Dimethyl sulfate
Names | |
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Preferred IUPAC name
Dimethyl sulfate | |
Other names
Dimethyl sulphate; Sulfuric acid dimethyl ester; Me2SO4; DMSO4; Dimethyl ester of sulfuric acid; Methyl sulfate, di-
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Identifiers | |
3D model (
JSmol ) |
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ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard
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100.000.963 |
KEGG | |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
C2H6O4S | |
Molar mass | 126.13 g/mol |
Appearance | Colorless, oily liquid |
Odor | faint, onion-like[1] |
Density | 1.33 g/ml, liquid |
Melting point | −32 °C (−26 °F; 241 K) |
Boiling point | 188 °C (370 °F; 461 K) (decomposes) |
Reacts | |
Solubility | Methanol, dichloromethane, acetone |
Vapor pressure | 0.1 mmHg (20 °C)[1] |
−62.2×10−6 cm3/mol | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards
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Extremely toxic, contact hazard, inhalation hazard, corrosive, environmental hazard, carcinogenic, mutagenic |
GHS labelling: | |
Danger | |
H301, H314, H317, H330, H335, H341, H350 | |
NFPA 704 (fire diamond) | |
Flash point | 83 °C; 182 °F; 356 K[1] |
Lethal dose or concentration (LD, LC): | |
LC50 (median concentration)
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8.6 ppm (rat, 4 hr) 75 ppm (guinea pig, 20 min) 53 ppm (mouse) 32 ppm (guinea pig, 1 hr)[2] |
LCLo (lowest published)
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97 ppm (human, 10 min)[2] |
NIOSH (US health exposure limits): | |
PEL (Permissible)
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TWA 1 ppm (5 mg/m3) [skin][1] |
REL (Recommended)
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Ca TWA 0.1 ppm (0.5 mg/m3) [skin][1] |
IDLH (Immediate danger) |
Ca [7 ppm][1] |
Related compounds | |
Related compounds
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methyl triflate, dimethyl carbonate
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Dimethyl sulfate (DMS) is a
Me2SO4 is a colourless oily
History
Dimethyl sulfate was discovered in the early 19th century in an impure form.[3] J. P. Claesson later extensively studied its preparation.[4][5]
It was investigated as a candidate for possible use in chemical warfare in
Production
Dimethyl sulfate can be synthesized in the laboratory by several methods,[9] the simplest being the esterification of sulfuric acid with methanol:[clarification needed]
- 2 CH3OH + H2SO4 → (CH3)2SO4 + 2 H2O
At higher temperatures, dimethyl sulfate decomposes.
The reaction of methyl nitrite and methyl chlorosulfonate also results in dimethyl sulfate:[5]
- CH3ONO + (CH3)OSO2Cl → (CH3)2SO4 + NOCl
Dimethyl sulfate has been produced commercially since the 1920s. A common process is the continuous reaction of dimethyl ether with sulfur trioxide.[10]
- (CH3)2O + SO3 → (CH3)2SO4
Reactions and uses
Dimethyl sulfate is a reagent for the methylation of phenols, amines, and thiols. One methyl group is transferred more quickly than the second. Methyl transfer is assumed to occur via an SN2 reaction. Compared to other methylating agents, dimethyl sulfate is preferred by the industry because of its low cost and high reactivity.
Methylation at oxygen
Commonly Me2SO4 is employed to methylate phenols. Some simple
- 2 (CH3)3COH + (CH3O)2SO2 → 2 (CH3)3COCH3 + H2SO4
Alkoxide salts are rapidly methylated to form methyl ethers:[11]
- RO−Na+ + (CH3O)2SO2 → ROCH3 + Na(CH3)SO4
The methylation of sugars is called Haworth methylation.[12] The methylation of ketones is called the Lavergne reaction.
Methylation at amine nitrogen
Me2SO4 is used to prepare both
- C6H5CH=NC4H9 + (CH3O)2SO2 → C6H5CH=N+(CH3)C4H9 + CH3OSO−3
Quaternized fatty ammonium compounds are used as a surfactant or fabric softener. Methylation to create a tertiary amine is illustrated as:[11]
- CH3(C6H4)NH2 + (CH3O)2SO2 (in NaHCO3 aq) → CH3(C6H4)N(CH3)2 + Na(CH3)SO4
Methylation at sulfur
Similar to the methylation of alcohols,
- RS−Na+ + (CH3O)2SO2 → RSCH3 + Na(CH3)SO4
An example is:[13]
- p-CH3C6H4SO2Na + (CH3O)2SO2 → p-CH3C6H4SO2CH3 + Na(CH3)SO4
This method has been used to prepare thioesters from thiocarboxylic acids:
- RC(O)SH + (CH3O)2SO2 → RC(O)S(CH3) + HOSO3CH3
Reactions with nucleic acids
Dimethyl sulfate (DMS) is used to determine the secondary structure of RNA. At neutral pH, DMS methylates unpaired adenine and cytosine residues at their canonical Watson–Crick faces, but it cannot methylate base-paired nucleotides. Using the method known as DMS-MaPseq,[14] RNA is incubated with DMS to methylate unpaired bases. Then the RNA is reverse-transcribed; the reverse transcriptase frequently adds an incorrect DNA base when it encounters a methylated RNA base. These mutations can be detected via sequencing, and the RNA is inferred to be single-stranded at bases with above-background mutation rates.
Dimethyl sulfate can effect the base-specific cleavage of DNA by attacking the
Alternatives
Although dimethyl sulfate is highly effective and affordable, its toxicity has encouraged the use of other methylating reagents.
Safety
Dimethyl sulfate is
One hypothesis regarding the apparently mysterious 1994
References
- ^ a b c d e f NIOSH Pocket Guide to Chemical Hazards. "#0229". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b "Dimethyl sulfate". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ Dumas, J.; Péligot, E. (1835). "Mémoire sur l'esprit de bois et sur les divers composés ethérés qui en proviennent" [Memoir on spirit of wood [i.e., methanol] and on various ethereal compounds that come from it]. Annales de Chimie et de Physique. 2nd series (in French). 58: 5–74.
- .
- ^ LCCN 44001248.
- ^ "Dimethyl Sulfate 77-78-1". EPA.
- ^ "Poison Facts: Low Chemicals: Dimethyl Sulfate". The University of Kansas Hospital.
- ^ Sartori, Mario (1939). The War Gases. D. Van Nostrand. pp. 262, 266.
- LCCN 64010030.
- ^ US Department of Health and Human Services. 2011.
- ^ a b c "Dupont product information". Archived from the original on 2008-11-19. Retrieved 2006-05-08.
- .
- ^ ISBN 9780471258759.
- PMID 27819661.
- ISBN 978-0024181701.
- PMID 11784197.
- ^ PMID 16299199.
- ^ "Material Safety Data Sheet - Dimethyl sulfate MSDS". ScienceLab. Archived from the original on 2012-04-06. Retrieved 2011-10-02.
- ^ ICSC
- ^ "What's the story on the "toxic lady"?". The Straight Dope. 1996-03-22. Retrieved 2024-01-15.
- PMID 9248041.