Allyl iso-thio-cyanate

Oil of Mustard.—Only the last compound named is important, viz., allyl iso-thio-cyanate, CH2 = CH—CH2NCS. Strange as it may seem, from statements made in connection with the cyanates and iso-cyanates of the saturated series, this compound is made by treating allyl-iodide, not with silver thio-cyanate, but with potassium thio-cyanate. As, however, the tautomeric iso-compounds are made from the cyanates and thio-cyanates by heat, the conversion of the first formed thio-cyanate into the iso-thio-cyanate can readily be understood. 

Allyl iso-thio-cyanate is found in nature as a glucoside constituent of mustard seed. It is known, therefore, as mustard oiL It is a liquid with a sharp odor and with a boiling point of 150.7 . The proof that it is iso-thio-cyanate is its conversion into allyl-amine, CH2 = CH—CH2NH2. 

Allyl Cyanide, Iso-thio-cyanate, etc.—From allyl chloride or the iodide there may be prepared by the customary reactions allyl cyanide and other of the cyanogen compounds. With potassium cyanide allyl iodide yields allyl cyanide. The reaction, however, instead of yielding a cyanide of the expected constitution is accompanied by a shifting of the double bond to the second carbon so that the cyanide has a constitution unlike that of the iodide from which it is made. 

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