| 摘要 |
The invention consists in a process for the simultaneous preparation of (1) a mixture of 78-82% by weight of 2,4-tolylene diisocyanate and 22-18% by weight of 2,6-tolylene diisocyanate and (2) a tolylene diamine phosgenation product comprising a solution in tolylene diisocyanate of congeneric non-volatile polyisocyanate solutes, the solution having an amine equivalent between 90 and 125 and "amino equivalent" being defined as the weight of sample containing one equivalent weight (42 grams) of NCO group. The two products are made by (a) distilling a tolylene diamine phosgenation product (prepared by phosgenating a mixture of 2,4- and 2,6-tolylene diamines) until the distillate contains 78-82% of 2,4-tolylene diisocyanate and 22-18% of 2,6-tolylene diisocyanate and (b) returning sufficient of the distillate to the distillation vessel to yield a product of the required amine equivalent. Both the products are known starting materials for the manufacture of polyurethanes. An example is given. |
