PURIFICATION OF EPISULFIDE COMPOUND

摘要

PROBLEM TO BE SOLVED: To provide a method for purifying the subject compound in order to enhance the quality of optical materials such as plastic lens which are obtained by curing polymerization of the above compound and have the balance between high refractive index and high Abbe's number, by filtering a specific episulfide compound maintained at a specific temperature. SOLUTION: This method comprises filtering an episulfide compound having one or more epithio structure(s) of formula I (R1 is a 1-10C hydrocarbon; R2 to R4 are each a 1-10C hydrocarbon or H; Y is O, S, Se or the like; and (m) and (n) are each 0 or 1) per molecule [e.g. bis(β-epithiopropyl)ether] while maintaining the compound at a temperature between its solidifying point and 20 deg.C, using a filter made of polypropylene or the like with a pore diameter of pref. 0.05-10.0μm to purify the subject compound. The above-mentioned episulfide compound is obtained, for example, by reacting a compound of formula II [e.g. a bis(β-epoxypropyl)ether] with thiating agent such as a thiocyanate salt.