SU477997A1 - The method of obtaining-alkene acids or their esters - Google Patents

Description

(54) METHOD FOR PRODUCING CO-ALKAL ACIDS

OR THEIR ETHERS

The proposed method further comprises the step of hydrolysis of the esters formed, which is carried out by a known method. The output of CO alkeneo acids by this method to 75%. The end position of the double bond in the target product. confirmed by IR and NMR spectra.

The dehydrocarboxylation of monoesters can be carried out by adding a tetravalent lead carboxylate solution previously prepared from tetraanejpaTa lead and an approximately equicular amount of the decarboxylated monoester into the reaction zone of the benzene solution of the carboxylate.

Example 1; (for comparison). To a mixture heated to 80 ° C, 13.7 g (0, O5 mol) monomethyl azelainate, 1 g (0.005 mol) Cy, (OAc), 0.4 ml (0.05 mol of pyridine and 1 OST ml of benzene in an inert gas atmosphere (nitrogen or argon) is gradually poured (2 hours) with vigorous stirring of the mixture 23.5 g (0.05 mol) of lead tetraacetate. The mixture is additionally heated for another 1 hour, cooled, the benzene solution is separated from the precipitate, the precipitate is extracted with ether the solution and the ether extract are washed with dilute hydrochloric acid and water and then distillation gives 4.8 g (46%) of 60-octyl methyl ester oic acid, mp. bales. 65-67 ° C / 7 mm Hg. v .;

tt 1.4324.

3 g of methyl-CO-octenoate, 3 g of food potassium and 15 ml of water are boiled for 2 hours, cooled

give, neutralized with hydrochloric acid,

extracted with ether and 2.5 g (91%) of CO-octhenoic acid, t.p., 105-110 ° C / 10 mm-pt from the extract by distillation. Art.

Methyl- and ethyl-CO-pentenoate and methyl-CO-nonenoate were also prepared by the same procedure (see table).

Monoethyladipate

50 50

Monoethylapat5O 2-3.6

Monom etiladipat 25 10

Monom etilazelainat 50 50

22 10

15

50 50

Monomyl sebacate 75 30

 calculated on. injected TAS, outside the parentheses, found by gas-liquid chromatography, in parentheses, considering the product preparatively separated by distillation. A - for example 1, B - for example 2.

85 (74) 85-87 / 20

Also

50A Methylnonenoate, - (50) 97-103 / 10

83 (74) 90-95 / 10

B Same

Example 2. To a heated C, remove 6.5 g (0, OZ mol) of monomethyl sebacacate, O, 6 g (0.003 mol) of CuCOAc), 2.4 g (O, OZ mol) of pyridine and

75 ml of benzene in an atmosphere of inert ha gradually added (3-4 hours) with stirring, a previously prepared solution of 13.3 g (0.03 mol) of TAS and 9.7 g (0.05 mol) of monomethyl sebacate in 15O ml of benzene. The mixture is additionally heated for an additional 1 hour and then treated, K (ak is described in Example 1. Obtain 3.1 g (75%) of CO -nonenoic acid methyl ester, bale 90-95 C / 15/10 mm Hg. Art. The yield of methyl-CO -nonenoate, determined by gas-liquid chromatography in benzene-ether solution. Before distillation, “xi 83%.

The IR and NMR spectra of the obtained ether are identical with the corresponding spectra of methyl W-octenoate (see Example 1). 25

The methyl esters of vinyl acetic, allyl acetic, and 05 -octhenoic acids were also prepared by a similar procedure (see table).

Subject invention

Claims (2)

1. A method for the production of CO alkeneic acids or their effluents by decarboxylation of alkane dicarboxylic acid monoalkyl ester under the action of carboxyl lead in the presence of a copper salt and pyridine at 50-8 ° C, followed by isolation of the resulting ester or its conversion into acid by known methods, characterized in In order to increase the yield of the target products, the lead carboxylate is used in the form of a solution and the normal alkane dicarboxylic acid monoester is used as the starting monoalkyl ester. 2. The method according to claim 1, of which is that the monoester of a normal alkanedicarboxylic acid and lead carboxylate are taken in a ratio of 2-2.5: 1.