Method for continuous catalytic synthesis of 1, 2-cyclohexanediamine

Abstract

The invention relates to the technical field of compound synthesis, in particular to a method for continuous catalytic synthesis of 1, 2-cyclohexanediamine, which comprises the following steps: respectively preheating 2-aminocyclohexanol and ammonia which are used as raw materials to form a gaseous state, uniformly mixing the gaseous state in a premixer, and then feeding the gaseous state in a fixed bed reactor filled with a catalyst hydrogen-type MOR zeolite, the method comprises the following steps: carrying out ammoniation reaction by controlling the temperature of a reactor to be 200-300 DEG C and the pressure of a system to be 0.1-1 MPa, and carrying out separation and purification to obtain a target product 1, 2-cyclohexanediamine, according to the method, the MOR zeolite with the nanometer particle size is adopted as the catalyst, ammoniation of the 2-aminocyclohexanol can be catalyzed at the low pressure and temperature to obtain the 1, 2-cyclohexanediamine, the conversion per pass of the 2-aminocyclohexanol raw material is as high as 70% or above, the selectivity of the product 1, 2-cyclohexanediamine is as high as 85% or above, and the variety of by-products is few.

Description

Technical Field

[0001] The present invention relates to the technical field of compound synthesis, and particularly relates to a method for continuously catalytically synthesizing 1,2-cyclohexanediamine. Background Art

[0002] 1,2-Cyclohexanediamine, with the chemical formula C 6 H 14 N 2 , belongs to aliphatic diamine compounds. It is a colorless or light yellow transparent liquid with a strong ammonia smell, a boiling point of about 247 °C, and a relative density of about 0.905 g / cm 3 . 1,2-Cyclohexanediamine is easily hygroscopic in the air and can be miscible with water in any proportion. Common application fields of 1,2-cyclohexanediamine: It is often used for the curing of epoxy resins, and can undergo a cross-linking reaction with epoxy resins to form cured products with excellent mechanical properties and heat resistance; in the polyurethane industry, it can be used as a hard segment raw material for preparing polyurethane foams, elastomers, adhesives, etc.; it can also be used for synthesizing various pharmaceutical intermediates, and then preparing antibiotics, anti-tumor drugs, etc.; in the dye industry, it is used for synthesizing certain azo dyes and pigments; it can also be used as a raw material for surfactants to prepare detergents, emulsifiers, etc.; in addition, it can be used as a metal ion extractant in hydrometallurgy.

[0003] In existing methods for preparing 1,2-cyclohexanediamine, most of them adopt the process of reductive amination, that is, under the condition of containing hydrogen and the action of a catalyst. For example, CN106631819B, CN117599793A, etc. are all catalytically prepared under the condition of containing hydrogen and at high temperature and / or high pressure. The catalyst selects heavy metal and / or noble metal supported catalysts, and catalyst carriers include, for example, alumina, activated carbon, titanium oxide, silicon oxide, magnesium oxide, tin oxide, hydrotalcite, etc. Most of the existing technologies are carried out in a reducing atmosphere, and the system pressure is relatively high, the single-pass conversion rate is low, and the types of by-products are many. There are generally problems such as high production cost, complex process flow, and low yield. The present invention aims to develop a method for continuously catalytically synthesizing 1,2-cyclohexanediamine with high efficiency and high yield. Summary of the Invention

[0004] In order to solve the above technical problems, a method for continuously catalytically synthesizing 1,2-cyclohexanediamine is provided. The present invention uses MOR zeolite with a nano-sized particle diameter as a catalyst, and can catalyze the ammoniation of 2-aminocyclohexanol to obtain 1,2-cyclohexanediamine at a relatively low pressure and temperature. The conversion rate of the 2-aminocyclohexanol raw material can be as high as more than 70%, and the selectivity of the product 1,2-cyclohexanediamine can be as high as more than 85%, and the types of by-products are few; the present invention adopts a continuous process, with a high single-pass conversion rate, high selectivity of the target product, mild process conditions, good catalyst stability, and few types of by-products.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] A method for continuously catalytically synthesizing 1,2-cyclohexanediamine, comprising the following steps:

[0007] Using 2-aminocyclohexanol and ammonia as raw materials, preheating them to form gases respectively and then entering a premixer to be mixed evenly, and then entering a fixed-bed reactor filled with a catalyst hydrogen-form MOR zeolite. Control the reactor temperature within the range of 200°C - 300°C and the system pressure at 0.1 MPa - 1 MPa for the ammoniation reaction, and obtain the target product 1,2-cyclohexanediamine through separation and purification. The preheating temperature is set around the boiling point of 2-aminocyclohexanol, and the preheating temperature of ammonia is the same as that, to ensure that there is no temperature difference between the two and guarantee the subsequent catalytic reaction process.

[0008] Further, the median particle size of the hydrogen-form MOR zeolite is within the range of 200 nm - 800 nm, and the specific surface area is within the range of 350 m 2 / g - 400 m 2 / g.

[0009] Still further, the hydrogen-form MOR zeolite is loaded or not loaded with an active metal component. The active metal component is selected from one or more of La, Re, and cuprous. Among them, the loading amount of La is 0 - 0.2 wt%, and La can improve the catalyst stability; the loading amount of Re is 0 - 0.05 wt%, and Re can improve the catalyst anti-coking ability; the loading amount of cuprous Cu(I) is 0 - 0.2 wt%, and cuprous can improve the catalyst activity. The three can be loaded simultaneously, or separately, or in pairs.

[0010] Usually, Na-form MOR zeolite is used as the raw material for acidification to exchange sodium cations, and then it is loaded or not loaded with an active metal component and obtained after calcination. Na-form MOR zeolite does not have catalytic activity. There are many records on the loading of molecular sieves in the prior art, and the method for loading metals on the hydrogen-form MOR zeolite in this case is a conventional technology.

[0011] Still further, the loading height of the hydrogen-form MOR zeolite is 40% - 70% of the reaction tube length, and the bulk density is 0.4 - 0.8 g / mL.

[0012] Further, the inlet temperature of the fixed-bed reactor is set within the range of 205°C - 230°C, and the outlet temperature of the fixed-bed reactor is set within the range of 235°C - 250°C.

[0013] Further, the molar ratio of the 2-aminocyclohexanol to the ammonia is 1:3 - 30. The larger the ratio of ammonia, the higher the selectivity of the target product 1,2-cyclohexanediamine; when the molar ratio of 2-aminocyclohexanol to ammonia is 1:20, the selectivity of the target product 1,2-cyclohexanediamine exceeds 92%.

[0014] Beneficial technical effects:

[0015] The present invention uses 2-aminocyclohexanol and ammonia as raw materials to carry out a catalytic reaction in a fixed-bed reactor. The reaction uses nano-scale mordenite as a catalyst, and can effectively prepare 1,2-cyclohexanediamine under relatively mild reaction conditions; the present invention realizes a continuous production process, which not only improves production efficiency but also reduces energy consumption; during the reaction process, the single-pass conversion rate of the raw materials is relatively high, the selectivity of the target product is relatively high, and the types of by-products are few; at the same time, the catalyst used has good stability and a long service life, reducing the replacement frequency; the method of the present invention provides a new solution for the industrial production of 1,2-cyclohexanediamine and has good industrial application value. Description of the drawings

[0016] Figure 1 It is a process flow diagram for the continuous catalytic synthesis of 1,2-cyclohexanediamine according to the present invention. Specific embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Technologies and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies and methods should be regarded as part of the specification. In all examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0019] The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards; if there are no corresponding national standards, they are carried out according to general standard requirements or general methods.

[0020] Example 1

[0021] A method for continuously catalytically synthesizing 1,2 - cyclohexanediamine, the process flow chart is as shown in Figure 1 and includes the following steps:

[0022] Heat 2 - aminocyclohexanol to 60 °C and feed it into the pre - heater at a flow rate of 0.115 g / min. The temperature of the pre - heater is 200 °C. After pre - heating, 2 - aminocyclohexanol is converted into gas and enters the pre - mixer.

[0023] Ammonia enters another pre - heater at a flow rate of 120.0 mL / min. The temperature of the pre - heater is 200 °C. After pre - heating, ammonia enters the pre - mixer and mixes with gaseous 2 - aminocyclohexanol (the molar ratio of 2 - aminocyclohexanol to ammonia is about 1:5.4).

[0024] After ammonia and 2 - aminocyclohexanol are evenly mixed in the pre - mixer, they enter a fixed - bed reactor (the inner diameter of the reactor tube is 8 mm and the tube length is 30 cm). The reactor is filled with a catalyst, hydrogen - type MOR zeolite (prepared by acidifying Na - type MOR zeolite and then loading 0.1 wt% La and 0.02 wt% Re of active metal components). The inlet temperature of the fixed - bed reactor is 220 °C, the system pressure is 0.1 MPa. The filling height of the hydrogen - type MOR zeolite on the catalyst bed is 10 cm, the bulk density is 0.6 g / mL, the median particle size is 300 nm, and the specific surface area is in the range of 350 m 2 / g - 400 m 2 / g. The outlet temperature of the fixed - bed reactor is 245 °C. After the catalytic ammoniation reaction, the material flows out and is cooled to 20 °C through gas - liquid separation and heat exchanger.

[0025] Detect the gas - phase and liquid - phase compositions respectively. The main component in the gas phase is ammonia, with a volume fraction ≥ 99.0%; the liquid phase is a material containing the target product 1,2 - cyclohexanediamine. In addition to the target product, there are unreacted raw material 2 - aminocyclohexanol and by - products (the main by - products are tetradecahydrophenazine and hydrogenated phenoxazine).

[0026] Subsequently, the target product 1,2 - cyclohexanediamine can be separated by vacuum distillation (the boiling points of the by - products are higher than that of the target product, and the target product is easy to separate). The distillation rate is at least 85 wt%. To improve the yield of the target product, the distillate can be further rectified. This invention only discusses the liquid - phase composition.

[0027] In this case, the single - pass conversion rate of the raw material 2 - aminocyclohexanol is 70.5%, the selectivity of the target product 1,2 - cyclohexanediamine is 85%, the selectivity of tetradecahydrophenazine is 8.5%, and the selectivity of hydrogenated phenoxazine is 2.5%.

[0028] The catalyst activity did not decrease after continuous reaction for 120 hours; after continuous reaction for 240 hours, the catalyst activity did not decrease significantly (the decrease in raw material conversion rate was no more than 5%).

[0029] Example 2

[0030] A method for continuously catalytically synthesizing 1,2-cyclohexanediamine, comprising the following steps:

[0031] Heat 2-aminocyclohexanol to 60 °C and feed it into the preheater at a flow rate of 0.200 g / min. The temperature of the preheater is 200 °C. After preheating, 2-aminocyclohexanol is converted into a gas and enters the premixer;

[0032] Ammonia enters another preheater at a flow rate of 120.0 mL / min. The temperature of the preheater is 200 °C. After preheating, ammonia enters the premixer and mixes with gaseous 2-aminocyclohexanol (the molar ratio of 2-aminocyclohexanol to ammonia is about 1:3.1);

[0033] After ammonia and 2-aminocyclohexanol are mixed evenly in the premixer, they enter the fixed-bed reactor. The reactor is filled with the catalyst hydrogen-form MOR zeolite (only loaded with 0.1 wt% La of active metal components after acidification treatment using Na-type MOR zeolite as the raw material). The inlet temperature of the fixed-bed reactor is 240 °C, the system pressure is 0.1 MPa, the loading height of the hydrogen-form MOR zeolite on the catalyst bed is 10 cm, the bulk density is 0.8 g / mL, the median particle size is 300 nm, and the specific surface area is in the range of 350 m 2 / g - 400 m 2 / g. The outlet temperature of the fixed-bed reactor is 250 °C. After the catalytic ammoniation reaction, the material flows out and is cooled to 20 °C through gas-liquid separation and heat exchanger.

[0034] Detect the gas-phase and liquid-phase compositions respectively. The main component in the gas phase is ammonia, with a volume fraction of ≥99.0%; the liquid phase is the material containing the target product 1,2-cyclohexanediamine. In addition to the target product, there are unreacted raw material 2-aminocyclohexanol and by-products (the main by-products are tetradecahydrophenazine and hydrogenated phenoxazine).

[0035] Subsequently, the target product 1,2-cyclohexanediamine can be separated by vacuum distillation (the boiling points of the by-products are higher than that of the target product, and the target product is easy to separate), and the distillation rate is at least 85 wt%. To improve the yield of the target product, the distillate can be further rectified. This invention only discusses the liquid-phase composition.

[0036] In this case, the single-pass conversion rate of the raw material 2-aminocyclohexanol is 75.6%, the selectivity of the target product 1,2-cyclohexanediamine is 80%, the selectivity of tetradecahydrophenazine is 9.8%, and the selectivity of hydrogenated phenoxazine is 5.5%.

[0037] The catalyst activity did not decrease significantly after 180 hours of continuous reaction (the decrease in the raw material conversion rate was no more than 5%).

[0038] Example 3

[0039] The method for continuously catalytically synthesizing 1,2 - cyclohexanediamine in this case is the same as that in Example 1, except that the catalyst used is: hydrogen - type MOR zeolite (loaded with 0.2 wt% Cu(I) of active metal component).

[0040] The single - pass conversion rate of the raw material 2 - aminocyclohexanol in this case is 85%, the selectivity of the target product 1,2 - cyclohexanediamine is 87.5%, the selectivity of tetradecahydrophenazine is 7.8%, and the selectivity of hydrogenated phenoxazine is 1.5%.

[0041] After 24 hours of continuous reaction, the catalyst activity did not decrease significantly (the decrease in the raw material conversion rate was no more than 5%).

[0042] Comparative Example 1

[0043] The preparation process of 1,2 - cyclohexanediamine in this case is the same as that in Example 1, except that the molar ratio of 2 - aminocyclohexanol to ammonia is 1:1.

[0044] The single - pass conversion rate of the raw material 2 - aminocyclohexanol in this case is 85%, the selectivity of the target product 1,2 - cyclohexanediamine is 67.5%, the selectivity of tetradecahydrophenazine is 18.6%, and the selectivity of hydrogenated phenoxazine is 11.5%.

[0045] Comparative Example 2

[0046] The preparation process of 1,2 - cyclohexanediamine in this case is the same as that in Example 1, except that the catalyst used is un - acidified Na - type MOR zeolite (not loaded with active metal component, median particle size 300 nm).

[0047] The single - pass conversion rate of the raw material 2 - aminocyclohexanol in this case is 20.8%, the selectivity of the target product 1,2 - cyclohexanediamine is 57.5%, the selectivity of tetradecahydrophenazine is 18.6%, and the selectivity of hydrogenated phenoxazine is 13.5%.

[0048] Comparative Example 3

[0049] The preparation process of 1,2 - cyclohexanediamine in this case is the same as that in Example 1, except that the catalyst used is hydrogen - type ZSM - 5 zeolite (not loaded with active metal component, median particle size 300 nm).

[0050] In this example, the single-pass conversion rate of the raw material 2-aminocyclohexanol is 75%, the selectivity of the target product 1,2-cyclohexanediamine is 77.5%, the selectivity of tetradecahydrophenazine is 11.6%, and the selectivity of hydrogenated phenoxazine is 8.5%.

[0051] After continuous reaction for 12 hours, the catalyst stability is poor. As a catalyst, hydrogen-type ZSM-5 zeolite is extremely prone to deactivation, and the raw material conversion rate drops by more than 5%.

[0052] Comparative Example 4

[0053] The preparation process of 1,2-cyclohexanediamine in this example is the same as that in Example 1, except that the catalyst used is hydrogen-type Y zeolite (without loaded active metal components, median particle size 300 nm).

[0054] In this example, the single-pass conversion rate of the raw material 2-aminocyclohexanol is 65%, the selectivity of the target product 1,2-cyclohexanediamine is 72.5%, the selectivity of tetradecahydrophenazine is 14.6%, and the selectivity of hydrogenated phenoxazine is 9.5%.

[0055] After continuous reaction for 24 hours, the stability of hydrogen-type Y zeolite as a catalyst is not good, and the raw material conversion rate drops by more than 5%.

[0056] Comparative Example 5

[0057] The preparation process of 1,2-cyclohexanediamine in this example is the same as that in Example 1, except that the median particle size of the catalyst is 800 nm.

[0058] In this example, the single-pass conversion rate of the raw material 2-aminocyclohexanol is 68.3%, the selectivity of the target product 1,2-cyclohexanediamine is 86%, the selectivity of tetradecahydrophenazine is 12.8%, and the selectivity of hydrogenated phenoxazine is 2.5%.

[0059] After continuous reaction for 120 hours, the catalyst activity does not decrease significantly (the raw material conversion rate drops by no more than 5%). In this example, the raw material conversion rate decreases slightly, and the selectivity of by-products increases.

[0060] When considering factors such as catalytic activity and product diffusion, selecting a suitable nano-MOR zeolite is the key to the present invention. Loading Re and / or La active metal components on the nano-MOR zeolite can greatly improve the catalyst stability; the loaded Cu(I) can improve the catalyst activity, and the presence of Cu(I) can, to a certain extent, cover up the deficiency of large particle size (such as in Comparative Example 4).

[0061] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A method for continuous catalytic synthesis of 1,2-cyclohexanediamine, characterized in that: The steps include: 2-Aminocyclohexanol and ammonia are used as raw materials, which are preheated to form gaseous state and then enter into a premixer for uniform mixing, and then enter into a fixed bed reactor, in which a catalyst hydrogen-type MOR zeolite is loaded. The reactor temperature is controlled within the range of 200°C-300°C and the system pressure is controlled within the range of 0.1MPa-1MPa for amination reaction, and the target product 1,2-cyclohexanediamine is obtained through separation and purification.

2. The method for continuous catalytic synthesis of 1,2-cyclohexanediamine according to claim 1, characterized in that: The median particle size of the hydrogen-type MOR zeolite is in the range of 200nm-800nm, and the specific surface area is 350m 2 / g-400m 2 / g range.

3. The method for continuous catalytic synthesis of 1,2-cyclohexanediamine according to claim 2, characterized in that: The hydrogen-type MOR zeolite may or may not be loaded with an active metal component, and the active metal component is selected from one or more of La, Re, and cuprous.

4. The method for continuous catalytic synthesis of 1,2-cyclohexanediamine according to claim 3, characterized in that: The loading amount of La is 0-0.2wt%; the loading amount of Re is 0-0.05wt%; and the loading amount of cuprous is 0-0.2wt%.

5. A method for continuous catalytic synthesis of 1,2-cyclohexanediamine according to any one of claims 1 to 4, characterized in that: The filling height of the hydrogen-type MOR zeolite is 40%-70% of the length of the reaction tube, and the bulk density is 0.4-0.8 g / mL.

6. The method for continuous catalytic synthesis of 1,2-cyclohexanediamine according to claim 5, characterized in that: The inlet temperature of the fixed bed reactor is set in the range of 205°C-230°C, and the outlet temperature of the fixed bed reactor is set in the range of 235°C-250°C.

7. The method for continuous catalytic synthesis of 1,2-cyclohexanediamine according to claim 5, characterized in that: The molar ratio of the 2-aminocyclohexanol to the ammonia is 1:3-30.

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