Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1999-10-20
2001-09-04
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06284931
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for efficiently producing a 3,3,5-trimethylcyclohexylidenebisphenol which is useful as a starting material of various polymers such as aromatic polycarbonates, aromatic polyether sulfones, aromatic polyether ketones, aromatic ethers and aromatic ether imides. More particularly, the present invention relates to a process for producing a 3,3,5-trimethylcyclohexylidenebisphenol, which enables continuous reaction processing.
BACKGROUND OF THE INVENTION
Some processes which are commonly employed in the production of bisphenol and are based on the reaction of phenol with 3,3,5-trimethylcyclohexanone conducted in the presence of an acid and a thiol are known in the art as being available for the production of 3,3,5-trimethylcyclohexylidenebisphenols, especially 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane being a reaction product of phenol and 3,3,5-trimethylcyclohexanone.
For example, Japanese Patent Laid-open Publication No. 2(1990)-88634 discloses a process for producing 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, which comprises reacting phenol with 3,3,5-trimethylcyclohexanone at a molar ratio (phenol/3,3,5-trimethylcyclohexanone) of 6/1 in the presence of a catalyst consisting of hydrogen chloride gas and an alkylmercaptan and removing unreacted phenol from the resultant reaction mixture by steam distillation.
Further, Published Japanese Translation of PCT Patent Applications from Other States, No. 8(1996)-505644 discloses a process for producing 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, which comprises reacting phenol with 3,3,5-trimethylcyclohexanone in the presence of a reaction promoting catalyst consisting of a mixture of hydrochloric acid and an alkanethiol such as octanethiol to thereby obtain a reaction mixture containing 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane as an adduct of phenol and 3,3,5-trimethylcyclohexanone and separating 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane from the reaction mixture.
Still further, Published Japanese Translation of PCT Patent Applications from Other States, No. 9(1997)-507250 discloses a process for producing 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, which comprises reacting a ketal or thioketal with phenol, the ketal or thioketal being to be synthesized from 3,3,5-trimethylcyclohexanone and a diol or mercaptoalcohol.
Moreover, Japanese Patent Laid-open Publication Nos. 5(1993)-213803 and 4(1992)-282334 disclose processes applicable to continuous processing, which comprise reacting a cyclohexanone with a phenol in the presence of an anhydrous insoluble cation exchange resin containing sulfonic groups (acidic anhydrous condensation catalyst) and &bgr;-mercaptopropionic acid or the like as a co-catalyst to thereby obtain a substituted cyclohexylidenebisphenol.
However, when 3,3,5-trimethylcyclohexanone is used as a starting material, the reaction is extremely slow (conversion of ketone 24 hr after the initiation of the reaction: 55%, see Comparative Example c) of Japanese Patent Laid-open Publication No. 4(1992)-282334). Further, the selectivity of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane is low (selectivity: 72%, see Example 6 of Japanese Patent Laid-open Publication No. 5(1993)-213803).
A continuous reaction processing provides effective means for enhancing the efficiency in commercial production. Continuous feeding of a reaction mixture can be mentioned as one of the requirements for the continuous reaction processing.
However, 3,3,5-trimethylcyclohexylidenebisphenols, especially 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, have the property of causing the viscosity of the reaction mixture to be abnormally high when the reaction is proceeded. Therefore, when the conventional processes described in the above publications are employed, either it is difficult to continuously feed a reaction mixture under conditions enhancing a reaction yield or, although a reaction mixture can be continuously fed, not only is the reaction rate extremely low but also the selectivity is poor.
Therefore, there is a demand for the development of a process for producing a 3,3,5-trimethylcyclohexylidenebisphenol, which process enables not only suppressing a rise of the viscosity of the reaction mixture but also obtaining the desired 3,3,5-trimethylcyclohexylidenebisphenol at high yield, and which process is applicable to not only the productivity enhancement in batch operation but also a continuous reaction processing.
OBJECT OF THE INVENTION
The present invention has been made with a view toward solving the above problems of the prior art. It is an object of the present invention to provide a process for producing a 3,3,5-trimethylcyclohexylidenebisphenol, which process enables not only suppressing a rise of the viscosity of the reaction mixture but also obtaining the desired 3,3,5-trimethylcyclohexylidenebisphenol at high yield, and which process is applicable to not only the productivity enhancement in batch operation but also a continuous reaction processing.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a process for producing a 3,3,5-trimethylcyclohexylidenebisphenol, comprising reacting a phenol with 3,3,5-trimethylcyclohexanone in the presence of an acid catalyst,
wherein a phenol (A) represented by the general formula:
wherein each of R
1
and R
2
independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, provided that R
1
and R
2
are not simultaneously alkyl groups having 4 carbon atoms,
is pre-reacted with 3,3,5-trimethylcyclohexanone (B) at a molar ratio ((A)/(B)) of 3 to 7 in the presence of an acid catalyst until the 3,3,5-trimethylcyclohexanone (B) exhibits a degree of conversion of at least 90 mol %; and then
the phenol (A) and/or an aromatic hydrocarbon (C) is added to the thus obtained reaction mixture and post-reacted to thereby obtain a 3,3,5-trimethylcyclohexylidenebisphenol.
The 3,3,5-trimethylcyclohexylidenebisphenol desired in the present invention is represented by the general formula:
wherein each of R
1
and R
2
independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, provided that R
1
and R
2
are not simultaneously alkyl groups having 4 carbon atoms.
It is preferred that the pre-reaction be performed by dropping a liquid mixture of the phenol (A) and 3,3,5-trimethylcyclohexanone (B) or a liquid mixture of the phenol (A), the aromatic hydrocarbon (C) and 3,3,5-trimethylcyclohexanone (B) into a system containing the phenol (A) or a liquid mixture of the phenol (A) and the aromatic hydrocarbon (C), water and an acid catalyst at 15 to 40° C. Further, it is preferred that the post-reaction be performed by adding the phenol (A) and/or the aromatic hydrocarbon (C) at one time or in divisions to the reaction mixture obtained by the pre-reaction.
In performing the post-reaction, the phenol (A) is preferably added to the reaction mixture obtained by the pre-reaction in such an amount that the molar ratio of total of the phenol (A) added in the pre-reaction and the pre-reaction to added 3,3,5-trimethylcyclohexanone (B) ((A)/(B)) is in the range of 5 to 10. Further, in performing the post-reaction, the aromatic hydrocarbon (C) is preferably added to the reaction mixture obtained by the pre-reaction in an amount of 10 to 30% by weight based on the reaction mixture obtained by the pre-reaction.
It is also preferred that the acid catalyst be a catalyst mixture composed of a mineral acid (a1) and a thiol (a2), the mineral acid (a1) being a hydrogen chloride gas and the thiol (a2) being an alkylmercaptan having 1 to 12 carbon atoms.
The phenol (A) is preferably phenol.
DETAILED DESCRIPTION OF THE INVENTION
The process for producing a 3,3,5-trimethylcyclohexylidenebisphenol according to the present invention will be described in detail below.
In the process for producing a 3,3,5-trimethylcyclohexylidenebisphenol according to the present invention, a phenol (A) is pre-reacted with 3,3,5-trimethylcyclohexanone (B)
Isota Yoichiro
Nakaguchi Toru
Takenaka Hiroshi
Yao Kazuhiko
Birch & Stewart Kolasch & Birch, LLP
Honshu Chemical Industry Co. Ltd.
Shippen Michael L.
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