Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1998-02-24
2002-02-26
Wilson, James O. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S741000, C568S768000, C568S803000
Reexamination Certificate
active
06350921
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved process for the continuous simultaneous production of dihydroxybenzene (DHB) and diisopropylbenzene dicarbinol (DCL) from diisopropylbenzene. More specifically, this process includes the steps of: oxidizing diisopropylbenzene to obtain an oxidate comprising, among other things, diisopropylbenzene dihydroperoxide (DBP) and diisopropylbenzene hydroxyhydroperoxide (HHP); extracting DHP and HHP from the oxidate into an aqueous caustic solution using a Karr Column operation; continuously and simultaneously isolating HHP and DHP into separate fractions from the caustic solution by using Karr Column cold and hot methyl isobutyl ketone (MIBK) extractions; producing dihydroxybenzene by the cleavage of the DHP extract fraction in the presence of an acid catalyst; and producing dicarbinol by decomposing the HHP fraction under atmospheric conditions using an aqueous alkaline solution.
BACKGROUND OF THE INVENTION
It is known in the art that hydroperoxides, such as diisopropylbenzene dihydroperoxide (DHP), diisopropylbenzene monohydroperoxide (MHP), and diisopropylbenzene hydroxyhydroperoxide (HHP), can be produced by oxidizing diisopropylbenzenes with molecular oxygen either in the presence or absence of base catalysts. The continuous oxidation and production of diisopropylbenzene dihydroperoxide from the diisopropylbenzenes in the presence of a strong base, such as sodium hydroxide, are disclosed, for example, in British Patent No. 727,498 and U.S. Pat. No. 3,953, 521. These patents disclose that m- and p-diisopropylbenzene dihydroperoxides can be continuously isolated from the diisopropylbenzene oxidation mixture by caustic extraction, and that continuous oxidation of diisopropylbenzenes for the production of dihydroperoxides can be achieved by maintaining the pH in a range of between 8 and 11 and the temperature at about 85-95° C. in the oxidation reactor. British Patent No. 727,498, as well as U.S. Pat. No. 2,856,432, also disclose that the dihydroperoxides (DHP) present in the diisopropylbenzene oxidation mixture can be effectively separated by means of 4-8 wt. % caustic solutions. In addition to dihydroperoxide (DHP), part of the hydroxyhydroperoxide (HHP) present in the oxidation material is also extracted into the caustic solution.
U.S. Pat. No. 4,237,319 also discloses a method for the batch production of m-diisopropylbenzene dihydroperoxide (m-DHP) by oxidizing m-diisopropylbenzene under alkaline conditions.
Extraction of DBP into the caustic solution, as described in the above art, can be followed by isolation of the DHP for the production of a dihydric phenol, such as resorcinol or hydroquinone, in several ways. Of these methods, a preferred method in the art is to extract the DHP from the caustic solution into an organic solvent, preferably MIBK. Using this solvent, a temperature of 70-80° C. and contact times of 5-10 minutes, it is possible to extract a high proportion of the DHP into MIBK with negligible losses by decomposition. British Patent No. 921,557 discloses that m-DHP present in the aqueous caustic solution is extracted by the MIBK solvent at 75° C. In order to improve the extraction efficiency, U.S. Pat. No. 3,932,528 discloses that by adding about 1% ammonia into an aqueous 8% caustic soda solution containing 12.3% DHP, MIBK solvent is more effective at 60° C. for DHP extraction through three counter-current contact stages.
U.S. Pat. No. 4,059,637 describes a method by which DHP present in the caustic solution is extracted using MIBK solvent in a four-stage countercurrent mixer settler-type extraction. The caustic solution containing DHP used in the mixer settler-type extraction is previously treated with MIBK at a temperature of below 30° C. to remove oxidation by-products having 2-hydroxy-2-propyl group such as diisopropylbenzene hydroxyhydroperoxide (HHP) and diisopropylbenzene dicarbinol (DCL). The HHP content of the caustic solution containing DHP prior to feed into the mixer-settler extraction is reported to be about 4.2%. After the extraction, the purity of DHP in the MIBK solution is reported to be 93%.
Several patents disclose different acid type catalysts and temperatures to obtain a dihydric phenol such as resorcinol or hydroquinone from the DHP by cleavage. For example, British Patent No. 743,736 discloses sulfuric acid as the catalyst for m-DHP cleavage in the presence of an MIBK solvent under reflux conditions. With a residence time of between about 7.5-10 minutes and a 0.2 wt. % H
2
SO
4
catalyst, 99.6% of the DHP is decomposed. British Patent No. 819,450 discloses a sulfur trioxide catalyst for the cleavage of m-DHP; sulfur trioxide is reported as causing a far more rapid cleavage reaction than the corresponding quantity of sulfuric acid. The decomposition of m-DHP is carried out continuously in two reactors connected in series, using MIBK and acetone as the solvents employed in the cleavage operation. Canadian Patent No. 586,534 also discloses the use of a sulfur trioxide catalyst for cleaving m-DHP in the presence of 0.3 wt. % water in the cleavage reaction. U.S. Pat. No. 3,923,908 discloses a process for cleaving diisopropylbenzene dihydroperoxides in the presence of impurities such as isopropylphenyl dimethylcarbinol (MCL), diisopropylbenzene hydroxyhydroperoxide (HHP) and diisopropylbenzene dicarbinol (DCL) using a sulfur trioxide catalyst and a solvent.
In order to effectively utilize the by-product diisopropylbenzene hydroxyhydroperoxide (HHP), Japanese Patent Application 95-304027 and Japanese Patent Application No. 95-301055 disclose a method by which an MIBK solution containing HHP is reduced by hydrogen in the presence of a palladium-alumina catalyst (a material carrying 1 wt. % of palladium metal) in an autoclave equipped with an agitator, at a hydrogen pressure of 6 atmospheres and a reaction temperature of 90° C., to obtain diisopropylbenzene dicarbinol (DCL). Though this method produces DCL from HHP, the safety of this process is questionable, as it involves handling high pressure hydrogen in the presence of a highly volatile solvent (MIBK) at high temperatures.
One important aspect recognized in the art of producing high purity dihydric phenol by the hydroperoxidation technology is to prepare a high purity cleavage feed (DHP) from the diisopropylbenzene oxidation mixture. Although DHP is produced in the DIPB oxidation, it may not be easy to completely remove the DHP from the oxidation mixture for use in the cleavage step of the hydroperoxidation process. In a standard first step of DHP separation from the oxidate, caustic extraction is typically performed using either a 4% or 8% NaOH solution. During this extraction, DHP as well as other impurities present in the oxidate, such as HHP, acetyl-isopropylbenzene hydroperoxide (KHP), MHP, etc., are extracted. When an 8% NaOH solution is used, about 90-95% of the HHP and KHP present in the oxidation mixture are known to be extracted into the caustic solution, along with about 1-2% MHP. MHP present in the caustic solution is back extracted with a DIPB solvent. The solution comprising the DIPB, extracted MHP and other extracted oxidation impurities can then be recycled to the oxidation reaction and subjected to oxidation. This DIPB extraction does not have much effect on removing other impurities such as HHP and KHP from the caustic extract solution, however. To remove the HHP from the caustic solution, an MIBK solvent extraction is typically done at a low temperature. In spite of this operation, the concentration of HHP in the caustic solution before the final MIBK extraction can still be relatively high and, therefore, this method has been found to be a difficult route to produce a very high purity DHP for the cleavage. None of the patents or other literature in the art suggest or disclose what happens to impurities such as KHP present in the caustic extract. If the extraction procedures or methods are not efficient, then the hydroperoxidation process impurities are expected to interfere with the isolation of a very high
Durairaj Raj B.
Romell Vaughn J.
Tackie Michael N.
Volek Thomas K.
Anderson Debra Z.
Eckert Seamans Cherin & Mellott , LLC
Indspec Chemical Corporation
Meyers Diane R.
Owens, Jr. Howard V.
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