Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2003-03-07
2004-01-06
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06673975
ABSTRACT:
TECHNICAL FIELD
The invention relates to a process for production of high purity 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (referred to as “BPTMC” hereinafter) having stable quality in high yield and in high selectivity by an acid condensation reaction of phenol with 3,3,5-trimethylcyclohexanone (referred to as “TMC” hereinafter).
BACKGROUND ART
In recent years, BPTMC is used as raw materials for the production of optical products such as optical disks, as well as synthetic resins for optical use such as polycarbonate resins for optical use. A variety of processes for the production of BPTMC are already known. According to one of such processes, phenol is reacted with TMC using hydrogen chloride gas as a catalyst and an alkyl mercaptan as a promoter in the presence of an inactive organic solvent or in the absence of a solvent, and then phenol remained unreacted is removed from the reaction mixture by steam distillation, as described in Japanese Patent Application Laid-open No. 2-88634. It is also described therein that, after the reaction, water is added to the reaction mixture, and then an alkali to neutralize the reaction mixture, followed by heating, cooling and removing an aqueous phase, thereby obtaining the desired BPTMC as residue.
A further process is known, as is described in Japanese Patent Application Laid-open No. 8-505644. According to the process, phenol is reacted with TMC using hydrogen chloride gas as a catalyst and an alkyl mercaptan such as octanethiol as a promoter. After the reaction, water is added to the reaction mixture to form a slurry, and the slurry is filtered to provide 1:1 adduct crystals of BPTMC and phenol, and then the phenol is removed from the adduct crystals, thereby providing the desired BPTMC.
There is also known a process, as described in Japanese Patent Application Laid-open No. 4-282334, which provides the desired BPTMC by the reaction of phenol with TMC using water-insoluble cation exchange resins having sulfonic acid groups therein as a catalyst and a mercaptan compound as a promoter. In Japanese Patent Application Laid-open No. 5-213803, there is described a process in which an acid catalyst such as benzenesulfonic acid is added to a mixture of phenol, TMC, a mercaptan compound as a promoter and water, whereupon the reaction is started with stirring, and the desired BPTMC is obtained in high selectivity.
As mentioned hereinbefore, BPTMC is used as raw materials for polycarbonate resins for optical use. In order to supply BPTMC to this use, it is more and more strongly demanded to produce high purity BPTMC stably which is free of by-products derived from the reaction, and besides free of high boiling point by-products or colored by-products derived from purification processes for the obtained reaction product and residual phenol or trace impurities such as sodium.
In particular, it is most strongly demanded not only to suppress the generation of by-products such as isomers to improve the purity of the resultant BPTMC but also to reduce the amount of the residual phenol and trace impurities such as sodium, chlorine and sulfur derived from a catalyst or a promoter used in the reaction or an alkali used to neutralize the resultant reaction mixture as much as possible since such impurities give harmful influences on the resultant BPTMC when it is used as raw materials for polymers or when it is used for the production of electronic elements.
In general, in the production of BPTMC by an acid condensation reaction of phenol with TMC, the reduction of by-produced impurities such as isomers should be primarily achieved by improving the selectivity of the production of the desired product in the reaction. However, the impurities can be also reduced to a certain extent in a stage wherein the resultant reaction mixture is neutralized or in a stage wherein the resultant reaction product is purified. In fact, a variety of conditions under which the reaction mixture is neutralized or the reaction product is purified after the completion of the reaction have important significance in order to reduce the amount of trace impurities included in the resultant BPTMC.
Usually, in the reaction of phenol and TMC, the less the reaction temperature and the less the amount of reaction solvent used, the higher the selectivity of the reaction. But on the other hand, when the reaction temperature is low or the reaction solvent is used in a large amount, the reaction velocity is reduced inevitably, and besides, the reaction mixture increases in the viscosity as the reaction proceeds, resulting in difficult stirring. In addition, in the stage of neutralizing the resultant reaction mixture and of purifying the resultant reaction product, the improvement of purity of the reaction product and the reduction of impurities of the reaction product are contrary to each other in nature. Accordingly, it is very important to establish optimum combination of all the stages involved each having optimum operation conditions throughout the production stages in order to produce uncolored high purity BPTMC that is accompanied by impurities in a reduced amount as much as possible in a stable manner in high yields.
However, according to the known processes for production of BPTMC by the reaction of phenol with TMC, the selectivity of reaction is so small as about 70%, and besides no consideration has been heretofore paid to reduce the amount of trace impurities such as sodium included in the obtained product so long as the present inventors know.
Furthermore, according to the known processes, phenol is used usually in a large excess relative to TMC so that the filtrate obtained by filtering the reaction mixture after the reaction contains a large amount of phenol as well as BPTMC dissolved in the phenol and impurities such as isomers. Accordingly, it is also important to recover and reuse phenol or recover BPTMC from the resulting filtrate in order to produce advantageously BPTMC in an industrial scale.
On the other hand, a process for production of high purity 2,2-bis(4-hydroxyphenyl)propane (referred to as “bisphenol A” hereunder) is already described in, for example, Japanese Patent Application Laid-open No.5-392388, No.6-25048 or No. 6-25043.
In addition, with regard to bisphenol A, a process for production thereof including reuse of filtrate from a crystallization stage after the reaction is also proposed, for example, in Japanese Patent Application Laid-open No. 5-345737. According to the process, crystals of phenol adduct of bisphenol A are crystallized out of a phenol solution containing bisphenol A after the completion of the reaction, the crystals are collected by filtration, the resulting mother liquor is subjected to distillation to recover the phenol and the thus recovered phenol is recycled to the reaction stage. The bottom liquid in the distilling tower is heated and decomposed in the presence of an alkali catalyst. The resulting substance is recovered under a reduced pressure and purified by using an ion exchange resin, followed by recycle to the reaction stage.
In Japanese Patent Application Laid-open No. 6-321834, it is described that after phenol adduct crystals of bisphenol are crystallized and separated out of the reaction mixture, the resulting mother liquor is made contact with an acid catalyst to isomerize o- and p-isomers to p- and p′-isomers, and then the resulting isomers are returned to the crystallization stage for reuse.
Further in Japanese Patent Application Laid-open No. 10-59888, the following is described. Phenol is reacted with acetone in the presence of an ion exchange resin catalyst to produce bisphenol A, and the bisphenol A produced is led to a phenol removal unit to separate unreacted phenol therefrom. The obtained bisphenol A is led to a melt crystallizer to separate residual phenol and isomers therefrom. The separated phenol and isomers are cracked, and the thus recovered phenol is recycled to the reaction stage.
This process was proposed in consideration of the fact that in the production of bisphenol A, the filtrate from th
Ekawa Kenji
Isota Yoichiro
Nakaguchi Toru
Yao Kazuhiko
Honshu Chemical Industry Co. Ltd.
Merchant & Gould P.C.
Shippen Michael L.
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