摘要:
Fluorenyl-containing silyl bridged metallocenes, the process of using such metallocenes to polymerize olefins, and the resulting unusual syndiotactic polypropylene are disclosed.
摘要:
Aliphatische ω-Difluorcarboxylverbindungen werden auf wirtschaftliche Weise aus aliphatischen ω-Monohalogen-difluor-carboxylverbindungen hergestellt, indem man letztere mit Wasserstoff in Gegenwart eines auf einem inerten Trägermaterial aufgebrachten Katalysators, der eines oder mehrere Metalle der VIII. Gruppe des Periodensystems enthält, bei 120 bis 250°C in Kontakt bringt.
摘要:
Process for preparing α-arylpropionic acids by catalytically asymmetrically hydrogenating α-arylpropenoic acids utilizing an asymmetric hydrogenation catalyst at low temperatures and, optionally, at high pressures.
摘要:
Procédé de préparation d'un acide hydroxyphénylacétique de formule (I)
où R = H, alcoyle ou alcoxy ainsi que de ses sels, caractérisé par le fait que l'on fait réagir, en milieu aqueux, à une température supérieure ou égale à 50°C, l'acide hydroxymandélique correspondant, libre ou salifié, de formule (II)
où R a la signification donnée précédemment et M = H, Na, ou K en présence de nickel en poudre fine et d'un hydroxyde métallique de formule (III)
M₁OH (III)
où M₁ = Na ou K et est identique à M dans le cas où M représente également Na ou K , de manière à ce que le milieu réactionnel présente un pH égal ou supérieur à 9, pour obtenir le sel correspondant de l'acide hydroxyphénylacétique de formule (I) que, si désiré, l'on déplace selon les méthodes usuelles pour obtenir l'acide correspondant que l'on isole ou, si désiré, l'on salifie selon les méthodes usuelles, et acide orthohydroxyphénylacétique ainsi obtenu.
摘要:
A process is disclosed for the treatment of a new or deactivated supported metal catalyst containing noble metal to prepare said catalyst for use in the hydrodehalogenation of a compound having the formula: CnHmFpXq, where each X is independently selected from Cl and Br, wherein n is an integer from 1 to 6, m is an integer from 0 to 12, p is an integer from 1 to 13, and q is an integer from 1 to 13, and wherein m+p+q equals 2n+2 for saturated compounds which are acyclic, m+p+q equals 2n for saturated compounds which are cyclic and for olefinic compounds which are acyclic, and m+p+q equals 2n-2 for olefinic compounds which are cyclic, comprising the step of contacting said catalyst with an atmosphere comprising chlorine gas at a temperature from about 100 °C to 400 °C for a time sufficient to improve the catalytic activity thereof for said hydrodehalogenation. A process is also disclosed for catalytic hydrodehalogenation characterized by using a supported metal catalyst containing noble metal which has been so contacted with an atmosphere comprising chlorine.
摘要:
Fluorenyl-containing metallocenes are disclosed along with methods for making the metallocenes. Also disclosed are methods for using the metallocenes as polymerization catalysts. In addition, polymers resulting from such polymerizations are disclosed.
摘要:
Fluorenyl-containing metallocenes are disclosed along with methods for making the metallocenes. Also disclosed are methods for using the metallocenes as polymerization catalysts. In addition, polymers resulting from such polymerizations are disclosed.