摘要:
A process is described for the polymerization of ethylene or copolymerization of ethylene with a C.sub.3 to C.sub.15 alpha olefin in solution, suspension or in the gas phase at 20.degree. to 250.degree. C. and 1 to 100 bars in the presence of a mixed catalyst comprising a separately produced halogen-containing titanium(III) compound and an organoaluminum compound while controlling the molecular weight with oxygen, wherein a mixture of organoaluminum compounds is employed comprising a halogen-containing aluminum alkyl and a trialkyl aluminum compound in a molar ratio of 1:0.05 to 1:20, the combined amount of organoaluminum compounds being present in an amount of 0.01 to 20 moles per one mole of halogen-containing Ti(III) compound.
摘要:
An improvement in a process for the preparation of an ethylene homopolymer or a copolymer of ethylene with an .alpha.-olefin containing 3 to 15 carbon atoms by contacting the monomer or mixture of monomers in solution, suspension or in gas phase at 20.degree. to 250.degree. C. at a pressure of 1 to 50 bar with a mixed catalyst comprising a chlorine containing titanium (III) compound and an organoaluminum compound in the presence of hydrogen, the improvement residing in employing as the organoaluminum compound a trialkylaluminum compound in an amount of 0.1 to 20 mol per mol titanium (III) compound and including in the polymerization mixture oxygen at a concentration of 0.001 to 0.1 volume percent based upon the amount of ethylene. By carrying out the polymerization by including oxygen in the polymerization reaction mixture and employing trialkylaluminum compound as the organoaluminum compound the mean molecular weight of the polymer can be regulated while obtaining a desired molecular weight distribution.
摘要:
An improvement in a process for the manufacture of .beta.-(dimethylamino)-propionitrile by contacting acrylonitrile with dimethylamine, the improvement residing in passing the reactants in countercurrent with respect to one another in a bubble column reactor and reacting them therein at a temperature between 25.degree. and 80.degree. C., preferably 40.degree. to 60.degree. C.
摘要:
A continuous process for the manufacture of .alpha.-cyano-ethylated aliphatic aldehydes by continuously passing acrylonitrile and aldehyde through a tubular reaction zone and therein contacting the same with an alkali hydroxide at a temperature between 20.degree. and 120.degree. C, the contact of the acrylonitrile and aldehyde with the alkali hydroxide being for a brief period of time and thereafter immediately separating the reaction product from the alkali hydroxide. Unreacted acrylonitrile and aldehyde can be recycled to the tubular reactor and additional alkali hydroxide can be added to make up for any losses.
摘要:
A process for the manufacture of bis-(2-cyanoethyl)-amine wherein gaseous ammonia is reacted with acrylonitrile having a 5-15% by weight water content in a bubble column reactor. The reaction is carried out at a temperature of about 20.degree.-80.degree. C.
摘要:
Pulverulent ultra-high molecular weight polyethylene, alone or as a mixture with other polyethylenes, is compacted into extrudates by extrusion agglomeration under pressure at temperatures of 100.degree. to 150.degree. C. over average residence times in the die of 2 to 40 seconds and at a compression ratio of 1:5 to 1:15, and the extrudates are divided into pellets.
摘要:
Copolymers consisting of 95 to 50 weight percent of ethylene and 5 to 50 weight percent of methoxyacetic acid vinyl ester and having a molecular mass from 500 to 10,000 g.times.mole .sup.-1. Methods for preparation and use are also disclosed. The copolymers are used as flow improvers for mineral oil distillates, in particular mineral oil middle distillates.
摘要:
An olefin polymerization catalyst comprising a chromium compound deposited on a carrier, which chromium compound is complexed with a straight-chain, branched-chain, or cyclic aliphatic hydrocarbon or mixture thereof such that the mol ratio of aliphatic hydrocarbon to chromium compound is 1:2-3, said chromium compound being deposited on said carrier material in an amount between 10.sup..sup.-3 and 10 millimols chromium compound per gram of carrier material, said carrier material also containing a trialkyl, tricycloalkyl, triaryl, monohalodihydrocarbyl, or monoalkoxydihydrocarbyl aluminum compound; a process for preparing such an olefin polymerization catalyst and the use of such catalyst in the polymerization of olefins, particularly ethylene, propylene, 2-methylpropylene and butene-1.
摘要:
It is described a method for selecting a transmission mode for a radio data transfer between a user equipment and a base station of a telecommunication network. The method includes (a) determining the quality of a radio link, which extends between the user equipment and the base station, (b) determining the radio load within the telecommunication network, and (c) selecting a transmission mode based on the quality of the radio link and on the radio load. It is further described a control device for selecting a transmission mode for a radio data transfer between a user equipment and a base station and a computer program for controlling the described transmission mode selection method.
摘要:
The homo- or copolymerization of ethylene at temperatures of 150.degree. C. to 350.degree. C. and pressures of 300 to 3500 bar is carried out in the presence of catalysts having an organometallic compound of a metal of Group III of the Periodic Table of the Elements and a titanium compound. The titanium compound is the reaction product of (a) a titanic acid ester and (b) the product of the reaction of a magnesium alcoholate and a halogen-containing aluminum alkyl compound.