阅读说明：本技术 一种己二胺关键中间体反应残渣回收利用并联产羧酸的方法 (Method for recycling reaction residues of key intermediate of hexamethylene diamine and co-producing carboxylic acid ) 是由 王刚 聂庆超 王根林 丁克鸿 徐林 汪洋 殷剑虎 陈耀坤 李良善 何成义 于 2020-06-24 设计创作，主要内容包括：本发明涉及一种己二胺关键中间体反应残渣回收利用并联产羧酸的方法,将残渣与水通入第一固定床反应器中,进行解聚反应；然后,将所得解聚反应液经换热后通入第二固定床反应器中,进行水解反应；再将所得水解反应液进行加氢反应,反应结束后对所得加氢反应液进行负压蒸馏,脱去水后得到浓缩液；对所得浓缩液进行负压精馏,收集不同气相温度下的馏分,得到相应产品氨基己酸、正戊酸和正己酸。本发明有效地解决了现有己二胺生产普遍存在的关键中间体反应残渣污染问题,实现了己二胺关键中间体反应残渣的回收及资源化利用,得到高附加值产品,降低生产成本并增加经济效益；而且,减少三废排放量,大幅降低对环境的污染,为绿色安全生产提供保障。(The invention relates to a method for recycling reaction residues of a key intermediate of hexamethylenediamine and co-producing carboxylic acid, wherein the residues and water are introduced into a first fixed bed reactor to carry out depolymerization reaction; then, introducing the obtained depolymerization reaction liquid into a second fixed bed reactor after heat exchange for hydrolysis reaction; then carrying out hydrogenation reaction on the obtained hydrolysis reaction liquid, carrying out negative pressure distillation on the obtained hydrogenation reaction liquid after the reaction is finished, and dewatering to obtain a concentrated solution; and carrying out negative pressure rectification on the obtained concentrated solution, and collecting fractions at different gas phase temperatures to obtain corresponding products of aminocaproic acid, n-pentanoic acid and n-hexanoic acid. The method effectively solves the problem of pollution of the reaction residues of the key intermediates commonly existing in the existing hexamethylenediamine production, realizes the recovery and resource utilization of the reaction residues of the hexamethylenediamine key intermediates, obtains products with high added value, reduces the production cost and increases the economic benefit; and the discharge amount of three wastes is reduced, the pollution to the environment is greatly reduced, and the guarantee is provided for green and safe production.)

1. A method for recycling reaction residues of key hexamethylenediamine intermediates and coproducing carboxylic acid is characterized by comprising the following steps:

(1) introducing the residue and water into a first fixed bed reactor for depolymerization;

(2) introducing the depolymerization reaction liquid obtained in the step (1) into a second fixed bed reactor after heat exchange for hydrolysis reaction;

(3) carrying out hydrogenation reaction on the hydrolysis reaction liquid obtained in the step (2), carrying out negative pressure distillation on the obtained hydrogenation reaction liquid after the reaction is finished, and dewatering to obtain a concentrated solution;

(4) and (4) carrying out negative pressure rectification on the concentrated solution obtained in the step (3), and collecting fractions at different gas phase temperatures to obtain products of aminocaproic acid, n-pentanoic acid and n-hexanoic acid.

2. The method for recycling and co-producing carboxylic acid from reaction residues of key intermediate of hexamethylene diamine as claimed in claim 1, wherein in the step (1), the first fixed bed reactor is filled with solid catalyst.

3. The method for recycling reaction residues of key intermediate of hexamethylene diamine and coproducing carboxylic acid as claimed in claim 2, wherein the solid catalyst filled in the first fixed bed reactor is Al₂O₃、SiO₂、MnO₂、BF₃/Al₂O₃、CsF/ZrO₂And KNH₂/Al₂O₃Any one or a combination of any two or more of them.

4. The method for recycling reaction residues of key hexamethylene diamine and coproducing carboxylic acid as claimed in claim 1, wherein in the step (1), the mass ratio of the residues to water is (0.1-5): 1; in the first fixed bed reactor, the reaction temperature is 150-400 ℃, the reaction pressure is 0-15.0 MPa, and the space velocity of the total raw materials is 0.01h^-1～20.0h^-1。

5. The method for recycling and co-producing carboxylic acid from reaction residues of key intermediate of hexamethylene diamine as claimed in claim 1, wherein in the step (2), the second fixed bed reactor is filled with solid acid.

6. The method for recycling reaction residues of key intermediate of hexamethylene diamine and coproducing carboxylic acid as claimed in claim 5, wherein the solid acid filled in the second fixed bed reactor is TiO₂、ZrO₂、B₂O₃、Nb₂O₅、AlPO₄、BPO₄、Al₂O₃/B₂O₅、SiO₂-Al₂O₃、ZrO₂-SiO₂And NiSO₄、Zr(SO₄)₂Any one or a combination of any two or more of them.

7. The recycling of reaction residues of key intermediate of hexamethylenediamine according to claim 1The method for co-producing carboxylic acid is characterized in that in the step (2), in the second fixed bed reactor, the reaction temperature is 50-200 ℃, the reaction pressure is 0-15.0 MPa, and the space velocity of the total raw material is 0.01h^-1～20.0h^-1。

8. The method for recycling the reaction residue of the key intermediate of hexamethylene diamine and co-producing carboxylic acid as claimed in claim 1, wherein the operation pressure for performing the negative pressure distillation in the step (3) is 1kPa to 10 kPa.

9. The method for recycling the reaction residue of the key intermediate of hexamethylene diamine and coproducing carboxylic acid as defined in claim 1, wherein the operation pressure for carrying out the negative pressure rectification in the step (4) is 0kPa to 3 kPa.

10. The method for recycling reaction residues of key intermediate of hexamethylene diamine and co-producing carboxylic acid as claimed in any one of claims 1 to 9,

in the step (1), the residue and water are simultaneously and continuously introduced into the first fixed bed reactor, the residue and water are input from the lower end of the first fixed bed reactor, depolymerization reaction is carried out, and a depolymerization reaction liquid material obtained after the depolymerization reaction is output from the upper end of the first fixed bed reactor;

in the step (2), the depolymerization reaction liquid obtained in the step (1) is subjected to heat exchange by a heat exchanger and then continuously enters from the lower end of the second fixed bed reactor to carry out hydrolysis reaction, and the hydrolysis reaction liquid material obtained after the reaction is output from the upper end of the second fixed bed reactor;

in the step (3), the hydrolysis reaction solution obtained in the step (2) is put into an autoclave and subjected to hydrogenation reaction with hydrogen.

Technical Field

The invention relates to the technical field of organic chemical industry, in particular to a method for recycling reaction residues of a key intermediate of hexamethylene diamine and co-producing carboxylic acid.

Background

The hexamethylene diamine has wide application and is a very important organic raw material in the field of chemical production, for example, the hexamethylene diamine is used for preparing nylon 66 salt, the nylon 66 is the polyamide which realizes the industrial mark at first, and the nylon 66 is parallel to nylon 6 and is two most important polyamide substances; for another example, the application of hexamethylenediamine in the field of polyamide is researched, developed and expanded, so that products such as nylon 610 and nylon 612 can be successfully manufactured, and meanwhile, the hexamethylenediamine is also developed and applied in aspects such as polyurethane foam plastics, coatings, epoxy resin curing agents, organic cross-linking agents, pesticides, iron ore and copper ore flotation agents and the like.

One of the main production methods of hexamethylene diamine is caprolactam ammoniation, which is characterized in that caprolactam and ammonia react under a catalyst to generate a key intermediate of aminocapronitrile, the formed aminocapronitrile is rectified and separated to prepare high-purity aminocapronitrile, and the aminocapronitrile is subjected to hydrogenation chemical reaction to obtain the needed hexamethylene diamine product. In the caprolactam ammonification method, a small amount of free caprolactam and aminocapronitrile can be polymerized to generate polymers in the reaction and post-treatment processes, and finally, residues are formed to be solid and waste, so that the environment is seriously influenced, and meanwhile, the production efficiency and the product quality are also influenced. Therefore, research and development of a method for solving the solid waste pollution of the residue in the production of hexamethylenediamine are required.

Disclosure of Invention

The invention aims to provide a method for recycling reaction residues of a key intermediate of hexamethylene diamine and co-producing carboxylic acid aiming at the problems in the prior art, so as to realize the resource utilization of the solid wastes of the residues, reduce the discharge amount of the solid wastes in the production process of the hexamethylene diamine, reduce the cost, improve the economic benefit and provide guarantee for green, environment-friendly and safe production.

The technical scheme for solving the problems is as follows: a method for recycling reaction residues of key hexamethylenediamine intermediates and coproducing carboxylic acid comprises the following steps:

(1) introducing the residue and water into a first fixed bed reactor for depolymerization;

(2) introducing the depolymerization reaction liquid obtained in the step (1) into a second fixed bed reactor after heat exchange for hydrolysis reaction;

(3) carrying out hydrogenation reaction on the hydrolysis reaction liquid obtained in the step (2), carrying out negative pressure distillation on the obtained hydrogenation reaction liquid after the reaction is finished, and dewatering to obtain a concentrated solution;

(4) and (4) carrying out negative pressure rectification on the concentrated solution obtained in the step (3), and collecting fractions at different gas phase temperatures to obtain products of aminocaproic acid, n-pentanoic acid and n-hexanoic acid.

Further, in the method for recycling reaction residues of key intermediate of hexamethylene diamine and coproducing carboxylic acid, in the step (1), the first fixed bed reactor is filled with a solid catalyst.

Preferably, in the method for recycling reaction residues of key intermediate of hexamethylene diamine and coproducing carboxylic acid, the solid catalyst filled in the first fixed bed reactor is Al₂O₃、SiO₂、MnO₂、BF₃/Al₂O₃、CsF/ZrO₂And KNH₂/Al₂O₃Any one or a combination of any two or more of them.

Further, in the method for recycling reaction residues of key hexamethylenediamine intermediates and coproducing carboxylic acid, in the step (1), the mass ratio of the residues to water is (0.1-5): 1; in the first fixed bed reactor, the reaction temperature is 150-400 ℃, the reaction pressure is 0-15.0 MPa, and the space velocity of the total raw materials is 0.01h^-1～20.0h^-1。

Further, in the method for recycling reaction residues of key intermediate of hexamethylene diamine and co-producing carboxylic acid, in the step (2), the second fixed bed reactor is filled with solid acid.

Preferably, in the method for recycling reaction residues of key intermediate of hexamethylene diamine and coproducing carboxylic acid, the solid acid filled in the second fixed bed reactor is TiO₂、ZrO₂、B₂O₃、Nb₂O₅、AlPO₄、BPO₄、Al₂O₃/B₂O₅、SiO₂-Al₂O₃、ZrO₂-SiO₂And NiSO₄、Zr(SO₄)₂Any one or any two ofCombinations of the above.

Further, in the method for recycling the reaction residues of the key intermediate of the hexamethylenediamine and coproducing the carboxylic acid, in the step (2), in the second fixed bed reactor, the reaction temperature is 50-200 ℃, the reaction pressure is 0-15.0 MPa, and the space velocity of the total raw materials is 0.01h^-1～20.0h^-1。

Further, in the method for recycling the reaction residue of the key intermediate of hexamethylenediamine and co-producing carboxylic acid according to the present invention, in the step (3), the operating pressure at which the negative pressure distillation is performed is 1kPa to 10 kPa.

Further, in the method for recycling the reaction residue of the key intermediate of the hexamethylenediamine and coproducing the carboxylic acid, in the step (4), the operation pressure for performing the negative pressure rectification is 0 to 3 kPa.

Further, in the method for recycling reaction residues of the key intermediate of hexamethylenediamine and co-producing carboxylic acid, in the step (1), the residues and water are simultaneously and continuously introduced into the first fixed bed reactor, the residues and the water are input from the lower end of the first fixed bed reactor and are subjected to depolymerization reaction, and a depolymerization reaction liquid material obtained after the reaction is output from the upper end of the first fixed bed reactor; in the step (2), the depolymerization reaction liquid obtained in the step (1) is subjected to heat exchange by a heat exchanger and then continuously enters from the lower end of the second fixed bed reactor to carry out hydrolysis reaction, and the hydrolysis reaction liquid material obtained after the reaction is output from the upper end of the second fixed bed reactor; in the step (3), the hydrolysis reaction solution obtained in the step (2) is put into an autoclave and subjected to hydrogenation reaction with hydrogen.

Compared with the prior art, the invention has the beneficial effects that: the process design is innovative, the problem of pollution of the reaction residues of the key intermediate commonly existing in the existing hexamethylenediamine production is effectively solved, the recovery and resource utilization of the reaction residues of the hexamethylenediamine key intermediate are creatively realized, the discharge amount of three wastes is reduced, and the guarantee is provided for the green environmental protection of the hexamethylenediamine production; moreover, the product obtained by the method has high value, is used as a byproduct high added-value product for producing the hexamethylene diamine, is beneficial to reducing the overall production cost and increasing the economic benefit; in addition, the method has the advantages of simple operation and less side reaction, and the residual materials after the product is collected can be recycled, thereby greatly reducing the pollution to the environment.

Detailed Description

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the present invention were all purchased from commercial sources.

The invention discloses a method for recycling reaction residues of a key intermediate of hexamethylene diamine and coproducing carboxylic acid, which comprises the following steps:

(1) introducing the residue and water into a first fixed bed reactor for depolymerization;

(2) introducing the depolymerization reaction liquid obtained in the step (1) into a second fixed bed reactor after heat exchange for hydrolysis reaction;

(3) carrying out hydrogenation reaction on the hydrolysis reaction liquid obtained in the step (2), carrying out negative pressure distillation on the obtained hydrogenation reaction liquid after the reaction is finished, and dewatering to obtain a concentrated solution;

(4) and (4) carrying out negative pressure rectification on the concentrated solution obtained in the step (3), and collecting fractions at different gas phase temperatures to obtain products of aminocaproic acid, n-pentanoic acid and n-hexanoic acid.

In the method for recycling the reaction residues of the key intermediate of hexamethylenediamine and coproducing carboxylic acid, in order to fully react the raw material materials involved in each step, preferably, each reactant material is continuously input from the lower end of a reactor, and the product material obtained by each reaction is output from the upper end of the corresponding reactor, specifically, in the step (1), the residues and water are continuously input into the first fixed bed reactor at the same time, the residues and the water are input from the lower end of the first fixed bed reactor to carry out depolymerization reaction, and the depolymerization reaction liquid material obtained after the reaction is output from the upper end of the first fixed bed reactor; in the step (2), the depolymerization reaction liquid obtained in the step (1) is subjected to heat exchange by a heat exchanger and then continuously enters from the lower end of the second fixed bed reactor to carry out hydrolysis reaction, and the hydrolysis reaction liquid material obtained after the reaction is output from the upper end of the second fixed bed reactor; in the step (3), the hydrolysis reaction liquid obtained in the step (2) is put into an autoclave and is subjected to hydrogenation reaction with hydrogen, so that the reaction efficiency is improved. Specifically, specifications of the first fixed bed reactor and the second fixed bed reactor are selected according to specific working conditions, preferably, the inner diameter of the first fixed bed reactor is 10mm, and the length of the first fixed bed reactor is 1000 mm; the inner diameter of the second fixed bed reactor is 20mm, and the length of the second fixed bed reactor is 1000 mm.

In the method for recycling the reaction residue of the key intermediate of hexamethylenediamine and coproducing carboxylic acid, in order to improve the recycling efficiency, preferably, in the step (1), the first fixed bed reactor is filled with a solid catalyst; preferably, the solid catalyst filled in the first fixed bed reactor is Al₂O₃、SiO₂、MnO₂、BF₃/Al₂O₃、CsF/ZrO₂And KNH₂/Al₂O₃Any one or a combination of any two or more of them; more preferably, in the step (1), the mass ratio of the residue to water is (0.1-5): 1; in the first fixed bed reactor, the reaction temperature is 150-400 ℃, the reaction pressure is 0-15.0 MPa, and the space velocity of the total raw materials is 0.01h^-1～20.0h^-1(ii) a So as to ensure that the depolymerization reaction is carried out fully and efficiently. Preferably, in the step (2), the second fixed bed reactor is filled with a solid acid; preferably, the solid acid filled in the second fixed bed reactor is TiO₂、ZrO₂、B₂O₃、Nb₂O₅、AlPO₄、BPO₄、Al₂O₃/B₂O₅、SiO₂-Al₂O₃、ZrO₂-SiO₂And NiSO₄、Zr(SO₄)₂Any one or a combination of any two or more of them; more preferably, in the step (2), in the second fixed bed reactor, the reaction temperature is 50-200 ℃, the reaction pressure is 0-15.0 MPa, and the space velocity of the total raw materials is 0.01h^-1～20.0h^-1(ii) a So that the hydrolysis is sufficiently efficient. Preferably, in saidIn the step (3), the operation pressure is 1 kPa-10 kPa during the negative pressure distillation, so as to ensure the distillation effect. Preferably, in the step (4), the negative pressure rectification is performed at an operating pressure of 0 to 3kPa so that each product fraction is sufficiently collected.

In the method for recycling the reaction residues of the key intermediate of the hexamethylene diamine and coproducing the carboxylic acid, the raw material residues in the step (1) refer to the reaction residues of the key intermediate in the production process of the hexamethylene diamine, mainly comprise distillation still residues obtained after caprolactam and aminocapronitrile are recycled from reaction liquid of reaction of caprolactam and ammonia gas, and the residues mainly comprise condensation products of the caprolactam and the aminocapronitrile and caprolactam polymers with different polymerization degrees. In order to reduce the pollution of residue discharge and realize the recycling of residue, in view of the high value of Aminocaproic Acid (Aminocaproic Acid), which is an antifibrinolytic drug, fibrinogen is specifically bound to fibrin through lysine binding sites in the molecular structure thereof and then becomes plasmin under the action of an activator, which can cleave peptide chains of arginine and lysine in fibrin to form fibrin degradation products, and dissolve blood clots. The invention innovatively designs a recycling process method for the reaction residue of the key intermediate of hexamethylene diamine, belongs to a green and safe process, and obtains high value-added products such as aminocaproic acid, n-valeric acid and n-hexanoic acid by recycling the residue through depolymerization, hydrolysis, hydrogenation and the like, so that the three wastes are reduced, the pollution is reduced, the environmental protection effect is enhanced, and the economic benefit is improved for enterprises while the solid waste is recycled.

The present invention will be further described in more detail with reference to more specific application examples, but the present invention is not limited to any examples.