摘要:
Silicate catalysts which can be employed for selective oxidation reactions of organic substances, a process for the preparation of these catalysts and their use are described.The catalyst is distinguished by high long-term activity, by the reaction temperature required for the reaction being lower in comparison with catalysts composed of pure silver and by higher conversions and selectivities in the oxidative dehydrogenation of alkanols in comparison with pure silver or silver on supports.
摘要:
The process dehydrogenates methanol in the presence of a catalyst based on aluminum oxide, alkali metal aluminate and/or alkaline earth metal aluminate with the exclusion of oxygen at a temperature of 650.degree. to 1050.degree. C. in a reactor whose inner wall is composed entirely or partly of aluminum oxide. The process gives anhydrous formaldehyde which contains only very minor impurities.
摘要:
A process for the preparation of carbonyl compounds by the oxydehydrogenation of (C.sub.1 -C.sub.4)-alcohols is carried out at a temperature from 400.degree. to 700.degree. C. in the presence of a silicate catalyst which has been doped with silver and silver ions. By means of the process carried out at relatively low temperatures, for example, are that high yields are achieved, the content of carbon monoxide is low and the product gas contains, apart from carbon dioxide, no further determinable by-products and has a low water/formaldehyde ratio.
摘要:
The invention relates to a process for obtaining trioxane from aqueous solutions by high-pressure extraction using an extracting agent which is in the form either of a gas in the supercritical state or of a liquid gas. An intermediate separation is advantageous, especially in the former case.The trioxane can be obtained in high concentration and with a saving of energy by the process according to the invention.
摘要:
Continuous process for removing unstable components from crude oxymethylene copolymer, which still contains catalysts, monomeric starting materials and unstable components, by treating the copolymer with deactivators, optionally in the presence of auxiliaries, in a pressure zone, and subsequently removing volatile components in a pressure-release zone in the presence or absence of stabilizers, in which process the crude polymer is fully melted in the absence of the deactivators and auxiliaries immediately after completion of the polymerization step, and the deactivators are subsequently incorporated, alone or together with auxiliaries, under pressure into the resultant polymer melt in at least one pressure zone.By this process, degradation is avoided and significantly better properties are obtained.
摘要:
The invention relates to a process for the continuous preparation of trioxane, optionally together with cyclic formals, from an aqueous formaldehyde solution in the presence of acidic solid-bed catalysts, the reaction taking place without simultaneous evaporation.The process according to the invention can be carried out even at high formaldehyde concentrations without appreciable paraformaldehyde deposits.
摘要:
The invention provides a process for the continuous manufacture of trioxan, optionally together with cyclic formals, from aqueous formaldehyde solutions in a circulation reactor with evaporator, the vapor/liquid mixture leaving the evaporator is fed in below the liquid level of the reaction mixture. The process of the invention allows to attain especially high space/time yields.
摘要:
A process for the simultaneous synthesis of trioxan and cyclic formals is provided, which comprises reacting a mixture of concentrated formaldehyde and diol and/or epoxide with acid catalysts at a temperature of from 30.degree. to 150.degree. C.
摘要:
In the case of polyolefins filled with alkaline earth metal carbonates, a very good compatibility of the hydrophilic filler and the hydrophobic polymer matrix is reached when using as adhesion promoters certain organo-phosphorus compounds. As a result, improved mechanical properties are obtained with the articles made of plastic material that has been prepared from such polyolefin molding compositions.