6974-12-5Relevant articles and documents
Fourth subgroup metal complex with rigid annular bridging structure and application of fourth subgroup metal complex
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Paragraph 0058; 0061; 0067, (2021/06/23)
The invention belongs to the technical field of olefin polymerization catalysts, and particularly relates to a fourth subgroup metal complex with a rigid annular bridging structure and an application of the fourth subgroup metal complex. The fourth subgroup metal complex provided by the invention has a structure represented by a formula (A) or a formula (B), X is halogen or alkyl; and M is titanium, zirconium or hafnium. On the basis of a non-metallocene catalyst, a bridging structure in catalyst molecules is improved and upgraded, and a brand-new metal complex with excellent catalytic performance and good high-temperature tolerance is designed; when the fourth subgroup metal complex is used as a main catalyst to catalyze olefin polymerization reaction, under the activation action of a small amount of mixed cocatalyst, the fourth subgroup metal complex can efficiently catalyze the copolymerization reaction of ethylene and alpha-olefin to obtain polyolefin with high molecular weight and high comonomer insertion rate.
Batchwise and continuous organophilic nanofiltration of Grubbs-type olefin metathesis catalysts
Schoeps, Dirk,Buhr, Kristian,Dijkstra, Marga,Ebert, Katrin,Plenio, Herbert
experimental part, p. 2960 - 2965 (2009/12/08)
A mass-tagged N-mesityl imidazolinium salt with four additional -CH 2NCy2 substituents was synthesized, leading to a molecular mass of nearly 1100 g mol-1 in the corresponding carbene ligand. This mass-tagged ligand was used to generate the respective Grubbs II and Grubbs-Hoveyda type complexes. The catalytic activity of the latter complex was tested in several olefin metathesis reactions and found to be slightly superior to that of the related N-mesityl based complex. In batchwise solvent resistant nanofiltration experiments the ruthenium complex dissolved in toluene and following a metathesis reactions was efficiently retained (>99.8%) by a single nanofiltration; the permeate contained less than 4 ppm of Ru. Equally efficient catalyst retention was observed in a membrane reactor utilized for the continuous synthesis of a RCM product.
Cross-metathesis of vinylsilanes carrying electron-withdrawing substituents with olefins in the presence of the second-generation Grubbs catalyst
Pietraszuk, Cezary,Marciniec, Bogdan,Fischer, Helmut
, p. 7121 - 7124 (2007/10/03)
The efficient cross-metathesis of vinylsilanes carrying electron-withdrawing substituents with various olefins is described. High yields and selectivities were obtained when styrene, 1-hexene, and selective functional allyl derivatives were used as the ol
Efficient procedures for 1-bromo-1,3-butadiene and 2-bromo-1,3-butadiene
Keegstra,Verkruijsse,Andringa,Brandsma
, p. 721 - 726 (2007/10/02)
Mixtures of Z- and E-1-bromo-1,3-butadiene in which the E- or Z- isomer predominates have been obtained in good yields by treating a mixture of Z- and E-1,4-dibromo-2-butene (90% Z-isomer) or pure E-1,4-dibromo-2-butene, respectively, with powdered potassium hydroxide in high-boiling petroleum. 2-Bromo-1,3-butadiene was obtained in high yields by stirring a mixture of vinylacetylene, concentrated aqueous hydrogen bromide and copper(I) bromide.
