JPH0710781A - Production of branched olefin - Google Patents

Abstract

PURPOSE:To efficiently produce a branched olefin from a straight-chain olefin using a catalyst having high conversion of the straight-chain olefin and high selectivity of the branched olefin and free from problem of corrosion, etc., of apparatus because of absence of corrosive halogen. CONSTITUTION:The characteristic of this method for producing a branched olefin comprises isomerizing a skeleton of a straight-chain olefin in the presence of an alumina-zirconia-based catalyst prepared from an alumina-zirconia precursor sol and/or gel and having 0.2-40wt.% zirconia content to provide the objective branched olefin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a branched olefin by skeletal isomerization of a linear olefin. The branched olefin obtained by the present invention is a methyl tert-butyl ether (MTB) which is an octane number improver.
E), tertiary amyl methyl ether (TAME)
It is also useful as a raw material for the above and other petrochemical raw materials.

[0002]

_2. Description of the Related Art As a catalyst used in the production of branched olefins by skeletal isomerization of linear olefins, zirconium oxychloride (ZrOCl ₂ ) is supported on an alumina carrier (US Pat. No. 4,176,141). And U.S. Pat. No. 3,730,958), obtained by impregnating zirconia in an aqueous solution of a halogen acid and / or ammonium halide salt and then calcining (US Pat. No. 3,730,958). (See the specification), alumina activated with a chlorine compound such as hydrogen chloride or alkyl chloride (see JP-A-58-24529), and the like are known.

[0003]

The above-mentioned alumina-supported halogen-containing zirconia catalyst, halide-containing zirconia catalyst and chlorine-activated alumina catalyst of the above-mentioned alumina carrier have a predetermined linear olefin conversion and branching ratio when used for skeletal isomerization. Olefin selectivity can be obtained,
The catalysts of No. 1 and No. 2 contain halogens in the catalysts, and there are problems that the halogens in the catalysts are decomposed and scattered, the catalytic activity is lowered, and the apparatus is corroded.

Further, since the catalyst uses a corrosive and harmful compound such as hydrogen chloride when preparing the catalyst, there is a problem of equipment corrosion, and it is necessary to give sufficient consideration to safety when preparing the catalyst.

Therefore, the object of the present invention is to solve the above-mentioned drawbacks of the prior art, to have a high conversion of linear olefins and a high selectivity of branched olefins, and to contain no corrosive halogen, so that problems such as corrosion of the equipment can be solved. An object of the present invention is to provide a method for efficiently producing a branched olefin from a linear olefin using a non-catalyst.

[0006]

In the above-mentioned prior art US Pat. No. 3,730,958, zirconyl nitrate (ZrO (NO ₃ ) ₂ ) is added to alumina.
The skeletal isomerization rate when using a catalyst loaded with is much lower than that of an alumina single catalyst, whereas the skeletal isomerization rate of a catalyst where zirconium oxychloride (ZrOCl ₂ ) is loaded on alumina is It states that halogen-containing skeletal isomerization catalysts are preferred as linear olefin skeletal isomerization catalysts, with the data being much higher than that of alumina alone catalysts. However, halogen-containing catalysts have serious drawbacks such as equipment corrosion as described above.

[0007] Therefore, the present inventors have searched for a catalyst suitable for skeletal isomerization even if it does not contain halogen, in spite of the description in the above-mentioned US patent specification. As a result, the content of zirconia prepared from the alumina-zirconia precursor sol and / or gel was 0.2 to 40 wt.
% Halogen-free alumina-zirconia based catalyst,
It has been found to provide high linear olefin conversion and branched olefin selectivity and not cause equipment corrosion problems.

The present invention has been completed based on such findings, and has a zirconia content of 0.2 prepared from an alumina-zirconia precursor sol and / or gel.
A gist of a method for producing a branched olefin is characterized by skeleton isomerizing a linear olefin in the presence of an alumina-zirconia catalyst of 40 wt% to obtain a branched olefin.

The present invention will be described in detail below. The catalyst used in the method for producing a branched olefin of the present invention is (a) prepared from an alumina-zirconia precursor sol and / or gel (b) having a zirconia content of 0.2 to 40 wt%. As a requirement.

Explaining requirement (a) first, the alumina-zirconia precursor sol and / or gel can be obtained by a coprecipitation method or a cogel method using an aluminum compound and a zirconium compound.

The aluminum compound used is
Aluminum inorganic acid salts such as aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum bromide, aluminum fluoride and aluminum iodide; aluminates such as sodium aluminate and potassium aluminate;
Aluminum alkoxides such as aluminum i-propoxide, aluminum ethoxide, aluminum methoxide, aluminum n-propoxide, aluminum n-butoxide, aluminum i-butoxide, and aluminum sec-butoxide; and commercially available alumina sol.

Examples of the zirconium compound used include oxyzirconium salts such as zirconium oxynitrate and zirconium oxychloride; zirconium methoxide, zirconium ethoxide, zirconium n-propoxide, zirconium i-propoxide, zirconium n-butoxide, zirconium. Zirconium alkoxides such as tert-butoxide; zirconium salts such as zirconium acetate, zirconium chloride and zirconium fluoride; and commercially available zirconium sols.

The coprecipitation method is performed as follows, for example.
That is, a solution containing about 0.1 to 2.0 mol / l of an aluminum compound and about 0.1 to 2.0 mol / l of a zirconium compound is first prepared. Next, an aqueous ammonia solution, an organic amine, a base such as urea is added dropwise to the obtained solution at a temperature of room temperature to 60 ° C. to coprecipitate a mixture of an aluminum compound and a zirconium compound to obtain an alumina-zirconia precursor sol. Next, the obtained sol is aged at room temperature for, for example, 1 to 5 days to obtain an alumina-zirconia precursor gel composed of a mixture of aluminum hydroxide and zirconium hydroxide. This precursor gel is then filtered off, for example 100-14
After drying at 0 ° C for 5 to 24 hours, for example, 400 to 600 ° C
The desired alumina-zirconia-based catalyst can be obtained by performing a calcination treatment at (preferably 450 to 550 ° C.) for 1 to 5 hours.

On the other hand, the cogel method was obtained by separately preparing an alumina precursor sol and a zirconia precursor sol by adding a base to each solution without mixing the aluminum compound solution and the zirconium compound solution. Alumina precursor sol and zirconia precursor sol are aged to form an alumina precursor gel and a zirconia precursor gel,
Next, the obtained gels are filtered off, both gels are kneaded for 1 to 5 hours using a kneader, then dried and calcined to obtain the desired alumina-zirconia-based catalyst. Since the specific conditions in the co-gel method are almost the same as those in the co-precipitation method, the description thereof will be omitted.

In any of the coprecipitation method and the cogel method, even if a halogen compound is used as the aluminum compound and / or the zirconium compound, the halogen is removed by washing before filtration. The catalyst obtained does not contain halogen.

Next, the requirement (b) in the catalyst used in the present invention will be described. The requirement (b) limits the zirconia content in the catalyst to 0.2 to 40 wt%, and the reason for the limitation is as follows. When the zirconia content is less than 0.2 wt%, the linear olefin conversion is low, and when the zirconia content exceeds 40 wt%, the linear olefin conversion is low, and both of them have a high yield of branched olefin. Can't get On the other hand, when the zirconia content is 0.2 to 40 wt%, both the conversion of the linear olefin and the selectivity of the branched olefin are high, and the branched olefin can be obtained in a high yield. More preferable zirconia content is 0.3 to 30 wt%,
A particularly preferable zirconia content is 0.5 to 20 wt%.

The catalyst used in the present invention has been described above. In the method for producing a branched olefin of the present invention,
Conditions other than the catalyst are not particularly limited, and conventionally known conditions are adopted.

That is, as the linear olefin as a raw material, n-butene, n-pentene, n-hexene and the like n are used.
-Olefins are used. As the raw material, not only the linear olefins but also a mixture with other compounds such as paraffins may be used. The temperature condition for skeletal isomerization of the raw material olefin is usually 300 to 600 ° C.
Is used, and more preferably 400 to 500 ° C.

The reaction system is not particularly limited, either,
A fixed bed flow reaction system, a fluidized bed system, a moving bed system and the like are preferable. At that time, the space velocity (WHSV) of the raw material was 0.
1-15 are preferable and 0.3-5 are especially preferable. It is not essential to use a diluting gas in the reaction, but an inert gas such as nitrogen can also be used if necessary.

According to the method for producing a branched olefin of the present invention, since the catalyst used does not contain halogen,
There is no problem of corrosion of reactors. Moreover, since the catalyst used gives a high linear olefin conversion and a branched olefin selectivity, a branched olefin can be efficiently produced.

[0021]

The present invention will be further described with reference to the following examples. Example 1 (Preparation of catalyst) 72.78 g of aluminum nitrate and 1.54 g of zirconium oxynitrate were dissolved in 600 cc of distilled water to prepare an aqueous solution, and 91.0 g of 25% aqueous ammonia solution was added to the aqueous solution over about 1 hour. It was slowly dropped and coprecipitated to obtain an alumina-zirconia precursor sol.
The pH of the obtained sol was about 10. This sol was aged at room temperature for about 5 days to obtain an alumina-zirconia precursor gel composed of a mixture of aluminum hydroxide and zirconium hydroxide. The gel is then washed with water and filtered to obtain a white powder, which is dried at 120 ° C. overnight and dried at 550 ° C.
An alumina-zirconia-based catalyst was obtained by calcining in air for 3 hours.

The finally obtained alumina-zirconia catalyst had a zirconia content of 3 wt%.

(Production of Branched Olefin) In a fixed-bed flow reactor in which the alumina-zirconia-based catalyst obtained above was packed in a column, n-butene was used as a raw linear olefin at a flow rate of 20 cc / min (WHSV). = 0.9),
Nitrogen was supplied as a diluting gas at a flow rate of 100 cc / min, and a skeletal isomerization reaction of n-butene was performed at a reaction temperature of 450 ° C. to produce a branched olefin, isobutylene. The result after 1 hour was that the n-butene conversion was 23.
The isobutylene selectivity was 19.0 and the isobutylene selectivity was 89.0%. Therefore, the isobutylene yield was 20.6%.

Examples 2 to 6 The content of zirconia in the catalyst was 1 wt% (Example 2),
5 wt% (Example 3), 10 wt% (Example 4), 15
The same procedure as in Example 1 was carried out except that the amounts were changed to wt% (Example 5) and 30 wt% (Example 6). The results of skeletal isomerization of n-butene to isobutylene are shown in Table 1 together with the result of Example 1.

Comparative Examples 1-2 The zirconia content in the catalyst was set to 0.
Example 1 was performed in the same manner as in Example 1 except that 1 wt% (Comparative Example 1) and 50 wt% (Comparative Example 2) were used. The results are shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated except that commercially available alumina was used. The results are shown in Table 1.

Comparative Example 4 After immersing 18 g of alumina in an aqueous solution prepared by dissolving 4.16 g of zirconium oxynitrate in 100 cc of water and evaporating to dryness in a water bath, the obtained powder was dried at 120 ° C. for 16 hours, The catalyst was obtained by calcining at 550 ° C. for 3 hours. The zirconia content in the catalyst was 10 wt%. N was the same as in Example 1 except that the catalyst thus obtained was used.
-Skeletal isomerization of butene to isobutylene was carried out. The results are shown in Table 1.

[0028]

[Table 1] From Table 1, in Examples 1 to 6, the zirconia content was 1,3,5,10,15,30 wt% prepared via the alumina-zirconia precursor sol and / or gel.
When the alumina-zirconia-based catalyst of No. 1 was used, the conversion of n-butene and the selectivity of isobutylene were high, and isobutylene could be obtained in high yield. In particular, Example 1 using a catalyst having a zirconia content of 3, 5, 10, 15 wt%
Good results were obtained in 3 to 5.

On the other hand, even in the catalyst prepared via the alumina-zirconia precursor sol and / or gel, the zirconia content is 0.1 wt% (Comparative Example 1) and 50 wt% (Comparative Example 1), which are outside the limits of the present invention. In Comparative Example 2), n−
Butene conversion was low and isobutylene could not be obtained in high yield.

Comparative Example 3 using a commercially available alumina catalyst
Also, the n-butene conversion rate was low. Further, the conventional zirconium-based catalyst obtained by immersing the alumina in an aqueous zirconium oxynitrate solution and then evaporating it to dry solids had a lower n-butene conversion than that of the commercially available alumina catalyst of Comparative Example 3.

Example 7 The procedure of Example 1 was repeated except that WHSV was 0.45. As a result, the conversion of n-butene was 37.2% and the selectivity of isobutylene was 88.0%. A good result was obtained with a rate of 32.7%.

[0032]

EFFECTS OF THE INVENTION According to the present invention, there is provided a method capable of efficiently producing a branched olefin from a straight-chain olefin without causing a problem of corrosion of an apparatus or the like.

Claims (2)

[Claims] 1. An alumina-zirconia precursor sol and / or
Or prepared from gel, the zirconia content is 0.2 ~
A method for producing a branched olefin, which comprises skeletal isomerizing a linear olefin in the presence of 40 wt% of an alumina-zirconia catalyst to obtain a branched olefin. 2. An alumina-zirconia precursor sol and / or
Alternatively, the method according to claim 1, wherein the gel is obtained by a coprecipitation method or a cogel method using an aluminum compound and a zirconium compound.