Benzyl mercaptan

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Benzyl mercaptan
Skeletal formula
Ball-and-stick model
Identifiers
CAS number 100-53-8 YesY
PubChem 7509
ChemSpider 13851383 YesY
ChEMBL CHEMBL1224557 YesY
Jmol-3D images Image 1
Properties
Molecular formula C7H8S
Molar mass 124.20 g/mol
Appearance colourless liquid
Odor leek or garlic-like
Density 1.058 g/mL
Melting point −30 °C (−22 °F; 243 K)
Boiling point 195 °C (383 °F; 468 K)
Solubility in water low
Solubility very soluble in ethanol, ether
soluble in CS2
slightly soluble in CCl4
Refractive index (nD) 1.5751 (20 °C)
Hazards
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g., diesel fuel Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 70 °C (158 °F; 343 K)
LD50 493 mg/kg (rat, oral)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Benzyl mercaptan is an organosulfur compound with the formula C6H5CH2SH. It is a common laboratory alkylthiol and occurs in trace amounts naturally. Condensed tannins can undergo acid-catalyzed cleavage in the presence of a nucleophile like benzyl mercaptan. Benzyl mercaptan has been identified in boxwood (Buxus sempervirens L.) and is known to contribute to the smoky aroma of certain wines.[1] It also occurs naturally in coffee.

It is created by the reaction of benzyl chloride and sodium hydrosulfide.

Use in organic synthesis[edit]

The compound is used as a source of the thiol functional group in organic synthesis. It is introduced by S-alkylation to give alkyl benzylthioethers. Debenzylation is effected by dissolving metal reduction taking advantage of the weakened S-benzyl bond:[2]

RSCH2C6H5 + 2 "H" → RSH + CH3C6H5

Methoxy-substituted derivatives of benzyl mercaptan have been developed, which cleave easily, are recyclable, and are odourless.[3]

References[edit]

  1. ^ Contribution of benzenemethanethiol to smoky aroma of certain Vitis vinifera L. wines. Tominaga, Takatoshi; Guimbertau, Guy; Dubourdieu, Denis, 2003
  2. ^ Norman Kharasch and Robert B. Langford (1973), "2,4-dinitro-Benzenesulfenyl chloride", Org. Synth. ; Coll. Vol. 5: 474 
  3. ^ M. Matoba, T. Kajimoto, M. Node "Development of a Novel Benzyl Mercaptan as a Recyclable Odorless Substitute of Hydrogen Sulfide" Synlett 2007, pp. 1930-4. doi:10.1055/s-2007-984524