CN110642263A - Tin-titanium-silicon molecular sieve, preparation method and application thereof, and thioether oxidation method - Google Patents

Tin-titanium-silicon molecular sieve, preparation method and application thereof, and thioether oxidation method Download PDF

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CN110642263A
CN110642263A CN201810671998.6A CN201810671998A CN110642263A CN 110642263 A CN110642263 A CN 110642263A CN 201810671998 A CN201810671998 A CN 201810671998A CN 110642263 A CN110642263 A CN 110642263A
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molecular sieve
titanium
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史春风
林民
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Sinopec Research Institute of Petroleum Processing
China Petrochemical Corp
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China Petrochemical Corp
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    • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
    • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
    • C01B39/06—Preparation of isomorphous zeolites characterised by measures to replace the aluminium or silicon atoms in the lattice framework by atoms of other elements, i.e. by direct or secondary synthesis
    • C01B39/08—Preparation of isomorphous zeolites characterised by measures to replace the aluminium or silicon atoms in the lattice framework by atoms of other elements, i.e. by direct or secondary synthesis the aluminium atoms being wholly replaced
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    • B01J29/00—Catalysts comprising molecular sieves
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
    • C01B39/06—Preparation of isomorphous zeolites characterised by measures to replace the aluminium or silicon atoms in the lattice framework by atoms of other elements, i.e. by direct or secondary synthesis
    • C01B39/08—Preparation of isomorphous zeolites characterised by measures to replace the aluminium or silicon atoms in the lattice framework by atoms of other elements, i.e. by direct or secondary synthesis the aluminium atoms being wholly replaced
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    • C07C315/00—Preparation of sulfones; Preparation of sulfoxides
    • C07C315/02—Preparation of sulfones; Preparation of sulfoxides by formation of sulfone or sulfoxide groups by oxidation of sulfides, or by formation of sulfone groups by oxidation of sulfoxides

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Abstract

The invention relates to the field of molecular sieves, and discloses a tin-titanium-silicon molecular sieve, a preparation method and application thereof, and a thioether oxidation method, wherein the molecular sieve comprises the following components: tin, titanium, silicon and oxygen, the molecular sieve satisfies X1‑1.8/X0.4‑0.9＝C，0.3<C<0.85，X0.4‑0.9The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X1‑1.8Is a micropore with a molecular sieve in the range of 1-1.8nmThe diameter accounts for the proportion of the pore size distribution of the total micropores. The method comprises the following steps: mixing a catalyst containing a titanium silicalite molecular sieve with an acid solution to obtain a mixture A, and carrying out first heat treatment on the mixture A to obtain a first solid; mixing the first solid, the tin source, the silicon source, the alkali source and the water, and carrying out second heat treatment. The tin-titanium-silicon molecular sieve provided by the invention has a special physical and chemical characteristic structure, is used for thioether oxidation reaction, and is favorable for regulating the selectivity of a target product.

Description

Tin-titanium-silicon molecular sieve, preparation method and application thereof, and thioether oxidation method
Technical Field
The invention relates to the field of molecular sieves, in particular to a tin-titanium-silicon molecular sieve, a preparation method of the tin-titanium-silicon molecular sieve, application of the tin-titanium-silicon molecular sieve in thioether oxidation reaction and a thioether oxidation method.
Background
The titanium-silicon molecular sieve is a molecular sieve with a framework composed of silicon, titanium and oxygen elements, and has wide application prospect in petroleum refining and petrochemical industry. Wherein, the TS-1 molecular sieve is a novel titanium silicalite molecular sieve with excellent catalytic selective oxidation performance formed by introducing a transition metal element titanium into a molecular sieve framework with a ZSM-5 structure.
TS-1 not only has the catalytic oxidation effect of titanium, but also has the shape-selective effect and excellent stability of a ZSM-5 molecular sieve, and successfully realizes industrial application in the process of preparing cyclohexanone oxime by performing catalytic ammoxidation on cyclohexanone. However, generally, the catalytic performance of the catalyst deteriorates after a certain period of operation, and the catalyst undergoes deactivation. Inactivation is further classified into temporary inactivation and permanent inactivation. A temporarily deactivated catalyst may be regenerated to restore some or all of its activity, while a permanently deactivated catalyst may not be regenerated to restore activity (activity after regeneration is less than 50% of the original activity). The titanium-silicon molecular sieve can not be recycled at present after the inactivation of the titanium-silicon molecular sieve in an alkaline environment, particularly the permanent inactivation of the ammoximation catalyst TS-1, and is mainly treated by adopting a stacking and burying mode. Thus, precious land resources and storage space are occupied, and the development of a technology for recycling the deactivated ammoximation catalyst is urgently needed.
Sulfones are important sulfur-containing compounds, such as dimethyl sulfone, which is a white crystalline powder, readily soluble in water, ethanol, benzene, methanol and acetone, and slightly soluble in ethers. Dimethyl sulfone is industrially used as a high-temperature solvent and raw material for organic synthesis, a gas chromatography stationary liquid, an analytical reagent, a food additive, and a drug. Dimethyl sulfone, as an organic sulfide, has the functions of enhancing the human body's ability to produce insulin, and promoting the metabolism of saccharides, and is an essential substance for the synthesis of human collagen.
Sulfones are important sulfur-containing compounds, such as dimethyl sulfone, which is a white crystalline powder, readily soluble in water, ethanol, benzene, methanol and acetone, and slightly soluble in ethers. Dimethyl sulfone is industrially used as a high-temperature solvent and raw material for organic synthesis, a gas chromatography stationary liquid, an analytical reagent, a food additive, and a drug. Dimethyl sulfone, as an organic sulfide, has the functions of enhancing the human body's ability to produce insulin, and promoting the metabolism of saccharides, and is an essential substance for the synthesis of human collagen.
At present, the sulfone can be prepared by a thioether oxidation method, and when the thioether is oxidized by an oxidizing agent (especially peroxide), the oxidation product is mainly a mixture of sulfoxide and sulfone. Therefore, modulating the selectivity of the target product according to the production needs is an important research content in the thioether oxidation process.
Disclosure of Invention
The invention aims to provide a tin-titanium-silicon molecular sieve with special physical and chemical characteristics, a preparation method and application thereof, and a thioether oxidation method. The tin-titanium-silicon molecular sieve provided by the invention is used for catalyzing thioether oxidation reaction, and can effectively improve the selectivity of sulfone.
The inventor characterizes the physicochemical properties of the inactivated titanium silicalite molecular sieve, particularly the inactivated titanium silicalite molecular sieve such as an ammoximation catalyst under an alkaline environment after permanent inactivation, and finds that the crystal framework of the inactivated titanium silicalite molecular sieve is basically kept intact and can be utilized. The inventors have further found through extensive research that, in the preparation process of the tin-titanium-silicon molecular sieve, a deactivated titanium-silicon molecular sieve catalyst (especially a titanium-silicon molecular sieve catalyst which is permanently deactivated under an alkaline condition, such as a deactivated cyclohexanone oximation catalyst, is used as a main raw material), and a catalyst with special physicochemical characteristics can be obtained again through specific preparation steps (using acid and alkali (in the presence of a silicon source) for sequential treatment combined with heat treatment, calcination and the like), and the catalyst has excellent catalytic oxidation performance, and can effectively adjust the selectivity of the target product sulfone particularly in the thioether oxidation reaction.
In order to achieve the above object, a first aspect of the present invention provides a tin-titanium-silicon molecular sieve comprising: tin element, titanium element, silicon element and oxygen element, wherein the molecular sieve satisfies X1-1.8/X0.4-0.9＝C，0.3<C<0.85，X0.4-0.9The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X1-1.8Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1-1.8nm in the distribution quantity of the pore diameter of the total micropores.
In a second aspect, the present invention provides a method for preparing a tin-titanium-silicon molecular sieve, the method comprising:
(1) mixing a catalyst containing a titanium silicalite molecular sieve with an acid solution to obtain a mixture A, carrying out first heat treatment on the mixture A under a closed condition, and separating to obtain a first solid;
(2) and mixing the first solid, a tin source, a silicon source, an alkali source and water to obtain a mixture B, and carrying out second heat treatment on the mixture B under a closed condition.
Preferably, the silicon source is at least one selected from organic silicon sources, and more preferably, the hydrolysis rate of the organic silicon source is 40-60%. The tin-titanium-silicon molecular sieve prepared by the preferred embodiment has higher selectivity of sulfone when used for oxidizing thioether.
In a third aspect, the invention provides a tin-titanium-silicon molecular sieve prepared by the preparation method.
The fourth aspect of the present invention provides the use of the above-described tin-titanium-silicon molecular sieve in a thioether oxidation reaction.
In a fifth aspect, the present invention provides a thioether oxidation process comprising: under the condition of oxidizing the thioether, a liquid mixture is contacted with a catalyst, wherein the liquid mixture contains the thioether, at least one oxidant and at least one solvent, and the catalyst contains the tin-titanium-silicon molecular sieve.
The tin-titanium-silicon molecular sieve with the special physical and chemical characteristic structure is used for the reaction of thioether oxidation, and can obtain better catalytic effect. I.e. because the material of the invention has a range of 1-1.8nmPore size distribution of micropores, and X1-1.8/X0.4-0.9＝C，0.3<C<0.85, the catalyst is beneficial to the diffusion of reactant and product molecules in the catalytic reaction, is beneficial to the thioether oxidation reaction, and can effectively modulate the selectivity of a target product.
The method for preparing the tin-titanium-silicon molecular sieve can prepare the tin-titanium-silicon molecular sieve with the special characteristic structure, such as micropore size distribution in the range of 1-1.8 nm. Under the preferable condition of the invention, in the alkali treatment process, an organic silicon source is introduced, so that the surface silicon-titanium ratio of the obtained tin-titanium-silicon molecular sieve is not lower than the bulk silicon-titanium ratio, and the obtained tin-titanium-silicon molecular sieve is used for the reaction of thioether oxidation, thereby being more beneficial to effectively regulating the selectivity of a target product.
The tin-titanium-silicon molecular sieve provided by the invention has a special physicochemical characteristic structure, is used for thioether oxidation reaction, and is favorable for regulating the selectivity of a target product (sulfone).
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The invention provides a tin-titanium-silicon molecular sieve, which comprises a tin element, a titanium element, a silicon element and an oxygen element, wherein the molecular sieve satisfies X1-1.8/X0.4-0.9＝C，0.3<C<0.85，X0.4-0.9The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X1-1.8Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1-1.8nm in the distribution quantity of the pore diameter of the total micropores.
According to a preferred embodiment of the invention 0.35< C < 0.7. The tin-titanium-silicon molecular sieve provided by the invention has pore diameter distribution within the range of 0.4-0.9nm and also has distribution within the range of 1-1.8nm, the ratio of the proportion of the pore diameter of micropores within the range of 1-1.8nm to the total pore diameter distribution of micropores within the range of 0.4-0.9nm is C, 0.3< C <0.85, preferably 0.35< C < 0.7. When the molecular sieve of the preferred technical scheme is used for thioether oxidation reaction, the molecular sieve is more beneficial to the diffusion of reactant and product molecules in the catalytic reaction, not only can the conversion rate of thioether be further improved, but also the selectivity of a target product (such as sulfone) can be more effectively modulated. In the present invention, the pore size distribution was measured on an ASAP2405 static nitrogen adsorber from Micromeritics.
In the present invention, the elemental compositions of tin, titanium and silicon of the samples were measured on a 3271E model X-ray fluorescence spectrometer, manufactured by Nippon Denshi electric motors Co.
In the present invention, the surface Si/Ti ratio was measured by an ESCALB 250 type X-ray photoelectron spectrometer manufactured by Thermo Scientific Co., Ltd, and the bulk Si/Ti ratio was measured by a 3271E type X-ray fluorescence spectrometer manufactured by Nippon Kikusan Kogyo Kaisha.
In the invention, the Fourier transform infrared absorption spectrum of a sample is measured on a Nicolet 8210 type Fourier infrared spectrometer, KBr tablets (the sample accounts for 1 wt%) are adopted under vacuum, and the test range is 400-1400cm-1。
It is to be noted that, in particular, if the proportion of the pore size distribution of the micropores to the total pore size distribution of the micropores is in the range of 1 to 1.8nm<At 1%, the pore distribution of the micropores is negligible, i.e. no micropore distribution in the range of 1-1.8nm is considered, as known to the person skilled in the art. Thus, the invention is described in N2The pore diameter of the micropores in the range of 1-1.8nm in the static adsorption test refers to the proportion of the pore diameter distribution of the micropores in the range of 1-1.8nm to the total pore diameter distribution>1 percent. The microporous molecular sieve prepared by conventional direct hydrothermal synthesis has the ratio of the micropore size distribution to the total micropore size distribution in the range of 1-1.8nm<1 percent of microporous molecular sieve which is treated and modified by a common treatment and modification method and has a lower proportion of the distribution of the pore diameters of the micropores in the range of 1-1.8nm in the distribution of the pore diameters of the total micropores, namely<10%, typically<1％。
According to a preferred embodiment of the present invention, the molecular sieve satisfies nSn/nTi ═ A, I960/I800＝B，B＝i (A +1) nTi, of which 0.1<A<10，0.2<B<1，0<I, nSn is the molar weight of tin element in the molecular sieve, nTi is the molar weight of titanium element in the molecular sieve, I960The infrared absorption spectrum of the molecular sieve is 960cm-1Absorption intensity in the vicinity, I800The infrared absorption spectrum of the molecular sieve is 800cm-1Absorption strength in the vicinity. Preferably, 0.2<A<3，0.3<B<0.7. Therefore, the method is more favorable for diffusion of reactant and product molecules in the catalytic oxidation reaction, not only can further improve the conversion rate of thioether, but also can more effectively modulate the selectivity of a target product. For example, when the catalyst is used in a thioether oxidation reaction, the conversion rate of thioether can be further improved, and the selectivity of the target product sulfone can be more effectively modulated.
The molecular sieve according to the invention, preferably said molecular sieve satisfies Tw/Tk＝D，0.2<D<0.6, further preferably 0.2<D<0.45, wherein, TwIs the micropore volume of the molecular sieve, TkIs the total pore volume of the molecular sieve.
According to the molecular sieve of the invention, preferably, the ratio of silicon element: titanium element: the molar ratio of tin elements is 100: (0.1-10): (0.01-5), preferably 100: (0.2-5): (0.1 to 3.5), more preferably 100: (0.5-4.8): (0.2-2.5), most preferably 100: (1.9-4.1): (0.7-2.2).
According to the tin-titanium-silicon molecular sieve, preferably, the surface silicon-titanium ratio of the molecular sieve is not lower than the bulk silicon-titanium ratio, wherein the silicon-titanium ratio refers to the molar ratio of silicon oxide to titanium oxide; further preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2 or more; more preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2-5; still more preferably, the ratio of the surface silicon to titanium ratio to the bulk silicon to titanium ratio is 2 to 4.5.
The tin-titanium-silicon molecular sieve has the advantages of micropore size distribution in the range of 1-1.8nm, and preferably, the surface silicon-titanium ratio is not lower than the bulk silicon-titanium ratio. The invention has no special requirements on the preparation method of the tin-titanium-silicon molecular sieve, and the tin-titanium-silicon molecular sieve with the structure can be prepared.
The invention also provides a preparation method of the tin-titanium-silicon molecular sieve, which comprises the following steps:
(1) mixing a catalyst containing a titanium silicalite molecular sieve with an acid solution to obtain a mixture A, carrying out first heat treatment on the mixture A under a closed condition, and separating to obtain a first solid;
(2) and mixing the first solid, a tin source, a silicon source, an alkali source and water to obtain a mixture B, and carrying out second heat treatment on the mixture B under a closed condition.
According to the present invention, the catalyst containing the titanium silicalite molecular sieve may contain fresh titanium silicalite molecular sieve, or may be a discharging agent containing titanium silicalite molecular sieve, and the present invention is not particularly limited thereto. However, from the viewpoint of cost control, etc., it is preferable that the catalyst containing the titanium silicalite molecular sieve is a titanium silicalite discharging agent in order to save cost.
The titanium silicalite discharging agent may be discharged from various apparatuses using a titanium silicalite as a catalyst, for example, from an oxidation reaction apparatus using a titanium silicalite as a catalyst. The oxidation reaction may be various oxidation reactions, for example, the discharging agent of the reaction apparatus using the titanium silicalite molecular sieve as the catalyst may be one or more of a discharging agent of an ammoximation reaction apparatus, a discharging agent of a hydroxylation reaction apparatus and a discharging agent of an epoxidation reaction apparatus, specifically, may be one or more of a discharging agent of a cyclohexanone ammoximation reaction apparatus, a discharging agent of a phenol hydroxylation reaction apparatus and a discharging agent of an epoxidation reaction apparatus, and preferably, the discharging agent is a catalyst deactivated by reaction in an alkaline environment, and therefore, for the present invention, it is preferable that the discharging agent of the titanium silicalite molecular sieve is a discharging agent of a cyclohexanone ammoximation reaction apparatus (for example, deactivated titanium silicalite TS-1, powdery molecular sieve having a particle size of 100-500 nm).
In the present invention, the discharging agent is a deactivated catalyst whose activity cannot be restored to 50% of the initial activity by a conventional regeneration method such as solvent washing or calcination (the initial activity is the average activity of the catalyst within 1 hour under the same reaction conditions; for example, in the actual cyclohexanone oximation reaction, the initial activity of the catalyst is generally 95% or more).
The activity of the discharging agent varies depending on its source. Generally, the activity of the discharging agent can be 5-95% of the activity of the titanium silicalite when fresh (i.e., the activity of the fresh agent). Preferably, the activity of the discharging agent can be less than 50% of the activity of the titanium silicalite molecular sieve in a fresh state, and more preferably, the activity of the discharging agent can be 10-40% of the activity of the titanium silicalite molecular sieve in a fresh state. The activity of the titanium silicalite molecular sieve freshener is generally more than 90%, and usually more than 95%.
In the present invention, the discharging agent may be derived from an industrial deactivator or a deactivated catalyst after reaction in a laboratory.
In the invention, the discharging agent of each device is respectively measured by adopting the reaction of each device, and the discharging agent is the discharging agent provided that the activity of the discharging agent is lower than that of a fresh catalyst in the same device under the same reaction condition. As mentioned before, the activity of the discharging agent is preferably less than 50% of the activity of the fresh catalyst.
In the present invention, taking the discharging agent of the cyclohexanone ammoximation reaction device as an example, the activity is measured by the following method:
taking a TS-1 molecular sieve (prepared by the method described in Zeolite, 1992, Vol.12: 943-950), TiO22.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30 wt% hydrogen peroxide (water to hydrogen peroxide volume ratio of 10: 9) a mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1: 2.5) adding 36 wt% ammonia water at the speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at the corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product after the reaction is stable, analyzing the liquid phase composition by using a gas chromatography method every 1 hour, calculating the conversion rate of cyclohexanone by using the following formula, and taking the conversion rate as the activity of the titanium-silicon molecular sieve. Cyclohexanone(ii) conversion rate of [ (molar amount of cyclohexanone charged-molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone charged]X 100%. Wherein the result of 1h is taken as the initial activity.
According to the process of the present invention, the heat treatment is generally carried out under autogenous pressure in the case of sealing, unless otherwise specified.
According to a preferred embodiment of the invention, SiO is used2The molar ratio of the catalyst containing the titanium-silicon molecular sieve to the silicon source is 100: (0.1 to 10), more preferably 100: (0.5-5), most preferably 100: (1-5).
According to the present invention, the silicon source may be an inorganic silicon source and/or an organic silicon source. Specifically, the organic silicon source may be, for example, one or more selected from silicon-containing compounds represented by formula I,
in the formula I, R1、R2、R3And R4Each is C1-C4Alkyl of (2) including C1-C4Straight chain alkyl of (2) and C3-C4Branched alkyl groups of (a), for example: r1、R2、R3And R4Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.
Specifically, the organic silicon source may be one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate, and tetra-n-butyl orthosilicate. Tetraethyl orthosilicate or methyl orthosilicate are used as examples in the specific embodiments of the invention, but do not limit the scope of the invention accordingly.
According to the method of the present invention, the optional range of the types of the inorganic silicon source is wide, and for the present invention, the inorganic silicon source is preferably one or more of silicate, silica sol and silica gel, and the silica gel or silica sol in the present invention may be silica gel or silica sol obtained by various production methods in various forms, and the silicate is sodium silicate, for example.
According to the process of the present invention, preferably the silicon source is selected from at least one of organic silicon sources.
According to a preferred embodiment of the present invention, the hydrolysis rate of the organic silicon source is 40 to 60%. Thus, the catalytic performance of the obtained tin-titanium-silicon molecular sieve can be further improved.
According to a preferred embodiment of the present invention, the temperature of the first heat treatment is preferably 40 to 200 ℃, more preferably 50 to 180 ℃, and still more preferably 60 to 180 ℃.
According to the method of the present invention, the time of the first heat treatment can be determined as required, and for the present invention, the time of the first heat treatment is preferably 0.5 to 360 hours, preferably 1 to 240 hours, and more preferably 2 to 120 hours.
According to the method of the present invention, the temperature of the second heat treatment is preferably 100-.
According to the method of the present invention, the time of the second heat treatment can be determined according to the need, and for the present invention, the time of the second heat treatment is preferably 0.5 to 96 hours, preferably 2 to 48 hours, and more preferably 6 to 24 hours.
According to a preferred embodiment of the present invention, when the silicon source is selected from at least one of organic silicon sources (further preferably, the hydrolysis rate of the organic silicon source is 40 to 60%), it is preferable that the second heat treatment includes: treatment at 100-. The inventor of the present invention finds, through research, that the adoption of the preferred embodiment is more beneficial to improving the catalytic performance of the catalyst.
According to the process of the present invention, the concentration of the acid solution is preferably >0.1mol/L, more preferably ≧ 1mol/L, further preferably 1 to 15 mol/L. In the invention, the main solvent of the acid solution is water, and other solvent auxiliaries can be added according to the requirement. The prepared tin-titanium-silicon molecular sieve has more obvious characteristics such as micropore distribution with the aperture of 1-1.8nm and the like.
According to the process of the invention, catalysts containing titanium silicalite are preferred: tin source: silicon source: acid: alkali source: the molar ratio of water is 100: (0.1-10): (0.1-10): (0.005-50): (0.5-50): (20-1000), further preferred are catalysts comprising titanium silicalite: a tin source: silicon source: acid: alkali source: the molar ratio of water is 100: (0.2-5): (0.5-5): (1-15): (1-20): (100-800) the catalyst containing the titanium silicalite molecular sieve is SiO2The silicon source is SiO2Measured as H, acid+The alkali source is N or OH-More preferably, the mass ratio of the catalyst containing the titanium silicalite molecular sieve to the acid is 100: (2-15).
According to the method of the present invention, the acid may be selected from a wide range of types, and may be an organic acid and/or an inorganic acid, preferably an inorganic acid; wherein, the inorganic acid can be one or more of HCl, sulfuric acid, perchloric acid, nitric acid and phosphoric acid, and is preferably phosphoric acid; the organic acid can be C1-C10 organic carboxylic acid, preferably one or more of formic acid, acetic acid, propionic acid, naphthenic acid, peroxyacetic acid and peroxypropionic acid.
According to the method of the present invention, the variety of the alkali source is wide, and the alkali source can be an organic alkali source and/or an inorganic alkali source, wherein the inorganic alkali source can be ammonia, or alkali whose cation is alkali metal or alkaline earth metal, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, barium hydroxide, etc., and the organic alkali source can be one or more of urea, aliphatic amine compound, aliphatic alcohol amine compound, and quaternary ammonium base compound.
According to a preferred embodiment of the present invention, the alkali source is one or more of ammonia, an aliphatic amine, an aliphatic alcohol amine and a quaternary ammonium base.
In the invention, the quaternary ammonium base can be various organic quaternary ammonium bases, and the aliphatic amine can be various NH3In which at least one hydrogen is substituted with an aliphatic hydrocarbon group (preferably an alkyl group), which may be a variety of NH3Wherein at least one hydrogen is substituted with a hydroxyl-containing aliphatic hydrocarbon group (preferably an alkyl group).
Specifically, the quaternary ammonium base may be a quaternary ammonium base represented by formula II, the aliphatic amine may be an aliphatic amine represented by formula III, and the aliphatic alcohol amine may be an aliphatic alcohol amine represented by formula IV:
Figure BDA0001708568810000111
in the formula II, R5、R6、R7And R8Each is C1-C4Alkyl of (2) including C1-C4Straight chain alkyl of (2) and C3-C4Branched alkyl groups of (a), for example: r5、R6、R7And R8Each may be methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.
R9(NH2)n(formula III)
In the formula III, n is an integer of 1 or 2. When n is 1, R9Is C1～C6Alkyl of (2) including C1～C6Straight chain alkyl of (2) and C3-C6Such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl and n-hexyl. When n is 2, R9Is C1-C6Alkylene of (2) including C1～C6Linear alkylene of (A) and (C)3～C6Such as methylene, ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene. More preferably, the aliphatic amine compound is one or more of ethylamine, n-butylamine, butanediamine and hexamethylenediamine
(HOR10)mNH(3-m)(formula IV)
In the formula IV, m are R10Are the same or different and are each C1-C4Alkylene of (2) including C1-C4Linear alkylene of (A) and (C)3-C4Branched alkylene groups of (a), such as methylene, ethylene, n-propylene and n-butylene; m is 1, 2 or 3. More preferably, the aliphatic alcohol amine compound is one or more of monoethanolamine, diethanolamine and triethanolamine.
According to a preferred embodiment of the present invention, in order to further improve the pore order of the synthesized tin-titanium-silicon molecular sieve, the alkali source is preferably one or more of sodium hydroxide, ammonia water, ethylenediamine, n-butylamine, butanediamine, hexamethylenediamine, monoethanolamine, diethanolamine, triethanolamine, tetraethylammonium hydroxide and tetrapropylammonium hydroxide.
Wherein, when the alkali source contains ammonia water, the mol ratio of the alkali source includes NH in molecular form3And NH in ionic form4 +The presence of ammonia.
In the present invention, the alkali source contains both N and OH-Unless otherwise specified, the alkali source is counted as N.
According to the process of the present invention, preferably the alkali source is provided in the form of an alkali solution, more preferably an alkali solution having a pH > 9.
According to the method of the present invention, the variety of the tin source can be widely selected, and any substance containing tin (for example, a compound containing tin element and/or a simple substance of tin) can achieve the object of the present invention, and in the present invention, the tin source is preferably a compound containing tin element, and may be an inorganic tin compound such as a water-soluble inorganic tin salt, and/or an organic tin compound such as one or more of tin chloride, tin chloride pentahydrate, stannous chloride hydrate, stannous metastannic acid, calcium stannate, potassium stannate, sodium stannate, lithium stannate, magnesium stannate, stannous sulfate, stannous pyrophosphate, and stannic pyrophosphate; the organotin compound may be an organic acid salt of tin and/or other organic compounds containing tin, such as organic acid compounds and stannates, preferably an organic acid salt of tin and/or stannates. The organic acid salt of tin is preferably C2-C10 organic acid salt, including but not limited to one or more of tin acetate, stannous acetate and stannous octoate. The stannate may include various stannates, and tetraethyl stannate, tin chloride pentahydrate, tin acetate, tetrabutyl stannate, and the like are used in the examples of the present invention as examples for illustrative purposes.
In a more preferred embodiment of the invention, the process of mixing the titanium-containing molecular sieve catalyst with the acid solution with the molar concentration of more than 0.1mol/L is carried out under the condition of refluxing the acid solution, and the obtained tin-titanium-containing molecular sieve has more obvious characteristic physicochemical characteristics.
According to the present invention, it is preferred that the method of the present invention further comprises a step of recovering a product from the heat-treated material of step (2), the step of recovering the product being a conventional method familiar to those skilled in the art, and generally means a process of filtering, washing, drying and calcining the product, without particular requirement. Wherein the drying process can be carried out at a temperature between room temperature and 200 ℃, and the roasting process can be carried out at a temperature between 300 ℃ and 800 ℃ in a nitrogen atmosphere for 0.5-6 hours and then in an air atmosphere for 3-12 hours.
The invention provides a tin-titanium-silicon molecular sieve obtained by the preparation method. In the thioether oxidation reaction, the tin-titanium-silicon molecular sieve prepared by the preparation method can effectively adjust the selectivity of a target product.
Therefore, the invention also provides the molecular sieve and the application of the molecular sieve obtained by the preparation method in thioether oxidation reaction. In the thioether oxidation reaction, the molecular sieve obtained by adopting the molecular sieve and the method can effectively modulate the selectivity of a target product.
The invention provides a thioether oxidation method, which comprises the following steps: under the condition of oxidizing thioether, a liquid mixture is contacted with a catalyst, wherein the liquid mixture contains thioether, at least one oxidant and optionally at least one solvent, and the catalyst contains the tin-titanium-silicon molecular sieve or the tin-titanium-silicon molecular sieve prepared by the preparation method.
According to the process of the present invention, the thioether may be any of various compounds having an-S-bond, preferably the thioether is selected from the group consisting of thioethers having 2 to 18 carbon atoms, more preferably dimethyl sulfide or dimethyl sulfide.
According to the method of the present invention, the oxidizing agent may be any of various conventional substances capable of oxidizing a thioether. The method of the invention is particularly suitable for the occasion of oxidizing thioether by taking peroxide as an oxidizing agent, so that the effective utilization rate of the peroxide can be obviously improved. The peroxide is a compound containing an-O-O-bond in the molecular structure, and can be selected from hydrogen peroxide, organic peroxide and peracid. The organic peroxide is a substance obtained by substituting one or two hydrogen atoms in a hydrogen peroxide molecule with an organic group. The peracid refers to an organic oxyacid having an-O-O-bond in the molecular structure. In the present invention, specific examples of the oxidizing agent may include, but are not limited to: hydrogen peroxide, tert-butyl hydroperoxide, cumene peroxide, cyclohexyl hydroperoxide, peracetic acid and propionic acid. Preferably, the oxidizing agent is hydrogen peroxide, which further reduces the separation cost.
The hydrogen peroxide may be hydrogen peroxide in various forms commonly used in the art. From the viewpoint of further improving the safety of the process according to the invention, the process according to the invention preferably uses hydrogen peroxide in the form of an aqueous solution. According to the process of the invention, when the hydrogen peroxide is provided in the form of an aqueous solution, the concentration of the aqueous hydrogen peroxide solution may be a concentration conventional in the art, for example: 20-80 wt%. Aqueous solutions of hydrogen peroxide at concentrations meeting the above requirements may be prepared by conventional methods or may be obtained commercially, for example: can be 30 percent by weight of hydrogen peroxide, 50 percent by weight of hydrogen peroxide or 70 percent by weight of hydrogen peroxide which can be obtained commercially.
The amount of the oxidizing agent to be used may be conventionally selected and is not particularly limited. In general, the molar ratio of thioether to oxidant may be 1: (0.1-10), preferably 1: (0.2-5).
According to the process of the present invention, the liquid mixture may or may not contain a solvent, and preferably contains a solvent, so that the reaction speed can be adjusted by adjusting the content of the solvent in the liquid mixture to make the reaction more stable. The solvent may be a variety of liquid substances that are capable of dissolving the thioether and the oxidizing agent, or facilitating mixing of the two, as well as dissolving the target oxidation product. In general, the solvent may be selected from water, C1-C6Alcohol of (1), C3-C8Ketone and C2-C6A nitrile of (a). Specific examples of the solvent may include, but are not limited to: water, methanol, ethanol, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone and acetonitrile. Preferably, the solvent is selected from water and C1-C6The alcohol of (1). More preferably, the solvent is methanol and/or water.
The amount of the solvent to be used may be appropriately selected depending on the amounts of the thioether and the oxidizing agent to be used. Generally, the molar ratio of the solvent to the thioether may be (0.1-100): 1, preferably (0.2-80): 1.
according to the method of the present invention, the oxidation reaction conditions are dependent on the target oxidation product. Generally, the oxidation reaction can be carried out at a temperature of from 0 to 120 ℃, preferably at a temperature of from 20 to 80 ℃; the pressure in the reactor may be in the range of 0 to 5MPa, preferably 0.1 to 3MPa, in terms of gauge pressure.
The method according to the present invention may further comprise separating the reaction mixture output from the fixed-bed reactor to obtain the target oxidation product as well as unreacted reactants. The method for separating the reaction mixture may be a method conventionally selected in the art, and is not particularly limited. The separated unreacted reactant can be recycled.
The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.
In the following examples and comparative examples, the reagents used were all commercially available analytical grade reagents, and the pressures were measured as gauge pressures.
The discharging agents of the following examples and comparative examples were obtained as follows, and the activity of titanium silicalite molecular sieves (including titanium silicalite discharging agents, and titanium silicalite fresheners) was measured by the following method.
Taking a TS-1 molecular sieve (prepared by the method described in Zeolite, 1992, Vol.12: 943-950), TiO22.1%) was placed in a 100mL slurry bed reactor with continuous feed and membrane separation means, and a mixture of water and 30 wt% hydrogen peroxide (water and peroxide) was added under stirring at a rate of 5.7mL/hThe volume ratio of hydrogen oxide is 10: 9) a mixture of cyclohexanone and tert-butanol was added at a rate of 10.5mL/h (the volume ratio of cyclohexanone to tert-butanol was 1: 2.5) adding 36 wt% ammonia water at the speed of 5.7mL/h, simultaneously adding the three material flows, continuously discharging at the corresponding speed, maintaining the reaction temperature at 80 ℃, sampling the product after the reaction is stable, analyzing the liquid phase composition by using a gas chromatography method every 1 hour, calculating the conversion rate of cyclohexanone by using the following formula, and taking the conversion rate as the activity of the titanium-silicon molecular sieve. Conversion of cyclohexanone [ (molar amount of cyclohexanone charged-molar amount of unreacted cyclohexanone)/molar amount of cyclohexanone charged]×100％。
The cyclohexanone conversion, measured for the first time, i.e. 1h, was its initial activity, which was 99.5%. After a period of about 168 hours, the cyclohexanone conversion rate is reduced from the initial 99.5% to 50%, the catalyst is separated and regenerated by roasting (roasting at 570 ℃ for 4 hours in air atmosphere), and then the catalyst is continuously used in cyclohexanone ammoximation reaction, the step is repeatedly carried out until the activity after regeneration is lower than 50% of the initial activity, at the moment, the inactivated ammoximation catalyst sample is used as the discharging agent of the invention, and the discharging agents SH-1 (the activity is 50%), SH-2 (the activity is 40%), SH-3 (the activity is 25%) and SH-4 (the activity is 10%) are sequentially obtained according to the method.
The pore volume and pore size distribution of the sample were measured on a Micromeritics ASAP2405 static nitrogen adsorption apparatus, and the specific data are shown in Table 1.
The elemental compositions of tin, titanium and silicon of the samples were measured on a 3271E model X-ray fluorescence spectrometer, manufactured by Nippon chemical and mechanical Co., Ltd., and the data are shown in Table 1.
In the present invention, the surface Si/Ti ratio was measured by an ESCALB 250 type X-ray photoelectron spectrometer manufactured by Thermo Scientific, and the bulk Si/Ti ratio was measured by a 3271E type X-ray fluorescence spectrometer manufactured by Nippon chemical industries, Ltd., and the surface Si/Ti ratio/bulk Si/Ti ratio is shown in Table 1.
The Fourier transform infrared absorption spectrum of the sample is measured on a Nicolet 8210 type Fourier infrared spectrometer, KBr tablets are adopted under vacuum (the sample accounts for 1wt percent), and the test range is 400--1。
In the following comparative examples and examples, the contents of the respective components in the obtained reaction solution were analyzed by gas chromatography, and on the basis of which the relative amounts of increase in the conversion of the sulfide and the selectivity of sulfone in the product were calculated by the following formulas, respectively:
thioether conversion ═ (moles of thioether participating in the reaction/moles of thioether added) × 100%;
wherein the moles of thioether involved in the reaction-the moles of thioether remaining in the resulting reaction mixture-are the moles of thioether added;
the relative amount of selectivity increase in sulfone in the product is ═ (moles of sulfone in the reaction mixture from the test example-moles of sulfone in the reaction mixture from the test reference)/moles of sulfone in the reaction mixture from the test reference x 100%.
The invention is referred to comparative example 1.
In the following examples, the amount of hydrolysis of the organic silicon source was measured by gas chromatography. The gas chromatograph used was an Agilent 6890N equipped with thermal conductivity detectors TCD and HP-5 capillary columns (30m 320 μm 25 μm). Wherein the injection port temperature is 180 ℃, the column temperature is 150 ℃, nitrogen is used as carrier gas, and the flow rate of the carrier gas is 25 mL/min. The specific method comprises the following steps: and (3) taking a certain amount of mixture to be injected from an injection port of a gas chromatograph, flowing through a chromatographic column, detecting by using TCD (trichloroacetic acid) and quantifying by using an external standard method. Calculating the hydrolysis rate of the organic silicon source by adopting the following formula:
Xorganic silicon source％＝[(mo Organic silicon source－mOrganic silicon source)/mo Organic silicon source]×100％
In the formula, XOrganic silicon sourceThe hydrolysis rate of the organic silicon source is shown; m iso Organic silicon sourceRepresents the mass of the added organic silicon source; m isOrganic silicon sourceThe mass of the unhydrolyzed organic silicon source is indicated.
Comparative example 1
This comparative example illustrates a conventional process for preparing a titanium silicalite molecular sieve sample that does not contain tin using a silicon ester as a silicon source for hydrothermal crystallization.
Tetraethyl orthosilicate, titanium isopropoxide and tetrapropylammonium hydroxide are mixed, and proper amount of distilled water is added for stirring and mixing, wherein the molar composition in a reaction system is tetraethyl orthosilicate: titanium isopropoxide: tetrapropylammonium hydroxide: 100 parts of water: 5: 10: 200, wherein tetraethyl orthosilicate is SiO2Counting; hydrolyzing at normal pressure and 60 deg.C for 1.0h, stirring at 75 deg.C for 3h, placing the mixed solution in a stainless steel sealed reaction kettle, and standing at 170 deg.C for 3d to obtain crystallized product mixture; filtering the mixture, washing with water, drying at 110 deg.C for 60min to obtain molecular sieve raw powder, and calcining at 550 deg.C for 3 hr to obtain titanium-silicon molecular sieve directly crystallized by hydrothermal method, wherein XRD crystal phase is MFI structure.
Comparative example 2
This comparative example illustrates a conventional process for preparing a sample of a titanium silicalite molecular sieve containing tin by hydrothermal crystallization using a silicon ester as a silicon source.
Tetraethyl orthosilicate, tin chloride pentahydrate serving as a tin source, titanium isopropoxide and tetrapropylammonium hydroxide are mixed, and a proper amount of distilled water is added for stirring and mixing, wherein the molar composition in a reaction system is tetraethyl orthosilicate: titanium isopropoxide: tin source stannic chloride pentahydrate: tetrapropylammonium hydroxide: 100 parts of water: 5: 2: 10: 200, wherein tetraethyl orthosilicate is SiO2Counting; hydrolyzing at normal pressure and 60 deg.C for 1.0h, stirring at 75 deg.C for 3h, placing the mixed solution in a stainless steel sealed reaction kettle, and standing at 170 deg.C for 3d to obtain crystallized product mixture; filtering the mixture, washing with water, drying at 110 deg.C for 60min to obtain molecular sieve raw powder, and calcining at 550 deg.C for 3h to obtain hydrothermally directly crystallized Sn-Ti-Si molecular sieve, wherein the XRD phase diagram of the molecular sieve is identical to that of comparative example 1 and has MFI structure.
Comparative example 3
This comparative example illustrates the process of impregnating a supported tin with the titanium silicalite sample prepared in comparative example 1.
Mixing the titanium silicalite molecular sieve prepared in the comparative example 1 with a tin source stannic chloride pentahydrate aqueous solution, wherein the mass ratio of the titanium silicalite molecular sieve to the tin source stannic chloride pentahydrate to the water is 10:2.6:25, stirring for 6h at the normal pressure and 60 ℃, filtering the mixture, washing with water, drying for 60min at 110 ℃, and roasting for 3h at 550 ℃ to obtain the tin-loaded titanium silicalite molecular sieve, wherein the XRD crystalline phase of the tin-loaded titanium silicalite molecular sieve is of an MFI structure.
Comparative example 4
This comparative example illustrates the process of impregnating a loaded tin with a sample of discharging agent SH-2.
Mixing an unloading agent SH-2 with a tin source stannic chloride pentahydrate aqueous solution, wherein the mass ratio of the unloading agent to the tin source stannic chloride pentahydrate to water is 10:2.1:10, stirring for 12h at normal pressure and 40 ℃, filtering the mixture, washing with water, drying for 60min at 110 ℃, and roasting for 3h at 550 ℃ to obtain the tin-loaded titanium-silicon molecular sieve, wherein the XRD crystalline phase of the titanium-silicon molecular sieve is of an MFI structure.
Example 1
This example illustrates the method and product provided by the present invention.
Mixing and pulping the deactivated cyclohexanone oximation catalyst SH-2 with 1mol/L hydrochloric acid aqueous solution at normal temperature (20 ℃, the same in other comparative examples and examples) and normal pressure (0.1MPa, the same in other comparative examples and examples), and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours; after solid-liquid separation, mixing solid, tin chloride pentahydrate serving as a tin source, tetraethyl orthosilicate serving as an organic silicon source and a sodium hydroxide aqueous solution (pH is 12), transferring the mixture into a stainless steel sealed reaction kettle after tetraethyl orthosilicate is hydrolyzed (the hydrolysis rate of the organic silicon source is 40%), treating for 10 hours at 100 ℃, and then treating for 12 hours at 170 ℃, wherein the deactivated cyclohexanone oximation catalyst is prepared by the following steps: a tin source: an organic silicon source: acid: alkali: the molar ratio of water is 100: 1: 2: 10: 5: 250, deactivated cyclohexanone oximation catalyst and organic silicon source made of SiO2Measured as H, acid+Calculated as OH, base-And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and then roasting at 550 ℃ for 3h to obtain the tin-titanium-silicon molecular sieve S-1.
Example 2
This example illustrates the method and product provided by the present invention.
At normal temperature and normal pressure, firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-3 and 5mol/L hydrochloric acid solution, and then, adding the mixed pulp into 60 partsMixing and stirring at the temperature of 1 ℃ for 1 hour; after solid-liquid separation, mixing solid, tin source tin chloride pentahydrate, organic silicon source methyl orthosilicate and tetrapropyl ammonium hydroxide aqueous solution (pH is 10), transferring the mixture into a stainless steel sealed reaction kettle after the methyl orthosilicate is hydrolyzed (the hydrolysis rate of the organic silicon source is 50%), treating for 4 hours at 130 ℃, and then treating for 20 hours at 150 ℃, wherein the deactivated cyclohexanone oximation catalyst: a tin source: an organic silicon source: acid: alkali: the molar ratio of water is 100: 2: 1: 15: 15: 200 deactivated cyclohexanone oximation catalyst and organic silicon source made of SiO2Measured as H, acid+The base is calculated as N. The product was then recovered according to the procedure of example 1 to obtain the tin titanium silicalite molecular sieve S-2.
Example 3
This example illustrates the method and product provided by the present invention.
Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-4 and 8mol/L nitric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed slurry at 100 ℃ for 2 hours; after solid-liquid separation, mixing solid, tin source tetrabutyl stannate, organic silicon source tetraethyl orthosilicate and sodium hydroxide aqueous solution (pH is 14), transferring the mixture into a stainless steel sealed reaction kettle after tetraethyl orthosilicate is hydrolyzed (the hydrolysis rate of the organic silicon source is 60%), treating for 6 hours at 110 ℃, and then treating for 6 hours at 200 ℃, wherein the deactivated cyclohexanone oximation catalyst: a tin source: an organic silicon source: acid: alkali: the molar ratio of water is 100: 0.5: 5: 10: 15: 600 deactivated cyclohexanone oximation catalyst and organic silicon source made of SiO2Measured as H, acid+Calculated as OH, base-And (6) counting. The product was then recovered according to the procedure of example 1 to obtain the tin titanium silicalite molecular sieve S-3.
Example 4
This example illustrates the method and product provided by the present invention.
Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-1 and 5mol/L sulfuric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed slurry at 120 ℃ for 1 h; after solid-liquid separation, mixing the solid, tin source tetraethyl stannate, organic silicon source tetraethyl orthosilicate and n-butylamine aqueous solution (pH is 12) until tetraethyl orthosilicate is obtainedAnd (3) after hydrolysis (the hydrolysis rate of the organic silicon source is 55 percent), transferring the mixture into a stainless steel sealed reaction kettle, treating the mixture at 120 ℃ for 7 hours, and then treating the mixture at 170 ℃ for 10 hours, wherein the deactivated cyclohexanone oximation catalyst: a tin source: an organic silicon source: acid: alkali: the molar ratio of water is 100: 1.5: 3.5: 2: 2: 100 deactivated cyclohexanone oximation catalyst and organic silicon source made of SiO2Measured as H, acid+The base is calculated as N. The product was then recovered according to the procedure of example 1 to obtain the tin titanium silicalite molecular sieve S-4.
Example 5
This example illustrates the method and product provided by the present invention.
Firstly, mixing and pulping deactivated cyclohexanone oximation catalyst SH-2 and 2mol/L perchloric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed pulp at 70 ℃ for 5 hours; after solid-liquid separation, mixing the solid, tin source tin acetate, organic silicon source tetraethyl orthosilicate and ammonia water (pH is 11), transferring the mixture into a stainless steel sealed reaction kettle after the tetraethyl orthosilicate is hydrolyzed (the hydrolysis rate of the organic silicon source is 45%), treating the mixture at 100 ℃ for 10 hours, and then treating the mixture at 170 ℃ for 12 hours, wherein the deactivated cyclohexanone oximation catalyst: a tin source: an organic silicon source: acid: alkali: the molar ratio of water is 100: 1: 2.5: 5: 20: 100 deactivated cyclohexanone oximation catalyst and organic silicon source made of SiO2Measured as H, acid+The base is calculated as N. The product was then recovered according to the procedure of example 1 to obtain the tin titanium silicalite molecular sieve S-5.
Example 6
This example illustrates the method and product provided by the present invention.
Firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-2 and 15mol/L phosphoric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed slurry at 180 ℃ for 3 hours; after solid-liquid separation, mixing solid, tin chloride pentahydrate serving as a tin source, tetraethyl orthosilicate serving as an organic silicon source and a sodium hydroxide aqueous solution (pH is 14), transferring the mixture into a stainless steel sealed reaction kettle after tetraethyl orthosilicate is hydrolyzed (the hydrolysis rate of the organic silicon source is 40%), treating for 5 hours at 100 ℃, and then treating for 6 hours at 150 ℃, wherein the deactivated cyclohexanone oximation catalyst is prepared by the following steps: a tin source: organic compoundsSilicon source: acid: alkali: the molar ratio of water is 100: 2: 2: 10: 15: 600 deactivated cyclohexanone oximation catalyst and organic silicon source made of SiO2Measured as H, acid+Calculated as OH, base-And (6) counting. The product was then recovered according to the procedure of example 1 to obtain the tin titanium silicalite molecular sieve S-6.
Example 7
This example illustrates the method and product provided by the present invention.
A molecular sieve was prepared according to the method of example 1, except that SiO2The organic silicon source tetraethyl orthosilicate is replaced by an equimolar amount of inorganic silicon source silica gel (purchased from Qingdao silica gel factory, SiO)2Has a mass fraction of more than 95%, an average pore diameter of 2.6nm and a specific surface area of 680m2Per g, pore volume 0.38ml/g), in particular: firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-2 and 1mol/L hydrochloric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours; after solid-liquid separation, mixing the solid, tin source tin chloride pentahydrate, inorganic silicon source silica gel and sodium hydroxide aqueous solution (pH is 12), then transferring the mixture into a stainless steel sealed reaction kettle, treating for 10h at 100 ℃, and then treating for 12h at 170 ℃, wherein the deactivated cyclohexanone oximation catalyst: a tin source: inorganic silicon source: acid: alkali: the molar ratio of water is 100: 1: 2: 10: 5: 250, deactivated cyclohexanone oximation catalyst and inorganic silicon source with SiO2Measured as H, acid+Calculated as OH, base-And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and then roasting at 550 ℃ for 3h to obtain the tin-titanium-silicon molecular sieve S-7.
Example 8
This example illustrates the method and product provided by the present invention.
A molecular sieve was prepared as in example 1, except that the mass composition of the material was SiO2Deactivated cyclohexanone oximation catalyst: the molar ratio of the organic silicon source is 100: 10. obtaining the tin-titanium-silicon molecular sieve S-8.
Example 9
This example illustrates the method and product provided by the present invention.
The molecular sieve was prepared according to the method of example 1, except that after tetraethyl orthosilicate was hydrolyzed (the hydrolysis rate of the organic silicon source was 20%), the mixture was transferred to a stainless steel sealed reaction vessel to obtain the tin-titanium-silicon molecular sieve S-9.
Example 10
This example illustrates the method and product provided by the present invention.
The molecular sieve was prepared according to the method of example 1, except that after tetraethyl orthosilicate was hydrolyzed (the hydrolysis rate of the organic silicon source was 90%), the mixture was transferred to a stainless steel sealed reaction vessel to obtain the tin-titanium-silicon molecular sieve S-10.
Example 11
This example illustrates the method and product provided by the present invention.
A molecular sieve was prepared according to the method of example 1, except that after tetraethyl orthosilicate was hydrolyzed (the hydrolysis rate of the organic silicon source was 40%), the mixture was transferred to a stainless steel sealed reaction vessel and then treated at 170 ℃ for 22 hours. Obtaining the tin-titanium-silicon molecular sieve S-11.
Example 12
This example illustrates the method and product provided by the present invention.
A molecular sieve was prepared according to the method of example 1, except that after tetraethyl orthosilicate was hydrolyzed (the hydrolysis rate of the organic silicon source was 40%), the mixture was transferred to a stainless steel sealed reaction vessel and then treated at 140 ℃ for 22 hours. Obtaining the tin-titanium-silicon molecular sieve S-12.
Comparative example 5
In the preparation process of the molecular sieve, no organic silicon source is added, and specifically: firstly, mixing and pulping the inactivated cyclohexanone oximation catalyst SH-2 and 1mol/L hydrochloric acid aqueous solution at normal temperature and normal pressure, and then mixing and stirring the mixed pulp at 80 ℃ for 12 hours; after solid-liquid separation, mixing the solid, tin source stannic chloride pentahydrate and sodium hydroxide aqueous solution (pH is 12), then transferring the mixture into a stainless steel sealed reaction kettle, and treating for 12h at 170 ℃, wherein the deactivated cyclohexanone oximation catalyst: a tin source: acid: alkali: the molar ratio of water is 100: 1: 10: 5: 250, deactivated cyclohexanone oximation catalyst with SiO2Measured as H, acid+Metering alkaliWith OH-And (6) counting. And filtering the obtained product, washing with water, drying at 110 ℃ for 120min, and then roasting at 550 ℃ for 3h to obtain the tin-titanium-silicon molecular sieve D-5.
Comparative example 6
According to the method of comparative example 5, except that tin chloride pentahydrate, a tin source, was not added during the preparation of the molecular sieve, titanium silicalite D-6 was obtained.
TABLE 1
Figure BDA0001708568810000231
In table 1:
a is nSn/nTi, nSn is the molar weight of the tin element in the molecular sieve, and nTi is the molar weight of the titanium element in the molecular sieve;
B＝I960/I800，I960the infrared absorption spectrum of the molecular sieve is 960cm-1Absorption intensity in the vicinity, I800The infrared absorption spectrum of the molecular sieve is 800cm-1Absorption strength in the vicinity;
C＝X1-1.8/X0.4-0.9，X0.4-0.9the ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X1-1.8The proportion of the micropore diameter of the molecular sieve in the range of 1-1.8nm to the total micropore diameter distribution amount is adopted;
D＝Tw/Tk，Twis the micropore volume of the molecular sieve, TkIs the total pore volume of the molecular sieve;
silicon: titanium: tin refers to the element silicon: titanium element: molar ratio of tin element.
As can be seen from the results of table 1: the tin-titanium-silicon molecular sieve prepared by the preferred method of the invention has the following pore size distribution, the proportion of the pore volume of micropores in the total pore volume, and the silicon element: titanium element: the molar ratio of tin element, the ratio of surface silicon-titanium ratio to bulk silicon-titanium ratio and other data completely satisfy all the characteristics of the product of the invention. In contrast, in the titanium silicalite molecular sieve which is prepared by using silicate as a silicon source and does not contain tin in comparative example 1, the titanium silicalite molecular sieve which is prepared by using silicate as a silicon source and contains tin in comparative example 2, the titanium silicalite molecular sieve which is prepared by using titanium silicalite molecular sieve prepared in comparative example 1 and contains tin in comparative example 3, the tin-containing titanium silicalite molecular sieve material which is prepared by using titanium silicalite molecular sieve prepared in comparative example 4 and contains tin in comparative example 5, the tin-titanium silicalite molecular sieve material which is prepared by using discharging agent to load tin after acid treatment, and the titanium silicalite molecular sieve which is prepared by using discharging agent in comparative example 6 and contains tin after acid treatment and alkali treatment, the pore size distribution and the proportion of the micropore pore volume to the total: titanium element: the molar ratio of tin and other data do not satisfy all the characteristics of the product of the present invention.
Test examples
The catalyst (the molecular sieve prepared in the example and the comparative example is pressed into tablets, the particle size is 10-20 meshes) is filled in a fixed bed reactor to form a catalyst bed layer, and the height-diameter ratio of the catalyst bed layer is 10.
Dimethyl sulfide, hydrogen peroxide (provided as 30 wt.% hydrogen peroxide) as an oxidant and methanol as a solvent were mixed to form a liquid mixture, which was fed from the bottom of the fixed bed reactor and passed through the catalyst bed. Wherein the molar ratio of dimethyl sulfide to hydrogen peroxide is 1: 1.1, the molar ratio of dimethyl sulfide to methanol is 1: 5, the weight hourly space velocity of dimethyl sulfide is 2.5h-1The reaction temperature is 38 ℃, water is used as a heat exchange medium to exchange heat with a catalyst bed layer in the reaction process so as to remove reaction heat, and the pressure in the fixed bed reactor is controlled to be 1.8MPa in the reaction process.
The composition of the reaction mixture output from the reactor during the continuous reaction was monitored and the relative amounts of increase in thioether conversion and sulfone selectivity in the product were calculated, and the results obtained at 0.5 hour of reaction are listed in table 2. In addition, the molecular sieves obtained in example 1, example 7, example 9 and example 10 were tested for their stability and the results obtained after 100 hours of reaction are shown in Table 2.
TABLE 2
Figure BDA0001708568810000251
As can be seen from the data in Table 2, the tin-titanium-silicon molecular sieve with a special physicochemical characteristic structure is used for the reaction of thioether oxidation, is favorable for adjusting the selectivity of a target product (sulfone), has good stability and can obtain good catalytic effect.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims (14)

1. A tin-titanium-silicon molecular sieve, comprising: tin element, titanium element, silicon element and oxygen element, wherein the molecular sieve satisfies X1-1.8/X0.4-0.9＝C，0.3<C<0.85, preferably 0.35<C<0.7，X0.4-0.9The ratio of the pore diameter of the micropores of the molecular sieve in the range of 0.4-0.9nm to the distribution quantity of the total pore diameter, X1-1.8Is the proportion of the pore diameter of the micropores of the molecular sieve in the range of 1-1.8nm in the distribution quantity of the pore diameter of the total micropores.
2. The molecular sieve of claim 1, wherein the molecular sieve satisfies nSn/nTi ═ A, I960/I800B ═ i (a +1) nTi, where 0.1<A<10，0.2<B<1，0<I, nSn is the molar weight of tin element in the molecular sieve, nTi is the molar weight of titanium element in the molecular sieve, I960The infrared absorption spectrum of the molecular sieve is 960cm-1Absorption intensity in the vicinity, I800The infrared absorption spectrum of the molecular sieve is 800cm-1Absorption intensity in the vicinity, preferably, 0.2<A<3，0.3<B<0.7。
3. The molecular sieve of claim 1 or 2, wherein the molecular sieve satisfies Tw/Tk＝D，0.2<D<0.6，TwIs the micropore volume of the molecular sieve, TkIs the total pore volume of the molecular sieve, preferably, 0.2<D<0.45。
4. The molecular sieve according to any one of claims 1 to 3, wherein,
silicon element of the molecular sieve: titanium element: the molar ratio of tin elements is 100: (0.1-10): (0.01-5), preferably 100: (0.2-5): (0.1-3.5).
5. The molecular sieve of any one of claims 1 to 4, wherein the molecular sieve has a surface silicon to titanium ratio of not less than a bulk silicon to titanium ratio, the silicon to titanium ratio being the molar ratio of silicon oxide to titanium oxide;
preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 1.2-5;
further preferably, the ratio of the surface silicon-titanium ratio to the bulk silicon-titanium ratio is 2-4.5.
6. A method of making a tin-titanium-silicon molecular sieve, the method comprising:
(1) mixing a catalyst containing a titanium silicalite molecular sieve with an acid solution to obtain a mixture A, carrying out first heat treatment on the mixture A under a closed condition, and separating to obtain a first solid;
(2) and mixing the first solid, a tin source, a silicon source, an alkali source and water to obtain a mixture B, and carrying out second heat treatment on the mixture B under a closed condition.
7. The preparation method according to claim 6, wherein the silicon source is selected from at least one of organic silicon sources;
preferably, the organic silicon source is one or more selected from silicon-containing compounds shown in formula I;
Figure FDA0001708568800000021
in the formula I, R1、R2、R3And R4Each is C1-C4Alkyl group of (1).
8. The method according to claim 7, wherein the hydrolysis ratio of the organic silicon source in the mixture B is 40 to 60%.
9. The production method according to any one of claims 6 to 8,
the temperature of the first heat treatment is 40-200 ℃; the temperature of the second heat treatment is 100-200 ℃; and/or
The time of the first heat treatment is 0.5-360 h; the time of the second heat treatment is 0.5-96 h.
10. The production method according to claim 7 or 8, wherein the second heat treatment includes:
the treatment is carried out at 100-130 ℃ for 4-20h and then at 150-200 ℃ for 6-40 h.
11. The production method according to claim 6, wherein the concentration of the acid solution>0.1 mol/L; catalyst containing titanium silicalite: a tin source: silicon source: acid: alkali source: the molar ratio of water is 100: (0.1-10): (0.1-10): (0.005-50): (0.5-50): (20-1000) in which the catalyst containing titanium-silicon molecular sieve is SiO2The silicon source is SiO2Measured as H, acid+The alkali source is N or OH-Counting;
preferably in SiO2Meter comprisingThe molar ratio of the catalyst with the titanium-silicon molecular sieve to the silicon source is 100: (0.5-5);
preferably, the acid is an organic acid and/or an inorganic acid; the alkali source is one or more of ammonia, aliphatic amine, aliphatic alcohol amine and quaternary ammonium hydroxide;
preferably, the catalyst containing the titanium silicalite molecular sieve is a discharging agent of an ammoximation reaction device.
12. The tin-titanium-silicon molecular sieve prepared by the preparation method of any one of claims 6 to 11.
13. Use of a tin titanium silicalite molecular sieve as claimed in any one of claims 1 to 5, 12 in a thioether oxidation reaction.
14. A method of oxidizing a thioether, the method comprising: contacting a liquid mixture comprising a thioether, at least one oxidant and optionally at least one solvent with a catalyst under thioether oxidation conditions, wherein the catalyst comprises a tin-titanium-silicon molecular sieve as claimed in any one of claims 1 to 5 or 12;
preferably, the thioether is dimethyl sulfide and/or dimethyl sulfide, the oxidant is peroxide, and the molar ratio of the thioether to the oxidant is 1: (0.1-10); the thioether oxidation conditions include: the temperature is 0-120 ℃, and the pressure is 0-5MPa in gauge pressure.
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