A titanium silicon catalytic material and its preparation method and application

Abstract

The present invention belongs to the technical field of vicinal diol compound preparation, and in particular to a titanium silicon catalytic material and its preparation method and application. The preparation method comprises the following steps: S1, a mixture of a silicon source, a titanium source, a structure directing agent, a monosaccharide compound, and water is hydrolyzed and dispersed to obtain a mixed system I; S2, the mixed system I is added to a concentration kettle, and the water-silicon ratio of the mixed system I is reduced by distillation and dehydration to obtain a mixed system II; S3, the mixed system II is transferred to a closed crystallization kettle, and is hydrothermally reacted under autogenous pressure to obtain titanium silicon molecular sieve TS-1; S4, a mixture of a silicon source, a titanium source, an alkali source and water is hydrolyzed and dispersed to obtain an amorphous titanium silica gel precursor; S5, an amorphous titanium silica gel precursor, titanium silicon molecular sieve TS-1 and sesbania powder are mixed, and the titanium silicon catalytic material is obtained by kneading, forming, drying and roasting. The titanium silicon catalytic material obtained by the present invention is a heterogeneous catalytic material with a double Lewis active center, which can be used for one-step catalytic olefin preparation of vicinal diol compounds.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of vicinal diol compounds, and particularly relates to a titanium silicon catalytic material, a preparation method thereof and application in the synthesis of vicinal diol compounds. Background Art

[0002] Vicinity diol compounds, such as ethylene glycol, 1,2-propylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol, are an important class of fine chemicals. Because they are non-corrosive and can dissolve a variety of active ingredients, they are widely used in cosmetics such as skin creams, eye creams, lotions, baby care products, and sunscreen products.

[0003] The preparation of vicinal diols is typically achieved through a two-step synthesis process, where an olefin is first oxidized to form an epoxide, which is then hydrolyzed under acid or base catalysis to produce the corresponding vicinal diol. However, the hydrolysis reaction requires a high water-to-hydrocarbon ratio, which means that a large amount of water is required to circulate the reaction, increasing the energy consumption and cost of vicinal diol production. Therefore, a more economical vicinal diol production process is urgently needed.

[0004] Against this backdrop, patent CN107879893 B discloses a method for preparing vicinal diol compounds. This method simplifies the two-step synthesis process, using titanium silicalite and SAPO-11 molecular sieves as active components and alumina as a binder to prepare a bifunctional catalytic material with both epoxidation and hydrolysis properties, enabling the single-step catalytic conversion of olefins to vicinal diols. However, this bifunctional catalytic material suffers from poor oxidant selectivity, resulting in low olefin conversion and low vicinal diol yields. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a titanium silicon catalyst material, which is achieved through the following technical solutions:

[0006] A method for preparing a titanium silicon catalyst material comprises the following steps:

[0007] S1, hydrolyzing and dispersing a mixture of a silicon source, a titanium source, a structure-directing agent, a monosaccharide compound, and water to obtain a mixed system I;

[0008] S2, adding the mixed system I to the concentration kettle, and reducing the water-silicon ratio of the mixed system I by distillation and dehydration to obtain the mixed system II;

[0009] S3, transferring the mixed system II to a closed crystallization reactor, and subjecting it to a hydrothermal reaction under autogenous pressure to obtain titanium silicate molecular sieve TS-1;

[0010] S4, hydrolyzing and dispersing the mixture of the silicon source, the titanium source, the alkali source and water to obtain an amorphous titanium silica gel precursor;

[0011] S5. Mixing an amorphous titanium silica gel precursor, titanium silicate molecular sieve TS-1 and sesbania powder, and obtaining a titanium silicate catalytic material through kneading, molding, drying and calcining.

[0012] During the preparation of the titanium silicon molecular sieve TS-1 of the present invention, by regulating the water-silicon ratio and introducing monosaccharide compounds into the mixed system I, because the monosaccharide compounds have abundant hydroxyl groups, they can form hydrogen bonds with the silicon / titanium hydroxyl groups in the molecular sieve precursor, affecting the growth process of the molecular sieve grains, improving the distribution uniformity of the molecular sieve grain size, and having a certain effect on its morphology and crystal orientation; at the same time, the hydrogen bonding effect can also inhibit the self-aggregation of the titanium species in the precursor to form anatase-type non-framework titanium species. On the other hand, the lower the water-silicon ratio of the precursor mixture, the faster the mass transfer and diffusion of the molecular sieve precursor, and the easier it is to form molecular sieve particles with more uniform size.

[0013] Furthermore, the present invention constructs a heterogeneous catalytic material with dual Lewis active centers by mixing an amorphous titanium silicalite precursor, titanium silicalite TS-1, and sesbania powder. The tetracoordinated framework titanium in the heteroatom molecular sieve TS-1 acts as an active center for activating the oxidant and catalyzing the epoxidation of olefins to epoxides. The binder, composed of the amorphous titanium silicalite, contains penta- or hexacoordinated titanium species. Because these penta- or hexacoordinated titanium species are more acidic than tetracoordinated titanium, they catalyze the hydration of epoxides to form diols.

[0014] Preferably, the silicon source in S1 and S4 is selected from at least one of organic silicate, silica gel, white carbon black, and silica sol; in order to reduce the influence of heteroatoms in the silicon source on the catalyst crystallization product, a single silicon source is preferred; further preferred is organic silicate, such as at least one of methyl orthosilicate, isopropyl silicate, ethyl silicate, tetraethoxysilane, and tetraethyl orthosilicate.

[0015] Preferably, the titanium source in S1 and S4 is selected from at least one of organic titanium esters and / or inorganic titanium salts such as titanium tetrachloride, tetrabutyl titanate, tetraethyl titanate, and titanium tetrafluoride; preferably, the titanium source is at least one of tetrabutyl titanate and tetraethyl titanate.

[0016] Preferably, the structure directing agent in S1 is selected from at least one of quaternary ammonium base, quaternary ammonium salt, aliphatic amine and aliphatic alcohol amine.

[0017] Specifically, the general structural formula of the quaternary ammonium hydroxide is:

[0018]

[0019] Wherein, R1, R2, R3, and R4 are each at least one C1-C4 alkyl group, wherein the C1-C4 alkyl group is selected from at least one of a C1-C4 linear alkyl group and a C3-C4 branched alkyl group. R1, R2, R3, and R4 can independently be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0020] Specifically, the general structural formula of the quaternary ammonium salt is:

[0021]

[0022] Wherein, R1, R2, R3, and R4 are each at least one C1-C4 alkyl group, and the C1-C4 alkyl group is selected from at least one of a C1-C4 linear alkyl group and a C3-C4 branched alkyl group. R1, R2, R3, and R4 can independently be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl group; and X in the quaternary ammonium salt is at least one halogen ion selected from F, Cl, Br, I, and the like.

[0023] The general structural formula of the aliphatic amine is R5(NH2)n, where n is an integer of 1 or 2. When n is 1, R5 is at least one C1-C6 alkyl group, and the C1-C6 alkyl group is selected from at least one of a C1-C6 straight-chain alkyl group and a C3-C6 branched-chain alkyl group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl, or n-hexyl group. When n is 2, R5 is at least one C1-C6 alkylene group, and the C1-C6 alkylene group is selected from at least one of a C1-C6 straight-chain alkylene group and a C3-C6 branched-chain alkylene group, such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, or n-hexylene.

[0024] The general structural formula of the aliphatic alcohol amine is R6(ONH)n, wherein n is an integer of 1 or 2. When n is 1, R6 is at least one C1-C6 alkyl group, and the C1-C6 alkyl group is selected from at least one of a C1-C6 straight-chain alkyl group and a C3-C6 branched-chain alkyl group, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl, or n-hexyl group. When n is 2, R6 is at least one C1-C6 alkylene group, and the C1-C6 alkylene group is selected from at least one of a C1-C6 straight-chain alkylene group and a C3-C6 branched-chain alkylene group, such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, or n-hexylene.

[0025] Preferably, the structure directing agent is selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tripropylamine, triethylamine, diethylamine, tributylamine, and hexylenediamine. More preferably, the structure directing agent is selected from at least one of tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrapropylammonium chloride.

[0026] Preferably, the monosaccharide compound includes at least one of aldoses and ketoses such as aldotrose, acetose, aldotreose, ketutose, erythrose, threose, ribose, arabinose, fructose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, and talose; further preferably, the monosaccharide compound is at least one of fructose and glucose.

[0027] Preferably, the molar ratio of the silicon source, titanium source, structure directing agent, monosaccharide compound and water in the mixed system I is 1: (0.0001-0.025): (0.05-0.5): (0.01-3): (20-100), and the silicon source and titanium source are calculated as SiO2 and TiO2, respectively.

[0028] Preferably, the distillation dehydration in S2 refers to discharging water vapor through the exhaust valve of the concentration kettle under autogenous pressure of 80-100° C. to reduce the water-silicon ratio of the mixed system I.

[0029] Preferably, the water-silicon ratio in S2 is 1:(3-15), where the water-silicon ratio is calculated based on SiO2 and water.

[0030] Preferably, the hydrothermal reaction conditions in S3 are 120-190° C. for 6-96 h.

[0031] Preferably, the alkaline source in S4 includes at least one of organic bases and inorganic bases such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, sodium hydroxide, potassium hydroxide, and cesium hydroxide; further preferably, the alkaline source is tetramethylammonium hydroxide.

[0032] Preferably, the molar ratio of the silicon source, titanium source, alkali source and water in S4 is 1: (0.026-0.4): (0.1-2): (20-200).

[0033] Preferably, the weight ratio of the oxide, titanium silicate molecular sieve TS-1 and sesbania powder in the amorphous titanium silicalite precursor in S5 is 1:(0.1-0.4):(0.005-0.1).

[0034] The second object of the present invention is to provide a titanium silicon catalytic material, which is prepared by any one of the above preparation methods.

[0035] As a further preference, in the titanium silicon catalytic material, the molar ratio of tetracoordinate titanium to penta / hexacoordinate titanium is 1:(0.13-300).

[0036] The third object of the present invention is to propose the use of the above-mentioned titanium silicon catalyst material in catalyzing olefin epoxidation reactions.

[0037] Preferably, the olefin epoxidation reaction uses titanium silicon catalyst material as catalyst and hydrogen peroxide as oxidant, and at 40-80°C and 0.5-5MPa, the titanium silicon catalyst material, hydrogen peroxide, olefin and water are contacted and reacted in a reactor to obtain vicinal diol compounds.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present invention introduces monosaccharide compounds and regulates the water-silicon ratio during the preparation process of titanium silicalite TS-1. On the one hand, the size of the heteroatom molecular sieve TS-1 grains can be reduced, the uniformity of its size can be improved, and the formation of anatase-type non-framework titanium species can be inhibited.

[0040] (2) The present invention adopts an amorphous titanium silica gel binder to construct a double Lewis acid center catalytic material having both a tetracoordinated skeleton titanium epoxidation active center and a penta / hexacoordinated titanium hydration reaction center, which can realize the one-step efficient and highly selective reaction of olefins to synthesize diol compounds; and because the penta / hexacoordinated titanium species have very good hydrothermal stability, the activity stability of the catalyst is good. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the specification and specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only a portion of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0042] The unified preparation method of the titanium silicon catalyst material in the following embodiments is:

[0043] S1, hydrolyzing and dispersing a mixture of a silicon source, a titanium source, a structure-directing agent, a monosaccharide compound, and water at 60° C. for 8 h to obtain a mixed system I;

[0044] S2, adding the mixed system I to the concentration kettle, and reducing the water-silicon ratio of the mixed system I by distillation and dehydration to obtain the mixed system II;

[0045] S3, transferring the mixed system II to a closed crystallization reactor, and subjecting it to a hydrothermal reaction under autogenous pressure to obtain titanium silicate molecular sieve TS-1;

[0046] S4, hydrolyzing and dispersing a mixture of a silicon source, a titanium source, an alkali source and water at 60° C. for 8 hours to obtain an amorphous titanium silica gel precursor;

[0047] S5. Mix the amorphous titanium silica gel precursor, titanium silicate molecular sieve TS-1 and sesbania powder, knead and shape, dry at 110° C. for 10 h, and calcine at 550° C. for 4 h to obtain a titanium silicate catalytic material.

[0048] In the following examples, the unified method for preparing vicinal diol compounds using titanium silicon catalyst materials to catalyze olefins is as follows:

[0049] Using titanium silicon catalytic material as catalyst and hydrogen peroxide as oxidant, at a certain temperature and pressure (see the table below for details), titanium silicon catalytic material, hydrogen peroxide, olefins and water are brought into contact in a reactor and react to obtain epoxy compounds.

[0050] Examples 1 to 3

[0051] The raw materials, raw material ratios and preparation conditions for preparing titanium silicate molecular sieve TS-1 in Examples 1 to 3 are detailed in Table 1 below.

[0052] Table 1. Relevant parameters for the preparation of titanium silicate molecular sieve TS-1 in Examples 1 to 3

[0053]

[0054]

[0055] Examples 4 to 6

[0056] The raw materials, raw material ratios and preparation conditions for preparing titanium silicate molecular sieve TS-1 in Examples 4 to 6 are detailed in Table 2 below.

[0057] Table 2. Parameters related to the preparation of titanium silicate molecular sieve TS-1 in Examples 4 to 6

[0058]

[0059]

[0060] Examples 7 to 9

[0061] The raw materials, raw material ratios and preparation conditions for preparing titanium silicate molecular sieve TS-1 in Examples 7 to 9 are detailed in Table 3 below.

[0062] Table 3. Parameters related to the preparation of titanium silicate molecular sieve TS-1 in Examples 7 to 9

[0063]

[0064]

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that no monosaccharide compound is added. The rest is the same as Example 1 and will not be described in detail in this section.

[0067] Comparative Example 2

[0068] The difference between Comparative Example 2 and Example 1 is that the water-silicon ratio is not adjusted. The rest is the same as Example 1 and will not be described in detail in this section.

[0069] Comparative Example 3

[0070] The difference between Comparative Example 3 and Example 1 is that S4 and S5 are not performed, and the rest is the same as Example 1, which will not be described in detail in this section.

[0071] Performance Testing

[0072] The following parameters of Examples 1 to 9 and Comparative Examples 1 to 3 were measured, and the specific measurement methods are as follows: the grain size was measured by scanning electron microscopy (SEM), and the size of no less than 100 molecular sieve particles was measured. The Q4:Q5&6 measurement method is: the state of titanium is tested by ultraviolet spectrophotometer, and the peak area ratio is obtained based on the peak fitting of the characteristic peaks of tetracoordinated, penta / hexacoordinated titanium. The calculation formulas for Q4:Q5&6, hydrogen peroxide conversion rate, hydrogen peroxide selectivity, vicinal diol selectivity, and epoxy compound selectivity are as follows:

[0073] Q4:

[0074]

[0075]

[0076]

[0077]

[0078] The table obtained through calculation and integration is as follows:

[0079] Table 4. Performance test results

[0080]

[0081] As can be seen from the table above, the titanium-silicon catalyst material prepared in this invention exhibits excellent catalytic performance, achieving high levels of hydrogen peroxide conversion and selectivity. Specifically, the heterogeneous catalytic material, constructed with dual Lewis active centers, can be used to catalyze the production of vicinal diols from olefins in a single step, achieving higher yields of vicinal diols than those produced using existing technologies.

Claims

1. A method for preparing a titanium silicon catalyst material, characterized in that: The following steps are involved: S1, hydrolyzing and dispersing a mixture of a silicon source, a titanium source, a structure-directing agent, a monosaccharide compound, and water to obtain a mixed system I; S2, adding the mixed system I to the concentration kettle, and reducing the water-silicon ratio of the mixed system I by distillation and dehydration to obtain the mixed system II; S3, transferring the mixed system II to a closed crystallization reactor, and subjecting it to a hydrothermal reaction under autogenous pressure to obtain titanium silicate molecular sieve TS-1; S4, hydrolyzing and dispersing the mixture of the silicon source, the titanium source, the alkali source and water to obtain an amorphous titanium silica gel precursor; S5. Mixing an amorphous titanium silica gel precursor, titanium silicate molecular sieve TS-1 and sesbania powder, and obtaining a titanium silicate catalytic material through kneading, molding, drying and calcining.

2. The method for preparing the titanium silicon catalytic material according to claim 1, characterized in that: The monosaccharide compound includes at least one of aldose and ketose.

3. The method for preparing the titanium silicon catalytic material according to claim 2, characterized in that: The monosaccharide compound includes at least one of aldotrigose, acetose, aldotreose, ketutose, erythrose, threose, ribose, arabinose, fructose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, and talose.

4. The method for preparing the titanium silicon catalytic material according to claim 1, characterized in that: The molar ratio of the silicon source, titanium source, structure directing agent, monosaccharide compound and water in the mixed system I is 1: (0.0001-0.025): (0.05-0.5): (0.01-3): (20-100), and the silicon source and titanium source are calculated as SiO2 and TiO2, respectively.

5. The method for preparing the titanium silicon catalytic material according to claim 1, characterized in that: The distillation dehydration in S2 refers to the discharge of water vapor through the exhaust valve of the concentration kettle at an autogenous pressure of 80 to 100° C. to reduce the water-silicon ratio of the mixed system I to 1: (3 to 15), where silicon is calculated as SiO2.

6. The method for preparing the titanium silicon catalytic material according to claim 1, characterized in that: The molar ratio of the silicon source, titanium source, alkali source and water in S4 is 1: (0.026-0.4): (0.1-2): (20-200).

7. The method for preparing the titanium silicon catalytic material according to claim 1, characterized in that: The weight ratio of the amorphous titanium silica gel precursor, titanium silicate molecular sieve TS-1 and sesbania powder in S5 is 1: (0.1 to 0.4): (0.005 to 0.1).

8. A titanium silicon catalytic material, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 7.

9. The titanium silicon catalytic material according to claim 8, characterized in that The molar ratio of tetracoordinate titanium to penta / hexacoordinate titanium is 1:(0.13~300).

10. Use of the titanium silicon catalytic material obtained by the preparation method according to any one of claims 1 to 7 or the titanium silicon catalytic material according to claim 8 or claim 9 in the preparation of vicinal diol compounds.

11. The use according to claim 10, characterized in that With titanium silicon catalytic material as catalyst and hydrogen peroxide as oxidant, titanium silicon catalytic material, hydrogen peroxide, olefin and water are brought into contact in a reactor at 40-80°C and 0.5-5MPa and react to obtain vicinal diol compounds.

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