JPS59227724A - Preparation of porous alumina-titania - Google Patents

Abstract

PURPOSE:To prepare porous alumina.titania having pore distribution of two mode type, by dividing a given amount of an aluminum salt and titanuium sulfate, blending them to give an aqueous solution, changing the pH of it from low to high, repeating these operations >= fixed times. CONSTITUTION:Part of a given amount of an aluminum salt such as aluminum sulfate, etc. and titanium sulfate is blended, and, if necessary, an acid is added to it, go give an aqueous solution at >= 4pH, an alkali such as an aqueous solution of NaOH, etc. is added to it, the solution is adjusted to >=6pH, stirred preferably at about 40-100 deg.C, to co-precipitate the aluminum salt and titanium sulfate. They are further blended with part of a given amount of the aluminum salt and titanium sulfate, and adjusted to a proper pH. These operations are repeated >=4 times, preferably about 6-12 times dividedly, the prepared gelatinous coprecipitate is washed with water, molded, dried, calcined at about 300- 1,000 deg.C, to give porous alumina.titania molded article having pore distribution with two peaks at a larger pore diameter side and a middle or small pore diameter side.

Description

[Detailed Description of the Invention] The present invention relates to a method for producing porous alumina and titania,
In detail, when producing porous alumina/titania from aluminum salts and titanium sulfate, the raw materials are divided into two parts using a coprecipitation method and a specific operation is repeated.
The present invention relates to a method for producing porous alumina-titania having a modal pore distribution.

Hitherto, porous molded bodies having a bimodal pore distribution have been widely used as catalysts or adsorbents for hydrotreating petroleum, etc., and various manufacturing methods have been proposed. For example, (1) a method in which activated alumina or alumina gel is mixed with carbon black, molded, and then fired (Japanese Patent Laid-Open No. 57
(2) A method in which alumina is mixed with a catalyst for fluid catalytic cracking and fired after molding (Japanese Patent Application Laid-open No. 123820).
12832), etc. In the bimodal supports obtained by these conventional methods, the peak of the pore distribution on the large pore diameter side is brought about by adding the second component, that is, the carbon black in the above method or the component in the catalytic cracking catalyst. It is something. Therefore, in conventional porous molded bodies having a bimodal pore distribution, each peak in the pore distribution is caused by a different component, and the same component cannot have two peaks. Therefore, the present inventors conducted intensive research in order to develop a porous molded body in which the two peaks of the pore distribution were not formed by different components, but were formed by the same component. Layered. As a result, it was found that the object could be achieved by repeatedly dividing and mixing the raw material compounds and adjusting the bale size within a certain range, thereby completing the present invention.

That is, in the present invention, when mixing aluminum salt and titanium sulfate to produce porous alumina/titania, (a) a part of the required amount of aluminum salt and titanium sulfate is mixed to form an aqueous solution of p(4 or less). A porous alumina characterized by carrying out an operation of preparing the porous alumina, and then (b) carrying out an operation of adding an alkali to the aqueous solution to adjust the pH to 6 or more, and repeating the operations of (a) and (b) four or more times.・Provides a method for producing titania.

The aluminum salt used in the present invention serves as a base for the resulting porous carrier, and various compounds can be used as long as they contain aluminum as a salt. In particular, aluminum salts of mineral acids such as aluminum sulfate and aluminum nitrate are suitable, and among them, aluminum sulfate, which becomes alumina without forming a medium 1fjT body upon heating, is most suitable. In the present invention, these aluminum salts are usually used in the form of an aqueous solution.

Next, titanium sulfate is used as the other raw material. Although titanium sulfate includes trivalent and tetravalent titanium compounds, since the operation of the present invention is carried out in an aqueous solution, a tetravalent titanium compound is preferably used. Titanium sulfate is also generally used as an aqueous solution.

In the method of the present invention, first, the necessary needles, that is, the required amounts of aluminum salt and titanium sulfate, are prepared for the desired amount of porous alumina-titania. The aluminum salt and titanium sulfate may each be used as they are, but in consideration of operational convenience, it is preferable to prepare them in the form of an aqueous solution or an aqueous mixture. The concentration of the aluminum salt and titanium sulfate in the aqueous solution (aqueous mixture) at this time is not particularly limited, but preferably 0.05 to 8 weight 11 titanium sulfate per 1 ooic of the aqueous solution (aqueous mixture). TiO□ conversion 10/
90 to 90/10 (weight ratio) is preferred.

In the method of the present invention, operation (a) is performed, which is an operation of mixing a portion of the aluminum salt and titanium sulfate thus prepared to prepare an aqueous solution of 4 or less. In preparing the aqueous solution at this time, powder or aqueous solution of aluminum salt and titanium sulfate may be added to previously prepared water, or the respective aqueous solutions may be simply mixed. In any case, since the method of the present invention involves repeating one operation, the entire required amount of aluminum salt and titanium sulfate should not be mixed at once, but should be divided into the number of repetitions and used each time. Must be.

Here, the amounts of aluminum salt and titanium sulfate used may be the same or different each time. In addition, the mixing ratio of aluminum salt and titanium sulfate is not particularly limited and may be determined as appropriate depending on the properties of the porous alumina/titania to be produced, but generally Al2O, /TiO
The mixing ratio of □ is preferably in the range of 10/90 to 90/10 (heavy/starvation ratio). Note that these mixing ratios may be set to be the same each time the repeated operation is performed, or may be appropriately changed and determined each time.

Further, in operation (a), it is necessary to maintain the value of the aqueous solution obtained by mixing the above-mentioned aluminum salt and titanium sulfate to 4 or less. Normally, by mixing an aqueous solution of aluminum salt and an aqueous solution of titanium sulfate in an appropriate ratio, it will be F444 or less without any special adjustment, but if necessary, it is also possible to adjust the field to the desired range by adding acid etc. be.

Furthermore, in this operation (a), there are no particular restrictions on the conditions and procedures for mixing the aluminum salt and titanium sulfate, as long as a uniform aqueous solution in which the aluminum salt and titanium sulfate are dissolved is obtained.

The method of the present invention involves performing the above operation (a) to obtain 14 (4
After preparing the following aqueous solution, perform operation (b) of adding an alkali to the aqueous solution to adjust the pH to 3 or more, preferably 6 to 10. The alkali used here generally includes various alkali aqueous solutions, Examples include sodium hydroxide aqueous solution and potassium hydroxide aqueous solution.

This step (b) involves moving the aqueous solution containing the aluminum salt and titanium sulfate prepared in step (a) from an acidic region of 4 or less to a neutral to alkaline region of 16 or more. aluminum salt and titanium sulfate are co-precipitated. Therefore, operation (b) can be carried out under conditions that cause coprecipitation, and usually after or while adjusting the liquid level by adding alkali to 6 or higher.
If a procedure such as stirring at a temperature of 40 to 100°C, preferably 60 to 100°C is followed, X.

In the method of the present invention, it is necessary to repeat the above-mentioned operations (a) and (bl) at least 4 times, preferably about 6 to 12 times. , a coprecipitate of aluminum salt and titanium sulfate is formed, which is filtered out, dried,
Alumina that has the desired pore distribution even after firing.
It won't be Titania.

Therefore, in the method of the present invention, after the first operation (b) is completed, a pre-measured amount of aluminum salt and titanium sulfate are newly added to the liquid containing the coprecipitate. Perform operation (a) of mixing and adjusting to 114 or less. In this second or subsequent operation (a), the conditions may be such that the coprecipitate generated in the previous operation (1)) is completely redissolved, or it may be only partially dissolved. . In addition, in the subsequent operation (b), if only a part of the coprecipitate was dissolved in operation (a), a new coprecipitate would be formed around the remaining coprecipitate, etc. A phenomenon different from the coprecipitation occurring in bl occurs, and as a result, the pore distribution of the resulting coprecipitate gradually approaches the desired two-mode type.

In the process of forming the above two-mode type, the operation (
In the step b) of adding an alkali to adjust the pH to 6 or above, the pH may be adjusted to a constant value at all times, or may be adjusted to a different value each time (however, the pH is 5 or higher). The final pore size (after repeating the operation four or more times) is important.The peak position of the peak of large pores in the pore distribution of porous alumina/titania created by changing this final pore size is important. can be changed within a certain range.

In the method of the present invention, after repeating the above operations (a) lb) four or more times, the resulting coprecipitate is filtered and thoroughly washed with water to remove sulfates, etc. from the gel-like coprecipitate. The components are eluted and removed to obtain a filter cake. Next, this cake is molded by extrusion molding etc., and after further drying,
The desired porous alumina/titania can be obtained by firing at a temperature of 400 to 700°C.

As described above, according to the method of the present invention, porous alumina chikunia having two peaks in pore distribution, one on the large pore diameter side and one on the medium and small pore diameter side, can be obtained. Moreover, in the method of the present invention, porous alumina/titania is produced by a coprecipitation method, so the two peaks in the pore distribution are formed almost simultaneously, which is different from the conventional bimodal porous carrier. A significantly different porous alumina-titania is obtained.

The porous alumina/titania thus obtained can be effectively used as a catalyst for hydrotreating heavy oil or its carrier, and various adsorbents.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Deionized water '1500# was placed in a 31 glass container with a lid, heated to 80°C while stirring, and then aluminum sulfate water M containing 8.0 wt% of alumina was added to this.
188.3g and 10. .

A homogeneous aluminum sulfate-titanium sulfate mixed solution obtained by mixing 7.85 g of a titanium sulfate aqueous solution containing 96.
159 was added. The field at this time was 2, and this state was maintained for 15 minutes. Next, 40 g of a 25-1 wt% aqueous sodium hydroxide solution was added to adjust the temperature to 8, and the mixture was heated at 180°C for 15 min.
Stirring was continued for a minute. After that, the operation of mixing the aluminum sulfate aqueous solution and the titanium sulfate aqueous solution mentioned above and the operation of adding a sodium hydroxide aqueous solution to adjust the FH were repeated five times, and then the final use was made with a 25.1 wt% sodium hydroxide aqueous solution. The temperature was adjusted to 80°C, and stirring was continued for 15 minutes at 80°C. Next, the alumina produced in the glass container
The titania gel was transferred to a suction filter to obtain a white filter cake. This filter cake was washed with 9 volumes of deionized water at 80° C. to elute the sulfuric acid rings present in the gel, and a white filter cake was obtained. With this cake extruder, 1111
! It was molded into a molded article of ψ.

The obtained molded product was dried in a hot air dryer at 120'C for 3 hours, and then fired in an electric furnace at 550'C for 3 hours to obtain porous alumina/titania.
．． / Tie2 = 90/10 (weight ratio) and ivy. The results are shown in Table 1 and Figure 1.

Example 2 ■ A porous alumina chip p=y was obtained by carrying out the same operation as in Example 1, except that in Example I, the temperature was adjusted to 7 using a 25-1 wt% sodium hydroxide aqueous solution. Ta. This one is Al2O, / Ti02 = 90/10
(weight ratio). The results are shown in Table 1 and Figure 2.

Example 3 In Example 1, %25. A porous alumina-titania was obtained by carrying out the same operation as in Example 1, except that Fall OK was adjusted using an Iwt% sodium hydroxide aqueous solution. This one is Al2O, /Tie2=90/10
(weight ratio). The results are shown in Table 1 and Figure 3.

Example 4 Except that in Example 1, the amount of aluminum sulfate aqueous solution containing 8.0 wt% as 1 alumina was 68.7 g, and the amount of titanium sulfate aqueous solution containing 1Qwt% as titania was 23.6 g. The same operation as in Example 1 was carried out to obtain porous alumina/titania.

This one is 1t20. /rio,, =70/3
0 (weight ratio). The results are shown in Table 1 and Figure 4.

Example 5 Porous alumina/titania was obtained by carrying out the same operation as in Example 1 except that the preparation temperature was 100°C. This one is Al 208/ Tie2=
The weight ratio was 90/10. The results are shown in Table 1 and Figure 5.

Example 6 Porous alumina/titania was obtained in the same manner as in Example 1 except that the repeated operation was repeated 12 times. This one is h71. o, /TiO□=9
The weight ratio was 0/10. The results are shown in Table 1 and Figure 6.

Example 7 In Example 1, 8.0 wt% of alumina was added instead of aluminum sulfate containing 8.0 wt% of alumina.
A porous alumina tetania was obtained in the same manner as in Example 1, except that aluminum nitrate containing 5% was used and the operation was repeated 9 times. This one is hz2o, / Tto2 = 90/10 (weight ratio)
Met. The results are shown in Table 1 and FIG.

Example 8 The same procedure as in Example 1 was carried out, except that the final concentration was adjusted to 7 using a 25-'Iwt% sodium hydroxide aqueous solution, and a porous aluminum was prepared.

Example 9 The same operation as in Example 1 was carried out, except that the final value of 25.1 wt% hydroxylated (25.1 wt%) +) was adjusted to 10 using an aqueous solution of Tsum, and porous alumina was prepared.・
Obtained Titania. This one is Al2Ome I゛10□29
The weight ratio was 0/10. The pore distribution is shown in FIG.

Comparative Example 1 Porous alumina/titania was obtained in the same manner as in Example 1 except that the repeated operation was repeated three times. This one is Al2O8/Tie2=90/
10 (weight ratio). The results are shown in Table 1 and Figure 8.

Comparative Example 2 Porous alumina/titania was obtained by carrying out the same operation as in Example 1 except that a 25-1 wt % aqueous sodium hydroxide solution was used and the temperature was adjusted to 5. This one is Al2O, / 'rio□=90/1
It was 0 (weight ratio). The results are shown in Table 1 and Figure 9.

Comparative Example 3 The same operation as in Example 1 was performed except that H#'7 was applied to field 3 using a 25.1 wt% IJ aqueous solution of hydroxide, and porous alumina/titania was prepared. Obtained. This one is AJ, O, /TiO, = 90/1
It was 0 (weight ratio). The results are shown in Table 1 and FIG.

[Brief explanation of the drawing]

Figure 1 shows the porous alumina titania obtained in Example 1, Figure 2 shows the porous alumina titania obtained in Example 2, and Figure 3 shows the porous alumina titania obtained in Example 3. , Figure 4 shows the porous alumina/titania obtained in Example 4, and Figure 5 shows the porous alumina/titania obtained in Example 5.
Titania, Figure 6 shows the porous alumina/titania obtained in Example 6, 7th FA shows the porous alumina/titania obtained in Example 7, and Figure 8 shows the porous alumina/titania obtained in Comparative Example 1. Titania, Figure 9 shows the porous alumina/titania obtained in Comparative Example 2, Figure 10 shows the porous alumina/titania obtained in Comparative Example 3, and Figure 11 shows the porous alumina obtained in Example 8.・Titania, and FIG. 12 shows 1iJ of each of the porous alumina/chichnia obtained in Example 9.
It is a graph showing the relationship between JI pore diameter and pore volume and between pore diameter and cumulative pore volume. In the figure, ΔV/ΔLOGD represents the rate of change between the pore volume (V) and the logarithm of the pore diameter (D).

Claims (1)

[Claims] (1) When mixing aluminum salt and titanium sulfate to produce porous alumina/titania, (a part of the required amount of aluminum salt and titanium sulfate is mixed and
The following steps are performed to prepare an aqueous solution, and then (b) an alkali is added to the aqueous solution to adjust the temperature to 6 or above, and the steps (a) and (b) are repeated four or more times. A method for producing porous alumina/titania.