Organic Preparations with Molar Amounts of Volatile Malodorous Thiols

Abstract

Thiols are indispensable for the preparation of many organic sulfur compounds. Their strong smell and use for gas leakage perception render it almost impossible to work with them without arousing public attention. Molar amounts of the very odoriferous thiol 2-methyl-2-propanethiol (t-butylthiol) are needed, for example, for the large-scale synthesis of two useful synthetic building blocks, 1,2,4,5-tetrakis(t-butylthio)benzene and tetramethylbenzo-2,2,6,6-[1,2-d;4,5-d']bis[1,3]dithiol. We investigated an array of alternatives to circumvent the problem: (1) alternative thiols (primary, long-chain, tertiary thiols of larger molar mass); (2) exhaust cleaning methods (adsorption, oxidation, conversion to a salt); and (3) thermal exhaust treatment. Only combustion of the fumehood exhaust with domestic gas at 900 °C in a regenerative thermal oxidation unit was able to completely prevent the thiol smell from escaping.

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GRAPHICAL ABSTRACT

Keywords:

• Exhaust air treatment
• 2-methyl-2-propanethiol
• odor of thiols
• stench
• thermal exhaust treatment

Notes

^a Scheme 2, method a.

^b Scheme 2, method b.

^c Synthesis according to Ref. 22.

^d Synthesis according to Ref. 23.

^e Un-identifiable product mixture.

^f Not synthesized, thiol smell much too storng.

^g Not synthesized, thiol insoluble in toluene.

^h Synthesis according to Ref. 31.

ⁱ Incomplete substitution.

^j Not synthesized.