SK278158B6 - Method of preparation of arenechromiumtricarboxylic complexes - Google Patents

Abstract

Arenechromiumtricarboxylic complexes are prepared by reaction of hexacarbonylchromium and aromatic compounds in presence of solvents reaction is realized by temperature 100 to 200 degrees of Celsius by catalysis of acids of bromsted type in mass 0,01 to 100 per cent weight volume, at which per cent weight volume is released on volume of saturated hydrocarbon.

Description

Technical field

The invention relates to a process for the preparation of arenclirometricarbonyl complexes.

BACKGROUND OF THE INVENTION

Arenotromotrocarbonyl complexes are prepared in various ways, mostly by reaction between the metal hexacarbonyl and the corresponding aroma. However, these reactions require long reaction times and rarely provide higher yields than 50%. The problems with these reactions are decomposition reactions occurring in the preparation itself, but also in the chromatographic isolation.

SUMMARY OF THE INVENTION

These drawbacks are solved by a process for the preparation of arenochromotrocarbonyl complexes by reaction of chromium hexacarbonyl and an aromatic compound in the presence of solvents according to the invention, characterized in that the reaction is carried out at a temperature of 100 to 200 ° C with catalysis of Bronsted type acids , where% vol. refer to the saturated hydrocarbon volume. The solvent and the volume of acid used are chosen so that the temperature of the reaction mixture is between 100 and 200'C. The reaction rate is increased with increasing boiling point of the reaction mixture.

The chromium hexacarbonyl is refluxed with the aroma in a particular solvent with the addition of Bronsted acid until the amount of carbon monoxide that corresponds to the complete reaction of the starting materials is released from the reaction mixture. However, it is a requirement of the acids that they do not react with the aromatic compound and do not decompose into undesired products during the reaction. Product isolation varies depending on the amount of acid and the kind of solvent used. If the solvent is non-polar and the amount of acid is in the range of 0.02 to 0.05 vol%, the product is allowed to crystallize in the reaction mixture at -18 ° C. The remaining reaction mixture is chromatographed after concentration. If more acid is used, it is first evaporated from the reaction mixture and the reaction mixture is then allowed to crystallize at -18 ° C and the remaining reaction mixture is chromatographed. When working in pure acid or lower boiling solvent, these can be evaporated directly on the evaporator. Using this method, quantitative yields can be achieved depending on the acid used. The lengths of the reaction times depend on both the acid used and the temperature of the reaction mixture. In specific cases, they are shortened to 1.5 to 5 hours.

seline and the reaction mixture is chromatographed. 1.0 g of acetophenone bromotriocarbonyl product (87%) was obtained. The composition and structure were confirmed by elemental analysis and NMR spectroscopy.

EXAMPLE 2 ml of toluene, 1 g of chromium hexacarbonyl in 70 ml of decahydronaphthalene and 0.3 ml of acetic acid are refluxed until the corresponding amount of carbon monoxide is released from the reaction mixture. Part of the product was isolated from the reaction mixture by crystallization (cooling to 18 ° C). The acid was then evaporated from the reaction mixture on a rotary evaporator and the reaction mixture was chromatographed. 0.6 g of the product toluene-chlorotri-carbonyl (57%) was obtained. The composition and structure were confirmed by elemental analysis and NMR spectroscopy.

Claims (1)

PATENT CLAIMS A process for the preparation of arenotromotrocarbonyl complexes by reaction of chromium hexacarbonyl and an aromatic compound in the presence of solvents, characterized in that the reaction is carried out at a temperature of 100 to 200 ° C with catalysis of Bronsted type acids in an amount of 0.01 to 100% by volume. . refer to the saturated hydrocarbon volume. End of document DETAILED DESCRIPTION OF THE INVENTION Example 1 1.6 g acetophenone and 1 g chromium hexacarbonyl in 70 ml decahydronaphthalene and 0.2 ml acetic acid are refluxed while monitoring the volume of carbon monoxide escaping. After the amount of gas that corresponds to the complete reaction of the starting materials (i.e. 305 ml) has escaped, the reaction is carried out. The reaction mixture was then evaporated on a rotary evaporator to remove the added acid.