Phenol → 4,4-Diaminodiphenylmethane

Participants

Reaction Steps

The di-formamide of 4,4′-methylene-dianiline is prepared by the reaction of the diamine with 2.1 molar equivalents of formic acid, and removing the water byproduct by azeotropic distillation with toluene. Using the same apparatus as Example 1, but without the addition funnel, diphenyl carbonate (48.45 grams, 0.226 mole) and 4,4′-MDA-di-formamide (6.92 grams, 0.0272 mole), containing 0.21 grams of phenol, is heated to reflux at 38 mmHg. Reaction and phenol/phenyl formate distillation commences at a pot temperature of 155° C., and ceases 30 minutes later at a pot temperature of 195° C., 17 mmHg. IS/GC analysis of the condensate (10.55 grams) shows only phenyl formate, phenol and a trace of DPC. The pot material (43.97 grams) contains 3.02 grams of 4,4′-diphenylmethane diisocyanate (MDI) and 3.21 grams of MDI as the mono-phenol carbamate, a recovery of 0.0249 mole equivalents of MDI, equal to a 91.6% yield, based on di-formamide charged.

Provenance & Evidence