Rh(II)-Catalyzed Reactions of Diazoesters with Organozinc Reagents
作者:Robert Panish、Ramajeyam Selvaraj、Joseph M. Fox
DOI:10.1021/acs.orglett.5b01836
日期:2015.8.21
Rh(II)-catalyzed reactions of diazoesters with organozinc reagents are described. Diorganozincreagents participate in reactions with diazo compounds by two distinct, catalyst-dependent mechanisms. With bulky diisopropylethyl acetate ligands, the reaction mechanism is proposed to involve initial formation of a Rh-carbene and subsequent carbozincation to give a zinc enolate. With Rh2(OAc)4, it is proposed that initial
Molecularly oriented, silane-crosslinked ultra-high-molecular-weight polyethylene molded article and process for preparation thereof
申请人:MITSUI PETROCHEMICAL INDUSTRIES, LTD.
公开号:EP0229477A2
公开(公告)日:1987-07-22
If ultra-high-molecular-weight polyethylene having an intrinsic viscosity (q) of at least 5 dug is grafted with a silane compound in the presence of a radical initiator and extrusion-molded and the extrudate is impregnated with a silanol condensation catalyst after or during drawing and is then exposed to water to effect crosslinking, there is obtained a novel molecularly oriented molded article in which increase of the melting temperature, which is not observed in conventional draw-molded or crosslinked molded articles of polyethylene, can be attained, and even if this molecularly oriented molded article is exposed to a temperature of 180°C for 10 minutes, the molded article is not fused but the shape is retained and even after this heat history, a high strength retention ratio can be maintained. In this draw-molded article, the adhesiveness and creep resistance are prominently improved while high elastic modulus and high tensile strength inherent to a draw-molded article of ultra-high-molecular-weight polyethylene are retained.