SU141150A1 - Method for producing acid amides - Google Patents

Description

Methods are known for producing organic acid amides, for example, by reacting carboxylic acids with ammonia.

A disadvantage of the known methods is their complexity, especially with regard to the synthesis of halogen-substituted amides.

A method for producing fatty and aromatic fat amides is proposed, which consists in the interaction of an acid with cyanamide in an orthoxylene solution at 130-140 ° or in the absence of a solvent at 200 °. The output of amides 70-80% of theoretical. The reaction product is isolated by double recrystallization from chloroform and methanol.

In contrast to the known, the proposed method is simple; the reaction proceeds in one stage under easily accomplished conditions and allows obtaining amides of acids in a wide range of fatty and fatty aromatic series, including when interacting with halogen-substituted acids.

Example 1. In a four-necked flask equipped with a dropping funnel, a thermometer, a stirrer and a venting tube, 40 g of stearic acid are heated to 120-130 ° and 3 g of molten cyanamide is gradually added from the dropping funnel. Then the temperature is increased and the reaction is carried out at 190-210 ° until the release of CO2 is stopped. The mass that solidified after cooling is extracted with chloroform, the undissolved stearic acid amide crystallizes, and the amide is separated from the cyanuric acid. After the second crystallization from methanol, a pure product with m.p. 109-110 ° and yield 95-97% of theory, N7o 4.89.

Example 2. 0.243 mol (23 g) of chloroacetic acid and 35 ml of o-xylene are loaded into a three-neck flask, as described above. To the solution heated to 110 °, 0.110 mol (5 g) of molten cyanamide is added dropwise within half an hour. The temperature of the reaction mass is 141150-2, initially at first up to 120 ° and then up to 130 °. The reaction lasts 3 hours. During the reaction, a large amount of carbon dioxide is released and a small amount of hydrogen chloride. At the end of the reaction, the hot xylene solution is poured into a beaker. After cooling a heavy amide precipitate is formed from xylene. The precipitate is separated, washed with ether. Amide yield m.p. 120 ° (16.6 g) 75% of theory, N% 14.25.

Example 3. To the reaction flask was charged 0.244 mol (40 g) of trichloroacetic acid and 40 ml of o-xylene, to the solution heated to 90 ° was added dropwise 0.119 mol (5 g) of molten cyanamide. The reaction proceeds rapidly with the release of carbon dioxide and insignificant amounts of hydrogen chloride. The reaction temperature is 125-135 °. Duration of heating is 3 hours. The hot xylene solution is poured into a beaker, and a heavy precipitate of trichloroacetic acid amide precipitates from the cooled solution, which is separated and thoroughly washed with water. The output of the amide with so pl. 141 -142 ° (14.0 g) 72.5% of theory, N% 8.92.

By the same procedure, stearic acid amide was obtained with a yield of 95%.

Subject invention

A method for producing fatty and fatty-aromatic acid amides, characterized in that, in order to simplify the technology and use acids with reactive substituents as starting materials, the starting acid is heated with o-xylene with cyanamide to 150 ° C or less. no solvent — to a temperature of the order of 200 ° until gas evolution ceases, followed by recrystallization from chloroform and methanol.