Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Sulfur or compound containing same
Reexamination Certificate
2000-08-11
2002-07-16
Dang, Thuan D. (Department: 1764)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Sulfur or compound containing same
C502S349000, C502S351000, C502S355000, C585S375000, C585S422000, C585S446000, C585S458000, C585S442000, C585S444000, C585S468000, C585S470000, C585S480000, C585S482000, C585S515000, C585S526000, C585S661000, C585S668000, C585S730000, C585S750000, C585S751000
Reexamination Certificate
active
06420305
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a solid acid catalyst having a high activity in an acid-catalyzed reaction system and having easy handleability and a method for producing the same.
BACKGROUND ART
In the chemical industry, there have been known acid-catalyzed reactions such as alkylation reactions, esterification reactions, and isomerization reactions. Hitherto, in these reactions, there have been used acid catalysts such as sulfuric acid, aluminum chloride, hydrogen fluoride, phosphoric acid, and paratoluenesulfonic acid. However, these acid catalysts have metal corroding properties so that the use of costly anticorrosive materials for a production apparatus or anti-corrosive treatment of a production apparatus has been required. Usually, not only is it difficult to separate the catalysts from the reactants after the reaction but also it is necessary to conduct disposal of waste acid and it is also inevitable to undergo a complex process such as alkali washing. Also, there are many problems from the environment viewpoints. Further, it has been very difficult to reuse the catalysts.
In order to solve these problems, there has been proposed a solid acid catalyst containing a sulfate group which has been obtained by contacting a hydroxide or hydrated hydroxide of a metal belonging to group IV of the Periodic Table with a solution containing a sulfureous component and calcining the mixture at 350 to 800° C. (Japanese Patent Publication No. 59-6181). The solid acid catalyst has an acidity higher than that of 100% sulfuric acid (Hammett acidity function H
0
is −11.93). Because of their high acidity, the solid acid catalysts exhibit high catalyzing power in various acid-catalyzed reactions and have advantageous features that they show low corrosiveness, can be separated easily from the reactants, do not require disposal of waste acids, and can be reused, so they are expected to be substituted for conventional acid catalysts.
It has been also known that a catalyst obtained by impregnating platinum into a catalyst that has been obtained by the calcination of a sulfureous component-containing zirconia gel exhibits good activity for an isomerization reaction of hydrocarbons (U.S. Pat. No. 3,032,599).
As the methods for producing metal oxide catalysts that contain a platinum-family metal and a sulfureous component and are used mainly in the isomerization of hydrocarbons, there have been disclosed a method in which the step of calcination has been eliminated between the steps of treatment with a sulfureous compound and supporting of a platinum-family metal, a method in which the order of the steps of treatment with a sulfureous compound and supporting of a platinum-family metal are reversed, and a method in which the kind of sulfureous compound is changed in Japanese Patent Publication Nos. 5-29503, 5-29504, 5-29505, and 5-29506.
Also, it has been known that a solid acid catalyst obtained by adding a sulfureous compound to aluminum hydroxide or oxide followed by calcination exhibits an acidity higher than 100% sulfuric acid (Japanese Patent Application Laid-open No. 5-96171, Arata, Trends in Physical Chemistry, vol. 2, item 1 (1991)).
Japanese Patent Application Laid-open No. 9-38494 discloses a method for the production of a metal oxide shaped catalyst treated with a sulfate group. The method is characterized by preliminarily calcining a shaped material shaped from a metal hydroxide and boehmite at a temperature of 300° C. to 500° C. and then treating it with a sulfate group, which is a method for shaping a catalyst utilizing alumina as a binder. However, its catalytic activity is decreased as compared with a powder catalyst containing no boehmite due to the shaping with the addition of the boehmite. Also, it is disclosed that a shaped material obtained by using a metal hydroxide and boehmite powder, when dried at a temperature below 300° C., will be pulverized and destroyed by addition of water and that a catalyst obtained by kneading a mixture of platinum-containing sulfated zirconia catalyst powder (a powdery catalyst composed of zirconia supporting thereon platinum and a sulfate group) and boehmite powder with the addition of water, followed by shaping and calcination has a greatly decreased catalytic activity.
Solid catalysts, when utilized, must be shaped catalysts, which are easy to separate from the reactants and reuse as opposed to the powder form. However, even if catalysts have sufficient catalytic activity when they are in the form of a powder, shaping of them will make it impossible to obtain the mechanical strength that is required at the time of reaction/production or their catalytic activity will decrease accompanying their shaping. Thus, there has been made no report on a method for producing a solid acid shaped catalyst that satisfies the characteristics required as a catalyst and has a required mechanical strength.
DISCLOSURE OF THE INVENTION
The present invention solves these problems and provides a solid acid catalyst having a sufficiently high activity, an easy handleability sufficient for practical use and a sufficient mechanical strength, and which is a shaped product of the solid acid catalyst containing a sulfureous component, a method for producing the same, and a reaction method using such a catalyst.
As a result of extensive research on a method for producing the solid acid catalyst, the present inventors have now found that kneading zirconium hydroxide having specific physical properties, pseudoboehmite having specific physical properties, and ammonium sulfate, followed by shaping and calcination can give rise to a solid acid catalyst having an excellent catalytic activity and a sufficient mechanical strength, and further made research on the catalyst to complete the present invention.
According to a first aspect of the present invention, a method for producing a solid acid catalyst comprises the steps of: fabricating a support comprising a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina and having a peak diameter in the range of 0.05 to 1 &mgr;m in a pore diameter distribution of 0.05 to 10 &mgr;m; and having a sulfureous component supported on the support.
According to a second aspect of the present invention, a method for producing a solid acid catalyst comprises the steps of: fabricating a support comprising a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina in which pores having a pore diameter of not less than 0.05 &mgr;m and not more than 1 &mgr;m occupy a pore volume of 0.05 to 0.5 ml/g and pores having a pore diameter of above 1 &mgr;m and not more than 10 &mgr;m occupy a pore volume of below 0.05 ml/g; and having a sulfureous component supported on the support.
According to a third aspect of the present invention, a method for producing a solid acid catalyst comprises the steps of: kneading powder comprising zirconium hydroxide and/or hydrated oxide whose agglomerated particles have an average particle diameter of 0.2 to 10 &mgr;m with powder comprising aluminum hydroxide and/or hydrated oxide having a fibrous particle form, shaping the mixture to fabricate a support; and having a sulfureous component supported on the support. In this case, it is preferred that the above-mentioned support has a peak diameter in the range of 0.05 to 1 &mgr;m in a pore diameter distribution of 0.05 to 10 &mgr;m and in which pores having a pore diameter of not less than 0.05 &mgr;m and not more than 1 &mgr;m occupy a pore volume of 0.05 to 0.5 ml/g and pores having a pore diameter of above 1 &mgr;m and not more than 10 &mgr;m occupy a pore volume of below 0.05 ml/g. It should be noted that it is preferred to conduct the step of fabricating a support and the step of having a sulfureous component supported on the support in one step simultaneously.
The solid acid catalyst of the present invention is a catalyst which is constituted by a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina, contains a sulfureous compon
Aimoto Kohjiroh
Matsuzawa Kenji
Seki Kazuhiro
Dang Thuan D.
Flynn ,Thiel, Boutell & Tanis, P.C.
Japan Energy Corporation
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