To produce a crude MDI having an isocyanate content as high as possible, a total chlorine content as low as possible and an iodine color number as low as possible and excellent in storage stability by minimizing the shortcomings of the prior art.
A mixture of diphenylmethane diisocyanate and polyphenyl polymethylene polyisocyanate, which exhibits reduced iodine color number and contains reduced chlorine component, is produced by reacting a mixture of diphenylmethane diamine and polyphenyl polymethylene polyamine corresponding to the objective material with phosgene in the presence of at least one kind of inert organic solvent under heating, separating and removing excess phosgene from the solvent after the termination of phosgenation and treating the reaction product under heating. In this reaction process, a mixture of water and at least one kind of monovalent or polyvalent polyoxyalkylene alcohol or their mixture is added to the reaction mixture after the termination of the phosgenation in an effective amount in the presence or absence of phosgene.
BERUNTO BURUFUMAN
ROORANTO MINGESU
PEETAA KERAA
BUIRII BUAN PEE
BUORUFUGANGU HAIDAA
ZUIIKUMUNTO POORU
BERUNHARUTO OTSUTOO
PAURU YAKOBUSU
BUIRUFURIITO ZEIFUERUTO
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