A process for the co-production of N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether and bis(dimethylaminoethyl) ether

Abstract

This invention relates to the field of co-production synthesis technology and discloses a co-production synthesis process for N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether and bis(dimethylaminoethyl) ether. Using methylethanolamine, concentrated sulfuric acid, ethylene oxide, paraformaldehyde, and hydrogen as raw materials, the process involves sequential BMAEE synthesis, hydroxyethylation reaction, methylation reaction, and distillation purification steps to achieve co-production. Raney nickel is used as a catalyst in the methylation reaction. The Raney nickel catalyst is recycled and regenerated through rare earth modification, and then reused. The rare earth modification and regeneration involves adding lanthanum oxide to the recycled Raney nickel catalyst for low-temperature modification. The catalytic activity of the modified and regenerated Raney nickel catalyst can be restored to more than 95% of that of the fresh catalyst, enabling multiple reuses. This not only significantly reduces the raw material procurement cost of the catalyst but also reduces the amount of solid waste generated from spent catalysts.

Description

Technical Field

[0001] This invention relates to the field of co-production synthesis technology, specifically a process for the co-production synthesis of N,N,N'-trimethyl-N'-hydroxyethyl bisaminoethyl ether and bis(dimethylaminoethyl) ether. Background Technology

[0002] N,N,N'-trimethyl-N'-hydroxyethyl bis(aminoethyl) ether (ZF-10) and bis(dimethylaminoethyl) ether (BDMAEE) are both important organic amine chemical intermediates, widely used in polyurethane foam synthesis, pharmaceutical intermediate preparation, and water treatment agent synthesis. Market demand for both products in terms of purity and production capacity continues to increase. Currently, industrial production often employs separate synthesis processes to prepare both products, which suffers from low raw material utilization, cumbersome production processes, and high equipment investment costs. While some co-production processes have achieved simultaneous preparation of both products, they still have many technical shortcomings and cannot meet the requirements of efficient industrial production.

[0003] In existing hydroxyethylation processes, the ethylene oxide dropping rate is often controlled using a single method, which can easily lead to excessively high local concentrations, triggering ring-opening side reactions, reducing the efficiency of intermediate formation, and further affecting the subsequent methylation reaction. Moreover, the waste gas and wastewater generated during the co-production process lack targeted treatment processes. Direct discharge of organic solvents not only wastes raw materials but also leads to excessive VOCs. Direct discharge of wastewater without deep treatment will cause water pollution problems, which contradicts the current requirements of green chemical production.

[0004] In summary, developing a co-production synthesis process for ZF-10 and BDMAEE that features high raw material utilization, high product yield and purity, recyclable catalyst, and environmental protection requirements has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To address the problems in the prior art, the present invention provides a process for the co-production of N,N,N'-trimethyl-N'-hydroxyethyl bisaminoethyl ether and bis(dimethylaminoethyl) ether.

[0006] The technical solution adopted by this invention to solve its technical problem is: a co-production process for N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether and bis(dimethylaminoethyl) ether, using methylethanolamine, concentrated sulfuric acid, ethylene oxide, paraformaldehyde, and hydrogen as raw materials, and sequentially through BMAEE synthesis, hydroxyethylation reaction, methylation reaction, and distillation purification steps to achieve co-production. Raney nickel is used as a catalyst in the methylation reaction. The Raney nickel catalyst is recycled and regenerated by rare earth modification. The rare earth modification and regeneration involves adding lanthanum oxide to the recycled Raney nickel catalyst for low-temperature modification treatment.

[0007] As a further technical solution, the BMAEE synthesis process is as follows: methylethanolamine and concentrated sulfuric acid are added to an enamel-lined reactor at a mass ratio of 1:(0.9-1.1), and the reaction is carried out dropwise at a controlled temperature of 100±2℃. The temperature is then raised to 195±3℃ and the reaction is carried out for 15 hours. The mixture is then neutralized stepwise with 8%-10% sodium hydroxide solution to a pH of 7.0±0.5. After precise filtration, the mixture is subjected to vacuum distillation under conditions of -0.08MPa, 110±3℃, and a reflux ratio of 2:1 to obtain the BMAEE product.

[0008] As a further technical solution, the hydroxyethylation reaction process is as follows: BMAEE and methanol are added to a stainless steel autoclave at a volume ratio of 1:(2.2-2.8). After nitrogen purging three times, the pressure is increased to 1.0±0.05MPa, the temperature is raised to 40±2℃, and the mixture is stirred at 300r / min. Ethylene oxide is first added dropwise at a rate of 6mL / min. When the concentration of ethylene oxide in the system is ≤2.0wt%, the rate is adjusted to 8mL / min. After the addition is completed, the mixture is kept at 40±2℃ and stirred at 300r / min for 2 hours to obtain a mixed solution containing the intermediate.

[0009] As a further technical solution, the methylation reaction process is as follows: Paraformaldehyde is added to the mixed solution for dissolution, the molar ratio of paraformaldehyde to BMAEE is 1.1:1, Raney nickel catalyst accounting for 2%-3% of the mass of the mixed solution is added, nitrogen is purged three times, hydrogen is introduced, the temperature is controlled at 80±2℃, and the pressure is maintained at 1.5±0.05MPa by continuously adding hydrogen at constant pressure. The reaction is carried out at a combined rate of paddle stirring at 300-350r / min and turbine stirring at 350-400r / min for 5 hours. After the reaction is completed, the mixture is allowed to stand for 30 minutes to separate the Raney nickel catalyst.

[0010] As a further technical solution, the distillation purification process adopts a dual-tower precision distillation process. The first-stage distillation column has 28 theoretical plates, a reflux ratio of 4:1, a distillation temperature of 85±3℃, and a vacuum degree of -0.09MPa to remove low-boiling substances. The second-stage distillation column has 30 theoretical plates, a reflux ratio of 5:1, a distillation temperature of 95±3℃, and a vacuum degree of -0.085MPa, to obtain ZF-10 and BDMAEE products, respectively.

[0011] As a further technical solution, the waste gas generated during the co-production process undergoes low-temperature condensation and recovery pretreatment at -5±2℃. The organic solvent recovered from the condensation is reused in the methylation reaction process, and then subjected to three-stage activated carbon adsorption treatment. The process parameters for the three-stage activated carbon adsorption are: activated carbon loading of 50 kg per stage and waste gas space velocity of 1000 h⁻¹. -1 The adsorption temperature is 25±5℃. After treatment, the VOCs removal rate is ≥99%, and the concentration of non-methane total hydrocarbons in the waste gas is ≤50mg / m³. 3 .

[0012] As a further technical solution, the wastewater generated during the co-production process undergoes Fenton oxidation + A / O biochemical deep treatment. The process parameters for Fenton oxidation are: pH controlled at 3.0±0.2, Fe... 2+ The molar ratio of H2O2 to H2O2 is 1:4, the stirring rate is 200 r / min, the reaction time is 2 h, the dissolved oxygen in the biochemical stage is controlled at 2-3 mg / L, and part of the treated wastewater is reused in the raw material pretreatment and equipment cleaning processes.

[0013] As a further technical solution, the recycling and regeneration process of the Raney nickel catalyst is as follows: after the separated Raney nickel catalyst is washed three times with deionized water and twice with anhydrous methanol to remove impurities, it is dried at 80±5℃ for 2 hours under an inert atmosphere, and then modified by adding 0.6%-0.9% of La2O3 by mass of the Raney nickel catalyst. Then, it is calcined at 100±5℃ for 2.5 hours to complete the regeneration. During the modification and regeneration process, the nitrogen flow rate is controlled at 0.8-1.0 L / min.

[0014] As a further technical solution, the inert atmosphere is a nitrogen atmosphere.

[0015] The beneficial effects of this invention are:

[0016] 1. This invention uses Raney nickel as a catalyst in the methylation reaction and designs a targeted rare earth modification and regeneration process. La2O3 is added to the recovered Raney nickel catalyst for low-temperature modification and calcination. La2O3 can form a protective layer of active sites on the surface of the Raney nickel catalyst, repairing the active sites lost during the reaction, while simultaneously improving the hydrogenation selectivity of the catalyst and avoiding non-directional methylation side reactions. The catalytic activity of the modified and regenerated Raney nickel catalyst can be restored to more than 95% of that of the fresh catalyst, enabling multiple cycles of reuse. This not only significantly reduces the raw material procurement cost of the catalyst but also reduces the amount of solid waste generated from spent catalysts, solving the problems of high catalyst cost and difficulty in recycling in existing processes from the source.

[0017] 2. Because this invention employs a segmented control method for the ethylene oxide dropping rate in the hydroxyethylation reaction, a low-speed dropping rate is initially used to ensure the directional ring-opening reaction of ethylene oxide. The dropping rate is then increased as the ethylene oxide concentration in the system decreases, avoiding side reactions caused by excessively high local concentrations and increasing the intermediate formation efficiency to over 90%. Simultaneously, controlling the temperature, pressure, and stirring rate of the hydroxyethylation reaction provides a suitable reaction environment for the directional addition of ethylene oxide and BDMAEE, further reducing by-product formation and providing high-purity intermediate raw materials for subsequent methylation reactions. Furthermore, the dual-tower precision distillation process, by matching different theoretical plate numbers, reflux ratios, and vacuum levels, achieves complete removal of low-boiling-point substances and efficient separation of ZF-10 and BDMAEE. The first-stage distillation column specifically removes light component impurities, while the second-stage distillation column achieves fractionation of the two target products. This separation process ensures product purity, and with by-product control at each reaction step, the purity of both products is ultimately stabilized at over 95.5%. The process parameters of each step form a synergistic control effect, reducing impurity generation throughout the entire process from reaction initiation to product separation, thus solving the core problems of low product yield and substandard purity in existing processes.

[0018] 3. The co-production synthesis process of this invention achieves the directional and simultaneous preparation of ZF-10 and BDMAEE. Using methylethanolamine as a single starting material, the directional reaction path of BMAEE synthesis, hydroxyethylation, and methylation significantly improves the atom utilization rate of the raw materials. Compared with the individual synthesis process, raw material consumption is reduced by more than 25%, and production efficiency is increased by 40%. At the same time, targeted treatment processes for waste gas and wastewater are designed. The waste gas is condensed at low temperature to recover organic solvents and reused in the methylation reaction process. Then, it is subjected to three-stage activated carbon adsorption to achieve efficient removal of VOCs, which reduces raw material waste and meets environmental emission requirements. The wastewater is partially reused after Fenton oxidation + A / O biochemical deep treatment, realizing the recycling of water resources and reducing the cost of production water. From an overall process perspective, the various steps and technical features have formed a high degree of synergy. The optimization of the catalytic system ensures reaction efficiency, the control of process parameters reduces by-products, the environmental protection process realizes resource recycling, and the distillation process ensures product purity. Ultimately, a green and efficient co-production synthesis process with high raw material utilization, high product yield and purity, recyclable catalyst, and compliant emissions of waste gas, wastewater, and solid waste has been formed. This solves the problems of high raw material costs, low production efficiency, and poor environmental performance of existing processes, and significantly enhances the industrial application value of the process, which is in line with the current development trend of green, efficient, and energy-saving chemical industry. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a process for the co-production of N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether and bis(dimethylaminoethyl) ether. Using methylethanolamine, concentrated sulfuric acid, ethylene oxide, paraformaldehyde, and hydrogen as raw materials, the process involves sequential BMAEE synthesis, hydroxyethylation reaction, methylation reaction, and distillation purification steps to achieve co-production. Raney nickel is used as a catalyst in the methylation reaction. The Raney nickel catalyst is recycled and regenerated through rare earth modification. The rare earth modification and regeneration involves adding lanthanum oxide to the recycled Raney nickel catalyst for low-temperature modification.

[0021] This invention regulates the process parameters of each step in the co-production synthesis, and simultaneously completes the rare earth modification and regeneration process for catalyst recovery, as well as the environmental protection treatment process for waste gas and wastewater during the co-production process. While achieving efficient co-production of N,N,N'-trimethyl-N'-hydroxyethyl bis(dimethylaminoethyl) ether and bis(dimethylaminoethyl) ether, it also realizes the recycling of catalyst, reduces the cost of raw materials, and ensures that the production process meets environmental emission requirements, thus achieving green production.

[0022] This invention first involves a BMAEE synthesis process, using methylethanolamine and concentrated sulfuric acid as raw materials. The BMAEE product is obtained through neutralization, filtration, and vacuum distillation. In this invention, both the methylethanolamine and concentrated sulfuric acid are commercially available products well-known to those skilled in the art, without any specific model restrictions.

[0023] In this invention, the preferred BMAEE synthesis process is as follows: methylethanolamine and concentrated sulfuric acid are added to an enamel-lined reactor at a mass ratio of 1:(0.9-1.1), and the reaction is carried out dropwise at a controlled temperature of 100±2℃. The temperature is then raised to 195±3℃ and the reaction is carried out for 15 hours. The mixture is then neutralized stepwise with 8%-10% sodium hydroxide solution to a pH of 7.0±0.5. After precise filtration, the mixture is subjected to vacuum distillation at a vacuum degree of -0.08MPa, a temperature of 110±3℃, and a reflux ratio of 2:1 to obtain the BMAEE product.

[0024] After obtaining the BMAEE product, the present invention performs a hydroxyethylation reaction process, using BMAEE and ethylene oxide as raw materials and methanol as solvent, and reacting dropwise in an autoclave to obtain a mixed solution containing intermediates. In the present invention, both ethylene oxide and methanol can be commercially available products well known to those skilled in the art, without any special model restrictions; the equipment used for the reaction is a stainless steel autoclave, which is conventional chemical production reaction equipment.

[0025] In this invention, the preferred hydroxyethylation reaction step is as follows: BMAEE and methanol are added to a stainless steel autoclave at a volume ratio of 1:(2.2-2.8), purged with nitrogen three times, pressurized to 1.0±0.05MPa, heated to 40±2℃, stirred at 300r / min, and ethylene oxide is added dropwise at a rate of 6mL / min. When the concentration of ethylene oxide in the system is ≤2.0wt%, the rate is adjusted to 8mL / min. After the addition is completed, the reaction is maintained at 40±2℃ and 300r / min for 2 hours to obtain a mixed solution containing the intermediate.

[0026] After obtaining the mixed solution containing the intermediate, the present invention performs a methylation reaction step, adding paraformaldehyde and Raney nickel catalyst to the mixed solution, using hydrogen as the methylation reagent, and after catalytic hydrogenation methylation reaction, separating the Raney nickel catalyst to obtain the methylation reaction product. In the present invention, the paraformaldehyde and hydrogen are both commercially available products well known to those skilled in the art, and the purity of the hydrogen needs to meet the requirements of hydrogenation reactions in chemical production; the Raney nickel catalyst is a conventional Raney nickel catalyst for hydrogenation reactions, without any special type restrictions.

[0027] In this invention, the preferred methylation reaction step is as follows: adding paraformaldehyde to the mixed solution for dissolution, wherein the molar ratio of paraformaldehyde to BMAEE is 1.1:1, adding 2%-3% Raney nickel catalyst by mass of the mixed solution, purging with nitrogen three times, then introducing hydrogen gas, maintaining the temperature at 80±2℃ and the pressure at 1.5±0.05MPa by continuously adding hydrogen gas at constant pressure, reacting at a combined rate of paddle stirring at 300-350 r / min and turbine stirring at 350-400 r / min for 5 hours, and allowing the mixture to stand for 30 minutes after the reaction to separate the Raney nickel catalyst.

[0028] After the methylation reaction is completed, the present invention recovers and regenerates the separated Raney nickel catalyst through rare earth modification, achieving catalyst recycling. The rare earth modification and regeneration involves adding lanthanum oxide to the recovered Raney nickel catalyst for low-temperature modification. In this invention, the lanthanum oxide is preferably La2O3, and commercially available products well-known to those skilled in the art can be used.

[0029] In this invention, the preferred process for recycling and regenerating the Raney nickel catalyst is as follows: the separated Raney nickel catalyst is washed three times with deionized water and twice with anhydrous methanol to remove impurities, then dried at 80±5℃ for 2 hours under an inert atmosphere, and modified by adding 0.6%-0.9% of La2O3 by mass of the Raney nickel catalyst. Regeneration is then completed by low-temperature calcination at 100±5℃ for 2.5 hours. During the modification and regeneration process, the nitrogen flow rate is controlled at 0.8-1.0 L / min. The inert atmosphere is preferably a nitrogen atmosphere, and the nitrogen is conventional industrial nitrogen with a purity that meets the process requirements.

[0030] After the methylation reaction is completed, the methylation product is purified by distillation to obtain ZF-10 (N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether) and BDMAEE (bis(dimethylaminoethyl) ether). In this invention, the distillation purification employs a dual-tower precision distillation process. The distillation towers used are conventional precision distillation towers used in chemical production, and their parameters can be adjusted according to production requirements.

[0031] In this invention, the preferred distillation purification process is as follows: a primary distillation column with 28 theoretical plates, a reflux ratio of 4:1, a distillation temperature of 85±3℃, and a vacuum of -0.09MPa, to remove low-boiling substances; and a secondary distillation column with 30 theoretical plates, a reflux ratio of 5:1, a distillation temperature of 95±3℃, and a vacuum of -0.085MPa, to obtain ZF-10 and BDMAEE products respectively.

[0032] This invention generates industrial waste gas during the co-production synthesis process. This invention provides targeted treatment for this waste gas to achieve emission standards. In this invention, the preferred waste gas treatment process is as follows: the waste gas generated during the co-production process undergoes low-temperature condensation and recovery pretreatment at -5±2℃; the recovered organic solvent is reused in the methylation reaction process; and then it undergoes three-stage activated carbon adsorption treatment. The process parameters for the three-stage activated carbon adsorption are: activated carbon loading of 50 kg per stage and waste gas space velocity of 1000 h⁻¹. -1 The adsorption temperature is 25±5℃. After treatment, the VOCs removal rate is ≥99%, and the concentration of non-methane total hydrocarbons in the waste gas is ≤50mg / m³. 3 The activated carbon mentioned is conventional industrial waste gas treatment activated carbon, with no special model restrictions.

[0033] This invention generates industrial wastewater during the co-production process. This invention provides advanced treatment for this wastewater to achieve compliant discharge and partial reuse. In this invention, the preferred wastewater treatment process is: the wastewater generated during the co-production process undergoes Fenton oxidation + A / O biochemical advanced treatment. The process parameters for Fenton oxidation are: pH controlled at 3.0±0.2, Fe... 2+ The molar ratio of Fe to H2O2 is 1:4, the stirring rate is 200 r / min, the reaction time is 2 h, and the dissolved oxygen in the biochemical stage is controlled at 2-3 mg / L. Part of the treated wastewater is reused in the raw material pretreatment and equipment cleaning processes. The Fe used in the Fenton oxidation process... 2+ The reagents are conventional industrial ferrous salts, such as ferrous sulfate and ferrous chloride, with no special restrictions.

[0034] The co-production process for N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether and bis(dimethylaminoethyl) ether provided by this invention achieves efficient co-production of the two target products through synergistic parameter control of each step, with a total yield ≥88% and product purity ≥95.5%. Simultaneously, the rare earth modification and regeneration process of Raney nickel catalyst enables catalyst recycling, significantly reducing raw material costs and solving the problem of high single-use catalyst costs in traditional processes. Furthermore, the accompanying waste gas and wastewater treatment processes ensure that the emissions of waste gas, wastewater, and solid waste meet environmental protection requirements, achieving a green and low-cost process with promising industrial application prospects.

[0035] To further illustrate the present invention, the following detailed examples are provided. In the following examples of the present invention: the methylethanolamine, concentrated sulfuric acid, ethylene oxide, and paraformaldehyde used are all commercially available industrial-grade raw materials; the hydrogen is industrial-grade high-purity hydrogen; the Raney nickel catalyst is a commercially available Raney nickel catalyst specifically for hydrogenation reactions; La2O3 is a commercially available analytical grade reagent; sodium hydroxide, ferrous salt, hydrogen peroxide, etc., are all commercially available industrial-grade reagents; the activated carbon used is columnar activated carbon for industrial waste gas treatment, with no special model restrictions; the enamel-lined reactor, stainless steel high-pressure reactor, and double-tower precision distillation column used are all conventional chemical production equipment, and the equipment parameters only need to meet the process requirements.

[0036] Example 1:

[0037] (1) BMAEE synthesis process:

[0038] Methylethanolamine and concentrated sulfuric acid were added to an enamel-lined reactor at a mass ratio of 1:0.9. The reaction was carried out dropwise at a controlled temperature of 98°C. After the addition was complete, the temperature was raised to 192°C and the reaction was carried out for 15 hours. After the reaction was completed, the system was neutralized stepwise with a dilute sodium hydroxide solution of 8% by mass until the pH of the system was 6.5. The neutralized solution was then filtered through a precision filter and subjected to vacuum distillation under vacuum conditions of -0.08 MPa, 107°C, and a reflux ratio of 2:1 to obtain the BMAEE product.

[0039] (2) Hydroxyethylation reaction process:

[0040] BMAEE and methanol were added to a stainless steel autoclave at a volume ratio of 1:2.2. The air inside the autoclave was replaced with nitrogen three times, and the pressure was increased to 0.95 MPa after replacement. The temperature was raised to 38°C, and stirring was started at 300 r / min. Ethylene oxide was added dropwise at a rate of 6 mL / min. When the concentration of ethylene oxide in the system was not higher than 2.0 wt%, the dropping rate was adjusted to 8 mL / min. After the addition was completed, the reaction was maintained at 38°C and 300 r / min for 2 h to obtain a mixed solution containing the intermediate.

[0041] (3) Methylation reaction process:

[0042] Paraformaldehyde was added to the above mixed solution and stirred until completely dissolved. The molar ratio of paraformaldehyde to BMAEE was 1.1:1. Raney nickel catalyst, accounting for 2% of the mass of the mixed solution, was added. The air in the reactor was replaced three times with nitrogen. After the replacement, hydrogen was introduced. The temperature was controlled at 78°C, and the system pressure was maintained at 1.45 MPa by continuously adding hydrogen at constant pressure. A combination of paddle and turbine stirring was used, with the paddle stirring speed at 300 r / min and the turbine stirring speed at 350 r / min, and the reaction was carried out for 5 h. After the reaction was completed, the mixture was allowed to stand for 30 min, and the Raney nickel catalyst was separated.

[0043] (4) Catalyst recovery and rare earth modification and regeneration:

[0044] The separated Raney nickel catalyst was washed three times with deionized water and then twice with anhydrous methanol to remove impurities. It was dried at 75°C for 2 hours under a nitrogen inert atmosphere. 0.6% of the Raney nickel catalyst mass of La2O3 was added for modification treatment. The catalyst was then calcined at 95°C for 2.5 hours to complete the catalyst regeneration. The nitrogen flow rate was controlled at 0.8 L / min during the modification and regeneration process.

[0045] (5) Distillation and purification process:

[0046] A dual-tower precision distillation process was adopted: the first-stage distillation column had 28 theoretical plates, a reflux ratio of 4:1, a distillation temperature of 82℃, and a vacuum of -0.09MPa to remove low-boiling substances from the system; the second-stage distillation column had 30 theoretical plates, a reflux ratio of 5:1, a distillation temperature of 92℃, and a vacuum of -0.085MPa; ZF-10 and BDMAEE were obtained as finished products, respectively.

[0047] (6) Waste gas treatment:

[0048] The waste gas generated in the co-production process undergoes low-temperature condensation and recovery pretreatment at -7℃, and the recovered organic solvents are reused in the methylation reaction process. After condensation, the waste gas enters a three-stage activated carbon adsorption treatment, with 50 kg of activated carbon per stage and a waste gas space velocity of 1000 h⁻¹. -1 The adsorption temperature is 20℃; the treated waste gas meets emission standards.

[0049] (7) Wastewater treatment:

[0050] Wastewater generated during the co-production process is treated by Fenton oxidation combined with A / O biochemical deep treatment: the pH is controlled at 2.8, the molar ratio of ferrous ions to hydrogen peroxide is 1:4, the stirring rate is 200 r / min, and the reaction time is 2 h; the dissolved oxygen is controlled at 2 mg / L during the biochemical stage; part of the treated wastewater is reused in the raw material pretreatment and equipment cleaning processes.

[0051] Example 2:

[0052] (1) BMAEE synthesis process:

[0053] Methylethanolamine and concentrated sulfuric acid were added to an enamel-lined reactor at a mass ratio of 1:1.1. The reaction was carried out dropwise at a controlled temperature of 102°C. After the addition was complete, the temperature was raised to 198°C and the reaction was carried out for 15 hours. After the reaction was completed, the system was neutralized stepwise with a 10% sodium hydroxide solution until the pH of the system was 7.5. The neutralized solution was then filtered through a precision filter and subjected to vacuum distillation at a vacuum of -0.08 MPa, a temperature of 113°C, and a reflux ratio of 2:1 to obtain the BMAEE product.

[0054] (2) Hydroxyethylation reaction process:

[0055] BMAEE and methanol were added to a stainless steel autoclave at a volume ratio of 1:2.8. The air inside the autoclave was replaced with nitrogen three times. After replacement, the pressure was increased to 1.05 MPa. The temperature was raised to 42°C, and stirring was started at 300 r / min. Ethylene oxide was added dropwise at a rate of 6 mL / min. When the concentration of ethylene oxide in the system was not higher than 2.0 wt%, the dropping rate was adjusted to 8 mL / min. After the addition was completed, the reaction was maintained at 42°C and 300 r / min for 2 h to obtain a mixed solution containing the intermediate.

[0056] (3) Methylation reaction process:

[0057] Paraformaldehyde was added to the above mixed solution and stirred until completely dissolved. The molar ratio of paraformaldehyde to BMAEE was 1.1:1. Raney nickel catalyst, accounting for 3% of the mass of the mixed solution, was added. The air in the reactor was replaced three times with nitrogen. After the replacement, hydrogen was introduced. The temperature was controlled at 82°C, and the system pressure was maintained at 1.55 MPa by continuously adding hydrogen at constant pressure. A combination of paddle and turbine stirring was used, with the paddle stirring speed at 350 r / min and the turbine stirring speed at 400 r / min, and the reaction was carried out for 5 h. After the reaction was completed, the mixture was allowed to stand for 30 min, and the Raney nickel catalyst was separated.

[0058] (4) Catalyst recovery and rare earth modification and regeneration:

[0059] The separated Raney nickel catalyst was washed three times with deionized water and then twice with anhydrous methanol to remove impurities. It was dried at 85°C for 2 hours under a nitrogen inert atmosphere. 0.9% of the Raney nickel catalyst mass of La2O3 was added for modification treatment. The catalyst was then calcined at 105°C for 2.5 hours to complete catalyst regeneration. The nitrogen flow rate was controlled at 1.0 L / min during the modification and regeneration process.

[0060] (5) Distillation and purification process:

[0061] A dual-tower precision distillation process was adopted: the first-stage distillation column had 28 theoretical plates, a reflux ratio of 4:1, a distillation temperature of 88℃, and a vacuum of -0.09MPa to remove low-boiling substances from the system; the second-stage distillation column had 30 theoretical plates, a reflux ratio of 5:1, a distillation temperature of 98℃, and a vacuum of -0.085MPa; ZF-10 and BDMAEE were obtained as finished products, respectively.

[0062] (6) Waste gas treatment:

[0063] The waste gas generated in the co-production process undergoes low-temperature condensation and recovery pretreatment at -3℃, and the recovered organic solvents are reused in the methylation reaction process. After condensation, the waste gas enters a three-stage activated carbon adsorption treatment, with 50 kg of activated carbon per stage and a waste gas space velocity of 1000 h⁻¹. -1 The adsorption temperature is 30℃; the treated waste gas meets emission standards.

[0064] (7) Wastewater treatment:

[0065] Wastewater generated during the co-production process is treated by Fenton oxidation combined with A / O biochemical deep treatment: the pH is controlled at 3.2, the molar ratio of ferrous ions to hydrogen peroxide is 1:4, the stirring rate is 200 r / min, and the reaction time is 2 h; the dissolved oxygen is controlled at 3 mg / L during the biochemical stage; part of the treated wastewater is reused in the raw material pretreatment and equipment cleaning processes.

[0066] Example 3:

[0067] (1) BMAEE synthesis process:

[0068] Methylethanolamine and concentrated sulfuric acid were added to an enamel-lined reactor at a mass ratio of 1:1.0. The reaction was carried out dropwise at a controlled temperature of 100°C. After the addition was complete, the temperature was raised to 195°C and the reaction was carried out for 15 hours. After the reaction was completed, the system was neutralized stepwise with a 9% sodium hydroxide solution until the pH of the system was 7.0. The neutralized solution was then filtered through a precision filter and subjected to vacuum distillation under vacuum conditions of -0.08 MPa, 110°C, and a reflux ratio of 2:1 to obtain the BMAEE product.

[0069] (2) Hydroxyethylation reaction process:

[0070] BMAEE and methanol were added to a stainless steel autoclave at a volume ratio of 1:2.5. The air inside the autoclave was replaced with nitrogen three times. After replacement, the pressure was increased to 1.0 MPa. The temperature was raised to 40°C, and stirring was started at 300 r / min. Ethylene oxide was added dropwise at a rate of 6 mL / min. When the concentration of ethylene oxide in the system was not higher than 2.0 wt%, the dropping rate was adjusted to 8 mL / min. After the addition was completed, the reaction was maintained at 40°C and 300 r / min for 2 h to obtain a mixed solution containing the intermediate.

[0071] (3) Methylation reaction process:

[0072] Paraformaldehyde was added to the above mixed solution and stirred until completely dissolved. The molar ratio of paraformaldehyde to BMAEE was 1.1:1. Raney nickel catalyst, accounting for 2.5% of the mass of the mixed solution, was added. The air in the reactor was replaced three times with nitrogen. After the replacement, hydrogen was introduced. The temperature was controlled at 80°C, and the system pressure was maintained at 1.5 MPa by continuously adding hydrogen at constant pressure. A combination of paddle and turbine stirring was used, with the paddle stirring speed at 320 r / min and the turbine stirring speed at 370 r / min. The reaction was carried out for 5 h. After the reaction was completed, the mixture was allowed to stand for 30 min, and the Raney nickel catalyst was separated.

[0073] (4) Catalyst recovery and rare earth modification and regeneration:

[0074] The separated Raney nickel catalyst was washed three times with deionized water and then twice with anhydrous methanol to remove impurities. It was dried at 80°C for 2 hours under a nitrogen inert atmosphere. 0.75% by weight of La2O3 was added for modification treatment. The catalyst was then calcined at 100°C for 2.5 hours to complete the catalyst regeneration. The nitrogen flow rate was controlled at 0.9 L / min during the modification and regeneration process.

[0075] (5) Distillation and purification process:

[0076] A dual-tower precision distillation process was adopted: the first-stage distillation column had 28 theoretical plates, a reflux ratio of 4:1, a distillation temperature of 85℃, and a vacuum of -0.09MPa to remove low-boiling substances from the system; the second-stage distillation column had 30 theoretical plates, a reflux ratio of 5:1, a distillation temperature of 95℃, and a vacuum of -0.085MPa; ZF-10 and BDMAEE were obtained as finished products, respectively.

[0077] (6) Waste gas treatment:

[0078] The waste gas generated during the co-production process undergoes low-temperature condensation and recovery pretreatment at -5℃, and the recovered organic solvents are reused in the methylation reaction process. After condensation, the waste gas enters a three-stage activated carbon adsorption treatment, with 50 kg of activated carbon per stage and a waste gas space velocity of 1000 h⁻¹. -1 The adsorption temperature is 25℃; the treated exhaust gas meets emission standards.

[0079] (7) Wastewater treatment:

[0080] Wastewater generated during the co-production process is treated by Fenton oxidation combined with A / O biochemical deep treatment: the pH is controlled at 3.0, the molar ratio of ferrous ions to hydrogen peroxide is 1:4, the stirring rate is 200 r / min, and the reaction time is 2 h; the dissolved oxygen is controlled at 2.5 mg / L during the biochemical stage; part of the treated wastewater is reused in the raw material pretreatment and equipment cleaning processes.

[0081] Comparative Example 1:

[0082] Compared with Example 3, the difference is that Raney nickel catalyst is not used in the methylation reaction, and the hydrogenation methylation reaction is carried out directly, while the rest of the process is exactly the same.

[0083] Comparative Example 2:

[0084] Compared with Example 3, the difference is that the Raney nickel catalyst is only recycled and washed, without undergoing La2O3 rare earth modification and regeneration, and is directly recycled to the methylation reaction, while the rest of the process is exactly the same.

[0085] Comparative Example 3:

[0086] Compared with Example 3, the difference is that ethylene oxide is added at a single rate of 6 mL / min throughout the hydroxyethylation reaction without segmented addition adjustments, while the rest of the process is exactly the same.

[0087] Comparative Example 4:

[0088] Compared with Example 3, the difference is that the methylation reaction only uses a single paddle stirrer at 300 r / min, without using a paddle + turbine combined stirrer, while the rest of the process is exactly the same.

[0089] test:

[0090] Experiment 1: Overall Product Yield Test

[0091] Test method:

[0092] 1) Collect ZF-10 (N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether) and BDMAEE (bis(dimethylaminoethyl) ether) products obtained after distillation in Examples 1-3 and Comparative Examples 1-4 respectively;

[0093] 2) The actual yield of each product is calculated by weighing. Based on the theoretical yield of BMAEE, the yields of ZF-10 and BDMAEE are calculated separately, and the sum of the two is the total yield.

[0094] 3) Each group of samples was tested in parallel 3 times, and the average value was taken as the final result.

[0095] Experimental data:

[0096] Table 1

[0097] sample Total yield / % Example 1 88.2 Example 2 88.5 Example 3 89.1 Comparative Example 1 62.3 Comparative Example 2 75.6 Comparative Example 3 80.5 Comparative Example 4 82.7

[0098] As shown in Table 1, the overall yield of Examples 1-3 was ≥88%. In Comparative Example 1, no Raney nickel catalyst was used, making the methylation reaction difficult to proceed, resulting in extremely low conversion of the target product and a significant decrease in overall yield. In Comparative Example 2, the catalyst was not modified or regenerated, leading to a reduction in active sites and catalytic efficiency, resulting in a significantly lower overall yield than the Examples. In Comparative Example 3, the addition of ethylene oxide was improper, resulting in excessively high local concentrations and side reactions, which reduced the yield of intermediates and ultimately lowered the overall yield. In Comparative Example 4, the stirring method was simplistic, the system was unevenly mixed, the contact between hydrogen and the raw materials was insufficient, the reaction was incomplete, and the overall yield was low.

[0099] Experiment 2: Product Purity Test

[0100] Test method:

[0101] ZF-10 and BDMAEE products from Examples 1-3 and Comparative Examples 1-4 were taken respectively. Purity was determined by gas chromatography using a polar capillary column, a programmed temperature ramp mode, and an FID detector. Product purity was calculated using the area normalization method. Each sample was tested in parallel three times, and the average value was taken.

[0102] 2. Experimental data:

[0103] Table 2

[0104] sample ZF-10 purity / % BDMAEE purity / % Example 1 95.7 95.6 Example 2 95.9 95.8 Example 3 96.2 96.0 Comparative Example 1 82.1 81.8 Comparative Example 2 88.3 88.0 Comparative Example 3 92.4 92.1 Comparative Example 4 93.6 93.3

[0105] In Examples 1-3, the purity of ZF-10 and BDMAEE was ≥95.5%. In Comparative Example 1, no catalyst was used, resulting in the formation of a large amount of byproducts, and the purity of both products was much lower than that of the Examples. In Comparative Example 2, the catalyst was deactivated, the selectivity decreased, the impurity content increased, and the purity was significantly reduced. In Comparative Example 3, the dropping method was improper, resulting in the formation of structurally similar impurities that were difficult to completely remove by distillation, and the purity did not meet the standards. In Comparative Example 4, the mixing effect was poor, with local over-reaction or incomplete reaction, resulting in increased impurities and the product purity was lower than that of the Examples.

[0106] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the co-production of N,N,N'-trimethyl-N'-hydroxyethyl bisaminoethyl ether and bis(dimethylaminoethyl) ether, characterized in that, Using methylethanolamine, concentrated sulfuric acid, ethylene oxide, paraformaldehyde, and hydrogen as raw materials, the process involves sequential BMAEE synthesis, hydroxyethylation reaction, methylation reaction, and distillation purification to achieve co-production. Raney nickel is used as a catalyst in the methylation reaction. The Raney nickel catalyst is recycled and regenerated by rare earth modification. The rare earth modification and regeneration involves adding lanthanum oxide to the recycled Raney nickel catalyst for low-temperature modification treatment.

2. The co-production synthesis process according to claim 1, characterized in that, The BMAEE synthesis process is as follows: methylethanolamine and concentrated sulfuric acid are added to an enamel-lined reactor at a mass ratio of 1:(0.9-1.1), and the reaction is carried out dropwise at a controlled temperature of 100±2℃. The temperature is then raised to 195±3℃ and the reaction is carried out for 15 hours. The mixture is then neutralized stepwise with 8%-10% sodium hydroxide solution to a pH of 7.0±0.

5. After precise filtration, the mixture is subjected to vacuum distillation at a vacuum degree of -0.08MPa, a temperature of 110±3℃, and a reflux ratio of 2:1 to obtain the BMAEE product.

3. The co-production synthesis process according to claim 2, characterized in that, The hydroxyethylation reaction process is as follows: BMAEE and methanol are added to a stainless steel autoclave at a volume ratio of 1:(2.2-2.8). After nitrogen purging three times, the pressure is increased to 1.0±0.05MPa, the temperature is raised to 40±2℃, and the mixture is stirred at 300r / min. Ethylene oxide is first added dropwise at a rate of 6mL / min. When the concentration of ethylene oxide in the system is ≤2.0wt%, the rate is adjusted to 8mL / min. After the addition is completed, the mixture is kept at 40±2℃ and stirred at 300r / min for 2 hours to obtain a mixed solution containing the intermediate.

4. The co-production synthesis process according to claim 3, characterized in that, The methylation reaction process is as follows: Paraformaldehyde is added to the mixed solution to dissolve it, with a molar ratio of paraformaldehyde to BMAEE of 1.1:

1. Raney nickel catalyst, accounting for 2%-3% of the mass of the mixed solution, is added. After nitrogen purging three times, hydrogen is introduced. The temperature is controlled at 80±2℃, and the pressure is maintained at 1.5±0.05MPa by continuously adding hydrogen at constant pressure. The reaction is carried out at a combined rate of paddle stirring at 300-350r / min and turbine stirring at 350-400r / min for 5 hours. After the reaction is completed, the mixture is allowed to stand for 30 minutes to separate the Raney nickel catalyst.

5. The co-production synthesis process according to claim 1, characterized in that, The distillation and purification process employs a dual-tower precision distillation process. The first-stage distillation column has 28 theoretical plates, a reflux ratio of 4:1, a distillation temperature of 85±3℃, and a vacuum of -0.09MPa to remove low-boiling substances. The second-stage distillation column has 30 theoretical plates, a reflux ratio of 5:1, a distillation temperature of 95±3℃, and a vacuum of -0.085MPa, yielding ZF-10 and BDMAEE products, respectively.

6. The co-production synthesis process according to claim 1, characterized in that, The waste gas generated during the co-production process undergoes low-temperature condensation and recovery pretreatment at -5±2℃. The organic solvent recovered from the condensation is reused in the methylation reaction process. The waste gas then undergoes three-stage activated carbon adsorption treatment. The process parameters for the three-stage activated carbon adsorption are: activated carbon loading of 50 kg per stage and waste gas space velocity of 1000 h⁻¹. -1 The adsorption temperature is 25±5℃. After treatment, the VOCs removal rate is ≥99%, and the concentration of non-methane total hydrocarbons in the waste gas is ≤50mg / m³. 3 .

7. The co-production synthesis process according to claim 1, characterized in that, Wastewater generated during the co-production process undergoes Fenton oxidation + A / O biochemical deep treatment. The process parameters for Fenton oxidation are: pH controlled at 3.0±0.2, Fe... 2+ The molar ratio of H2O2 to H2O2 is 1:4, the stirring rate is 200 r / min, the reaction time is 2 h, the dissolved oxygen in the biochemical stage is controlled at 2-3 mg / L, and part of the treated wastewater is reused in the raw material pretreatment and equipment cleaning processes.

8. The co-production synthesis process according to claim 1, characterized in that, The recycling and regeneration process of the Raney nickel catalyst is as follows: after the separated Raney nickel catalyst is washed three times with deionized water and twice with anhydrous methanol to remove impurities, it is dried at 80±5℃ for 2 hours under an inert atmosphere, and then modified by adding 0.6%-0.9% of La2O3 by mass of the Raney nickel catalyst. Then, it is calcined at 100±5℃ for 2.5 hours to complete the regeneration. During the modification and regeneration process, the nitrogen flow rate is controlled at 0.8-1.0 L / min.

9. The co-production synthesis process according to claim 8, characterized in that, The inert atmosphere is a nitrogen atmosphere.