Process for the co-production of hexamethylenediamine and cyclohexylideneimine

Abstract

The present application relates to the chemical technology field, disclose a kind of hexamethylene diamine and cyclohexyl hydrazine co-production method, the method comprises: (1) under the ammonia reaction condition and the first solvent exists, hexanediol and ammonia are reacted to obtain ammonia reaction product, and the ammonia reaction product is separated to obtain cyclohexyl hydrazine, hexamethylene diamine, amino containing hexanol material and carbon containing dodecylamine material;At least part of amino containing hexanol material is returned to ammonia reaction, and the mass ratio of amino containing hexanol material in ammonia reaction and fresh hexanediol is 0.3-20;(2) under the ammonolysis reaction condition and the second solvent exists, carbon dodecylamine in carbon containing dodecylamine material occurs ammonolysis reaction to obtain ammonolysis product.The method of the present application can flexibly adjust the yield of hexamethylene diamine and cyclohexyl hydrazine under the condition of ensuring that the total yield of hexamethylene diamine and cyclohexyl hydrazine is relatively high.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and specifically to a method for the co-production of hexamethylenediamine and cycloheximine. Background Technology

[0002] Polyhexamethylene adipamide, also known as polyamide 66 (PA66) or nylon 66, is produced by the polycondensation reaction of hexamethylenediamine and adipic acid. Currently, hexamethylenediamine is obtained by hydrogenating adiponitrile. Industrial technologies for adiponitrile include butadiene hydrocyanation, acrylonitrile electrolytic dimerization, and high-temperature amination with adipic acid. In 2019, global adiponitrile production reached 1.746 million tons per year, with capacity mainly concentrated in four companies: Invista, Ascend, Solvay, and Asahi Kasei. Invista has an adiponitrile capacity of 1.04 million tons, making it the world's largest adiponitrile producer; Ascend has a capacity of 400,000 tons, ranking second; Solvay has a capacity of 260,000 tons; and Asahi Kasei has a 43,000-ton adiponitrile plant.

[0003] Adiponitrile production technology is monopolized by Invista and Rhodia, with Invista almost monopolizing global adiponitrile production and trade. Currently, China has not yet achieved self-sufficiency in adiponitrile supply, and all products are imported, hindering the development of the domestic hexamethylenediamine (HMDA) industry. From a policy perspective, the Nylon 66 industry is subject to anti-dumping policies. my country's HMDA imports are constrained by foreign policies, making it one of the key chemicals in the engineering plastics industry chain that is heavily reliant on international developments, given the current international trade situation.

[0004] Cyclohexylimine (hexamethyleneimine) is a seven-membered heterocyclic imine compound, an important chemical intermediate, and a high-tech fine organic chemical. It can be used not only as a pharmaceutical and pesticide intermediate but also in many other fields such as textiles, rubber, fibers, resins, metal corrosion protection, waste treatment, and molecular sieves. Due to the difficulty in selecting catalysts for its synthesis, only a few countries in the world are capable of producing cyclohexylimine. For a long time, DuPont monopolized the technology for cyclohexylimine production, recovering it from a byproduct of nylon production. Its original production capacity was 3,600 tons per year, but in recent years, production has continuously expanded, currently reaching 15,000 tons per year. Mitsubishi Chemical Corporation of Japan uses caprolactam hydrogenation to produce cyclohexylimine, and in 1982, it pioneered an industrial-scale plant with an annual production capacity of 4,000 tons.

[0005] Some domestic cyclohexylimine production methods suffer from various problems, including environmental pollution, difficulty in catalyst recovery and reuse, and low product yield. The industrial synthesis route for cyclohexylimine is complex, highly corrosive and toxic, and requires high investment and maintenance costs for storage and synthesis equipment, resulting in a high price and limiting its large-scale application in many fields. The cyclohexylimine industry is still in its growth stage, with relatively high barriers to entry. Therefore, large-scale production of cyclohexylimine by domestic enterprises faces certain difficulties. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of insufficient production capacity of hexamethylenediamine and cyclohexylimine in the prior art, and to provide a method for the co-production of hexamethylenediamine and cyclohexylimine.

[0007] To achieve the above objectives, the present invention provides a method for the co-production of hexamethylenediamine and cyclohexylimine, the method comprising:

[0008] (1) Under ammoniation reaction conditions and in the presence of a first solvent, hexanediol and ammonia undergo an ammoniation reaction to obtain an ammoniation reaction product. The ammoniation reaction product is separated to obtain cycloheximine, hexanediamine, a material containing aminohexanol, and a material containing dodecylamine. At least a portion of the material containing aminohexanol is returned to the ammoniation reaction, and the mass ratio of the material containing aminohexanol returned to the ammoniation reaction to fresh hexanediol is controlled to be 0.3-20.

[0009] (2) Under ammonolysis reaction conditions and in the presence of a second solvent, the carbon-dodecylamine in the material containing carbon-dodecylamine undergoes an ammonolysis reaction to obtain the ammonolysis product.

[0010] The method for co-producing hexamethylenediamine and cycloheximine of the present invention has the following characteristics:

[0011] (1) By controlling the introduction of solvent in the ammoniation and ammonolysis reactions, the present invention avoids solid-phase crystallization and precipitation, and also avoids the huge investment caused by the need for full-process heat preservation measures in solvent-free systems.

[0012] (2) The method of this invention can break through the current situation where adiponitrile raw materials and technology are monopolized by foreign countries, enabling the localization of key raw materials for nylon 66. This process is inherently safe, does not involve highly toxic nitrile chemicals, has a simple technical route, and is environmentally friendly.

[0013] (3) This invention can fully utilize existing hexanediol resources, providing enterprises with a method for producing hexanediamine and cyclohexylimine through hydroammoniation of hexanediol. This simultaneously yields two high-value-added products with promising market prospects, improving the flexibility of the hexanediol amination unit. Enterprises can schedule production based on the market demand and price of hexanediamine and cyclohexylimine. Preferably, the obtained hexanediamine product has stable yield, high purity, high recovery rate, and few impurities; the co-produced cyclohexylimine product has high purity and few impurities.

[0014] (4) The method of the present invention can flexibly adjust the production of hexamethylenediamine and cyclohexylimine while ensuring a high total yield, thereby improving the enterprise's adaptability to the market and allowing for timely adjustments to production direction based on market demand. Furthermore, the method of the present invention is simple, easy to adjust, and highly adaptable. The method of the present invention also reduces wastewater discharge and improves the utilization rate of raw materials. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention;

[0016] Figure 2 This is a process flow diagram of Embodiment 2 of the present invention. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] In this invention, dodecylamine refers to an amine compound with 12 carbon atoms.

[0019] This invention provides a method for the co-production of hexamethylenediamine and cycloheximine, the method comprising:

[0020] (1) Under ammoniation reaction conditions and in the presence of a first solvent, hexanediol and ammonia undergo an ammoniation reaction to obtain an ammoniation reaction product. The ammoniation reaction product is separated to obtain cycloheximine, hexanediamine, a material containing aminohexanol, and a material containing dodecylamine. At least a portion of the material containing aminohexanol is returned to the ammoniation reaction, and the mass ratio of the material containing aminohexanol returned to the ammoniation reaction to fresh hexanediol is controlled to be 0.3-20.

[0021] (2) Under ammonolysis reaction conditions and in the presence of a second solvent, the carbon-dodecylamine in the material containing carbon-dodecylamine undergoes an ammonolysis reaction to obtain the ammonolysis product.

[0022] According to the present invention, preferably, the mass ratio of the aminohexanol-containing material to fresh hexanediol is controlled to be 0.5-15.

[0023] According to the present invention, preferably, a portion of the cyclohexylimine is returned to the amination reaction, the remaining cyclohexylimine is extracted as a product, and the weight ratio of the cyclohexylimine extracted as a product to the cyclohexylimine returned to the amination reaction is controlled to be 0.01-0.75, preferably 0.05-0.7.

[0024] It should be noted that, at the beginning of the reaction, the amount of cyclohexylimine and aminohexanol produced by the ammoniation reaction is relatively small, and the amount of circulating solvent in the system is also relatively small. Therefore, in the initial stage of the reaction, all cyclohexylimine, circulating solvent, and aminohexanol-containing streams are returned to the ammoniation reaction. However, in the stable operating stage of the reaction, the amount of cyclohexylimine and aminohexanol produced by the ammoniation reaction is larger, and the amount of circulating solvent in the system is also larger. At this time, some of the generated aminohexanol can be returned to the ammoniation reaction, some of the first solvent can be returned to the ammoniation reaction and partially enter the ammonolysis reaction, some of the cyclohexylimine can be returned to the ammoniation reaction, and the remainder is collected as product. The mass ratio of the aminohexanol-containing stream to fresh hexanediol, and the mass ratio of cyclohexylimine extracted as product to cyclohexylimine returned to the ammoniation reaction given in the embodiments of this application are all mass ratios during the stable operating stage of the reaction.

[0025] Compared to separately returning the aminohexanol-containing material or separately returning cyclohexylimine to the ammoniation reaction, in a preferred embodiment of the present invention, by controlling the mass ratio of the aminohexanol-containing material to fresh hexanediol, and by controlling the weight ratio of the cyclohexylimine extracted as a product to the cyclohexylimine returned to the ammoniation reaction, the total yield of cyclohexylimine and hexanediamine can be higher.

[0026] In this invention, the catalyst used in the ammoniation reaction can be a commonly used ammoniation reaction catalyst in the art, such as CN114433086A. Preferably, the catalyst comprises a support and an active component supported on the support, and optional auxiliary agents. The support includes a dopant element, alumina, and optional other supports, wherein the other supports are selected from at least one of silica, molecular sieves, and diatomaceous earth; the percentage of pore volume with a pore size less than 7.5 nm in the support is less than 20%, the percentage of pore volume with a pore size less than 9 nm in the support is less than 40%, and the percentage of pore volume with a pore size greater than 27 nm in the support is less than 5%; the ammonia adsorption capacity of the support is 0.3-0.6 mmol / g; the L acid in the support accounts for more than 90% of the sum of L acid and Brønsted acid; and the active component is cobalt and / or nickel.

[0027] According to the ammoniation catalyst of the present invention, preferably, the support is selected from alumina doped with at least one of silica, molecular sieve and diatomaceous earth, as well as undoped alumina. The content of alumina support in the support accounts for more than 65% by weight of the total amount of alumina support and other supports, preferably more than 75% by weight.

[0028] According to the ammoniation catalyst of the present invention, preferably, the support may further include a dopant element, the content of which is 0.05-3% by weight of the total weight of the components other than the dopant element in the support, more preferably 0.08-2% by weight, and even more preferably 0.1-1.5% by weight. The components other than the dopant element mainly refer to alumina in the support and optional other supports.

[0029] According to the ammoniation catalyst of the present invention, preferably, the impurity element added to the support is derived from anion ions that do not contain chloride ions. Since the impurity element is introduced during the preparation of the support, it mainly exists in the bulk phase of the support.

[0030] According to the ammoniation catalyst of the present invention, preferably, the acid radical ion can be selected from at least one of non-metallic acid radical ions, more preferably at least one of borate ion, fluoride ion, phosphate ion, sulfate ion and selenate ion. The dopant element is preferably selected from at least one of boron, fluorine, phosphorus, sulfur and selenium.

[0031] According to the ammoniation catalyst of the present invention, preferably, the percentage of pore volume with a pore size less than 7.5 nm in the support is 5-17%, more preferably 5-10%; the percentage of pore volume with a pore size greater than or equal to 7.5 nm and less than 9 nm in the support is 5-17%; the percentage of pore volume with a pore size greater than or equal to 9 nm and less than or equal to 27 nm in the support is 61-89.5%; and the percentage of pore volume with a pore size greater than 27 nm in the support is 0.5-5%, more preferably 0.5-3%. The inventors of the present invention have discovered that the catalyst with a pore structure satisfying this preferred embodiment has superior catalytic performance.

[0032] According to the ammoniation reaction catalyst of the present invention, preferably, the ammonia adsorption capacity of the support is 0.3-0.5 mmol / g.

[0033] According to the ammoniation catalyst of the present invention, preferably, the L-acid in the support accounts for 92-100% of the sum of L-acid and Brønsted acid, more preferably 96-100%. The L-acid percentage is determined by pyridine probe adsorption spectroscopy.

[0034] According to the ammoniation catalyst of the present invention, preferably, the specific surface area of ​​the support is 105-220 m². 2 / g, wherein the pore volume of the carrier is 0.4-1.1 ml / g.

[0035] According to the ammoniation catalyst of the present invention, preferably, the content of the active component is 5-42 g, more preferably 10-35 g, relative to 100 g of the support, excluding dopant elements. According to the present invention, in order to better utilize the performance of the catalyst, optimize the reaction product ratio, and reduce unwanted side reactions, the catalyst may also contain an auxiliary agent. The auxiliary agent may be selected from at least one of Group VIB, Group VIIB, Group IB, Group IIB, and lanthanides, preferably at least one of Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, La, and Ce.

[0036] According to the ammoniation catalyst of the present invention, preferably, the content of the auxiliary agent can be 0-10g, more preferably 0.5-6g, relative to 100g of the carrier excluding dopant elements.

[0037] In this invention, there are no restrictions on the type of ammoniation reactor used for the ammoniation and ammonolysis reactions. Any reactor that can ensure stable operation of the reaction can be used, such as a fixed-bed reactor, a high-pressure reactor, a fluidized-bed reactor, a trickle-bed reactor, etc.

[0038] According to the present invention, preferably, the ammoniation reaction is carried out in the presence of hydrogen, with a hydrogen:ammonia:hexanediol molar ratio of 0.1-11:17-65:1, preferably 0.2-6:21-55:1; the ammoniation reaction temperature is 110-220°C, preferably 120-210°C; the ammoniation reaction pressure is 6.5-17 MPaG, preferably 8-15 MPaG; and the liquid hourly space velocity (LHSV) of fresh hexanediol is 0.06-9 h⁻¹. -1 The preferred time is 0.07-3.7h. -1 .

[0039] According to the present invention, preferably, the separation of the ammoniation reaction products is carried out as follows: the ammoniation reaction products are fed into a light-light removal column for the separation of cyclohexylimine, a first solvent, and water, and the top of the light-light removal column yields a material containing cyclohexylimine, a first solvent, and water; the bottom material of the light-light removal column is fed into a distillation column for the separation of hexamethylenediamine, and the top of the distillation column yields hexamethylenediamine; the bottom material of the distillation column is fed into a heavy-weight removal column for the separation of aminohexanol, and the top of the heavy-weight removal column yields a material containing aminohexanol, while the bottom material yields a material containing dodecylamine.

[0040] According to the present invention, preferably, the operating conditions of the light-weight removal column include: a bottom temperature of 100-350°C, a top temperature of 35-70°C, a reflux ratio of 0.1-12, a top operating pressure of -0.1 MPaG to 1 MPaG, and 10-60 trays. More preferably, the operating conditions of the light-weight removal column include: a bottom temperature of 110-300°C, a top temperature of 40-60°C, a reflux ratio of 0.5-9, a top operating pressure of -0.09 MPaG to 0.5 MPaG, and 15-55 trays.

[0041] According to the present invention, preferably, the operating conditions of the distillation column include: a reboiler temperature of 130-350°C, a top temperature of 110-160°C, a reflux ratio of 0.5-15, a top operating pressure of -0.1 MPaG to 1 MPaG, and 20-60 trays. More preferably, the operating conditions of the distillation column include: a reboiler temperature of 140-300°C, a top temperature of 120-150°C, a reflux ratio of 1-12, a top operating pressure of -0.1 MPaG to 0.5 MPaG, and 25-55 trays.

[0042] According to the present invention, preferably, the operating conditions of the deweight removal column include: a reboiler temperature of 130-350°C, a top temperature of 140-200°C, a reflux ratio of 0.5-15, a top operating pressure of -0.1 MPaG to 0.5 MPaG, and 20-100 trays. More preferably, the operating conditions of the deweight removal column include: a reboiler temperature of 140-300°C, a top temperature of 150-190°C, a reflux ratio of 1-12, a top operating pressure of -0.1 MPaG to 0.3 MPaG, and 25-90 trays.

[0043] According to the present invention, preferably, the method further includes separating the material containing cyclohexylimine, a first solvent, and water obtained from the top of the light component removal tower: firstly, the material containing cyclohexylimine, solvent, and water is fed into a cyclohexylimine recovery tower, where the top of the tower yields a material containing cyclohexylimine and water, and the bottom of the tower yields a material containing solvent; then, the top material from the cyclohexylimine recovery tower and the azeotropic agent are fed into a dehydration tower for dehydration treatment, and the bottom material from the cyclohexylimine recovery tower is fed into a solvent recovery tower for solvent recovery. The operating conditions of the cyclohexylimine recovery tower include: bottom temperature of 100-270℃, top temperature of 10-70℃, reflux ratio of 0.2-12, top operating pressure of -0.1 MPaG to 1.5 MPaG, and 20-70 trays. The operating conditions for the dehydration tower include: a mass ratio of azeotropic agent to cycloheximine overhead material of 9-105:1; a reboiler temperature of 60-230℃; a top temperature of 30-60℃; a reflux ratio of 0.5-15; a top operating pressure of -0.08 MPaG to 2.5 MPaG; and 20-70 trays. The operating conditions for the solvent recovery tower include: a reboiler temperature of 100-240℃; a top temperature of 30-160℃; a reflux ratio of 0.5-13; a top operating pressure of -0.08 MPaG to 2 MPaG; and 20-80 trays. The azeotropic agent can be at least one of isopropyl ether and cyclohexane.

[0044] According to the present invention, preferably, the method further includes recovering hydrogen and ammonia from the ammoniation reaction products, and then sequentially feeding them into a light-light product removal column, a distillation column, and a heavy-light product removal column to separate cyclohexylimine, hexamethylenediamine, a product containing aminohexanol, and a product containing dodecylamine. More preferably, the method for recovering hydrogen and ammonia from the ammoniation reaction products includes removing hydrogen and ammonia by flash evaporation and recondensation, returning hydrogen in gaseous form to the ammoniation reactor via a compressor, and pumping liquid ammonia back to the ammoniation reactor.

[0045] In this invention, it is understood that since some ammonia and hydrogen are consumed in the ammoniation reaction, or some ammonia and hydrogen are released as purge gases during recovery, it is necessary to replenish fresh hexanediol in an appropriate amount while replenishing fresh ammonia and hydrogen during the ammoniation reaction to maintain the molar ratio of hexanediol (including freshly replenished hexanediol and hexanediol in the recycled material), ammonia and hydrogen in the ammoniation reaction system.

[0046] In this invention, the ammonolysis catalyst can be prepared by the following method:

[0047] (1) Preparation of carrier: A mixture of boehmite, silica sol and calcium nitrate is contacted with an aqueous solution containing nitric acid and phosphoric acid, and then kneaded, dried and calcined in sequence;

[0048] (2) The carrier is immersed in an aqueous solution containing nickel sulfate, lanthanum acetate and indium nitrate, dried at 100-140℃ for 2-6 hours, and then calcined at 350-450℃ for 2-6 hours.

[0049] According to the preparation method of the ammonolysis catalyst of this invention, preferably, the amount of silica sol is 0.6-0.8g, the amount of calcium nitrate is 0.1-0.4g, and the amount of aqueous solution containing nitric acid and phosphoric acid is 0.2-0.5g, relative to each gram of boehmite.

[0050] According to the preparation method of the ammonolysis catalyst of this invention, preferably, the aqueous solution containing nitric acid and phosphoric acid has a nitric acid content of 10-25% by weight and a phosphoric acid content of 5-15% by weight.

[0051] According to the preparation method of the ammonolysis catalyst of this invention, preferably, the drying temperature is 100-140℃ and the drying time is 1-6h.

[0052] According to the preparation method of the ammonolysis catalyst of this invention, preferably, the amount of nickel sulfate is 0.6-0.85g, the amount of lanthanum acetate is 0.06-0.08g, and the amount of indium nitrate is 0.055-0.065g relative to each gram of support.

[0053] According to the preparation method of the ammonolysis catalyst of this invention, preferably, the concentration of nickel sulfate in the aqueous solution containing nickel sulfate, lanthanum acetate and indium nitrate is 20-25% by weight, the concentration of lanthanum acetate is 1.5-2.5% by weight, and the concentration of indium nitrate is 1.5-2.5% by weight. The impregnation method is preferably an equal-volume impregnation method, and the impregnation can be carried out in multiple stages.

[0054] According to the present invention, preferably, the ammonolysis reaction is carried out in the presence of hydrogen and ammonia, wherein the molar ratio of hydrogen:ammonia:the material containing dodecylamine (calculated as bis(hexamethylene)triamine) is 0.2-15:17-105:1, preferably 0.13-13:20-95:1; the temperature of the ammonolysis reaction is 130-270°C, preferably 140-270°C; the pressure of the ammonolysis reaction is 9.5-23 MPaG, preferably 10.5-21 MPaG; and the liquid hourly space velocity (LHSV) of the material containing dodecylamine is 0.06-5 h⁻¹. -1 Preferred time: 0.07-3h -1 .

[0055] According to the present invention, preferably, the first solvent and the second solvent are each independently selected from at least one of tetrahydrofuran, 1,4-dioxane, n-hexane, cyclohexane and tert-butanol.

[0056] According to the present invention, preferably, the weight ratio of the first solvent to hexanediol is 0.25-10, more preferably 1.5-8.

[0057] According to the present invention, preferably, the weight ratio of the second solvent to the material containing dodecylamine is 0.25-8:1, more preferably 0.5-6:1.

[0058] According to the present invention, preferably, the first solvent and the second solvent are of the same type. The second solvent can be a freshly introduced solvent or a solvent material separated from the first solvent material in step (1). Generally, in the initial stage of the reaction, the amount of solvent in the system is small, and fresh solvent can be used at this time. After the reaction has been running for a period of time, the amount of solvent in the system is large, and the amount of solvent material separated from the first solvent material in step (1) can meet the requirements of the ammoniation and ammonolysis reactions. At this time, no fresh solvent is introduced into the system, and a portion of the first solvent material separated in step (1) is returned to the ammoniation reaction, and the other portion is used to dissolve the material containing dodecylamine. Since the circulating solvent in the reaction system will inevitably be lost, fresh solvent is replenished to the system periodically. That is, the first solvent or the second solvent separated from the ammoniation reaction product and the ammonolysis product is returned to the ammoniation reaction or the ammonolysis reaction after separation.

[0059] The present invention will be described in detail below through embodiments. In the following embodiments,

[0060] The composition of the product was analyzed by gas chromatography.

[0061] The yield of hexamethylenediamine = molar amount of hexamethylenediamine product ÷ molar amount of fresh hexanediol × 100%.

[0062] Yield of cyclohexylimine = molar amount of cyclohexylimine product ÷ molar amount of fresh hexanediol × 100%.

[0063] Preparation Example 1

[0064] Preparation of ammonolysis catalysts via a multi-step impregnation method:

[0065] (1) Weigh the pseudoboehmite (produced by the aluminum sulfate method, with a specific surface area of ​​310 m²). 2 The mixture consisted of 94.2 g of a mixture with a pore volume of 1.19 ml / g, 72.5 g of silica sol (JN-40), and 25.26 g of calcium nitrate tetrahydrate. The pseudoboehmite was placed in a kneader. The weighed silica sol and calcium nitrate tetrahydrate were added to 24.77 g of water to prepare a solution, which was then added to the kneader and thoroughly stirred with the pseudoboehmite. An aqueous solution consisting of 16.51 g of water, 4.71 g of nitric acid, and 2.83 g of phosphoric acid was then added and thoroughly stirred. The mixture was then kneaded and extruded into a clover shape, dried at 120°C for 4 hours, and then calcined in a muffle furnace at 900°C for 6 hours. After cooling, the carrier was obtained.

[0066] (2) Add 100.77g of nickel sulfate hexahydrate (industrial grade, purity 98%), 5.69g of lanthanum acetate monohydrate and 5.96g of indium nitrate pentahydrate to 134.78mL of water to prepare an aqueous solution. Load the solution onto the 73.25g carrier obtained in step (1) using the equal volume impregnation method in two separate steps. After each impregnation, dry at 120℃ for 4 hours. After the two impregnations are completed, calcine at 390℃ for 4 hours.

[0067] Example 1

[0068] (1) The ammoniation reaction is carried out under the action of an ammoniation catalyst and under hydrogen-containing conditions.

[0069] The ammoniation catalyst was prepared according to the method in Example 7 of CN114433086A. Before use, the catalyst was activated with hydrogen at 200°C for 2 hours. Hexanediol, solvent (cyclohexane), ammonia, and hydrogen were fed into an ammoniation reactor containing the ammoniation catalyst to induce an ammoniation reaction between hexanediol and ammonia. The ammoniation reaction temperature was 170°C, the ammoniation reaction pressure was 12.4 MPaG, and the fresh hexanediol liquid hourly space velocity (LHSV) was 1.5 h⁻¹. -1 The molar ratio of hydrogen, ammonia, solvent, and hexanediol in the feed material of the ammoniation reactor is controlled to be 2:30:3.56:1.

[0070] (2) Recovery of hydrogen and ammonia from the ammoniation reaction products

[0071] The ammoniation reaction products from the ammoniation reactor are fed into a hydrogen-ammonia recovery system, where hydrogen and ammonia are removed by flash evaporation and re-condensation. The hydrogen is returned to the ammoniation reactor in gaseous form via a compressor, and the liquid ammonia is pumped back to the ammoniation reactor. The main components of the circulating hydrogen are: ammonia 86.48 mol%, hydrogen 13.51 mol%; the main components of the circulating ammonia are: ammonia 94.75 mol%, water 2.34 mol%, cycloheximine 0.29 mol%, hexamethylenediamine 0.01 mol%, and cyclohexane 2.6 mol.

[0072] (3) Separation of the remaining amination reaction products

[0073] The reaction products after the removal of ammonia and hydrogen enter a distillation separation unit, which includes a light-light residue removal column, a rectification column, and a heavy-weight residue removal column connected in sequence. The light-light residue removal column removes cyclohexylimine, solvent, and water; the rectification column removes hexamethylenediamine; and the heavy-weight residue removal column removes dodecylamine to obtain aminohexanol and hexanediol. The operating conditions of the light-light residue removal column are: bottom temperature 265°C, top temperature 40°C, reflux ratio 6, top operating pressure 0.2 MPaG, and 50 trays. The top product from the light-light residue removal column contains cyclohexylimine, solvent, and water. The operating conditions of the rectification column are: bottom temperature 285°C, top temperature 120°C, reflux ratio 5, top operating pressure 0.1 MPaG, and 60 trays. The hexamethylenediamine product from the top of the rectification column has a main content of 99.8 wt%. The operating conditions of the deweighting tower include: bottom temperature of 300℃, top temperature of 150℃, reflux ratio of 4, top operating pressure of 0.1 MPaG, and 60 trays. The bottom material (containing dodecylamine) of the deweighting tower is sent to the ammonolysis unit. The top material containing aminohexanol from the deweighting tower is returned to the ammoniation reactor, and the weight ratio of the aminohexanol-containing material returned to the ammoniation reactor to fresh hexanediol is controlled at 0.87.

[0074] (4) Separation of materials containing cycloheximine, solvent and water.

[0075] First, the material containing cyclohexylimine, solvent, and water is fed into a cyclohexylimine recovery tower. The top of the tower yields a material containing cyclohexylimine and water, while the bottom yields a material containing solvent. Then, the top material from the cyclohexylimine recovery tower and the azeotropic agent (isopropyl ether) are fed into a dehydration tower for dehydration treatment. The bottom material from the cyclohexylimine recovery tower is fed into a solvent recovery tower for solvent recovery. The operating conditions for the cyclohexylimine recovery tower include: bottom temperature 160℃, top temperature 40℃, reflux ratio 5, top operating pressure 0.1 MPaG, and 60 trays. The operating conditions for the dehydration tower include: a mass ratio of azeotropic agent to the top material from the cyclohexylimine recovery tower of 70:1, bottom temperature 100℃, top temperature 40℃, reflux ratio 2, top operating pressure 0 MPaG, and 30 trays. The operating conditions of the solvent recovery tower include: bottom temperature of 200℃, top temperature of 100℃, reflux ratio of 2, top operating pressure of 1 MPaG, and 45 trays. A portion of the recovered solvent is returned to the ammoniation reaction, and a portion is returned to the ammonolysis reaction to maintain the molar ratio of solvent to hexanediol or dodecylamine-containing material in the inlet feed of the ammoniation and ammonolysis reactors.

[0076] The solvent recovered from the solvent recovery tower has a purity of 99.59 wt%, and the cyclohexylimine recovered from the dehydration tower has a purity of 97.47 wt%. Part of the cyclohexylimine is returned to the ammoniation reactor, and the remaining cyclohexylimine is collected as a product. The weight ratio of the cyclohexylimine extracted as a product to the cyclohexylimine returned to the ammoniation reaction is controlled to be 0.05.

[0077] (5) Ammonolysis reaction

[0078] The residue from the de-heavy tower in step (3) was transferred to an ammonolysis reactor containing the ammonolysis catalyst of Preparation Example 1. Hydrogen, liquid ammonia, and solvent (cyclohexane) were introduced, and under hydrogen-containing conditions, the dodecylamine was decomposed to generate hexamethylenediamine and cycloheximine. Some of the dodecylamine was converted into the heavier octadecylamine. The molar ratio of hydrogen:ammonia:solvent:dodecylamine-containing material (calculated as bis(hexamethylene)triamine) was 2:42:2:1. The ammonolysis reaction temperature was 175°C, the ammonolysis reaction pressure was 18 MPaG, and the liquid hourly space velocity (LHSV) of the dodecylamine-containing material was 0.5 h⁻¹. -1 The ammonolysis reaction products are separated to obtain ammonolysis recovery products and heavy components (carbooctadecylamine). The ammonolysis recovery products are returned to step (2), and the heavy components are discharged as waste liquid.

[0079] In this example, the purity of hexamethylenediamine was 99.8 wt%, and the purity of the co-produced cyclohexylimine was 97.47 wt%. The total molar yield of hexamethylenediamine and cyclohexylimine was 96.67%, and 1.6 kg of cyclohexylimine was produced per 100 kg of hexamethylenediamine.

[0080] Example 2

[0081] The process was carried out according to the method of Example 1, except that the catalyst for the ammoniation reaction was the catalyst prepared according to the method of Example 9 in CN114433086A; and the weight ratio of the aminohexanol-containing material returned to the ammoniation reactor to the fresh hexanediol was controlled to be 0.87; the weight ratio of the cycloheximine-containing material extracted as a product to the cycloheximine-containing material returned to the ammoniation reaction was controlled to be 0.05; in step (5), the ammonia and hydrogen obtained by the gas-liquid separation of the ammoniation reaction product were sent to step (2), and the liquid phase remaining after the gas-liquid separation was distilled to obtain a mixed product containing hexanediamine and cycloheximine, which was sent to step (3), and the remaining components were discharged as waste liquid.

[0082] In this example, the purity of hexamethylenediamine was 99.8 wt%, and the purity of the co-produced cyclohexylimine was 97.41 wt%. The total molar yield of hexamethylenediamine and cyclohexylimine was 97.69%. 2.1 kg of cyclohexylimine was co-produced from every 100 kg of hexamethylenediamine.

[0083] Example 3

[0084] (1) The ammoniation reaction is carried out under the action of an ammoniation catalyst and under hydrogen-containing conditions.

[0085] The ammoniation catalyst was prepared according to the method in Example 7 of CN114433086A. Before use, the catalyst was activated with hydrogen at 200°C for 2 hours. Hexanediol, ammonia, hydrogen, and solvent (cyclohexane) were fed into an ammoniation reactor containing the ammoniation catalyst to induce an ammoniation reaction between hexanediol and ammonia. The ammoniation reaction temperature was 165°C, the ammoniation reaction pressure was 12 MPa, and the fresh hexanediol liquid hourly space velocity (LHSV) was 1.5 h⁻¹. -1 The molar ratio of hydrogen, ammonia, solvent, and hexanediol in the feed material of the ammoniation reactor is controlled to be 1:30:3.56:1.

[0086] (2) Recovery of hydrogen and ammonia from the ammoniation reaction products

[0087] The ammoniation reaction products from the ammoniation reactor are fed into a hydrogen-ammonia recovery system, where hydrogen and ammonia are removed by flash evaporation and re-condensation. The hydrogen gas is returned to the ammoniation reactor in gaseous form via a compressor, and the liquid ammonia is pumped back to the ammoniation reactor. The main components of the circulating hydrogen are: ammonia 86.65 mol% and hydrogen 13.35 mol%. The main components of the circulating ammonia are: ammonia 94.99 mol%, water 2.25 mol%, cycloheximine 0.26 mol%, hexamethylenediamine 0.01 mol%, and cyclohexane 2.48 mol.

[0088] (3) Separation of the remaining amination reaction products

[0089] The reaction products after the removal of ammonia and hydrogen enter a distillation separation unit, which includes a light-light product removal column, a rectification column, and a heavy-light product removal column connected in sequence. The light-light product removal column removes cyclohexylimine, solvent, and water; the rectification column removes hexamethylenediamine; and the heavy-light product removal column removes dodecylamine to obtain aminohexanol and hexanediol. The operating conditions for the light-light product removal column are: bottom temperature 230°C, top temperature 50°C, reflux ratio 4, top operating pressure -0.09 MPaG, and 50 trays. The top product from the light-light product removal column contains cyclohexylimine, solvent, and water. The operating conditions for the rectification column are: bottom temperature 230°C, top temperature 120°C, reflux ratio 6, top operating pressure -0.09 MPaG, and 55 trays. The hexamethylenediamine product from the top of the rectification column has a main content of 99.8 wt%. The operating conditions of the heavy removal tower include: bottom temperature of 250℃, top temperature of 160℃, reflux ratio of 2, top operating pressure of -0.09 MPaG, and 60 trays. The bottom material of the heavy removal tower (containing dodecylamine) is sent to the ammonolysis unit. The top material containing aminohexanol from the heavy removal tower is returned to the ammoniation reactor, and the weight ratio of aminohexanol-containing material returned to the ammoniation reactor to fresh hexanediol is controlled at 0.79.

[0090] (4) Dehydration treatment of materials containing cycloheximine, solvent and water

[0091] First, the material containing cyclohexylimine, solvent, and water is fed into a cyclohexylimine recovery tower. The top of the tower yields a material containing cyclohexylimine and water, while the bottom yields a material containing solvent. Then, the top material from the cyclohexylimine recovery tower and the azeotropic agent (isopropyl ether) are fed into a dehydration tower for dehydration treatment. The bottom material from the cyclohexylimine recovery tower is fed into a solvent recovery tower for solvent recovery. The operating conditions for the cyclohexylimine recovery tower include: bottom temperature 100℃, top temperature 40℃, reflux ratio 2, top operating pressure -0.08 MPaG, and 50 trays. The operating conditions for the dehydration tower include: a mass ratio of azeotropic agent to the top material from the cyclohexylimine recovery tower of 60:1, a bottom temperature of 100℃, a top temperature of 40℃, a reflux ratio of 4, a top operating pressure of 0 MPaG, and 40 trays. The operating conditions of the solvent recovery tower include: bottom temperature of 230℃, top temperature of 110℃, reflux ratio of 3, top operating pressure of 1.3 MPaG, and 45 trays. A portion of the recovered solvent is returned to the ammoniation reaction, and a portion is returned to the ammonolysis reaction to maintain the molar ratio of solvent to hexanediol or dodecylamine-containing material in the inlet feed of the ammoniation and ammonolysis reactors.

[0092] The solvent recovered from the solvent recovery tower has a purity of 99.59 wt%, and the cyclohexylimine recovered from the dehydration tower has a purity of 98.11 wt%. Part of the cyclohexylimine is returned to the ammoniation reactor, and the remaining cyclohexylimine is collected as a product. The weight ratio of the cyclohexylimine extracted as a product to the cyclohexylimine returned to the ammoniation reaction is controlled to be 0.67.

[0093] (5) Ammonolysis reaction

[0094] The residue from the de-heavy tower in step (3) was transferred to an ammonolysis reactor containing the ammonolysis catalyst of Preparation Example 1. Hydrogen, liquid ammonia, and solvent (cyclohexane) were introduced, and under hydrogen-containing conditions, the dodecylamine was decomposed to generate hexamethylenediamine and cycloheximine. Some of the dodecylamine was converted into the heavier octadecylamine. The molar ratio of hydrogen:ammonia:solvent:dodecylamine-containing material (calculated as bis(hexamethylene)triamine) was 2:42:2:1. The ammonolysis reaction temperature was 175°C, the ammonolysis reaction pressure was 17.5 MPaG, and the liquid hourly space velocity (LHSV) of the dodecylamine-containing material was 1 h⁻¹. -1 The ammonolysis reaction products are separated to obtain ammonolysis recovery products and heavy components (carbooctadecylamine). The ammonolysis recovery products are returned to step (2), and the heavy components are discharged as waste liquid.

[0095] In this example, the purity of hexamethylenediamine is 99.8 wt%, and the purity of the co-produced cyclohexylimine is 98.11 wt%. The total molar yield of hexamethylenediamine and cyclohexylimine is 98.7%. Every 100 kg of hexamethylenediamine will produce 17.04 kg of cyclohexylimine.

[0096] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for the co-production of hexamethylenediamine and cyclohexylimine, characterized in that, The method includes: (1) Under the conditions of ammoniation reaction and in the presence of the first solvent, hexanediol and ammonia undergo an ammoniation reaction to obtain an ammoniation reaction product. The ammoniation reaction product is separated to obtain cyclohexylimine hexanediamine, a material containing aminohexanol, and a material containing dodecylamine. At least a portion of the material containing aminohexanol is returned to the ammoniation reaction, and the mass ratio of the material containing aminohexanol returned to the ammoniation reaction to fresh hexanediol is controlled to be 0.3-20. (2) Under ammonolysis reaction conditions and in the presence of a second solvent, the carbon-dodecylamine in the material containing carbon-dodecylamine undergoes an ammonolysis reaction to obtain the ammonolysis product; The ammonolysis catalyst in the ammonolysis reaction is prepared according to the following method: (1) Preparation of carrier: The mixture of boehmite, silica sol and calcium nitrate is contacted with an aqueous solution containing nitric acid and phosphoric acid, and then kneaded, dried and calcined in sequence; (2) The carrier is immersed in an aqueous solution containing nickel sulfate, lanthanum acetate and indium nitrate, dried at 100-140℃ for 2-6 hours, and then calcined at 350-450℃ for 2-6 hours.

2. The method according to claim 1, wherein, The mass ratio of aminohexanol-containing materials to fresh hexanediol should be controlled at 0.5-15.

3. The method according to claim 1, wherein, Part of the cyclohexylimine is returned to the amination reaction, and the remaining cyclohexylimine is extracted as a product. The weight ratio of the extracted cyclohexylimine to the cyclohexylimine returned to the amination reaction is controlled to be 0.01-0.

75.

4. The method according to claim 1, wherein, The ammoniation reaction is carried out in the presence of hydrogen gas, with a hydrogen:ammonia:hexanediol molar ratio of 0.1-11:17-65:

1. The ammoniation reaction temperature is 110-220℃, the pressure is 6.5-17 MPaG, and the liquid hourly space velocity (LHSV) of fresh hexanediol is 0.06-9 h⁻¹. -1 .

5. The method according to claim 4, wherein, The ammoniation reaction is carried out in the presence of hydrogen gas, with a hydrogen:ammonia:hexanediol molar ratio of 0.2-6:21-55:

1. The ammoniation reaction temperature is 120-210℃, the pressure is 8-15 MPaG, and the liquid hourly space velocity (LHSV) of fresh hexanediol is 0.07-3.7 h⁻¹. -1 .

6. The method according to any one of claims 1-5, wherein, The separation of the amination reaction products is as follows: the amination reaction products are fed into a light-light product removal column for the separation of cyclohexylimine, the first solvent, and water. The top of the light-light product removal column yields a material containing cyclohexylimine, the first solvent, and water. The bottom material of the light-light product removal column is fed into a distillation column for the separation of hexamethylenediamine. The top of the distillation column yields hexamethylenediamine. The bottom material of the distillation column is fed into a heavy product removal column for the separation of aminohexanol. The top of the heavy product removal column yields a material containing aminohexanol, and the bottom material yields a material containing dodecylamine.

7. The method according to claim 6, wherein, The operating conditions for the light component removal column include: bottom temperature of 100-350℃, top temperature of 35-70℃, reflux ratio of 0.1-12, top operating pressure of -0.1MPaG to 1MPaG, and 10-60 trays.

8. The method according to claim 6, wherein, The operating conditions of the distillation column include: bottom temperature of 130-350℃, top temperature of 110-160℃, reflux ratio of 0.5-15, top operating pressure of -0.1MPaG to 1MPaG, and 20-60 trays.

9. The method according to claim 6, wherein, The operating conditions for the deweight removal tower include: bottom temperature of 130-350℃, top temperature of 140-200℃, reflux ratio of 0.5-15, top operating pressure of -0.1MPaG to 0.5MPaG, and 20-100 trays.

10. The method according to claim 1, wherein, Ammonolysis is carried out in the presence of hydrogen and ammonia, with a molar ratio of hydrogen:ammonia:dodecylamine (based on bis(hexamethylene)triamine) of 0.2-15:17-105:

1. The temperature of the ammonolysis reaction is 130-270℃; the pressure of the ammonolysis reaction is 9.5-23 MPaG; and the liquid hourly space velocity (LHSV) of the dodecylamine-containing material is 0.06-5 h⁻¹. -1 .

11. The method according to claim 10, wherein, The ammonolysis reaction proceeds in the presence of hydrogen and ammonia, with a molar ratio of hydrogen:ammonia:dodecylamine (based on bis(hexamethylene)triamine) of 0.13-13:20-95:

1. The ammonolysis reaction occurs at a temperature of 140-265℃, a pressure of 10.5-21 MPaG, and a liquid hourly space velocity (LHSV) of 0.07-3 h⁻¹. -1 .

12. The method according to claim 1, wherein, The first solvent and the second solvent are each independently selected from at least one of tetrahydrofuran, 1,4-dioxane, n-hexane, cyclohexane and tert-butanol; And / or, the weight ratio of the first solvent to hexanediol is 0.25-10; And / or, the weight ratio of the second solvent to the material containing dodecylamine is 0.25-8:

1.

13. The method according to claim 12, wherein, The weight ratio of the first solvent to hexanediol is 1.5-8; And / or, the weight ratio of the second solvent to the material containing dodecylamine is 0.5-6:

1.

14. The method according to claim 12 or 13, wherein, The first solvent and the second solvent are of the same type.

15. The method according to claim 1, wherein, The first or second solvent obtained from the ammoniation reaction products and ammonolysis products is then returned to the ammoniation reaction or ammonolysis reaction after further separation.

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