| 摘要 |
<p>1,257,853. 4,4-Diisocyanatodiphenyl methane and composition. SUMITOMO CHEMICAL CO. Ltd. 24 June, 1969 [1 Feb., 1969], No. 31963/69. Heading C2C. A polyamine mixture suitable for producing simultaneously 4,4<SP>1</SP>-diphenylmethane diisocyanate and a polyisocyanate composition preferably containing 50-60% by weight of 4,41-diphenylmethane diisocyanate and the remainder polyisocyanates comprises reacting aniline with formaldehyde in a ratio of 1.5 to 2À3 moles of aniline per mole of formaldehyde in the presence of a mineral acid of 0À7 to 0À95 times the stoichiometric amount of aniline at an initial temperature of 15 to 50‹ C. for at least one hour and at a final temperature of more than 50‹ C. to complete the reaction. Subsequently the polyamine mixture may be phosgenated and 4,4<SP>1</SP>-diphenylmethane diisocyanate and the polyisocyanate composition separated from the resulting polyisocyanate mixture or the separation and phosgenation procedures may be reversed.</p> |
