DE863196C - Process for the production of higher molecular carboxylic acid esters - Google Patents

Description

Process for the preparation of higher molecular weight carboxylic acid esters. It is known to use aldehydes, e.g. B. acetaldehyde, higher aliphatic aldehydes, benzaldehyde or aldehydes of the hydroaroromatic series, by a, action of aluminum alcoholate, optionally in the presence of activators, eg. B. copper, zinc, iron, nickel, manganese, cadmium, etc. or halides of mercury, zinc, tin, aluminum or silicon, to be converted into carboxylic acid esters with double the carbon number. The yield of Carbonsätircestern with twice the carbon number is when using low molecular weight aldehydes, z. B. of acetaldehyde, propionic or butyraldehyde, is satisfactory, but it decreases with increasing carbon number of the aldehyde. It has now been found that particularly good yields of higher molecular weight esters are obtained if the starting materials used are the products consisting mainly of aldehydes, which are obtainable by the action of carbon monoxide and hydrogen on olefinic hydrocarbons having at least 5 carbon atoms, and the aluminum compounds of alcohols are used as catalysts Carbon count roughly corresponds to that of the aldehydes to be converted, used.

The. Reaction is effected in a liquid medium. She provides warmth, and it is advisable to keep the temperature from increasing by cooling high, e.g. B. over 40 ', appropriate not 'over 2ö' rises. The best, Yields are obtained in the range from 0 to 15 ". It can be used in the presence of inert diluents work, but 4-st it is expedient to exclude the presence of water, as it is known to decompose alcoholates.

* iier '- advantage of the present process compared to the use of metal, metal ethylate or butyl alcoholate, in particular aluminum ethylate, which has hitherto been used almost exclusively as a catalyst, consists in a very substantial improvement in the yield. The esters obtained according to the invention can be used in the wax industry.

The parts given in the examples below are parts by weight. Example i The catalyst is prepared in a manner known per se in the following manner. 27 parts of atomized aluminum powder with addition of o, 5 parts Ou, ecl <: silver chloride with 57o part of an in Wesent-Fichen from alcohols of 12 - existing carbon atoms alcohol mixture which is obtained by hydrogenating a by addition of Kehlenoxyd and hydrogen to a Krackolefin (Kp. = 170 won products to igo ') available, heated with stirring to i 2obis 1 5 oo. 4 minutes after the formation of alcoholate began, about% of the expected amount of hydrogen was evolved. The alcoholate formation has ended after 15 minutes.

To this catalyst is allowed under stirring at et 'wa io' 8OOO parts of a 8o "/ o, Aldehydgenlisches how to use it for the preparation of the bound-en in the catalyst alcohol mixture to flow to give carefully maintains the temperature by cooling. When all Aldehyde has been added. Stirring is continued for 3 hours without cooling.

The alcoholate used as a catalyst is now diluted by adding it Hydrochloric acid destroyed, the aqueous aluminum chloride solution formed separated and the nidlitwäßrig ## layer is distilled under reduced pressure. You get so 540o parts of an ester mixture of (bp "= .23o to 240 '), its mean chain length C, is 4. Example 2 One obtained by cracking a hydrocarbon oil Product containing gol / o olefins (mean carbon number C, 1) is known in Way at 140 'and a pressure of 22o at in the presence of a cobalt-containing catalyst with a mixture. equal parts of the volume of carbon dioxide and hydrogen are treated. That Reaction product -has a carbonyl number of 186 (determined by reaction with hydroxylathinchloehydrate), entc # p, r, ec # hen, d 6io parts of monomeric aldehydes in 100% of the product.

If this product is treated in the manner described in Example i with the aluminum alcoholate mixture of alcohols with an average chain length of C12 as a catalyst, one obtains 50 parts of an ester mixture with an average chain length of C24, which is 200 parts more than Based on the determined carbonyl number were to be expected, from which one must conclude that p (> polymeric amehydes are also present in the starting material, which are also converted.

Claims (1)

PATENT CLAIM: Process for the production of higher molecular weight. Carboxylic acid residue -, - rn by treating aldehydes having at least 6 carbon atoms with a metal alcoholate in the absence of water and at low temperature, characterized in that the starting materials obtained by the action of carbon oxide and hydrogen. olefinic hydrocarbons with at least 5 carbon atoms, which are obtained mainly from aldehydes, and are used as catalysts in the aluminum compounds of alcohols, the carbon number of which corresponds approximately to that of the aldehydes to be converted.