Dimethyl sulfoxide(DMSO) is a sulfur-containing organic compound CAS NO.67-68-5

Dimethyl sulfoxide is generally obtained by oxidation of dimethyl sulfide. Due to the different oxidants and oxidation methods used, there are different production processes.
1. Methanol carbon disulfide method
Methanol and carbon disulfide are used as raw materials. Gamma-Al2O3 is used as a catalyst to synthesize dimethyl sulfoxide and then oxidize with nitrogen dioxide(or nitric acid) to obtain dimethyl sulfoxide.
2. Peroxic water method
Using acetone as a buffer medium, dimethyl sulfide reacts with hydrogen peroxide. The production of dimethyl sulfoxide by this method is expensive and is not suitable for large-scale production.
3. Nitrogen dioxide method
dimethyl sulfide is produced by methanol and hydrogen sulfide under the action of gamma-aluminum oxide; Sulfate reacts with sodium nitrite to produce nitrogen dioxide; Dimethylthioether is then oxidized with nitrogen dioxide at 60-80 °C to produce crude dimethyl sulfoxide, and it is also oxidized directly with oxygen. It also produces crude dimethyl sulfoxide, which is then distilled under vacuum and refined. Dimethyl sulfoxide finished product. This method is a relatively advanced production method.
4. Dimethylsulfate method
Dimethyl sulfide was prepared by reacting dimethyl sulfate with sodium sulfide; Sulfate reacts with sodium nitrite to produce nitrogen dioxide; Dimethylthioether and nitrogen dioxide are oxidized to give coarse dimethyl sulfoxide, which is then neutralized and distilled to obtain dimethyl sulfoxide. In addition, dimethyl sulfoxide is produced from dimethyl sulfide by anodizing.
Refining method: Decompression distillation of dimethyl sulfoxide, adding aluminum oxide to be placed overnight, using a distillation tower with a height of 50cm and filled with pottery saddle-shaped fillers, and vacuum distillation at 266.6 ~ 399.9 Pa, 50 °C to collect intermediate fractions. Or dimethyl sulfoxide is heated together with CaH2 for one day. After vacuum distillation, it is dried with a molecular sieve, and vacuum distillation is performed under nitrogen flow. It can also be crystallized and refined step by step.
5. Dimethyl sulfoxide was obtained by the oxidation of dimethyl sulfoxether(obtained by reacting dimethyl sulfate with sodium sulfide) and nitrogen dioxide(obtained by reacting sulfuric acid with sodium nitrite) at 60 ~ 80 °C to obtain dimethyl sulfoxide crude product., Then vacuum distillation, the use of molecular sieve water before decompression distillation, that is, the finished product dimethyl sulfoxide. The main reaction formula is:
6. Using acetone as a buffer medium, adding dimethyl sulfide and hydrogen peroxide of equal mass, stirring reaction, maintaining the temperature at 20 °C:
After the reaction is over, dimethyl sulfoxide with higher purity can be obtained by direct vacuum distillation.

1, used for aromatic hydrocarbon extraction, reaction media for resins and dyes, acrylic fiber polymerization, solvent for drawing wires, etc..
2, can be used as organic solvents, reaction media and organic synthesis intermediates. Very widely used. This product has a high selective extraction ability and is used as a polymerization and condensation solvent for acrylic resins and polysulfone esters, a polymerized wire extraction solvent for polyacrylonitrile and acetic acid fibers, and an extraction solvent for separation of alkanes from aromatic hydrocarbons. Used for aromatic hydrocarbons, butadiene extraction, The reaction media of acrylic fiber spinning, plastic solvent and organic synthetic dyes, pharmaceuticals and other industries. In medicine, dimethylene sulfoxide has an anti-inflammatory and analgesic effect and has a strong osmotic effect on the skin, so that certain drugs can be dissolved and such drugs can penetrate the human body to achieve therapeutic purposes. Using this carrier property of dimethyl sulfoxide can also be used as an additive to pesticides. Adding a small amount of dimethyl sulfoxide to some pesticides helps the pesticide penetrate into the plant to increase its efficacy. Dimethyl sulfoxide can also be used as a dye solvent, dedye, and dye carrier for synthetic fibers. It can also be used as an absorber for the recovery of acetylene and sulfur dioxide, synthetic fiber modifiers, antifreeze agents, and capacitive media, brake oil, and rare metals. Extraction agents and so on.
3, as an analytical reagent and gas chromatography fixed liquid, also used as a solvent for ultraviolet spectroscopy
4, transdermal accelerator. Dimethyl sulfoxide is one of the earliest percutaneous penetration accelerators, and the proosmosis property may be related to its solvent properties. Dimethyl sulfoxide can make the skin keratinocytes denaturation of protein; It can destroy the ordered arrangement of the lipid between the stratum corneum cells. The cuticle lipids and lipoproteins can be removed to enhance the osmosis of the drug. However, the use of high concentrations of dimethyl sulfoxide can cause erythema, blisters, and irreversible damage to the skin. The United States has banned. The common concentration is 30 % -50 %.
5, antifreeze. The freezing point of pure dimethyl sulfoxide is 18. 45 °C, 40 % water-containing dimethyl sulfoxide -60 °C is not frozen, and dimethyl sulfoxide is exothermic when mixed with water and snow. Therefore, it is convenient to make automobile antifreeze, brake oil and hydraulic liquid components. Ethylene glycol antifreeze is no longer suitable at temperatures above -40 °C, and has a lower boiling point than dimethyl sulfoxide, is toxic, and is easily resistant to production. Dimethyl sulfoxide antifreeze is used in automobiles and Chariots in the northern cold areas and can be supplemented with snow water at any time. Dimethyl sulfoxide is also used in antifreeze, coating, various latex antifreeze, gasoline, aviation coal antifreeze, bone marrow, blood, organ low temperature preservation antifreeze.