摘要 |
<p>1386197 Treatment of diisocyanato-diphenylmethane BAYER AG 2 March 1973 [4 March 1972] 10164/73 Heading C2C A non-yellowing diisocyanato - diphenylmethane is prepared by treating an impure commercial diisocyanato-diphenylmethane with a metal chloride of the general formula wherein Me is a divalent iron, zinc or cadmium cation, a trivalent aluminium, bismuth or iron cation, or a tetravalent tin cation, and n is an integer of 2 to 4 depending on the valency of Me, the treatment being carried out with a solution of the metal chloride in an alkylene glycol carbonate. The glycol carbonate is preferably ethylene glycol carbonate.</p> |