Abstract: A process for separating a gaseous reaction mixture in the preparation of trioxane is described, in which a) the gaseous mixture leaving the reactor is scrubbed in countercurrent with an organic solvent whose boiling point is above 135.degree. C. in which the trioxane predominantly dissolves and which leaves the formaldehyde predominantly in the gas phase which is returned to the reactor, b) the trioxane together with residual formaldehyde is stripped from the solvent by distillation via a column, the overhead product being partially condensed in the temperature range from 62.degree. to 100.degree. C. c) some of the resulting condensate is applied to the column as reflux and some is taken off as product and d) the non-condensed portion is returned to the scrubbing step a).

Abstract: A process for removing trioxane from a liquid mixture containing trioxane, water and formaldehyde, which includes distilling the liquid mixture in a first distillation stage at a low pressure, distilling the resulting distillate in a second distillation stage at a higher pressure and taking off trioxane as bottom product.

Abstract: In the process for the preparation, with simultaneous end group stabilization, of polyacetal copolymers in a homogeneous phase and working up thereof, cyclic formaldehyde oligomers are copolymerized with cyclic acetals in the presence of an initiator in a polymerization reactor and immediately thereafter the initiator is deactivated by addition of basic substances, the unstable chain ends being degraded down to 0.01% to 1% in the presence of residual monomer, the product losing the majority of the residual monomer at the reactor outlet by letting down into a pelletizing device and the residual monomer which remains and the impurities dissolved in the product being removed by extraction with solvents and the product being pelletized, after drying and stabilization.

Abstract: A process for the catalytic preparation of trioxane from formaldehyde in the gas phase employs a catalyst comprising vanadyl hydrogenphosphate hemihydrate which may be unactivated or activated by steam.No byproducts were obtained in the process and the space-time yield is high. Deposits in the reactor do not occur.

Abstract: In a process for the preparation of trioxane from formaldehyde in the gas phase in the presence of a catalyst, the catalyst employed is 11-molybdo-1-vanadophosphoric acid, H.sub.4 PVMo.sub.11 O.sub.40 .multidot.n H.sub.2 O (n=0-32).Advantages of this process are, inter alia, high space-time yields and the suppression of byproducts.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a process and an embedding system for embedding tissue samples in a mixture of a hydroxyalkyl (meth)acrylate and an alkyl (meth)acrylate in a weight ratio of at most 9:1. The embedding process takes place at low temperatures using a low-temperature initiator system. It is thereby possible largely to retain the enzyme activity and the cell morphology.

Abstract: The invention relates to a process for the continuous manufacture of trioxan, if appropriate together with cyclic formals, from aqueous formaldehyde solutions in a circulation reactor with an evaporator, wherein the vapor/liquid mixture, before it enters the reactor, is separated into the vapor phase and the liquid phase, and subsequently the two phases are fed separately to the reactor. In particular, high space-time yields can be achieved by the process according to the invention. Moreover, equipment for carrying out this process is a subject of the invention.

Abstract: 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.

Abstract: Poly(acrylic acid) salts having specific structural characteristics, which salts are useful for combatting virus diseases.

Abstract: Esters of acrylic acid and methacrylic acid may be polymerized with the aid of either free radical forming or ionically effective initiators. The stereospecificy of the polymers may be influenced by the selection of specific initiators; magnesium-organic compounds are suitable for the synthesis of isotactic polymers. Acrylic acid and methacrylic acid esters having a high degree of isotacticity and a narrow molecular weight distribution are obtained with the aid of substituted phenylmagnesium halides. They are suitable as gauge and as test substances.

Abstract: This invention relates to an improvement in the process for the preparation of a polyhydroxy methylene ether in which polyhydroxy methylene is reacted with an alkylating agent in an aqueous alkaline medium, the improvement comprising that the alkylating agent has at least one ionic or ionizable carboxyl group, phospho group, quaternary ammonium group, or substituted amino group. The invention also relates to ion exchangers composed of the polyhydroxy methylene ethers.

Abstract: A process and device for determining a hormone in a liquid such as blood wherein measured amounts of the liquid to be tested, of a radioactively-labelled hormone, and of a hormone-binding protein or antibody, all present in a measuring vial, are contacted with an adsorbing vial formed from a mixture of a thermoplastic resin and an ion exchange resin for adsorbing unbound hormone, and the residual radioactivity of the liquid mixture is then measured after draining back into said measuring vial.