DE860200C - Process for the production of oily esters - Google Patents

Description

Process for the preparation of oily esters It is known that by esterification of alcohols with di- and polycarboxylic acids oily compounds obtained, which can find many uses in technology; z. B. as a plasticizer for paints or plastics, as lubricants, as pressure oils for presses: and brakes as well as in, the leather and textile industry. You already have for the esterification Alcohol mixtures proposed by: reduction, the. During the oxidation of higher molecular weight obtained from non-aromatic hydrocarbons. Camboxylic acids are obtained, with with particular advantage are the low-boiling constituents, which have a maximum of 1 a carbon atoms contained in their chain, the so-called precursor acids, can be used. Multiple But the esterification products obtained in this way make their volatility detrimentally noticeable due to the presence of. Alko-`fetch. with very low Molecular weight, di. H. with less than 7 carbon tons. One can. Although these proportions from the fatty acids before the reduction, or from the Alcohols. remove by distillation after reduction .; but one must lamb find some other use for them.

It was. it has now been found that these low-molecular-weight acid components can also be found that by oxidation of higher molecular weight non-aromatic hydrocarbons get mixtures of carboxylic acids with more than 3 carbon atoms in the molecule for the production Not very volatile and therefore also usable in the warmth of fermentation products can take advantage of dividing the niche into two fractions. of which .the one acids with no more than 7 carbons, the other the hersiadiende Contains acids; the first fraction ketonized in a known manner, the obtained Ketone mixtures reduced to the corresponding mixtures of secondary alcohols and these as well as the higher molecular weight primary alcohols produced by direct reduction the second fraction, d. H. the acids freed from the low-boiling components are obtained, esterified jointly or in succession with the dicarboxylic acids. Where the first fraction must be cut off, depends on the intended use of the ester and the molecular size of the D: i or polycarbo: acid acids used for the esterification, which naturally also has an influence on the volatility of the esters. It is sufficient in general, the acids with fewer than six or even up to seven carbon atoms to distill off and to ketonize and then to secondary the ketomes obtained in this way Hydrogenate alcohols.

The, ketonization takes place in a known manner, for. B. by distillation, the alkaline earth salts, more appropriate catalytically. Passing the vapors of the acids over catalysts, such as manganese oxides or cerium carbonate, at temperatures between about 350 and 50 °. The reduction of the ketones and the non-ketonized higher acids is carried out in a known manner either catalytically with hydrogen under pressure in the absence of hydrogenation catalysts, such as copper, nickel, cobalt or copper-chromium oxide, etc., at elevated temperature, or by treating the Ketones and, the higher acids, which have previously been esterified with low molecular weight alcohols, carried out with alkali metals in alcoholic solution.

For the escalation of the so. obtained primary and secondary. Alcohols can contain all kinds of polycarboxylic acids, such as oxalic acid, succinic acid, adipic acid, methyladipic acid, sebacic acid, phthalic acid, Methane tetracarboxylic acid, Buüantetracarboxylic acid, thiodibutyric acid or dipropyl ether dicarboxylic acid or their anhydrides or halides can be used. - You can also use mixtures use different di- and polycaxboxylic acids.

It is particularly expedient, not mild part esterify to Verestemng the mixtures of primary and secondary alcohols to use- but first the secondary alcohols with excess polycarboxylic under iell and admit to this until dve primary alcohols; the esterification, if necessary under more energetic conditions, e.g. B. leads to an end at elevated temperature or after the addition of catalysts. The known esterification catalysts, such as zinc dust, magnesium, bleaching earth, active charcoal, and also sulfuric acid, hydrochloric acid or benzenesulfonic acid, are suitable as catalysts. It is also often advisable to esterify in the presence of volatile, inert organic solvents, such as gasoline, Be = ol, Totuene, carbon tetrachloride or methylene chloride, the water of reaction being removed azeotropically from the distillate. After the esterification has taken place, the reaction mixture is washed neutral with a dilute alkali solution, the solvent is driven off and the ester is treated in the usual manner: with steam, drying, bleaching, filtering, etc. cleaned. Light-colored, almost odorless oils are obtained which are eminently suitable for the purposes mentioned at the outset.

Air's starting materials for this proceeding come first Line the so-called first run fatty acids into consideration, but you can, also mixtures process that contain high molecular weight acids, e.g.: those with up to 1q. or 16 or more carbon atoms ..

It is known to use esters of podycarboxylic acids with alcohol mixtures, as they are in the oxidation of higher molecular weight paraffin hydrogensn or : can be obtained by reducing mixtures of fatty acids, @produce. Such Mixed alcohols, however, also produce low molecular weight: alcoholic alcohols, their esters for many Purposes too volatile sinidi. In addition, the direct reduction is more discrete Fatty acids technically much more difficult to perform than ketonization and subsequent ones Hydrogenation, so that the mcbrs-stage treatment used according to the invention is technical voirteilbafter is known as the way of working. In addition, the present provides Process .Ester, which is not only characterized by low volatility, also segregate through distinguish deep solidification points, while one in the Veresterriunig of primary Alcohol mixtures obtained by direct reduction of fatty acids., .Ester with a significantly higher freezing point is obtained.

The parts given in the following examples are parts by weight. -Example i ioö parts included: Vorlauffatty acid mixture with q. to 10 carbon atoms from oxidized paraffin slack from carbohydrate hydrogenation are distilled. the to igo ° 'overhanging proportions (about 4: 2' / 0, acid number 56o, essentially the Acids C4 and C, containing) are at q.oö ° in. Vapor form over a Mamganoxidulkatalysator where they are converted into ketones. These are at 180 '°' and Zoo at hydrogen pressure in the stirred autoclave in the presence of a copper caialyser hydrogenated until no more hydrogen is absorbed. You get 27 parts of one Mixture of secondary alcohols of chain length C7 to C9.

The residue remaining from the distillation described above (Acid number 391) is added with the addition of a copper-r-chromium catalyst at zq.o ° and zoo at reduced with hydrogen to a mixture of alcohols C to Ca. You get thereof 50 parts. 44 parts of plithalic anhydriide are now used with the 27 parts: secondary alcohols stirred for 2 hours at 125.00. Be on it after adding, i part of concentrated sulfuric acid, the 50 parts of this mixture of the primary alcohols slowly entered and the temperature increased to 150 °, whereby the water of reaction is removed while passing nitrogen through. After about 3 The esterification is finished hours. The esterification mixture is diluted with Sodalösturg washed neutral, dried and bleached with silica gel. You get i io parts of a yellowish oil which is an excellent plasticizer, e.g. B. for nitro lacquers and polyvinyldhloTildfo @ lien.

Examples A fatty acid mixture of oxidized hard paraffin with approx 3 to: -i2 carbon atoms is distilled into two approximately equal parts disassembled. The first faction. contains the acids from about C3 to C7, the second the from, about C, to C12.

100 parts of the first fraction are, as described in Example i, converted into ketones. These will. together with 100 parts of acids of the second fraction, which have previously been esterified with ethanol, after addition of absolute ethanol, treated with metallic sodium with vigorous stirring until the reduction binds. After acidification, washing out, this ethanol with water and: drying; 73 parts of adpsic acid are added to the alcohol mixture, about 15 parts, and, after the addition, 60 parts of methylene chloride and 1 part of succinic sulfomic acid are refluxed with stirring until 18 parts of water have distilled over. After the usual cleaning, an oil with a pour point of -5o0 is obtained, which is ideally suited as a lubricant.

Claims (2)

PATENT CLAIMS: i. Process for making oily esters, thereby characterized that one .by oxidizing higher molecular weight non-aromatic hydrocarbons Mixtures of carboxylic acids obtained with more than 3 carbon atoms in the molecule broken down into two fractions, one of which is acids with no longer all 7 carbon atoms, If others contain the higher-boiling acids, the first fraction in itself, got, the way converted into ketones and this and the second fraction as well in itself; in a known manner to the corresponding secondary; or primary; Alcohols; reduced, which, one & nn mean, or one after the other with multiple, Carboxylic acids according to known ones. Mefodei, esterified. 2. The method according to claim i, laduToh ge. know @ that @ that the polybasic carboxylic acids initially partially with the secondary, däxen: alcohols and then esterified with the primary alcohols.