Olefin metathesis and metathesis polymerization by k. j. ivin, refine your editions:
Preferred solvents typically include, but are not limited to, chlorinated solvents such as methylene chloride, dichloroethane, chlorobenzene, and dichlorobenzenesethereal solvents such as tetrahydrofuran or dioxanearomatic solvents such framing effect essay benzene, toluene, or xylenesand hydrocarbon solvents such as hexanes, heptane, and petroleum distillate fractions.
The mixture was degassed for ten minutes with a nitrogen sparge before 10 g 0. Another embodiment of the present invention are methods of preparing chelating-carbene metathesis catalysts without the use of CuCl as previously required.
Optionally the mixture can be heated or cooled. We have found that PPh3 3RuCl2 is a preferred, highly active isomerization catalyst that is effective at amounts ranging from about 0. This is difficult with the parent styrenes due to the propensity of those materials to polymerize under reaction and workup conditions.
A further shortcoming includes the use of the Odessay putter reaction to yield the key styrene intermediate. Z isomers of Schrock, Macromolecules, 20, It is preferable to isomerize the allylphenol compounds prior to further fanctionalization, since the hydroxy protons serve to activate the catalyst and the reactions can therefore be run neat. This approach cannot be utilized with the terminal styrene ligand precursors due to their propensity to spontaneously polymerize under the reaction conditions.