DE2448339A1 - PROCESS FOR THE MANUFACTURING OF UNSATATULATED CARBONIC ACID ESTERS - Google Patents

Description

BASF Aktiengesellschaft

Our reference: O.Z. 50 885 mu / ri 67OO Ludwigshafen, October 8, 1974

Process for the preparation of olefinically unsaturated carboxylic acid esters ;

The invention relates to a process for the production of f, cT-unsaturations (X-hydroxycarboxylic acid esters of the general formula

R ^ CHsCH-CH-CH-COOR ³ (A)

t t

R ² OH

1 2

wherein R and / or R is a hydrogen atom or identical or different - optionally bearing indifferent substituents alkyl radicals with, for example, 1 to 20 carbon atoms or aryl radicals with, for example 6 to 20 carbon atoms and R is an - optionally bearing chemically indifferent substituents - alkyl radical with, for example, 1 to
atom.

Mean 1 to 20 carbon atoms. R is preferably a hydrogen

The invention consists in the knowledge that carboxylic acid esters of the aforementioned general formula are readily obtained, if you have an olefin of the general formula

R ^ CH = CH-CH ₂ R ² (B)

1 2

in which R and R have the aforementioned meaning, with a Glyoxylic acid esters of the general formula

OCH-COOR ³ (C)

or its hemiacetal

ROCH (OH) -COOR ³ (D)

wherein R ^{3 has} the aforementioned meaning and R denotes the remainder of a short-chain aliphatic alcohol.

- 2 6 0 9 8 17/1167

- 2 - O.Z. 30 885

In other words: The invention is based on the knowledge that the chemical reaction equation

(B) + (D)} (A) + RAW

can be realized as a chemical process.

The condensation of olefins with aldehydes is known per se ("Prins reaction") and is carried out in a strongly acidic environment. The transfer to εν-oxocarboxylic acids is known from work by Savostianoff (CR. 263 »605 (^ S) ) and from German Offenlegungsschrift 2 103 686. In both cases, however, cyclic «-hydroxy-X'-lactones are obtained. It is therefore surprising that with esters or hemiacetal esters of glyoxylic acid a condensation succeeds in a neutral environment and completely different compounds are obtained in good yield.

To implement the implementation, it is sufficient to mix the starting materials on the left in the above reaction equations and to heat if necessary; a catalyst for carrying out the reaction or a solvent is generally not required. Working in a basic or acidic environment, i.e. using a basic or acidic catalyst, can be done in in some cases lead to side reactions.

As the reaction temperature, a range C turns of, for example 50 to 25O ⁰ as appropriate; If one or both of the starting materials is volatile, it may be necessary to work under - generally moderate overpressure in order to achieve a sufficient reaction rate. In this case, for example, pressures between 1 and 50 bar are suitable, but the fundamental feasibility of the reaction is not restricted to the specified temperature and pressure ranges.

The olefins used are technically and economically extensive developed raw materials.

6 0 9817/1167

1 4 4 c -3 3 α

- 3 - O.Z. 50 8δ5

The process is preferably applied to the 1-olefins; for example are propene, pentene-1, hexene-1, dodecene-1 and the im Experiment shown olefins are very suitable starting materials. the Olefins can also be branched in the alkyl radical and optionally have chemically indifferent substituents, e.g. ether groups or halogens, provided that they are arranged sufficiently far away from the reactive site.

Glyoxylic acid is also a commercially available product, obtained e.g. in the oxidative dehydrogenation of glycol. The esterification with alcohols gives the hemiacetal esters. The dehydration of the technically easily accessible glycolic acid esters leads directly to glyoxylic acid esters, which in turn are subjected to conversion to hemiacetals in a known manner can be.

The unsaturated produced from these two product groups Hydroxycarboxylic acid esters are versatile intermediates. By amination and / or hydrogenation, e.g. ^ .- aminocarboxylic acids or 1,2-alkanediols obtained. The one from Butene-1 2-hydroxyhexene-4-carboxylic acid esters obtainable and glyoxalic acid esters is converted into sorbic acid, which is important for food preservation, by splitting off water.

example 1

5OO g of hydroxy-ethoxy-acetic acid ethyl ester (3, ^ g-mol) are placed in a 3 l autoclave, 500 g of 1-butene (9 g-mol) are injected and then ^{kept at 200 °} C. for 8 hours. The reaction result after cooling and letting down are 620 g of a red-brown, clear liquid. By distillation in a 30 cm long packed column, 266 g of colorless 2-hydroxyhexene-4-carboxylic acid ethyl ester (Sp. 72-78 ° / 8 mbar) are obtained therefrom. The boiling point at normal pressure or kO mbar is determined to be 197 ° or 104 °. The purity of the substance, determined by gas chromatography, is better than 98 %. Composition, double bond bromometrically according to Kaufmann or Byrne and Johnson, saponification number and hydroxyl number agree with the specified structure.

609817/116 7

ORIGINAL INSPECTED

O.Z. 30 885

Example 2

a) 500 g of hydroxy-ethoxy-acetic acid-ethyl ester (3.4 g-mol) and 750 g of octene-1 (6.7 g-mol) are kept in a 3 liter autoclave at 200 ^° C. for 5 hours of the system is 11 bar. As reaction product after cooling and venting to 1240 g clear almost colorless liquid ₉ is obtained. The distillation on a 30 cm long packed column first separates ethanol and octene. At 135 to 136 ⁰ (13 mbar) 493 g of a gas-chromatographically pure fraction are then obtained. The substance is identified as ethyl 2-hydroxy-dec-4-ene-carboxylate using the usual means (double bond equivalent, hydroxyl number, ester steel).

b) The ester prepared according to a) is hydrogenated ^{at a hydrogen pressure of 250 atmospheres and 200 °} C. on a heavy metal contact. The product in question no longer contains any ester components. It boils at 165 - 168 ° C / E _S 7 mbar _{0 The} composition and properties correspond to those of 1,2-decanediol.

- 5 0 9 8 1 7/1187

ORIGINAL INSPECTED

Claims (1)

- 5 - O.Z. 30th Claim Process for the preparation of olefinically unsaturated carboxylic acid esters the general formula R ^3- -CH = CH-CH-CH-COOr ³ (A) R ² OH 1 2 wherein R and / or R is a hydrogen atom or identical or different - optionally bearing indifferent substituents - alkyl radicals having, for example, 1 to 20 carbon atoms or aryl radicals having, for example, 6 to 20 carbon atoms and R ^{5 is} an - optionally bearing chemically indifferent substituents - alkyl radical having, for example, 1 to 20 C atoms mean, characterized in that one is an olefin of the general formula R ^ CK = CH-CH ₂ R ² (B) 1 2
in which R and R have the aforementioned meaning, with a glyoxylic acid ester of the general formula OCH-COOR ³ (C) or its hemiacetal ROCH (OH) -COOR ³ (D) where R has the aforementioned meaning and R is the remainder of a short-chain aliphatic alcohol means converts. BASF Aktiengesellschaft, 60981 7/1167