Intermittent production method of triethyl aluminum

Abstract

The invention provides an intermittent production method of triethyl aluminum. The method comprises the following steps: mixing triethyl aluminum, aluminum powder and iodine vapor; adding hydrogen for hydrogenation reaction; and carrying out acetylation reaction with ethylene to prepare the triethyl aluminum. The iodine vapor is adopted to activate the aluminum powder, the initiation time of the aluminum powder to the reaction is shortened, the hydrogenation reaction time is shortened, and therefore the whole reaction speed is increased; meanwhile, by adopting the method disclosed by the invention, the iodine vapor is easy to remove, the iodine vapor can be recycled, and the production cost can be reduced while the reaction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical catalysts and relates to an intermittent production method of triethylaluminum. Background Art

[0002] As a co-catalyst component in the Ziegler-Natta catalyst system, triethylaluminum plays a crucial role in the synthesis and development of polyolefins. Triethylaluminum production methods are primarily divided into continuous and batch processes. The batch process primarily involves two steps: hydrogenation and ethylation. The first step, hydrogenation, involves a three-phase reaction of hydrogen, triethylaluminum seed, and aluminum powder. Under high-pressure hydrogen pressure of 10 MPa and a high temperature of 125-132°C, sufficient hydrogen is dissolved in the triethylaluminum. The second step, ethylation, involves an addition reaction of the hydrogenation reaction product (diethylaluminum hydride) with ethylene. The ethylene feed must be controlled during the reaction.

[0003] As a chemical raw material, the oxide layer on the surface of aluminum powder can ensure its safety during transportation, storage and use, but it will slow down the reaction speed and prolong the reaction cycle.

[0004] Currently, researchers are increasing the reaction rate by introducing additional activators. For example, Chinese invention patent CN102584879B discloses a method for preparing triethylaluminum. This method uses a trace amount of chromium powder to pre-activate aluminum powder before using it in the reaction to improve production efficiency. This process is complex and time-consuming. Furthermore, even trace amounts of residual water or alcohol introduced during this activation process can react with the triethylaluminum mother liquor or product, causing combustion and explosion, impacting production safety. Furthermore, the chromium powder used is difficult to remove, affecting product quality and potentially causing heavy metal pollution in the environment.

[0005] Therefore, it is urgent to propose a method that can improve the production efficiency of triethylaluminum. Summary of the Invention

[0006] In view of the above technical problems, the present invention provides a batch production method of triethylaluminum, which has significantly improved production efficiency.

[0007] Specifically, the present invention proposes the following technical solutions:

[0008] A batch production method of triethyl aluminum, comprising:

[0009] 1) Mixing triethylaluminum, aluminum powder and iodine vapor;

[0010] 2) adding hydrogen to carry out hydrogenation reaction;

[0011] 3) Acetylation reaction is then carried out with ethylene to prepare triethylaluminum.

[0012] According to an embodiment of the present invention, in step 1), the mass ratio of the aluminum powder to triethylaluminum is 1:(6-25), preferably 1:(10-20).

[0013] According to an embodiment of the present invention, in step 1), the mass volume ratio of aluminum powder to iodine vapor is 1 g:(0.1-3) L, preferably 1 g:(0.5-1.5) L.

[0014] According to an embodiment of the present invention, in step 2), the pressure of the hydrogenation reaction is 3-14 MPa, preferably 5-12 MPa.

[0015] According to an embodiment of the present invention, in step 2), the hydrogenation reaction time is 4-7 hours.

[0016] According to an embodiment of the present invention, in step 2), the temperature of the hydrogenation reaction is 110-132°C.

[0017] According to an embodiment of the present invention, in step 2), after the hydrogenation reaction is completed, the reactor is cooled and the unreacted hydrogen and iodine vapor in the reactor are collected and used for the next hydrogenation reaction cycle.

[0018] According to an embodiment of the present invention, in step 3), the pressure of the ethylation reaction is 1-2 MPa.

[0019] According to an embodiment of the present invention, in step 3), the ethylation reaction time is 4-5 hours.

[0020] According to an embodiment of the present invention, in step 3), the temperature of the ethylation reaction is 50-70°C.

[0021] Beneficial effects of the present invention:

[0022] The present invention uses iodine vapor to activate aluminum powder, thereby reducing the initiation time of the aluminum powder for the reaction and shortening the time of the hydrogenation reaction, thereby improving the speed of the entire reaction; at the same time, the method of the present invention can easily remove the iodine vapor and can also recycle and reuse the iodine vapor, thereby improving the reaction efficiency and reducing the production cost. DETAILED DESCRIPTION

[0023] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0024] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0025] Example 1

[0026] A batch production method of triethyl aluminum, comprising:

[0027] (1) Expel the air from the reactor and mix 1 g of triethylaluminum, 14 g of aluminum powder, and 1 L of iodine vapor;

[0028] (2) hydrogen was continuously added at 115°C and 8 MPa for 5 h;

[0029] (3) After the hydrogenation reaction is completed, the reactor is cooled to room temperature, and the unreacted hydrogen and iodine vapor in the reactor are collected and used for the next hydrogenation reaction cycle;

[0030] (4) Ethylene was introduced into the reactor to carry out acetylation reaction, and the pressure in the reactor was controlled to be constant at 1.5 MPa, the temperature was controlled to be 65° C., and the acetylation reaction time was controlled to be 4 h, thereby obtaining the crude triethylaluminum product.

[0031] Example 2

[0032] A batch production method of triethyl aluminum, comprising:

[0033] (1) Expel the air from the reactor and mix 1 g of triethylaluminum, 16 g of aluminum powder, and 1.2 L of iodine vapor;

[0034] (2) Hydrogen was continuously added at 110°C and 9 MPa for 4.5 h;

[0035] (3) After the hydrogenation reaction is completed, the reactor is cooled to room temperature, and the unreacted hydrogen and iodine vapor in the reactor are collected and used for the next hydrogenation reaction cycle;

[0036] (4) Ethylene was introduced into the reactor to carry out acetylation reaction, and the pressure in the reactor was controlled to be constant at 1.4 MPa, the temperature was controlled to be 60° C., and the acetylation reaction time was controlled to be 5 h, thereby obtaining the crude triethylaluminum product.

[0037] Example 3

[0038] A batch production method of triethyl aluminum, comprising:

[0039] (1) Expel the air from the reactor and mix 1 g of triethylaluminum, 20 g of aluminum powder, and 1.5 L of iodine vapor;

[0040] (2) hydrogen was continuously added at 110°C and 10 MPa for 4 h;

[0041] (3) After the hydrogenation reaction is completed, the reactor is cooled to room temperature, and the unreacted hydrogen and iodine vapor in the reactor are collected and used for the next hydrogenation reaction cycle;

[0042] (4) Ethylene was introduced into the reactor to carry out acetylation reaction, and the pressure in the reactor was controlled to be constant at 2 MPa, the temperature was controlled to be 50° C., and the acetylation reaction time was controlled to be 4 h, thereby obtaining the crude triethylaluminum product.

[0043] The above is an exemplary description of the embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A batch production method of triethyl aluminum, characterized in that, The method comprises: 1) Mixing triethylaluminum, aluminum powder and iodine vapor; 2) adding hydrogen to carry out hydrogenation reaction; 3) Acetylation reaction is then carried out with ethylene to prepare triethylaluminum.

2. The batch production method according to claim 1, characterized in that In step 1), the mass ratio of the aluminum powder to triethylaluminum is 1:(6-25).

3. The batch production method according to claim 1 or 2, characterized in that: In step 1), the mass volume ratio of aluminum powder to iodine vapor is 1g:(0.1-3)L.

4. The intermittent production method according to any one of claims 1 to 3, characterized in that: In step 2), the pressure of the hydrogenation reaction is 3-14 MPa.

5. The intermittent production method according to any one of claims 1 to 4, characterized in that: In step 2), the hydrogenation reaction time is 4-7 hours.

6. The intermittent production method according to any one of claims 1 to 5, characterized in that: In step 2), the temperature of the hydrogenation reaction is 110-132°C.

7. The intermittent production method according to any one of claims 1 to 6, characterized in that: In step 2), after the hydrogenation reaction is completed, the reactor is cooled and the unreacted hydrogen and iodine vapor in the reactor are collected and used for the next hydrogenation reaction cycle.