JP3734542B2 - Solid acid catalyst and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid acid catalyst and a method for producing the same, and more particularly to a solid acid catalyst having high activity in various acid catalyzed reactions such as an isomerization reaction and little deterioration, and a method for producing the same.
[0002]
[Prior art]
In the chemical industry, many reactions that require an acid catalyst such as alkylation reaction, acylation reaction, esterification reaction, and isomerization reaction are known. Conventionally, acid catalysts such as sulfuric acid, aluminum chloride, hydrogen fluoride, phosphoric acid, and p-toluenesulfonic acid are used for this type of reaction. However, these acid catalysts have the property of corroding metals, and it was necessary to use expensive corrosion resistant materials or to perform corrosion resistance treatment. In addition, it is usually difficult to separate the reactants after the reaction, and a waste acid treatment is required, which requires a complicated process such as alkali washing, and has a serious environmental problem. Furthermore, it was very difficult to reuse the catalyst.
[0003]
In view of such a situation, the present inventors made contact with a sulfuric acid-containing metal oxide calcined at 350 to 800 ° C. after contacting a Group IV metal hydroxide or hydrated oxide with a sulfuric acid-containing solution. It was found that the acid strength was higher than 100% by mass sulfuric acid (H ₀ (Hammett acidity function) was −11.93), and a method for producing a sulfuric acid-containing solid acid catalyst was proposed (Japanese Patent Publication No. 59-6181). . Because of their high acid strength, these solid acid catalysts have high catalytic performance for various acid catalytic reactions such as alkylation, acylation, esterification, and isomerization, and are low in corrosiveness and can be separated from reactants. It has the advantages that it is easy and does not require waste acid treatment, and that the catalyst can be reused, and is expected to replace conventional acid catalysts in various industrial reactions.
[0004]
Further, a catalyst having an excellent catalyst life in the isomerization reaction of a linear hydrocarbon has been proposed by further supporting a Group VIII metal on such a sulfuric acid-containing solid acid catalyst (Japanese Patent Laid-Open No. 61-263932). No., JP 61-153140, etc.). Furthermore, a catalyst having excellent catalytic activity in the isomerization reaction of linear hydrocarbons has been proposed by containing an oxide of iron and manganese in a sulfuric acid-containing zirconia catalyst (US Pat. No. 4,918,041).
[0005]
[Problems to be solved by the invention]
However, since the sulfuric acid-containing solid acid catalyst produced by the above-described production method has a large amount of sulfuric acid that can be easily removed, the catalyst activity greatly changes. Further, the activity as a catalyst is not always sufficient. Furthermore, when the amount of sulfuric acid released is large, there is a concern that problems such as corrosion of the apparatus may occur.
[0006]
The present inventors added or supported 1 to 40% by mass of one or more tungsten or molybdenum compounds as the metal amount on zirconium hydroxide or amorphous zirconium oxide as a catalyst containing no sulfuric acid, A solid acid catalyst having high acid strength was proposed by firing at a temperature of 1000 ° C. (Japanese Patent Laid-Open No. 1-288339). However, since these catalysts are composed of metal oxides, the stability of the catalyst during the reaction is high, but the activity as a catalyst is not necessarily sufficient as compared with the catalyst containing sulfuric acid.
[0007]
For these reasons, there has been a demand for a solid acid catalyst with a small amount of sulfuric acid to be eliminated and a high catalytic activity.
[0008]
[Means for Solving the Problems]
As a result of the diligent research in view of the above situation, the present inventors have found that a solid acid catalyst obtained by calcining iron on zirconium hydroxide and calcining it and carrying sulfuric acid thereon and calcining at 700 ° C. for 24 hours is removed. It has been found that not only is sulfuric acid released, but also shows high catalytic activity. As a result of further investigation, after supporting one or more metal salts selected from iron group elements in the periodic table on Group IV A metal hydroxides or hydrated oxides of the periodic table, 100 to 500 A solid acid catalyst calcined in a temperature range of ℃, further containing a sulfuric acid content and calcined in a temperature range of 650 to 800 ° C. until the sulfur content in the catalyst becomes 0.2 to 0.7 mass%, It has been found that it has high activity in various catalytic reactions and is excellent in the stability of the catalyst during the reaction.
[0009]
The present invention has been made based on these findings, and an object of the present invention is to provide a solid acid catalyst that exhibits high activity in acid-catalyzed reactions such as isomerization and is excellent in stability during the reaction. is there.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention may comprise one or more metal hydroxide or hydrated oxide, one or more metal salts selected from the periodic table iron group element selected from the IV A periodic table Is then calcined in a temperature range of 100 to 500 ° C., and further contains a sulfuric acid content, and then the sulfur content in the catalyst is 0.2 to 0.7 mass% in a temperature range of 650 to 800 ° C. A solid acid catalyst and a method for producing the solid acid catalyst that are calcined to the extent that they have high activity in various catalytic reactions and are excellent in the stability of the catalyst during the reaction.
[0011]
Examples of the first IV A metals, titanium, zirconium or hafnium. These metals may be used alone or in combination of two or more. In the present invention, titanium and zirconium are particularly preferably used, but zirconium is most preferable when only one kind is selected.
[0012]
Group IV A metal hydroxides or hydrated oxides generally include the above Group IV A metal salts and organometallic compounds, such as oxychlorides, sulfates, chlorides, oxysulfates of these metals, It can be obtained by neutralizing or hydrolyzing alcoholate or the like. When two or more of these metals are mixed, they may be mixed in the state of hydroxide, hydrated oxide, alcoholate or the like, or calcined to form an oxide having a low water content and then mixed. May be. When it is desired to use a composite oxide as a main component, the former method can be suitably used.
[0013]
Examples of the metal of the iron group metal salt supported on or mixed with the Group IV A metal hydroxide or hydrated oxide include iron, cobalt, and nickel. In the present invention, iron is most preferable from the viewpoint of cost and catalyst performance. These metals are preferably used in the form of a metal salt, and the type of salt is not particularly limited, and examples thereof include nitrates, sulfates, fluorides, chlorides, bromides, iodides, ammonium salts and the like. These metal salts may be used alone or in combination of two or more. There are no particular restrictions on the loading or mixing method, but a normal impregnation method, a solid phase mixing method, or the like is preferably used.
[0014]
To one or more of the hydroxide or hydrated oxide selected from the periodic table the IV A group, carries one or more metal salts selected Karakara periodic table iron group element Alternatively, the mixed compound needs to be converted into an oxide state by firing and used as a carrier. Firing is performed in a temperature range of 100 to 500 ° C, preferably 100 to 400 ° C, and more preferably 100 to 350 ° C in a gas atmosphere such as air or nitrogen. If it is less than 100 degreeC, drying may become inadequate and a metal salt may not disperse | distribute uniformly. Moreover, when it exceeds 500 degreeC, catalyst activity will fall.
[0015]
Examples of the method for allowing the carrier thus obtained to contain a sulfuric acid content include a method of impregnating a sulfuric acid aqueous solution or an ammonium sulfate aqueous solution, a method of mixing ammonium sulfate in a solid phase, and the like. Of these, the method of impregnating with an aqueous sulfuric acid solution is particularly preferred.
[0016]
Finally, the support containing the sulfuric acid content is dried as necessary, and then further activated. The activation treatment is performed in a gas atmosphere such as air or nitrogen at a temperature of 600 to 900 ° C, particularly preferably 650 to 800 ° C. At this time, the sulfur content in the catalyst must be 1.0% by mass or less. Otherwise, a highly active catalyst cannot be obtained. The sulfur content in the catalyst decreases as the calcination time is increased and the calcination temperature is increased. Therefore, it is necessary to determine the firing time and firing temperature in advance using a test sample.
[0017]
Sulfur content of the obtained solid acid catalyst is 0.2 to 0.7 mass%. If the amount of sulfur is 1.0% by mass or more, the stability of the catalyst during the reaction is not necessarily high, and there is a possibility that the sulfuric acid will be eliminated.
[0018]
Further, the obtained solid acid catalyst can be used by mixing with a porous material such as zeolite, clay compound, activated carbon and the like.
[0019]
【Example】
Catalyst preparation examples (catalysts 1 to 4)
100 g of commercially available zirconium oxychloride was dissolved in 2 liters of distilled water, and 28% aqueous ammonia was added until the pH finally reached 8 while stirring the solution at room temperature to cause precipitation. The produced hydrated zirconia was filtered, washed with distilled water, and dried at 100 ° C. for 24 hours. The dried hydrated zirconia was impregnated with an aqueous iron (III) nitrate solution so that the amount of iron was 2% by mass relative to the dried hydrated zirconia. This was dried at 100 ° C. and then calcined at 300 ° C. for 3 hours in an air stream to obtain an iron oxide-zirconia carrier. 2 g of this iron oxide-zirconia support was immersed in 30 ml of 0.5 M sulfuric acid, excess sulfuric acid was removed by filtration, and then dried at room temperature. The dried sulfuric acid-treated product was calcined at 700 ° C. for 24 hours in an air stream to obtain Catalyst 1. The amount of sulfur in the catalyst 1 was 0.52% by mass. In addition, by changing the calcination temperature and calcination time of the dried sulfuric acid treatment product obtained in the same manner, catalyst 2 (calcination temperature 700 ° C., calcination time 48 hours, sulfur amount 0.39 mass%), catalyst 3 (calcination temperature 700 ° C.) , Calcination time 72 hours, sulfur amount 0.31% by mass) and catalyst 4 (calcination temperature 725 ° C., calcination time 6 hours, sulfur amount 0.61% by mass) were obtained.
[0020]
(Catalyst 5, 6; Comparative catalyst)
An iron oxide-zirconia support was obtained in the same manner as in the preparation examples of catalysts 1 to 4. 2 g of this iron oxide-zirconia carrier was immersed in 30 ml of 0.5 M sulfuric acid, excess sulfuric acid was removed by filtration, and then dried at room temperature. The dried sulfuric acid-treated product was calcined at 650 ° C. for 24 hours in an air stream to obtain catalyst 5. The amount of sulfur in the catalyst 5 was 1.07% by mass. Moreover, the calcination temperature and calcination time of the dried sulfuric acid treatment product obtained similarly were changed, and the catalyst 6 (calcination temperature 700 degreeC, calcination time 1 hour, sulfur amount 1.82 mass%) was obtained.
[0021]
(Catalysts 7 and 8; comparative catalysts)
100 g of commercially available zirconium oxychloride was dissolved in 2 liters of distilled water, and 28% aqueous ammonia was added until the pH finally reached 8 while stirring the solution at room temperature to cause precipitation. The produced hydrated zirconia was filtered, washed with distilled water, and dried at 100 ° C. for 24 hours. 2 g of this dried hydrated zirconia was immersed in 30 ml of 0.5 M sulfuric acid, and excess sulfuric acid was removed by filtration, followed by drying at room temperature. The dried sulfuric acid-treated product was calcined at 650 ° C. for 24 hours in an air stream to obtain catalyst 7. The amount of sulfur in the catalyst 7 was 1.27% by mass. Similarly, the obtained dried sulfuric acid-treated product was calcined at 700 ° C. for 24 hours in the air to obtain catalyst 8. The amount of sulfur in the catalyst 8 was 0.44% by mass.
[0022]
(Catalyst 9; Comparative catalyst)
100 g of commercially available zirconium oxychloride was dissolved in 2 liters of distilled water, and 28% aqueous ammonia was added until the pH finally reached 8 while stirring the solution at room temperature to cause precipitation. The produced hydrated zirconia was filtered, washed with distilled water, and dried at 100 ° C. for 24 hours. The dried hydrated zirconia was impregnated with an aqueous iron (III) nitrate solution so that the amount of iron was 2% by mass relative to the dried hydrated zirconia. This was dried at 100 ° C. and then calcined in an air stream at 700 ° C. for 24 hours to obtain catalyst 9.
[0023]
(Catalyst 10; Comparative catalyst)
Commercially available zirconium oxychloride (100 g) was dissolved in 2 l of distilled water, and 28% aqueous ammonia was added until the pH finally reached 8 while stirring the solution at room temperature to cause precipitation. The produced hydrated zirconia was filtered, washed with distilled water, and dried at 100 ° C. for 24 hours. This dry hydrated zirconia was impregnated with an aqueous iron (III) nitrate solution and an aqueous manganese (II) nitrate solution so that the iron content was 1.5 mass% and the manganese content was 0.5 mass% with respect to the dry hydrated zirconia, Further, an aqueous ammonium sulfate solution was impregnated so that the amount of sulfur was 4% by mass with respect to dry hydrated zirconia. The product was calcined in an air stream at 725 ° C. for 1 hour to obtain catalyst 10. The amount of sulfur in the catalyst 10 was 1.80% by mass.
[0024]
Activity test The catalyst activity was compared by measuring the conversion and selectivity of butane skeletal isomerization of the catalysts prepared as described above.
[0025]
For the catalytic activity, a fixed bed pulse reactor (He carrier gas flow rate: 20 ml / min, catalyst amount: 0.2 g, pulse size 0.05 ml, reaction temperature 60 ° C.) was used, and the reaction gas was directly subjected to gas chromatography (column VZ-7, 6 m, 30 ° C.), and the generated gas at the 10th pulse was analyzed. The catalyst was used after heat treatment at 300 ° C. for 1 hour under He flow before the start of the reaction.
The conversion rate of the reaction when each catalyst is used is shown below.
Catalyst 1 11.8%
Catalyst 2 14.1%
Catalyst 3 13.9%
Catalyst 4 10.7%
Catalyst 5 (comparative example) 0.3%
Catalyst 6 (comparative example) 0.6%
Catalyst 7 (comparative example) 0.0%
Catalyst 8 (comparative example) 0.0%
Catalyst 9 (comparative example) 0.0%
Catalyst 10 (comparative example) 0.9%
Note that the selectivity of isobutane in the reaction product in the case of using the catalysts 1 to 6 and the catalyst 10 was 90% or more.
[0026]
【The invention's effect】
The present invention shows a high catalytic function especially for acid-catalyzed reactions such as isomerization, is excellent in the stability of the catalyst during the reaction, is less corrosive, is easily separated from the reactants, and does not require waste acid treatment In addition, there are many effects that the catalyst can be reused.

Claims (4)

After supporting one or more metal salts selected from iron group elements of the periodic table on one or more metal hydroxides or hydrated oxides selected from group A of the periodic table IV Firing in a temperature range of 100 to 500 ° C., and further containing a sulfuric acid content, followed by firing in a temperature range of 650 to 800 ° C. until the sulfur content in the catalyst becomes 0.2 to 0.7 mass%. A process for producing a solid acid catalyst, characterized in that   The solid acid catalyst obtained by the manufacturing method of Claim 1. 2. The process for producing a solid acid catalyst according to claim 1, wherein the Group IVA metal according to claim 1 is titanium and zirconium. The method for producing a solid acid catalyst according to claim 1, wherein the iron group metal according to claim 1 is iron.