Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1999-05-26
2001-07-17
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C422S186220
Reexamination Certificate
active
06262315
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process and apparatus for producing a dihydric phenolic compound. More particularly, the present invention relates to a process and apparatus for producing a dihydric phenolic compound at a high stability and safety, at a high selectivity and with a high efficiency.
Still more particularly, the present invention relates to a process and apparatus for producing a dihydric phenolic compound, for example, catechol or hydroquinone, from a monohydric phenolic compound at an excellent selectivity at a high stability, while containing the reaction liquid temperature of the monohydric phenolic compound in an appropriate range, which process and apparatus are suitable for industrial practice.
2. Description of the Related Art
Processes for producing a dihydric phenolic compound, for example, catechol together with hydroquinone by an oxidation reaction of monohydric phenolic compounds with peroxide compounds, for example, hydrogen peroxide and ketone peroxide, in the presence of specific catalysts are well known from, for example, Japanese Examined Patent Publications No. 52-38,546 (corresponding to U.S. Pat. No. 4,078,006), No. 52-38,547 (corresponding to U.S. Pat. No. 4,072,722), No. 52-38,548 and No. 52-38,549.
In the conventional processes for producing dihydric phenolic compounds, however, an industrial means for industrially and easily controlling the rapid temperature rise in the reaction liquid for the oxidation reaction of the monohydric phenolic compound due to the heat generated by reaction has not been concretely known. Therefore, the conventional processes are disadvantageous in that not only an explosion of ketoneperoxide contained in the reaction liquid cannot be surely prevented, but also the selectivity of the target dihydric phenolic compound significantly decreases due to the rapid rise of the reaction liquid temperature, and the yield of the dihydric phenolic compound decreases. Accordingly, when a high safety of the reaction procedure and a high selectivity of the target dihydric phenolic compound are required above all, the reaction procedure must be carried out at a low conversion of the monohydric phenolic compound.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process and apparatus for providing dihydric phenolic compounds by a continuous oxidation reaction of a monohydric phenolic compound, at enhanced selectivity and yield of the target dihydric phenolic compound, while preventing a rapid rise of the reaction liquid temperature due to a generation of heat of reaction and maintaining a conversion of the monohydric phenolic compound at a satisfactory level, which process and apparatus are suitable for industrial continuous production of the dihydric phenolic compounds.
The above-mentioned object can be attained by the process and apparatus of the present invention.
The process of the present invention for producing dihydric phenolic compound comprises oxidizing a monohydric phenolic compound in the presence of a catalyst by using a continuous multi-stage oxidation apparatus comprising a plurality of oxidation reactors connected to each other in series in such a manner that (1) in a first reactor of the oxidation apparatus, a monohydric phenolic compound having a temperature of 30 to 100° C., a peroxide compound and a catalyst are fed thereinto, to oxidize the monohydric phenolic compound into a dihydric phenolic compound, and the resultant reaction mixture containing the produced dihydric phenolic compounds, the non-reacted monohydric compound, the non-reacted peroxide compound and the catalyst is delivered from the first reactor; (2) the reaction mixture delivered from the first reactor is passed through one or more reactors succeeding to the first reactor, to further oxidize the non-reacted monohydric phenolic compound, while, in the steps (1) and (2), a portion of the peroxide compound is fed into the first reactor and the remaining portion of the peroxide compound is fed into at least one succeeding reactor; and (3) a final reaction mixture produced in a rearend reactor and comprising the produced dihydric phenolic compound, the non-reacted monohydric phenolic compound, the non-reacted peroxide compound and the catalyst is delivered from the oxidation apparatus.
In the dihydric phenolic compound-producing process of the present invention, optionally, at least one ketone compound is fed together with the monohydric phenolic compound, the peroxide compound and the catalyst into the first reactor.
In the dihydric phenolic compound-producing process of the present invention optionally, before the remaining portion of the peroxide compound is fed into at least one reactor succeeding to the first reactor, the reaction mixture delivered from a next reactor located in front of the succeeding reactor to which the remaining portion of the peroxide compound is fed is cooled to a temperature of 40 to 100° C. by a cooling means, and then is fed, together with the remaining portion of the peroxide compound, into the succeeding reactor, and the temperature of the reaction mixture passing through the oxidation apparatus is controlled to a level of 40 to 120° C.
The continuous multi-stage oxidation apparatus of the present invention for producing dihydric phenolic compounds by the process of the present invention as defined above, comprises a first reactor and one or more reactors succeeding the first reactor which reactors are connected to each other in series, and are each suitable for catalytically oxidizing a monohydric phenolic compound into dihydric phenolic compounds, wherein the first reactor is connected to a feed source of a monohydric phenolic compound, a feed source of a peroxide compound and a feed source of a catalyst, at least one succeeding reactor is connected to a feed source of the peroxide compound, and a rearend reactor has an outlet for delivering a final reaction mixture produced therein.
In the dihydric phenolic compound-producing apparatus of the present invention, optionally, the first reactor is further connected to a feed source of a ketone compound.
The dihydric phenolic compound-producing apparatus of the present invention optionally further comprises a cooling means arranged between the succeeding reactor connected to the peroxide compound-feed source and a next reactor located in front of the succeeding reactor connected to the peroxide compound-feed source.
REFERENCES:
patent: 3849502 (1974-11-01), Bourdin et al.
patent: 4072722 (1978-02-01), Umemura et al.
patent: 4078006 (1978-03-01), Umemura et al.
patent: 5493061 (1996-02-01), Ratnasamy et al.
patent: 2 064 497 (1970-12-01), None
patent: 50-142519 (1975-11-01), None
patent: 50-142518 (1975-11-01), None
European Search Report (1999).
Fujita Kazunori
Inaba Yukio
Kofuji Hiroshi
Burgess, Ryan & Wayne
R-Moran William
Shippen Michael L.
Ube Industries Ltd.
Wayne Milton J.
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