摘要:
The invention relates to an improved method for releasing an organic acid, preferably a carbon, sulfone or phosphone acid, particularly an alpha or beta hydroxycarbon acid, from the ammonia salt thereof by releasing and removing ammoniac and simultaneous extraction of the released acid, having an amine as a suitable extraction means from the aqueous phase. This method corresponds to a reactive extraction. The reactive extraction of an organic acid from the aqueous ammonia salt solution thereof can be significantly improved by the use of a strip medium or carrier gas, such as nitrogen, air, water vapor or inert gases such as argon. The released ammoniac is removed from the aqueous solution by the continuous gas flow and can be resupplied into a production process. The free acid can be obtained by a method such as distillation, rectification, crystallization, reextraction, chromatography, adsorption or by a membrane method from the extraction means.
摘要:
A process for the preparation of free carboxylic acids including: A) preparation of carboxylic acid by a biological cell located in an aqueous medium with addition of an amine of formula (I) where R1, R2 and R3, independently of one another, are identical or different, branched or unbranched, optionally substituted hydrocarbon radicals or H; B) for cases where the added amine A) is water-soluble, addition of a water-insoluble amine of formula (I), where, in A) or B), a multiphase system is obtained and the corresponding ammonium carboxylate is formed from the water-insoluble amine and the carboxylic acid; C) removal of the water-insoluble phase; and D) heating of the water-insoluble phase with release of free carboxylic acid.
摘要:
A catalyst for the dehydrogenation of C6.sub.6 -C.sub.15 paraffins is disclosed. The catalyst contains, on a support, at least one platinum group component, at least one promoter component from the group tin, germanium and lead, and at least one additional modifier. The additional modifier contains at least one alkaline earth metal. The stability of the catalyst is essentially higher than that achieved by conventional use of an alkali metal.
摘要:
A process is disclosed for the selective catalytic hydrogenation of carbonyl groups in aromatic aldehydes of the formula: ##STR1## in which X is carboxyl, methyl or a halogen, to give the corresponding alcohols and methyl compounds. The catalytic hydrogenation is performed with the addition of a solvent optionally in the presence of organic acids on a shaped support catalyst containing a platinum group metal on a support made from titanium oxide in the presence of hydrogen at hydrogen partial pressures of 5 to 50 bar and temperatures of 100.degree. to 300.degree. C.
摘要:
Moldings based on pyrogenically produced mixed oxide having the following physicochemical parameters: External diameter 0.8-25 mm BET surface area 5-400 m2/g Pore Volume 0.2-1.8 ml/g Fracture strength 5 to 350 N Composition At least two oxides selected from the group SiO2, Al2O3, TiO 2 and ZrO2 in any desired combination but with the exception of SiO2/Al2O3 mixed oxides, in which > 75 wt. % of SiO2 is present. Other constituents
摘要:
Moldings based on silica having a hollow cylindrical configuration with internal reinforcing stays or spokes leading from an inner wall of a hollow cylinder to the center of the molding or in the form of miniliths having passageway channels therethrough, are produced by homogenizing silica with methyl hydroxyethyl cellulose, wax and/or polyethylene glycol. Water and optionally aqueous alkaline ammonia solution are added, and the mixture is subjected to kneading and forming, extruding, optionally cutting the extrudate to the desired length by means of a cutting device, drying at a temperature from 20 to 150° C., and annealing for a period from 30 minutes to 10 hours at a temperature of 400 to 1200° C. The moldings can be used as catalyst supports for the production of unsaturated esters from olefins, organic acids and oxygen in the gas phase and and can be used in particular for the production of vinyl acetate monomer.
摘要:
Process for the selective hydrogenation of alphatic or aromatic substrates under supercritical or near critical conditions. Hydrogenation is effected using a heterogeneous catalyst in a continuous flow reactor containing a supercritical or near critical reaction medium and selectively of product formation is achieved by varying one or more of the temperature, pressure, catalyst and flow rate.
摘要:
The present invention is relative to a method of producing dry thioctic acid in which a raw material in which concentrated thioctic acid is present is treated with liquid or supercritical CO.sub.2, thus yielding thioctic acid with low residual solvent contents in a simple industrial method.
摘要:
Method of performing alkylation or acylation reactions of aromatic substrates under supercritical or near-critical reaction conditions. In particular, a method of performing Friedel-Crafts alkylation or acylation reactions is disclosed under those conditions. Friedel-Crafts reactions may be effected using a heterogeneous catalyst in a continuous flow reactor containing a super-critical or near-critical reaction medium. Selectivity of product formation can be achieved by varying one or more of the temperature, pressure, catalyst, flow rates and also by varying the ratios of aromatic substrate to acylating or alkylating agent.