摘要:
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.
摘要:
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.In the novel process, substituted phenols are obtained in high yields and selectivities, and the catalyst has an extremely long life without a significant decrease in activity.
摘要:
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.
摘要翻译:通过使水杨醛与乙二胺以约2:1的摩尔比和在液体反应介质中的钴盐反应,将烷基化酚氧化成相应的烷基化对苯醌的氧化催化剂改进的改进方法,其中 反应介质是在氮气上二取代的直链或环状的酰胺,特别是二甲基甲酰胺,钴盐是碳酸钴或与钴酸钴2 CoCO 3·3 Co(OH)2·H 2 O. 根据本发明的沙门氏菌素的制备在使用沙门氏菌的情况下,在制备沙门酸本身和随后的三甲基苯酚氧化成三甲基对苯醌时具有显着的优点。
摘要:
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.
摘要:
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. without impairing the yield and purity of the tocopherol opens the way to an advantageous recycling of the zinc halide after the reaction by separating off or extracting and recycling the zinc halide in the form of a from 60 to 90% strength by weight solution or pumpable magma.
摘要:
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.
摘要:
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.
摘要翻译:一种反射柱,其包含具有至少500个滴点/ m 2的液体分配器,其以约90℃的角度布置在紧邻其下方的包装元件的布层; 并结合绝缘和保护加热。 该柱有利地用于需要有效分离效率的高沸点空气或温度敏感物质的混合物的精馏。
摘要:
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. and a cyclic carbonate of the formula II or a &ggr;-lactone of the formula III where R1, R2 and R3 are each H or lower alkyl, and R4 is H, lower alkyl, phenyl or methoxymethyl, as solvent, c) using a nonoxidizing strong inorganic or organic acid, preferably sulfuric acid, boroxalic acid or benzene- or toluenesulfonic acids, in catalytic amounts as acid catalyst, and d) continuously removing the water formed in the reaction by azeotropic distillation during the reaction.
摘要:
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.
摘要:
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.