阅读说明：本技术 一种高纯度烷氧基铝的制备方法 (Preparation method of high-purity alkoxy aluminum ) 是由 李明哲 杨彦鹏 聂骥 于 2020-05-28 设计创作，主要内容包括：一种高纯度烷氧基铝的制备方法,包括在活化铝存在下,将高纯度铝和C-(3)～C-(6)的脂肪醇按1：3～5的摩尔比在不高于醇沸点的温度下反应,得到高纯度烷氧基铝,活化铝与高纯度铝的质量比为1～10％,所述的活化铝为将低纯度铝与C-(3)～C-(6)的脂肪醇按1：1.5～2.9的摩尔比在不高于醇沸点的温度下充分反应后剩余的铝,所述低纯度铝的纯度不大于99.90质量％,高纯度铝的纯度不小于99.99质量％。该法可有效缩短脂肪醇和金属铝反应的时间,且不引入金属铝所带杂质以外的其它杂质。(A process for preparing high-purity alkoxy aluminium includes such steps as mixing high-purity aluminium with C in the presence of activated aluminium 3 ～C 6 The fatty alcohol of (1): 3-5 mol ratio of the aluminum hydroxide and the alcohol to obtain high-purity alkoxy aluminum, wherein the mass ratio of the activated aluminum to the high-purity aluminum is 1-10%, and the activated aluminum is prepared by mixing low-purity aluminum and C 3 ～C 6 The fatty alcohol of (1): 1.5-2.9, wherein the purity of the low-purity aluminum is not more than 99.90 mass percent, and the purity of the high-purity aluminum is not less than 99.99 mass percent. The method can effectively shorten the reaction time of the fatty alcohol and the metallic aluminum, and does not introduce other impurities except the impurities carried by the metallic aluminum.)

1. A process for preparing high-purity alkoxy aluminium includes such steps as mixing high-purity aluminium with C in the presence of activated aluminium₃～C₆The fatty alcohol of (1): 3-5 mol ratio of the aluminum hydroxide and the alcohol to obtain high-purity alkoxy aluminum, wherein the mass ratio of the activated aluminum to the high-purity aluminum is 1-10%, and the activated aluminum is prepared by mixing low-purity aluminum and C₃～C₆The fatty alcohol of (1): 1.5 to 2.9 of aluminum remaining after the reaction at a temperature not higher than the boiling point of the alcohol,

the purity of the low-purity aluminum is not more than 99.90 mass%, and the purity of the high-purity aluminum is not less than 99.99 mass%.

2. The method according to claim 1, wherein the low purity aluminum has a purity of 99.00 to 99.90 mass%.

3. The method of claim 1, wherein the low purity aluminum is mixed with C₃～C₆The activated aluminum prepared after the reaction of the fatty alcohol is sealed and stored by inert gas before use.

4. The method of claim 1, wherein the low purity aluminum is mixed with C₃～C₆The fatty alcohol of (1): 2.1 to 2.9 in a molar ratio at a temperature not higher than the boiling point of the alcohol.

5. A method according to claim 1, characterized in that high-purity aluminium and C are mixed₃～C₆The fatty alcohol of (1): 3.2 to 4.5 mol ratio.

6. The method according to claim 1, wherein the mass ratio of the activated aluminum to the high purity aluminum is 2 to 9%.

7. The process of claim 1 wherein the reaction temperature is from 20 ℃ below the boiling point of the alcohol to the boiling point of the alcohol.

8. The method of claim 1, wherein the high-purity aluminum and the low-purity aluminum are aluminum blocks, aluminum beans, aluminum flakes, aluminum wires, or aluminum shavings.

Technical Field

The invention relates to a preparation method of high-purity alkoxy aluminum, in particular to a method for preparing high-purity alkoxy aluminum by using metal aluminum and fatty alcohol as raw materials.

Background

The high-purity alumina is usually ultrafine alumina powder with the purity of more than 4N grade, is an inorganic metal oxide which is insoluble in water and soluble in acid and alkali, has excellent physicochemical properties far exceeding those of common alumina, is widely applied to oil refining catalytic processes such as catalytic reforming, isomerization and hydrogenation as a raw material, and is also applied to the environmental protection fields such as automobile exhaust catalysts, water purifying agents and exhaust treatment. In recent years, with the vigorous development of the domestic mobile phone market and the wide use of new energy products, the application field of high-purity alumina is further expanded, and the application of the high-purity alumina in the emerging fields of sapphire preparation, antistatic agents, high-performance ceramics and the like is increasingly increased.

At present, many researches are carried out at home and abroad on the preparation method of high-purity aluminum oxide, and the methods mainly adopted include an improved Bayer method, a sol-gel method, an aluminum alkoxide hydrolysis method, an aluminum ammonium sulfate pyrolysis method, a hydrothermal synthesis method, an aluminum ammonium carbonate pyrolysis method and the like. The aluminum alkoxide hydrolysis method has the advantages that metal aluminum and fatty alcohol are used as raw materials, impurity ions are not introduced in the reaction process, the aluminum hydroxide powder can be further purified through reduced pressure distillation or recrystallization, and the purity of the obtained aluminum hydroxide powder is higher.

The main process for preparing high-purity alumina by the aluminum alkoxide hydrolysis method comprises the following steps: the method comprises the steps of synthesis of aluminum alkoxide, hydrolysis of aluminum alkoxide, post-treatment of aluminum hydroxide slurry, drying and the like. Since the last 50 s, people have conducted a great deal of research on the preparation process of aluminum alkoxide, mainly focusing on using a catalyst, and using metal aluminum and fatty alcohol as raw materials to directly react to generate aluminum alkoxide, wherein the common catalysts for the reaction include: HgCl₂，CuCl₂，FeCl₃，SnCl₄、BCl₃、AlCl₃Titanium halide or aluminum isopropoxide, and the like, and the catalytic effects achieved by different catalysts are different.

USP2579251 and USP2636865 disclose the use of HgCl₂、CuCl₂、FeCl₃、SnCl₄、B₂O₃And I₂Is used as a catalyst to catalyze the reaction of metallic aluminum and fatty alcohol to generate aluminum alkyl oxide. The above catalyst was added for the purpose of removing the oxide film on the surface of the metallic aluminum, but HgCl₂As a catalyst, mercury ions are introduced, which is not suitable for large-scale production; and other catalyst CuCl₂，FeCl₃，SnCl₄And BCl₃The catalytic efficiency is lower, and the yield of the aluminum alkoxide is lower.

CN104230662A discloses a method for using AlCl₃As catalyst, catalytic metal aluminium anda method for preparing high-purity aluminum isopropoxide by isopropanol reaction. The reaction catalyzed by the method is AlCl₃Firstly reacts with isopropanol to generate HCl so as to lead H in the solution to be⁺Increased solubility, H⁺And reacts with aluminum to form H₂And Al³⁺，Al³⁺Can react with isopropanol to generate aluminum isopropoxide and H⁺The reaction cycle is repeated. The isopropanol used in the method is added in two steps, firstly, the isopropanol is dehydrated by aluminum isopropoxide, and secondly, 5N aluminum isopropoxide, anhydrous aluminum trichloride and metallic aluminum are added into the isopropanol for reaction.

CN101935326A discloses a preparation method of alkoxy aluminum, which takes titanium halide as a catalyst to catalyze the reaction of metal aluminum and fatty alcohol, and the method has the advantages of lower reaction temperature, less side reaction and improved product yield, but the catalyst used in the method introduces new impurities, and has certain influence on the purity of alkoxy aluminum.

CN104355967A discloses a method for synthesizing aluminum isopropoxide in one step by autocatalysis, which takes aluminum isopropoxide as a catalyst to catalyze the reaction of metal aluminum and isopropanol to generate aluminum isopropoxide. Although the method can reduce the introduction amount of impurities, the catalytic reaction rate is low and the reaction time is long.

CN102050700A discloses a method for preparing alkoxy aluminum, which comprises the steps of putting aluminum wires and/or aluminum powder and aluminum ingots into a reactor, and adding fatty alcohol into the reactor in two parts under an inert environment, wherein the first part is less in addition amount and used for initiating a reaction, and the second part is more in addition amount and used for promoting the aluminum ingots and alcohol to react to generate alkoxy aluminum.

Disclosure of Invention

The invention aims to provide a preparation method of high-purity alkoxy aluminum, which can effectively shorten the reaction time of fatty alcohol and metallic aluminum and does not introduce other impurities except the impurities carried by the metallic aluminum.

The preparation method of the high-purity aluminum alkoxide comprises the steps of mixing high-purity aluminum with C in the presence of activated aluminum₃～C₆The fatty alcohol of (1): 3-5 mol ratio is reacted at the temperature not higher than the boiling point of alcohol to obtain high-purity alkoxy aluminum, the mass ratio of the activated aluminum to the high-purity aluminum is 1-10%, and the activated aluminum isThe aluminum is low-purity aluminum and C₃～C₆The fatty alcohol of (1): 1.5-2.9, wherein the purity of the low-purity aluminum is not more than 99.90 mass percent, and the purity of the high-purity aluminum is not less than 99.99 mass percent.

The method takes the activated aluminum with lower purity as the catalyst for initiating the reaction, so that the fatty alcohol and the high-purity aluminum react to prepare the high-purity alkoxy aluminum, the reaction can be carried out under a milder condition, the reaction initiation time is short, the reaction rate is high, and the reaction time can be effectively shortened. In addition, the activated metallic aluminum used in the reaction is little, and other impurities except the impurities carried by the metallic aluminum are not introduced.

Detailed Description

The method of the invention mixes low-purity aluminum with C₃～C₆The fatty alcohol reacts according to the proportion of the excessive aluminum, the oxide film on the surface of the aluminum is removed, the residual metal aluminum after the reaction is activated aluminum which is used as a catalyst, and the high-purity aluminum and C are mixed₃～C₆The fatty alcohol reaction can reduce the occurrence of side reactions, improve the initiation rate and the reaction rate, and further shorten the initiation time and the reaction time. The catalyst used in the invention is obtained by activating low-purity aluminum with alcohol, has low impurity content, does not introduce foreign impurities, has small dosage, basically has no influence on the purity of the product, and can obtain high-purity alkoxy aluminum.

According to the method, the activated aluminum is prepared by reacting low-purity aluminum with fatty alcohol, and the purity of the low-purity aluminum is preferably 99.00-99.90 mass%. The low purity aluminum and C₃～C₆The molar ratio of the fatty alcohols of (a) is preferably 1: 2.1 to 2.9. Preferably, the activated aluminum obtained after the reaction is stored sealed with an inert gas, preferably nitrogen, before use. If the activated aluminum obtained after the reaction is exposed to air before use, the activity thereof is reduced.

The method of the invention mixes high-purity aluminum and C₃～C₆In the presence of activated aluminum, preferably, the high purity aluminum and C₃～C₆The molar ratio of the fatty alcohol(s) of (a) is 1: 3.2 to 4.5. Said activationThe mass ratio of the aluminum to the high-purity aluminum is preferably 2-9%.

In the method of the present invention, activated aluminum is prepared and high purity aluminum and C are added by using the activated aluminum as a catalyst₃～C₆The reaction temperature of the fatty alcohol(s) should be no higher than the boiling point of the alcohol, and the reaction temperature is preferably from 20 ℃ below the boiling point of the alcohol to the boiling point of the alcohol. The reaction temperature is too low, the initiation of the reaction is slow, and the reaction rate is slow; too high a reaction temperature may result in too rapid a reaction rate, resulting in too much heat evolution in a short time, too much temperature exceeding the boiling point of the aliphatic alcohol and bumping.

The high-purity aluminum and the low-purity aluminum in the method are aluminum blocks, aluminum beans, aluminum sheets, aluminum wires or aluminum scraps. Said C₃～C₆The fatty alcohol of (a) may be n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, n-hexanol or isohexanol.

In the process of the present invention, when the alcohol is C₅～C₆In the case of the fatty alcohol, after the alcohol and the high-purity aluminum start to react, the reaction is relatively rapid, and in order to prevent bumping caused by excessive heat generation in the reaction, two-step feeding is preferably adopted for the reaction, namely, the high-purity aluminum and the fatty alcohol used in the reaction are firstly divided into two parts, the first part of the high-purity aluminum and the fatty alcohol are contacted with the activated aluminum for reaction, and the second part of the high-purity aluminum and the fatty alcohol are added after the reaction is stable, wherein preferably, the mole number of the high-purity aluminum used in the first part accounts for 0.1-0.5 of the total mole number of the high-purity aluminum used, and the mole number of the alcohol used in the first part accounts for 0.1-0.5 of the total mole number of the alcohol used.

The present invention is illustrated in detail below by way of examples, but the present invention is not limited thereto.

Example 1

(1) Preparation of activated aluminum

13.6g of low-purity aluminum flakes (0.504mol) having a purity of 99.85 mass% was charged into a three-necked flask equipped with a heating and condensing system, the impurity content of which is shown in Table 1, and 105ml of anhydrous isopropyl alcohol (1.365mol) having a purity of 99.5 mass% was charged into the three-necked flask, and the metal aluminum was immersed therein.

Gradually heating to 82 ℃ to react the isopropanol with the low-purity aluminum sheetAnd keeping condensation reflux until no obvious bubbles are generated in the solution, cooling to 60 ℃, taking out the low-purity aluminum sheet left in the reaction as an activated aluminum sheet, and placing the activated aluminum sheet in N₂Sealing and storing.

(2) Preparation of high purity aluminum alkoxides

Taking 1.1g of the product prepared in the step (1) in N₂Adding activated aluminum sheets (0.041mol) preserved in a medium-sealed way and 13.5g of high-purity aluminum wires (0.5mol) with the purity of 99.99 mass percent into a three-neck flask with a heating and condensing system, and adding 140ml of anhydrous isopropanol (1.819mol) with the purity of 99.5 mass percent into the three-neck flask to immerse metal aluminum; gradually heating to 82 ℃, keeping condensation and reflux, initiating the reaction to start when bubbles emerge from the isopropanol, maintaining the reaction at 82 ℃ for continuous reaction until no obvious bubbles are generated in the reaction system, and finishing the reaction. The temperature was reduced to 60 ℃ to obtain 120.88g of an isopropyl alcohol solution of aluminum isopropoxide, and the initiation reaction time (charge time to initiation reaction start time) and the reaction time (start reaction time to end time) are shown in Table 2.

Maintaining the isopropanol solution of the aluminium isopropoxide at 65 ℃, adding 160g of deionized water for hydrolysis to generate an aluminium hydroxide slurry phase and an isopropanol phase, separating the isopropanol phase, washing the obtained aluminium hydroxide slurry phase with water to remove the entrained alcohol, and drying at 120 ℃ for 12 hours to obtain the high-purity aluminium hydroxide, wherein the purity and the impurity content of the high-purity aluminium hydroxide are shown in table 3.

Example 2

A high-purity aluminum alkoxide was prepared as in example 1, except that 13.36g (0.495mol) of a high-purity aluminum wire having a purity of 99.99 mass% was added in the step (2), and 0.16g (0.006mol) of the aluminum alkoxide prepared in the step (1) was added in the amount of N₂Sealing the preserved activated aluminum sheet. 115.91g of isopropanol solution of aluminum isopropoxide is obtained after temperature reduction, the initiation reaction time and the reaction time are shown in table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the isopropanol solution of aluminum isopropoxide are shown in table 3.

Example 3

A high-purity aluminum alkoxide was prepared as in example 1, except that 13.1g (0.485mol) of a high-purity aluminum wire having a purity of 99.99% by mass was charged in the step (2), and 0.4g (0.015mol) of the aluminum wire prepared in the step (1) was charged in N₂Middle sealed preservationThe activated aluminum flake of (1). 115.89g of isopropanol solution of aluminum isopropoxide is obtained after temperature reduction, the initiation reaction time and the reaction time are shown in table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the isopropanol solution of aluminum isopropoxide are shown in table 3.

Example 4

A high-purity aluminum alkoxide was prepared as in example 1, except that 12.9g (0.478mol) of a high-purity aluminum wire having a purity of 99.99% by mass was added in the step (2), and 0.7g (0.026mol) of the aluminum alkoxide prepared in the step (1) was added in the amount of N₂Sealing the preserved activated aluminum sheet. 117.76g of isopropanol solution of aluminum isopropoxide is obtained after temperature reduction, the initiation reaction time and the reaction time are shown in table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the isopropanol solution of aluminum isopropoxide are shown in table 3.

Example 5

A high purity aluminum alkoxide was prepared as in example 1 except that (1) the amount of anhydrous isopropyl alcohol added was 70ml (0.910mol), (2) the temperature was decreased to 60 ℃ after the reaction to obtain 120.03g of an isopropyl alcohol solution of aluminum isopropoxide, the initiation reaction time and the reaction time are shown in Table 2, and the purity and the impurity content of the high purity aluminum hydroxide obtained by hydrolyzing the isopropyl alcohol solution of aluminum isopropoxide are shown in Table 3.

Example 6

1.0g of the compound prepared in example 1(1) under N₂Adding activated aluminum sheets (0.037mol) stored in a medium-sealed manner and 6.12g of high-purity aluminum wires (0.227mol) with the purity of 99.99 mass% into a three-neck flask with a heating and condensing system, and adding 100ml of anhydrous n-hexanol (0.793mol) with the purity of 99.5 mass% into the three-neck flask to immerse metal aluminum; gradually heating to 140 ℃, keeping condensation reflux, initiating a reaction when bubbles are blown out from n-hexanol, maintaining the temperature at 140 ℃, after the reaction is kept stable, adding 7.51g of high-purity aluminum wires (0.278mol) with the purity of 99.99 mass percent, continuously and slowly dropwise adding 126ml of anhydrous n-hexanol (0.999mol) with the purity of 99.5 mass percent, continuously reacting at the temperature until no obvious bubbles are generated in the reaction system, and finishing the reaction.

The temperature was reduced to 70 ℃ to obtain 189.90g of a n-hexyloxy aluminum solution in n-hexanol, and the initiation reaction time and the reaction time are shown in Table 2.

Adding 250g of deionized water into the n-hexanol solution of the n-hexyloxy aluminum, hydrolyzing at 90 ℃ to generate an aluminum hydroxide slurry phase and an n-hexanol phase, separating the n-hexanol phase, washing the obtained aluminum hydroxide slurry phase with water to remove entrained alcohol, and drying at 120 ℃ for 12 hours to obtain high-purity aluminum hydroxide, wherein the purity and the impurity content of the high-purity aluminum hydroxide are shown in table 3.

Example 7

Aluminum isopropoxide was prepared as in example 1, except that the catalyst added in step (2) was 1.1g of the aluminum metal sheet remaining after the reaction taken out in step (1) of example 1, which was not sealed with nitrogen but exposed to air before use. 120.11g of isopropanol solution of aluminum isopropoxide is obtained after temperature reduction, the initiation reaction time and the reaction time are shown in table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the isopropanol solution of aluminum isopropoxide are shown in table 3.

Comparative example 1

Aluminum isopropoxide was prepared by following the procedure of step (2) of example 1, except that 5.3g (0.026mol) of anhydrous aluminum isopropoxide was added to the reactants as a catalyst, 121.97g of an isopropyl alcohol solution of aluminum isopropoxide was obtained after cooling, the initiation reaction time and the reaction time are shown in Table 2, and the purity and the impurity content of high purity aluminum hydroxide obtained by hydrolyzing the isopropyl alcohol solution of aluminum isopropoxide were shown in Table 3.

Comparative example 2

Preparation of aluminum alkoxides according to the method of CN102050700A

Into a three-necked flask equipped with a heating and condensing system, 13.6g of a high purity aluminum wire (0.504mol) having a purity of 99.99 mass% was charged, and 70ml of anhydrous isopropyl alcohol (0.914mol) having a purity of 99.5 mass% was further charged to immerse the metallic aluminum.

Gradually heating to 82 ℃, keeping condensation reflux, initiating the reaction when bubbles emerge from the isopropanol, adding 70ml of anhydrous isopropanol (0.914mol) with the purity of 99.5 mass percent after the reaction is kept stable, keeping the temperature of the solution until no obvious bubbles are generated in the solution, and finishing the reaction. The temperature was reduced to 60 ℃ to give 120.13g of an isopropanol solution of aluminum isopropoxide, and the initiation and reaction times are shown in Table 2.

Maintaining the isopropanol solution of the aluminium isopropoxide at 65 ℃, adding 160g of normal temperature water for hydrolysis to generate an aluminium hydroxide slurry phase and an isopropanol phase, separating the isopropanol phase, washing the obtained aluminium hydroxide slurry phase with water to remove the entrained alcohol, and drying at 120 ℃ for 12 hours to obtain the high-purity aluminium hydroxide, wherein the purity and the impurity content of the high-purity aluminium hydroxide are shown in table 3.

Comparative example 3

Aluminum isopropoxide was prepared as in example 1, except that (1) the aluminum flake used in the preparation of activated aluminum was a high-purity aluminum flake having a purity of 99.99 mass%, and (2) the temperature was reduced to 60 ℃ after the reaction to obtain 120.07g of an isopropyl alcohol solution of aluminum isopropoxide. The reaction initiation time and the reaction completion time are shown in Table 1, the initiation reaction time and the reaction time are shown in Table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the isopropanol solution of the aluminum isopropoxide are shown in Table 3.

Comparative example 4

An aluminum hexoxide was prepared as in example 6, except that, without adding activated aluminum flake, the aluminum wire and the hexol were reacted by two additions and cooled to 70 ℃ to give 187.77g of a solution of aluminum hexoxide in n-hexanol. The initiation reaction time and the reaction time are shown in table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the n-hexyloxy aluminum in n-hexanol are shown in table 3.

Comparative example 5

Aluminum isopropoxide was prepared as in example 1, except that 35ml (0.456mol) of anhydrous isopropyl alcohol was added during the step (1) of preparing low-purity activated aluminum. (2) After the reaction, the temperature is reduced to 60 ℃ to obtain 120.01g of isopropanol solution of aluminum isopropoxide, the initiation reaction time and the reaction time are shown in table 2, and the purity and the impurity content of the high-purity aluminum hydroxide prepared by hydrolyzing the isopropanol solution of aluminum isopropoxide are shown in table 3.

TABLE 1

TABLE 2

Example number	Initiation of the reaction time min	Reaction time, h
			1	20	2
2	160	8
			3	120	3.5
4	30	2.5
			5	80	8
6	8	1.5
			7	50	3.5
Comparative example 1	70	15
			Comparative example 2	260	24
Comparative example 3	150	24
			Comparative example 4	15	2.0
Comparative example 5	100	14

TABLE 3