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2,5 bis (isocyanato methyl) the production mannered null 2,5 bis
2,5 bis (isocyanato methyl) the production mannered null 2,5 bis
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机译：2,5之二（异氰酸根合甲基）生产方式无效2,5之二
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摘要
PROBLEM TO BE SOLVED: To provide a method for producing 2,5-bis(isocyanatomethyl)-1,4-dithian by which the compound useful as a raw material for an optical product, especially a plastic lens having a high refractive index is produced by a short reaction process at a high yield by using a specific compound as a starting material. ;SOLUTION: The objective compound of formula II is obtained by performing a fosgenation of 2,5-bis(aminomethyl)-1,4-dithian of formula in an organic solvent (e.g. o-dichlorobenzene). The phosgenation is preferably performed by cold and hot two step method, e.g. the cold reaction is preferably performed at the reaction temperature of ≤30≤ and the latter step of the high temperature reaction is preferably performed by gradually increasing the temperature to the temperature of about 130-180°C required for finishing the reaction while blowing phosgene therein to finish the reaction.;COPYRIGHT: (C)1998,JPO
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