摘要:
A nickel/aluminum oxide catalyst having a nickel content from 10 to 60% by weight, based on the total catalyst, in which the nickel is in the form of crystallites having an average diameter ranging from 15 nm to 50 nm.
摘要:
Multilayer plastic pipes comprising a polyamide-based inner and outer layer, wherein the inner and outer layer are connected force-lockingly by means of at least one intermediate layer made of a mixture of a linear crystalline polyester and a polyamide, have improved stability to chemical agents and improved mechanical properties.
摘要:
Polysulfide compounds and vulcanization compositions containing the polysulfide compounds, for use in vulcanizing rubbers, are disclosed, with the polysulfide compounds being of the formula ##STR1## wherein R.sup.1 -R.sup.4 are each, independently, hydrogen or C.sub.1 -C.sub.4 alkyl and n is 2 to 10wherein the polysulfide compounds can be used alone or in a vulcanization composition containing the polysulfide compound, sulfur, one or more additional accelerators, one or more basic compounds and, optionally, conventional rubber additives, to provide vulcanized products with improved reversion stability and ageing stability.
摘要:
A multilayer plastic pipe having improved barrier action against diffusion of the substance being transported, particularly methanol-containing fuels, dimensional stability, and resistance to mechanical stress, is provided comprising:an inner layer and an outer layer, each of which comprise a polyamide-based molding composition, wherein the inner layer and outer layer may be the same or different, andat least one intermediate layer comprising a linear, crystalline polyester-based molding composition interposed between and bonding together the inner and outer layers.
摘要:
For the preparation of 2-cyanoacetoxypropionic esters, a mixture of lactic ester and cyanoacetic ester is introduced, an alkali metal alcoholate is added as catalyst and the mixture is heated while the alcohol eliminated during the course of the reaction is distilled off. The course of the reaction is followed by means of gas chromatographic analysis and the reaction is terminated prior to eliminating the theoretical amount of alcohol by destroying the catalyst by acidification. The reaction mixture is worked up by distillation and the product easily separated from the reaction mass due to the substantial absence of high boiling components.
摘要:
Liquid-melt aliphatic dicarboxylic acids tend to undergo undesirable discoloration during prolonged storage. The discoloration can be avoided by an addition of 0.1 to 3.0% by weight of a primary amine.
摘要:
Heat is transferred in a thermodynamic system with a heat transfer medium which is at least one fluid of formula I and/or II, ##STR1## wherein R.sub.1 is ethyl or hydrogen, R.sub.2 is ethyl, R.sub.3 is methyl and R.sub.4 is a benzyl radical.
摘要:
A method for eliminating mercury from mercury containing liquids by contacting the mercury-containing liquid with a plurality of fibers wherein the fibers making up the plurality of fibers have a coating of silver on the surface of the fibers, and a silver-coated fiber for use in the method are disclosed.
摘要:
Foamed polyolefin particles are prepared by dispersion foaming of components consisting essentially of polyolefin particles, a liquid dispersing agent and optionally a volatile blowing agent in a reaction system consisting essentially of a reactor equipped with a stirrer containing said components and a discharge jet, comprising the step of:gassing the components of the reactor by injecting an inert gas into the dispersion below the surface of the liquid in the reactor;and simultaneouslydischarging a three phase mixture of liquid dispersing agent, polymer particles and gas through said jet.
摘要:
A colorless and transparent, amorphously processable polyamide molding composition which has a good resistance to stress cracking and good impact strength and is resistant to alcohols, esters, ketones, fuels and boiling water, comprising the reaction product ofI. a linear aliphatic dicarboxylic acid;II.a) 35-60 mol % of trans,trans-bis(4-aminocyclohexyl)-methane; andII.b) 65-40 mol % of other aliphatic, cycloaliphatic, araliphatic or aromatic diaminesas starting components, the molar ratio of components I and II varying in the range from 0.95 to 1.05:1, preferably 0.98 to 1.02:1.The polyamide molding composition is particularly suitable for use for spectacle frames, apparatus inspection windows and covers and lamp covers.