13052-77-2Relevant articles and documents
Highly active chromium-based selective ethylene tri-/tetramerization catalysts supported by PNPO phosphazane ligands
Zhou, Yusheng,Wu, Hongfei,Xu, Sheng,Zhang, Xuejun,Shi, Min,Zhang, Jun
, p. 9545 - 9550 (2015/06/16)
Novel Cr(iii) catalysts supported by PNPO phosphazane ligands of the type Ph2PN(R)P(Ph)OAr have been prepared, all of which, upon activation with MMAO-3A, are highly active in ethylene tri-/tetramerization with considerable selectivity. The effect of ligand substitution on the catalytic performance has been examined. The Cr precatalyst supported by the PNPO phosphazane ligand with an N-cyclohexyl achieved high activity of 316.7 kg (g Cr h-1)-1 and a high total selectivity of 85.1% towards valuable 1-hexene (45.7%) and 1-octene (39.4%) using chlorobenzene as the solvent at 35 bar and 40 °C. In methylcyclohexane, the precatalyst supported by [Ph2PN(iPr)P(Ph)OPh] exhibited a higher 1-octene selectivity (54.0%) with a considerable activity of 73.3 kg (g Cr h-1)-1 at 35 bar and 40°C. With the fine-tuned ligand backbone, such a PNPO phosphazane-based catalyst system provides a mode for precise understanding of the impact of ligand variations on catalytic performance.
METHOD FOR SEPARATING SALIFIED PHENOLIC COMPOUNDS
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Page/Page column 8, (2012/10/23)
A method for separating a salified phenolic compound from a reaction medium including same is described. Also described, is a method for separating salified phenolic compounds from an aqueous reaction medium resulting from the reaction of a phenolic compound and glyoxylic acid in the presence of a base, which leads to a reaction medium including at least the excess of the starting salified phenolic compound and the various salified mandelic compounds resulting from the reaction, wherein the reaction medium including the starting salified phenolic compound is contacted with an adsorbent substrate. This leads to the selective adsorption of the phenolic compound onto said substrate and to the recovery of an aqueous flow containing the salified mandelic compounds from the reaction, and in that the phenolic compound attached onto the adsorbent is desorbed by means of a regenerating treatment of the adsorbent.
KINETICS AND MECHANISM OF CLEAVAGE OF MODEL 2-AROXYALKYLAROMATIC STRUCTURES OF LIGNIN UNDER THE ACTION OF ANTHRAHYDROQUINONE IN ALKALINE MEDIUM
Maiorova, E. D.,Platonov, A. Yu.,Evstigneev, E. I.,Chistokletov, V. N.
, p. 959 - 963 (2007/10/02)
The kinetic and activation parameters of the cleavage of interunit alkylaryl ether bonds of lignin under conditions of caustic anthraquinone digestion have been determined using α-carbonyl nonphenolic model compounds.The values of the activation energy and reaction entropy indicate the bimolecular character of the reaction of anthrahydroquinone with carbonyl structures.Based on the results obtained, we advance a hypothesis on the active participation of the non-phenolic structure of lignin in the process of delignification under caustic anthraquinone digestion.
