A preparation method of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

Abstract

The invention discloses a method for preparing N,N,N-trimethylhydroxyethylethylenediamine, which is characterized by comprising the following steps: synthesis: using primary alcohol substances and secondary amine substances with -OH as raw materials, and reacting in a hydrogen environment to prepare the N,N,N-trimethylhydroxyethylethylenediamine; compared with the prior art, the invention uses primary alcohol substances and secondary amine substances with -OH as raw materials, and reacts in a hydrogen environment to prepare the N,N,N-trimethylhydroxyethylethylenediamine, and does not introduce formaldehyde, thereby greatly reducing the toxicity of the reaction environment, and at the same time, the product does not carry formaldehyde, making it more environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of organic compound synthesis, and in particular to a method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine. Background Art

[0002] N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine (TMAEEA for short), with the structural formula shown in S-1, is an important organic chemical intermediate and a general-purpose foaming catalyst for the synthesis of polyurethane foams, suitable for various polyurethane foam applications.

[0003] (S-1)

[0004] Among them, the patent document with application number CN201710010680.9 discloses a method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine, comprising the following steps:

[0005] 1) Synthesis:

[0006] Add hydroxyethylethylenediamine and paraformaldehyde into a container, and add formic acid dropwise under stirring, the molar ratio of hydroxyethylethylenediamine: paraformaldehyde: formic acid is 1:3-3.3:3-3.3, the reaction temperature is 50-110°C, and the reaction time is 1-2 hours; after the reaction is completed, evaporate the water generated by the reaction under reduced pressure to obtain a reaction liquid;

[0007] 2) Transesterification:

[0008] Adding an alcohol substance to the reaction solution obtained in step 1) to carry out an ester exchange reaction to obtain a reaction solution after impurities are removed;

[0009] The ratio of the alcohol substance to the hydroxyethylethylenediamine in step 1) is: 80-120 g of alcohol substance / 1.0 mol of hydroxyethylethylenediamine; the transesterification reaction is carried out at reflux temperature for 3-5 hours;

[0010] The alcohol substance is methanol, ethanol, isopropanol, and n-butanol;

[0011] 3) Distillation:

[0012] The reaction solution obtained in step 2) is subjected to reduced pressure distillation to separate alcohol substances and N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine, and the alcohol substances are recovered for reuse.

[0013] In the method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine, hydroxyethylethylenediamine, paraformaldehyde and formic acid are used as raw materials to react and prepare N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine.

[0014] At the same time, the patent application document with application number CN202110542511.6 discloses a method for using a single-atom palladium / graphene catalyst to produce N,N,N'-trimethyl-N'-hydroxyethylethylenediamine, wherein single-atom palladium / graphene is used as a catalyst, and the metal palladium in the single-atom palladium / graphene catalyst is loaded on a graphene carrier in the form of a single atom, and the single-atom palladium on the surface of the graphene is a reaction active site. The raw material hydroxyethylethylenediamine and the raw material solid polyformaldehyde are added to a reactor, heated to 110°C under a hydrogen atmosphere, the reactor pressure is 1.5-3MPa, the reaction is stirred for 4-6 hours, cooled to room temperature, and then the catalyst and the reaction liquid are centrifuged and separated, and the reaction liquid is vacuum distilled to obtain the product.

[0015] In the method for using the above-mentioned single-atom palladium / graphene catalyst for the production of N,N,N'-trimethyl-N'-hydroxyethylethylenediamine, hydroxyethylethylenediamine and paraformaldehyde are used as raw materials to react and prepare N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine.

[0016] In summary, the raw materials used in the existing preparation methods of N,N,N'-trimethyl-N'-hydroxyethylethylenediamine all contain paraformaldehyde, which makes the reaction environment toxic to a certain extent. In addition to the wastewater generated by the reaction, a small amount of formaldehyde will be entrained in the product, which is not in line with the concept of green environmental protection. Summary of the invention

[0017] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine to solve the problem in the prior art that the raw materials include paraformaldehyde, which makes the reaction environment toxic to a certain extent, and in addition to the waste water generated by the reaction, a small amount of formaldehyde is entrained in the product, which does not conform to the concept of green environmental protection.

[0018] To achieve the above object, the present invention adopts the following technical scheme: a method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine, comprising the following steps:

[0019] Synthesis: It is prepared by reacting primary alcohols and secondary amines with -OH as raw materials in the presence of hydrogen.

[0020] Furthermore, the reaction pressure in the hydrogen environment is 0.2-0.5 MPa.

[0021] Furthermore, the reaction temperature in the hydrogen environment is 160-220°C.

[0022] Furthermore, the catalyst in the hydrogen environment is a platinum or palladium supported catalyst or a Ni-Cu-Mg-Fe quaternary supported catalyst.

[0023] Furthermore, in the platinum or palladium supported catalyst, the carrier is activated carbon, graphene or hydrotalcite.

[0024] Furthermore, in the platinum or palladium supported catalyst, the weight percentage of platinum or palladium is 5-8%.

[0025] Furthermore, the primary alcohol substance with -OH is N,N-dimethylethanolamine.

[0026] Furthermore, the secondary amine substance is N-methyl monoethanolamine.

[0027] Furthermore, calculated by molar mass, the molar ratio of the N,N-dimethylethanolamine to the N-methylmonoethanolamine is 1:1.03-1:1.05.

[0028] Further, the method further comprises the following steps:

[0029] Filtration: filtering the synthetic product obtained in the synthesis step to obtain a filtrate;

[0030] Purification: Remove light components by reduced pressure distillation under vacuum conditions of -100KPa--90KPa and distillation temperature of 93-98℃.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The invention uses -OH primary alcohol substances and secondary amine substances as raw materials, reacts in a hydrogen environment to prepare N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine, does not introduce formaldehyde, thus greatly reducing the toxicity of the reaction environment, and simultaneously the product does not carry formaldehyde, making it more environmentally friendly. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below through specific embodiments:

[0034] Example 1

[0035] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0036] 1. Synthesis

[0037] Weigh 178g of N,N-dimethylethanolamine and 1.6802g of catalyst into a 500ml reactor, wherein the catalyst is a supported catalyst whose carrier is activated carbon and whose active component is platinum, and the weight percentage of platinum in the supported catalyst is 5%;

[0038] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 190℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0039] 154.5 g of N-methylmonoethanolamine was added dropwise to the reaction kettle using a micro-inlet pump, and the addition was completed over 3 hours;

[0040] After the addition was completed, the mixture was kept warm for 2 hours, and a sample was taken for gas chromatography analysis, and the product purity was 92.5%.

[0041] 2. Filter

[0042] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0043] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 30 min.

[0044] 3. Distillation and purification

[0045] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -96 KPa and a distillation temperature of 95 °C;

[0046] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 268g of product was collected; after testing and analysis, the yield of the product was 91.8% and the purity was 99.5%.

[0047] Example 2

[0048] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0049] 1. Synthesis

[0050] Weigh 178g of N,N-dimethylethanolamine and 1.6802g of catalyst into a 500ml reactor, wherein the catalyst is a supported catalyst with graphene as the carrier and palladium as the active component, and the weight percentage of palladium in the supported catalyst is 8%;

[0051] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 160℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0052] 157.5 g of N-methylmonoethanolamine was added dropwise to the reaction kettle using a micro-inlet pump, and the addition was completed over 3 hours;

[0053] After the addition was completed, the mixture was kept warm for 2.5 hours, and a sample was taken for gas chromatography analysis, and the product purity was 92.9%.

[0054] 2. Filter

[0055] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0056] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 35 min.

[0057] 3. Distillation and purification

[0058] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -100 KPa and the distillation temperature was 93 °C;

[0059] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 275 g of the collected product was obtained; after testing and analysis, the yield of the product was 94.2% and the purity was 99.7%.

[0060] Example 3

[0061] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0062] 1. Synthesis

[0063] Weigh 178g of N,N-dimethylethanolamine and 1.6802g of catalyst into a 500ml reactor, wherein the catalyst is a supported catalyst whose carrier is hydrotalcite and whose active component is palladium, and the weight percentage of platinum in the supported catalyst is 8%;

[0064] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 220℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0065] 156 g of N-methyl monoethanolamine was added dropwise to the reactor using a micro-inlet pump and the addition was completed over 3 hours;

[0066] After the addition was completed, the mixture was kept warm for 2 hours, and a sample was taken for gas chromatography analysis, and the product purity was 91.7%.

[0067] 2. Filter

[0068] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0069] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 30 min.

[0070] 3. Distillation and purification

[0071] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -90 KPa and a distillation temperature of 98 °C;

[0072] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 278.2 g of the collected product was obtained; after testing and analysis, the yield of the product was 95.3% and the purity was 99.8%.

[0073] Example 4

[0074] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0075] 1. Synthesis

[0076] Weigh 178g of N,N-dimethylethanolamine and 1.6802g of catalyst into a 500ml reactor, wherein the catalyst is a supported catalyst whose carrier is activated carbon and whose active component is palladium, and the weight percentage of platinum in the supported catalyst is 6.5%;

[0077] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 200℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0078] 156.5 g of N-methylmonoethanolamine was added dropwise to the reaction kettle using a micro-inlet pump, and the addition was completed over 3 hours;

[0079] After the addition was completed, the mixture was kept warm for 2.2 hours, and a sample was taken for gas chromatography analysis, which yielded a product purity of 92.1%.

[0080] 2. Filter

[0081] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0082] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 32 min.

[0083] 3. Distillation and purification

[0084] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -95 KPa and a distillation temperature of 96 °C;

[0085] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 272 g of product was collected; after testing and analysis, the yield of the product was 93.1% and the purity was 99.6%.

[0086] Example 5

[0087] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0088] 1. Synthesis

[0089] 178 g of N,N-dimethylethanolamine and 1.6802 g of catalyst were weighed and added into a 500 ml reaction kettle, wherein the catalyst was a Ni-Cu-Mg-Fe quaternary supported catalyst;

[0090] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 170℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0091] 155 g of N-methyl monoethanolamine was added dropwise to the reactor using a micro-inlet pump and the addition was completed over 3 hours;

[0092] After the addition was completed, the mixture was kept warm for 2.5 hours, and a sample was taken for gas chromatography analysis, and the product purity was 90.9%.

[0093] 2. Filter

[0094] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0095] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 35 min.

[0096] 3. Distillation and purification

[0097] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -90 KPa and a distillation temperature of 98 °C;

[0098] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 271.1 g of the collected product was obtained; after testing and analysis, the yield of the product was 92.8% and the purity was 99.4%.

[0099] Comparative Example 1

[0100] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0101] 1. Synthesis

[0102] Weigh 178g of N,N-dimethylethanolamine and 1.6802g of catalyst into a 500ml reactor, wherein the catalyst is a supported catalyst whose carrier is activated carbon and whose active component is platinum, and the weight percentage of platinum in the supported catalyst is 4%;

[0103] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 170℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0104] 154.5 g of N-methylmonoethanolamine was added dropwise to the reaction kettle using a micro-inlet pump, and the addition was completed over 3 hours;

[0105] After the addition was completed, the mixture was kept warm for 2 hours, and a sample was taken for gas chromatography analysis, and the product purity was 70.2%.

[0106] 2. Filter

[0107] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0108] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 30 min.

[0109] 3. Distillation and purification

[0110] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -96 KPa and a distillation temperature of 95 °C;

[0111] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 212.7 g of product was collected; after testing and analysis, the yield of the product was 72.8% and the purity was 89.8%.

[0112] Comparative Example 2

[0113] Preparation of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine

[0114] 1. Synthesis

[0115] Weigh 178g of N,N-dimethylethanolamine and 1.6802g of catalyst into a 500ml reactor, wherein the catalyst is a supported catalyst whose carrier is activated carbon and whose active component is platinum, and the weight percentage of platinum in the supported catalyst is 9%;

[0116] Start stirring, replace with N2 and H2 in turn, maintain 0.2MPa H2 pressure in the reactor after completion, and heat to 170℃. After the reactor temperature stabilizes, adjust the H2 pressure to 0.5MPa;

[0117] 154.5 g of N-methylmonoethanolamine was added dropwise to the reaction kettle using a micro-inlet pump, and the addition was completed over 3 hours;

[0118] After the addition was completed, the mixture was kept warm for 2 hours, and a sample was taken for gas chromatography analysis, and the product purity was 92.93%.

[0119] 2. Filter

[0120] The kettle temperature was cooled to below 60°C, and the reaction solution was transferred to a beaker and allowed to stand until it reached room temperature;

[0121] The catalyst was filtered out with a sand core solvent filter, and a 50 mm diameter microporous organic filter membrane (pore size 0.2 μm) was used to filter under negative pressure with a vacuum pump for 30 min.

[0122] 3. Distillation and purification

[0123] The filtered crude liquid was transferred to a 500 ml distillation flask for vacuum distillation, wherein the vacuum distillation conditions were -96 KPa and a distillation temperature of 95 °C;

[0124] The light components were removed by vacuum distillation, and a small amount of product was removed in the early stage of vacuum distillation, and finally 278.3 g of product was collected; after testing and analysis, the yield of the product was 95.32% and the purity was 99.81%.

[0125] Compared with the method for producing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine using a single-atom palladium / graphene catalyst with application number CN202110542511.6, the preparation method of N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine in the present invention has lower reaction pressure, relatively lower requirements for equipment, and safer reaction.

[0126] Comprehensive analysis of Example 1-Example 5 and Comparative Example 1-Comparative Example 2 shows that:

[0127] 1. In the platinum or palladium supported catalyst in the present application document, the weight percentage of platinum or palladium is 5-8% which is relatively better, because in Comparative Example 1, when the weight percentage of platinum or palladium is 4, the yield and purity of the product are greatly reduced; and in Comparative Example 2, when the weight percentage of platinum or palladium is 9, the yield and purity of the product increase slightly, and platinum or palladium is relatively expensive. Considering comprehensively, the weight percentage of platinum or palladium is 5-8% which is relatively better.

[0128] 2. In Example 5, a Ni-Cu-Mg-Fe quaternary supported catalyst was used as a catalyst for the reaction of N,N-dimethylethanolamine and N-methylmonoethanolamine, and the reaction formula is as follows:

[0129] ;

[0130] The Ni-Cu-Mg-Fe quaternary supported catalyst is low-cost. Cu in the active component of the catalyst is a metal element with hydrogenation function. With the addition of a suitable amount of Ni, the coverage of H2 can be increased while reducing the oligomerization characteristics of Cu. Fe is a structural additive and an activity enhancer, which can enhance the active sites of Ni, Cu and Mg elements exposed on the surface of the catalyst particles, greatly improving the performance of the supported catalyst. In addition, the synergistic effect of Fe and Mg can greatly promote the dispersion of the active components of the catalyst and the activity of the catalyst. Compared with platinum or palladium supported catalysts, in addition to excellent activity, Ni-Cu-Mg-Fe quaternary supported catalysts are not inferior in selectivity, and Ni-Cu-Mg-Fe quaternary supported catalysts have greater cost advantages in the reaction of N,N-dimethylethanolamine and N-methylmonoethanolamine.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine, characterized in that: The following steps are involved: Synthesis: It is prepared by using primary alcohols and secondary amines with -OH as raw materials and reacting in a hydrogen environment; The reaction pressure in the hydrogen environment is 0.2-0.5Mpa; The reaction temperature in the hydrogen environment is 160-220°C; The catalyst in the hydrogen environment is a platinum or palladium supported catalyst or a Ni-Cu-Mg-Fe quaternary supported catalyst; The primary alcohol substance with -OH is N,N-dimethylethanolamine; The secondary amine substance is N-methyl monoethanolamine.

2. The method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine according to claim 1, characterized in that: In the platinum or palladium supported catalyst, the carrier is activated carbon, graphene or hydrotalcite.

3. The method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine according to claim 1, characterized in that: In the platinum or palladium supported catalyst, the weight percentage of platinum or palladium is 5-8%.

4. The method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine according to claim 1, characterized in that: Calculated according to molar mass, the molar ratio of the N,N-dimethylethanolamine to the N-methylmonoethanolamine is 1:1.03-1:1.

05.

5. The method for preparing N,N,N'-trimethyl-N'-hydroxyethyl-ethylenediamine according to claim 1, characterized in that: The following steps are also included: Filtration: filtering the synthetic product obtained in the synthetic step to obtain a filtrate; Purification: Remove light components by reduced pressure distillation under vacuum conditions of -100KPa--90KPa and distillation temperature of 93-98℃.