Abstract: A process for the preparation of a condensation resin of low catalyst content from a ketone and an aldehyde comprising reacting the ketone and aldehyde in a polycondensation reaction in an aqueous medium in the presence of a basic catalyst to form the resin, which is contaminated with alkali ions from the basic catalyst, and then exposing the resin to an electrical field in a cell demarcated by ion-selective membranes permeable to the alkali ions whereby alkali ions are caused to migrate out of the resin through the membranes. Also, a process for the removal of alkali from condensation resins as described above.

Abstract: Keto compounds are prepared by a condensation reaction in which an enolate is formed, and then a protonation in which the free keto compound is produced. In accordance with the invention, both condensation and protonation are carried out in one step by electrodialysis. Transesterification can also be carried out in the same step.

Abstract: A process for the preparation of keto compounds from the associated alkali metal salts, in which process protonation is carried out by electrodialysis in a nonaqueous medium without the addition of acid which is foreign to the system, and the keto compounds are thereby liberated.

Abstract: The removal of water from aqueous acrylic acid solutions is carried out by removing 10 to 90 wt. % of the water by pervaporation. Subsequent work-up of the acrylic acid by distillation is thereby made easier.

Abstract: A method of manufacturing 2,4-hexadiyne-1,6-diol by the oxidative coupling of propargyl alcohol, in the presence of an aliphatic C.sub.4 alcohol solvent is disclosed. The 2,4-hexadiyne-1,6-diol is completely dissolved in the butanol. Residual salts dissolved in the butanol solution at the end of the reaction are separated out by electrodialysis. The salt-containing stream which is separated out and contains the catalyst salts, water, and butanol is suitable as a reaction mixture, and can be recycled to the reactor.

Abstract: Organic acids are prepared from their salts electrodialytically. At the same time, another acid is converted electrodialytically into the corresponding salt. Both electrodialytic conversions take place in the same electrodialysis unit. If the salt of the organic acid has been fermentatively prepared as, for example, malate from fumarate, it is possible both to prepare malic acid by electrodialysis and also to prepare fumarate from fumaric acid for the fermentation. Through coupling substrate and product streams in the electrodialysis, a closed circuit is formed.

Abstract: The invention relates to a process for purifying polyphenylene oxides obtained by interruption of the copper-amine catalyzed polycondensation of di-ortho-substituted phenols, where in said process the reaction mixture is subjected to a "reaction-extraction" (i.e., an extraction which is accompanied by reaction) with water or stream, at a temperature of 60.degree. to 150.degree. C. It is particularly advantageous if the starting mixture in the inventive process comprises a solution of the polyphenylene oxide wherein the reaction has been interrupted by water and CO.sub.2, which solution is mixed into a toluene/water mixture; and further if the "reaction-extraction" is carried out in the presence of an alkanolamine and a stabilizer.

Abstract: The separation of homozeotropic mixtures of a paraffin or paraffins of 6-14 carbon atoms and an alcohol or alcohols of 4-8 carbon atoms is conducted in two rectification steps. In a first step, rectification is carried out in the presence of water as the azeotropic agent, and the resultant distillate, after condensation, is separated into two liquid phases. The thus-obtained organic phase is rectified in a further step without the addition of water, and the head product consisting of an alcohol/paraffin mixture is recycled into the first step. The paraffin or paraffins and the alcohol or alcohols are obtained in the lower section of the individual rectifying step or steps. The water which may be present in the starting mixture is removed from the cycle. Low-boiling paraffins and/or low-boiling alcohols are suitable as additional azeotropic agents.

Abstract: For the distillation of a stream consisting essentially of alcohols of 6-20 carbon atoms, water and methanol, the methanol is first separated from the homogeneous, aqueous solution as the overhead product by distillation under a head pressure of 500-1,000 mbar. The bottoms discharge is mechanically separated under normal pressure and at a temperature of 5.degree.-95.degree. C. in a phase separator to obtain a discrete water phase preferably containing at least two thirds of the feedstream water. The remaining organic phase is then transferred from the phase separator into a second distillation column and the organic phase is dewatered in the latter at 100-500 mbar. The head product from the second column is conducted to a second phase separator; the aqueous phase is separated therein at a temperature of 5.degree.-95.degree. C. and optionally returned into the first phase separator. The bottom product from the second distillation column is passed into a downstream distillation stage wherein the C.sub.6 to C.

Abstract: A process for recovering propene and propene/propane mixtures from the off-gases obtained from the hydroformylation of propene involves contacting the off-gases with a liquid absorbent comprising at least one of the liquid substances formed during the hydroformylation of propene to absorb the propene and propane and thereafter desorbing these gases from said liquid substances.

Abstract: A method for extracting granular polyamides having at least 10 aliphatically bound carbon atoms per carbonamide group and a method for preparing polyamide powders from the extracted granular polyamides. The granular polyamides are extracted with dimethyl formamide at temperatures between about 70.degree. and 100.degree. C. The extracted granular polyamides are then dissolved in dimethyl formamide and the polyamide powders are formed by cooling the solution.