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Material Safety Data Sheet(MSDS)

Questions And Answer

• Overview

  Dimethyl sulfoxide (abbreviated DMSO) is a sulfur-containing organic compound; molecule formula: (CH3) 2SO; It exhibits as colorless, odorless, hygroscopic and flammable transparent liquid at room temperature. It has both high polarity as well as high-boiling point. It also has aprotic and water-miscible characteristics. It has low toxicity, good thermal stability, and is not miscible with paraffin. It is soluble in water, ethanol, propanol, ether, benzene and chloroform and many other kinds of organic substance and is called as the "universal solvent." It is a common organic solvent which has the strongest dissolving ability. It can dissolve most the organic compounds including carbohydrates, polymers, peptides, as well as many inorganic salts and gases. It can dissolve certain amount solute whose weight is equals to 50-60% of itself (other common solvents usually only dissolve 10-20%), so it is very important in the sample management as well as high-speed screening of drugs. Under certain conditions, contact between dimethyl sulfoxide and chloride can even lead to explosive reaction.
  dimethyl sulfoxide is widely used as solvents and reagents, particularly as the processing reagent and spinning solvent at the reaction of acrylonitrile polymerization used for polyurethane synthesis and the spinning solvent. It can also be used as the synthetic solvent for polyamide, polyimide and polysulfone resin as well as the extraction solvents for aromatic hydrocarbon and butadiene extraction solvents and solvents for synthesizing chlorofluoroaniline. In addition, dimethyl sulfoxide can also be directly used as the raw material or carrier of some drug in the pharmaceutical industry. dimethyl sulfoxide itself has various effects such as anti-inflammatory, analgesic, diuretic, and sedative, and thus also being known as "panacea" which is usually as the active ingredient of analgesic medication being added to the drug. It also has special properties of easy penetration through the skin, resulting in personnel feeling of oyster-like flavor. The dimethyl sulfoxide solution of sodium cyanide can cause cyanide poisoning through skin contact while dimethyl sulfoxide itself has a relative low toxicity. dimethyl sulfoxide is widely applied as the extraction agent in a lot of chemical and pharmaceutical companies. However, because of its higher boiling point, it causes very high operating temperatures and further causes the coking of materials, thus affecting the recycling of dimethyl sulfoxide and further cleaning of the equipments as well as resulting in increased energy consumption. Therefore, the recycling of dimethyl sulfoxide has become a bottleneck as its further wide application as extraction agent.
  The above information is edited by the Chemicalbook of Dai Xiongfeng. ;

• Method of purification and water removal

  dimethyl sulfoxide can be mixed with water and can be placed for long term storage and drying through molecular sieve. Further apply it to vacuum distillation and collect the fraction of 76 °C/1600Pa (12mmHg). Upon distillation, keep the temperatures at below 90 °C; otherwise it will result in disproportionation reaction which generates dimethyl sulfone and dimethyl sulfide. It may also be dried through calcium oxide, calcium hydroxide, barium oxide and barium sulfates and then distilled under reduced pressure. It may also be purified through partially crystallization. It can lead to explosion when mixing the dimethyl sulfoxide with certain substance such as sodium hydride, periodic acid or magnesium perchlorate, and thus should be paid attention. ;

• Identification and detection methods

  [Identification] Take 1.5 mL of this product and add to it slowly of 2.5 mL cooled hydroiodic acid drop wise; rapidly filter it and dry it under reduced pressure with the residue being unstable dark purple crystalline solid which has an unpleasant smell. Dissolving it in chloroform will form a red solution.
  [Check] Optical absorption, take certain amount of this product, pour through the stream of dry nitrogen for 15 minutes and immediately place it in 1cm absorption cuvette with water as a blank. Measure the absorbance of 275 nm according to spectrophotometric method (Chinese Pharmacopoeia 1990 edition of Appendix page 24) with a value being not higher than 0.30; and then further measure absorbance at wavelength of 285nm and 295nm with its ratio over that of the absorbance of 275nm being not greater than 0.65 and 0.45, respectively. Also note that, there should be no maximal absorption in the 270~350nm range. The water content should not exceed 0.2% (Chinese Pharmacopoeia 1990 edition of Appendix 55). Dimethyl sulfone take diphenyl methane to make a 0.025% acetone solution as the internal standard solution; accurately weigh appropriate amount of dimethyl sulfoxide and dilute to 0.050% solution of internal standard solution as the control solution; in addition, accurately weigh certain amount of this product and dilute to 50% solution with internal standard solution as the test solution. According to gas chromatography protocol (Chinese Pharmacopoeia 1990 edition, second volume, appendix page 31(3)), use 20 mM of 10% (coating concentration) polyethylene glycol as the fixer liquid; (the theoretical plate number calculated from dimethyl should be greater than 1500, and the separation degree of dimethyl sulfoxide peak and the internal standard peak should be greater than 2). The measured ratio of dimethyl sulfone peak area and diphenyl methane peak area of the sample solution at a column temperature of 150 °C should not be greater than that of the control solution. ;

• Reference quality standards

  For external use-DMSO quality of technical indicators
  Content, GC,%, ≥ 99.9 GB/2307-1986) Gas Chromatography
  IR identification, qualified EP
  Chemical identification, qualified EP
  Crystallization point, °C ≥ 18.3 GB/T7533-1993
  The refractive index of 1.478-1.479 GB/T6488-1986
  Moisture,%, KF, ≤ 0.2 GB/T6283-1986
  UV extinction values, 275nm ≤ 0.3 GB 9721-1988
  285nm ≤ 0.2
  295nm ≤ 0.2
  Heavy metals, PPm ≤ 10 GB/7532-1987
  Specific gravity (20 ℃), 1.100-1.104 GB/4472-1984
  Acidic value (0.1N/ml NaOH/50g), ≤ 5.0 GB/9736-1988
  Packaging: PE plastic bucket Anhydrous-Technical index of DMSO quality
  Content (DMSO), GC%, ≥ 99.9 GB/2307---1986) Gas Chromatography
  Crystal point, °C, ≥ 18.35 GB/T7533-1993
  Acidic value mgKOH/g, ≤ 0.001 GB/T9736-1988
  Refractive index (20 °C), 1.478-1.479 GB/6488---1986
  Moisture,%, KF, ≤ 0.001 GB/6283--1986
  Evaporation residue, PPM, ≤ 5. GB/T3209----82
  Heavy metals,%, ≤ 10. GB/T7532----87
  Package: PE plastic bucket ;

• Toxicity

  GRAS (FEMA). ;

• Limited use

  FEMA (mg/kg) bakery products, non-alcoholic beverages, breakfast cereals, cold drinks, sauces, meat products, dairy products, soft candy, soups, sweet sauces; 0.1 to 5.0 in average; Spices: 100-1000. ;

• Recovery process

  We should take recycling into account when using DMSO as a solvent in order to reduce the production cost. We can take advantage of DMSO’s property of being easily soluble in water, benzene, and toluene to generate association complex to separate it from other impurities using ether extraction or reverse extraction, and further apply vacuum distillation to get pure product. For example: for the mixture between DMSO and the inorganic salt, use toluene to extract DMSO out, and then further add water to the extraction liquid for reverse extraction of DMSO. The resulting DMSO aqueous solution is subject to vacuum distillation at reduced pressure ((1.33~2.00) × 103Pa to obtain the DMSO of over 99%. Upon the extraction with arene, first extract out the arene from reformate; further add water to the extracted liquid for reverse extraction to obtain the aqueous DMSO. Further get the pure DMSO product through vacuum distillation. In addition, there are also some other methods such as salting out with potassium dihydrogen phosphate, recycling method via methanol, ethanol extraction which can be adopted under certain conditions. For user of small quantities which is not easy to recycle can pile them up and commit to the production plant for recycling together.
  The basic approach of DMSO recycling is through vacuum distillation with the requirement of two conditions, first, keep the temperature below 120 degrees, otherwise there will be security problems, and will also cause lower recovery. Another issue is the PH value of the system. An appropriate value is pH 8 which is suitable for both safety issue as well as the proper decomposition condition of DMSO. The tower I used is carbon steel with 7-8 trays and the reflux ratio being 3-2 which can generally reach 98-99% content. The device volume is 2000 L with a very good efficacy.
  Semi-continuous vacuum distillation method for recovering the DMSO in ketoconazole production is as follows: (1) pour the raw material into the distillation column reactor, start heating when the liquid level reaches 1/3; ( 2) when the temperature of the top of rectification column top temperature reached 60 °C, turn on the internal reflux cooler as well as the vacuum system; (3)When the degree of vacuum reaches 0.1~0.15 × 10 Pa ↑, control the top of the distillation column of yielding material: when the top temperature reached 65 °C, the top of the rectification column mainly produces the semi-finished material; when the top temperature reached 80 °C, and also there was rapid increase in temperature of the top, the yielding material in top is DMSO; (4) When the temperature reaches 110 °C, vent and stop heating; (5) release the residue in the tower kettle. ;

• Chemical Properties

  It is colorless liquid, and is hygroscopic. It is almost odorless with a bitter taste. It can be dissolved in water, ethanol, acetone, ether, benzene and chloroform. ;

• Uses

  1. It can be used for the extraction of arene, also as the reaction medium used for resins and dyes, and applied to acrylic polymerization and spinning solvent.
  2. It can be used as an organic solvent, reaction medium and the intermediates of organic synthesis. It is highly versatile. This product has a highly selective extraction capacity, and can be used as the polymerization and condensation solvent of acrylic resin and polysulfone resin, as the polymerization and spinning solvent of polyacrylonitrile and cellulose acetate, as the extraction solvent for separating alkanes and arenes, and as the reaction medium for the arenes, butadiene extraction, acrylic fiber, plastic solvents, organic and synthetic dyes, and pharmaceuticals industries. In the field of medicine, dimethyl sulfoxide has anti-inflammatory and analgesic effect with a strong capability of penetration through the skin, and thus being able to dissolve certain drugs and boost their penetration into the human body to achieve the therapeutic purposes. Taking this carrier property of dimethyl sulfoxide can make it be used as pesticide additives. Add a small amount of dimethyl sulfoxide in some pesticides can facilitate the penetration of pesticides into the plant in order to improve the efficacy. dimethyl sulfoxide can also be used as the dye solvent, dye removing agent, and dye carrier for the synthetic fibers. It can also be used as the absorbent of recycling acetylene and sulfur dioxide and also the modifiers of synthetic fiber, antifreeze agent and the capacitor dielectric, brake oil, and extractant of the rare metals.
  3. It can be used as analytic solvents and fixing agent of gas chromatography as well as the solvent for analyzing UV spectra. ;

• Production method

  dimethyl sulfoxide is generally made by using dimethyl sulfide oxidation method. They have different production processes due to the different oxidants and oxidation types. 1. Methanol carbon disulfide method; take carbon disulfide and methanol as raw materials and use γ-Al2O3 as the catalyst; first synthesize the dimethyl sulfide, then have oxidation reaction with nitrogen dioxide (or nitrate) to obtain dimethyl sulfoxide. 2. The hydrogen peroxide method: take acetone as the buffer medium to have dimethyl sulfide be reacted with hydrogen peroxide. This method of dimethyl sulfoxide synthesis has a relative high cost and thus is suitable for large-scale production. 3. The method of nitrogen dioxide: have methanol and hydrogen sulfide dimethyl sulfide reacted in the catalysis of γ-alumina to obtain dimethyl sulfide; have sulfate reacted with sodium nitrite to generate nitrogen dioxide; dimethyl sulfide has gas-liquid phase reaction with nitrogen dioxide at 60-80 °C to produce crude dimethyl sulfoxide. Sometimes people also use oxygen for direct oxidation which also generates the crude dimethyl sulfoxide. Then after vacuum distillation, refine to get the finished product of dimethyl sulfoxide. This method is a relative advanced production method. 4. Dimethyl sulfate method: apply dimethyl sulfate to react with sodium sulfide to obtain dimethyl sulfide; sulfate has reaction with sodium nitrite to generate nitrogen dioxide; dimethyl sulfide is oxidized with nitrogen dioxide to generate the crude dimethyl sulfoxide, and then undergo neutralization and distillation to obtain refined dimethyl sulfoxide product. In addition, the anodic oxidation method can also produce dimethyl sulfoxide via dimethyl sulfide. ;

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