JPH07256102A - Production of solid base catalyst - Google Patents

Abstract

PURPOSE:To produce a high activity solid base catalyst effective to a reaction such as aldol condensation or the isomerization, dehydrogenation or partial hydrogenation of olefin and not causing fine powdering at the time of the reaction. CONSTITUTION:Trialkoxy aluminum is hydrolyzed with an aq. soln. prepd. by dissolving one or more kinds of compds. of alkaline earth metals, preferably a barium compd. The resultant precipitate is dried and burnt at 300-900 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a solid base catalyst. More specifically, it relates to a method for producing a solid base catalyst useful for reactions such as aldol condensation, olefin isomerization, dehydrogenation and partial hydrogenation.

[0002]

2. Description of the Related Art Base catalysts are industrially very important catalysts used in reactions such as aldol condensation, olefin isomerization, dehydrogenation, and partial hydrogenation, but successful industrialization of heterogeneous base catalysts is Not many yet. Generally, a reaction using a heterogeneous solid catalyst has the following advantages as compared with a homogeneous catalyst reaction. (1) There is no or very little waste water, since operations such as catalyst neutralization and washing are unnecessary. (2) The catalyst can be reused. (3) In many cases, the selectivity is high. Therefore, it is expected that the use of the heterogeneous solid catalyst will simplify the process as compared with the case where the target product is obtained using the homogeneous catalyst, the cost of the plant will be low, and the target product can be obtained in a high yield. However, the basic catalysts that have been used industrially are mainly homogeneous catalysts represented by sodium hydroxide, and there are not many examples of heterogeneous catalysts. The cause of this is as follows.

[0003]

A typical solid base catalyst is an alkaline earth metal oxide, but such an alkaline earth metal oxide alone does not react sufficiently because the mechanical strength of the catalyst is insufficient. The powdering of the catalyst takes place therein. The pulverized catalyst may cause blindness from the filter cloth in a process such as the subsequent filtration, resulting in damage to the transport pump or decomposition of the product in the rectification step, which further hinders the subsequent process. In order to prevent this pulverization, there is a method to make a composite oxide of an alkaline earth metal and another metal using aluminum oxide, etc., but with a composite oxide prepared by the coprecipitation method of water-soluble compounds, the reaction activity Was small and was not satisfactory as a solid base catalyst.

The present inventor has diligently studied to solve these drawbacks of the solid base catalyst and to develop a highly active solid base catalyst without pulverization. As a result, alkoxyaluminum is used as one or more alkaline earth metals. By hydrolyzing with an aqueous solution in which the compound is dissolved and using the resulting precipitate,
It became possible to complete the present invention.

[0005]

The present invention provides the following (1) to
It is composed of item (3). That is, (1) A method for producing a solid base catalyst, characterized in that trialkoxyaluminum is hydrolyzed with an aqueous solution in which one or more alkaline earth metal compounds are dissolved. (2) The method according to (1) above, wherein the alkaline earth metal compound is a barium compound. (3) A solid obtained by hydrolyzing trialkoxyaluminum with an aqueous solution in which at least one alkaline earth metal compound is dissolved, drying the obtained precipitate, and then firing at a temperature in the range of 300 to 900 ° C. Method for producing base catalyst.

The raw materials for preparing the catalyst of the present invention are described in detail below. The trialkoxyaluminum used in the present invention can be represented by the general formula Al (OR) ₃ (R is independently a hydrocarbon group having 1 to 10 carbon atoms). Specific examples of these compounds include trimethoxy aluminum, triethoxy aluminum, tree n-propoxy aluminum, tree i-propoxy aluminum, di-n-propoxy mono-i-propoxy aluminum, tri-n-butoxy aluminum, tree i-butoxy. Aluminum, tree t-butoxy aluminum, tree n-pentyloxy aluminum, tree 2
-Ethylhexyloxyaluminum and the like can be mentioned, but trialkoxyaluminum in which R is an alkyl group having 2 to 5 carbon atoms is preferable, and tri i-propoxyaluminum is particularly preferable.

The alkaline earth metal compounds used in the present invention include hydroxides, nitrates, carbonates and organic acid salts of magnesium, calcium, barium and the like. Of these, salts of barium hydroxide, barium nitrate, barium carbonate or barium organic acid are preferable, and barium hydroxide is particularly preferable.

A precipitate containing alkaline earth metal and aluminum was obtained by mixing trialkoxyaluminum with one or more aqueous solutions of the above alkaline earth metal compounds and hydrolyzing the trialkoxyaluminum. Aluminum alkoxide can be dissolved in an organic solvent such as 2-propanol or the solid can be used as it is, but preferably it is dissolved in the solvent and used. The temperature at which the two are mixed is around room temperature and there is no particular problem. As a mixing method, both can be mixed at once with stirring, or the other solution may be dropped into one solution. The reaction is completed in a short time, but stirring may be continued for several minutes or several hours.

The precipitate obtained is evaporated to dryness and then in a vacuum,
At a temperature of 300 ° C. to 900 ° C., preferably 300 ° C. to 800 ° C., in an inert gas or atmosphere, 0.5
By baking for 5 to 5 hours, preferably 1 to 3 hours, the solid base catalyst of the present invention composed of an oxide of an alkaline earth metal and aluminum can be obtained. The trialkoxyaluminum and the alkaline earth metal compound used preferably have a ratio of the alkaline earth metal oxide in the metal oxide after firing in the range of 10 to 90% by weight.

The solid base catalyst of the present invention is an aldol condensation,
It is effective for olefin isomerization, dehydrogenation, partial hydrogenation and other reactions.

[0011]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (hereinafter abbreviated as CS-12) by an aldol condensation reaction from isobutyraldehyde (hereinafter abbreviated as IBA) in Examples and Comparative Examples. The reaction conditions of the synthetic reaction were as follows. Reaction conditions Reaction temperature: 110 ° C., reaction time: 1 to 3 hours, batch reaction Catalyst amount: 1 wt% of total charged amount

(Example 1) Triisopropoxyaluminum (manufactured by Tokyo Kasei Co., Ltd., hereinafter abbreviated as ATIP) 2
0.4 g of 2-propanol (hereinafter abbreviated as IPA) 30
It was dissolved in 0 ml to prepare an IPA solution of ATIP.
Separately, 31.5 g of barium hydroxide octahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 200 ml of pure water, and the obtained barium hydroxide aqueous solution was added to the IPA solution of ATIP for hydrolysis. After evaporating to dryness, the mixture was calcined at 700 ° C. in a vacuum for 1 hour and used for a synthesis reaction of CS-12 from IBA. 2.0 g of the catalyst prepared in (Example 1), IB
100.9 g of A and 103.4 g of CS-12 were taken and put in a four-necked flask and reacted for 2 hours under the above conditions. After the reaction, the suspension of the catalyst was filtered and the liquid was transparent, and no skipping of the catalyst was observed. The results of the reaction were as follows. IBA conversion rate 86.0% CS-12 yield 77.4%

(Embodiment 2) 40.8 g of ATIP is IPA
It was dissolved in 600 ml to prepare an IPA solution of ATIP.
Separately, 16.7 g of barium hydroxide octahydrate was dissolved in 200 ml of pure water, and the obtained barium hydroxide aqueous solution was added to the IPA solution of ATIP for hydrolysis and evaporation to dryness, and then 700 ° C. It was calcined in a vacuum for 1 hour and subjected to a synthesis reaction of CS-12 from IBA. 10.3 g of the catalyst prepared in (Example 2), 329.7 g of IBA, CS-12
Of 410.8 g was put into a four-necked flask and reacted for 2 hours under the above conditions. The liquid after filtration of the catalyst suspension after the reaction was transparent and no skipping of the catalyst was observed. The results of the reaction were as follows. IBA conversion rate 85.7% CS-12 yield 70.3%

Comparative Example 1 Barium oxide (Wako Pure Chemical Industries, Ltd., Pr.G) was used in the reaction, and CS-1 from IBA was used.
It was subjected to 2 synthetic reactions. The catalyst prepared in (Comparative Example 1) was 2.0 g, IBA was 103.6 g, and CS-12 was 101.
Take 4g, put these in a four-necked flask and
The reaction was carried out over time. After the reaction, the suspension of the catalyst was filtered, and the liquid was suspended, and the catalyst was clearly skipped. The results of the reaction were as follows. IBA conversion rate 96.5% CS-12 yield 15.3%

Comparative Example 2 37.5 g of aluminum nitrate (GR manufactured by Wako Pure Chemical Industries, Ltd.) and 26.1 g of barium nitrate (GR manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved in 400 ml of pure water.
Separately from these, sodium hydroxide (Wako Pure Chemical Industries, Ltd. G
R) 2.0 g dissolved in pure water 50 ml was added to the above aqueous solution of a mixture of aluminum nitrate and barium nitrate,
The resulting precipitate was washed with water, dried, and calcined in vacuum at 700 ° C. for 1 hour to be subjected to a synthesis reaction of CS-12 from IBA.
The catalyst prepared in (Comparative Example 2) was 2.0 g, and IBA was 10 g.
4.0 g and 100.3 g of CS-12 were taken, put in a four-necked flask and subjected to the reaction under the above conditions for 3 hours. The results of the reaction were as follows. IBA conversion rate 3.8% CS-12 yield 3.7%

[0016]

EFFECTS OF THE INVENTION The solid base catalyst prepared by the method of the present invention does not require neutralization and washing with water for removing the catalyst from the reaction product as compared with the conventional homogeneous catalyst, and does not generate waste water. . Further, compared with the case of using the conventional alkaline earth metal oxide alone, there is no catalyst pulverization, and therefore, there is no omission during filtration, so there is no risk of interfering with subsequent operations. . Further, when used in reactions such as aldol condensation, olefin isomerization, dehydrogenation, and partial hydrogenation, the catalytic activity is higher than that of the barium oxide-aluminum oxide composite oxide obtained by the coprecipitation method of a water-soluble compound. Is large. Thus, the solid base catalyst obtained by the production method of the present invention is of great significance industrially.

Claims (3)

[Claims] 1. A method for producing a solid base catalyst, which comprises hydrolyzing trialkoxyaluminum with an aqueous solution in which at least one alkaline earth metal compound is dissolved. 2. The method according to claim 1, wherein the alkaline earth metal compound is a barium compound. 3. An aluminum alkoxide is hydrolyzed with an aqueous solution in which one or more alkaline earth metal compounds are dissolved, and the obtained precipitate is dried, and then 300 to 900.
A method for producing a solid base catalyst obtained by firing at a temperature in the range of ° C.