream, the molar selectivity of propylene oxide produced relative to EBHP consumed in both reactors was 97.1%. After 550 hours on-stream, the catalyst from Example 1 was removed and its crush strength was measured, averaging 10.4 pounds force.

[0067] A similar test was performed on the catalyst of the comparative example (CE). The operating conditions were the same as in Example 1 above. This catalyst was not spherical, but was made of crushed silica gel with a diameter of approximately 1 mm. After 100 hours on-stream, the 3-gram catalyst bed in the first reactor required 60°C (140°F) to convert 50% of the EBHP fed to it. After 500 hours on-stream, the 3-gram catalyst bed in the first reactor required 82.2°C (180°F) to convert 50% of the EBHP fed to it. The effluent from the first reactor was fed to a second reactor, which contained 6 grams of the same catalyst and had the same on-stream time. The temperature was adjusted to convert 99% of the EBHP. At 100 hours on-stream, the molar selectivity of propylene oxide produced relative to EBHP consumed by both reactors was 96.7%. At 500 hours on-stream, the molar selectivity of propylene oxide produced relative to EBHP consumed by both reactors was 98.0%. After 550 hours on-stream, the comparative example (CE) catalyst was removed and its crush strength was measured, averaging 3.5 lbf.

[0068] The conclusion from these examples is that the spherical catalyst of Example 1 is more active and has a much higher crush strength, as shown in Table 2 below. [Table 2]

Claims

1. 1. A method for preparing a titanated silica catalyst, comprising: providing a silica support comprising a plurality of spherical silica beads; contacting the silica support with a titanium compound to form a titanium-treated silica support; calcining the titanium-treated silica support to form a calcined titanium-treated silica support, wherein calcining the titanium-treated silica support is performed in the absence of oxygen; contacting the calcined titanium-treated silica support with water, steam, or an alcohol to form a water or alcohol adduct of the calcined titanium-treated support; and silylating the water or alcohol adduct of the calcined titanium-treated silica support to form the titanated silica catalyst; and The spherical silica beads have an average diameter of 2 mm to 4 mm, the plurality of spherical silica beads have an average surface area in the range of 400 m 2 / g to 600 m 2 / g; the plurality of spherical silica beads have an average pore volume of 1 cc / g to 2.5 cc / g; The method, wherein the average surface area and the average pore volume are measured by nitrogen adsorption isotherms in the region of P / P<0.3 (BET surface area) and P / P>0.95 (pore volume) collected at 77 K.

2. The titanium compound is titanium tetrachloride (TiCl ４ 2. The method of claim 1 , wherein

3. 2. The method of claim 1, wherein the alcohol is methanol.

4. The plurality of spherical silica beads has a diameter of about 450 m ２ / g ~ approx. 550m ２ 10. The method of claim 1, wherein the surface area of ​​the sintered body is in the range of 1 / g.

5. 10. The method of claim 1, wherein the plurality of spherical silica beads has an average pore volume of about 1 cc / g to about 1.5 cc / g.

6. 10. The method of claim 1, wherein said calcining said titanium-treated silica support comprises heating said titanium-treated silica support in air to a temperature of from about 500°C to about 750°C for from about 1 hour to about 3 hours.

7. The silylation of the calcined titanium-treated silica support converts the calcined titanium-treated silica support to a compound having the formula: R ３ SiNHSiR' ３ wherein each R and R′ is independently a monovalent C １ ~C ６ 10. The method of claim 1, comprising contacting the organodisilazane with an organodisilazane selected from the group consisting of methyl, ...

8. The method of claim 7 wherein the organodisilazane is hexamethyldisilazane.

9. 1. A process for olefin epoxidation comprising: Providing a titanated silica catalyst prepared by the method of claim 1; and a process comprising contacting said olefin with said titanated silica catalyst in the presence of an oxidant and under conditions effective to form an epoxidized olefin.

10. 10. The method of claim 9, wherein the olefin comprises propylene.

11. 10. The method of claim 9, wherein the oxidant comprises a hydroperoxide.

12. 12. The method of claim 11, wherein the hydroperoxide comprises 1-ethylbutyl hydroperoxide (EBHP), t-butyl hydroperoxide (TBHP), or cumene hydrogen peroxide (CHP).

13. 10. The process of claim 9, wherein about 20 mol % to 100 mol % of the olefin is converted to the epoxidized olefin.

14. 10. The process of claim 9, wherein about 45 mol % to 100 mol % of the olefin is converted to the epoxidized olefin.

15. 10. The process of claim 9, wherein about 85 mol % to 100 mol % of the olefin is converted to the epoxidized olefin.

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