Journal ArticleDOI
W(CO)6/CBr4/hv — a new system for metathesis polymerisation
B Gita,G. Sundararajan +1 more
TLDR
In this paper, an optimization study of W(CO) 6 CBr 4 / hv is presented, where the active species are characterised by reaction with acetophenone and copolymers of phenylacetylene and norbornene.Abstract:
Metathesis polymerisation can be effected with many catalysts under a variety of conditions. The system described here, viz., W(CO) 6 CBr 4 / hv , induces polymerisation by in situ generation of the active species and has not been reported in the literature so far. In this paper, optimisation studies of this system, yields obtained with various monomers and characterisation of the active species are discussed. Variation of different parameters such as the ratio of W(CO) 6 :CBr 4 , the time of photolysis and the effect of solvents as well as that of the metal carbonyls have been studied. In addition, copolymers of phenylacetylene and norbornene have been synthesised. We have also attempted to characterise the active species responsible for the polymerisation by reaction with acetophenone.read more
Citations
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Catalytic activity of carbonyl precursor based W/Al2O3 and CoW/Al2O3 catalysts in hydrodesulfurization of thiophene
TL;DR: In this article, a mixture of carbonyl precursors based W/Al 2 O 3 and CoW/Al O 3 catalysts were prepared by controlled and gradual gas phase adsorption in a fluidized bed reactor.
Reference EntryDOI
Ring‐Opening Metathesis Polymerization
TL;DR: In this article, the authors defined transition metal-based initiators for ring-opening metathesis polymerization (ROMP) and provided a well-defined transition transition metal based initiator for ROMP.
Journal ArticleDOI
Chemical modifications of oxide surfaces
E.F. Vansant,Pegie Cool +1 more
TL;DR: In this paper, various synthesis and post-synthesis techniques are described in order to provide some insights into the latest developments in pore size engineering in various oxides, such as zeolites and clay minerals.
Journal ArticleDOI
Carbonyl‐precursor‐based W/Al2O3 and CoW/Al2O3 catalysts: characterization by temperature‐programmed methods
TL;DR: In this article, the surface species formed during the gradual and controlled preparation process were studied by temperature-programmed methods, and the results of PCO and NH3-TPD measurements indicated that when the controlled gas phase preparation method is applied to zerovalent carbonyl precursor, the unfavourable formation of tungsten oxide can be minimized.
Journal ArticleDOI
Metathesis polymerisation of phenylacetylene catalysed by (arene)Mo(CO)3 activated by electron acceptor chloranil
N.S. Santhosh,G. Sundararajan +1 more
TL;DR: In this paper, it was shown that better control over polymer molecular weight and polydispersity was achieved with prior mixing of the metal carbonyl complex with the acceptor and by delaying the addition of the monomer.
References
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Journal ArticleDOI
A novel route to block copolymers by changing the mechanism from living ring-opening metathesis polymerization of cyclic olefins to aldol condensation polymerization of silyl vinyl ethers
Wilhelm Risse,Robert H. Grubbs +1 more
TL;DR: Synthese de polynorbornene et poly(exodicyclopentadiene) avec un groupe terminal aldehyde par polymerisation puis reaction avec le terephtalaldehyde as discussed by the authors.
Journal ArticleDOI
Block and graft copolymers by living ring-opening olefin metathesis polymerization
Wilhelm Risse,Robert H. Grubbs +1 more
TL;DR: A review of titanacyclobutane-initiated "living" olefin metathesis polymerization for the preparation of new polymer structures is given in this paper, where the same type of reaction was used to link preformed polymer blocks to give ABA-type triblock copolymers and graft Copolymers.
Journal ArticleDOI
Reaction de metathese des olefines induite photochimiquement en presence d'un complexe de metal de transition : VI. Existence probable d'un metallodichlorocarbene primaire
TL;DR: In this paper, a mechanism for the formation of these compounds is outlined, and the mechanism for their formation is described in terms of the insertion of metalladichlorocarbene moieties into the carbon double bond.
Journal ArticleDOI
The photoinduced metathesis of olefin catalyzed by W(CO)5L-AXn system
TL;DR: In this article, the metathesis of internal and terminal olefins was investigated in photocatalytic systems containing tungsten compounds of the type W(CO)5L (L = CO, py, PPh3, Cl−).
Journal ArticleDOI
From the reaction of metal—carbene complexes with cyclic enol ethers to the synthesis and structure of μ-alkylidene complexes of tungsten and their possible implication in the olefin metathesis reaction
TL;DR: The reaction of a metathesis catalyst prepared from W(CO) 6 /CCl 4 /hν with cyclic enol ethers gives products arising from the probable insertion of a dichlorocarbene complex of tungsten into the carbon-carbon double bond.