摘要:
A process for producing solids by precipitation in a mixer to form a mixture of solid and liquid, where the starting materials are fed into a mixing apparatus which has essentially a rotationally symmetrical mixing chamber which has a rotor disposed therein and is formed by a peripheral wall and two end walls, and where a) the starting materials are each fed to at least one inlet opening in the peripheral wall of the mixing chamber, and b) the solid-containing mixture which is formed is removed from at least one outlet opening in the peripheral wall of the mixing chamber.
摘要:
Process for the continuous preparation of unsaturated ketones of the formula I where the dashed line can be an additional C—C bond, R1 is an alkyl, and R2 is an aliphatic hydrocarbon having from 1 to 37 carbons, a cycloalkyl or a cycloalkylalkyl, by reacting an unsaturated alcohol of the formula II with an alkyl acetoacetate of the formula III where R3 is an alkyl having from 1 to 5 carbons, in the presence or organic aluminum compounds as catalyst.
摘要:
Catalytic reactions are carried out in a reactor which contains a liquid phase in which at least one catalyst is suspended, and which may additionally contain a gas phase, by a process in which the liquid phase and, if present, also the gas phase are fed, at least partly, through an apparatus having orifices or channels in the reactor, the hydraulic diameter of which orifices or channels is from 0.5 to 20 mm, preferably from 1 to 10 mm, particularly preferably from 1 to 3 mm.
摘要:
Alkenes are prepared by partial hydrogenation of alkynes in the liquid phase over palladium catalysts by a process which comprises A. using a fixed-bed catalyst which is obtainable by heating the preferably metallic carrier in the air, cooling, coating under reduced pressure with metallic palladium, suitable molding and processing to a monolithic catalyst elements and B. adding from 10 to 180 ppm of CO to the hydrogen used for the hydrogenation.
摘要:
A process for preparing at least one unsaturated alcohol (B) comprises the steps (I) to (III) below: (I) reaction of at least one alkali metal hydroxide or alkaline earth metal hydroxide with at least one alcohol (A) in at least one organic solvent (L) to give a mixture (G-I) comprising at least the alcohol (A), the solvent (L) and an alkoxide (AL); (II) reaction of at least one carbonyl compound of the formula R—CO—R′ with at least one alkyne of the formula R″—C≡C—H and the mixture (G-I) obtained in step (I) to give a mixture (G-II) comprising at least the alcohol (A), the solvent (L) and an unsaturated alcohol (B); (III) distillation of the mixture (G-II) obtained in step (II) to give the alcohol or alcohols (B) and a mixture (G-III) comprising the solvent (L) and the alcohol (A), wherein the solvent (L) obtained in step (III) and the alcohol (A) obtained in step (III) are recycled as a mixture to step (I).
摘要:
A structured packing for heat exchange and mass transfer between a liquid and a gas in a column having at least one packing layer with a first, lower end and a second, upper end is described, the packing layer having an internal geometry which varies over its height so that by suitably setting the liquid and gas flow rates in a first, in particular lower, region of the packing layer a bubbling layer having a predominantly disperse gas phase forms in a targeted manner and simultaneously in a second, in particular upper, region of the packing layer a film flow of the liquid having a predominantly continuous gas phase forms in a targeted manner.
摘要:
Alkenes are prepared by partial hydrogenation of alkynes in the liquid phase at from 20 to 250° C. and hydrogen partial pressures of from 0.3 to 200 bar over fixed-bed supported palladium catalysts which are obtainable by heating the support material in the air, cooling, applying a palladium compound and, if required, additionally other metal ions for doping purposes, molding and processing to give monolithic catalyst elements, by a process in which A) alkynes of 10 to 30 carbon atoms are used as starting compounds, B) the palladium compound and, if required, the other metal ions are applied to the support material by impregnation of the heated and cooled support material with a solution containing palladium salts and, if required, other metal ions and subsequent drying, and C) from 10 to 2000 ppm of carbon monoxide (CO) are added to the hydrogenation gas or a corresponding amount of CO is allowed to form in the liquid phase by slight decomposition of a compound which is added to the reaction mixture and eliminates CO under the reaction conditions. The process is particularly advantageous if the partial hydrogenation is carried out in a tube reactor by the trickle-bed or liquid phase procedure with product recycling at cross-sectional loadings of from 20 to 500 m3/m2*h. The process is particularly suitable for the preparation of 3,7,11,15-tetramethyl-1-hexadecen-3-ol (isophytol), 3,7,11-trimethyl-l-dodecen-3-ol (tetrahydronerolidol), 3,7,11-trimethyl-1,4-dodecadien-3-ol, 3,7,11-trimethyl-1,6-dodecadien-3-ol (dihydronerolidol), 3,7-dimethyloct-1,6-dien-3-ol or 3,7-dimethyloct-1-en-3-ol from the corresponding alkynes.
摘要:
Process for the continuous preparation of &agr;- and/or &bgr;-ionone or homologous compounds using concentrated sulfuric acid at temperatures from 20 to 90° C., in the presence of organic solvents or diluents with cooling and by subsequent termination of the reaction by hydrolysis of the reaction mixture with water or dilute sulfuric acid, wherein both the cyclization of pseudoionones and the subsequent hydrolysis of the reaction mixture are carried out in a virtually adiabatic reaction in one or more reaction mixing pump(s) which are connected in series and each of which consists essentially of a rotationally symmetrical mixing chamber formed from a peripheral wall and two end walls and of a mixing rotor made of material inert to sulfuric acid and with rotational drive, where the mixing chamber has at least one inlet opening for each component and one outlet opening for the reaction mixture, and annular channels in fluid connection to one another in the end walls, and wherein the heat of the two reactions is in each case partly or wholly removed with the aid of a downstream heat exchanger.
摘要:
A process for preparing .gamma.,.delta.-unsaturated ketones of the general formula I ##STR1## by reacting an allyl alcohol of the general formula II ##STR2## in which R.sup.1 is H or a hydrocarbon radical having 1 to 20 carbon atoms, with diketene or an alkyl acetoacetate of the general formula III ##STR3## in which R.sup.2 is alkyl having 1 to 4 carbon atoms in an unmodified or modified Carroll reaction in the presence of an aluminum catalyst, wherein aluminum compounds which are stable liquids at room temperature, or a mixture of such aluminum compounds, which comprise at least one radical formed from an alkyl acetoacetate and 1 or 2 alkoxy radicals, or else comprise exclusively radicals formed from alkyl acetoacetates, which are esterified with sec-butanol or isobutanol, or else are esterified with at least two different alcohols, are used as aluminum catalyst. Also claimed are the novel mixtures of aluminum compounds which comprise radicals which are formed exclusively from alkyl acetoacetates and are esterified with at least two different alkanols, and the batchwise and continuous preparation of the liquid aluminum catalysts.
摘要:
A process for preparing 2,5,6-trimethyl-2-cyclohexen-1-one by reacting diethyl ketone with crotonaldehyde or a compound which is converted under the chosen reaction conditions into crotonaldehyde, in the presence of basic agents at elevated temperature, which comprisesa) simultaneously pumping one mole of crotonaldehyde or one mole of a compound which is converted under the reaction conditions into crotonaldehyde, about 5 to 30 moles of diethyl ketone and the aqueous solution or suspension of a strong base, through separate lines or at least partly in the form of a suitable mixture, continuously into a pressure vessel, which is heated where appropriate and which ensures vigorous mixing, in such a way thatb) the reaction temperature is between 150.degree. C. and 350.degree. C., and the average residence time in the pressure vessel is only about 0.1 second to 20 minutes.