Przemyslaw Kubisa studied the use of ionic liquids in polymerization. His 2004 review examined their solvent role, including effects on polymerization kinetics and separation of polymer from catalyst-containing reaction media.[ref]
The solvent is part of the chemical system rather than merely an inert container. It can alter the environment of an active chain end, the solubility of growing chains and the partition of catalyst and product. Consequently equal monomer conversion in two media does not guarantee equal chain lengths or equal product purity.
An original ideal-chain calculation makes one distinction precise. Suppose of monomer is combined with of initiator, every initiator forms exactly one growing chain, and there is no chain transfer or termination. At conversion , the degree of polymerization contributed by incorporated monomer isIf only half the initiator forms chains under the same assumptions, that average becomes 160, despite equal monomer conversion. Conversely, chain transfer can increase the chain count and lower the average.
The model is deliberately idealized, not a measurement in Kubisa's review. It shows why solvent comparisons need chain-count and molecular-size information as well as reaction yield. A solvent enabling convenient catalyst recovery still requires separate evidence for its influence on the polymerization mechanism.
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