Basf Aktiengesellschaft

Badische Anilin- & Soda-Fabrik Aktiengesellschaft

Lothar Arnold

Gerd Kaibel

Werner Hoffmann

Manfred Stroezel

Franz J Broecker

Axel Nissen

Hans Kiefer

Lothar Janitschke

Harald Laas

Walter Rebafka

Paul Grafen

Otto Hertel

Peter Tavs

Otto Woerz

Hans-Juergen Scheiper

Heinrich Pasedach

Manfred Braun

Horst Schauer

Horst Pommer

Palladium catalysts can be obtained by vapor depositing metallic palladium on a carrier, treating the palladium coating with a metallic inhibitor by vapor deposition, and heating the product at from 300.degree. to 800.degree. C., and can be used for the partial hydrogenation of triple bonds to olefinic double bonds.

Palladium catalyst

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

Increasing the yield of 2.5.6-trimethylcyclohex-2-en-1-one

Ionones are prepared by cyclization of pseudoionone with concentrated sulfuric acid in the presence of an organic solvent or diluent, while cooling, and by dilution of the reaction mixture with water, by a continuous process in which the pseudoionone is combined with an aliphatic or cycloaliphatic hydrocarbon which boils at 25.degree.-65.degree. C. under the reaction conditions, or an aliphatic chlorohydrocarbon, and the sulfuric acid, with thorough mixing and evaporative cooling by partial or complete vaporization of the solvent present in the reaction mixture, combination being effected so that the temperature of the reaction mixture is from 25.degree. to 65.degree. C. and the residence time of this mixture before it is diluted with water is from 0.5 to 20, preferably from 0.1 to 5, seconds. The novel process can be used to prepare .alpha.- and .beta.-ionone in a technically simple and advantageous manner and in very good yields.

Preparation of ionones

An improved process for the preparation of unsaturated ketones of the general formula I ##STR1## where R.sup.1 is --CH.sub.3, ##STR2## and R.sup.2 and R.sup.3 are different and each is H or --CH.sub.3, by reacting an aldehyde of the general formula II ##STR3## with a molar excess of acetone or methyl ethyl ketone at an elevated temperature in the presence of an aqueous alkali metal hydroxide solution, wherein (a) all the reactants are mixed thoroughly, (b) the temperature is kept at from 10 to 120.degree. C. above the boiling point of the lowest-boiling component and (c) the pressure is kept at from p to 100 bar, where p is the vapor pressure of the mixture at the reaction temperature. The products methylpseudoionone, dimethylpseudoionone, pseudoirone, methylpseudoirone and dimethylpseudoirone are useful scents and scent intermediates. In addition, pseudoionone is an important intermediate for the industrial preparation of vitamin A, and 6-methyl-hepta-3,5-dien-2-one is a sought-after aromatic.

Preparation of polyunsaturated ketones

An improved process for the preparation of higher unsaturated ketones, such as geranylacetone and farnesylacetone, by reacting a .beta.,.gamma.-unsaturated alcohol and an alkyl acetoacetate at an elevated temperature in the presence of an organic aluminum compound, with elimination, and removal, of the alcohol derived from the alkyl acetoacetate in a reactor system carrying a fractionating column. The improvement in the purity, yield, and especially space-time yield of the product is achieved by starting from an alcohol having a higher boiling point than that of the alkyl acetoacetate used, carrying out the reaction in the presence of a small amount of an inert liquid which has a boiling point between that of the alkyl acetoacetate and the alcohol to be eliminated therefrom, and ensuring that the temperature at the bottom of the fractionating column is only slightly higher than the boiling point of the added liquid, under the prevailing pressure.

Preparation of higher unsaturated ketones

A process for the production of 2,3,6-trimethylphenol in which diethyl ketone is reacted in the presence of a basic reagent with crotonaldehyde or methyl vinyl ketone (or a compound which in the presence of a basic reagent is converted into crotonaldehyde or methyl vinyl ketone) and the 2,5,6-trimethyl-2-cyclohexen-1-one or 2,3,6-trimethyl-2-cyclohexen-1-one formed is dehydrogenated.

Production of 2,3,6-trimethylphenol

Growing community of inventors

Heidelberg, Germany

Lothar Arnold