Albemarle Corporation

Michael D Matthews

Kaung-Far Lin

Arcelio J Malcolm

James E Boone

John C Prindle

Sharon D Booth McGee

A highly efficient method of producing alkyl mercaptan and/or dialkyl monosulfides which involves employing carbon dioxide as an internal coolant is described. Only negligible amounts of carbonyl sulfide were formed. In addition, relatively easy separation of carbon dioxide from the reaction mixture facilitates an efficient coolant recycle process, giving a simple and effective mode of temperature control.

Method for producing alkyl mercaptans and/or dialkyl monosulfides

N-�4-(Cyanoethylthiomethyl)-2-thiazolyl!guanidine, is prepared by (a) mixing 1,3-dihaloacetone and 2-imino-4-thiobiuret in a suitable polar organic solvent at initial temperatures of about -10.degree. to about 25.degree. C., and agitating the mixture at about -10.degree. to about 60.degree. C. for at least about 1 hour; (b) heating the resultant mixture at about 40.degree. to about 60.degree. C. for at least about 0.5 hour; (c) mixing with the mixture from (b), thiourea and then water at about 40.degree. to about 60.degree. C. for a period of at least about 1 hour; (d) removing liquid polar solvent from the mixture of (c); and (e) mixing with the mixture from (d), 3-halopropionitrile and water-soluble alcohol, ether, or ether-alcohol, followed by aqueous alkali metal hydroxide while maintaining the temperature at below about 20.degree. C., to form N-�4-(cyanoethylthiomethyl)-2-thiazolyl!guanidine. The process avoids isolating and purifying any of the intermediates, and can be conducted in the same vessel, as a 'one-pot' synthesis.

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Michael D Matthews