摘要:
Process for preparing hydrocyanic acid by catalytic dehydration of gaseous formamide, wherein the dehydration of formamide is coupled with an exothermic reaction by the reactor used in the dehydration comprising two separate fluid paths which are separated by a common reactor wall, with one fluid path being provided for the dehydration of formamide and the second fluid path being provided for the exothermic reaction.
摘要:
A process for preparing ethylene polymers by the high-pressure method comprises dissolving one or more free-radical initiators in one or more ketones of the formula I where R1 and R2 are identical or different and are selected from among C1-C6-alkyl and C3-C12-cycloalkyl and R1 and R2 may also be covalently linked to one another to form a 4- to 13-membered ring, prior to the polymerization, compressing the solution, metering it into the polymerization reactor at one or more points and subsequently carrying out the polymerization at from 150 to 380° C. and from 500 to 4500 bar.
摘要:
Pigment concentrates comprising at least one pigment and one polyolefin wax prepared from one or more olefins by catalysis with a single-site catalyst comprising a transition metal of groups 5 to 8 of the Periodic Table, where the complex contains not more than one cyclopentadienyl system per transition metal atom, the concentrates comprising a thermoplastic, if desired, and additives, if desired.
摘要:
The invention relates to a method for producing supported chromium catalysts for the polymerisation of olefins by loading a xerogel support with chromium by adding to the xerogel support a volume of a 0.025 to 15% by weight solution of a chromium compound or a volume of a solution comprising from 0.025 to 7.8% by weight of Cr which is essentially converted into a chromium(VI) compound on heating in a water-free stream of gas under oxidizing conditions at temperatures in the range from 300 to 1100° C. for a period of from 10 to 1000 minutes in a solvent which comprises a maximum of 20% by weight of water, and subsequently evaporating the solvent, where the volume of the chromium salt solution employed is smaller than the pore volume of the xerogel support.
摘要:
A process for coating a reactor, which comprises depositing a metal layer or a metal/polymer dispersion layer on the internal surface of the reactor in an electroless manner by bringing the surfaces into contact with a metal electrolyte solution which, besides the metal electrolyte, comprises a reducing agent and optionally a halogenated polymer to be deposited in dispersed form.
摘要:
Oxidized waxes are obtainable by oxidation of polyolefins obtainable by means of metallocene catalysis and having a molecular weight Mw in the range from 1000 to 40,000 g/mol.
摘要:
A process for compressing ethylenically unsaturated monomers at a pressure of 200-5000 bar in the absence of a polymerization initiator comprises carrying out compression in the presence of a sterically hindered amine derivative.
摘要:
Fluorescent pigments contain essentially a polymer matrix based on polymethyl methacrylate and a nonpolar fluorescent dye from the coumarin or perylene series, the polymer matrix being a crosslinked polymethacrylate or polyacrylate prepared by suspension polymerization.
摘要:
Polymers that can be obtained by suspension polymerization of 50 to 100% by weight of at least one compound selected from the group comprising C.sub.1 -C.sub.18 -alkyl esters of acrylic acid and methacrylic acid, and 0 to 50% by weight of further, free radical-polymerizable monomers in the presence of a buffer selected from the group comprising citric acid, alkali metal citrates, alkaline earth metal citrates and ammonium citrates, and also a process for preparing these polymers and their use in the production of molded articles.
摘要:
Carboxyl-containing isobutene copolymers are obtainablea) by cationic polymerization of a mixture of from 1 to 99 mol % of isobutene and from 99 to 1 mol % of a 2-methylalk-1-ene at less than 20.degree. C. in the presence of a halogen-containing Lewis acid andb) subsequent grafting of the isobutene copolymer obtainable in this manner with an .alpha.,.beta.-ethylenically unsaturated carboxylic acid or carboxylic acid derivative at above 100.degree. C. and in the presence of a free radical initiator.Such carboxyl-containing isobutene copolymers are particularly suitable as adhesive raw materials or as sealing compounds.