JPH05168922A - Dehydration catalyst for aldol condensation, production of magnesium aluminum combinative compound and production of aldol condensation dehydration product using the catalyst - Google Patents

Abstract

PURPOSE:To obtain a magnesium aluminum combinative compound showing high activity by using only one kind of alkali by heating the precipitate formed by allowing ammonia to act on a solution of nitrates or org. acid salts of magnesium and aluminum to predetermined temp. CONSTITUTION:Ion exchange water, magnesium nitrate and aluminum nitrate are received in a container held under a nitrogen gas atmosphere in a predetermined ratio to form a solution and a solution consisting of 28% aqueous ammonia and ion exchange water is dripped to the formed solution under stirring to form a precipitate which is, in turn, filtered and washed to be dried under vacuum. After drying, the precipitate is heated and baked at 350-700 deg.C for 0.1-10hr. In this case, the use ratio of the magnesium salt and the aluminum salt is set to 10:1-1:5 and the use amount of ammonia is set to 0.5-2 times the theoretical equivalent of the magnesium salt and the alminum salt.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a magnesium / aluminum composite compound, a method for producing the same, and a method for producing an aldol condensation dehydration product using the same.

[0002]

2. Description of the Related Art A magnesium-aluminum composite compound is a well-known compound as a catalyst for producing an aldol condensation dehydration product by condensation dehydration of ketones and aldehydes, that is, an aldol condensation dehydration catalyst. As a method for producing the same, for example, a precipitate obtained by reacting sodium hydroxide with a solution of a magnesium salt and an aluminum salt is doped with a lithium or zinc salt, and then heated at a temperature of about 400 ° C. or lower. Method (JP
52-113390), a method of heating a precipitate obtained by adding a solution of a magnesium salt and a solution of an aluminum salt to a solution of sodium hydroxide and sodium carbonate at a temperature of 300 to 600 ° C. (JP-A-58-219139). Gazette) etc. are known.

[0003]

However, the magnesium-aluminum composite compound obtained by the known method is not sufficiently satisfactory in terms of catalytic activity, selectivity and the like. Moreover, in the above method, as raw materials,
There is a problem that not only a lithium or zinc salt is required but also a complicated operation of doping is required.
In another method, in the step of forming a precipitate,
There is a problem that two kinds of alkalis, sodium hydroxide and sodium carbonate, are required.

[0004]

The inventors of the present invention have conducted extensive studies to solve such drawbacks, and as a result, in the step of forming a precipitate, if a specific alkali of ammonia is used, high catalytic performance is exhibited. It was found that a magnesium-aluminum composite compound can be easily obtained, and further various studies were conducted to complete the present invention.

That is, in the present invention, ammonia is applied to a solution of at least one magnesium salt selected from magnesium nitrate and organic acid salts and at least one aluminum salt selected from aluminum nitrate and organic acid salts. To form a precipitate, and the precipitate was heated to 350-700
A high-performance aldol condensation dehydration catalyst characterized by being heated at a temperature of ℃

Ammonia is allowed to act on a solution of at least one magnesium salt selected from magnesium nitrate and organic acid salts and at least one aluminum salt selected from aluminum nitrate and organic acid salts to form a precipitate. An industrially excellent method for producing a magnesium-aluminum composite compound, characterized in that the precipitate is heated at a temperature of 350 to 700 ° C.

In producing an aldol condensate by condensing ketones, magnesium nitrate as a catalyst,
Ammonia is allowed to act on a solution of at least one magnesium salt selected from organic acid salts, a nitrate of aluminum, and at least one aluminum salt selected from organic acid salts to form a precipitate. The present invention provides an industrially excellent method for producing an aldol condensation dehydration product, which comprises using a magnesium-aluminum composite compound obtained by heating at a temperature of 700 ° C.

Next, the present invention will be described in more detail. As the magnesium salt used in the present invention, a water-soluble salt,
Examples thereof include organic acid salts such as magnesium nitrate and acetate. Examples of the aluminum salt include water-soluble salts such as aluminum nitrate and lactate. The use ratio of magnesium salt to aluminum salt is usually 10: 1 to 1: 5, preferably 3: 1 to 1: 1 in terms of atomic ratio.

According to the present invention, ammonia is allowed to act on a solution of a magnesium salt and an aluminum salt to form a precipitate. Ammonia is usually used as an aqueous solution. The amount of ammonia used is usually 0.5 to the theoretical equivalent of magnesium salt and aluminum salt.
It is 2 times, preferably 1 time or less.

When acting with ammonia, the ammonia solution is usually added to the above salt solution, but the salt solution may be added to the ammonia solution, or these three solutions may be poured together. It is also possible to introduce ammonia gas into the salt solution.

The formed precipitate is separated by means such as filtration. The separated precipitate is usually washed and dried,
It is fired at a temperature of about 350 to 700 ° C. Where about 35
Heating at a temperature up to 0 ° C. or at a temperature higher than about 700 ° C. is not preferable because the catalyst performance is deteriorated.
The heating and firing time is usually about 0.1 to 10 hours, though it depends on the heating temperature.

Thus, a magnesium-aluminum composite compound can be obtained, which compound is excellent as an aldol condensation dehydration catalyst. When used as a catalyst, it may be supported on a carrier or diluted with a diluent. Moreover, mechanical strength and the like can be improved by adding a binder and the like. Further, the reaction may be either a batch system or a continuous system. In the case of a continuous system, the catalyst bed may employ either a fixed system or a fluid system.

The raw materials for the aldol condensation dehydration reaction are:
Examples thereof include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, cyclopentanone, and cyclohexanone, and aldehydes such as acetaldehyde and butyraldehyde.

The condensation dehydration reaction can be carried out according to a known method. For example, when acetone is used to produce mesityl oxide, isophorone, etc., the reaction temperature is usually about 250 to 400 ° C, preferably 270 to 330 ° C. The pressure is usually from normal pressure to about 5 kg / cm ² . The feed rate of the raw material is usually about 0.1 to 10 h ^{-1 in} LHSV, preferably 1
~ 5h ^-1 .

[0015]

INDUSTRIAL APPLICABILITY The magnesium-aluminum composite compound of the present invention exhibits extremely high performance as an aldol condensation dehydration catalyst and efficiently gives a condensation dehydration product. Further, according to the present invention, a magnesium-aluminum composite compound exhibiting high performance can be obtained by using only one kind of alkali, ammonia, in the step of forming a precipitate.

[0016]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto.

Example 1-1 Under a nitrogen gas atmosphere at 15 to 20 ° C., 640 g of ion-exchanged water was put into a 3 l flask, and magnesium nitrate (Mg
_{(NO 3) 2 · 6H 2} O) 153.6g, aluminum nitrate (Al (NO _{3) 3} ·
9H ₂ O) (150 g) was added and dissolved, and this was added dropwise to a solution of 28% ammonia water (300.4 g) and ion-exchanged water (800 g).

After the dropping, the mixture was stirred for 3 hours, filtered, and filtered.
Washing with 00 g of ion-exchanged water was repeated 3 times. Then, after drying under reduced pressure at 100 ° C., baking was performed at 550 ° C. for 2 hours to obtain 43.4 g of a white solid.

Example 1-2 A stainless steel reaction tube (inner diameter 16 mmφ × 250 mm) was filled with 10 ml (6.53 g) of the catalyst (molded to 24-48 mesh) obtained in Example 1, and nitrogen gas was 20 ml / min. The internal pressure is 2.
It was kept at 8 Kg / cm ² G. Then, the temperature of the reaction tube was raised to 300 ° C., and then acetone was supplied at 10 ml / H. After about 18 hours,
The reaction liquid that flowed out was collected and the content of the product was measured by gas chromatography. Then, set the acetone flow rate to 10
The content of the product was measured in the range of -40 ml / H. The results are shown in Table 1. The recovery rate of the reaction solution with respect to the used acetone was 98 to 99%.

Table 1 Composition of reaction solution Acetone flow rate (ml / H) Acetone (wt%) Mesityl oxydide (wt%) Isophorone (wt%) 10 46.8 1.5 22.5 30 61.0 2.5 20.0 40 69.0 2.9 17.3 Mesityl oxidate; 4- Methyl-3-pentenone + 4-methyl-4-pentenone isophorone; 3,5,5-Trimethyl-2-cyclohexen-1-one + 3,5,5-Trimethyl-3-cyclohexen-1-one

Comparative Example 1-1 Under a nitrogen gas atmosphere at 15 to 20 ° C., 800 g of ion-exchanged water was placed in a 3 l flask, and 50% sodium hydroxide was added thereto.
192 g and 40 g of sodium carbonate were added and dissolved. Then, a solution containing 153.6 g of magnesium nitrate hexahydrate, 150 g of aluminum nitrate nonahydrate and 640 g of ion-exchanged water was added dropwise to this over 30 minutes. After stirring at 15 to 20 ° C for 3 hours, the temperature was raised to 65 ° C and the stirring was continued at the same temperature for 18 hours. After cooling to room temperature, filtration, washing and drying under reduced pressure were carried out in the same manner as in Example 1-1, followed by baking at 450 ° C. for 18 hours to give 35.2 g of a white solid.
Got

Comparative Example 1-2 Next, 10 ml of the above catalyst (molded to 24-48 mesh) (4.12
Using g), a reaction was carried out in the same manner as in Example 1-2, and the results are shown in Table 2. The reaction liquid recovery rate was 98 to 99%.

Table 2 Composition of Reaction Solution Acetone Flow Rate (ml / H) Acetone (wt%) Mesityl Oxide (wt%) Isophorone (wt%) 13.6 74.4 3.9 11.6 19.9 76.5 4.1 10.5 25.0 79.7 4.4 8.9

Examples 2-1 and 3-1, Comparative Example 2-1 White color was obtained according to Example 1-1, except that the magnesium salt and aluminum salt were changed as follows. A solid was obtained.

Table 3 Examples Magnesium salt (g) Aluminum salt (g) Example 2-1 Magnesium nitrate 6-hydrate 123.2 Aluminum nitrate 9-hydrate 180.1 Example 3-1 McNium nitrate 6-hydrate 263.3 Aluminum nitrate 9-hydrate 42.8 Comparative Example 2-1 Magnesium sulfate 7-hydrate 147.9 Aluminum sulfate 18-hydrate 133.3

Examples 2-2, 3-2, Comparative Example 2-2, except that the catalyst obtained as described above was used
The reaction was performed according to 1-2 and the results are shown in Table 4.
The recovery rates of the reaction solutions were all 98 to 99%.

Example 4 The reaction was carried out in the same manner as in Example 1-2 except that cyclohexanone was used instead of acetone in Example 1-2. After 2 hours, the reaction solution was sampled and analyzed by gas chromatography. The results were 3.7% for 2-cyclohexylidene cyclohexanone, 0.7% for 2- (1-cyclohexenyl) cyclohexanone, and 94.8% for cyclohexanone.

Table 4 Composition of reaction solution (wt%) Example Catalyst Acetone flow rate Acetone mesityl oxydiisophorone 4.7 ml / H 62.2 2.7 17.8 Example 2-2 Example 2-1 10 64.9 2.9 17.0 41.7 82.0 3.3 8.9 Example 3- 2 Example 3-1 5 66.3 3.1 14.2 43 86.1 3.2 5.5 Comparative example 2-2 Comparative example 2-1 10 87.2 3.8 4.2 40 96.7 1.4 1.0

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takeo Suzuka 2-10-1, Tsukahara, Takatsuki City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Masao Sasaki 2-10-1, Tsukahara, Takatsuki City, Osaka Prefecture No. Sumitomo Chemical Industry Co., Ltd.

Claims (3)

[Claims] 1. A solution of at least one magnesium salt selected from a magnesium nitrate and an organic acid salt and at least one aluminum salt selected from an aluminum nitrate and an organic acid salt is reacted with ammonia to cause precipitation. A catalyst for dehydration of aldol condensation, which is produced by heating the precipitate at a temperature of 350 to 700 ° C. 2. A solution of at least one magnesium salt selected from magnesium nitrate and organic acid salts and at least one aluminum salt selected from aluminum nitrate and organic acid salts is caused to act on ammonia to cause precipitation. A method for producing a magnesium-aluminum composite compound, wherein the precipitate is formed and the precipitate is heated at a temperature of 350 to 700 ° C. 3. A magnesium nitrate as a catalyst for producing an aldol condensate by condensing a ketone.
Ammonia is allowed to act on a solution of at least one magnesium salt selected from organic acid salts, a nitrate of aluminum, and at least one aluminum salt selected from organic acid salts to form a precipitate. A method for producing an aldol condensation dehydration product, which comprises using a magnesium-aluminum composite compound obtained by heating at a temperature of 700 ° C.