CN103288692B - A kind of method being prepared dimethyl sulfone by dimethyl sulfoxide (DMSO) - Google Patents

Abstract

The invention discloses a method for preparing dimethyl sulfoxide from dimethyl sulfoxide. The method comprises: under oxidation reaction conditions, dimethyl sulfoxide is contacted with an oxidizing agent, and the oxidizing agent is characterized in that the oxidizing agent contains ozone gas. The method has high dimethyl sulfone selectivity, especially in the presence of a titanium-containing catalyst, and the effective utilization rate of ozone is also greatly improved.

Description

A kind of method preparing dimethyl sulfone by dimethyl sulfoxide

technical field

The present invention relates to a method for preparing dimethyl sulfone from dimethyl sulfoxide.

Background technique

Dimethylsulfone, alias methylsulfonylmethane, English name: Dimethylsulfone, MethylSulfonylMethane (MSM), is a white crystalline powder, easily soluble in ether water, ethanol, benzene, methanol and acetone, slightly soluble in ether. Potassium permanganate cannot be discolored at room temperature, and strong oxidizing agents can oxidize dimethyl sulfone to methanesulfonic acid. Aqueous solution of dimethyl sulfone is neutral. Sublimation occurs in a small amount at 25°C, and the sublimation speed is accelerated at 60°C, so the drying of dimethyl sulfone products is easy to be carried out under low temperature and vacuum.

Dimethyl sulfone is used in industry as a high-temperature solvent and raw material for organic synthesis, as a stationary liquid for gas chromatography, as an analytical reagent, as a food additive and as a drug. As an organic sulfide, MSM has the ability to enhance the production of insulin in the human body and promote the metabolism of carbohydrates. It is a necessary substance for the synthesis of human collagen. It can promote wound healing, and can also play a role in the synthesis and activation of vitamin B, vitamin C, and biotin required for metabolism and nerve health. It is called "natural beautifying carbon substance". Contained in the skin, hair, nails, bones, muscles and various organs of the human body, it mainly exists in the ocean and soil in nature, and is absorbed as nutrients during plant growth. Humans can obtain it from vegetables, fruits, fish, meat, Ingestion from foods such as eggs and milk, once lacking, will cause health disorders or diseases. It is the main substance for the human body to maintain the balance of biological sulfur elements. It has therapeutic value and health care functions for human diseases, and is an essential drug for human survival and health protection. , foreign countries use it as a nutritional product that is equally important as vitamins. The research on the application of dimethyl sulfone in my country has not yet been carried out well, so the current products are all used for export. Dimethyl sulfone is a high-tech product and a high value-added fine chemical product. The product is new, the market potential is great, the profit is outstanding, and it can export and earn foreign exchange, so it has broad prospects for production and application development.

At present, dimethyl sulfone, as the product of further oxidation of dimethyl sulfoxide, is the main by-product of dimethyl sulfoxide production. In addition, dimethyl sulfone can also be obtained directly from dimethyl sulfoxide by nitric acid oxidation. Oxidize dimethyl sulfoxide with nitric acid at 140-145°C. After the reaction, cool it down and filter to obtain a crude product of white needle crystals. After vacuum distillation, the fraction at 138-145°C (98.42kPa) is collected as the finished product.

Contents of the invention

The purpose of the present invention is to provide a method for preparing dimethyl sulfone from dimethyl sulfoxide with simple process, low cost and good dimethyl sulfone selectivity.

The inventors of the present invention have carried out in-depth research and found that using ozone as an oxidizing agent to oxidize dimethyl sulfoxide is environmentally friendly and can obtain satisfactory dimethyl sulfone selectivity and effective utilization of the oxidizing agent, thereby completing the invention.

Therefore, the present invention provides a method for preparing dimethyl sulfoxide from dimethyl sulfoxide, the method comprising, under oxidation reaction conditions, contacting dimethyl sulfoxide with an oxidizing agent, characterized in that the oxidizing agent is Gases containing ozone.

The method for preparing dimethyl sulfone from dimethyl sulfoxide provided by the invention overcomes the problems of complicated traditional production process, long oxidation time, low efficiency, high cost and harmful emission. The present invention uses ozone as the oxidizing agent without adding any inhibitor or initiator to the feed gas, the production process is simple, easy to control, and the selectivity of dimethyl sulfone is high, especially in the presence of a titanium-containing catalyst, the effective utilization rate of the oxidant ozone is further improved improve.

detailed description

The invention provides a method for preparing dimethyl sulfone, the method comprising, under oxidation reaction conditions, contacting dimethyl sulfoxide with an oxidizing agent, characterized in that the oxidizing agent is a gas containing ozone.

According to the method of the present invention, an ozone-containing gas is used as an oxidizing agent. Ozone (molecular formula is O ₃ , also known as triatomic oxygen, commonly known as "Fu oxygen, super oxygen, active oxygen") is a light blue gas at normal temperature and pressure. The inventors of the present invention found during the research process that using ozone-containing gas as an oxidant to oxidize dimethyl sulfoxide has high selectivity to dimethyl sulfone, and the process is simple and easy, and the operating conditions are mild. Moreover, ozone can be decomposed into oxygen by itself at room temperature, and there will be no disadvantages such as the need to process a solution containing hydrogen peroxide, which is faced when hydrogen peroxide is used as an oxidant. Therefore, the method according to the invention is environmentally friendly.

According to the method of the present invention, the ozone-containing gas may be ozone, or a mixed gas of ozone and diluent gas. According to the method of the present invention, the gas containing ozone is preferably a mixed gas of ozone and diluent gas, so that the concentration of ozone can be adjusted conveniently, so as to better control the reaction rate.

In the present invention, when the ozone-containing gas is a mixed gas of ozone and a diluent gas, the concentration of ozone in the mixed gas can be properly selected according to specific oxidation reaction conditions. Preferably, based on the total volume of the mixed gas, the content of ozone in the mixed gas is more than 1% by volume. More preferably, based on the total volume of the mixed gas, the content of ozone in the mixed gas is more than 5% by volume. Generally, based on the total volume of the mixed gas, the content of ozone in the mixed gas may be 5-80% by volume, preferably 5-50% by volume, more preferably 5-20% by volume.

The present invention has no particular limitation on the type of the diluent gas, for example, the diluent gas may be at least one of oxygen, carbon dioxide, nitrogen, argon, helium, neon and air. Preferably, the diluent gas is at least one of oxygen, carbon dioxide, helium and air. According to the present invention, ozone can be mixed with the above diluent gas to prepare the ozone-containing mixed gas; since air contains oxygen, carbon dioxide and nitrogen, ozone can also be mixed with air to prepare the ozone-containing mixed gas. According to the method of the present invention, when an ozone generator is used to generate ozone on site, oxygen can be used as the oxygen source of the ozone generator, and air can also be used to provide oxygen to the ozone generator. The purity of the ozone that adopts oxygen as the oxygen source of described ozone generator to obtain is higher, can obtain higher dimethyl sulfoxide conversion rate, dimethyl sulfone selectivity; Adopt air as the oxygen source of described ozone generator , it can further reduce the operating cost.

According to the method of the present invention, when the oxidizing agent is a mixed gas of ozone and diluent gas, and there are two or more kinds of diluent gases, the present invention does not specifically limit the content of each diluent gas, as long as the final ozone-containing In the gas, it is enough that the content of ozone can oxidize dimethyl sulfoxide, for example: the content of the ozone can be the above-mentioned ozone content.

In a preferred embodiment of the present invention, the ozone-containing gas is ozone or a mixed gas of ozone and diluent gas, and based on the total volume of the mixed gas, the amount of ozone in the mixed gas The content is more than 1% by volume, and the diluent gas is at least one of oxygen, carbon dioxide, nitrogen, argon, helium, neon and air. In a more preferred embodiment according to the present invention, based on the total volume of the mixed gas, the content of ozone in the mixed gas is more than 5% by volume, and the diluent gas is oxygen, carbon dioxide, helium At least one of gas and air.

According to the method of the present invention, by using the gas containing ozone as the oxidant, the purpose of preparing dimethyl sulfone under mild operating conditions and high selectivity is realized, and at the same time, the purpose of not causing serious corrosion to the equipment. The present invention has no special requirements on the molar ratio of dimethyl sulfoxide to ozone in the oxidizing agent, and can be properly selected according to specific application occasions. Under the conditions of ensuring the conversion rate of dimethyl sulfoxide and the selectivity of dimethyl sulfone, from the perspective of further reducing the amount of ozone and further reducing the cost of the method according to the present invention, the dimethyl sulfoxide The molar ratio of ozone to the oxidizing agent is preferably 1:0.1-10, more preferably 1:0.1-5, even more preferably 1:0.5-5.

According to the method of the present invention, the contacting of dimethyl sulfoxide with the oxidizing agent is preferably carried out in the presence of a titanium-containing catalyst. The inventors of the present invention found in the research process that when the contact of dimethyl sulfoxide and the oxidizing agent was carried out in the presence of a titanium-containing catalyst, the conversion rate of dimethyl sulfoxide in the method of the present invention can be improved, especially can be greatly improved. Greatly improve the effective utilization rate of the oxidant ozone.

According to the method of the present invention, the amount of the titanium-containing catalyst can be properly selected according to specific application occasions. Preferably, based on titanium dioxide, the molar ratio of the titanium-containing catalyst to dimethyl sulfoxide is 1:0.1-100. More preferably, based on titanium dioxide, the molar ratio of the titanium-containing catalyst to dimethyl sulfoxide is 1:1-50.

According to the method of the present invention, the titanium-containing catalyst may be various forms of titanium-containing catalysts. Preferably, the titanium-containing catalyst is at least one of titanium-containing molecular sieves, shaped catalysts containing titanium molecular sieves, amorphous silicon titanium and titanium dioxide. More preferably, the titanium-containing catalyst is titanium-silicon molecular sieve with MFI structure (such as TS-1), titanium-silicon molecular sieve with MEL structure (such as TS-2), titanium-silicon molecular sieve with BEA structure (such as Ti-Beta), MWW Structured titanium-silicon molecular sieve (such as Ti-MCM-22), hexagonal structure titanium-silicon molecular sieve (such as Ti-MCM-41, Ti-SBA-15), MOR structure titanium-silicon molecular sieve (such as Ti-MOR), TUN structure At least one of titanium-silicon molecular sieves (such as Ti-TUN), titanium-silicon molecular sieves of other structures (such as Ti-ZSM-48) and titanium dioxide. More preferably, the titanium-containing catalyst is a titanium-silicon molecular sieve with an MFI structure (such as TS-1). The above-mentioned molecular sieves can be obtained commercially, or synthesized by methods known in the art, and will not be described in detail herein.

According to the method of the present invention, the titanium-containing catalyst is most preferably a titanium-silicon molecular sieve with an MFI structure of hollow structure crystal grains, the radial length of the cavity part of the hollow structure is 5-300 nanometers, and the titanium-silicon molecular sieve is The benzene adsorption measured under the conditions of 25°C, P/P ₀ =0.10, and adsorption time of 1 hour is at least 70 mg/g, and the low-temperature nitrogen adsorption of the titanium-silicon molecular sieve is between the adsorption isotherm and the desorption isotherm There is a hysteresis loop. Hereinafter, this type of titanium-silicon molecular sieve is called hollow titanium-silicon molecular sieve.

According to the method of the present invention, the contact between dimethyl sulfoxide and oxidant is preferably carried out in the presence of a solvent, which can make the contact between dimethyl sulfoxide and oxidant more uniform, thereby better controlling the reaction rate. The present invention does not specifically limit the type of the solvent, and the solvent may be various solvents commonly used in the art. Preferably, the solvent is at least one of water, C ₁ -C ₁₀ alcohol, C ₃ -C ₁₀ ketone, C ₂ -C ₈ nitrile and C ₁ -C ₆ carboxylic acid. For example, the solvent may be at least one of water, methanol, ethanol, n-propanol, isopropanol, tert-butanol, isobutanol, acetone, butanone, acetonitrile and acetic acid. The inventors of the present invention unexpectedly discovered during the research process that when the solvent is water and/or C ₃ -C ₈ ketones, the conversion rate of dimethyl sulfoxide and the selectivity of dimethyl sulfoxide can be further improved . Further preferably, the solvent is water, butanone and/or acetone.

According to the method of the present invention, the amount of the solvent can be conventionally selected in the art. From the perspective of further reducing the cost of the method of the present invention, the molar ratio of dimethyl sulfoxide to solvent is preferably 1:1-150, more preferably 1:1-100, and even more preferably 1:1-50 .

According to the method of the present invention, there is no special requirement for the oxidation reaction conditions, which may be conventional oxidation reaction conditions. Preferably, the oxidation reaction conditions include: the temperature can be 0-180°C, preferably 20-160°C, more preferably 20-120°C; the pressure can be 0.1-3MPa, preferably 0.1-2.5MPa, more preferably 0.1-2MPa. According to the method of the present invention, the contact time of dimethyl sulfoxide and the oxidizing agent can be properly selected. Generally, the contacting time may be 0.1-10 hours, preferably 1-5 hours. It should be noted that, when the required pressure can be generated at the temperature, the pressure can be an autogenous pressure; when the pressure generated by the temperature cannot reach the required pressure at the temperature, The pressure can be achieved by external pressure, which is a well-known technique in the art, and will not be described in detail herein.

According to the method of the present invention, conventional methods can be used to separate dimethyl sulfone from the contact product of dimethyl sulfoxide and an oxidizing agent. For example: Dimethyl sulfone can be isolated by subjecting the contact product to fractional distillation under reduced pressure. The methods and conditions of the fractionation are well known in the art, and will not be repeated here.

According to the method of the present invention, batch operation can be adopted, continuous operation can also be adopted, and the feeding method can also be any suitable mode known to those skilled in the art. The present invention has no special requirements to this, and will not go into details here. . During continuous operation, the reaction is carried out under the condition that the ozone space velocity is 10-10000h ^-1 in the presence of a titanium-containing catalyst, and the ozone space velocity is preferably 10-5000h ^-1 .

The following examples will further illustrate the present invention, but do not limit the content of the present invention.

In the examples, unless otherwise specified, the reagents used are commercially available analytical reagents, and the reactor used is a general-purpose 250mL stainless steel autoclave reactor.

In the embodiment, the ozone used is provided by the NLO-15 ozone generator produced by Fujian Newland Environmental Protection Technology Co., Ltd. The ozone concentration is adjustable, and the maximum volume concentration can reach 80%. In the following examples, unless otherwise specified, an oxygen source is used to prepare ozone.

In the embodiment, the titanium-silicon molecular sieve (TS-1) catalyst used is the TS-1 molecular sieve sample prepared by the method described in the literature [Zeolites, 1992, Vol.12 pages 943-950], and the titanium oxide content is 2.4% by weight.

In the embodiment, the hollow titanium-silicon molecular sieve HTS used is an industrial product of the titanium-silicon molecular sieve described in CN1301599A (manufactured by Hunan Jianchang Petrochemical Co., Ltd., analyzed as a titanium-silicon molecular sieve of MFI structure by X-ray diffraction, and the low-temperature nitrogen of the molecular sieve There is a hysteresis loop between the adsorption isotherm and the desorption isotherm, the grains are hollow grains and the radial length of the cavity part is 15-180 nanometers; the molecular sieve sample is at 25°C, P/P ₀ =0.10, The benzene adsorption measured under the condition of an adsorption time of 1 hour was 78 mg/g), and the titanium oxide content was 2.5% by weight.

In the present invention, the analysis of each composition in the system is carried out by gas chromatography, and the quantification is carried out by the calibration and normalization method, both of which can be carried out with reference to the prior art. On this basis, evaluation indicators such as the conversion rate of the reactant and the selectivity of the product are calculated.

In the example:

Example 1

At a temperature of 60°C and a pressure of 0.5 MPa, with ozone (15% by volume, the rest being oxygen) as an oxidant, dimethyl sulfoxide, ozone and solvent acetone are reacted in a molar ratio of 1:1:1 . The results of the reaction for 2 hours are as follows: the conversion rate of dimethyl sulfoxide is 74%; the effective utilization rate of ozone is 76%; the selectivity of dimethyl sulfone is 99%.

Example 2

At a temperature of 20°C and a pressure of 1.5 MPa, with ozone (30% by volume, the rest being air) as an oxidant, dimethyl sulfoxide, ozone and solvent acetic acid are reacted in a molar ratio of 1:1:5 . The results of the reaction for 5 hours are as follows: the conversion rate of dimethyl sulfoxide is 53%; the effective utilization rate of ozone is 81%; the selectivity of dimethyl sulfone is 97%.

Example 3

At a temperature of 80°C and a pressure of 0.2 MPa, with ozone (5% by volume, the rest being oxygen) as an oxidant, dimethyl sulfoxide, ozone and solvent methanol are reacted in a molar ratio of 1:2:10 . The results of the reaction for 2 hours are as follows: the conversion rate of dimethyl sulfoxide is 93%; the effective utilization rate of ozone is 74%; the selectivity of dimethyl sulfone is 97%.

Example 4

At a temperature of 40°C and a pressure of 0.1 MPa, with ozone (15% by volume, the rest being oxygen) as an oxidant, dimethyl sulfoxide, ozone and solvent acetone are reacted in a molar ratio of 1:4:50 . The results of the reaction for 3 hours are as follows: the conversion rate of dimethyl sulfoxide is 91%; the effective utilization rate of ozone is 73%; the selectivity of dimethyl sulfone is 98%.

Example 5

This example illustrates the reaction procedure and results in the presence of a catalyst.

TS-1 was used as the catalyst, the molar ratio of catalyst to dimethyl sulfoxide was 1:100, the volume space velocity of ozone was 20h ^-1 , and other reaction conditions were the same as in Example 4. The results of the reaction for 3 hours are as follows: the conversion rate of dimethyl sulfoxide is 98%; the effective utilization rate of ozone is 86%; the selectivity of dimethyl sulfone is 98%.

Example 6

This example illustrates the reaction procedure and results in the presence of a catalyst.

The reaction was carried out according to the reaction conditions of Example 5, except that HTS was used instead of TS-1 as the catalyst. The results of the reaction for 3 hours are as follows: the conversion rate of dimethyl sulfoxide is 99%; the effective utilization rate of ozone is 91%; the selectivity of dimethyl sulfone is 99%.

Example 7

At a temperature of 50°C and a pressure of 1.0 MPa, with ozone (10% by volume, the rest being air) as an oxidant, dimethyl sulfoxide, ozone and solvent acetone are reacted in a molar ratio of 1:0.3:3 . The results of the reaction for 4 hours are as follows: the conversion rate of dimethyl sulfoxide is 24%; the effective utilization rate of ozone is 71%; the selectivity of dimethyl sulfone is 97%.

Example 8

At a temperature of 90°C and a pressure of 1.0 MPa, with ozone (10% volume ratio, the rest being carbon dioxide and oxygen at a volume ratio of 7:10) as the oxidant, dimethyl sulfoxide, ozone, and solvent water were mixed at a ratio of 1:0.7 : 5 molar ratio. The results of the reaction for 3 hours are as follows: the conversion rate of dimethyl sulfoxide is 51%; the effective utilization rate of ozone is 74%; the selectivity of dimethyl sulfone is 95%.

Example 9

This example illustrates the reaction procedure and results in the presence of a catalyst.

TiO ₂ was used as catalyst (commercially available, anatase type), the molar ratio of catalyst to dimethyl sulfoxide was 1:20, the volume space velocity in ozone was 5000h ^-1 , and other reaction conditions were the same as in Example 8. The result of reaction for 1 hour is as follows: the conversion rate of dimethyl sulfoxide is 57%; the effective utilization rate of ozone is 86%; the selectivity of dimethyl sulfone is 97%.

Example 10

At a temperature of 100°C and a pressure of 2.0 MPa, with ozone (10% volume ratio, the rest being equal volumes of helium and oxygen) as the oxidant, dimethyl sulfoxide, ozone and solvent acetonitrile were mixed in a ratio of 1:2:60 react at a molar ratio. The result of reacting for 1 hour is as follows: the conversion rate of dimethyl sulfoxide is 83%; the effective utilization rate of ozone is 78%; the selectivity of dimethyl sulfone is 95%.

Example 11

This example illustrates the reaction procedure and results when the solvent is water.

The reaction was carried out according to the reaction conditions of Example 10, except that water was used instead of acetonitrile as the solvent. The result of reacting for 1 hour is as follows: the conversion rate of dimethyl sulfoxide is 87%; the effective utilization rate of ozone is 84%; the selectivity of dimethyl sulfone is 97%.

Example 12

This example illustrates the reaction procedure and results in the presence of a catalyst.

HTS was used as the catalyst, the molar ratio of catalyst to dimethyl sulfoxide was 1:10, the volume space velocity of ozone was 1000h ^-1 , and other reaction conditions were the same as in Example 11. The result of reacting for 1 hour is as follows: the conversion rate of dimethyl sulfoxide is 95%; the effective utilization rate of ozone is 90%; the selectivity of dimethyl sulfone is 99%.

Claims (3)

1. A method for preparing dimethyl sulfone by dimethyl sulfoxide, the method is under oxidation reaction conditions, dimethyl sulfoxide is contacted with an oxidizing agent, it is characterized in that said contact exists in a solvent and contains titanium Under the catalyst, the molar ratio of the dimethyl sulfoxide to the solvent is 1:1-150, the oxidant is a gas containing ozone, and the molar ratio of the dimethyl sulfoxide to the ozone in the oxidant is 1: 0.1-10, the solvent is water or acetone, the oxidation reaction conditions include: the temperature is 40-100 ° C, the pressure is 0.1-3 MPa, the time is 0.1-10 hours, and the titanium-containing catalyst is titanium silicon with MFI structure Molecular sieve, the crystal grain is a hollow structure, the radial length of the cavity part of the hollow structure is 5-300 nanometers, and the titanium-silicon molecular sieve is under the conditions of 25°C, P/P ₀ =0.10, and an adsorption time of 1 hour The measured benzene adsorption amount is at least 70 mg/g, and there is a hysteresis loop between the adsorption isotherm and the desorption isotherm of the low-temperature nitrogen adsorption of the titanium-silicon molecular sieve. In terms of titanium dioxide, the catalyst and dimethyl sulfoxide The molar ratio is 1:0.1-100, and the ozone space velocity is 20-5000h ^-1 . 2. according to the method for claim 1, wherein, said gas containing ozone is the mixed gas of ozone or ozone and diluent gas, and with the total volume of described mixed gas as benchmark, the content of ozone in described mixed gas is More than 1% by volume, the diluent gas is at least one of oxygen, carbon dioxide, nitrogen, argon, helium, neon and air. 3. according to the method for claim 2, wherein, take the total volume of described mixed gas as benchmark, the content of ozone in described mixed gas is more than 5 volume %, and described dilution gas is oxygen, carbon dioxide, helium and air at least one of .