Titanium-containing solid catalyst

Details Titanium-containing solid catalyst Titanium-containing solid catalyst

1998-03-23

2001-02-13

Trinh, Ba K. (Department: 1612)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

Reexamination Certificate

active

06187934

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Title of the Invention
The present invention relates a titanium-containing solid catalyst and a method for producing an oxirane compound. More particularly, the present invention relates to a titanium-containing solid catalyst used for producing an oxirane compound by reacting an olefin type compound with an organic hydroperoxide, the catalyst having high activity and enabling the intended conversion in a smaller reactor than that of a conventional method, and a method for producing an oxirane compound using said catalyst.
2. Description of the Related Art
A method for producing an oxirane compound by reacting anolefintypecompound withanorganic hydroperoxideusing a titanium-containing solid catalyst is well known (Japanese Patent Application Publication (JP-B) Nos. 56-35,941, 54-40,525, 54-40,526, 50-30,049, and Japanese Patent Application Laid-Open (JP-A) No. Hei 8-269,031).
A titanium-containing solid catalyst can be produced in various methods. For example, a production method in which a titanium compound is supported on silica and is calcined is one useful method. However, catalysts produced by the conventional methods have problems that activity is insufficient, an excessively large reaction vessel is required for industrial scale production, production cost is increased, and the like.
SUMMARY OF THE INVENTION
The present inventors have intensively studied a catalyst having no above-described problems, and found that a titanium-containing solid catalyst using specific silica or silica which has been specifically treated as a carrier, or a titanium-containing solid catalyst in which titanium content in a silica carrier is controlled in a specific range, is highly active when used in a method for producing an oxirane compound, and completed the present invention.
Namely, the present invention is a titanium-containing solid catalyst used for producing an oxirane compound by reacting an olefin type compound with an organic hydroperoxide, wherein the catalyst is obtainable by at least one method selected from the following (1) to (3):
(1) a titanium compound is supported on silica having an average pore diameter (D) measured by a mercury pressing method of 5 nm or more and having pore distribution in which at least 60% of pore volume is composed of pores having a pore diameter within the range of D±0.3 D (nm), and is calcined,
(2) silica is impregnated in water, then dried, and a titanium compound is supported on the silica, then calcined,
(3) silica is impregnated in a titanium-containing impregnation solution satisfying the following [formula-1], and is calcined
A/B≦
0.2 [formula-1]
A: mol number of metal titanium in the impregnation solution
B: mol number of a silanol group existing in silica.
As a titanium-containing solid catalyst of the present invention, there can be used a catalyst obtainable by a method in which (1) a titanium compound is supported on silica having an average pore diameter (D) measured by a mercury pressing method of 5 nm or more and having pore distribution in which at least 60% of pore volume is composed of pores having a pore diameter within the range of D±0.3 D (nm), and is calcined,
The silica used contains silicon in the form of a dioxide preferably in an amount of 50% or more, more preferably 75% or more, and further preferably 90% or more. It is preferable that the silica used has relatively large specific surface area, and the specific surface area is preferably 1 m
2
/g or more, and more preferably 25 to 800 m
2
/g.
The silica used is preferably porous synthetic silica of close packing type having relatively high density composed of an amorphous silica particle coagulated or bonding each other, and for example, silica gel and precipitated silica are listed. Production methods and properties thereof are described in R. G. Irer ed. “The ColloidChemistryof SilicaandSilicate” (Cornel University Publication Department, New York, USA, (1955 )) chapter VI and U.S. Pat. No. 2,657,149. Among commercially available silica gels, silica gel having a specific surface area of 25 to 700 m
2
/g, a pore volume of 0.3 to 2.0 ml/g, and a silica content of 99% by weight or more is preferable used.
Regarding the silica used, the average pore diameter (D) measured by a mercury pressing method is required to be 5 nm or more, preferably from 8 nm or more to 45 nm or less, and more preferably from 12 nm or more to 40 nm or less. When the average pore diameter (D) is less than 5 nm, activity remarkably decreases.
On the other hand, when the average pore diameter (D) is over 12 nm, selection ratio of an oxirane compound remarkably increases.
Further, the silica used is required to have pore distribution in which, based the average pore diameter (D) measured by a mercury pressing method, at least 60% of pore volume is composed of pores having a pore diameter within the range of D±0.3 D (nm), and it is preferable that the pore distribution of the silica is substantially uniform.
For supporting Ti, both a gas phase supporting method and a liquid phase supporting method can be applied. In the gas phase supporting, titanium salts and titanates of organic acids and inorganic acids, which are able to vaporize at supporting temperature, are applied. In the liquid phase supporting, titanium salts and titanates of organic acids and inorganic acids, which can be solved in a solvent, can be used.
Examples of the titanium compound include tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, tetraisobutyl titanate, tetra-2-ethylhexyl titanate, tetraoctadecyl titanate, titanium tetrachloride, titanium tetrabromide, titaniumtetraiodide, titanium (IV) oxyacetyl acetonate, titanium (IV) diisopropoxidebisacetyl acetonate and the like. A multi-stage supporting method which includes or does not include a drying and/or calcining step can be used.
As a suitable supporting, washing solvent in the liquid-phase supporting, oxa and/or oxo substituted hydrocarbons which are liquid at ordinary temperature having 1 to about 12 carbon atoms can generally be used. As a suitable solvent, alcohols, ketones, ethers (non-cyclic or cyclic type) and esters can be used. Examples thereof include hydroxy-substituted hydrocarbons such as methanol, ethanol, ethylene glycol, propylene glycol, isopropanol, n-butanol and octanol; oxo-substituted hydrocarbons such as acetone, diethyl ketone, methyl ethyl ketone and methyl isobutyl ketone; hydrocarbon ethers such as diisobutyl ether and tetrahydrofuran; and hydrocarbon esters such as methyl acetate, ethyl acetate, butyl acetate and butyl propionate, and the like.
Following the liquid-phase supporting, it is preferable to remove the absorbed solvent. This solvent removing operation may include decantation, filtration, centrifugal separation, vacuum gas discharge, drying and other operations. In this solvent removing operation, conditions are selected so that an excess solvent for supporting is removed from silica in an amount preferably at least 80% and more preferable at least 95%.
As described in Japanese Patent Application Laid-Open (JP-A) No. Hei 8-269,031, it is preferable to conduct washing after liquid-phase supporting treatment. A solvent for washing and a catalyst after Ti supporting are fully mixed, then a liquid-phase portion is separated by a method such as filtration, decantation or the like. This sequence is repeated for required times. Completion of the washing can be known by analysis of the liquid-phase portion. The washing temperature is from preferably 0 to 100° C., more preferably from 10to 60° C. Aftercompletionof thewashing, the remaining solvent for washing is removed by the same method as that in the impregnating solvent removing process. This solvent removal is useful for recovering a large amount of the solvent, simultaneously for decreasing ignition danger in calcining period, and for preventing decrease in physical strength of a catalyst derived from rapid evaporation of a large amount of a volatile solvent

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