Abstract: The present invention relates to a process for preparing quaternary phosphonium salts by reacting a ternary phosphine with an optionally substituted, saturated or monounsaturated or polyunsaturated electrophile having from 3 to 25 carbon atoms in ternary solvent mixtures.

Abstract: The present invention relates to a process for preparing vitamin A acetate by reacting ?-vinylionol with triphenylphosphine in the presence of sulfuric acid in a solvent mixture consisting of 60 to 80% by weight methanol, 10 to 20% by weight water and 10 to 20% by weight aliphatic, cyclic or aromatic hydrocarbons having 5 to 8 carbon atoms to give ?-ionylideneethyltriphenylphosphonium salts and subsequent Wittig reaction with 4-acetoxy-2-methylbut-2-enal.

Abstract: The present invention relates to a process for preparing quaternary phosphonium salts by reacting a ternary phosphine with an optionally substituted, saturated or monounsaturated or polyunsaturated electrophile having from 3 to 25 carbon atoms in ternary solvent mixtures.

Abstract: The present invention relates to a process for preparing vitamin A acetate by reacting ?-vinylionol with triphenylphosphine in the presence of sulfuric acid in a solvent mixture consisting of 60 to 80% by weight methanol, 10 to 20% by weight water and 10 to 20% by weight aliphatic, cyclic or aromatic hydrocarbons having 5 to 8 carbon atoms to give ?-ionylideneethyltriphenylphosphonium salts and subsequent Wittig reaction with 4-acetoxy-2-methylbut-2-enal.

Abstract: A method for processing a vitamin E acetate-containing product stream, which comprises

Abstract: A process is described for continuously preparing chromanol ester derivatives, in particular for continuously preparing carboxylic esters of tocopherols and tocotrienols by continuous acylation with carboxylic acids or carboxylic anhydrides.

Abstract: A process is described for continuously preparing chromanol ester derivatives, in particular for continuously preparing carboxylic esters of tocopherols and tocotrienols by continuous acylation with carboxylic acids or carboxylic anhydrides.

Abstract: A reflection column which contains liquid distributors having at least 500 drip points/m2, which are arranged at an angle of about 90° C. to cloth layers of packing elements located immediately therebelow; and a combination of insulation and protective heating. The column is advantageously used for the rectification of mixtures of high-boiling air- or temperature-sensitive substances requiring effective separation efficiency.

Abstract: A process for preparing tocopheryl esters or tocotrienyl esters by acid-catalyzed esterification of a tocopherol or a tocotrienol in a solvent while stirring at elevated temperature, which comprises a) carrying out the esterification with the appropriate carboxylic acid, b) carrying out the esterification with from 2.5 to 6 mol of the carboxylic acid in an aliphatic, cycloaliphatic or aromatic hydrocarbon boiling in the range from 80 to 200° C., or else with from 1.0 to 2.5 mol of the carboxylic acid in a mixture consisting of an aliphatic or cycloaliphatic hydrocarbon boiling in the range from 80 to 200° C.

Abstract: Process for isolating pure substances from of mixtures of high-boiling air- and/or temperature-sensitive substances which require a high separation efficiency, by rectification under medium vacuum in columns containing metal cloth packings with ordered structure using channel liquid distributors with 500 or more drip points/m.sup.2, which are arranged at an angle of 90.degree. to the cloth layers of the packing elements located immediately below the distributors, in which two or more of the packing elements underneath the liquid distributors have only a very small height, which ensure virtual exclusion of air and are designed so that no heat exchange through the column wall can take place during the rectification. The patent also relates to packed columns which can be used for this process and to the use of this process and these columns for the final purification of vitamin E acetate by distillation.

Abstract: A process for preparing .alpha.-tocopherol or .alpha.-tocopheryl acetate by reacting 2,3,5-trimethylhydroquinone with isophytol or phytol in the presence of a zinc halide condensation catalyst and a proton donor in a solvent with or without subsequent esterification with acetic anhydride, which comprisesA. carrying out the reaction in a nonpolar solvent which is only slightly water-miscible, if at all andB. introducing the required zinc halide into the reaction in the form of a mixture of from 1 to 4 mol of water per mol of zinc halide.The possibility of introducing the zinc halide required in the process according to the invention in the form of a mixture of zinc halide and water which can be readily handled and metered at from 50 to 200.degree. C.

Abstract: Packing elements with a low pressure drop for mass transfer column internals of the internal diameter of the column and of a height of from 40 to 300 mm made of dimensionally stable layers, which have an ordered structure and are in mutual contact, of cloth material or cloth-like material with a specific surface area of from 100 to 2000 m.sup.2 /m.sup.3, whereina) the shaped layers of cloth material or cloth-like material, preferably made of metal cloth, which are in mutual contact are arranged so that they form a multiplicity of narrow flow channels, preferably virtually triangular, virtually rectangular or else virtually equilateral hexagonal flow channels, in which the angle of inclination of the serration of the individual cloth layers of the packing to the column axis is only 0 to 25.degree., preferably 3 to 14.degree.

Abstract: 2,3,5-Trimethyl-p-benzoquinone is prepared by oxidation of trimethylphenol with oxygen or an oxygen-containing gas in the presence of a catalyst containing a copper(II) halide in a two-phase reaction medium consisting of water and an aliphatic alcohol at elevated temperatures by a process in which the reaction is carried out in a mixture of water and a saturated aliphatic alcohol of 12 to 18 carbon atoms, having a flashpoint greater than 120.degree. C., such as 1-dodecanol, 1-tetradecanol, 1-hexadecanol or 1-octadecanol, in particular 1-dodecanol, and at from 60.degree. to 100.degree. C.Particularly good yields of TMQ are obtained if the reaction is carried out in the presence of a copper(II) halide, such as CuCl.sub.2 or CuBr.sub.2, and of an alkaline earth metal halide, in particular CaCl.sub.2 or MgCl.sub.2, or of an alkali metal halide, in particular LiCl or NaCl, as the catalyst system.

Abstract: The yield of 2,5,6-trimethyl-cyclohex-2-en-1-one is increased by reacting diethyl ketyone, in the presence of an alkali, with crotonaldehyde or a compound which is converted to crotonaldehyde under the reaction conditions chose, and working up the reaction mixture by distillation, by a method in which the distillation residue obtained is either(a) heated at from 120.degree. to 250.degree. C. in particular from 120.degree. to 200.degree. C., with the addition of a catalytic amount of an alkali, or(b) heated at from 150.degree. to 250.degree. C. without the addition of such a substance,and the mixture of 2,5,6-trimethylcyclohex-2-en-1-one and diethyl ketone which is formed from the distillation residue as a result of the heat treatment is separated by distillation.

Abstract: 2,3,6-Trimethylhydroquinone is prepared by catalytic hydrogenation of 2,3,6-trimethylquinone with hydrogen in the presence of a solvent by a continuous process in which the reaction is carried out over a platinum/alumina catalyst.

Abstract: Improved process for the preparation of salcomine useful as an oxidation catalyst for the oxidation of alkylated phenols to the corresponding alkylated p-benzoquinones by reacting salicylaldehyde with ethylenediamine in a mole ratio of about 2:1 and a cobalt salt in a liquid reaction medium wherein the reaction medium is a linear or cyclic carboxamide which is disubstituted on the nitrogen, in particular dimethylformamide, and the cobalt salt is cobalt carbonate or with the cobalt hyroxide carbonate, 2 CoCO.sub.3.3 Co(OH).sub.2.H.sub.2 O. Preparation of the salcomine in accordance with the invention offers significant advantages, both in the preparation of the salcomine itself and in the subsequent oxidation of the trimethylphenol to trimethyl-p-benzoquinone utilizing the salcomine.

Abstract: Substituted phenols of the general formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each hydrogen or an aliphatic or aromatic hydrocarbon radical, are prepared by dehydrogenating a cyclic alcohol of the general formula II ##STR2## or a cyclic ketone of the general formula III ##STR3## where one of the broken lines can be an additional C-C bond, in the gas phase at from 150.degree. to 380.degree. C. over a supported noble metal catalyst, by a process in which the dehydrogenation catalyst used is palladium or platinum on an aluminum spinel carrier, in particular an aluminum spinel which has a BET specific surface area of from 5 to 150 m.sup.2 /g or, for the dehydrogenation of cyclohexenones, preferably from 10 to 50 m.sup.2 /g. Particularly suitable aluminum spinels are those which, in addition to aluminum, contain magnesium, zinc, cobalt or nickel.

Abstract: In a process for the preparation of a carboxylic acid ester of .beta.-formyl-crotyl alcohol by rearrangement of the corresponding carboxylic acid ester of 2-formyl-2-hydroxy-but-3-ene or of an acetal or acylate thereof in the presence of copper or a copper compound, followed, where relevant, by hydrolytic cleavage of the acetal or acylate, more especially in the preparation of 4,4-dimethoxy-3-methyl-crotyl acetate, the yield is improved by carrying out the rearrangement in the presence of copper (I) chloride as the catalyst and ensuring that low-boiling by-products formed during the rearrangement are removed.The products are of great importance as starting materials for an industrial synthesis of vitamin A and its derivatives.

Abstract: A process for the preparation of an indolenine of the formula ##STR1## where R, X and Y are conventional substituents, by thermal rearrangement of a compound of the formula ##STR2## to give a compound of the formula ##STR3## and cyclization of this compound in the presence of an acid catalyst.

Abstract: A process for the preparation of an indolenine of the general formula I ##STR1## where R, R.sup.1 and R.sup.2 are aliphatic radicals and R.sup.1 and R.sup.2 may also be linked and the ring A may be additionally substituted, wherein a compound of the formula II ##STR2## is heated in the presence of a Lewis acid and of a halide. The products are valuable starting compounds for the preparation of dyes.