Synthesis method of 4-methanesulfonylbutyl isothiocyanate

The invention relates to a chemical synthesis method of 4-methanesulfonylbutyl isothiocyanate (Erysolin). The method comprises that 1-bromo-4-chlorobutane and hydrous sodium methyl mercaptide as starting raw materials undergo a reaction to produce chlorothioether, the chlorothioether and phthalimide potassium salt undergo a reaction to produce a tertiary amine conjugate, the tertiary amine conjugate undergoes a hydrazinolysis reaction to produce thioether primary amine, the thioether primary amine forms isothiocyanate under action of thiophosgene, and the isothiocyanate is oxidized to form Erysolin. The chemical synthesis method is simple in operation, uses a small amount of dangerous reagents, gives consideration to a cost and a yield and is suitable for Erysolin industrial production.