| 摘要 |
PROBLEM TO BE SOLVED: To obtain a new polyisocyanate compound having a sulfur atom in a main skeleton, capable of providing an optical material such as lens of glasses, etc., having a high refractive index, a low dispersion and excellent solvent resistance. SOLUTION: This compound is shown by formula I (Z is a 1-6C chained alkylene or a chain thiaalkylene containing one or more sulfur atoms in which the total of carbon and sulfur atoms is 3-6; (m) and (n) are each 0-3) such as 1,1,6,6-tetrakis(isocyanatomethyl)2,5-dithiahexane, etc. The compound is obtained by forming a tetracarboxylic acid ester derivative of formula II (R1 and R2 are each a lower alkyl) from a dithiol compound of the formula HS-Z-SH, reacting the derivative with hydrazine monohydrate, etc., to give a tetracarbonyl hydrazide derivative of formula III, then reacting the derivative with nitrous acid in an aqueous solution of hydrochloric acid and thermally transforming the reaction product to convert a carbonyl hydrazide group into an isocyanate group.
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