1118-15-6Relevant articles and documents
Experimental and theoretical studies on ethylene polymerization using SiO2-supported silyl chromate type catalysts prepared by a green method
Li, Xiaofang,Cheng, Ruihua,Luo, Jun,Dong, Qi,He, Xuelian,Li, Liuzhong,Yu, Yongling,Da, Jianwen,Liu, Boping
, p. 56 - 65 (2010)
SiO2-supported silyl chromate catalyst (UCC S-2 catalyst) is an important catalyst for the commercial production of polyethylene. Cann first reported a possible green synthesis route for the preparation of S-2 catalyst through transformation from Phillips catalyst by addition of triphenylsilanol (TPS) to avoid the use of toxic bis(triphenylsilyl) chromate (BC). In this work, this green synthesis route was further investigated by the combination of experimental and theoretical methods. The obtained catalyst was named as PS catalyst based on the incomplete conversion of Phillips catalyst to S-2 catalyst. Polymerization activity of PS1.5 catalyst was higher than that of S-2 catalyst with either TEA or MAO as cocatalyst. The existence of the simultaneously formed hydroxyl group and its coordination to the reduced Cr site was favorable to the PS catalyst, and this might attribute to the higher polymerization activity of PS catalyst than that of S-2 catalyst. A further modification of PS catalyst by a series of alkyl chlorosilane compounds showed that the role of the electron-withdrawing group only limited at a certain distance away from Cr active site. This preliminary study provided a solid basis for a further innovation of PS catalysts and final substitution of S-2 catalyst in commercial processes.
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Lucas,Martin
, p. 5225 (1952)
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The complex compound and its manufacturing method org. tantalum
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Paragraph 0146-0156, (2016/10/07)
Disclosed is an organotantalum complex compound, which is easily cured by ultraviolet (UV) light, enables patterning, provides a coating film having excellent uniformity when being formed into a coating film, and is formed into a cured product having high resistance to etching using an etching gas. Also disclosed are a method for producing the organotantalum complex compound and a photocurable composition comprising the organotantalum complex compound. The organotantalum complex compound is obtained by reacting a ?-diketone compound (A) having at least one organic group with a photopolymerizable carbon-carbon unsaturated bond with a tantalum alkoxide compound (B) at a specific ratio to obtain a reaction product, and then, reacting the reaction product with a disiloxanediol compound (C) using a specific amount of the disiloxanediol compound (C).
Formation of silicones mediated by the sponge enzyme silicatein-α
Wolf, Stephan E.,Schlossmacher, Ute,Pietuch, Anna,Mathiasch, Bernd,Schroeder, Heinz-C.,Mueller, Werner E. G.,Tremel, Wolfgang
experimental part, p. 9245 - 9249 (2011/01/11)
The sponge-restricted enzyme silicatein-α catalyzes in vivo silica formation from monomeric silicon compounds from sea water (i.e. silicic acid) and plays the pivotal role during synthesis of the siliceous sponge spicules. Recombinant silicatein-α, which was cloned from the demosponge Suberites domuncula (phylum Porifera), is shown to catalyze in vitro condensation of alkoxy silanes during a phase transfer reaction at neutral pH and ambient temperature to yield silicones like the straight-chained polydimethylsiloxane (PDMS). The reported condensation reaction is considered to be the first description of an enzymatically enhanced organometallic condensation reaction. The Royal Society of Chemistry.
