ABSTRACT
Metathesis reactions are very attractive since by this reaction olefins can be converted into new products via the rupture and reformation of carbon-carbon
“DK3029_C016” — #2
double bonds (Equation [16.1])
2RCH=CHR′ ↔ RCH=CHR + R′CH=CHR′ (16.1)
The key step in this process is the reaction between an olefin and a transition metal carbene complex in a 2 + 2 fashion to generate an unstable metallacyclobutane intermediate. This intermediate can revert either to the starting olefin or open productively to afford a new metal carbene and produce a new olefin. Metathesis reactions open up new industrial routes to important petrochemical intermediates, polymers, special chemicals, and oleochemicals. The metathesis reaction was discovered by Banks and Bailey at Phillips PetroleumCo. when looking at the conversion of olefins into high octane gasoline via olefin-isoparaffin alkylation [1]. Propene molecules were split over supported molybdenum catalysts instead of alkylating the paraffin, and propene was converted into ethene and butene. Since that discovery, industrial applications of the olefin metathesis reaction progressively increased, and other metathesis reactions, such as ring-opening metathesis polymerizations (ROMP) of cyclic olefins, became of great interest. An overview of the current industrial applications of olefin metathesis has recently been published [2]. Based on the existing process for the production of olefins and a limited volume of raw olefins, applications of the olefin metathesis reaction to convert less desirable olefins to more useful ones represent a great potential. This is illustrated by the conversion of low value olefins produced by Fischer-Tropsch synthesis into high value olefins that can be employed in further downstream processes. A technological relevant metathesis reaction is the conversion of low value C7 α-olefins to internal C12 olefins, which can be used as detergent alcohol feedstock [2].
