Catalysis alkene polymerisation

The earliest chemistry of the type has been connected with alkene polymerisation catalysis and has been reviewed [1,2]. To form... 

Ca.ta.lysts, A small amount of quinoline promotes the formation of rigid foams (qv) from diols and unsaturated dicarboxyhc acids (100). Acrolein and methacrolein 1,4-addition polymerisation is catalysed by lithium complexes of quinoline (101). Organic bases, including quinoline, promote the dehydrogenation of unbranched alkanes to unbranched alkenes using platinum on sodium mordenite (102). The peracetic acid epoxidation of a wide range of alkenes is catalysed by 8-hydroxyquinoline (103). Hydroformylation catalysts have been improved using 2-quinolone [59-31-4] (104) (see Catalysis). 

In this paper the author presents some of his contributions to the theory and practice of the cationic polymerisation (CP) of alkenes since 1944. The first phase of his work at the University of Manchester comprises the discovery of co-catalysis by water with TiCl4, the invention of the pseudo-Dewar reaction vessel, the use of trichloroacetic acid as co-catalyst, and the disproof of the alleged cationic isomerisation of cis-stilbene. 

Dimetallocycles have been discovered which exhibit high reactivity with respect to carbon-carbon bond-making and -breaking processes. They allow the synthesis of a variety of simple but important hydrocarbon ligands bridging a dinuclear metal centre. y-Carbene complexes are readily available by several routes and their reactions have implications for both alkyne polymerisation and alkene metathesis. A substantial chemistry of organic species co-ordinated at dinuclear metal centres is in prospect, with significance for metal surface chemistry and catalysis. 

Treatment of [CpTiCl(dmpe)2] with one equivalent of MeLi affords [CpTi(Me)(dmpe)2]. This complex is an active catalyst for the oligomerisation of ethene to but-l-ene, 2-ethylbut-l-ene and 3-methylpent-l-ene. The mechanism of the catalysis is proposed to involve titanacyclopentane intermediates. The complex [Cp TiMe2][MeB(C6Fj)3] acts as both a Ziegler-Natta catalyst for the polymerisation of alkenes, such as ethene and propene, and as a carbocationic initiator for the polymerisation of election rich alkenes such as A -vinylcarbazole and vinyl ethers. It also polymerises styrene to syndiotactic polystyrene, probably via a carbocationic initiated polymerisation. 50... 

The reaction between [Cp2ZrCl2] and either EtMgCl or Et2Mg-dioxane has been investigated and complexes 49 and 50 have been obtained in the latter the alkene was best described as a C2H/ anion. The energy profile for ansa-bridged zirconocene Ziegler-Natta catalysis was obtained from experimental rate data. The Zr and Hf complexes 51 have been prepared and shown to polymerise ethene in the presence of The Zr complex 52 has been... 

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