摘要:
Disclosed is a process for the preparation of aryl-substituted propionic acid esters having the formula: wherein R and R 1 are a C 1 -C 12 linear or branched alkyl, a C 5 -C 12 cycloalkyl, a C 6 -C 12 aryl or a C 7 -C 12 alkaryl or aralkyl, R 2 is hydrogen or a C 1 -C 20 linear or branched alkyl and R 3 is a C 1 -C 20 linear or branched alkyl, a C s -C 12 cycloalkyl, a C 6 -C 12 aryl or a C 7 -C 20 alkaryl or aralkyl, and may be the same or different, which comprises forming a reaction mixture of a phenol, at least one base catalyst and an acrylate, in the presence of a complexing agent effective in increasing the rate of reaction, wherein (i) substantially all of the side-product is removed from said reaction mixture prior to the addition of the complexing agent and (ii) all or substantially all of the acrylate is added at once to the reaction mixture. The process results in higher yields of the desired product, in a shorter period of time, with a reduction of undesirable by-products.
摘要:
Procédé de polymérisation en phase gazeuse d'oléfines de formule CH2 = CHR dans laquelle R représente l'hydrogène ou un alcoyle ou un radical arylé ayant de 1 jusqu'à 8 atomes de carbone. Le procédé est réalisé dans un ou plusieurs réacteurs à lit fluidisé ou agité mécaniquement, au moyen d'un catalyseur obtenu par réaction d'un halogénure de titane ou d'un haloalcoolat et éventuellement d'un composé donneur d'électrons supporté sur un dihalogénure Mg actif à l'aide d'un composé Al-trialcoyle et éventuellement d'un composé donneur d'électrons. Le procédé comprend les étapes suivantes: a) la mise en contact des composants du catalyseur; b) la prépolymérisation du propylène ou des mélanges de celui-ci avec des quantités minimales d'éthylène ou d'une alpha-oléfine de manière à former un polymère de propylène cristallin; et c) la polymérisation d'une ou plusieurs oléfines CH2 = CHR dans la phase gazeuse en présence du système de prépolymère-catalyseur obtenu dans b) tout en maintenant en phase gazeuse un alcane dans une concentration molaire par rapport à l'oléfine comprise entre 20 et 80 %.
摘要:
Sheets and manufactured articles with polyolefin matrixes, comprises reinforcement fibers, are produced by thermoforming mats that comprise polyolefin fibers and bunches of reinforcement fibers of appropriate length. The aforementioned mats are prepared with mixing technique which do not entail opening the bunches of reinforcement fibers.
摘要:
Process for the gas-phase polymerization of olefins of the formula CH₂=CHR in which R is hydrogen or an alkyl or aryl radical with 1 to 8 carbon atoms carried out in one or more reactors having a fluidized or mechanically agitated bed, using a catalyst obtained by reaction of a titanium halide or haloalcoholate and optionally an electron-donor compound supported on an active Mg dihalide with an Al-trialkyl compound and optionally an electron-donor compound, comprising the steps of: a) contacting the catalyst components in the absence of the olefin; b) prepolymerizing propylene or mixtures of propylene with minor amounts of ethylene or an alpha-olefin to form a propylene polymer with an insolubility in xylene of at least 60% by weight, in an amount of from 0.5 to 1000 g per g solid catalyst component; and c) polymerizing one or more CH₂=CHR olefins in the gas phase in the presence of the prepolymer-catalyst system obtained in b) while maintaining in the gas phase an alkane in a molar concentration with respect to the olefin of from 20 to 80%.
摘要:
Disclosed is a process for making a normally solid, gel-free, amorphous to predominantly crystalline, propylene polymer material having free-end branches of propylene units and strain hardening elongational viscosity by peroxide decomposition of the propylene polymer material in the substantial absence of oxygen at certain temperatures for certain periods of time, and then deactivating the free radicals in the material.