CN111072528A

CN111072528A - Method for preparing sulfoxide

Info

Publication number: CN111072528A
Application number: CN201811214644.5A
Authority: CN
Inventors: 史春风; 林民; 朱斌
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-10-18
Filing date: 2018-10-18
Publication date: 2020-04-28
Anticipated expiration: 2038-10-18
Also published as: CN111072528B

Abstract

The invention discloses a method for preparing sulfoxide, which comprises the step of contacting thioether, at least one oxidant and at least one solvent with a titanium silicalite molecular sieve in a catalytic distillation reactor with at least one reaction section to obtain a material flow containing sulfoxide and a material flow containing unreacted thioether in the reaction section, wherein the catalytic distillation reactor is also filled with alkaline ion exchange resin, the alkaline ion exchange resin is filled in an alkaline reaction zone and/or a tower kettle of the catalytic distillation reactor, and the alkaline reaction zone is positioned at the middle lower part of the reaction section. The method for preparing sulfoxide can effectively reduce the content of impurities in the separated material flow containing unreacted thioether, thereby effectively inhibiting the accumulation tendency of the impurities in the system and simultaneously obtaining higher selectivity of sulfoxide.

Description

Method for preparing sulfoxide

Technical Field

The present invention relates to a process for preparing sulfoxides.

Background

As a typical representative of sulfoxide substances, dimethyl sulfoxide (DMSO) is a sulfur-containing organic compound, is a colorless transparent liquid at room temperature, and has characteristics of high polarity, high hygroscopicity, flammability, high boiling point aprotic property, and the like. Dimethyl sulfoxide is soluble in water, ethanol, acetone, diethyl ether and chloroform, is an inert solvent with strong polarity, and is widely used as a solvent and a reaction reagent. Moreover, dimethyl sulfoxide has high selective extraction capacity and can be used as an extraction solvent for separating alkane from aromatic hydrocarbon, such as: dimethyl sulfoxide can be used for extracting aromatic hydrocarbon or butadiene, and can be used as a processing solvent and a spinning solvent in acrylonitrile polymerization reaction, as a synthetic solvent and a spinning solvent for polyurethane, and as a synthetic solvent for polyamide, chlorofluoroaniline, polyimide and polysulfone. Meanwhile, in the pharmaceutical industry, dimethyl sulfoxide can be directly used as a raw material and a carrier of certain medicines, and also has the effects of diminishing inflammation, relieving pain, promoting urination, tranquilizing and the like, so that dimethyl sulfoxide is often used as an active component of an analgesic medicine to be added into the medicines. In addition, dimethyl sulfoxide can also be used as a capacitance medium, an antifreeze, brake oil, a rare metal extractant and the like.

At present, dimethyl sulfoxide is generally prepared by a dimethyl sulfide oxidation method, and the following production processes are generally adopted.

1. Methanol carbon disulfide method: methanol and carbon disulfide are taken as raw materials, and gamma-Al is taken₂O₃As a catalyst, dimethyl sulfide is firstly synthesized and then is oxidized by nitrogen dioxide (or nitric acid) to obtain dimethyl sulfoxide.

2. Nitrogen dioxide method: methanol and hydrogen sulfide are used as raw materials, and dimethyl sulfide is generated under the action of gamma-alumina; reacting sulfuric acid with sodium nitrite to prepare nitrogen dioxide; the generated dimethyl sulfide and nitrogen dioxide are subjected to oxidation reaction at 60-80 ℃ to generate crude dimethyl sulfoxide, and the crude dimethyl sulfoxide is also generated by directly oxidizing with oxygen; and distilling the crude dimethyl sulfoxide under reduced pressure to obtain refined dimethyl sulfoxide.

3. Dimethyl sulfate method: reacting dimethyl sulfate with sodium sulfide to prepare dimethyl sulfide; reacting sulfuric acid with sodium nitrite to generate nitrogen dioxide; and (3) carrying out oxidation reaction on the dimethyl sulfide and nitrogen dioxide to obtain crude dimethyl sulfoxide, and carrying out neutralization treatment and distillation to obtain refined dimethyl sulfoxide.

In addition, dimethyl sulfoxide can also be produced from dimethyl sulfide by anodic oxidation.

Disclosure of Invention

The catalytic distillation technology is a new chemical engineering method developed in recent years, and the method integrates a catalytic reaction process and a distillation separation process and simultaneously performs reaction and separation in one reactor. The inventor of the present invention applies the catalytic distillation technology to the reaction of oxidizing thioether to prepare sulfoxide, and finds that when thioether is in excess relative to an oxidant and a solvent containing methanol is used in a catalytic distillation reactor and a titanium silicalite molecular sieve is used as a catalyst to perform an oxidation reaction to prepare a corresponding sulfoxide substance, the content of impurities (the impurities refer to the substances with a boiling point higher than 0 ℃ at normal pressure in the unreacted thioether stream) in the separated unreacted thioether is still high. Because the unreacted thioether is generally treated in a recycling manner, impurities in a reaction system are inevitably accumulated, so that the content of the impurities in the system is continuously increased, and the recycled impurities are subjected to multiple heating processes, so that a substance with a large molecular weight is formed, the purity of the prepared sulfoxide substance is adversely affected, the impurities (particularly the impurities with the large molecular weight) tend to be deposited on the surface of a titanium silicalite molecular sieve serving as a catalyst, and the impurities cover the active center of the titanium silicalite molecular sieve, so that the activity of the titanium silicalite molecular sieve is reduced.

The inventors of the present invention have conducted intensive studies in view of the above problems and found that: when a catalytic distillation reactor is adopted and a solvent containing methanol is adopted to contact and react thioether and an oxidant with a titanium silicalite molecular sieve to prepare corresponding sulfoxide substances, if alkaline ion exchange resin is filled at the middle lower part of a reaction section of the catalytic distillation reactor and/or in a tower kettle of the catalytic distillation reactor, the impurity content in the separated unreacted thioether can be effectively reduced. The present invention has been completed based on the above findings.

The invention provides a method for preparing sulfoxide, which comprises the step of contacting thioether, at least one oxidant and at least one solvent with a catalyst in a catalytic distillation reactor with at least one reaction section to obtain a material flow containing sulfoxide and a material flow containing unreacted thioether in the reaction section, wherein the solvent contains methanol, the catalyst contains a titanium silicalite molecular sieve, the catalytic distillation reactor is also filled with a basic ion exchange resin, the basic ion exchange resin is filled in a basic reaction zone and/or a tower kettle of the catalytic distillation reactor, the basic reaction zone is positioned in the reaction section, and the theoretical plate number of the position of the upper end of the basic reaction zone is t_ar ^uThe theoretical plate number of the position of the lower end of the alkaline reaction zone is t_ar ^bThe number of theoretical plates at which the top of the reaction section is located is T_r ^uThe theoretical plate number of the position where the bottom of the reaction section is positioned is T_r ^bThe theoretical plate number of the reaction section is T_r，t_ar ^uNot less than T_r ^u+0.5T_r，t_ar ^b/T_r ^b≤1。

According to the method for preparing the sulfoxide, the titanium silicalite molecular sieve is filled in the reaction section of the catalytic distillation reactor, and meanwhile, the alkaline ion exchange resin is filled in the middle lower part of the reaction section of the catalytic distillation reactor and/or the tower kettle of the catalytic distillation reactor, so that the content of impurities in the separated material flow containing the unreacted thioether can be effectively reduced under the synergistic effect of the titanium silicalite molecular sieve and the alkaline ion exchange resin, the accumulation tendency of the impurities in the system is effectively inhibited, and meanwhile, higher sulfoxide selectivity can be obtained.

Drawings

Fig. 1 is a preferred embodiment of the method for preparing sulfoxides according to the invention.

Description of the reference numerals

1: an oxidant storage tank 2: thioether storage tank

3: and (4) a solvent storage tank: light component separation intermediate tank

5: solvent separation tank 6: byproduct separating tank

7: light component stream 8: thioether feed stream

9: gaseous thioether stream 10: heavy ends stream

11: catalytic distillation reactor 12: heavy component separation intermediate tank

13: sulfoxide initial product tank

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the present invention, the term "optionally" means containing or not, including or not, and the term "at least one" means one or two or more.

According to the method for producing a sulfoxide of the present invention, the reaction section is packed with a catalyst having at least one titanium silicalite as an active component. Titanium silicalite is a generic term for a class of zeolites in which a portion of the silicon atoms in the lattice framework are replaced by titanium atoms, and can be represented by the formula xTiO₂·SiO₂And (4) showing. The content of titanium atoms in the titanium silicalite molecular sieve is not particularly limited in the invention, and can be selected conventionally in the field. Specifically, x may be 0.0001 to 0.05, preferably 0.01 to 0.03.

The titanium silicalite molecular sieve can be common titanium silicalite molecular sieves with various topologies, such as: the titanium silicalite molecular sieve can be one or more than two selected from a titanium silicalite molecular sieve with an MFI structure (such as TS-1), a titanium silicalite molecular sieve with an MEL structure (such as TS-2), a titanium silicalite molecular sieve with a BEA structure (such as Ti-Beta), a titanium silicalite molecular sieve with an MWW structure (such as Ti-MCM-22), a titanium silicalite molecular sieve with a hexagonal structure (such as Ti-MCM-41 and Ti-SBA-15), a titanium silicalite molecular sieve with an MOR structure (such as Ti-MOR), a titanium silicalite molecular sieve with a TUN structure (such as Ti-TUN) and a titanium silicalite molecular sieve with other structures (such as Ti-ZSM-48).

Preferably, the titanium silicalite molecular sieve is one or more than two selected from a titanium silicalite molecular sieve with an MFI structure, a titanium silicalite molecular sieve with an MEL structure, a titanium silicalite molecular sieve with a BEA structure and a titanium silicalite molecular sieve with a hexagonal structure. More preferably, the titanium silicalite molecular sieve is a titanium silicalite molecular sieve of MFI structure, such as titanium silicalite molecular sieve TS-1 and/or hollow titanium silicalite molecular sieve. The hollow titanium silicalite molecular sieve is a titanium silicalite molecular sieve with an MFI structure, crystal grains of the titanium silicalite molecular sieve are of a hollow structure, the radial length of a cavity part of the hollow structure is 5-300 nanometers, and the titanium silicalite molecular sieve has the P/P ratio at 25 DEG C₀An amount of adsorbed benzene of at least 70 mg as measured under the conditions of 0.10 and an adsorption time of 1 hourAnd in the gram, a hysteresis loop exists between the adsorption isotherm and the desorption isotherm of the low-temperature nitrogen adsorption of the titanium-silicon molecular sieve. The hollow titanium silicalite molecular sieves are commercially available (e.g., molecular sieves sold under the designation HTS, commercially available from the shogaku corporation, han, south of the lake) and can also be prepared according to the method disclosed in CN 1132699C.

According to the method for preparing the sulfoxide, when the template is adopted in the preparation process of the titanium silicalite molecular sieve, the titanium silicalite molecular sieve can be a titanium silicalite molecular sieve subjected to a process (such as a roasting process) for removing the template, can also be a titanium silicalite molecular sieve which is not subjected to a process (such as a roasting process) for removing the template, and can also be a mixture of the titanium silicalite molecular sieve and the titanium silicalite molecular sieve.

According to the method for preparing sulfoxide, the titanium-silicon molecular sieve can be raw powder of the titanium-silicon molecular sieve or formed titanium-silicon molecular sieve. The formed titanium silicalite molecular sieve contains a carrier (namely, a binder) and the titanium silicalite molecular sieve, wherein the content of the carrier is based on the fact that the titanium silicalite molecular sieve can be bonded together to form a formed body with certain strength. Generally, the content of the titanium silicalite molecular sieve may be 5 to 95 wt% and the content of the carrier may be 5 to 95 wt% based on the total amount of the shaped titanium silicalite molecular sieve. The support for the shaped titanium silicalite molecular sieve may be of conventional choice, such as alumina and/or silica.

The catalysts are commercially available or can be prepared by conventional methods. In a preferred embodiment, the catalyst is prepared by a process comprising the steps of:

(1) under the condition of hydrolytic condensation reaction, contacting an aqueous solution containing a template agent with a mixture containing a titanium source and an organic silicon source to obtain a hydrolytic condensation mixture, and leading out and condensing generated steam in the contact process to obtain condensate;

(2) mixing the hydrolytic condensation mixture with at least part of the condensate, and then carrying out hydrothermal crystallization to obtain a hydrothermal crystallization mixture;

(3) adding a supplementary titanium silicalite molecular sieve into the hydrothermal crystallization mixture, and carrying out spray forming on the obtained slurry.

According to the preferred embodiment, the decomposition of the template agent in the hydrothermal crystallization process can be effectively inhibited, the consumption of the template agent is reduced, the manufacturing cost of the molecular sieve is reduced, the amount of oily substances attached to the inner surface of the hydrothermal crystallization kettle can be avoided or reduced, and the difficulty in cleaning the hydrothermal crystallization kettle is reduced. More importantly, the proportion of the template agent which can be recycled after crystallization is higher, which is more beneficial to reducing the production cost of the titanium-silicon molecular sieve.

In the step (1), the organic silicon source may be any of various materials capable of forming silica under hydrolytic condensation conditions, and 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 group of (1). Said C is₁-C₄Alkyl of (2) includes C₁-C₄Straight chain alkyl of (2) and C₃-C₄Specific examples thereof may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

Preferably, the silicon source is one or more than two selected from methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, isopropyl orthosilicate and n-butyl orthosilicate.

In the step (1), the titanium source may be a titanium source commonly used in the technical field of molecular sieve preparation. In particular, the titanium source may be an organic titanium source (e.g. an organic titanate) and/or an inorganic titanium source (e.g. an inorganic titanium salt). The inorganic titanium source may be TiCl₄、Ti(SO₄)₂、TiOCl₂One or more of titanium hydroxide, titanium oxide, titanium nitrate and titanium phosphate. The organic titanium source can be one or more than two of fatty titanium alkoxide and organic titanate. The titanium source is preferably an organic titanium source, more preferably an organic titanate, and still more preferably of the formula M₄TiO₄The organic titanate shown, wherein 4M can be same or different, and each is preferably C₁-C₄Alkyl group of (1). The titanium source is particularly preferably one or two or more of tetraisopropyl titanate, tetra-n-propyl titanate, tetrabutyl titanate, and tetraethyl titanate.

In the step (1), the template may be a template commonly used in the technical field of molecular sieve preparation, and specifically may be one or more than two of urea, amine, alcohol amine and quaternary ammonium base.

The quaternary ammonium base may be various organic quaternary ammonium bases, the amine may be an organic compound having at least one amino group in a molecular structure, and the alcohol amine may be an organic compound having at least one amino group and at least one hydroxyl group in a molecular structure.

Specifically, the quaternary ammonium base can be a quaternary ammonium base shown in a formula II,

in the formula II, R₅、R₆、R₇And R₈Are the same or different and are each 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.

The amine may be an aliphatic amine of formula III,

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 or 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.

The alcohol amine may be an aliphatic alcohol amine represented by formula IV,

(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-C₄A branched alkylene group of (a), such as methylene, ethylene, n-propylene or n-butylene; m is 1, 2 or 3. Preferably, the alcohol amine is one or more than two of monoethanolamine, diethanolamine and triethanolamine.

Specific examples of the templating agent may include, but are not limited to, one or more of urea, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, ethylamine, n-butylamine, butanediamine, hexamethylenediamine, monoethanolamine, diethanolamine, and triethanolamine.

Preferably, the templating agent is a quaternary ammonium base, more preferably tetraethylammonium hydroxide and/or tetrapropylammonium hydroxide.

In the step (1), the amounts of the organic silicon source, the titanium source, the template agent and the water can be selected conventionally. Generally, the molar ratio of the organic silicon source, the titanium source, the templating agent, and the water may be 100: (0.005-10): (0.005-40): (200-10000), preferably 100: (0.05-8): (0.5-30): (500- & ltSUB & gt 5000- & gt), more preferably 100: (0.2-6): (5-25): (800-4000), more preferably 100: (1-5): (10-20): (1500-3000), the organic silicon source is SiO₂The titanium source is calculated as TiO₂In terms of NH, the template agent₃And (6) counting.

In the step (1), the aqueous solution containing the template is contacted with a mixture containing a titanium source and an organic silicon source, wherein the mixture containing the titanium source and the organic silicon source can be obtained by mixing the titanium source and the organic silicon source. Preferably, the mixture containing the titanium source and the organic silicon source can be obtained by a method comprising the following steps: the titanium source and the organic silicon source are mixed with stirring at 0 to 60 ℃, preferably 15 to 40 ℃, more preferably 20 to 30 ℃ for 1 to 2 hours.

The aqueous solution containing the templating agent may be obtained by dispersing the templating agent in water, the mixing may be carried out at a temperature of 15-60 deg.C, preferably 20-40 deg.C, more preferably 20-30 deg.C, the mixing may be continued for 1-2 hours, and the templating agent may be provided in pure form or in the form of a concentrated solution.

In the step (1), the degree of the contact is preferably such that the hydrolysis rate of the organic silicon source is 85 to 100%, more preferably such that the hydrolysis rate of the organic silicon source is 90 to 100%, even more preferably such that the hydrolysis rate of the organic silicon source is 93 to 100%, and even more preferably such that the hydrolysis rate of the organic silicon source is 95 to 99%. In the present invention, the hydrolysis ratio of the organic silicon source refers to the mass percentage of the silicon-containing compound in the organic silicon source, which is subjected to hydrolysis reaction. The desired hydrolysis rate of the organic silicon source may be obtained by controlling the temperature and/or duration of the contact reaction. Preferably, in step (1), the contacting is carried out at a temperature of 80-98 ℃. More preferably, in step (1), the contacting is carried out at a temperature of from 85 to 95 ℃ (e.g., 89 to 95 ℃). The duration of the contact may be 4 to 36 hours, preferably 6 to 28 hours, more preferably 10 to 24 hours, and still more preferably 12 to 16 hours, provided that the desired hydrolysis rate is obtained. The contacting may be carried out at a pressure of from-0.2 MPa to 0MPa, said pressure being a gauge pressure.

In the step (1), in the process of contacting the aqueous solution containing the template agent with the mixture containing the titanium source and the organic silicon source, the titanium source and the organic silicon source are subjected to a hydrolysis condensation reaction, and a small molecular compound, usually alcohol, is released. These small molecule compounds volatilize to form vapor which escapes from the reaction system. According to this preferred embodiment, the escaping vapour is condensed and the condensate is collected.

The condensate contains water and alcohol. In general, the alcohol may be present in an amount of 80 to 96% by weight, preferably 83 to 95% by weight, more preferably 88 to 92% by weight, and the water may be present in an amount of 4 to 20% by weight, preferably 5 to 17% by weight, more preferably 8 to 12% by weight, based on the total amount of the condensate. In addition to water and alcohol, the condensate also contains nitrogen, which is typically derived from the templating agent. The concentration of nitrogen element in the condensate may be 0.01 to 50mmol/L, preferably 0.02 to 20mmol/L, more preferably 0.04 to 5mmol/L, and still more preferably 0.05 to 3 mmol/L. Particularly preferably, the concentration of nitrogen element in the condensate is 0.5-1.5mmol/L, so that the decomposition of the template agent in the hydrothermal crystallization process can be better inhibited.

In step (2), the entire condensate may be mixed with the hydrolytic condensation mixture, or a portion of the condensate may be mixed with the hydrolytic condensation mixture. Preferably, the condensate may be used in an amount of 1 to 50 parts by weight, preferably 1.5 to 40 parts by weight, relative to 100 parts by weight of the hydrolytic condensation mixture. More preferably, the condensate is used in an amount of 2 to 30 parts by weight with respect to 100 parts by weight of the hydrolytic condensation mixture. Further preferably, the condensate is used in an amount of 10 to 25 parts by weight with respect to 100 parts by weight of the hydrolytic condensation mixture, so that the decomposition of the template agent during hydrothermal crystallization can be inhibited and the quality of the molecular sieve obtained by hydrothermal crystallization can be further improved.

In step (2), the hydrolytic condensation mixture may be mixed with a portion of the condensate at a temperature of 20 to 80 ℃, preferably 40 to 60 ℃ for 1 to 6 hours, preferably 1 to 3 hours. The mixing may be carried out by means of stirring.

In the step (2), the hydrothermal crystallization may be performed under conventional conditions. According to the method for preparing sulfoxide of the invention, the titanium silicalite molecular sieve with expected crystal form can be obtained even if hydrothermal crystallization is carried out at lower temperature for shorter time under the same conditions compared with the existing hydrothermal crystallization conditions. In the step (2), the hydrothermal crystallization is preferably carried out at a temperature of 120-. The duration of the hydrothermal crystallization is preferably 6 to 48 hours, more preferably 8 to 36 hours, and further preferably 10 to 24 hours. The hydrothermal crystallization is usually carried out under autogenous pressure, and pressure may be additionally applied during the hydrothermal crystallization. Preferably, the hydrothermal crystallization is performed under autogenous pressure. The hydrothermal crystallization can be carried out in a conventional hydrothermal crystallization kettle.

In the step (3), the added complementary titanium silicalite molecular sieve can be a titanium silicalite molecular sieve with a topology structure consistent with that of the titanium silicalite molecular sieve prepared in the step (1) and the step (2), or a titanium silicalite molecular sieve with a topology structure different from that of the titanium silicalite molecular sieve prepared in the step (1) and the step (2). According to the method for preparing sulfoxide of the present invention, in a preferred embodiment, the topology of the titanium silicalite prepared by step (1) and step (2) is identical to that of the complementary titanium silicalite, and more preferably, the topology of the titanium silicalite prepared by step (1) and step (2) is the same as that of the complementary titanium silicalite, such as titanium silicalite TS-1.

In the step (3), the weight ratio of the supplementary titanium silicalite molecular sieve to the hydrothermal crystallization mixture is preferably 0.01-10: 1, more preferably 0.05 to 8: 1. further preferably, the weight ratio of the supplementary titanium silicalite molecular sieve to the hydrothermal crystallization mixture is 0.2-5: 1. still more preferably, the weight ratio of the supplementary titanium silicalite molecular sieve to the hydrothermal crystallization mixture is 0.4-3: 1. the hydrothermal crystallization mixture is on a dry basis. In the present invention, the dry basis means the mass of the hydrothermal crystallization mixture after drying at 120 ℃ for 8 hours.

In the step (3), the hydrothermal crystallization mixture and the complementary titanium silicalite molecular sieve can be uniformly mixed by adopting a conventional method. For example, the hydrothermal crystallization mixture and the complementary titanium silicalite molecular sieve can be uniformly mixed by stirring.

In the step (3), the conditions for mixing the hydrothermal crystallization mixture and the complementary titanium silicalite molecular sieve are not particularly limited, and may be performed under conventional conditions. For example, the hydrothermal crystallization mixture may be mixed with the complementary titanium silicalite molecular sieves uniformly at a temperature of 20 to 100 ℃, preferably 30 to 60 ℃, more preferably 30 to 40 ℃. The mixing duration is based on the capability of uniformly mixing the hydrothermal crystallization mixture and the supplementary titanium silicalite molecular sieve. In general, the duration of the mixing may be from 0.1 to 12 hours, preferably from 0.5 to 6 hours, more preferably from 1 to 3 hours.

In the step (3), the conditions for spray forming may be selected conventionally, and the present invention is not particularly limited thereto. Generally, the inlet temperature for spray forming may be 200-450 deg.C, preferably 250-400 deg.C.

The molecular sieve particles obtained by spray forming in the step (3) can be directly used, for example, directly used as a catalyst; the catalyst may be used after calcination, for example, as a catalyst after calcination. The calcination may be carried out under conventional conditions. Specifically, the calcination may be carried out at a temperature of 300-800 ℃, preferably at a temperature of 450-600 ℃. The duration of the calcination may be from 2 to 12 hours, preferably from 2 to 6 hours. The calcination may be performed in an air atmosphere or an inert atmosphere.

According to the method for preparing sulfoxide, the reaction section can be filled with inactive filler, and the amount of the catalyst in the reaction section can be adjusted by filling the inactive filler in the reaction section, so that the reaction speed and the treatment capacity of the reaction section can be adjusted. The loading of the inactive filler can be suitably selected according to the expected reaction speed and the treatment amount of the reaction section, so as to meet the specific use requirement. Generally, the catalyst may be present in the reaction zone in an amount of from 30 to 95 wt%, preferably from 30 to 90 wt%, more preferably from 50 to 90 wt%, and even more preferably from 60 to 80 wt%, based on the total amount of the inactive filler and catalyst.

The type of the inert filler is not particularly limited, and various inert fillers which are generally used may be used in the present invention, and may be selected from, for example, θ ring, β ring, raschig ring, pall ring, ladder ring, arc saddle, rectangular saddle, and metal ring rectangular saddle.

When the reaction section is also filled with an inactive filler, the inactive filler and the catalyst can be filled in the reaction section in the form of a mixture of the two; the inactive filler and the catalyst can also be loaded in the reaction section at intervals; a combination of the two approaches may also be employed.

According to the method for producing sulfoxide of the present invention, the catalytic distillation reactor is packed with basic ion exchangeAnd replacing the resin, and filling the alkaline ion exchange resin in the alkaline reaction zone and/or the tower bottom of the catalytic distillation reactor. The alkaline reaction zone is positioned in the reaction section, and the theoretical plate number of the position of the upper end of the alkaline reaction zone is t_ar ^uThe theoretical plate number of the position of the lower end of the alkaline reaction zone is t_ar ^bThe number of theoretical plates at which the top of the reaction section is located is T_r ^uThe theoretical plate number of the position where the bottom of the reaction section is positioned is T_r ^bThe theoretical plate number of the reaction section is T_r，t_ar ^uNot less than T_r ^u+0.5T_r(T_r ^u+0.5T_rRepresents a number of 0.5 XT from the top of the reaction section downwards_rBlock theoretical plate), t_ar ^b/T_r ^b≤1。

The total amount of the basic ion exchange resin filled in the basic reaction zone and the tower bottom of the catalytic distillation reactor can be selected according to the filling amount of the titanium silicalite molecular sieve in the catalytic distillation reactor. Generally, the mass ratio of the total amount of basic ion exchange resin charged in the column bottom of the basic reaction zone and the distillation section to the catalyst charged in the reaction section may be 0.01 to 0.3: 1, preferably 0.05 to 0.2: 1, more preferably 0.05 to 0.1: 1.

the alkaline reaction zone can be filled with alkaline ion exchange resin, the tower kettle of the catalytic distillation reactor can be filled with alkaline ion exchange resin, and the alkaline reaction zone and the tower kettle of the catalytic distillation reactor can be filled with alkaline ion exchange resin.

In the alkaline reaction zone, only the alkaline ion exchange resin can be filled, the alkaline ion exchange resin and the catalyst and optional inactive filler can be filled, and the alkaline ion exchange resin and the inactive filler can be filled, preferably the alkaline ion exchange resin is filled, so that better catalytic reaction effect can be obtained.

According to the method for producing a sulfoxide of the present invention, the basic ion exchange resin may be any of various conventional ion exchange resins capable of dissociating basic groups, and may be a strongly basic ion exchange resinThe resin may also be a weakly basic ion exchange resin. In particular, the ion exchange groups in the basic ion exchange resin may be quaternary ammonium groups, -NR¹¹ ₃OH、-NH₂、-NHR¹²and-NR¹³ ₂Wherein R is¹¹、R¹²And R¹³Each is a hydrocarbyl group, preferably an alkyl group, more preferably C₁-C₅Such as methyl, ethyl, n-propyl, isobutyl, n-butyl, isobutyl, tert-butyl or pentyl (including the various isomers of pentyl).

The basic ion exchange resin can be gel type basic ion exchange resin, macroporous type basic ion exchange resin or a mixture of the two. The base material of the basic ion exchange resin may be conventionally selected, such as styrene type basic ion exchange resin, acrylic type basic ion exchange resin, or a mixture of both.

The ion exchange capacity of the basic ion exchange resin is not particularly limited and may be conventionally selected. Generally, the basic ion exchange resin may have a total exchange capacity of from 0.1 to 10 moles/kg, preferably from 0.2 to 6 moles/kg, more preferably from 0.5 to 3 moles/kg. The total exchange capacity is the number of moles of ion exchange groups contained in the ion exchange resin per unit weight, and may be measured under the conditions specified in GB/T8144-2008, or may be obtained from product information of commercially available ion exchange resins. The total exchange content in the examples of the present invention was obtained from product information of commercially available ion exchange resins.

According to the method for preparing sulfoxide of the invention, the titanium silicalite, the basic ion exchange resin and the inactive filler can be filled in the reaction section of the catalytic distillation reactor by conventional methods, such as: the packing can be packed on the tower plate of the reaction section of the catalytic distillation reactor in a bale form, and can also be packed in a loose pile form in the tower plate of the reaction section of the catalytic distillation reactor. The above-mentioned methods may be used alone, or two or more methods may be used in combination. According to the method for producing a sulfoxide of the present invention, the basic ion exchange resin may be packed in a bulk form in a column bottom of a catalytic distillation reactor.

According to the method for producing a sulfoxide of the present invention, the feeding positions of the oxidizing agent, the sulfide and the optional solvent are not particularly limited, and can be determined by a conventional method. Typically, the oxidant is fed to the reaction zone from a first feed inlet and the thioether is fed to the reaction zone from a second feed inlet, the number of theoretical plates from the first feed inlet to the bottom of the reaction zone being T₁The theoretical plate number from the second feeding hole to the bottom of the reaction section is T₂，T₁＞T₂. Preferably, the reaction section has a theoretical plate number T_r，T₁And T_rThe percentage value of (A) is 50-100%, T₂And T_rThe percentage value of (B) is 10-80%. More preferably, T₁And T_rThe percentage value of (A) is 80-100%, T₂And T_rThe percentage value of (B) is 10-40%. Further preferably, T₁And T_rThe percentage value of (A) is 80-90%, T₂And T_rThe percentage value of (B) is 10-30%. The solvent may be fed to the reaction section of the catalytic distillation reactor by various methods commonly used in the art such that contacting the thioether with the oxidant is conducted in the presence of the solvent. For example: the solvent may be fed into the reaction section from the upper part of the reaction section, may be fed into the reaction section from the lower part of the reaction section, and may be fed into the reaction section from the middle part of the reaction section. When the solvent is fed into the reaction section from the lower portion thereof, the solvent is preferably fed into the reaction section at the same position as the oxidant, and more preferably the solvent and the oxidant are fed into the reaction section through the same feed port.

According to the method for preparing a sulfoxide of the present invention, the oxidizing agent may be various substances sufficient to oxidize the sulfide. The process of the present invention is particularly useful where a peroxide is used as the oxidizing agent to oxidize the thioether. 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 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. Specific examples of the peroxide 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. The hydrogen peroxide may be hydrogen peroxide commonly used in the art in various forms, such as hydrogen peroxide provided in the form of hydrogen peroxide.

The oxidizing agent is used in an amount to oxidize the thioether to the sulfoxide. Typically, the molar ratio of the thioether to the oxidizing agent is 1: 0.1 to 2, preferably 1: 0.2-1.5, more preferably 1: 0.5-1.

According to the method for producing a sulfoxide of the present invention, the solvent contains methanol. The solvent may be methanol. The solvent may also be a mixture of methanol with other solvents, in which mixture the methanol content may be from 1 to 99% by weight, for example: 20 to 90 wt% or more, or 50 to 85 wt%. The other solvent may be selected from water, C₂-C₈Alcohol of (1), C₃-C₈Ketone (b), C₂-C₈Nitrile and C₂-C₈And specific examples thereof may include, but are not limited to: one or more of water, ethanol, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone, acetonitrile, propionitrile, phenylacetonitrile and acetic acid.

The amount of the solvent used in the present invention is not particularly limited, and may be selected conventionally. In general, the molar ratio of thioether to solvent may be 1: 0.5 to 200, preferably 1: 5-100, more preferably 1: 6 to 50, more preferably 1: 8-20.

According to the method for producing a sulfoxide of the present invention, the sulfide refers to a compound having a molecular structure containing-S-, and is preferably selected from sulfides having 2 to 18 carbon atoms, more preferably dimethyl sulfide and/or dimethyl sulfide, and particularly preferably dimethyl sulfide.

According to the method for producing a sulfoxide of the present invention, the specific configuration of the catalytic distillation reactor is not particularly limited and may be conventionally selected. Generally, the catalytic distillation reactor has a rectifying section, a reaction section and a stripping section, the reaction section is positioned between the rectifying section and the stripping section, and the theoretical plate number of the reaction section can be 20-45, preferably 30-40.

According to the method for preparing a sulfoxide of the present invention, a thioether and optionally a solvent are used as heating media.

According to the method for preparing sulfoxide, the condition of the contact between the thioether and the oxidant is that the thioether can be oxidized into sulfoxide on one hand, and the oxidation product generated by the contact can be separated from the unreacted thioether on the other hand. Generally, the conditions of the contacting include: the temperature may be 20-200 deg.C, preferably 30-180 deg.C, more preferably 30-120 deg.C, and even more preferably 30-80 deg.C, such as 35-70 deg.C; the reflux ratio may be 1: 1 or more (specifically, 1 to 100: 1), preferably 2: 1 or more (specifically, 2-20: 1, preferably 3-10: 1); the weight hourly space velocity of the thioether can be 0.1-10000h^-1Preferably 1 to 1000h^-1More preferably 2-20h^-1More preferably 2 to 15 hours^-1(ii) a The pressure in the catalytic distillation reactor is 0.01 to 3MPa, preferably 0.1 to 1.5MPa, more preferably 0.1 to 0.5MPa in absolute terms. The reflux ratio is the ratio of the mass of material returned to the reaction zone to the mass of material obtained as product from the reaction zone.

Fig. 1 shows a preferred embodiment of the method for preparing sulfoxides according to the invention. As shown in fig. 1, in this embodiment, hydrogen peroxide in the form of hydrogen peroxide is used as an oxidizing agent, an oxidizing agent storage tank 1 is communicated with the upper portion of the reaction section of the catalytic distillation reactor 11, and the oxidizing agent is fed to the upper portion of the reaction section (i.e., the hatched section in the middle of the catalytic distillation reactor 11); a solvent storage tank 3 is communicated with the upper part or the lower part of the reaction section, the solvent is fed into the upper part or the lower part of the reaction section (preferably, the solvent and the oxidant are fed into the reaction section through the same feed inlet), a thioether storage tank 2 is communicated with the lower part of the reaction section, and thioether is fed into the lower part of the reaction section; the conditions in the catalytic distillation reactor 11 are adjusted to conditions that allow the oxidizing agent to undergo an oxidation reaction with the thioether to form a sulfoxide and to separate the resulting sulfoxide and unreacted thioether from the heavy component stream 10 containing oxidation by-products and water and solvent, etc. by distillation, resulting in a heavy component stream 10 containing sulfoxide, oxidation by-products and water and solvent, etc. at the bottom of the catalytic distillation reactor 11 and a light component stream 7 containing unreacted thioether at the top of the catalytic distillation reactor 11. The light fraction stream 7 is fed to a light fraction separation intermediate tank 4 for gas-liquid separation to obtain a gaseous thioether stream 9 which is fed to a thioether storage tank 2 as a recycle thioether feed stream together with fresh thioether as a thioether feed stream 8 to a catalytic distillation reactor 11. The heavy component stream 10 is sent to a heavy component separation intermediate tank 12 for heavy component separation, the obtained sulfoxide stream enters a sulfoxide primary product tank 13 (further refining and other treatment steps can be carried out), the obtained rest stream enters a solvent separation tank 5, a solvent is separated by a distillation method for example, and at least part of the separated solvent is recycled, so that a stream containing oxidation byproducts is obtained and then sent to a byproduct separation tank 6 for separation, and thus the oxidation byproducts are obtained.

The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.

Preparation examples 1 to 7 were used for preparing catalysts.

In the following preparation examples and comparative preparation examples, the hydrolysis rate 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 a capillary column of HP-5 (30 m.times.320. mu.m.times.25 μm). Wherein the injection port temperature is 220 ℃, the column temperature is 180 ℃, 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 sample from a sample inlet 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:

X_{organic silicon source}％＝[(m^o _{Organic silicon source}-m_{Organic silicon source})/m^o _{Organic silicon source}]×100％

In the formula, X_{Organic silicon source}The hydrolysis rate of the organic silicon source is shown;

m^o _{organic silicon source}Represents the mass of the added organic silicon source;

m_{organic silicon source}The mass of the unhydrolyzed organic silicon source is indicated.

In the following preparation examples and comparative preparations, X-ray diffraction analysis (XRD) was carried out on a Siemens D5005 type X-ray diffractometer, infrared spectroscopic analysis was carried out on a Nicolet 8210 type Fourier infrared spectrometer, the molar composition of the molecular sieve was measured on a 3271E type X-ray fluorescence spectrometer of Nippon Denshi electric Co., Ltd., D50 of the titanium silicalite molecular sieve particles was measured using a laser particle size distribution instrument of Marvin, England, the total specific surface area and the pore volume were measured by the BET method, and the bulk density was measured by the method specified in GB/T6286-1986.

In the following preparation examples and comparative preparation examples, the decomposition rate of the template agent in the hydrothermal crystallization process was calculated by the following method:

the decomposition rate (%) of the template agent was equal to the weight of the oil phase separated after hydrothermal crystallization/the total weight of the template agent added before crystallization × 100%, wherein the weight of the oil phase separated after hydrothermal crystallization and the total weight of the template agent added before crystallization were both calculated as N element.

Reference preparation example 1

This reference is made to the preparation of molecular sieves TS-1 by the method described in Zeolite, 1992, Vol.12, pp.943-950, which is used to illustrate the synthesis of titanium silicalite molecular sieves TS-1 by conventional hydrothermal crystallization.

At room temperature (20 ℃), 22.5 g of ethyl orthosilicate (silicon ester 28, available from xirkat chemical trade ltd, yokkang) was mixed with 7.0 g of tetrapropylammonium hydroxide, and 59.8 g of distilled water was added, and after stirring and mixing, hydrolysis was carried out at normal pressure and 60 ℃ for 1.0 hour to obtain a hydrolyzed solution of ethyl orthosilicate, a solution consisting of 1.1 g of tetrabutyl titanate and 5.0 g of anhydrous isopropyl alcohol was slowly added under vigorous stirring, and the resulting mixture was stirred at 75 ℃ for 3 hours to obtain a clear transparent colloid. Placing the colloid in a stainless steel sealed reaction kettle, and standing at a constant temperature of 170 ℃ for 3 days to obtain a mixture of crystallized products; the mixture was filtered, washed with water, and dried at 110 ℃ for 60 minutes to obtain a molecular sieve raw powder. The molecular sieve raw powder is roasted for 3 hours at the temperature of 550 ℃ in the air atmosphere to obtain the molecular sieve.

Through detection, in an XRD spectrogram of the obtained molecular sieve, a five-finger diffraction characteristic peak which is specific to an MFI structure exists between 22.5-25.0 degrees of 2 theta, and the molecular sieve is shown to have the MFI structure similar to TS-1. Fourier infrared spectrum at 960cm^-1The characteristic absorption peak which the all-silicon molecular sieve does not have appears in the vicinity, and the titanium enters the sample framework. The above characterization results show that the prepared molecular sieve is a titanium silicalite TS-1. The molecular sieve property parameters are listed in table 4.

Mixing the prepared titanium silicalite TS-1 with silica sol according to the following molecular sieve ratio: the weight ratio of silica sol (calculated by silica) is 1: 15 to prepare a slurry, and spray-forming the slurry under the same spray-forming conditions as in preparation example 1 to obtain molecular sieve particles.

Preparation example 1

(1) A50 wt% concentrated solution of tetrapropylammonium hydroxide (the solvent for this concentrated solution is water) was added to deionized water at 20 ℃ under 1 atm with stirring, and mixed for 1 hour to obtain an aqueous solution containing a template.

Tetrabutyl titanate as a titanium source and ethyl orthosilicate (silicon ester 28, same as reference preparation example 1) as an organic silicon source were mixed at 20 ℃ and 1 atm with stirring for 1 hour to obtain a mixture containing the titanium source and the organic silicon source.

An aqueous solution containing a template and a mixture containing a titanium source and an organic silicon source were fed into a reaction vessel in the proportions shown in Table 1, and a hydrolytic condensation reaction was carried out under the reaction conditions shown in Table 1 with stirring to obtain a hydrolytic condensation mixture (the hydrolysis ratio of the organic silicon source is shown in Table 1).

In the hydrolysis condensation reaction process, nitrogen is used for auxiliary purging, steam in the reaction kettle is taken out, the taken steam is condensed by adopting condensed water, the condensate enters a condensate storage tank, and the composition of the condensate is listed in table 2.

(2) And (2) feeding the hydrolysis condensation mixture obtained in the step (1) into a hydrothermal crystallization kettle, adding the condensate collected in the step (1) into the hydrothermal crystallization kettle, and stirring for 3 hours at the temperature of 40 ℃. The amounts of condensate used relative to 100 parts by weight of the hydrolytic condensation mixture (on a dry basis) are listed in Table 3. Next, the hydrothermal crystallization kettle was sealed, the temperature in the hydrothermal crystallization kettle was raised to the hydrothermal crystallization temperature, and hydrothermal crystallization was performed under autogenous pressure, and the conditions of hydrothermal crystallization and the decomposition rate of the template agent during hydrothermal crystallization are shown in table 3.

After the hydrothermal crystallization is completed, the temperature in the hydrothermal crystallization kettle is naturally reduced to 30 ℃, the hydrothermal crystallization kettle is opened, the titanium silicalite TS-1 (prepared by the same method as in reference preparation example 1) is added into the hydrothermal crystallization kettle, and after stirring for 2 hours, the obtained slurry is output. The amount of titanium silicalite TS-1 added is listed in Table 4.

(3) The resulting slurry was spray molded to obtain molecular sieve particles, the spray molding conditions being listed in table 4. And roasting the molecular sieve particles at 550 ℃ for 3 hours in an air atmosphere to obtain the molecular sieve.

Through detection, in an XRD spectrogram of the obtained molecular sieve, a five-finger diffraction characteristic peak which is specific to an MFI structure exists between 22.5-25.0 degrees of 2 theta, and the molecular sieve is shown to have the MFI structure similar to TS-1. Fourier infrared spectrum at 960cm^-1The characteristic absorption peak which the all-silicon molecular sieve does not have appears in the vicinity, and the titanium enters the sample framework. The above characterization results show that the prepared molecular sieve is a titanium silicalite TS-1. The properties of the resulting molecular sieve particles are set forth in table 4.

Preparation of comparative example 1

Adopting the same method as the preparation example 1 to produce the titanium-silicon molecular sieve, except that in the step (2), the condensate collected in the step (1) is not added into the hydrothermal crystallization kettle, but the hydrolysis condensation mixture obtained in the step (1) is sent into the hydrothermal crystallization kettle, stirred for 3 hours at the temperature of 40 ℃, and then the hydrothermal crystallization kettle is sealed for hydrothermal crystallization; and in the step (2), the titanium silicalite TS-1 is not added into the mixture obtained by hydrothermal crystallization.

Through detection, five-finger diffraction characteristic peaks which are special for an MFI structure exist in the XRD crystal phase of the obtained molecular sieve between 22.5-25.0 degrees of 2 theta, and the molecular sieve is shown to have the MFI structure similar to TS-1. Fourier infrared spectrum at 960cm^-1The characteristic absorption peak which the all-silicon molecular sieve does not have appears in the vicinity, and the titanium enters the sample framework. The above characterization results show that the prepared molecular sieve is a titanium silicalite TS-1. The properties of the resulting molecular sieve particles are set forth in table 4.

Preparation of comparative example 2

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 1, except that in step (2), the condensate collected in step (1) was replaced with an equal weight of deionized water.

Preparation of comparative example 3

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 1, except that in step (2), the condensate collected in step (1) was replaced with an equal weight of ethanol.

Preparation of comparative example 4

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 1, except that in step (2), the condensate collected in step (1) was replaced with a mixed solution of water and ethanol (composition listed in table 2) of equal weight.

Preparation of comparative example 5

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 1, except that in step (2), the condensate collected in step (1) was replaced with a mixed solution of water, ethanol and tetrapropylammonium hydroxide (composition shown in table 2) in equal weight.

Preparation example 2

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 1, except that, in step (1), the hydrolytic condensation reaction was carried out under the reaction conditions as listed in table 1.

Through detection, five-finger diffraction characteristic peaks which are special for an MFI structure exist in the XRD crystal phase of the obtained molecular sieve between 22.5-25.0 degrees of 2 theta, and the molecular sieve is shown to have the MFI structure similar to TS-1. Fourier infrared spectrum at 960cm^-1The characteristic absorption peak which the all-silicon molecular sieve does not have appears in the vicinity, and the titanium enters the sample framework. The above characterization results show that the prepared molecular sieve is a titanium silicalite TS-1. The parameters of the properties of the molecular sieve particles obtained are given in Table 4Are listed.

Preparation example 3

Preparation example 4

(1) Tetrapropylammonium hydroxide was mixed with deionized water at 25 ℃ and 1 atm under stirring for 1.5 hours to obtain an aqueous solution containing a template.

Tetraisopropyl titanate as a titanium source and ethyl orthosilicate (silicone ester 40, available from xirkat chemical trade co., york, hong kong) as an organosilicon source were mixed at 25 c under 1 atm for 1.5 hours with stirring to obtain a mixture containing the titanium source and the organosilicon source.

(2) And (2) feeding the hydrolysis condensation mixture obtained in the step (1) into a hydrothermal crystallization kettle, adding the condensate collected in the step (1) into the hydrothermal crystallization kettle, and stirring for 2 hours at the temperature of 50 ℃. The amounts of condensate used relative to 100 parts by weight of the hydrolytic condensation mixture (on a dry basis) are listed in Table 3. Next, the hydrothermal crystallization kettle was sealed, the temperature in the hydrothermal crystallization kettle was raised to the hydrothermal crystallization temperature, and hydrothermal crystallization was performed under autogenous pressure, and the conditions of hydrothermal crystallization and the decomposition rate of the template agent during hydrothermal crystallization are shown in table 3.

After the hydrothermal crystallization is completed, the temperature in the hydrothermal crystallization kettle is naturally reduced to 40 ℃, the hydrothermal crystallization kettle is opened, the titanium silicalite TS-1 (prepared by the same method as the reference preparation example 1) is added into the hydrothermal crystallization kettle, and after stirring for 1 hour, the obtained slurry is output. The amount of titanium silicalite TS-1 added is listed in Table 4.

(3) The resulting slurry was spray molded to obtain molecular sieve particles, the spray molding conditions being listed in table 4. The molecular sieve particles were calcined at 500 ℃ for 4 hours in an air atmosphere to obtain a molecular sieve.

Preparation of comparative example 6

Adopting the same method as that of preparation example 4 to produce a titanium-silicon molecular sieve, except that in step (2), the condensate collected in step (1) is not added into a hydrothermal crystallization kettle, but the hydrolysis condensation mixture obtained in step (1) is fed into the hydrothermal crystallization kettle, stirred at the temperature of 50 ℃ for 2 hours, and then the hydrothermal crystallization kettle is sealed for hydrothermal crystallization; and in the step (2), the titanium silicalite TS-1 is not added into the mixture obtained by hydrothermal crystallization.

Through detection, in an XRD spectrogram of the obtained molecular sieve, a five-finger diffraction characteristic peak which is specific to an MFI structure exists between 22.5-25.0 degrees of 2 theta, and the molecular sieve is shown to have the MFI structure similar to TS-1. Fourier infrared spectrum at 960cm^-1The presence of all-silicon molecules in the vicinityThe characteristic absorption peak absent from the sieve indicates that titanium has entered the sample framework. The above characterization results show that the prepared molecular sieve is a titanium silicalite TS-1. The properties of the resulting molecular sieve particles are set forth in table 4.

Preparation of comparative example 7

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 4, except that in step (2), the condensate collected in step (1) was replaced with a mixed solution of water, ethanol and tetrapropylammonium hydroxide (composition shown in table 2) of equal weight.

Preparation example 5

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 4, except that the amount of the condensate to be used per 100 parts by weight of the hydrolytic condensation mixture (on a dry basis) was as shown in Table 3.

Preparation example 6

(1) Tetrapropylammonium hydroxide was mixed with deionized water at 30 ℃ and 1 atm under stirring for 1 hour to obtain an aqueous solution containing a template.

Tetrabutyl titanate as a titanium source and ethyl orthosilicate (silicon ester 40, available from xiekatt chemical trade co., yokohong) as an organosilicon source were mixed at 30 ℃ and 1 atm under stirring for 1 hour to obtain a mixture containing the titanium source and the organosilicon source.

(2) And (2) feeding the hydrolysis condensation mixture obtained in the step (1) into a hydrothermal crystallization kettle, adding the condensate collected in the step (1) into the hydrothermal crystallization kettle, and stirring for 1 hour at the temperature of 60 ℃. The amounts of condensate used relative to 100 parts by weight of the hydrolytic condensation mixture (on a dry basis) are listed in Table 3. Next, the hydrothermal crystallization kettle was sealed, the temperature in the hydrothermal crystallization kettle was raised to the hydrothermal crystallization temperature, and hydrothermal crystallization was performed under autogenous pressure, and the conditions of hydrothermal crystallization and the decomposition rate of the template agent during hydrothermal crystallization are shown in table 3.

After the hydrothermal crystallization is completed, the temperature in the hydrothermal crystallization kettle is naturally reduced to 40 ℃, the hydrothermal crystallization kettle is opened, the titanium silicalite TS-1 (prepared by the same method as the reference preparation example 1) is added into the hydrothermal crystallization kettle, and after stirring for 3 hours, the obtained slurry is output. The amount of titanium silicalite TS-1 added is listed in Table 4.

(3) The resulting slurry was spray molded to obtain molecular sieve particles, the spray molding conditions being listed in table 4. The molecular sieve particles were calcined at 480 ℃ for 6 hours in an air atmosphere to obtain a molecular sieve.

Through detection, in an XRD spectrogram of the obtained molecular sieve, a five-finger diffraction characteristic peak which is specific to an MFI structure exists between 22.5-25.0 degrees of 2 theta, and the molecular sieve is shown to have the MFI structure similar to TS-1. Fourier infrared spectrum at 960cm^-1NearbyThe characteristic absorption peak which is not existed in the all-silicon molecular sieve appears, which indicates that the titanium enters the sample framework. The above characterization results show that the prepared molecular sieve is a titanium silicalite TS-1. The properties of the resulting titanium silicalite are set forth in table 4.

Preparation of comparative example 8

Adopting the same method as that of preparation example 6 to produce a titanium-silicon molecular sieve, except that in step (2), the condensate collected in step (1) is not added into a hydrothermal crystallization kettle, but the hydrolysis condensation mixture obtained in step (1) is fed into the hydrothermal crystallization kettle, stirred for 1 hour at the temperature of 60 ℃, and then the hydrothermal crystallization kettle is sealed for hydrothermal crystallization; and in the step (2), the titanium silicalite TS-1 is not added into the mixture obtained by hydrothermal crystallization.

Preparation of comparative example 9

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 6, except that in step (2), the condensate collected in step (1) was replaced with a mixed solution of water, ethanol and tetrapropylammonium hydroxide (composition shown in table 2) in equal weight.

Preparation of comparative example 10

The titanium silicalite molecular sieve is produced by the same method as that of preparation example 6, except that in the step (1), nitrogen is not used for purging in the hydrolysis condensation reaction process, and vapor generated in the reaction is condensed and reflows to the reaction kettle. In the step (2), condensate is not added into the hydrothermal crystallization kettle, but the hydrolysis condensation mixture obtained in the step (1) is sent into the hydrothermal crystallization kettle, stirred for 1 hour at the temperature of 60 ℃, and then the hydrothermal crystallization kettle is sealed for hydrothermal crystallization.

Preparation example 7

A titanium silicalite molecular sieve was produced in the same manner as in preparation example 6, except that the amount of the condensate to be used per 100 parts by weight of the hydrolytic condensation mixture (on a dry basis) was as shown in Table 3.

TABLE 1

TABLE 2

Numbering	Alcohol content (% by weight)	Nitrogen content (mmol/L)
			Preparation example 1	91	1.25
Preparation of comparative example 4	91	0
			Preparation of comparative example 5	91	1.25
Preparation example 2	83	2.32
			Preparation example 3	94	0.08
Preparation example 4	88	0.87
			Preparation of comparative example 7	88	0.88
Preparation example 6	92	0.53
			Preparation of comparative example 9	92	0.55

TABLE 3

TABLE 4

¹: the hydrothermal crystallization mixture is calculated by dry basis relative to the addition amount of 1 weight part of hydrothermal crystallization mixture, and the dry basis refers to the mass of the hydrothermal crystallization mixture after being dried at 120 ℃ for 8 hours.

Examples 1 to 19 are intended to illustrate the process for preparing sulfoxides according to the invention.

In the following examples and comparative examples, the θ -ring filler used was obtained from Tianjin Septaxtac technologies, Inc.

Examples 1-9 used a basic ion exchange resin which was a macroporous strongly basic styrenic anion exchange resin available from samsung resin ltd, Anhui and the ion exchange group was-N (CH)₃)₃OH, total exchange capacity 2.8 mol/kg;

examples 10-13 used a basic ion exchange resin which was a macroporous strongly basic acrylic anion exchange resin available from Hangzhou Guangzhou Brilliant resins Ltd and had an ion exchange group of-NH₂Total exchange capacity 0.9 mol/kg;

examples 14-19 used a basic ion exchange resin which was a gel type strongly basic styrene type anion exchange resin available from Daihai chemical industries, Inc. of Shandong,the ion exchange group being-N (CH)₃)₃OH, total exchange capacity 1.5 mol/kg.

In the following examples and comparative examples, the packing in the reaction section was placed on the tray in the form of a bale, and the material filled in the bottom of the catalytic distillation reactor was directly filled in the bottom of the column in a bulk pile.

Examples 1-19 sulfoxide was prepared using the method shown in figure 1, the specific operating procedure was as follows:

communicating an oxidant storage tank 1 with the upper part of a reaction section of a catalytic distillation reactor 11, and feeding an oxidant into the upper part of the reaction section (namely, a section area indicated by shading in the middle of the catalytic distillation reactor 11) through a first feed port; a solvent storage tank 3 is communicated with the upper part or the lower part of the reaction section, a solvent and an oxidant are fed into the reaction section together, a thioether storage tank 2 is communicated with the lower part of the reaction section, and thioether is fed into the lower part of the reaction section through a second feeding hole; the conditions in the catalytic distillation reactor 11 are adjusted to conditions that allow the oxidizing agent to undergo an oxidation reaction with the thioether to form a sulfoxide and to separate the resulting sulfoxide and unreacted thioether from the heavy component stream 10 containing oxidation by-products and water and solvent, etc. by distillation, resulting in a heavy component stream 10 containing sulfoxide, oxidation by-products and water and solvent, etc. at the bottom of the catalytic distillation reactor 11 and a light component stream 7 containing unreacted thioether at the top of the catalytic distillation reactor 11. The light fraction stream 7 is fed to a light fraction separation intermediate tank 4 for gas-liquid separation to obtain a gaseous thioether stream 9 which is fed to a thioether storage tank 2 as a recycle thioether feed stream together with fresh thioether as a thioether feed stream 8 to a catalytic distillation reactor 11. Sending the heavy component stream 10 into a heavy component separation intermediate tank 12 for heavy component separation, sending the obtained sulfoxide stream into a sulfoxide primary product tank 13, sending the obtained rest stream into a solvent separation tank 5 for separating out the solvent by a distillation method for example, and recycling at least part of the separated solvent to obtain a stream containing the oxidation byproducts, and then sending the stream into a byproduct separation tank 6 for separation, thereby obtaining the oxidation byproducts. Wherein, the middle-lower part of the reaction section of the catalytic distillation reactor and/or the kettle bottom of the catalytic distillation reactor is filled with basic ion exchange resin (the specific position is shown in table 5), the reaction section is filled with a mixture of a catalyst and theta ring packing (when the basic ion exchange resin is filled in the basic reaction zone, the catalyst and the theta ring packing are not filled in the basic reaction zone, and when the basic ion exchange resin is not filled in the basic reaction zone, the catalyst and the theta ring packing are filled in the whole reaction section).

The specific reaction conditions for examples 1-19 are set forth in tables 5 and 6. After the apparatus was stabilized, the operation was continued for 120 hours, the composition of the overhead stream of the catalytic distillation reactor was measured by gas chromatography every 10 hours during the reaction, and the selectivity for dimethyl sulfoxide was calculated by the following formula, and the results obtained by each calculation were summed and averaged, and the results are listed in table 7.

Selectivity (%) for dimethylsulfoxide, [ molar amount of dimethylsulfoxide produced by the reaction/(molar amount of added dimethylsulfide-molar amount of unreacted dimethylsulfide) ] × 100%.

During the reaction the composition of the gaseous dimethyl sulphide stream 9 was checked by gas chromatography at intervals of 10 hours, wherein the composition of the gaseous dimethyl sulphide stream 9 was measured and the calculated impurity content at 120 hours of continuous operation is given in table 7.

Comparative examples 1 to 3

Dimethyl sulfoxide was prepared in the same manner as in examples 1 to 19, except that the reaction conditions were as shown in tables 5 and 6 and the experimental results were as shown in table 7.

TABLE 5

¹: the number of theoretical plates from the feed inlet to the bottom of the reaction section.

²: the bottom of the kettle and the alkaline reaction area are not filled with alkaline ion exchange resin.

³: based on the total amount of the catalyst and the theta ring packingThe content of (b) is calculated by titanium silicalite molecular sieve when the catalyst is raw powder of the titanium silicalite molecular sieve, and is calculated by the total amount of the formed titanium silicalite molecular sieve when the catalyst is the formed titanium silicalite molecular sieve.

⁴: molecular sieve raw powder of HTS is commercially available from the company of Jianghuang petrochemical company Limited in Hunan under the trademark.

TABLE 6

¹: relative to the total weight of catalyst loaded in the reaction section.

TABLE 7

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A process for the preparation of a sulfoxide, which process comprises contacting a thioether, at least one oxidant and at least one solvent with a catalyst in a catalytic distillation reactor having at least one reaction zone to obtain a sulfoxide-containing stream and an unreacted thioether-containing stream, the solvent containing methanol and the catalyst containing a titanium silicalite, characterized in that the catalytic distillation reactor is further filled with a basic ion exchange resin, and the basic ion exchange resin is filled in a basic reaction zone and/or a column bottom of the catalytic distillation reactor, the basic reaction zone is located in the reaction zone, and the basic reaction is carried out in a reverse reaction zoneThe theoretical plate number of the upper end of the reaction zone is t_ar ^uThe theoretical plate number of the position of the lower end of the alkaline reaction zone is t_ar ^bThe number of theoretical plates at which the top of the reaction section is located is T_r ^uThe theoretical plate number of the position where the bottom of the reaction section is positioned is T_r ^bThe theoretical plate number of the reaction section is T_r，t_ar ^uNot less than T_r ^u+0.5T_r，t_ar ^b/T_r ^b≤1。

2. The process according to claim 1, wherein the mass ratio of the total amount of basic ion exchange resin to the catalyst is from 0.01 to 0.3: 1, preferably 0.05 to 0.2: 1, more preferably 0.05 to 0.1: 1.

3. the process of claim 1, wherein the oxidant is fed into the reaction zone from a first feed inlet and the thioether is fed into the reaction zone from a second feed inlet, the theoretical plate number from the first feed inlet to the bottom of the reaction zone being T₁The theoretical plate number from the second feeding hole to the bottom of the reaction section is T₂，T₁＞T₂；

Preferably, the reaction section has a theoretical plate number T_r，T₁And T_rThe percentage value of (A) is 50-100%, T₂And T_rThe percentage value of (A) is 10-80%;

more preferably, T₁And T_rThe percentage value of (A) is 80-100%, T₂And T_rThe percentage value of (A) is 10-40%;

further preferably, the solvent and the oxidant are fed into the reaction section through the same feed port.

4. The process of claim 1, wherein the catalyst is prepared by a process comprising:

5. The method of claim 4, wherein in step (1), the molar ratio of the organic silicon source, the titanium source, the template agent and the water is 100: (0.005-10): (0.005-40): (200-10000), preferably 100: (0.05-8): (0.5-30): (500- & ltSUB & gt 5000- & gt), more preferably 100: (0.2-6): (5-25): (800-4000), more preferably 100: (1-5): (10-20): (1500-3000), the organic silicon source is SiO₂The titanium source is calculated as TiO₂In terms of NH, the template agent₃And (6) counting.

6. The method of claim 4 or 5, wherein the preparation of the mixture comprising the source of titanium and the source of organic silicon comprises: the titanium source and the organic silicon source are mixed with stirring at 0 to 60 ℃, preferably 15 to 40 ℃, more preferably 20 to 30 ℃ for 1 to 2 hours.

7. The method according to any one of claims 4 to 6, wherein the organic silicon source is selected from silicon-containing compounds of formula I,

in the formula I, R₁、R₂、R₃And R₄Each is C₁-C₄Alkyl groups of (a);

preferably, the organic silicon source is one or more than two selected from methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, isopropyl orthosilicate and n-butyl orthosilicate;

the titanium source is TiCl₄、Ti(SO₄)₂、TiOCl₂One or more than two of titanium hydroxide, titanium oxide, titanium nitrate, titanium phosphate, tetraisopropyl titanate, tetra-n-propyl titanate, tetrabutyl titanate and tetraethyl titanate.

8. The method according to any one of claims 4 to 7, wherein the template is one or more of urea, amine, alcohol amine and quaternary ammonium base;

preferably, the template agent is a quaternary ammonium base shown in a formula II,

in the formula II, R₅、R₆、R₇And R₈Are the same or different and are each C₁-C₄Alkyl groups of (a);

more preferably, the templating agent is tetraethylammonium hydroxide and/or tetrapropylammonium hydroxide.

9. A method according to any one of claims 4-8, wherein the condensate comprises water and alcohol, the alcohol being present in an amount of 80-96 wt.%, preferably 83-95 wt.%, more preferably 88-92 wt.%, and the water being present in an amount of 4-20 wt.%, preferably 5-17 wt.%, more preferably 8-12 wt.%, based on the total amount of the condensate;

preferably, the condensate contains nitrogen, and the concentration of nitrogen in the condensate is preferably 0.01 to 50mmol/L, more preferably 0.02 to 20mmol/L, still more preferably 0.04 to 5mmol/L, still more preferably 0.05 to 3mmol/L, and particularly preferably 0.5 to 1.5 mmol/L.

10. The process according to any one of claims 4 to 9, wherein in step (2), the condensate is used in an amount of 1 to 50 parts by weight, preferably 1.5 to 40 parts by weight, more preferably 2 to 30 parts by weight, and still more preferably 10 to 25 parts by weight, relative to 100 parts by weight of the hydrolytic condensation mixture.

11. The method according to any one of claims 4 to 10, wherein in step (1), the hydrolysis condensation reaction conditions are such that the hydrolysis rate of the organic silicon source is 85 to 100%, preferably 90 to 100%, more preferably 93 to 100%, and still more preferably 95 to 99%;

preferably, the contacting is carried out at a temperature of 80-98 ℃, preferably 85-95 ℃;

more preferably, in step (1), the duration of said contact is between 4 and 36 hours, preferably between 6 and 28 hours, more preferably between 12 and 16 hours.

12. The process according to any one of claims 4 to 11, wherein in step (2) the hydrolytic condensation mixture is mixed with a portion of the condensate with stirring at a temperature of 20 to 80 ℃, preferably 40 to 60 ℃, for 1 to 6 hours.

13. The method as claimed in claim 4 or 12, wherein, in the step (2), the hydrothermal crystallization is carried out at a temperature of 120-;

preferably, in step (2), the duration of the hydrothermal crystallization is 6 to 48 hours, preferably 8 to 36 hours, and more preferably 10 to 24 hours.

14. The method of claim 4, wherein in step (3), the weight ratio of the supplemental titanium silicalite molecular sieves to the hydrothermal crystallization mixture is from 0.01 to 10: 1, preferably 0.05 to 8: 1, more preferably 0.2 to 5: 1, more preferably 0.4 to 3: 1, the hydrothermal crystallization mixture is on a dry basis.

15. The process of any one of claims 1 and 4 to 14, wherein the titanium silicalite in the catalyst is a titanium silicalite of MFI structure, preferably a titanium silicalite TS-1 and/or a hollow titanium silicalite.

16. The method of claim 1, wherein the molar ratio of the thioether to the oxidizing agent is 1: 0.1-2.

17. The process according to claim 1 or 16, wherein the oxidizing agent is a peroxide, preferably one or more selected from the group consisting of hydrogen peroxide, t-butyl hydroperoxide, ethylbenzene hydroperoxide, cumene hydroperoxide, cyclohexyl hydroperoxide, peracetic acid and peroxopropionic acid, more preferably hydrogen peroxide.

18. The process according to claim 1, wherein the molar ratio of thioether to solvent is 1: 0.5-200.

19. The method of claim 1 or 18, wherein the content of methanol in the solvent is 1-99 wt%.

20. The method of any one of claims 1-19, wherein the sulfide is dimethyl sulfide.

21. The method of any one of claims 1-20, wherein the conditions of the contacting comprise: the temperature is 20-200 ℃; the reflux ratio is 1-100: 1; the weight hourly space velocity of the thioether is 0.1-10000h^-1(ii) a The pressure in the catalytic distillation reactor is 0.01-3MPa in absolute pressure.