Variation 1 Ring-Opening Metathesis Polymerization ROMP

The ring opening metathesis polymerization (ROMP) of norbomene and other cyclic alkenes has been studied in liquid and supercritical CO2 (Scheme 4.7-19). Polynorbomenamer (Norsorex ) has very poor solubility in CO2 and the reactions proceed as precipitation polymerizations. The mthenium salt [Ru(H20)6](Tos)2 is also virtually insoluble in pure CO2 and the results with this catalyst proved difficult to reproduce because of variations in catalyst purity and reaction mixture agitation [98]. The catalytic performance could be greatly improved by working in C02/MeOH mixtures. The microstmcture of the polymer was found to be almost identical for samples prepared in neat norbomene or in CO2 and greatly differed from that obtained in MeOH or CO2/ MeOH mixtures [99]. 

Fig. 4.24. Another variation of the alkyne metathesis reaction alkyne ring-opening metathesis polymerization (alkyne ROMP).

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