PRODUCTION OF VINYL ACETATE - VINYL ESTER COPOLYMERS HAVING A LOW CONTENT OF HIGH-BOILING VINYL ESTERS
申请人:Kohler Thomas
公开号:US20100227995A1
公开(公告)日:2010-09-09
The invention relates to a method for the production of vinyl acetate-vinyl ester copolymers having a low content of high-boiling vinyl esters by the radically initiated polymerization of 4.9 to 95 wt.-% vinyl acetate, 4.9 to 95 wt.-% of one or more high-boiling vinyl esters, and optionally 0.1 to 40 wt.-% of one or more ethylenically unsaturated auxiliary monomers, characterized in that additionally 0.1 to 40 wt.-% of vinyl acetate is added at a conversion rate of the polymerization of 65 to 99.9%, wherein the amounts given in wt.-% each refer to the total weight of the monomers, and add up to 100 wt.-%.
Photochemistry of Diaryl Vicinal Tetraketones and Chemistry of Intermediate (Aroyloxy)arylketenes<sup>1</sup>
作者:Mordecai B. Rubin、Marina Etinger、Moshe Kapon、Eric C. Krochmal、Raisa Monosov、Stephan Wierlacher、Wolfram Sander
DOI:10.1021/jo971247q
日期:1998.2.1
observed photoproducts via intermediate beta-lactones. The latter are formed with a high degree of stereoselectivity. The failure of a cyclic tetraketone to react is attributed to its inability to undergo the cyclic mechanism proposed for formation of ketenes from tetraketones. Dimesityl and di-tert-butyl tetraketones react by a competing intramolecular hydrogen atom transfer mechanism. Dimerization of (b