摘要:
Process for preparing hydrocyanic acid, which comprises catalytic dehydration of gaseous formamide to give a product mixture comprising hydrocyanic acid, water, formamide, ammonia, CO and high boilers, separation of the product mixture by condensation of a condensate comprising water, formamide, high boilers and possibly ammonia and hydrocyanic acid from the product mixture obtained and partial or total recirculation of the condensate into a heat exchanger located downstream of the reactor.
摘要:
The present invention relates to solutions comprising water and at least one metal cyanide, at least a part of the water being obtained from wastewater which occurs as depleted wastewater in a process for extracting noble metals from noble metal-containing ores by the cyanide process, the process for the preparation of solutions according to the invention and to the use of the solutions according to the invention in a process for extracting noble metals from noble metal-containing ores by the cyanide process, to a process for extracting noble metals from noble metal-containing ores by the cyanide process, wherein the solution according to the invention is used, and to the use of depleted wastewater occurring in the extraction of noble metals from noble metal-containing ores by the cyanide process to the preparation of solutions comprising water and at least one metal cyanide.
摘要:
In a process for the polymerization of ethylene and optionally further monomers in a high-pressure reactor at from 120 to 350° C. and pressures of from 1000 to 4000 bar, hydrogen is intermittently introduced into the reactor.
摘要:
An ethylene terpolymer wax comprising, as monomer building blocks, from 35 to 95% by weight of ethylene, from 0.1 to 40% by weight of at least one ester of the formula I where R1 is selected from hydrogen, C1-C10-alkyl, C3-C12-cycloalkyl and C6-C14-aryl R2 are identical or different and are selected from hydrogen and C1-C10-alkyl, R3 is selected from C1-C10-alkyl, C3-C12-cycloalkyl and C6-C14-aryl and n is an integer from 2 to 100, and from 0.1 to 25% by weight of at least one carboxylic acid of the formula II where R4 is selected from hydrogen, C1-C10-alkyl, C3-C12-cycloalkyl and C6-C14-aryl.
摘要:
Pigment concentrates comprising at least one pigment, a polyethylene wax prepared from one ethylene and, if desired, one comonomer using a metallocene catalyst, if desired a thermoplastic polymer and, if desired, additives can be used to color plastic moldings and plastic sheets.
摘要:
The invention relates to a catalyst support and to a method for the production of the catalyst support comprising the following steps: a) production of a silicic acid hydrogel having a solids content of from 10 to 25% by weight (calculated as SiO2) whose particles are substantially spherical, b) extraction of the hydrogel particles with an alcohol until at least 60% of the water present in the hydrogel has been removed, c) drying of the resultant hydrogel until the residual alcohol content is less than 10% by weight (xerogel formation) at temperatures of ≧160° C. at atmospheric pressure using an inert entraining gas, d) setting of the desired particle size of the resultant xerogel, in which the hydrogel particles have a particle size of ≧8 mm before the extraction, and to a catalyst and to a method for the production of the catalyst by loading the catalyst support with a chromium compound. The invention also relates to a method for the production of polyolefins using the catalyst.
摘要:
Bimodal polyethylene blends are made from a high-molecular-weight ethylene copolymer and a low-molecular-weight ethylene homo- or copolymer and have a melt flow rate MFR 190/21.6 of from 6 to 14 g/10 min, a density of from 0.94 to 0.97 g/cm3, an environmental-stress-cracking resistance ESCR>150 h and a value of less than 3 when the quality of blending in the blend is measured to ISO 13949. A process prepares polyethylene blends of this type by melting and homogenization in a mixing apparatus and discharge via a gear pump. The blends are used to produce moldings, in particular hollow articles and pressure pipes.
摘要:
A catalyst composition suitable for the (co)polymerization of alk-1-enes is obtainable by mixing a metallocene complex with a C3-C20-alk-1-ene in an inert solvent, reacting the resulting mixture in a controlled manner with a compound capable of forming metallocenium ions and diluting the resulting mixture with an inert nonpolar, essentially aliphatic solvent, and also, if desired, applying the catalyst composition to a particulate support material.
摘要:
A catalyst solution for polymerizing &agr;-olefins is obtainable by reacting a metallocene compound with an activator compound which can react with the metallocene compound so as to displace a ligand from the central atom and stabilize the resulting cationic complex by a non-coordinating anion as an ion pair, adding one or more &agr;-olefins in a molar ratio of metallocene compound: &agr;-olefins of from 1:1 und 1:100 and mixing with at least 10 parts by volume of an aliphatic hydrocarbon.
摘要:
A process for preparing oxidized polyolefin waxes by reacting polyolefin waxes with oxygen or oxygen-containing gases at from 140 to 200° C. and at pressures of from 5 to 200 bar involves conducting the oxidation reaction continuously in a tube reactor but excludes the reaction of polyolefins prepared by metallocene catalysis.