DE2503313C3 - Process for the production of transtrans muconic acid - Google Patents

Description

'5

It is already known to produce trans-trans-muconic acid by bromination and dehydrobromination of adipic acid (Annalen 256 [1890] 1; Ingo Id, J. Chem. Soc. 119 [192!] 951; Farmer, J. Chem. Soc. 123 [1923] 2531 and Org. Synth. Vol. III [1955] 623). However, this synthesis is tedious and the yields are moderate, so that technical utilization is hardly an option.

It has now been found that leads to high yields of iran-trans-muconic acid, when Glyoxalacetale in the presence of a Lewis acid as a catalyst at -30 to + 6O ⁰ C, optionally in an inert solvent, is reacted with ketene and the resulting ß, j9'-Dialkoxyadipinsäuredialkylester hydrolyzed with alkali.

Suitable glyoxal acetals are those which differ from alcohols with 1 to 4, preferably 1 to 2 Derive carbon atoms. They are produced by known methods, for example in the case of Glyoxalmethylacetals by boiling glyoxal (80%) with an excess of methanol in for several hours Presence of acids as a catalyst. After removing the methanol, glyoxal methyl acetal can be added (Tetramethoxyethane) can be obtained in pure form by distillation.

The reaction of the glyoxal acetals with the diketene takes place in the presence of Lewis acids such as ZnCl ₂ and AlCl 3, preferably in the presence of BFj etherate. You can also work in the presence of an inert solvent such as diethyl ether, benzene or toluene. The reaction proceeds according to the following scheme:

RO OR O = C = CH ₂ + CH-CH CH ₅ = C = O

R.
O

RO

R.
O

OR

I® - (BF.,)

ROR
O

O = C-CH ₂ -CH-CH-CH ₂ -C = O

The alkyl β, jS'-dialkoxyadipate formed in this way is then cleaved by treatment with alkali, such as aqueous sodium hydroxide solution, to give trans-trans-muconic acid, which can be isolated from the reaction salt in the usual way by acidification and filtration.

Muconic acid and its derivatives are interesting compounds that can be polymerized into valuable products. Their esters can be reacted as a diene with .DELTA.1 -pyrrolidinocyclohexene to give the hexahydronaphthalene-1,4-dicarboxylic acid ester, which after dehydrogenation gives 1,4-naphthalenedicarboxylic acid ester. The latter compound is an important intermediate in the manufacture of optical brighteners.

example

At 0 ° C in 90 g (0.6 mol) of tetramethoxyethane (glyoxal methyl acetal), to which 16 ml of BF ₃ ether has been added, about 65 ml of ketene are introduced with dry nitrogen in about 2 to 3 hours, whereby for ensures good cooling and stirring. Stirring is continued for 1 hour at room temperature, diluted with ether and the ether phase is shaken twice with aqueous sodium chloride solution in which 30 g of KHCO _{3 has been} dissolved,

then out with pure saline. The ether phase

is dried with sodium sulfate, filtered, the ether removed and the crude reaction product at 0.4 Torr distilled.

Yield: 121 g (. 86.5 ° / od.Th)) 3, j9'-Dimethoxyadipinsäuredimethylester (bp = 108-109 ⁰ C at 0.4 torr; refractive index η = 1.4368) 23.5 g (0, 1 mol) | 3, j9'-dimethoxyadipic acid methyl ester are refluxed for 8 hours with a solution of 32 g NaOH in 50 ml water, cooled, suction filtered, dissolved in water, precipitated with concentrated hydrochloric acid at pH 1, washed neutral with water and dried . 2.2 g (86% yield) of trans-trans-muconic acid with a melting point of 298 to 300 ^° C. are obtained.

Claims (1)

Claim: Process for the preparation of trans-trans-muconic acid, characterized in that a glyoxal acetal is ^{reacted with ketene in the presence of a Lewis acid as a catalyst at -30 to + 6O 0} C, optionally in an inert solvent, and the β, j3 'formed -Diaikoxyadipic acid dialkyl ester hydrolyzed with alkali. IO