SU455939A1 - The method of obtaining the monoamine salts of fumaric or maleic acid - Google Patents

Description

one

The invention relates to a process for the preparation of monoamine salts of unsaturated dicarboxylic acids, which can be used as starting materials for the synthesis of mixed salts of these acids, used as hardeners for aminoplasts.

A known method for producing monoammonium and monoamine salts of fumaric and maleic acids by the interaction of equimolar amounts of these acids with ammonia or an appropriate amine.

However, such a reaction is accompanied by side processes: the formation of a medium salt or the addition of an amine through the double bond of these acids, which reduces the yield of the target product to 25-30%. Insufficient yields of the target product limit the application of the known method.

In order to increase the yield of the target product according to the proposed method, the fumaric or maleic acid is reacted with the corresponding p-aminocrotonic esters with the subsequent isolation of the formed salts by known methods.

The method is based on the reaction of the interaction of these acids with p-aminocroton esters, which allows obtaining acidic salts with primary amines and ammonia with yields of 61.8-93.3%.

CHS-S: CH-SOOS, H + HOOC-CH-CHRNH-COOH-CH CH-CH-SOOS, H,

N: 0

I RN + OOCCH.CHCOOH L

 UNSPNSIFC + R

+ CHjCOCHsCOOC.H ,,

where R H or alkyl.

The reaction with maleic acid is carried out in the medium of ether at a temperature of 25-30 ° C, with fumaric acid - without solvent when heated in a water bath. The method is simple in execution, the original products are readily available. The aceto acetic ester which is separated in the reaction can be reused to prepare p-aminocroton esters. Example 1. The monoammonium salt of maleic acid is obtained by curing 1.16 g (0.01 mol) of maleic acid and 1.29 g (0.01 mol) of the p-amino-roto ester in 10 ml of ether at 20-30 ° C for three days The resulting salt is triturated with ether, filtered and washed with ether. Output 0.9 g (61.8%), so pl. 173 ° C (absolute alcohol - dry ether).

Found,%: C 36.39; H 5.31; N 10.58.

C4H7NO4.

Calculated,%: C 36.09; H 5.30; N 10.51.

Example 2. Monomethylammonium salt of maleic acid is obtained from maleic acid and pN-methylaminocroton ester with a yield of 67%, so pl. 125 ° C (absolute alcohol - dry ether).

Found,%: C 40.74; H 6.19; N 9.63;

SbN9Y04.

Calculated,%: C 40.82; H 6.16; N 9.51.

Example 3. The monoammonium salt of fumaBary acid is obtained by heating in a water bath for 18–20 hours equimolecular amounts of p-amnokroton ester and fumaric acid. The reaction mixture is transferred to a beaker, after 2 days the resulting salt is triturated with ether, filtered and non-recrystallized from alcohol. The output of 93.3%, so pl. 232-233 ° C (absolute alcohol).

Found,%: C 36.00; H 5,491; N 10.54.

C4H7NO4.

Calculated,%: C 36.09; H 5.30; N 10.51.

Example 4. Fumaric acid monomethylammonium salt is obtained by heating equimolecular amounts of pN-methylaminocroton ester and fumaric acid in a water bath for 25 hours. The output of 62.3%, so pl. 177-178 ° C (absolute alcohol)

Found,%: C 40.74; H 6.19; N 9.62.

C5H9NO4.

Calculated,%: C 40.82; H 6.16; N 9.51.

Subject invention

Claims (3)

1. A method of obtaining monoamine salts of fumaric or maleic acids from the corresponding acids, characterized in that, in order to increase the yield of the target product, the original acids are reacted with the corresponding p-aminocroton esters, followed by isolation of the resulting salts by known methods. 2. A method according to claim 1, characterized in that the reaction of the corresponding ester with maleic acid is carried out in a medium of sulfuric ester at a temperature of 25-30 ° C. 3. A method according to claim 1, characterized in that the reaction of the corresponding ester with fumaric acid is carried out by heating in a water bath.