CN115872838A - Method for preparing high-purity aluminum isopropoxide by continuous method - Google Patents

Abstract

The invention belongs to the field of synthesis of basic metal organic chemical materials, and discloses a method for preparing high-purity aluminum isopropoxide by a continuous method. The method disclosed by the invention can be used for preparing high-purity aluminum isopropoxide by a continuous method, effectively solving the problems of low production efficiency, difficulty in purity improvement and high production cost existing in an intermittent reaction production process, improving the production efficiency, ensuring the product purity, the productivity and the like by virtue of the unique advantages of continuous production while carrying out mass production, fully meeting the market demand and having good industrial prospect.

Description

A kind of continuous method prepares the method for high-purity aluminum isopropoxide

technical field

The invention belongs to the field of synthesis of basic metal organic chemical materials, in particular to a method for preparing high-purity aluminum isopropoxide, in particular to a continuous method for preparing high-purity aluminum isopropoxide.

Background technique

Due to its stable properties and unique porous structure, alumina has a wide range of applications and demands in many fields. However, with the development of science and technology, higher requirements are placed on the purity of alumina. The internationally recognized high-purity alumina preparation process is mainly achieved by hydrolysis of aluminum alkoxide followed by roasting, and the most widely used method is the hydrolysis of aluminum isopropoxide. The basic principle of preparing high-purity alumina from aluminum isopropoxide is that aluminum isopropoxide is hydrolyzed to obtain water and alumina, and high-purity alumina powders with different crystal structures can be obtained under a specific roasting environment. Therefore, for high-purity alumina Therefore, it is of great significance to improve the purity of raw material aluminum isopropoxide. Aluminum isopropoxide is also a classic industrial intermediate material. It is often used as a precursor material for dehydrating agents, waterproofing agents, reducing agents and catalysts. The purity requirements of aluminum alkoxide are getting higher and higher, and the efficient production of aluminum isopropoxide with a purity of 5N and above (mass purity of aluminum isopropoxide ≥ 99.999%) has become a key research direction of chemical scientists.

At present, the commonly used initiators in the production of aluminum isopropoxide include aluminum isopropoxide, aluminum chloride, mercuric chloride, iodine, and copper chloride. In the patent CN1478767, a method for preparing aluminum isopropoxide is disclosed, adding metal aluminum and catalytic promoters into the synthesis reaction kettle, wherein the adding process of metal aluminum is divided into multiple additions, and the amount added in batches is 20wt% of the whole -50wt%, the addition of catalytic promoter accounts for 70wt%-80wt% of all materials, then according to a constant speed, add isopropanol in the synthesis reactor, isopropanol accounts for 20wt%-30wt% of the overall material, reflux condenser The exhaust gas temperature is between 27°C and 29°C, and the inlet gas temperature is between 72°C and 75°C.

In the patent CN 102992959, a method for preparing aluminum isopropoxide by using hydrous isopropanol is disclosed, which requires that the water content in the isopropanol used as the raw material liquid be higher than 0.3wt%. The main process includes: adding aluminum isopropoxide In isopropanol, heat and stir to fully dissolve, then add metal aluminum and catalyst, and heat to 82°C-100°C, the evaporated isopropanol returns to the reaction device through the reflux device, no need to add in the middle of the process, and put it into the reaction kettle The aluminum flakes are completely consumed and the reaction ends. Atmospheric distillation is then carried out, and the isopropanol in the reaction kettle is recovered, and recycled after treatment, and the distilled product can be dried to obtain dry aluminum isopropoxide powder after subsequent drying.

At present, the production method of aluminum isopropoxide is mostly an intermittent process carried out in an atmospheric pressure kettle, which has low production efficiency and prolongs the entire product production cycle. In addition, catalysts need to be introduced, which increases the source of product impurities. It is also necessary to carefully handle the escape of by-product hydrogen and control the production volume, etc., for the subsequent purification of aluminum isopropoxide, safety hazard investigation and efficient production. It is difficult to meet the needs of the market. For the current defects of the batch production process, it is necessary to further improve it, or adopt a continuous production process to further improve the production efficiency and purity of the product.

Contents of the invention

In view of this, for the existing defects of the batch reaction, the purpose of the present invention is to provide a continuous method for preparing high-purity aluminum isopropoxide method, at least partially solve the problems in the prior art.

For realizing the purpose of the present invention, the present invention adopts following technical scheme:

A method for preparing high-purity aluminum isopropoxide by a continuous method, packing elemental metal into a fixed-bed reactor, rinsing the bed of the fixed-bed reactor with an isopropanol solution containing an initiator, and then pouring the isopropanol continuously Inject into a fixed-bed reactor, pressurize and heat to react, collect the reaction product, distill under reduced pressure and dry to obtain high-purity aluminum isopropoxide.

Preferably, the method further includes a step of removing water from the isopropanol until the water content of the isopropanol is ≤0.5wt% before injecting the isopropanol into the fixed-bed reactor.

As a preference, the isopropanol water removal in the method is to fully mix the quantitative molecular sieve and the isopropanol solution, and let it stand for adsorption treatment.

Preferably, in the method, the molecular sieve model is at least one of 3A, 4A, and 5A; the molecular sieve diameter specification is 0.5mm-3.0mm; the molecular sieve dewatering time is 4h-24h.

Preferably, the metal aluminum purity in the described method is ≥99.7%, and the purity of the isopropanol is ≥99.0%. In the described method, the initiator is aluminum isopropoxide, copper chloride, chloride At least one of aluminum, mercuric chloride and iodine; the content of the initiator is 0.05wt%-0.1wt%.

Preferably, in the method, the pressure and heating for the reaction is carried out at a reaction pressure of 0.5Mpa-10Mpa, a reaction temperature of 80°C-200°C, and a reaction time of 4h-12h.

As a preference, the flow space velocity of the isopropanol in the method is 5h ^-1 to 12h ^-1 .

Preferably, in the method, the reaction temperature of the vacuum distillation is 80° C. to 150° C., and the pressure is 0.01M to 0.1Mpa.

As a preference, the drying temperature in the method is 60°C-150°C, and the drying time is 6h-24h.

It can be seen from the above technical scheme that the present invention provides a continuous method for preparing high-purity aluminum isopropoxide, wherein the elemental metal is packed into a fixed-bed reactor, and the fixed-bed reaction is rinsed with an isopropanol solution containing an initiator. Then, isopropanol is continuously injected into the fixed bed reactor, pressurized and heated for reaction, and the reaction product is collected, evaporated under reduced pressure and then dried to obtain high-purity aluminum isopropoxide. The method of the present invention prepares high-purity aluminum isopropoxide through a continuous method, which effectively improves the problems of low production efficiency, difficulty in improving purity and high production cost in the batch reaction production process, improves production efficiency, and can be used in mass production At the same time, it can also rely on the unique advantages of continuous production to ensure product purity and production capacity, which can fully meet market demand and has a good industrialization prospect.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is the reaction schematic diagram of preparing high-purity aluminum isopropoxide by the continuous method of the present invention.

Detailed ways

The invention discloses a continuous method for preparing high-purity aluminum isopropoxide. Elemental metal is loaded into a fixed-bed reactor, and the bed of the fixed-bed reactor is rinsed with an isopropanol solution containing an initiator, and then the Isopropanol is continuously injected into a fixed-bed reactor, pressurized and heated for reaction, and the reaction product is collected, evaporated under reduced pressure and then dried to obtain high-purity aluminum isopropoxide.

The method of the present invention uses isopropanol and elemental metal aluminum of ordinary purity as raw materials, uses the isopropanol solution compounded by different initiators to rinse the reactant bed as the reaction starting catalyst, and then according to the constant feed flow rate, the The isopropanol solution is injected into the fixed bed reactor, and the aluminum alkoxide reaction can be self-catalyzed and continuously synthesized, and the reaction product can be obtained through subsequent distillation and drying processes to obtain high-purity aluminum isopropoxide powder.

In the method of the present invention, the fixed bed reactor can withstand a pressure of 0.5Mpa-10.0Mpa, and the material of the reactor can withstand acid and alkali.

The isopropanol water removal is to fully mix the quantitative molecular sieve and the isopropanol solution, and let it stand for adsorption treatment.

In the method of the present invention, the purity of the used reaction raw material isopropanol is more than or equal to 99.0%, and the diameter of the used dehydration molecular sieve is 0.5mm-3.0mm, preferably 4A grade molecular sieve, and the diameter specification is preferably 0.5mm-1.0mm; the molecular sieve dehydration treatment time is preferably 4h-48h, preferably 6h-24h, detect the water content of isopropanol ≤0.5wt%, preferably ≤0.15wt%; elemental metal aluminum purity ≥99.7%, preferably ≥99.9%, metal aluminum can be processed into ingots, wires, strips, There is no limit to blocks, etc., as long as the filling requirements and feeding requirements of the fixed bed reactor are met.

In the method of the present invention, the reaction initiator is obtained by mixing one or more of aluminum isopropoxide, aluminum chloride, mercuric chloride, iodine, copper chloride, etc. with isopropanol, and the concentration of the compound solution is 0.05wt%. -0.1wt%, preferably aluminum isopropoxide, 0.08wt%, fully eluting the bed metal aluminum raw material. The initiator solution can be recycled.

In the method of the present invention, the processed elemental metal aluminum (ingot, wire, bar, block, etc. is not limited) is loaded into the fixed bed reactor, and the feeding port is set, and the flow space velocity ratio of the feed pump is 5.0-12.0 h ^-1 , the reaction temperature is 80°C-200°C, the reaction pressure is 0.5Mpa-10.0Mpa, the reaction time is 4h-12h, the preferred space velocity ratio is 8.0-10.0h ^-1 , the reaction temperature is 120°C-150°C, The reaction pressure is 1.5Mpa-3.0Mpa, and the reaction time is 8h-10h.

In the method of the present invention, the aluminum isopropoxide product obtained by the continuous bed layer reaction is collected into the distillation tower, the distillation temperature is 85°C-180°C, the operating pressure is reduced pressure, the pressure range is: 0.01Mpa to 0.1Mpa, and the preferred distillation temperature is 135°C-155°C, pressure range: 0.05Mpa to 0.08Mpa, drying temperature 60°C-150°C, drying time 6h-24h, preferably 120°C/12h.

In order to further understand the present invention, the present invention will be described in detail below in conjunction with the examples. It should be noted that, in the case of no conflict, the following embodiments and the features in the embodiments can be combined with each other; and, based on the embodiments in the present disclosure, those of ordinary skill in the art obtained without creative work All other embodiments belong to the protection scope of the present disclosure.

Embodiment 1,

Mix 10g of 4A molecular sieve with 200ml of isopropanol solution and let it stand to remove water. After 12 hours, it is detected that the water content is 0.15wt%, and it is filtered for later use. Process 30 g of aluminum strips with a purity of 99.9% into aluminum pellets with a diameter of about 0.5 cm, and fill them into a fixed-bed reactor.

Configure 20ml, 0.1wt% aluminum isopropoxide/isopropanol solution, fully rinse the aluminum particles in the bed, close the reactor, raise the temperature and pressurize for reaction, the reaction temperature is 150°C, the reaction pressure is 1.5Mpa, and the flow rate and air velocity ratio of the feed pump is 8.0h ^-1 , the reaction time is 8h, and the reaction product is collected at the outlet after the reaction.

The reaction product was purified by distillation at 150°C and 0.1Mpa under reduced pressure, and then placed in a drying oven at 120°C for 24 hours to obtain dry aluminum isopropoxide powder. The reaction conversion rate and product purity are shown in Table 1.

Embodiment 2,

Mix 10g of 4A molecular sieve with 300ml of isopropanol solution and let it stand to remove water. After 12 hours, it is detected that the water content is 0.10wt%, and it is filtered for later use. Process 50 g of aluminum strips with a purity of 99.9% into aluminum particles with a diameter of about 1.0 cm, and fill them into a fixed-bed reactor.

Configure 30ml, 0.05wt% aluminum isopropoxide/isopropanol solution, fully rinse the aluminum particles in the bed, close the reactor, heat up and pressurize to react, the reaction temperature is 180°C, the reaction pressure is 3.0Mpa, and the flow space velocity of the feed pump The ratio is 5.0h ^-1 , the reaction time is 8h, and the reaction product is collected at the outlet after the reaction.

The reaction product was purified by distillation at 150°C and 0.08Mpa under reduced pressure, and then placed in a drying oven at 120°C for 24 hours to obtain dry aluminum isopropoxide powder. The reaction conversion rate and product purity are shown in Table 1 .

Embodiment 3,

Mix 10g of 4A molecular sieve with 200ml of isopropanol solution and let it stand to remove water. After 12 hours, it is detected that the water content is 0.15wt%, and it is filtered for later use. Process 30g of aluminum strips with a purity of 99.9% into aluminum pellets with a diameter of about 0.5cm, and fill them into a fixed-bed reactor.

Configure 20ml, 0.1wt% aluminum isopropoxide/isopropanol solution, fully rinse the aluminum particles in the bed, close the reactor, heat up and pressurize to react, the reaction temperature is 120°C, the reaction pressure is 2.0Mpa, and the flow space velocity of the feed pump The ratio is 8.0h ^-1 , the reaction time is 8h, and the reaction product is collected at the outlet after the reaction.

The reaction product was distilled and purified at 140°C and 0.1Mpa under reduced pressure, and then placed in a drying oven at 120°C for 24 hours to obtain dry aluminum isopropoxide powder. The reaction conversion rate and product purity are shown in Table 1 .

Embodiment 4,

Mix 10g of 4A molecular sieve with 200ml of isopropanol solution and let it stand to remove water. After 12 hours, it is detected that the water content is 0.10wt%, and it is filtered for later use. Process 30g of 99.9% pure aluminum strips into aluminum pellets with a diameter of about 0.8cm, and fill them into a fixed-bed reactor.

Configure 20ml, 0.05wt% aluminum isopropoxide/isopropanol solution, fully rinse the aluminum particles in the bed, close the reactor, heat up and pressurize to react, the reaction temperature is 120°C, the reaction pressure is 1.0Mpa, and the flow rate of the feed pump is empty. The ratio is 12.0h ^-1 , the reaction time is 8h, and the reaction product is collected at the outlet after the reaction.

The reaction product was purified by distillation at 155°C and 0.08Mpa under reduced pressure, and then placed in a drying oven at 120°C for 24 hours to obtain dry aluminum isopropoxide powder. The reaction conversion rate and product purity are shown in Table 1 .

Comparative example 1,

The high-purity aluminum isopropoxide material was prepared according to the method of Example 1, except that the water content of the isopropanol solution was 2.0 wt%, and other conditions were the same, and the reaction conversion rate and product purity were shown in Table 1.

Comparative example 2,

The high-purity aluminum isopropoxide material was prepared according to the method of Example 2, the difference being that the concentration of the reaction initiator aluminum isopropoxide/isopropanol solution was 0.02wt%, and other conditions were the same, and the reaction efficiency and product purity were shown in Table 1.

Comparative example 3,

The high-purity aluminum isopropoxide material was prepared according to the method of Example 3, the difference being that the purity of the reaction raw material elemental metal aluminum was 95%, and other conditions were the same, and the reaction conversion rate and product purity were shown in Table 1.

Comparative example 4,

The high-purity aluminum isopropoxide material was prepared according to the method of Example 4, with the difference that the flow rate ratio of the feed pump was 3.0 h ⁻¹ and other conditions were the same, and the reaction conversion rate and product purity were shown in Table 1.

Table 1 Conversion rate and product purity table of aluminum isopropoxide

Sample serial number Conversion rate Product purity Example 1 100% 99.993% Example 2 100% 99.995% Example 3 100% 99.990% Example 4 100% 99.992% Comparative example 1 0% / Comparative example 2 98% 99.992% Comparative example 3 100% 99.93% Comparative example 4 90% 99.991%

As can be seen from the results in Table 1, the reaction conversions of Examples 1-4 are all 100%, and the product purity is all ≥99.990%. And comparative example 1 raw material water content is too high, and reaction does not trigger; Comparative example 2 initiator concentration is too low, and reaction initiation time prolongs, and does not affect product purity; Comparative example 3 low-purity aluminum raw material can obtain aluminum isopropoxide product more than 3N purity; Comparative example 4 has a low space velocity ratio, which reduces the conversion rate and does not affect the product purity.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Anyone skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present invention. All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. A method for preparing high-purity aluminum isopropoxide by a continuous method is characterized in that a single metal is filled into a fixed bed reactor, an isopropanol solution containing an initiator is used for leaching a bed layer of the fixed bed reactor, then isopropanol is continuously injected into the fixed bed reactor to be pressurized and heated for reaction, a reaction product is collected, and the high-purity aluminum isopropoxide is obtained after reduced pressure distillation and drying.

2. The method of claim 1 further comprising the step of removing water from the isopropanol to a water content of 0.5 wt.% or less prior to injecting the isopropanol into the fixed bed reactor.

3. The method according to claim 2, wherein the isopropanol is dewatered by fully mixing a quantitative molecular sieve with an isopropanol solution and carrying out standing adsorption treatment.

4. The method of claim 3, wherein the molecular sieve type is at least one of 3A, 4A, 5A; the diameter specification of the molecular sieve is 0.5mm-3.0mm; the water removal time of the molecular sieve is 4-24 h.

5. The method of claim 1, wherein the metallic aluminum purity is greater than or equal to 99.7%, and the isopropanol purity is greater than or equal to 99.0%.

6. The method of claim 1, wherein the initiator is at least one of aluminum isopropoxide, copper chloride, aluminum chloride, mercuric chloride, iodine; the content of the initiator in the isopropanol solution containing the initiator is 0.05wt% -0.1wt%.

7. The method of claim 1, wherein the pressure heating is performed at a reaction pressure of 0.5Mpa to 10Mpa, a reaction temperature of 80 ℃ to 200 ℃, and a reaction time of 4h to 12h.

8. The method according to claim 1, wherein the flow space velocity of the isopropanol is 5h ^-1 ～12h ^-1 。

9. The method according to claim 1, wherein the reduced pressure distillation is carried out at a reaction temperature of 80 ℃ to 150 ℃ and a pressure of 0.01 to 0.1MPa.

10. The method according to claim 1, wherein the drying temperature is 60-150 ℃ and the drying time is 6-24 h.

Images