Dimethyl sulfate
[CAS# 77-78-1]

Identification

• Classification: Organic raw materials >> Inorganic acid ester
• Name: Dimethyl sulfate
• Synonyms: Methyl sulfate
• Molecular Formula: C₂H₆O₄S
• Molecular Weight: 126.13
• CAS Registry Number: 77-78-1
• EC Number: 201-058-1
• SMILES: COS(=O)(=O)OC

Properties

• Density: 1.3±0.1 g/cm³, Calc.^*, 1.333 g/mL (Expl.)
• Melting point: -32 ºC (Expl.)
• Index of Refraction: 1.41, Calc.^*, 1.386 (Expl.)
• Boiling Point: 188.0 ºC (760 mmHg), Calc.^*, 188 ºC (Expl.)
• Flash Point: 83.3 ºC, Calc.^*, 83.3 ºC (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07;GHS08 Danger
• Hazard Statements: H301-H310-H314-H317-H318-H319-H330-H335-H341-H350
• Precautionary Statements: P203-P260-P261-P262-P264-P264+P265-P270-P271-P272-P280-P284-P301+P316-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P351+P338-P305+P354+P338-P316-P317-P318-P319-P320-P321-P330-P333+P317-P337+P317-P361+P364-P362+P364-P363-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	3	H301
Germ cell mutagenicity	Muta.	2	H341
Carcinogenicity	Carc.	1B	H350
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	1	H330
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	2	H330
Acute toxicity	Acute Tox.	2	H310
Eye irritation	Eye Irrit.	2	H319
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1A	H314
Germ cell mutagenicity	Muta.	2	H340
Acute toxicity	Acute Tox.	2	H331
Carcinogenicity	Carc.	1A	H350

• Transport Information: UN 1595

Discovory and Applicatios

Dimethyl sulfate (DMS), with the chemical formula (CH3O)2SO2, is a highly reactive and toxic chemical compound commonly used in organic synthesis. It consists of two methoxy groups (-OCH3) attached to a central sulfur atom, which is doubly bonded to an oxygen atom. This compound is primarily known for its methylating properties and is widely utilized in the chemical and pharmaceutical industries. Its discovery and applications have made it a versatile reagent in synthetic chemistry, though its toxic nature necessitates caution in its handling and use.

The synthesis of dimethyl sulfate was first reported in the early 19th century, and its structure and reactivity were progressively understood over time. The compound was originally synthesized by the reaction of methyl alcohol with sulfuric acid, producing dimethyl sulfate and water. Over the years, its chemical behavior, particularly its ability to introduce methyl groups into molecules, was explored, making it a valuable tool in organic chemistry.

Dimethyl sulfate is a potent methylating agent, meaning it is capable of transferring a methyl group (-CH3) to other molecules. This reactivity is one of the reasons for its widespread use in organic synthesis. It is commonly used in the preparation of methylated compounds, such as methyl ethers and methyl esters, as well as in the methylation of nucleic acids and proteins. In this role, it is used to modify or enhance the properties of various organic molecules, making it an essential tool in chemical research.

One of the most important applications of dimethyl sulfate is in the pharmaceutical industry, where it is used in the synthesis of a variety of compounds. It is involved in the preparation of drugs, particularly in the methylation of pharmaceutical intermediates. For example, dimethyl sulfate is used in the production of certain alkaloid drugs, where the methylation of nitrogen-containing compounds enhances their biological activity or stability. It has also been used in the synthesis of several important antibiotics and other bioactive molecules.

In addition to its pharmaceutical uses, dimethyl sulfate plays a significant role in the production of pesticides and herbicides. Its ability to methylate nitrogen atoms in chemical structures makes it useful in the modification of active ingredients in pesticides, contributing to their stability and efficacy. The use of dimethyl sulfate in agricultural chemicals extends its importance beyond pharmaceuticals into the field of agrochemicals.

Dimethyl sulfate is also used in the preparation of specialty chemicals, such as dyes, pigments, and surfactants. Its methylating properties are valuable in modifying the chemical structure of these compounds, improving their solubility, stability, and performance in various applications. In the case of surfactants, dimethyl sulfate helps in the production of nonionic surfactants, which are used in detergents and cleaning products.

Despite its utility in these applications, dimethyl sulfate is a highly toxic and hazardous substance. It is classified as a carcinogen, and exposure to its vapors or contact with the skin can cause severe irritation or injury. Its toxicological effects have led to strict regulations governing its handling, storage, and disposal. Protective measures, such as working in well-ventilated areas and using proper personal protective equipment, are essential when working with dimethyl sulfate.

In summary, dimethyl sulfate is an important and versatile chemical compound with a range of applications in organic synthesis, pharmaceuticals, agrochemicals, and specialty chemical production. Its ability to methylate a variety of compounds makes it a valuable tool in both industrial and research settings. However, due to its toxic nature, its use is highly regulated, and safety precautions must be followed to minimize exposure and risk.

References

2024. Mechanistic Investigation of Dimethyl Carbonate Synthesis Over Palladium Chloride Catalyst. Catalysis Letters, 154(12).
DOI: 10.1007/s10562-024-04855-z

2024. Determination of Residual Dimethyl Sulfate in Cephalosporin Using HS-SPME/GC-MS. Journal of Chromatographic Science, 62(9).
DOI: 10.1093/chromsci/bmae054

2024. CeO2/β composite catalysts in dimethyl carbonate synthesis from CO2: effect of preparation method on surface oxygen species. Reaction Kinetics, Mechanisms and Catalysis, 137(5).
DOI: 10.1007/s11144-024-02755-2