简洁
发表于 2025-3-25 04:33:47
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间接
发表于 2025-3-25 09:53:15
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难管
发表于 2025-3-25 11:57:42
,‘Colours and Cries, Buff and Blue’,as widely been believed that the steric regulation in the isotactic propagation stage is effectuated by the chiral structure around the catalyst sites. A number of proposals concerning possible structures of the catalyst site have been presented. Most of the proposed mechanism for the steric course
micronized
发表于 2025-3-25 18:30:50
,‘Colours and Cries, Buff and Blue’,eactive for the polymerization of epoxides to give high molecular weight polyethers. Condensates of organotins with alkyl phosphates are highly reactive catalysts and give highly crystalline polymers of epoxides. The condensates obtained from Friedel-Crafts type metal halides give less crystalline p
Dislocation
发表于 2025-3-25 21:24:11
,The Business of Government, 1835–41, organometallic compounds..Triphenyl group-IVB-metal hydroxides, Ph.MOH (M = Sn, Pb), as well as group IVB organometallic oxides, sulphides and selenides of the type R.MX or R.MXMR. (X = 0, S, Se) yield very active catalysts upon 1/1 interaction with Et.Zn. The reaction products of 2-hydroxyethyl (t
贿赂
发表于 2025-3-26 01:50:03
,Anthony Powell’s Archetypal Characters, the aluminumalkyl/water/acetyl-acetone (1/0.5/1) initiator system. The polymers are of high molecular weight with a M. of 250,000 and a polydispersity slightly more than the most probable molecular weight distribution of 2. Homopolymers and copolymers with cyclic ethers have been characterized by s
Dealing
发表于 2025-3-26 05:08:57
,Anthony Powell’s Archetypal Characters,clic monomers using chiral initiators..The use of the same initiators is now applied to disubstituted monomers..Trans dimethylthiirane, a racemic monomer, mixture of two stereoisomers bearing two asymmetric carbons of identical configuration, give by polymerization optically inactive composed of -RS
嘲弄
发表于 2025-3-26 10:13:10
,Orwell’s Fictions of the Thirties, to the preparation of optically active poly(alkyl vinyl ether)s by starting both from optically active monomers and racemic ones have been presented. In particular, to approach the mechanistic aspects of the stereospecific heterogeneous catalytic systems based on alkyl or alkoxy aluminum and sulphu
角斗士
发表于 2025-3-26 13:50:54
,Anthony Powell’s Archetypal Characters,the 2-methyl-2-phenylp. ropyl group). Neophylzirconium aluminate or hydridozirconium aluminate supported on alumina are extremely active catalysts for high temperature (300°C) polymerization of ethylene. The high catalyst efficiency and the innocuous nate of the catalyst residues eliminate the need
frozen-shoulder
发表于 2025-3-26 18:33:02
,Density, Pressure and Hooke’s Law,ssure with no other components necessary. The polymer prepared from (I) and ethylene is essentially linear high density polyethylene. During the.ethylene polymerization, there is a fairly rapid catalyst-destroying termination reaction which limits mileage to about lg mmole of Scandium. Compound (I)