THERMAL-STABILITY OF A POLYMER-SUPPORTED RHODIUM CATALYST FOR METHANOL CARBONYLATION

A novel rhodium-containing diphenylphosphinate copolymer of styrene ad divinylbenzene (used as catalyst for methanol carbonylation) was prep ared and studied by means of thermoanalytical methods. Simultaneous TG -DTA experiments were run to assess the effect of the grafting procedu re on the thermal behaviour. Additional information concerning the str uctural modifications observed was obtained by infrared spectroscopy. On the basis of the collected evidences the cited catalysts were found to be stable up to 250 degrees C in the presence of nitrogen and ther eafter progressive degradation took place. Such high thermal stability is consistent with the experimental conditions used (T=230 degrees C, PCO+H2= 210 bar) for the recently reported methanol carbonylation pro moted by iodomethane which leads to a mixture of C-2-C-6 carboxylic ac ids.