Methyl sulfoxide, DMSO, FEMA 3875, DIMETHYLIS SULFOXIDUM, Dimethyl sulfoxide Sulfinylbis, 67-68-5 

Methyl sulfoxide, DMSO, FEMA 3875, DIMETHYLIS SULFOXIDUM, Dimethyl sulfoxide Sulfinylbis, 67-68-5 

Methyl sulfoxide

CAS: 67-68-5

Molecular Formula: C2H6OS

Names and Identifiers

Physico-chemical Properties

Risk and Safety

Hazard Symbols	Xi - Irritant
Risk Codes	36/37/38 - Irritating to eyes, respiratory system and skin.
Safety Description	S24/25 - Avoid contact with skin and eyes. S37/39 - Wear suitable gloves and eye/face protection S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. S23 - Do not breathe vapour.
UN IDs	NA 1993 / PGIII
WGK Germany	1
RTECS	PV6210000
FLUKA BRAND F CODES	3
TSCA	Yes
HS Code	29309070
Toxicity	LD50 orally in rats: 17.9 ml/kg (Bartsch)

Upstream Downstream Industry

Nature

A colorless transparent liquid at room temperature. Strong hygroscopicity. Soluble in water, ethanol, acetone, ether and chloroform, is a strong polar inert solvent. Flammable in case of open flame and high heat. Toxic sulfide smoke is produced by thermal decomposition. It can react with acid chloride, trichlorosilane, phosphorus trichloride and other halides.

Preparation Method

dimethyl sulfide was prepared by using methanol and carbon disulfide as raw materials, and then dimethyl sulfoxide was prepared by oxidation and purification of dimethyl sulfide.

Standard

• This product can be prepared by air oxidation of dimethyl sulfide in the presence of nitrogen oxide; It can also be prepared from the by-products of pulp manufacturing.
• This product shall not be less than 99.5% calculated as anhydrous.

Trait

This product is a colorless liquid; Odorless or almost odorless; There is hygroscopicity.
This product and water, ethanol or ether can be freely miscible, insoluble in alkanes.

freezing point

The freezing point of this product (General 0613) is 17. 0~18. 3°C.

refractive index

The refractive index of this product (General 0622) is 1. 478~479.

relative density

The relative density of this product (General 0601) is 1. 095~105.

 Introduction

Nearly odorless, slightly bitter. It has a strong polarity and is hygroscopic and soluble in water, ethanol, acetone, ether, benzene and chloroform, but insoluble in aliphatic hydrocarbons other than acetylene. It can dissolve ethylene oxide, benzoic acid, camphor, sugar, grease, etc., and can also dissolve sulfur dioxide, nitrogen dioxide, calcium chloride, and sodium nitrate.

Use

methyl sulfoxide is an extremely important aprotic polar solvent that is soluble in both water and organic solvents. It is widely used as solvent and reaction reagent with high selective extraction ability. It can be used as an extraction solvent for separating alkanes from aromatic hydrocarbons; As a synthetic solvent for polyamides, fluorochloroaniline, polyimides and polysulfone resins; And as a solvent for acetylene, aromatic hydrocarbons, sulfur dioxide and other gases. DMSO has anti-inflammatory, analgesic, diuretic, sedative and other effects. In the pharmaceutical industry, dimethyl sulfoxide can also be directly used as the raw material and carrier of some drugs. It can also be used as a capacitance medium, an anti-freezing agent, a brake oil, a rare metal extraction agent, etc.

Differential diagnosis

1. take 5ml of this product, put it in a test tube, add 50mg of nickel chloride, shake to dissolve, the solution is yellow-green, put 50°C water bath to heat, the solution is green or blue-green, let cool, the solution was yellow-green in color.
2. The infrared absorption spectrum of this product should be consistent with that of the reference product (General rule 0402).

Safety

rat oral LDso: 17.9 ml/kg. Harmful to the body after inhalation, ingestion or absorption through the skin. It has a stimulating effect on the eyes, skin, mucous membranes and upper respiratory tract. Store in a cool, ventilated warehouse. Keep away from fire and heat source. It should be stored separately from oxidants, reductants, halides and acids, and mixed storage should not be avoided.

Exam

acidity

take this product 50. 0g, add 100ml of water to dissolve, add phenolphthalein indicator solution 0. lm l, with sodium hydroxide titration solution (0. Olmol/L) titration until the solution is pink, consumption of sodium hydroxide titration solution (0. 0 lm o l/L) 5. 0ml.

absorbance

take an appropriate amount of this product, dry nitrogen for 15 minutes, take water as a blank, according to ultraviolet-visible spectrophotometry (General rule 0401), immediately determine, the absorbance at a wavelength of 275nm should not be greater than 0. 30; The ratio of the absorbance at 285nm and 295mn wavelengths to the absorbance at 275ntn wavelengths should not exceed 0 .6 5 and 0.4 5; In the wavelength range of 270 ~ 350nm, there shall be no maximum absorption peak.

the precision amount of potassium hydroxide darkening material

take 25ml of this product, put it in 50ml measuring flask, add water 0 .5M l with potassium hydroxide l .O g, tampon, heat on the water bath for 20 minutes, cool, put the solution in lc m absorption cell, take water as blank solution, UV-visible spectrophotometry (General rule 0401>, measured at a wavelength of 350nm absorbance, not greater than 0.023.

moisture

take this product, according to the moisture determination method (General rule 0832 first method 1) determination, containing water not more than 0 .2%.

Related substances

take this product, precision weighing, with internal standard solution (0.025% diphenylmethane acetone solution) diluted into 50% solution, as the test solution; Take the appropriate amount of test solution, add the internal standard solution diluted to 0.050% solution, as a control solution; Take the appropriate amount of dimethyl sulfone control, ^ cimetidine, diluted with the above internal standard solution to make 0.050% solution, as dimethyl sulfone control solution; according to the test of gas chromatography (General rule 0521), with 10% polyethylene glycol 2 0m as stationary liquid, column temperature 150C, F ID detector; The number of theoretical plates shall not be less than 1500 based on the peak of dimethyl sulfone, the separation degree between the dimethyl sulfone peak and the internal standard peak should be greater than 2. 0. The test solution, the control solution and the dimethyl sulfone reference solution were injected with 2 ^ 1 respectively into the human gas chromatograph, and the chromatograms were recorded. If the sample solution shows the peak of dimethyl sulfone, the ratio of the peak area of dimethyl sulfone to the peak area of diphenyl methane shall not be greater than the ratio of the peak area of dimethyl sulfone to the peak area of diphenyl methane in the reference solution of dimethyl sulfone (0 .1%). The ratio of the total Peak area of all impurities in the Test Solution (except the main peak and the internal standard peak) to the peak area of diphenylmethane shall not be greater than the ratio of the peak area of dimethyl sulfoxide and diphenylmethane in the control solution (0. 1%).

Non-volatile residue

take 100g of this product, weigh it accurately, place it in a 105C dry evaporation dish with constant weight, and slowly evaporate to dryness (without boiling) on the electric heating plate built in the fume hood, it was dried at 105°C for 3 hours and weighed. The residue should not exceed 0.01%.

Category

pharmaceutical excipients, absorption enhancers, solvents and antifreeze (for external use only).

Introduction

Overview    

Dimethyl sulfoxide (referred to as DMSO) is a sulfur-containing organic compound, English dimethy1 sulfoxide, molecular formula (CH3)2SO, colorless and odorless transparent liquid at room temperature, flammable liquid with hygroscopicity, both high polarity, high boiling point, non-Proton, water miscible characteristics, very low toxicity, good thermal stability, not mixed with alkanes, soluble in water, ethanol, propanol, ether, benzene and chloroform and most organic matter, known as the "universal solvent". Is commonly used in organic solvents, one of the strongest solubility. It dissolves most organic compounds, including carbohydrates, polymers, peptides, and many inorganic salts and gases. It can dissolve 50-60% by weight of its own solute (other general solvents can only dissolve 10-20%), so it is very important in sample management and high-speed drug screening. Under certain conditions, an explosive reaction occurs when dimethyl sulfoxide is contacted with the acid chloride. Dimethyl sulfoxide is widely used as solvent and reaction reagent, especially as processing solvent and spinning solvent in acrylonitrile polymerization, as Polyurethane synthesis and spinning solvent, as synthetic solvent of polyamide, polyimide and Polysulfone Resin, and aromatic hydrocarbon, butadiene extraction solvent and solvent for synthesis of chlorofluoroaniline. In addition, In the pharmaceutical industry, dimethyl sulfoxide is also directly used as a raw material and carrier for some drugs. Dimethyl sulfoxide itself has anti-inflammatory and analgesic, diuretic, sedative and other effects, also known as the "spirit", often as the active component of analgesic drugs added to the drug. It has the special property of being very easy to penetrate the skin, which causes the user to feel like an oyster-like taste. A solution of sodium cyanide in dimethyl sulfoxide can cause cyanide poisoning via skin contact. And the toxicity of dimethyl sulfoxide itself is low. Dimethyl sulfoxide (DMSO) is widely used as an extractant by chemical and pharmaceutical enterprises. However, due to the high boiling point of DMSO, the operation temperature is too high, which causes the coking of the material and affects the recovery of dimethyl sulfoxide and the cleaning of the equipment, it also increases energy consumption. Therefore, the recovery of dimethyl sulfoxide has become a bottleneck for its further widespread use as an extractant. Dimethyl sulfoxide is a common aprotic organic solvent used to dissolve polar and non-polar compounds. Deuterated form DMSO-d6 (D479382), which is mainly used for nuclear magnetic resonance studies, is easy to identify because of its ability to dissolve most analytes.

purification and water removal method    

dimethyl sulfoxide can be mixed with water and can be dried by long-term storage of molecular sieves. Distillation was then performed under reduced pressure to collect a 76 °c/1600pa (12mmHg) fraction. Distillation, the temperature should not be higher than 90 deg C, otherwise it will occur disproportionation reaction to produce dimethyl sulfone and dimethyl sulfide. Calcium oxide, calcium hydride, barium oxide or anhydrous barium sulfate may also be used for drying, followed by distillation under reduced pressure. It can also be purified by partial crystallization. Attention should be paid to the possibility of explosion when dimethyl sulfoxide is mixed with certain substances, such as sodium hydride, periodic acid or magnesium perchlorate.

identification and detection methods    

identification - take 1.5 of this product, slowly drop it into the cooled 2.5ml of hydroiodic acid, and quickly filter it, after drying under reduced pressure, the resulting residue was an unstable, dark purple crystalline solid with unpleasant odor, dissolved in chloroform and gave a red solution. [Inspection] the appropriate amount of light absorption of this product, through the flow of dry nitrogen for 15 minutes, immediately placed in the 1cm absorption tank, with water as blank, according to The spectrophotometric method (Chinese Pharmacopoeia 1990edition, Part II, Appendix 24), the absorbance shall not be greater than 0.30 at the wavelength of 275nm; The absorbance shall be measured at the wavelengths of 285nm and 295nm respectively, and the ratio of the absorbance to that at 275nm, respectively shall not be greater than 0.65 and 0.45, and in the range of 270 ~ 350nm, shall not have the maximum absorption peak. Water shall not exceed 0.2% (Appendix 55 pages of volume II of Chinese Pharmacopoeia 1990edition). Dimethyl sulfone to take diphenyl methane, made of 0.025% acetone solution, as the internal standard solution; Precision weighing the right amount of dimethyl sulfone, with the internal standard solution diluted into 0.050% solution, as a control solution, precision weighing, with the internal standard solution diluted to 50% of the solution, as the test solution. According to the method of gas chromatography (method 31 (3) in Appendix 2 of Chinese Pharmacopoeia 10% edition), polyethylene glycol 20m with coating concentration of was used as stationary liquid, (The number of theoretical plates calculated according to dimethyl sulfone should be greater than 1500, and the separation degree of dimethyl sulfone peak and internal standard peak should be greater than 2), the peak area ratio of dimethyl sulfone and diphenyl methane in the test solution shall not be greater than that in the control solution at the column temperature of 150 ℃.

toxicity    GRAS(FEMA).

usage limit    FEMA(mg/kg) baked goods, non-alcoholic beverages, breakfast cereals, cold drinks, sauces, meat products, dairy products, soft candy, soup, sweet sauce, 0.1~5.0; Flavoring spices 100~1000.

recovery method    

when dimethyl sulfoxide (DMSO) is used as a solvent, recovery must be considered to reduce production costs. DMSO can be easily dissolved in water, benzene, toluene to produce the characteristics of the association, the general use of extraction and back extraction method to separate from other impurities, and then vacuum distillation to obtain a pure product. For example, the mixture of DMSO and inorganic salts is extracted from the mixture with toluene, and then water is added to the extracted solution to back extract DMSO, and the obtained DMSO aqueous solution is distilled under the residual pressure of (1.33~2.00)× 103Pa, A DMSO content of more than 99% was obtained. During the extraction of aromatic hydrocarbons, aromatic hydrocarbons are extracted from the reformate by positive extraction, and then water is added to the extracted liquid for back extraction to obtain aqueous DMSO, and then pure DMSO is obtained by distillation under reduced pressure. In addition, there is the use of potassium dihydrogen phosphate salting-out method, with methanol, ethanol extraction recovery method, can be used under specific conditions. Small Batch users are not convenient for recycling can be collectively entrusted to the production plant recycling. The basic way of DMSO recovery is vacuum distillation, but to meet the two conditions, the first is the temperature must be below 120 degrees, otherwise there will be safety problems, and reduce the recovery rate. Another problem is the PH value of the system, the more appropriate value is PH = 8, where there are equipment safety issues and DMSO decomposition conditions are suitable for the above PH value. I use the tower is carbon steel, 7-8 trays, reflux ratio of 3-2 can be. Generally can reach 98-99% content, the device is 2000L. The effect is very good. The method for recovering dimethyl sulfoxide in ketoconazole production by semi-continuous vacuum distillation is as follows:(1) feed the raw material into the distillation column kettle, and when the liquid level reaches 1/3, start heating;(2) when the top temperature of the distillation column reaches 60 ℃, open the internal reflux cooler and vacuum system;(3) when the vacuum degree reaches 0.1~0.15 × 10 [4]Pa, control the top discharge of the distillation column: when the top temperature reaches 65 ℃, the top discharge is semi-finished; When the top temperature reaches 80 ℃, and found that the top temperature rises rapidly, the top discharge is dimethyl sulfoxide;(4) until the temperature reaches 110 ℃; vent and stop heating;(5) discharge the residual liquid in the tower kettle.

Use    

for aromatic extraction, resin and dye reaction medium, acrylic polymerization, spinning solvent
can be used as organic solvent, reaction medium and organic synthesis intermediates. Very wide range of uses. This product has high selective extraction ability, used as polymerization and condensation solvent of acrylic resin and Polysulfone Resin, polymerization solvent of polyacrylonitrile and acetic acid fiber, extraction solvent for separation of alkane and aromatic hydrocarbon, aromatic hydrocarbon, butadiene extraction, acrylic spinning, plastic solvents and organic synthetic dyes, pharmaceutical and other industrial reaction media. In medicine, dimethyl sulfoxide has anti-inflammatory and analgesic effect, strong penetration of the skin, which can dissolve some drugs, so that this kind of drug to the human body to achieve the purpose of treatment. Using this carrier characteristic of dimethyl sulfoxide, it can also be used as an additive for pesticides. Adding a small amount of dimethyl sulfoxide in some pesticides can help the pesticide penetrate into the plant to improve the efficacy. Dimethyl sulfoxide can also be used as a dyeing solvent, dye removal agent and dyeing carrier for synthetic fibers, and can also be used as an absorbent for recovering acetylene and sulfur dioxide, a modifier for synthetic fibers, an anti-freezing agent, a capacitive medium, brake oil, rare metal extractants, etc.
used as analytical reagent and gas chromatography stationary liquid, also used as solvent in UV spectrum analysis
used as organic solvent, reaction medium and organic synthesis intermediate. Very wide range of uses. With high selective extraction ability, it is used as polymerization and condensation solvent of acrylic resin and Polysulfone Resin, polymerization and spinning solvent of polyacrylonitrile and acetic acid fiber, extraction solvent for separation of alkane and aromatic hydrocarbon, aromatic hydrocarbon, butadiene extraction, acrylic spinning, plastic solvents and organic synthetic dyes, pharmaceutical and other industrial reaction media. Medicine, anti-inflammatory analgesic effect, strong penetration of the skin.
production method    

dimethyl sulfoxide is generally prepared by oxidation of dimethyl sulfide, thus, there are different production processes. 
1. Methanol carbon disulfide methyl alcohol and carbon disulfide as raw materials, with γ-Al2O3 as Catalyst, the first synthesis of dimethyl sulfide, and then with nitrogen dioxide (or nitric acid) oxidation of dimethyl sulfoxide. 
2. Hydrogen peroxide method with acetone as buffer medium, the reaction of dimethyl sulfide and hydrogen peroxide. This method is not suitable for large-scale production because of its high cost. 
3. The nitrogen dioxide method uses methanol and hydrogen sulfide to generate dimethyl sulfide under the action of γ-alumina; Sulfuric acid reacts with sodium nitrite to generate nitrogen dioxide; Dimethyl sulfide is then oxidized with nitrogen dioxide at 60-80 ℃ to generate crude dimethyl sulfoxide, there is also a direct use of oxygen oxidation, the same formation of crude dimethyl sulfoxide, and then vacuum distillation, refined dimethyl sulfoxide products. This method is a more advanced production method. Dimethyl sulfate method with dimethyl sulfate and sodium sulfide reaction, dimethyl sulfide; Sulfuric acid and sodium nitrite reaction to generate nitrogen dioxide; Dimethyl sulfide and nitrogen dioxide oxidation of crude dimethyl sulfoxide, and then treated by neutralization, distillation to dimethyl sulfoxide. In addition, dimethyl sulfoxide was produced from dimethyl sulfide by anodic oxidation.

Storage

sealed, stored in a cool, dry place.

Introduction

Nature:
1. Appearance: Colorless liquid.
2. Solubility: It has high solubility and can dissolve various organic and inorganic substances.
3. Characteristics: It has anti-inflammatory, antibacterial, and tissue healing promoting effects.

Usage:
1. Chemical experiment: used to dissolve compounds that are difficult to dissolve in other solvents.
2. Industrial application: used in organic synthesis.

Method:
DMSO is usually obtained by oxidizing sulfite hydrates, and the specific steps are as follows:
React sulfuric acid hydrate with diethyl sulfur dioxide
Distillation to obtain dimethyl sulfoxide product

Security information:
1. Has certain toxicity, avoid contact with skin and inhalation of gases.
2. As a flammable liquid, it is necessary to stay away from open flames and high temperatures.
3. Be careful when using to avoid accidental ingestion and eye contact.
4. Long term or excessive exposure may cause skin allergic reactions, and excessive exposure should be avoided.

Introduction

1. Solvent: DMSO is an excellent solvent, capable of dissolving a wide range of organic and inorganic compounds. It can dissolve both polar and non-polar substances, making it versatile in various applications.
2. Hygroscopic: DMSO is hygroscopic, meaning it readily absorbs water from the atmosphere. This property can be advantageous in certain processes, but also requires proper storage and handling to prevent contamination.
3. High boiling point: DMSO has a high boiling point of 189°C (372°F), allowing it to be used in high-temperature applications.
4. Low toxicity: DMSO is considered to have low toxicity in most applications. However, it can enhance the absorption of certain substances through the skin, making appropriate precautions necessary.
5. Medical and pharmaceutical applications: DMSO is used in the pharmaceutical industry as a solvent and as a carrier for drug delivery. It can penetrate through the skin and has anti-inflammatory and analgesic properties, which make it suitable for use in topical treatments.
6. Industrial and laboratory use: DMSO finds utility in various industrial processes, such as in the production of polymers, as a reaction solvent in organic synthesis, and as a cryoprotectant for cell preservation.
7. Research and scientific studies: DMSO is commonly used in research laboratories for different purposes, including cryopreservation of cells, as a solvent for chemical reactions, and as a cryoprotectant in protein structure studies.