Abstract: A process for the preparation of 2-hydroxynaphthalene-6-carboxylic acid using potassium carbonate and CO at temperatures above 260.degree. C. and at a pressure of at least 10 bar comprises using 2-hydroxynaphthalene-3-carboxylic acid and/or 2-hydroxynaphthalene-3,6-dicarboxylic acid and/or their potassium salts and, if desired, potassium .beta.-naphtholate as starting materials.The process according to the invention enables a considerable increase, by reusing the secondary products, in the product selectivity with regard to 2-hydroxy-naphthalene-6-carboxylic acid.

Abstract: A process for the preparation of aromatic hydroxy carboxylic acids by reacting alkali metal phenolates or alkali metal naphtholates with alkali metal carbonates and carbon monoxide, with subsequent acidification, wherein the solid starting materials--alkali metal carbonate and/or alkali metal phenolate or naphtholate--are metered into the reaction mixture in the form of one or more dispersions in an inert organic liquid.The process according to the invention enables the preparation of aromatic hydroxy carboxylic acids in good yields and with high chemical selectivity. Additional measures for increasing the selectivity, as described for example for the Kolbe-Schmitt reaction in EP-A 0 053 824, EP-A 0 081 753 and EP-A 0 254 596, and for the reaction with CO and carbonate in, for example, WO 91/11422, are unnecessary.

Abstract: This invention embodies a process for releasing acidic organic compounds in high yield and good purity from aqueous solutions of their salts which comprises converting the salts by carbon dioxide to their corresponding free acidic organic compounds and metal hydrogen carbonates, removing the acidic organic compounds from the mixture by extraction with an essentially water-insoluble organic solvent, and re-extracting the organic phase with carbon dioxide containing water. Using this process, the acidic organic compounds are completely released from their corresponding salts, i.e., the organic solution is free of salt. The acidic organic compounds released by the claimed process are organic compounds which contain acidic protons which can be replaced by metals. Some examples are carboxylic acids, sulfonic acids, phosphonic acids, phenols, naphthols, and aliphatic alcohols.

Abstract: A process for preparing aromatic hydroxycarboxylic acids or di-salts thereof by reaction of alkali metal phenolates or naphtholates with carbon dioxide, in the presence or absence of a further alkali metal salt, which comprises introducing the solid phenolate or naphtholate starting materials and, if desired, the alkali metal salt into the reaction mixture batchwise or continuously, separately or together, in the form of a dispersion in an inert organic liquid.The process of the invention makes possible the preparation of aromatic hydroxycarboxylic acids in good yields and with high chemical selectivity. Additional measures for increasing the selectivity, as are described for the Kolbe-Schmitt reaction in, for example, EP-A 0 053 824, EP-A 0 081 753 and EP-A 0 254 596, can be omitted.

Abstract: Process for separating and purifying substances by crystallization from the melt under high pressuresIn the process for separating or purifying substances by crystallization from melts or highly concentrated solutions under high pressures, gas is dissolved in the melt to be crystallized and is expelled again after the crystallization with reduction in the pressure. Still adhering or occluded impurities are thus removed.

Abstract: In the process for separating and purifying substances by crystallization from the melt under pressure, the melt is subjected to pressure under an inert gas atmosphere and then cooled, whereupon it crystallizes. The residual melt is separated from the resulting crystals, after which the crystals are degassed by reducing the pressure and are caused to sweat, and the sweat oil is separated off.

Abstract: The present invention relates to a process for purifying fatty acid amides, which contains the following process steps:neutralization of the fatty acid by addition of an aqueous alkaline solution andsubsequent distillation of the neutralized mixture.

Abstract: In the process for the preparation of pure trioxane by continuous or semicontinuous crystallization processes, if alkaline organic compounds are added no flocks appear after more than 120 hours of operation. As a result, blockage of the crystallization unit is prevented and problem-free running is made possible.

Abstract: 2-Hydroxy-naphthalene-6-carboxylic acid or its dipotassium salt is obtained in a good yield and purity without substantial formation of the isomeric compound 2-naphthol-3-carboxylic acid by reacting potassium .beta.-naphtholate with potassium carbonate in the presence of carbon monoxide at a temperature above 260.degree. C. in potassium formate as the solvent.

Abstract: An ordered packing for mass transfer and heat exchange processes includes pre-formed individual parts. The packing is formed of carbon fiber-reinforced carbon with carbon fibers or carbon fiber yarns, which are linked one with the other by way of textile bindings, as a filler and of a matrix carbon, preferably based on synthetic resins.

Abstract: 2-(4-Isobutylphenyl)-propionic acid is purified by subjecting it to a vacuum rectification, in which the temperature is below the decomposition temperature of the acid.

Abstract: A process for separating m- and p-dichlorobenzene by extractive rectification with an extractant and removal of this extractant. Using as extractant an alkylene carbonate of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical to or different from one another and each is hydrogen, methyl or ethyl, with the proviso that together the radicals R.sup.1 to R.sup.4 do not contain more than 6 carbon atoms.The process of the invention makes it possible to separate off the m-isomer in high purity.

Abstract: The present invention relates to a process for the purification of 4-acetoxystyrene from a crude product mixture comprising 4-acetoxystyrene and typically 5 or more contaminants in substantial amount.The crude product mixture is purified by melt crystallization by cooling the mixture to a temperature ranging from about +8.degree. C. to about -50.degree. C., whereby at least a first portion of the mixture is crystallized; removing the liquid remaining from contact with the crystallized first portion of the mixture; and, subsequently slowly heating the crystallized first portion, while simultaneously removing liquid which forms due to the heating, whereby impurities contained in the liquid which forms are removed from the crystallized first portion.Surprisingly, despite the large number of contaminants present, and use of the process to purify crude product mixtures containing as little as 50% by weight 4-acetoxystyrene, purities as high as 99.

Abstract: The invention relates to the dioxane adducts of armoatic meta-or para-hydroxycarboxylic acids, which consist, per mole, of 1 mole of 1,4-dioxane and about 2 moles of hydroxycarboxylic acid. The invention further relates to a process for the preparation of these adducts, which comprises dissolving the hydroxycarboxylic acids in dioxane or a mixture of the latter with water or with an organic solvent and then allowing the adducts to crystallize.

Abstract: The invention relates to the dioxane adduct of 2-hydroxynaphthalene-6-carboxylic acid which adduct comprises 1 mol of 1,4-dioxane and about 2 mol of 2-hydroxynaphthalene-6-carboxylic acid per mol. The invention further relates to a process for the preparation of this adduct, wherein the 2-hydroxynaphthalene-6-carboyxlic acid is dissolved in dioxane or a mixture thereof with water or with an organic solvent and then allowed to crystallize.

Abstract: The invention relates to a process for the separation and recovery of naphthalenesulfonic acids from aqueous solutions. In this, the naphthalenesulfonic acids are adsorbed on basic ion exchangers and subsequently desorbed again, preferably with the aid of an alkaline liquor, from which the alkali metal sulfonates are then precipitated by cooling.

Abstract: The invention relates to a gentle process for the separation of enol ethers from mixtures containing water-soluble alcohols by extraction, wherein an aqueous solution of a base is used as the extraction agent in a phase ratio of the amounts of the aqueous phase: enol ether/alcohol mixture of at least 0.5:1 and the extraction is carried out in several stages or continuously with a theoretical number of stages of at least two. The process is particularly suitable for separating off enol ethers which readily decompose during distillation.

Abstract: The invention relates to the dioxane adduct of 2-hydroxynaphthalene-6-carboxylic acid which adduct comprises 1 mol of 1,4-dioxane and about 2 mol of 2-hydroxynaphthalene-6-carboxylic acid per mol. The invention further relates to a process for the preparation of this adduct, wherein the 2-hydroxynaphthalene-6-carboxylic acid is dissolved in dioxane or a mixture thereof with water or with an organic solvent and then allowed to crystallize.

Abstract: A process for the separation of undesired organic ingredients from waste gases which are formed in the preparation of aromatic intermediates which comprises washing the waste gases with a washing liquid comprising(a) paraffinic hydrocarbons having from 10 to 20 carbons atoms or(b) diisopropylnaphthalene or a mixture of isomers thereof having the sum formula C.sub.16 H.sub.20, an average molecular weight in the range of from 210 to 215, a boiling range in the range of from 290 to 300.degree. C. (according to DIN 51 761) and a flash point above 130.degree. C. (according to DIN 51 758).at a temperature in the range of from 0 to 50.degree. C. to remove the said undesired organic ingredients.

Abstract: The invention relates to a process for the preparation of pure cis- or trans-crotonic acid from a mixture of the two isomers by melt crystallization. To prepare trans-crotonic acid, an isomer mixture I containing at least 40% by weight of trans-crotonic acid is used as the starting material. On the other hand, if cis-crotonic acid is to be prepared, an isomer mixture II containing at least 80% by weight of cis-crotonic acid is used as the starting material. The particular isomer mixture is melted and then left to cool, trans-crotonic acid being allowed to crystrallize out of mixture I to a residual content of at least 35% by weight, and cis-crotonic acid being allowed to crystallize out of mixture II to a residual content of at least 75% by weight.