Abstract: The invention relates to a process for the preparation of novolak resins having a low amount of metal ions. In the process, a conventional resin in an organic solution is brought into contact with an acidic, preferably complex-forming compound which preferably is present in an aqueous phase. The resin solutions may be used in the production of photoresists.

Abstract: The invention relates to a process for separating N-methyl-2-pyrrolidone (NMP) from aqueous solutions which are obtained in industry, inter alia, in the production of heat-resistance polymers such as polyamides and polyimides.According to the invention, the extractants used are phenols which are sparingly soluble in water, are aliphatically monosubstituted and/or polysubstituted in the nucleus and have 4 to 16 carbon atoms in the straight-chain or branched, saturated or unsaturated aliphatic radical and have a boiling point which is preferably at least 20.degree.-25.degree. C. above the boiling point of NMP. If necessary, an inert, viscosity-reducing diluent is added.

Abstract: A process is disclosed for the separation of halogenated hydrocarbons from concentrated hydrochloric acid, which contains 10 to 37% by weight of hydrogen chloride. The hydrochloric acid is freed from the halogenated hydrocarbons in an extraction with paraffins having more than 7 carbon atoms, or with paraffin waxes having dropping points from 70.degree. to 160.degree. C. or with paraffin/paraffin wax mixtures, preferably in a continuous counterflow extraction or cross-flow extraction.

Abstract: The invention relates to a process for extracting halogenated hydroxyaromatics from aqueous solutions. In this process, the extractant used is an amine salt comprising an aliphatic amine having a total carbon number of 10 to 75 and a strong acid. The amine salt may be employed in undiluted form or diluted with an organic solvent.

Abstract: The invention relates to a process for extracting nitrohydroxyaromatics from aqueous solutions. In this process, the extracting agent used is an amine salt which comprises an aliphatic amine having a total carbon number of 10 to 75 and a strong acid. The amine salt can be employed undiluted or diluted with an organic solvent.

Abstract: The invention relates to a process for the extraction of carboxylic acids from aqueous solutions with a carboxylic acid content below 8% by weight. A mixture of an aliphatic amine with a total carbon number of at least 10 and a phenol or naphthol is used as extracting agent. The molar ratio of phenol:amine or alkylated phenol:amine or naphthol:amine is in the range from 0.1:1 to around 1.1:1.

Abstract: The invention relates to a process for extracting phenols from aqueous solutions. The extractant used is a salt of an aliphatic amine, having a total carbon number of at least 10, and a strong acid.

Abstract: Glycidyl ethers of monohydric or polyhydric phenols of high purity are obtained if hydrogen halide is eliminated from halohydrin ethers of the phenols in aqueous alkalis in the presence of one or more onium compounds selected from quaternary ammonium compounds having at least one aliphatic C.sub.4-22 hydrocarbon radical, quaternary phosphonium compounds and tertiary sulphonium compounds as catalyst, or in the presence of those compounds which form in the reaction medium in situ, before the addition of the alkali, such onium compounds from the halohydrin ethers together with tertiary amines, tertiary phosphines or thioethers. In comparison with the known processes, the rate of dehydrohalogenation can thereby be significantly increased as a result of which an increase in production is achieved. Moreover, significantly purer reaction products are obtained by the avoidance of side reactions.

Abstract: Contaminated phosphoric acid, particularly wet-processed phosphoric acid, is purified by extracting it from its aqueous solution by means of an organic solvent, which is immiscible or partially miscible with water and in which phosphoric acid is soluble, separating the phosphoric acid being dissolved in the organic solvent from extraction residue, and recovering the phosphoric acid from the organic solution.The aqueous phosphoric acid is more particularly mixed in a reaction zone, in a ratio by volume within the range 1:0.3 to 1:30, with a solvent having a boiling point higher than that of water or higher than that of the resulting water solvent-azeotrope, the phosphoric acid/solvent-mixture is heated to temperatures between the boiling point of water or of the said azeotrope and that of the solvent until distillation of substantially all uncombined water originally present in the mixture, and residue and resulting anhydrous phosphoric acid solution in the organic solvent are separated.

Abstract: Phosphoric acid is purified. To this end, it is dissolved in an organic solvent completely miscible with water. More particularly, the phosphoric acid is mixed with a solvent having a boiling point higher than that of water or higher than that of the resulting azeotrope; the resulting solution is heated to temperatures between the boiling point of water or the azeotrope and that of the solvent for as long a period as necessary to distillatively free the solution from the bulk of uncombined water therein; and the phosphoric acid solution is separated from residue.