| 摘要 |
A method of concentrating a solution of methylene diphenyl diisocyanate in diphenyl oxide, which includes cooling the solution until part of the solution crystallizes, thereby forming a solid phase having a lower concentration of the methylene diphenyl diisocyanate, and a liquid phase having a higher concentration of the methylene diphenyl diisocyanate than in the original solution, and then separating the solid and liquid phases. The method is particularly applicable to the concentration of solutions of 4,4'-methylene diphenyl diisocyanate in diphenyl oxide. |
