Abstract: A process for preparing or regenerating peroxodisulfuric acid and its salts by electrolysis of an aqueous solution containing sulfuric acid and/or metal sulfates at diamond-coated electrodes without addition of promoters is described, with bipolar silicon electrodes which are coated with diamond on one side and whose uncoated silicon rear side serves as cathode being used.

Abstract: A process for preparing or regenerating peroxodisulfuric acid and its salts by electrolysis of an aqueous solution containing sulfuric acid and/or metal sulfates at diamond-coated electrodes without addition of promoters is described, with bipolar silicon electrodes which are coated with diamond on one side and whose uncoated silicon rear side serves as cathode being used.

Abstract: In a method for desalting aqueous solutions by means of electrodialysis in an electrochemical cell (10) comprising a first electrode (16) and a second electrode (20), wherein the second electrode (20) has a polarity opposite to the first electrode and wherein at the first electrode (16) an electrolysis gas and ions are formed, it is proposed that the electrolysis gas and the ions are reacted at the second electrode (20).

Abstract: A process for preparing or regenerating peroxodisulfuric acid and its salts by electrolysis of an aqueous solution containing sulfuric acid and/or metal sulfates at diamond-coated electrodes without addition of promoters is described, with bipolar silicon electrodes which are coated with diamond on one side and whose uncoated silicon rear side serves as cathode being used.

Abstract: The object of this invention is a moisture-curing, storage stable, single-component polyurethane system comprising:A. a polyurethane prepolymer with a free isocyanate content of 1 to 5 percent by weight;B. a dialdimine having the formulaR[--N.dbd.CH--C(CH.sub.3).sub.2 --CH.sub.2 --O--CO--CH--(CH.sub.3).sub.2 ].sub.2in whichR is a divalent aliphatic radical with 2 to 10 carbon atoms, aliphatic radical having 4 to 10 carbon atoms and containing ether oxygen and/or lower alkylamino nitrogen atoms, cycloaliphatic radical with 6 to 15 carbon atoms oraromatic radical with 6 to 21 carbon atoms;andC. an acid catalyst selected from the group consisting of aliphatic carboxylic acids, aromatic carboxylic acids, toluenesulfonic acid, and mixtures thereof.The polyurethane systems are used as coating, sealing, casting, spackling and bonding materials.

Abstract: .alpha.-Alkylacroleins are prepared by reacting an alkanal with formaldehyde and a secondary amine in the presence of a carboxylic, dicarboxylic or polycarboxylic acid in certain molar ratios within a pH range of from 2.5 to 7 and at from 0.degree. to 150.degree. C.The .alpha.-alkylacroleins which can be prepared by the process described are valuable starting materials for dyes, drugs and pest control agents.

Abstract: 3-Hydroxy-2,2,4-trimethylpentyl isobutyrate is prepared by reaction of isobutyraldehyde in the presence of an alkaline earth metal hydroxide and of carboxylic acids or the corresponding salts, under specific conditions in respect of reaction time and proportion and concentration of the hydroxide suspension. The product is a starting material for the preparation of dyes, pesticides, adhesives and surface coatings.