CN104725239A - Preparation method of high fatty amine - Google Patents

Abstract

The invention discloses a method for preparing higher fatty amines, which belongs to the technical field of organic compound synthesis. The present invention uses the solution of α-halogenated fatty acid and lower amine to carry out aminolysis reaction in normal pressure or autoclave reaction kettle, and firstly prepares alkyl amino fatty acid; after removing unreacted lower amine, the product is dissolved in ethanol and then It is placed in an autoclave reaction kettle, decarboxylation reaction is carried out at 200-300°C, and high-purity high-grade fatty amine is obtained through further purification. This method can directly use natural fatty acids as raw materials, does not require expensive catalysts and complicated synthesis processes, and the preparation process is simple, economical and environmentally friendly. It needs to be reacted under the conditions of high temperature, high pressure and metal catalyst, the reaction conditions are harsh, the risk is high, the energy consumption is large, and the cost is high.

Description

A kind of preparation method of higher fatty amine

technical field

The invention relates to a method for synthesizing high-level aliphatic amines by using α-halogenated fatty acids as raw materials, performing aminolysis reaction with low-level amines, and then decarboxylation reaction, which belongs to the technical field of organic compound synthesis.

Background technique

Higher fatty amines usually refer to fatty primary amines, fatty secondary amines and fatty tertiary amines with more than 8 carbon atoms. They are important organic intermediates and are widely used in petrochemical, pharmaceutical, agricultural chemical and surfactant manufacturing. and other industries. At present, there are mainly three kinds of relatively mature fatty amine production processes in industry: one is to use fatty alcohol as raw material, and under the action of metal catalyst, directly react with lower amine in one step to obtain primary or secondary amine; the second method is sufficient to Natural fatty acids are ammoniated under high temperature and high pressure catalytic conditions to prepare fatty nitriles, and then undergo hydrogenation reduction to obtain fatty amines. This method is often used in foreign industries; the third process uses aliphatic aldehydes and ketones as raw materials. , followed by catalytic hydrogenation and reduction to amines under high temperature and pressure conditions. The above three processes all need to be reacted under high temperature, high pressure and metal catalyst conditions. The reaction conditions are harsh, the requirements for reaction equipment are high, the risk is high, the energy consumption is large, and the cost is high, which leads to the high price of fatty amines, which limits the use of fatty amines as Development and application of raw materials for fine chemical products.

Contents of the invention

The purpose of the present invention is to provide a method for preparing high-level aliphatic amines from α-halogenated fatty acids and low-level amines through a two-step simple reaction, so as to improve the shortcomings of the current synthesis of fatty amines that require expensive catalysts and harsh conditions of high temperature and high pressure . The technical solution provided by the invention can greatly reduce the production cost of the high-grade fatty amine, simplify the process flow, and improve the current situation that the high-grade fatty amine is expensive.

The object of the present invention can be achieved through the following technical scheme: α-halogenated fatty acid and excess lower amine are carried out amination reaction in normal pressure reactor or autoclave reaction kettle, add high temperature autoclave reaction kettle after removing unreacted lower amine , react at 200-300°C for 3-6 hours. After the reaction is completed, high-purity higher aliphatic amines are obtained after further purification. The synthetic route is as follows:

In the reaction formula, R ₁ is a C ₈ ~C ₃₈ saturated linear or branched, single-carbon or mixed-carbon hydrocarbon group; that is, the general formula is C _n H _2n+1 , where n=0~38; X is C1, Br or I; R ₂ and R ₃ are saturated linear or branched hydrocarbon groups, that is, the general formula is C _n H _2n+1 , where n=0, 1, 2 or 3.

The specific synthesis process is as follows:

Using ethanol or water as a solvent, put α-halogenated fatty acid and lower amine in a molar ratio of 1:3~10 into a normal pressure reactor or an autoclave reactor, stir at a constant temperature of 60~120°C for 3~14 hours, and remove After removing the unreacted lower amine and solvent, put it into a high-temperature autoclaved reaction kettle, and react at 200-300°C for 3-6 hours. After the reaction is completed, the solvent is distilled off under reduced pressure and dried, then acidified by adding hydrochloric acid, extracted and separated by petroleum ether (30-60°C) to obtain fatty amine hydrochloride, neutralized by adding NaOH to pH = 7, anhydrous diethyl ether Purified higher aliphatic amines are obtained by extraction.

Beneficial effects of the present invention:

(1) The present invention uses α-halogenated fatty acids as raw materials, reacts with lower amines, and then synthesizes higher aliphatic amines through decarboxylation. Compared with the usual expensive catalytic process and high temperature and high pressure process, the production cost of advanced aliphatic amine can be greatly reduced, the reaction conditions are mild, and the process flow is simple.

(2) The present invention can obtain higher aliphatic amines with odd number of carbon atoms by a simple method.

Detailed ways

The synthesis of embodiment 1 nonylamine

Add 0.10 mol of α-bromodecanoic acid and 0.30 mol of ammonia (28% aqueous solution) into the autoclave, quickly seal it, stir to make it evenly mixed, and then react at constant temperature at 60° C. for 3 hours. After the reaction, use NaOH alcohol solution to adjust the ammonolysis reaction crude product to alkaline, and remove excess ammonia and water by rotary evaporation; dissolve the dried product in ethanol and add it to a closed high-temperature reactor, and react at 200°C for 3 hours. After the reaction is completed, the solvent ethanol in the product is removed by rotary evaporation and dried. Add hydrochloric acid to make the system pH<2; add petroleum ether (30-60°C) to extract and separate the fatty acid to obtain an aqueous solution of nonamine hydrochloride, and add NaOH to neutralize the pH =7, extracted with anhydrous ether to obtain nonylamine with a yield of 60%.

Embodiment 2N, the synthesis of N-dimethyl tridecyl tertiary amine

0.6 mol of α-chlorotetradecanoic acid and 3.6 mol of dimethylamine (30% ethanol solution) were added into the autoclave, sealed and mixed evenly, and reacted at a constant temperature of 120° C. for 14 hours. After the reaction was completed, the excess dimethylamine was distilled off under reduced pressure, then added to a closed high-temperature reaction kettle, and reacted at 250° C. for 4 hours. After the reaction is completed, the solvent ethanol in the product is removed by rotary evaporation and dried, adding hydrochloric acid to make the system pH<2; adding petroleum ether (30-60°C) to extract and separate the fatty acid to obtain N, N dimethyl tridecyl tertiary amine hydrochloride The aqueous salt solution was neutralized to pH=7 by adding NaOH, and extracted with anhydrous ether to obtain N,N dimethyltridecyl tertiary amine with a yield of 73%.

The synthesis of embodiment 3N-methyl mixed fatty secondary amine

With 0.2mol α-bromococoic acid and the methylamine (40% ethanolic solution) that contains 0.8mol, fasten still lid, 105 ℃ of constant temperature stirring reactions 8 hours, after reaction finishes, add the pH= of NaOH adjustment solution From 11 to 12, unreacted methylamine was removed by evaporation under reduced pressure, and the reaction was continued at 280° C. for 6 hours in a high-temperature closed reaction kettle to obtain N-methyl mixed fatty secondary amine. The purification steps were the same as in Example 2.

The synthesis of embodiment 4N-propyl hexacylamine

Take 0.3 mol of α-iodoceroic acid (α-iodohexacanoic acid) and 3 mol of n-propylamine, quickly tighten the lid of the kettle, and stir at a constant temperature of 80°C for 6 hours. After the reaction, add NaOH to adjust the pH of the solution to 11 ~12, evaporated under reduced pressure to remove unreacted n-propylamine, and continued the reaction in a high-temperature closed reaction kettle at 230°C for 5 hours to obtain N-propylhexacylamine. The purification steps were the same as in Example 2. The yield of N-propylhexacylamine was 64%.

Claims (3)

1. A preparation method of high-grade fatty amine, which is characterized in that α-halogenated fatty acid is used as raw material, and high-grade fatty amine is prepared through two simple reactions of aminolysis and decarboxylation, and the synthetic route is as follows: Using ethanol or water as a solvent, put α-halogenated fatty acid and lower amine in a molar ratio of 1:3~10 into a normal pressure reactor or an autoclave reactor, stir at a constant temperature of 60~120°C for 3~14 hours, and remove After removing the unreacted lower amine and solvent, put it into a high-temperature autoclaved reaction kettle, and react at 200-300°C for 3-6 hours. After the reaction is completed, the solvent is distilled off under reduced pressure and dried, then acidified by adding hydrochloric acid, extracted and separated by petroleum ether (30-60°C) to obtain fatty amine hydrochloride, neutralized by adding NaOH to pH = 7, anhydrous diethyl ether Purified higher aliphatic amines are obtained by extraction. the 2. the preparation method of higher aliphatic amine according to claim 1 is characterized in that described α-halogenated fatty acid is expressed with following general formula: In the formula, X is Cl, Br or I; R ₁ is a C ₈ ~ C ₃₈ saturated linear or branched, single-carbon or mixed-carbon hydrocarbon group; that is, the general formula is C _n H _2n+1 where n=0～ 38. 3. the preparation method of higher fatty amine according to claim 1 is characterized in that described lower amine is expressed with following general formula: In the formula, R ₂ and R ₃ are saturated linear or branched hydrocarbon groups, that is, the general formula is C _n H _2n+1 , where n=0, 1, 2 or 3.