Preparation method for producing high-quality primary amine

Abstract

The invention relates to the technical field of primary amine production, and discloses a preparation method for high-quality primary amine production, which comprises the following steps: 1, preparing raw materials: selecting a proper amount of fatty acid, ammonia gas, hydrogen and a catalyst according to requirements; step 2, preparing fatty nitrile: adding fatty acid and ammonia gas into the reaction kettle for reaction to generate fatty acid ammonium salt, and then transferring the fatty acid ammonium salt of a catalyst into a dehydration tower for dehydration to generate fatty nitrile; step 3, purifying the fatty nitrile: transferring the fatty nitrile obtained in the step 2 into a gas phase reaction tower for further reaction to generate the fatty nitrile, so as to improve the purity of the fatty nitrile; and step 4, generation of fatty primary amine: adding the fatty nitrile obtained in the step 3 into a hydrogenation reactor, then adding hydrogen and a catalyst into the hydrogenation reactor, and enabling the fatty nitrile and the hydrogen to generate the fatty primary amine under the action of the catalyst. According to the method, the reaction temperature and pressure are reduced, energy is saved, the generation rate of the aliphatic primary amine can be increased, and the economic benefit is higher.

Description

Technical Field

[0001] The invention relates to the technical field of primary amine production, and in particular to a preparation method for producing high-quality primary amine. Background Art

[0002] Fatty primary amines refer to primary amines in a large class of organic amine compounds with carbon chain lengths ranging from C8 to C22. They are organic derivatives of ammonia and, like general amines, are divided into four categories: primary amines, secondary amines, tertiary amines, and polyamines. The primary amine depends on the number of hydrogen atoms in ammonia replaced by alkyl groups.

[0003] At present, when producing fatty primary amines, it is necessary to first use fatty acids and ammonia to react in a reactor to generate fatty acid ammonium salts, and the reaction temperature is above 320°C. Then, the fatty acid ammonium salts and hydrogen are reacted in a hydrogenation reactor to generate fatty primary amines. The reaction temperature is above 200°C and the pressure is above 3MPa. It consumes a lot of energy, and the generation rate of fatty primary amines is not high enough, and the economic benefits are poor. Therefore, in view of the above situation, it is urgent to develop a preparation method for the production of high-quality primary amines that can reduce the reaction temperature and pressure, save energy, and increase the generation rate of fatty primary amines, so as to overcome the shortcomings in current practical applications and meet current needs. Summary of the invention

[0004] The object of the present invention is to provide a preparation method for producing high-quality primary amines to solve the problems raised in the above background technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A preparation method for producing high-quality primary amines comprises the following steps:

[0007] Step 1: Preparation of raw materials: Select appropriate amounts of fatty acid, ammonia, hydrogen and catalyst according to demand;

[0008] Step 2, preparation of fatty nitrile: adding fatty acid and ammonia into a reactor to react to generate fatty acid ammonium salt, controlling the reaction temperature in the reactor at 280-320° C. through a heat exchanger, and then transferring the fatty acid ammonium salt of the catalyst to a dehydration tower for dehydration to generate fatty nitrile;

[0009] Step 3, purification of fatty nitrile: the fatty nitrile obtained in step 2 is transferred to a gas phase reaction tower for further reaction to generate fatty nitrile, thereby improving the purity of the fatty nitrile;

[0010] Step 4: Generation of fatty primary amines: Add the fatty nitrile obtained in step 3 to a hydrogenation reactor, and then add hydrogen and a catalyst to the hydrogenation reactor, so that the fatty nitrile and hydrogen generate fatty primary amines under the action of the catalyst. The temperature in the hydrogenation reactor is 100-150° C. and the pressure is 1-3 MPa.

[0011] Step 5: Recovery of the catalyst: Add the product obtained in step 4 into a catalyst filtering device, and filter and recover the catalyst therein;

[0012] Step 6: Purification: The product filtered in step 5 is added into a distillation tower for distillation, thereby improving the purity of the fatty primary amine. The purity of the fatty primary amine after purification by the distillation tower is ≥99%.

[0013] Preferably, the fatty acid is one of lauric acid, palmitic acid and stearic acid.

[0014] Preferably, the catalyst is skeleton nickel.

[0015] Preferably: a metal wire mesh structured packing is arranged in the reactor.

[0016] Preferably, the reactor is connected to an ammonia circulation pipe, the ammonia circulation pipe is connected to an external ammonia source, and a valve is installed on the ammonia circulation pipe.

[0017] Preferably, the size of the ammonia circulation pipe is DN150.

[0018] Preferably, when preparing fatty nitrile, the total reaction time in the reactor, the dehydration tower and the gas phase reaction tower is controlled within 9 hours.

[0019] Preferably, the reaction temperature in the reactor is controlled at 300°C.

[0020] Preferably, the temperature in the hydrogenation reactor is 120° C. and the pressure is 2 MPa.

[0021] Preferably: the hydrogenation reactor is equipped with a mixing mechanism extending into the interior thereof, the mixing mechanism comprising: a circulation pump, an air inlet pipe, an air outlet pipe, a hollow rotating pipe, a diverter pipe, an air outlet hole, a stirring blade, a motor, a first gear and a second gear, the circulation pump is installed on the hydrogenation reactor, the air inlet end of the circulation pump is equipped with an air inlet pipe extending into the hydrogenation reactor, the air outlet end of the circulation pump is equipped with an air outlet pipe inserted into the hydrogenation reactor, the air outlet pipe is fixed to the hydrogenation reactor, the hollow rotating pipe is rotatably connected to the hydrogenation reactor, the bottom of the air outlet pipe is inserted into the hollow rotating pipe, the hollow rotating pipe is rotatably connected to the air outlet pipe, a plurality of diverter pipes are installed on the hollow rotating pipe, each of the diverter pipes is provided with a plurality of air outlet holes, a plurality of stirring blades are fixed on the hollow rotating pipe, the motor is fixed on the ground, a first gear is installed on the output shaft of the motor, and a second gear meshing with the first gear is installed on one side of the first gear.

[0022] The beneficial effects of the present invention are as follows: the preparation method for high-quality primary amine production, when used, first adds raw materials into a reactor to generate fatty acid ammonium salt, then dehydrates the fatty acid ammonium salt to obtain fatty nitrile, a metal wire mesh structured filler is provided in the reactor, and the metal wire mesh structured filler mist is entrained to improve the nitrile yield, and the temperature during the reaction is controlled at 300°C, which can reduce energy consumption and save energy, and then, the fatty nitrile is added into a hydrogenation reactor to react to obtain fatty primary amine, and the temperature during the reaction is controlled to 120°C and the pressure is 2MPa, thereby reducing energy consumption and improving the purity of the fatty primary amine. In summary, the present invention reduces the temperature and pressure of the reaction, saves energy, and can improve the generation rate of fatty primary amine, with higher economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of the present invention.

[0024] Figure 2 It is a partial structural diagram of the present invention. Figure 1 .

[0025] Figure 3 For the present invention Figure 2 Interior view of.

[0026] Figure 4 It is a partial structural diagram of the present invention. Figure 2 .

[0027] Legend:

[0028] 1. Hydrogenation reactor; 101. Hydrogen pipe; 102. Valve; 2. Mixing mechanism; 201. Circulation pump; 202. Air inlet pipe; 203. Air outlet pipe; 204. Hollow rotating tube; 205. Diverter pipe; 206. Air outlet hole; 207. Stirring blade; 208. Motor; 209. First gear; 210. Second gear. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Specific examples are given below.

[0031] Example 1

[0032] See also Figure 1 In an embodiment of the present invention, a preparation method for producing high-quality primary amines comprises the following steps:

[0033] Step 1, preparation of raw materials: select appropriate amounts of fatty acid, ammonia, hydrogen and catalyst according to demand, the fatty acid is one of lauric acid, palmitic acid and stearic acid, ammonia is used to provide nitrogen element in the reaction process, the catalyst is skeleton nickel, skeleton nickel is a solid heterogeneous catalyst composed of fine nickel-aluminum alloy grains with a porous structure, and can be used for catalytic hydrogenation, desulfurization and other reactions;

[0034] Step 2, preparation of fatty nitrile: adding fatty acid and ammonia into a reactor to react to generate fatty acid ammonium salt, controlling the reaction temperature in the reactor at 280-320° C. through a heat exchanger, and then transferring the fatty acid ammonium salt of the catalyst to a dehydration tower for dehydration to generate fatty nitrile;

[0035] Step 3, purification of fatty nitrile: the fatty nitrile obtained in step 2 is transferred to a gas phase reaction tower for further reaction to generate fatty nitrile, thereby improving the purity of the fatty nitrile;

[0036] Step 4: Generation of fatty primary amines: Add the fatty nitrile obtained in step 3 to a hydrogenation reactor, and then add hydrogen and a catalyst to the hydrogenation reactor, so that the fatty nitrile and hydrogen generate fatty primary amines under the action of the catalyst. The temperature in the hydrogenation reactor is 100-150° C. and the pressure is 1-3 MPa.

[0037] Step 5: Recovery of the catalyst: Add the product obtained in step 4 into a catalyst filtering device, and filter and recover the catalyst therein;

[0038] Step 6: Purification: The product filtered in step 5 is added into a distillation tower for distillation, thereby improving the purity of the fatty primary amine. The purity of the fatty primary amine after purification by the distillation tower is ≥99%.

[0039] The reactor is provided with a metal wire mesh structured filler, and the mist entrainment by the metal wire mesh structured filler can improve the yield of nitrile production.

[0040] The reactor is connected to an ammonia circulation pipe, which is connected to an external ammonia source. A valve is installed on the ammonia circulation pipe to control the delivery of ammonia. The ammonia is delivered to the reactor through the ammonia circulation pipe. The size of the ammonia circulation pipe is DN150. By increasing the ammonia circulation volume, the nitrile production reaction time is shortened.

[0041] When preparing fatty nitrile, the total reaction time in the reactor, the dehydration tower and the gas phase reaction tower is controlled within 9 hours.

[0042] Example 2

[0043] The reaction temperature in the reactor was controlled at 300°C, the temperature in the hydrogenation reactor was 120°C, and the pressure was 2MPa.

[0044] Example 3

[0045] See also Figure 2-4The top of the hydrogenation reactor 1 is provided with a hydrogen pipe 101, a valve 102 is installed on the hydrogen pipe 101, the hydrogen pipe 101 is connected to an external hydrogen source, and a mixing mechanism 2 extending to the inside of the hydrogenation reactor 1 is installed, and the mixing mechanism 2 includes: a circulation pump 201, an air inlet pipe 202, an air outlet pipe 203, a hollow rotating pipe 204, a diverter pipe 205, an air outlet 206, a stirring blade 207, a motor 208, a first gear 209 and a second gear 210. The circulation pump 201 is installed on the hydrogenation reactor The circulating pump 201 is mounted on the hydrogenation reactor 1, and the inlet end of the circulating pump 201 is equipped with an inlet pipe 202 extending into the hydrogenation reactor 1, and the outlet end of the circulating pump 201 is equipped with an outlet pipe 203 inserted into the hydrogenation reactor 1, the outlet pipe 203 is fixed to the hydrogenation reactor 1, and the hollow rotating pipe 204 is rotatably connected to the hydrogenation reactor 1, and the bottom of the outlet pipe 203 is inserted into the hollow rotating pipe 204, and the hollow rotating pipe 204 is rotatably connected to the outlet pipe 203, and a plurality of shunt pipes 205 are installed on the hollow rotating pipe 204, and each shunt pipe 205 is connected to the hydrogenation reactor 1. The tube 205 is provided with a plurality of air outlet holes 206, a plurality of stirring blades 207 are fixed on the hollow rotating tube 204, a motor 208 is fixed on the ground, a first gear 209 is installed on the output shaft of the motor 208, and a second gear 210 meshing with the first gear 209 is installed on one side of the first gear 209. When in use, the fatty nitrile (liquid), hydrogen and catalyst are added into the hydrogenation reactor 1, and then the hydrogen in the hydrogenation reactor 1 is extracted by the circulation pump 201 and transported to the hollow rotating tube 204, and then the hollow rotating tube 204 is used to transfer the hydrogen to the hydrogenation reactor 1. The rotating tube 204 transports hydrogen to multiple branch tubes 205, and multiple air outlets 206 transport hydrogen to various places in the fatty nitrile, so that the contact between hydrogen and the fatty nitrile is more complete. At the same time, the motor 208 drives the first gear 209 and the second gear 210 to rotate, and the second gear 210 drives the hollow rotating tube 204, the branch tube 205, and the stirring blade 207 to rotate. The stirring blade 207 stirs and mixes the hydrogen and the fatty nitrile, so that the hydrogen and the fatty nitrile are fully in contact, thereby improving the reaction efficiency.

[0046] Working principle: When using the preparation method for the production of high-quality primary amines, the raw materials are first added into a reactor to generate fatty acid ammonium salts, and then the fatty acid ammonium salts are dehydrated to obtain fatty nitrile. The reactor is provided with a metal wire mesh structured filler, and the mist entrainment of the metal wire mesh structured filler can improve the nitrile yield. The temperature during the reaction is controlled at 300°C, which can reduce energy consumption and save energy. Then, the fatty nitrile is added into a hydrogenation reactor to react to obtain fatty primary amines. The temperature during the reaction is controlled at 120°C and the pressure is 2MPa, thereby reducing energy consumption and improving the purity of the fatty primary amines.

[0047] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A preparation method for producing high-quality primary amines, characterized in that: The following steps are involved: Step 1: Preparation of raw materials: Select appropriate amounts of fatty acid, ammonia, hydrogen and catalyst according to demand; Step 2, preparation of fatty nitrile: adding fatty acid and ammonia into a reactor to react to generate fatty acid ammonium salt, controlling the reaction temperature in the reactor at 280-320° C. through a heat exchanger, and then transferring the fatty acid ammonium salt of the catalyst to a dehydration tower for dehydration to generate fatty nitrile; Step 3, purification of fatty nitrile: the fatty nitrile obtained in step 2 is transferred to a gas phase reaction tower for further reaction to generate fatty nitrile, thereby improving the purity of the fatty nitrile; Step 4: Generation of fatty primary amines: Add the fatty nitrile obtained in step 3 to a hydrogenation reactor (1), and then add hydrogen and a catalyst to the hydrogenation reactor, so that the fatty nitrile and the hydrogen generate fatty primary amines under the action of the catalyst. The temperature in the hydrogenation reactor is 100-150° C. and the pressure is 1-3 MPa. Step 5: Recovery of the catalyst: Add the product obtained in step 4 into a catalyst filtering device, and filter and recover the catalyst therein; Step 6: Purification: The product filtered in step 5 is added into a distillation tower for distillation, thereby improving the purity of the fatty primary amine. The purity of the fatty primary amine after purification by the distillation tower is ≥99%.

2. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The fatty acid is one of lauric acid, palmitic acid and stearic acid.

3. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The catalyst is skeleton nickel.

4. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The reactor is provided with a metal wire mesh structured packing.

5. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The reactor is connected to an ammonia circulation pipe, the ammonia circulation pipe is connected to an external ammonia source, and a valve is installed on the ammonia circulation pipe.

6. The preparation method for producing high-quality primary amines according to claim 5, characterized in that: The size of the ammonia circulation pipe is DN150.

7. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: When preparing fatty nitrile, the total reaction time in the reactor, the dehydration tower and the gas phase reaction tower is controlled within 9 hours.

8. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The reaction temperature in the reactor is controlled at 300°C.

9. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The temperature in the hydrogenation reactor is 120° C. and the pressure is 2 MPa.

10. The preparation method for producing high-quality primary amines according to claim 1, characterized in that: The hydrogenation reactor (1) is provided with a mixing mechanism (2) extending into the interior thereof, the mixing mechanism (2) comprising: a circulation pump (201), an air inlet pipe (202), an air outlet pipe (203), a hollow rotating pipe (204), a flow dividing pipe (205), an air outlet hole (206), a stirring blade (207), a motor (208), a first gear (209) and a second gear (210), the circulation pump (201) being installed on the hydrogenation reactor (1), the air inlet end of the circulation pump (201) being provided with an air inlet pipe (202) extending into the hydrogenation reactor (1), the air outlet end of the circulation pump (201) being provided with an air outlet pipe (203) inserted into the hydrogenation reactor (1), the air outlet pipe (203) being connected to the hydrogenation reactor (1) and the air outlet pipe (203) being connected to the hydrogenation reactor (1). The reactor (1) is fixed, the hollow rotating tube (204) is rotatably connected to the hydrogenation reactor (1), the bottom of the outlet pipe (203) is inserted into the hollow rotating tube (204), the hollow rotating tube (204) is rotatably connected to the outlet pipe (203), a plurality of branch pipes (205) are installed on the hollow rotating tube (204), each of the branch pipes (205) is provided with a plurality of outlet holes (206), a plurality of stirring blades (207) are fixed on the hollow rotating tube (204), the motor (208) is fixed on the ground, a first gear (209) is installed on the output shaft of the motor (208), and a second gear (210) meshing with the first gear (209) is installed on one side of the first gear (209).

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