Silica → Toluene 2,4-Diisocyanate

Participants

Reaction Conditions

Reaction Steps

170 Parts of 2,4-di-(butoxycarbonylamino)-toluene were dissolved in 350 parts of dodecylbenzene. With a feed rate of 300 liters per liter of reaction volume an hour, this solution was fed into a separating reactor of quartz glass filled with an aluminum graulate having a grain size of 1 millimeter to 3 millimeters and heated to a temperature of 320° C. Using 8 liters of nitrogen per liter of reaction mixture an hour as a stripping agent, the butanol resulting from the reaction was separated in a gaseous form and condensed in a vessel cooled with dry ice. This resulted in 443 parts of reaction discharge from which 81 parts of 2,4-toluene diisocyanate (88.2 theoretical percent relative to reacted 2,4-di-(butoxycarbonylamino)-toluene) were obtained by distillation at a temperature between 76° C. and 82° C. and a pressure of 0.2 millibar. The raw material had reacted completely. A mixture of refluxable 2-butoxycarbonylamino-4-isocyanatotoluene and 4-(butoxycarbonylamino)-2-isocyanototoluene was proven in the distillation residue by means of gas chromatography.

Provenance & Evidence