Efficient and environment-friendly production method of diethanolisopropanolamine

Abstract

The invention discloses a high-efficiency and environment-friendly production method of diethanolisopropanolamine, diethanol amine and epoxypropane are used as raw materials and react under the action of a composite catalyst, and the composite catalyst is composed of 1, 8-diazabicyclo undec-7-ene (DBU) and cobalt acetate. The adopted composite catalyst system is a composite catalyst, and the reaction is catalyzed from different angles through the synergistic effect of the organic base and the transition metal salt. DBU promotes ring opening of epoxypropane, cobalt acetate activates reactants and stabilizes reaction intermediates, and side reactions such as a polymerization reaction of diethanol amine and epoxypropane are effectively inhibited, so that the purity and yield of the product are improved.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and in particular to a method for producing diethanol monoisopropanolamine which is efficient and environmentally friendly. Background Art

[0002] Diethanolmonoisopropanolamine (DEIPA) is an important multifunctional amine compound widely used in surfactants, cement grinding aids, gas desulfurizers, pharmaceutical intermediates, and polymer material modification. Its molecular structure contains both hydroxyl and amino functional groups, endowing it with excellent chelating, emulsifying, and corrosion-inhibiting properties. Its application in green building materials and environmentally friendly industrial additives is growing, especially in demand. Traditional methods for producing DEIPA primarily include high-temperature and high-pressure methods and catalytic methods.

[0003] The high-temperature, high-pressure method, typically conducted at 180-220°C and 2-5 MPa, involves a direct reaction of diethanolamine and propylene oxide in the absence of a catalyst. This method requires significant equipment investment and high energy consumption. Furthermore, the harsh reaction conditions can easily lead to self-polymerization and side reactions of propylene oxide, resulting in low product selectivity and purity. Complex post-processing is often required for purification, increasing production costs. Furthermore, high-temperature, high-pressure conditions place high demands on equipment materials and safety, posing potential safety risks.

[0004] The catalytic method involves conducting the reaction under relatively mild conditions in the presence of a catalyst. Commonly used catalysts include inorganic bases (such as sodium hydroxide and potassium hydroxide), Lewis acids (such as aluminum chloride and ferric chloride), and some organic catalysts. While these catalysts can reduce reaction temperature and pressure to a certain extent and increase reaction rate, they still suffer from the following issues: insufficient catalytic activity and prolonged reaction times; unsatisfactory catalytic selectivity, which can easily produce secondary addition products such as diethanoldiisopropanolamine; difficulty in catalyst recovery, which increases the environmental burden; and low reaction equipment utilization, making them unsuitable for continuous large-scale production.

[0005] In addition, the existing production process of diethanol monoisopropanolamine mostly uses intermittent reactors for reaction. This reaction method has disadvantages such as low heat transfer efficiency, uneven reaction, and large fluctuations in product quality between batches. It is difficult to meet the requirements of modern industry for product quality stability and production efficiency.

[0006] With the growing popularity of green chemistry and sustainable development, developing an efficient, environmentally friendly, and economical method for producing diethanol monoisopropanolamine has become a hot topic and a challenge. In particular, achieving highly selective reactions under mild conditions, improving the efficiency of reaction equipment, and reducing energy consumption and environmental impact during the production process are all pressing challenges. Summary of the Invention

[0007] Based on the problems existing in the background technology, the present invention provides a method for producing diethanol monoisopropanolamine that is efficient, environmentally friendly, has high product quality and is relatively low in cost. The method can use an external circulation reactor or a microchannel reactor to meet the needs of industrial large-scale production, while improving the purity and yield of the product and reducing production costs and environmental impact.

[0008] The present invention is implemented through the following technical solutions:

[0009] The invention discloses a highly efficient and environmentally friendly method for producing diethanol monoisopropanolamine. The method adopts diethanolamine and propylene oxide as raw materials and carries out a reaction under the action of a composite catalyst. The composite catalyst consists of 1,8-diazabicycloundec-7-ene and cobalt acetate.

[0010] The present invention uses diethanolamine and propylene oxide as the main raw materials. The purity of diethanolamine and propylene oxide has a significant impact on the reaction and product quality. The purity of diethanolamine must meet industrial grade standards and be no less than 99%. It has stable chemical properties and contains two hydroxyl groups and one amino group in its molecule, which has strong nucleophilicity and is capable of reacting with propylene oxide. The purity of propylene oxide is no less than 99.5%. It is a highly reactive epoxy compound, and the epoxy bonds in its molecules readily undergo ring-opening reactions under the action of a catalyst. Selecting high-purity raw materials can reduce the interference of impurities in the reaction, improve the selectivity of the reaction, and improve the purity of the product.

[0011] Furthermore, the molar ratio of diethanolamine to propylene oxide is 1:(0.9-1.1).

[0012] Furthermore, the mass ratio of the 1,8-diazabicycloundec-7-ene (DBU) to cobalt acetate is (3-5):1.

[0013] Function of DBU: DBU has strong alkalinity and moderate steric hindrance. Its strong alkalinity promotes the ring-opening reaction of propylene oxide, making the epoxy bond of propylene oxide more susceptible to attack by nucleophiles. Moderate steric hindrance prevents overreaction and improves reaction selectivity. DBU can form specific hydrogen bonds or ion pairs with reactants, changing the electron cloud distribution of the reactants, thereby reducing the activation energy of the reaction and accelerating the reaction rate.

[0014] Function of Cobalt Acetate: Cobalt acetate can form specific complexes with reactants. During the reaction, the metal ions of cobalt acetate form coordination bonds with the oxygen atoms of propylene oxide or the nitrogen atoms of diethanolamine, causing a certain degree of deformation of the reactant molecules, reducing the activation energy of the reaction and improving the selectivity and rate of the reaction. Cobalt acetate also stabilizes the reaction intermediates and reduces the occurrence of side reactions.

[0015] The mass ratio of DBU to cobalt acetate in the composite catalyst is (3-5):1. Within this ratio, DBU and cobalt acetate can achieve optimal synergy, improving reaction performance. If the DBU ratio is too high, the reaction may be too intense, increasing the occurrence of side reactions; if the cobalt acetate ratio is too high, it may affect the dispersion and activity of the catalyst, reducing reaction efficiency.

[0016] Furthermore, the usage of the composite catalyst is 0.3%-1.5% of the mass of diethanolamine.

[0017] The reaction principle of the present invention is as follows:

[0018] The chemical reaction equation is:

[0019] Under the action of the composite catalyst, the reaction proceeds as follows: First, DBU, acting as an organic base, performs a nucleophilic attack on the epoxy bond of propylene oxide, polarizing the bond and reducing its stability. Simultaneously, cobalt acetate forms a complex with the reactants, further activating the epoxy bond of propylene oxide. Then, the amino group of diethanolamine performs a nucleophilic attack on the ring-opened propylene oxide, forming diethanol monoisopropanolamine. The entire reaction process adheres to chemical principles and the law of conservation of matter, and the type and number of atoms remain unchanged before and after the reaction.

[0020] Furthermore, the reaction process of the present invention is carried out in an external circulation reactor or a microchannel reactor.

[0021] Furthermore, the reaction is carried out in an external circulation reactor, and the specific operations are as follows:

[0022] Adding raw materials and catalysts: Add diethanolamine to the external circulation reactor and add the composite catalyst; the amount of composite catalyst is 0.5%-1.5% of the mass of diethanolamine. Start the circulation pump to circulate the materials in the external circulation pipeline, and control the circulation flow rate at 1-3m 3 / h; Circulating flow promotes full dispersion of the catalyst in diethanolamine, ensuring full contact between the catalyst and reactants and improving reaction efficiency. An appropriate circulation flow rate ensures uniform mixing of the materials. If the flow rate is too fast, it may lead to increased energy consumption and equipment wear; if the flow rate is too slow, the catalyst may agglomerate, affecting the catalytic effect.

[0023] Propylene oxide addition: Propylene oxide is continuously added to the external circulation pipeline via a feed pump. The reaction temperature is controlled at 50-70°C and the reaction pressure is atmospheric pressure. The reaction temperature can be precisely controlled by installing a heat exchanger in the external circulation pipeline. A temperature sensor monitors the temperature in real time and provides feedback to adjust the heat exchanger's operation. The propylene oxide addition rate is adjusted based on the reaction temperature and circulation flow rate to maintain a stable reaction temperature. Slow and continuous addition of propylene oxide can avoid excessive reaction and prevent local overheating that can lead to side reactions.

[0024] Reaction Progress: The materials react continuously during the circulation process, with the reaction time controlled according to the reaction progress and product quality requirements, and the reaction time is 1-2 hours. During the reaction, samples are regularly taken from the sampling port to analyze the composition of the reaction liquid and monitor the progress of the reaction. The external circulation method continuously updates the contact interface of the reactants, improving mass and heat transfer efficiency and ensuring a more complete reaction.

[0025] Furthermore, the reaction is carried out in a microchannel reactor, and the specific operations are as follows:

[0026] Solution preparation: diethanolamine and composite catalyst are prepared into a uniform mixed solution; the amount of composite catalyst used is 0.3%-1.0% of the mass of diethanolamine; the uniform solution can ensure that the catalyst is evenly dispersed in the reactants, thereby improving the stability and selectivity of the reaction.

[0027] Material Injection: Metering pumps are used to inject the diethanolamine mixed solution and propylene oxide into the microchannel reactor. The diethanolamine mixed solution has a flow rate of 1-3 mL / min, and the propylene oxide flow rate is adjusted based on the molar ratio of diethanolamine to propylene oxide (1:0.9-1.1). Metering pumps precisely control the flow rate, ensuring an accurate ratio of reactants, thereby improving reaction selectivity and yield.

[0028] Reaction Condition Control: The reaction temperature within the microchannel reactor is maintained at 60-80°C, the reaction pressure at 0.2-0.5 MPa, and the residence time of the materials in the microchannels at 2-5 minutes. Microchannel reactors offer excellent heat and mass transfer performance, enabling thorough mixing and reaction of reactants in a short period of time. Within this temperature, pressure, and residence time range, the reaction proceeds efficiently and produces stable product quality. However, excessively high reaction temperatures or pressures can lead to equipment damage and increased side reactions; excessively short residence times can result in incomplete reactions; and excessively long residence times can increase production costs.

[0029] Beneficial effects of the present invention:

[0030] The composite catalyst system adopted by the present invention is a composite catalyst. The synergistic effect of DBU and cobalt acetate significantly improves the selectivity and rate of the reaction. Compared with traditional single catalysts, the composite catalyst can promote the reaction under milder reaction conditions. Single catalysts often can only play a role in a certain aspect, while the composite catalyst of the present invention catalyzes the reaction from different angles through the synergistic effect of organic base and transition metal salt. DBU promotes the ring-opening of propylene oxide, and cobalt acetate activates the reactants and stabilizes the reaction intermediates, effectively suppressing the generation of side reactions, such as the polymerization reaction of diethanolamine and propylene oxide, thereby improving the purity and yield of the product. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0032] Example 1

[0033] A highly efficient and environmentally friendly method for producing diethanol monoisopropanolamine is described. This embodiment is carried out in an external circulation reactor. The specific steps are as follows:

[0034] In 5m 3 Add 2000kg (19.05kmol) of diethanolamine to the external circulation reactor, and then add 20kg of composite catalyst (including 15kg of DBU and 5kg of cobalt acetate). Start the circulation pump and adjust the circulation flow rate to 2m 3 / h, so that the catalyst is fully dispersed in diethanolamine. 1051kg (18.10kmol) of propylene oxide is continuously added to the external circulation pipeline through a feed pump, and the reaction temperature is controlled to 60°C and the reaction pressure is normal pressure. The addition time of propylene oxide is 1 hour, and the temperature is kept stable by adjusting the heat exchanger during the addition process. After the material circulation reaction for 1.5 hours, samples are taken from the sampling port for analysis, and the reaction is basically completed. After the reaction is completed, the reaction liquid is subjected to reduced pressure distillation to collect the target product diethanol monoisopropanolamine. Gas chromatography analysis shows that the product purity is 99.4% and the yield is 98.7%.

[0035] Example 2

[0036] A highly efficient and environmentally friendly method for producing diethanol monoisopropanolamine is described. This embodiment is carried out in a microchannel reactor, and the specific steps are as follows:

[0037] 100g of diethanolamine and 0.6g of composite catalyst (wherein DBU 0.45g, cobalt acetate 0.15g) are mixed into a uniform solution. Diethanolamine solution is injected into a microchannel reactor at a flow rate of 2mL / min and 55.0g of propylene oxide at a flow rate of 0.8mL / min using a metering pump. The reaction temperature is controlled to be 70°C, the reaction pressure is 0.3MPa, and the residence time of the material in the microchannel is 3 minutes. During the reaction, the reaction temperature and pressure are monitored in real time by a temperature sensor and a pressure sensor to ensure that the reaction conditions are stable. After separation and purification, the reaction product obtains 152g of diethanol monoisopropanolamine. After testing, the product purity is 99.0%, and the yield is 97.0%.

[0038] Comparative Example 1

[0039] A method for producing diethanol monoisopropanolamine. This comparative example is carried out in an external circulation reactor. Based on Example 1, the weight ratio of the composite catalyst is adjusted and the amount of DBU is increased. The specific operating steps are as follows:

[0040] In 5m 3 Add 2000kg (19.05kmol) of diethanolamine and 20kg of composite catalyst (including 17kg of DBU and 3kg of cobalt acetate, with a mass ratio of about 5.67:1) to the external circulation reactor. Start the circulation pump with a circulation flow rate of 2m 3 / h. During the addition of 1051 kg (18.10 kmol) of propylene oxide, the reaction temperature rose rapidly. Even with regulation by a heat exchanger, it was difficult to maintain a stable temperature of 60°C, resulting in a relatively vigorous reaction. The reaction was concluded after 1.5 hours, and the product was obtained by vacuum distillation. Gas chromatography analysis showed a purity of 96.2% and a yield of 93.5%. A significant increase in by-products was observed, presumably due to an excessively high DBU ratio, which resulted in an overreaction of propylene oxide and the formation of a large number of polymerized by-products.

[0041] Comparative Example 2

[0042] A method for producing diethanol monoisopropanolamine. This comparative example is carried out in an external circulation reactor. Based on Example 1, the weight ratio of the composite catalyst is adjusted and the amount of cobalt acetate is increased. The specific operating steps are as follows:

[0043] In 5m 3 Add 2000kg (19.05kmol) of diethanolamine and 20kg of composite catalyst (including 12kg of DBU and 8kg of cobalt acetate, with a mass ratio of 1.5:1) to the external circulation reactor. Start the circulation pump and the circulation flow rate is 2m 3 / h. During the reaction, the catalyst was found to be agglomerated and had poor dispersibility. After adding 1051kg (18.10kmol) of propylene oxide, the reaction rate was significantly slower. After 2 hours of reaction, analysis from the sampling port showed that the reaction was still not complete. After the reaction was completed, vacuum distillation was performed to obtain the product. Gas chromatography analysis showed that the product purity was 97.1% and the yield was 94.2%. This is because the excessive proportion of cobalt acetate affects the dispersibility and activity of the catalyst, reducing the reaction efficiency.

[0044] Comparative Example 3

[0045] A method for producing diethanol monoisopropanolamine is carried out in an external circulation reactor. Based on Example 1, a single catalyst DBU is used. The specific operating steps are as follows:

[0046] In 5m 3 Add 2000kg (19.05kmol) of diethanolamine and 20kg of DBU as a single catalyst to the external circulation reactor. Start the circulation pump with a circulation flow rate of 2m 3 / h. 1051 kg (18.10 kmol) of propylene oxide was added via a feed pump, and the reaction temperature was controlled at 60°C. During the reaction, the reaction rate was relatively fast, but the selectivity was poor, side reactions were frequent, and a large amount of viscous material appeared in the reaction system. The reaction was terminated after 1.5 hours, and vacuum distillation was performed. Gas chromatography analysis showed a product purity of 93.5% and a yield of 90.2%. This is because, although DBU alone can promote the ring opening of propylene oxide, it cannot effectively inhibit the occurrence of side reactions.

[0047] Comparative Example 4

[0048] A method for producing diethanol monoisopropanolamine is carried out in an external circulation reactor. Based on Example 1, a single catalyst, cobalt acetate, is used. The specific operating steps are as follows:

[0049] In 5m 3 Add 2000kg (19.05kmol) of diethanolamine and 20kg of cobalt acetate as a single catalyst to the external circulation reactor. Start the circulation pump with a circulation flow rate of 2m 3 / h. After adding 1051 kg (18.10 kmol) of propylene oxide, the reaction rate was very slow. After 2.5 hours of reaction, a large amount of unreacted raw material was still found through sampling. After the reaction was completed, the product was distilled under reduced pressure. Gas chromatography analysis showed a purity of 95.1% and a yield of 88.3%. This indicates that the catalytic activity of cobalt acetate alone is insufficient and cannot effectively promote the reaction.

[0050] Comparative Example 5

[0051] A method for producing diethanol monoisopropanolamine. This comparative example is carried out in a microchannel reactor. Based on Example 2, the weight ratio of the composite catalyst is adjusted and the amount of DBU is increased. The specific operating steps are as follows:

[0052] 100g diethanolamine and 0.6g composite catalyst (wherein DBU 0.53g, cobalt acetate 0.07g, mass ratio is 7.6: 1) are mixed into solution. According to above-mentioned identical flow velocity and reaction conditions, react, in reaction process, temperature fluctuation is larger in microchannel, and overheating phenomenon occurs locally. After reaction terminates, product is separated and purified, and diethanol monoisopropanolamine 150.7g is obtained. After testing, product purity is 95.8%, and yield is 93.1%. Because the DBU ratio is too high, reaction is violent, and side reaction increases, causing product purity and yield to decline.

[0053] Comparative Example 6

[0054] A method for producing diethanol monoisopropanolamine. This comparative example is carried out in a microchannel reactor. Based on Example 2, the weight ratio of the composite catalyst is adjusted and the amount of cobalt acetate is increased. The specific operating steps are as follows:

[0055] 100g of diethanolamine and 0.6g of composite catalyst (wherein DBU 0.2g, cobalt acetate 0.4g, mass ratio is 0.5: 1) are formulated into a solution. Injected into a microchannel reactor with the same flow rate, it was found that the reaction rate was significantly lower than normal during the reaction. The residence time of the material in the microchannel was extended to 5 minutes, and separation and purification were carried out after the reaction was completed to obtain 150.7g of diethanol monoisopropanolamine. After testing, the product purity was 96.5%, and the yield was 93.8%. This shows that the excessively high ratio of cobalt acetate affects the catalyst activity, reduces the reaction efficiency, and causes a certain impact on the purity and yield of the product.

[0056] Comparative Example 7

[0057] A method for producing diethanol monoisopropanolamine is carried out in a microchannel reactor. Based on Example 2, a single catalyst DBU is used. The specific operating steps are as follows:

[0058] 100g of diethanolamine and 0.6g of DBU were prepared into a solution as a single catalyst. The diethanolamine solution was injected into the microchannel reactor at a flow rate of 2mL / min and propylene oxide at a flow rate of 0.8mL / min using a metering pump. The reaction temperature was controlled at 70°C, the reaction pressure was 0.3MPa, and the residence time of the material in the microchannel was 3 minutes. During the reaction, the reaction rate was fast, but the reaction selectivity was poor, and a large number of by-products appeared. After the reaction was completed, separation and purification were carried out to obtain 151.2g of diethanol monoisopropanolamine. After testing, the product purity was 92.0% and the yield was 89.7%. Although single DBU can quickly promote the ring opening of propylene oxide, it is difficult to suppress side reactions, resulting in unsatisfactory product quality and yield.

[0059] Comparative Example 8

[0060] A method for producing diethanol monoisopropanolamine is carried out in a microchannel reactor. Based on Example 2, a single catalyst, cobalt acetate, is used. The specific operating steps are as follows:

[0061] 100g of diethanolamine and 0.6g of cobalt acetate were prepared as a single catalyst solution. The reaction was carried out under the same flow rate and reaction conditions, and the reaction rate was extremely slow. The residence time of the material in the microchannel was extended to 6 minutes, and separation and purification were carried out after the reaction to obtain 144g of diethanol monoisopropanolamine. After testing, the product purity was 94.0% and the yield was 87.4%. This reflects that the single cobalt acetate catalytic activity is poor, and it cannot effectively promote the reaction, which makes the reaction process slow and the product yield is low.

[0062] Finally, it should be noted that the above-described embodiments merely represent several implementation methods of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made by a person skilled in the art without departing from the spirit of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention should be based on the appended claims.

Claims

1. A method for producing an efficient and environmentally friendly diethanol monoisopropanolamine, characterized in that: Diethanolamine and propylene oxide are used as raw materials and reacted under the action of a composite catalyst. The composite catalyst consists of 1,8-diazabicycloundec-7-ene and cobalt acetate.

2. The production method according to claim 1, characterized in that The purity of the diethanolamine is not less than 99%, and the purity of the propylene oxide is not less than 99.5%.

3. The production method according to claim 1, characterized in that The molar ratio of the diethanolamine to the propylene oxide is 1:(0.9-1.1).

4. The production method according to claim 1, characterized in that The mass ratio of the 1,8-diazabicycloundec-7-ene to cobalt acetate is (3-5):

1.

5. The production method according to claim 1, characterized in that The usage of the composite catalyst is 0.3%-1.5% of the mass of the diethanolamine.

6. The production method according to claim 1, characterized in that The reaction is carried out in an external circulation reactor or a microchannel reactor.

7. The production method according to claim 6, characterized in that The reaction is carried out in an external circulation reactor, and the specific operation is as follows: adding diethanolamine into the external circulation reactor and adding a composite catalyst; Start the circulation pump to circulate the material in the external circulation pipeline, and control the circulation flow rate at 1-3m 3 / h; Propylene oxide is continuously added to the external circulation pipeline through a feed pump; The reaction temperature is controlled at 50-70°C, the reaction pressure is normal pressure, and the reaction time is 1-2 hours.

8. The production method according to claim 7, characterized in that The usage of the composite catalyst is 0.5%-1.5% of the mass of the diethanolamine.

9. The production method according to claim 6, characterized in that The reaction is carried out in a microchannel reactor, and the specific operation is as follows: diethanolamine and the composite catalyst are prepared into a uniform mixed solution; The diethanolamine mixed solution and propylene oxide are respectively injected into the microchannel reactor by using metering pumps; The reaction temperature in the microchannel reactor is controlled at 60-80° C., the reaction pressure is controlled at 0.2-0.5 MPa, and the residence time of the material in the microchannel is controlled at 2-5 minutes.

10. The production method according to claim 9, characterized in that The amount of the composite catalyst is 0.3%-1.0% of the mass of diethanolamine; The flow rate of the diethanolamine mixed solution is 1-3 mL / min, and the flow rate of propylene oxide is adjusted according to the molar ratio of diethanolamine to propylene oxide.