Phenol → Tributylamine trihexylamine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

BPA (136.98 g; 0.600 mol) and DPC (133.67 g; 0.624 mol) were added into a liter melt polymerizer apparatus as powders. The reactor vessel was deoxygenated by evacuating it to about 1 torr and then refilling the apparatus with nitrogen. This deoxygenation procedure was repeated three times. The reactor vessel was immersed in a fluidized heat bath preheated to 180° C. The DPC/BPA mixture was allowed to melt, producing a colorless, homogeneous liquid; once a small amount of the mixture melts, the remaining material can be stirred slowly to promote better heat exchange. The system was allowed to thermally equilibrate (5-10 min). The solution was stirred at 250 rpm unless otherwise stated. Into this solution was syringed the tributylamine (361 ml; 1.5×10-3 mol) and trihexylamine (53.0 ml; 1.5×10-4 mol) catalysts. The resulting solution was stirred for 5 min at 180° C. At this time the reaction temperature was raised to 210° C. and the pressure lowered to 175 torr. The phenol began to distill out of the reactor vessel into an evacuated receiver flask immediately (3- 5 drops/sec). After 25 min, the reactor pressure was lowered to 100 torr and held there for another 25 min. Phenol continued to distill into the receiver flask (1-3 drops/sec). The reactor pressure was lowered to 15 torr while the temperature was raised to 250° C. These conditions were held for 30 min (approx. 1 drop/sec flow). The pressure was dropped to 2 torr while the temperature was increased to 285° C. These conditions were maintained for 10 min (flow to receiver approx. 1 drop/3 sec). The final stage of the reaction was initiated by placing the melt material under full vacuum (0.62 torr at the reactor head) at 305° C. for 0.5 h. Foaming began after 10 min at 305° C. and continued for about 10 min. The stirring rate was lowered to 150 rpm after 25 min. The melt polycarbonate appeared colorless with an IVchloroform =0.411 dl/g. The receiver mass (distillate; phenol+DPC+BPAtrace)=122.65 g; theoretical distillate mass (phenol+DPCexcess)=118.1 g. Polymer yield was 149.4 or 98.0%. Mw =16,856, Mn =8,377, Mw /Mn =2.01, (Mw /Mn)all =2.66.

Herkunft & Nachweise