Abstract: The invention relates to a process for recycling polythiourethanes. Disclosed herein is a process wherein polythiourethanes are depolymerized in the presence of di- or higher-functional thiols. Di- and/or higher-functional isocyanates, epoxides or ethylenically unsaturated compounds and optionally di- and/or higher functionalized thiols are subsequently added to the obtained monomer and oligomer mixture. The reaction mixture is then repolymerized. The process allows polythiourethanes to be recycled.

Abstract: The invention relates to a stabilizer system, in particular for thiol-ene and/or thiol-yne compositions, comprising: at least one free radical scavenger component, at least one acidic component, wherein the acidic component comprises one or more organic acids, and at least one sulfidic component selected from the group of organic sulfides. The stabilizer system according to the invention inhibits undesirable reactions in the thiol-ene composition or thiol-yne composition according to the invention during storage, so that longer storage is possible without influencing the quality. The stabilizer system according to the invention, however, does not mean that an intended reaction of the thiol with alkenes or alkynes in the respective thiol-ene and thiol-yne composition is no longer possible or is no longer possible at a sufficient speed.

Abstract: The invention has as subject matter a method for producing a polyurethane cast resin, wherein the production comprises the steps of mixing at least one thiol component with at least one isocyanate component, degassing of the mixture and hardening of the polyurethane polymer in a one-stage process. Cast resins for electronic or optoelectronic components of for the production of optical lenses are obtained by the method of the invention that have good mechanical properties and very good optical properties at the same time by a suitable combination of polythiols as hardening component with commercially available isocyanates. The addition of special isocyanates is also not very necessary, as is the case for carrying out the method in several stages. The method in accordance with the invention results in an economical, one-stage process in the properties of the cast resin that are necessary for the application range.

Abstract: The invention has as subject matter a method for producing a polyurethane cast resin, wherein the production comprises the steps of mixing at least one thiol component with at least one isocyanate component, degassing of the mixture and hardening of the polyurethane polymer in a one-stage process. Cast resins for electronic or optoelectronic components of for the production of optical lenses are obtained by the method of the invention that have good mechanical properties and very good optical properties at the same time by a suitable combination of polythiols as hardening component with commercially available isocyanates. The addition of special isocyanates is also not very necessary, as is the case for carrying out the method in several stages. The method in accordance with the invention results in an economical, one-stage process in the properties of the cast resin that are necessary for the application range.

Abstract: The present invention relates to terpene ethers of the general formula (I) in which the substituents have the meanings defined in the description, to a process for their preparation and to their use. The novel terpene ethers are suitable as traction fluids, as fragrances, as solvents and as reactive intermediates.

Abstract: The present invention relates to a process for the preparation of a particularly pure monochloroacetic acid, in which, in a first step, a hydrogenation of a mixture of mono- and dichloroacetic acid is carried out to a residual content of dichloroacetic acid of 400 to 600 ppm and, in a second step, this mixture is subjected to melt crystallization. The hydrogenation is carried out with a heterogeneous catalyst which comprises 0.1-5.0% by weight of palladium and in which active charcoal or silicon dioxide is used as the support.

Abstract: Process for regenerating a fluorination catalyst The invention relates to a process for regenerating a fluorination catalyst containing chromium and magnesium after use in a fluorination reaction, in which the used catalyst is treated with a mixture comprising at least 10 mol % of HF, from 30 to 90 mol % of O.sub.2 and from 0 to 60 mol % of inert gas.

Abstract: The present invention relates to a process for preparing a particularly pure glycolic acid by saponification with chloroacetic acid with an excess of alkali metal hydroxide, with the resulting alkali metal chloride being filtered off, and the 20 to 70% strength by weight glycolic acid solution being subsequently subjected to an electrodialysis at 20.degree. to 40.degree. C. and a cell voltage of 0.5 to 2.5 V per cell pair. The process of the invention permits optimum removal of sodium chloride and chloroacetic acid as necessary for preparing a particularly pure glycolic acid. Other organic acids, nitrogen compounds, aldehydes and salts are not produced in this process and thus do not affect the product quality.

Abstract: The invention relates to the preparation of trifluoroacetyl fluoride by reacting trichloroacetyl chloride with anhydrous hydrogen fluoride in the gaseous phase on a catalyst which is obtainable by reacting a water-soluble chromium (III) salt with magnesium hydroxide or magnesium oxide in the presence of water, converting the reaction mixture into a paste, drying the paste and treating it with hydrogen fluoride.

Abstract: The invention relates to a process for the preparation of trichloroacetyl chloride by reaction of acetyl chloride or acetaldehyde or chlorinated derivatives thereof with chlorine in the presence of active charcoal as the catalyst.

Abstract: Process for preparing trifluoroethyl sulfur compounds from thiolates and 1-chloro-2,2,2-trifluoroethane. The invention relates to the preparation of trifluoroethyl sulfur compounds of the formula RSCH.sub.2 CF.sub.3 by reacting 1-chloro-2,2,2-trifluoroethane CH.sub.2 Cl--CF.sub.3 in a polar aprotic solvent with salts of thiols of the formula RSH, where R can be an alkyl or aryl radical or a heterocyclic radical.

Abstract: The invention relates to a process for the recovery of perfluoroethercarboxylic acids from the crude product of the electrochemical conversion of these acids or of one of their soluble salts to perfluorinated ethers, in which the perfluoroethercarboxylic acids and their esters contained in the crude product are separated off with the aid of a solid basic alkali metal salt or its solution and converted, by reaction of the resulting salts with a strong acid, to the corresponding perfluoroethercarboxylic acids.