Abstract: Salts of polybasic low molecular weight acids are removed from aqueous solutions containing anionic organic compounds by electrodialysis by acidifying the aqueous solution before or during salt removal.

Abstract: Organic sulfonic acids are liberated from aqueous solutions of their salts by a process in which the aqueous organosulfonate solution is subjected to electrodialysis with the aid of an electrodialysis cell which consists of diluate chambers DC, acid chambers AC and base chambers BC according to the sequence I(MB/AC/MA/DC/MK/BC).sub.n Iwhere MB is a bipolar ion exchange membrane, MA is an anion exchange membrane, MK is a cation exchange membrane and n is a number from 1 to 500.

Abstract: Potassium magnesium L-ascorbate 2-phosphate is prepared from an aqueous solution of potassium L-ascorbate 2-phosphate which is highly contaminated with KCl, as is produced in the phosphorylation of 5,6-isopropylidene-L-ascorbic acid, by adding to the solution about 1 equivalent of magnesium ions per equivalent of L-ascorbate 2-phosphate, and subsequently removing the KCl by electrodialysis. The product of this process is a novel salt of L-ascorbic acid 2-phosphate and has very advantageous handling properties.

Abstract: Acid is removed from cathodic electrocoating baths in which electroconductive substrates are being coated with cationic resins present in the form of aqueous dispersions, at least a portion of the coating bath being subjected to an ultrafiltration where the ultrafiltration membrane retains the cationic resin to form an ultrafiltrate which contains water, solvent, low molecular weight substances and ions and is at least partly recycled into the coating bath, by subjecting at least a portion of the ultrafiltrate to a specific electrodialysis treatment before returning it into the electrocoating bath.

Abstract: Acid is removed from cathodic electrocoating baths by a process in which electroconductive sub-strates are coated with cationic resins present in the form of aqueous dispersions, at least a portion of the coating bath being subjected to an ultrafiltration where the ultrafiltration membrane retains the cationic resin to form an ultrafiltrate which contains water, solvent, low molecular weight substances and ions and at least a portion of the ultrafiltrate is recycled into the coating bath, and at least a portion of the ultrafiltrate is subjected to a special electrodialysis treatment before being returned into the electrocoating bath.

Abstract: Salts of polybasic low molecular weight acids are removed from aqueous solutions containing anionic organic compounds by electrodialysis by acidifying the aqueous solution before or during salt removal.

Abstract: A membrane stack unit for performing a multichamber treatment of plural component fluids, composed of a plurality of sealing frames, membranes interposed between the frames, and two end plates with milegrated electrodes disposed at respective opposite ends of the unit with the frames and membranes interposed therebetween. Each frame has four side edges enclosing a region constituting a treatment chamber, with one pair of opposed side edges being provided with a set of through bores for conducting fluid, a set of second bores, and inlet and discharge channels each communicating with a respective second bore and with the chamber, and the second pair of opposed side edges being provided with through bores for conducting fluid. Each membrane is provided with openings aligned with all of the bores. The sealing frames are oriented relative to one another such that at least some of the through bores in one frame are aligned with respective ones of the second bores of another frame.

Abstract: Aqueous glyoxal solutions which contain organic acids are purified by means of a membrane cell comprising two or more compartments by passing the glyoxal solution through at least one of the cell compartments separated from the neighboring compartment(s) by anion exchange membranes and by passing the aqueous solution of a base through at least one of the neighboring compartments.

Abstract: A membrane stack unit for performing a multichamber treatment of plural component fluids, composed of a plurality of sealing frames, membranes interposed between the frames, and two end plates with integrated electrodes disposed at respective opposite ends of the unit with the frames and membranes interposed therebetween. Each frame has four side edges enclosing a region constituting a treatment chamber, with one pair of opposed side edges being provided with a set of through bores for conducting fluid, a set of second bores, and inlet and discharge channels each communicating with a respective second bore and with the chamber, and the second pair of opposed side edges being provided with through bores for conducting fluid. Each membrane is provided with openings aligned with all of the bores. The sealing frames are oriented relative to one another such that at least some of the through bores in one frame are aligned with respective ones of the second bores of another frame.

Abstract: Acid is removed from cathodic electrocoating baths by a process in which electroconductive sub-strates are coated with cationic resins present in the form of aqueous dispersions, at least a portion of the coating bath being subjected to an ultrafiltration where the ultrafiltration membrane retains the cationic resin to form an ultrafiltrate which contains water, solvent, low molecular weight substances and ions and at least a portion of the ultrafiltrate is recycled into the coating bath, and at least a portion of the ultrafiltrate is subjected to a special electrodialysis treatment before being returned into the electrocoating bath.

Abstract: Acid is removed from cathodic electrocoating baths by a process in which electroconductive substrates are coated with cationic resins present in the form of aqueous dispersions, at least a portion of the coating bath being subjected to an ultrafiltration where the ultrafiltration membrane retains the cationic resin to form an ultrafiltrate which contains water, solvent, low molecular weight substances and ions and at least a portion of the ultrafiltrate is recycled into the coating bath, and at least a portion of the ultrafiltrate is subjected to a special electrodialysis treatment before being returned into the electrocoating bath.

Abstract: Aqueous solutions of organic acids or bases are obtained by a process in which(a) an aqueous solution of a salt of an organic acid or of an organic base and(b) respectively, an aqueous solution of an inorganic base or of an inorganic acid are each passed into compartments of an exchange cell which are separated from one another by an ion exchange membrane, and the solution (a) and (b) are transported past the surface of the membrane.

Abstract: The present invention relates to a novel process for removing acids from cathodic electrocoating baths, in which electrically conductive substrates are coated with cationic resins present in the form of aqueous dispersions, part or all of the dip-coating bath being subjected to an ultrafiltration in which the ultrafiltration membrane retains the cationic resin and an ultrafiltrate is formed which contains water, solvent, low molecular weight substances and ions, and part or all of the ultrafiltrate being recycled to the coating bath, in which process(a) part or all of the ultrafiltrate, before recycling to the electrocoating bath and(b) an aqueous solution of an organic or inorganic base, which may or may not contain salts,are each introduced into one or more chambers, separated from one another by an anion exchange membrane, of an exchange cell, solutions (a) and (b) being led over the surface of the membrane.

Abstract: A rolling bellows for pneumatic cushioning or shock absorption of a vehicle. Such rolling bellows are stressed particularly severely during telescoping in the pressureless state during assembly and also under emergency condititions. In order to avoid the occurrence of tension cracks from such causes, the rolling bellows are provided in the region of the cylindrical curvature, and on the inner surface, with integrally formed-on raised surface portions.