PURPOSE: To provide a relatively simple method for producing an isocyanate or an isocyanate mixture which contains substantially no color causing substance in high yield, a method for manufacturing an isocyanate which contains substantially no color causing impurity, and a method for producing a light-colored polyurethane foam.
CONSTITUTION: An isocyanate or an isocyanate mixture which contains substantially no color causing substance is produced by phosgenating the amine corresponding to the isocyanate and treating the isocyanate-containing phosgenation mixture with hydrogen in the presence of a supported catalyst. The supported catalyst is in a form such that its shortest dimension is from about 0.3 to about 3.0 mm. The catalyst has a BET surface of from about 0.5 to about 150 m2/g. An alkaline substance must not exist in the catalyst. These isocyanates are particularly useful for the production of light-colored foams.
MANFURETSUDO GARUSU
HERUBERUTO GEBAUERU
OTSUTOO IMERU
KURISUTEIINE MENDOOTSUAAFUROON
RAINHARUTO RANGERU
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