A process for the synthesis of 3-aminomethyl-3,5,5-trimethylcyclohexylamine, catalysts therefor and methods for their preparation

Abstract

The present application relates to a kind of method for synthesizing 3-amino methyl-3,5,5-trimethylcyclohexylamine, catalyst and its preparation method.The method is with isophorone nitrile, liquid ammonia and hydrogen as raw material, reaction is carried out in the presence of catalyst, obtain the 3-amino methyl-3,5,5-trimethylcyclohexylamine, the catalyst is supported catalyst, and include carrier and active metal supported on carrier, the carrier is CeO2 modified molecular sieve, the active metal includes Co and alkali metal.Preparation the catalyst, including the CeO2 modified molecular sieve is dipped in the mixed solution of cobalt salt and alkali metal salt, dry, calcination, reduction, obtain the step of the catalyst.The present application can significantly improve the selectivity and yield of target product under the premise of using small amount of active ingredient, and catalyst post-processing is simple.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, a catalyst and a preparation method thereof. BACKGROUND

[0002] 3-aminomethyl-3,5,5-trimethylcyclohexylamine (commonly known as isophorone diamine, abbreviated as IPDA) is mainly used as a curing agent for epoxy resins, and it can also be used as a crosslinking agent, a coupling agent and a hydroxyl stabilizer in the production of polyurethane, and a special monomer, and it can also be used to prepare the corresponding isophorone diisocyanate. IPDA can also be used as an amine component raw material during polyamide polymerization. In addition, due to the easy modification of IPDA, its modified products play an indispensable role in the adhesive for magnetic tape, the adhesive for soft packaging composite film, the ink industry, and the pesticide industry, and the pharmaceutical industry.

[0003] IPDA is usually synthesized by amination of isophorone nitrile (abbreviated as IPN) and hydrogenation reaction. The hydrogenation reaction often requires the addition of a catalyst, and the commonly used hydrogenation catalysts are mainly supported catalysts, and the commonly used supports are silicon-based materials, alumina, activated carbon, etc. Molecular sieve is a commonly used silicon-based material support, which has the following advantages: (1) the molecular sieve support has a regular and stable skeletal structure and a high specific surface area, which endows it with high temperature resistance and hydrothermal stability, ensures the high diffusion of active metal and the efficient diffusion of reactants and products, and promotes the rapid progress of the reaction. (2) The molecular sieve fixes the active metal positive ions through electrostatic balance, thereby improving the stability of the active metal ions. (3) Due to the electrostatic stabilization effect, the loading amount and distribution of the active metal on the molecular sieve can also be adjusted by efficiently matching the silica-alumina ratio (in silica-alumina molecular sieve) or the Si content (in silica-alumina-phosphorus molecular sieve) of the molecular sieve support and the loading amount of the metal species, thereby further improving the activity and hydrothermal stability of the catalyst.

[0004] Chinese authorized patent CN114380699B discloses a catalyst with ZSM-5 molecular sieve as a carrier, which is prepared by multiple heat impregnation and evaporation drying to improve the loading amount of active components (metal oxides such as cobalt oxide), and the preparation process of the catalyst includes calcining a metal salt to obtain an active metal oxide, then loading an ionic liquid, and then reducing to obtain a supported catalyst for IPDA synthesis, but when the catalyst is used for synthesizing isophorone diamine IPDA, the selectivity of the target product is 89.8%, and the selectivity still has room for improvement.

[0005] For the supported catalyst, high dispersion and high loading of the active metal component are often difficult to achieve simultaneously. When the loading of the active metal component is high, the active component is prone to aggregation and difficult to be highly uniformly dispersed, which reduces the catalytic activity. When the loading of the active metal component is low, although the aggregation of the active component can be significantly reduced, the content of the active component is insufficient, which also leads to a significant reduction in the catalytic activity of the catalyst. Therefore, for the supported catalyst, how to control the aggregation of the active component when the content of the active component is high or how to maintain a high catalytic activity when the content of the active component is low is the direction of efforts in this field. SUMMARY

[0006] In view of the shortcomings and deficiencies of the prior art, the present application provides an improved method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, which uses a new catalyst to significantly improve the selectivity and yield of the target product under the premise of using a small amount of active component, and the catalyst is easy to handle.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, which uses isophorone nitrile, liquid ammonia and hydrogen as raw materials, and reacts in the presence of a catalyst to obtain the 3-aminomethyl-3,5,5-trimethylcyclohexylamine, the catalyst is a supported catalyst, and includes a carrier and an active metal supported on the carrier, the carrier is a CeO2 modified molecular sieve, and the active metal includes Co and an alkali metal.

[0009] In the present application, the alkali metal refers to lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs).

[0010] The inventors have found that modifying the molecular sieve with CeO2 can increase the surface area and pore size of the molecular sieve carrier, so that the active metal component supported on the carrier exposes a larger catalytic surface during the catalytic reaction, thereby improving the catalytic efficiency. At the same time, the modified molecular sieve anchors the active metal cobalt by electrostatic balance, improves the stability of the active metal component, reduces the acid density of the molecular sieve, and reduces the aggregation degree of the supported active metal component, thereby improving the dispersion uniformity and further improving the catalytic efficiency of the catalyst. In addition, by adding an alkali metal component in addition to the conventional cobalt, the catalyst has higher heterogeneous hydrogen activation capacity and hydrogen overflow strength, which increases the structural stability of the catalyst. When the catalyst is used for the synthesis of IPDA, the yield and selectivity of IPDA are significantly improved, and the content of by-products such as de-cyanated products (mainly trimethylcyclohexylamine and trimethylcyclohexanol, etc.) is significantly reduced.

[0011] In some embodiments, the alkali metal is Na or K.

[0012] In some embodiments, the catalyst contains 0.2%-1.0% Co and 0.5%-2.5% alkali metal by weight percentage.

[0013] In some embodiments, the catalyst contains 0.2%-1.0% Co and 0.8%-2.0% alkali metal by weight percentage.

[0014] In some embodiments, the catalyst contains, by weight percentage, 0.2%-1.0% Co and 0.8%-2.0% alkali metal, wherein the alkali metal is Na or K.

[0015] In some embodiments, the CeO2-modified molecular sieve contains 1.5%-35% CeO2 by mass.

[0016] In some embodiments, the molecular sieve is selected from one or more combinations of ZSM-5 molecular sieve, Y-type molecular sieve, Beta molecular sieve, SBA-15 molecular sieve, TS-1 molecular sieve, and Ti-MWW molecular sieve.

[0017] In some embodiments, the CeO2-modified molecular sieve is prepared by a method comprising the following steps: subjecting the molecular sieve, cerium salt solution, and alkali to a precipitation reaction, followed by filtration, drying, and calcination to obtain the CeO2-modified molecular sieve.

[0018] In some embodiments, the cerium salt is selected from one or more combinations of cerium nitrate, cerium chloride, and cerium sulfate.

[0019] In some embodiments, the alkali is selected from one or more combinations of ammonia, sodium bicarbonate, and triammonium phosphate.

[0020] In some embodiments, the precipitation reaction is carried out at a pH of 5-7.

[0021] In some embodiments, the catalyst is prepared by a method comprising the following steps: impregnating the CeO2-modified molecular sieve in a mixed solution of cobalt salt and alkali metal salt, drying, calcining, and reducing to obtain the catalyst.

[0022] In some embodiments, the cobalt salt is selected from one or more combinations of cobalt nitrate, cobalt chloride, cobalt sulfate, and cobalt carbonate.

[0023] In some embodiments, the alkali metal salt is selected from one or more combinations of sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, sodium carbonate, and potassium carbonate.

[0024] In some embodiments, the impregnation is performed for multiple times.

[0025] In some embodiments, the reduction is performed under a hydrogen atmosphere.

[0026] In some embodiments, the reduction is performed in a fixed bed reactor.

[0027] In some embodiments, the method comprises the following steps:

[0028] 1) loading the catalyst into a fixed bed reactor;

[0029] 2) feeding the isophorone nitrile, liquid ammonia and hydrogen into the fixed bed reactor to perform a reaction to obtain the 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

[0030] In some embodiments, the space-time handling capacity of the catalyst is 2.5-5 mol / (L*h).

[0031] In some embodiments, the feeding rate of the isophorone nitrile is 100-400 g / h, the feeding rate of the liquid ammonia is 500-1500 g / h, and the feeding rate of the hydrogen is 50-200 L / h.

[0032] In some embodiments, the temperature of the reaction is 80-160℃.

[0033] In some embodiments, the pressure of the reaction is 10-50 MPa.

[0034] In some embodiments, the time of the reaction is 0.5-6 h.

[0035] The present application further provides the above-mentioned catalyst. The catalyst can significantly improve the selectivity and yield of the target product under the premise of using a small amount of active ingredients, and the post-reaction treatment is simple after being used for catalyzing a reaction.

[0036] The present application further provides a preparation method of the above-mentioned catalyst, which comprises the step of impregnating the CeO2 modified molecular sieve in a mixed solution of a cobalt salt and an alkali metal salt, drying, calcining, and reducing to obtain the catalyst.

[0037] In some embodiments, the preparation method further comprises the step of performing a precipitation reaction on a molecular sieve, a cerium salt solution, and a base, and filtering, drying, and calcining to obtain the CeO2 modified molecular sieve.

[0038] Compared with the prior art, the present application has the following advantages:

[0039] The synthesis method of the present application can obviously improve the selectivity and yield of the target product, obviously reduce the content of conventional by-products, and the catalyst post-processing is simple, the yield of the target product IPDA can reach 99.04%, the content of decyano by-product can be controlled below 0.28%, and the space-time treatment capacity of the catalyst can reach 5.0 mol / (L*h).

[0040] The synthesis method of the present application adopts a new catalyst, in which the molecular sieve is modified by CeO2 and used as a carrier part of the catalyst, so that the surface area and pore size of the molecular sieve carrier can be increased, so that the active metal component loaded on the carrier can expose a larger catalytic surface during catalytic reaction, thereby improving the catalytic efficiency, and the modified molecular sieve can anchor the active metal cobalt by electrostatic balance, improve the stability of the metal active component, and reduce the acid density of the molecular sieve and the aggregation degree of the loaded active metal component, improve the uniformity of dispersion, and further improve the catalytic efficiency of the catalyst.

[0041] In the catalyst of the present application, in addition to the conventional cobalt, the addition of an alkali metal component can make the catalyst have higher heterogeneous hydrogen activation capacity and hydrogen overflow strength, increase the structural stability of the catalyst, so that when it is used for catalyzing the synthesis of IPDA, the yield and selectivity of IPDA are obviously improved, and the content of by-products such as decyano products (mainly trimethylcyclohexylamine and trimethylcyclohexanol) is obviously reduced. DETAILED DESCRIPTION

[0042] The present application will be further described below in combination with examples. However, the present application is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the implementation conditions not marked are conventional conditions in the industry. The technical features involved in each embodiment of the present application can be combined with each other as long as they do not conflict with each other.

[0043] Example 1

[0044] The present embodiment provides a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), and the specific steps are as follows:

[0045] 1) Preparation of Beta molecular sieve

[0046] Zeolites were synthesized from a starting gel under conventional hydrothermal conditions at 140°C. 37.86 g of tetraethylammonium hydroxide TEAOH solution and a certain amount of NaAlO2 were mixed under continuous stirring. After stirring for 10 min, 1.07 g of sodium hydroxide dissolved in 6 g of deionized water was added to the solution. Then 37.55 g of silica was added to the above mixture under continuous stirring for 6 h. Finally, the reaction mixture was transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave and crystallized at 140°C for 6 days. The synthesized solid product was centrifuged, washed with deionized water, dried at 80°C, and calcined in air at 550°C for 6 h to remove the organic template, obtaining a calcined zeolite. 1 g of the calcined zeolite was added to 10 mL of 1 M aqueous ammonium nitrate solution and continuously stirred at 80°C for 2 h. The solid precipitate after centrifugation was dried at 80°C. This process was repeated three times, and the obtained sample was calcined in air at 450°C for 4 h to obtain a Beta molecular sieve with a silicon-aluminum ratio of 100.

[0047] 2) Preparation of CeO2 modified Beta molecular sieve

[0048] A cerium nitrate solution with a certain mass concentration was prepared, and ammonia water was added to adjust the pH to about 6. The Beta molecular sieve was added to the above solution, and the impregnation method was used to stir the reaction under water bath conditions, filter, dry in an oven, and calcine in a muffle furnace at 500°C for 2 hours to obtain a CeO2 modified Beta molecular sieve CeO2-Beta, wherein the mass percentage of CeO2 is 1.5%.

[0049] 3) Preparation of catalyst

[0050] 0.5 g of Co(NO3)2·6H2O and 1.7 g of NaNO3 were dissolved in 100 mL of water to prepare an impregnation solution. Then 97.6 g of CeO2-Beta molecular sieve carrier was impregnated with the above impregnation solution for several times, and then dried at 80°C in air for 24 h and calcined at 450°C in air for 10 h to obtain a catalyst precursor CoO-NaO / CeO2-Beta.

[0051] 100 g of the above catalyst precursor was loaded into a fixed bed reactor, and then reduced at 300°C under a pure hydrogen atmosphere for 48 h to obtain a Co-Na / CeO2-Beta catalyst, which contains 0.5% of Co and 1.7% of Na by weight percentage.

[0052] 4) Preparation of isophorone diamine

[0053] The Co-Na / CeO2-Beta catalyst 480 mL was loaded in a hydrogenation reactor, isophoronenitrile, liquid ammonia and hydrogen were introduced into the hydrogenation reactor, the feeding amount of isophoronenitrile was controlled to be 353 g / h, the feeding amount of liquid ammonia was 1500 g / h, and the feeding amount of hydrogen H2 was 200 L / h, the reaction was carried out at a hydrogen pressure of 30 MPa and a temperature of 120°C, at this time, the space-time yield of the catalyst was 5.0 mol / (L*h), then sampling and filtering were performed to obtain an isophorone diamine reaction liquid, and gas chromatography was used to detect the composition of the reaction liquid, the analysis test conditions of the gas chromatography were as follows: a DB-1 capillary column (30 m x 0.53 mm, 1.5 μm); the column oven temperature was 35°C, the valve oven temperature was 110°C, and the detector temperature was 205°C; the carrier gas was helium, the flow rate was 5 mL / min; the reference gas flow rate was 15 mL / min; the constant column flow rate and the tail blow flow rate were 10 mL / min; the sampling mode was split sampling, the split ratio was 5:1, and the sampling amount was 250 μL. The results are shown in Table 1 below, wherein the de-cyanated products are mainly trimethylcyclohexylamine and trimethylcyclohexanol, and IPDA refers to 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

[0054] Example 2

[0055] The present example provides a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as that of Example 1, except that the feeding amount of Co(NO3)2·6H2O in step 3) is changed, and the obtained catalyst contains 0.2% of Co and 1.7% of Na. The catalytic reaction results are shown in Table 1 below.

[0056] Example 3

[0057] The present example provides a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as that of Example 1, except that the feeding amount of Co(NO3)2·6H2O in step 3) is changed, and the obtained catalyst contains 1.0% of Co and 1.7% of Na. The catalytic reaction results are shown in Table 1 below.

[0058] Example 4

[0059] The present example provides a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as that of Example 1, except that the feeding amount of NaAlO2 in step 1) is changed, so that the silicon-aluminum ratio of the Beta molecular sieve obtained in step 1) is 40. The catalytic reaction results are shown in Table 1 below.

[0060] Example 5

[0061] This example provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as example 1, except that the amount of NaAlO2 in step 1) is changed so that the silica-alumina ratio of the Beta molecular sieve obtained in step 1) is 25. The results of the catalytic reaction are shown in Table 1 below.

[0062] Examples 6-10

[0063] Examples 6-10 provide a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as example 1, except that the amount of NaNO3 in step 3) is changed, and the contents of Co and Na in the obtained catalyst are shown in Table 1 below. The results of the catalytic reaction are shown in Table 1 below.

[0064] Example 11

[0065] This example provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as example 1, except that 1.7g of NaNO3 in step 3) is replaced by 1.7g of KNO3, and the contents of Co and K in the obtained catalyst are shown in Table 1 below. The results of the catalytic reaction are shown in Table 1 below.

[0066] Examples 12-16

[0067] Examples 12-16 provide a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as example 1, except that the Beta molecular sieve is replaced by ZSM-5 molecular sieve, Y-type molecular sieve, SBA-15 molecular sieve, TS-1 molecular sieve, and Ti-MWW molecular sieve, respectively. The results of the catalytic reaction are shown in Table 1 below.

[0068] Comparative Example 1

[0069] This comparative example provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as example 1, except that the impregnation solution in step 3) only contains Co(NO3)2·6H2O, but does not contain NaNO3, and the amount of Co(NO3)2·6H2O is controlled so that the obtained catalyst contains 0.5% of Co. The results of the catalytic reaction are shown in Table 1 below.

[0070] Comparative Example 2

[0071] The comparative example 2 provides a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as the example 1, the difference is only that the step 2) is not carried out, the Beta molecular sieve is directly used as the catalyst carrier, and the impregnation solution in the step 3) only contains Co(NO3)2·6H2O, and does not contain NaNO3, and the amount of Co(NO3)2·6H2O is controlled, so that the catalyst obtained contains 0.5% of Co. The catalytic reaction results are shown in the following table 1.

[0072] Comparative example 3

[0073] The comparative example 2 provides a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophorone diamine), which is basically the same as the example 1, the difference is only that the step 2) is not carried out, the Beta molecular sieve is directly used as the catalyst carrier. The catalytic reaction results are shown in the following table 1.

[0074] Table 1 Catalyst composition and catalytic results

[0075]

[0076] From the above table 1, it can be seen that the modification of the molecular sieve with CeO2 can improve the yield of the target product IPDA and reduce the content of the by-product decyano product, and the addition of the alkali metal to the cobalt in the active metal component can further improve the yield and selectivity of the IPDA and reduce the content of the by-product decyano product.

[0077] The above examples are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable the person skilled in the art to understand the content of the present application and to implement it, and it cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

[0078] The endpoints of the ranges and any values claimed herein are not limited to the precise values recited as exactly that endpoint. Any values that fall within common ranges of values are to be construed as not being limited to an exact range or value per se, unless the context clearly indicates otherwise. For values that fall within a range, the range endpoints are not to be understood as mutually exclusive of each other, and the endpoints and single points within the range are to be considered as being included in the range unless the context clearly indicates otherwise.

Claims

1. A method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, wherein the method uses isophorone nitrile, liquid ammonia, and hydrogen as raw materials, and reacts them in the presence of a catalyst to obtain the 3-aminomethyl-3,5,5-trimethylcyclohexylamine, characterized in that: The catalyst is a supported catalyst, comprising a support and an active metal supported on the support. The support is a CeO2-modified molecular sieve, and the active metal includes Co and an alkali metal. By weight percentage, the catalyst contains 0.2%-1.0% Co and 0.5%-2.5% alkali metal; the alkali metal is Na or K; and the CeO2-modified molecular sieve contains 1.5%-35% CeO2 by mass.

2. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The catalyst contains 0.2%-1.0% Co and 0.8%-2.0% alkali metals by weight percentage.

3. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The molecular sieve is selected from one or more of ZSM-5 molecular sieve, Y-type molecular sieve, Beta molecular sieve, SBA-15 molecular sieve, TS-1 molecular sieve, and Ti-MWW molecular sieve.

4. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The CeO2-modified molecular sieve is prepared by a method including the following steps: subjecting the molecular sieve, cerium salt solution, and alkali to a precipitation reaction, filtering, drying, and calcining to obtain the CeO2-modified molecular sieve.

5. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The catalyst is composed of The catalyst is prepared by a method including the following steps: impregnating the CeO2-modified molecular sieve in a mixed solution of cobalt salt and alkali metal salt, drying, calcining, and reducing to obtain the catalyst.

6. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The method includes the following steps: 1) The catalyst is loaded into a fixed-bed reactor; 2) The isophorone nitrile, liquid ammonia and hydrogen are introduced into the fixed-bed reactor to carry out the reaction and obtain the 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

7. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 6, characterized in that: The space-time throughput of the catalyst is 2.5-5 mol / (L*h).

8. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 6, characterized in that: The feed rate of the isophorone nitrile is 100-400 g / h, the feed rate of the liquid ammonia is 500-1500 g / h, and the feed rate of the hydrogen is 50-200 L / h.

Images