Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-02-12
2002-08-13
Shippen, Michael L (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S754000, C568S798000
Reexamination Certificate
active
06433232
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for producing a hydroxyaromatic compound. In more particular, the invention relates to a process for producing a hydroxyaromatic compound which makes it possible to produce a hydroxyaromatic compound in a high yield.
BACKGROUND OF THE INVENTION
For producing a hydroxyaromatic compound (intended product) such as resorcinol from an alkyl group-substituted aromatic hydrocarbon (starting material) such as 1,3-diisopropylbenzene, there is known, for example, a process comprising the steps of:
(1) oxidizing a starting material liquid containing an alkyl group-substituted aromatic hydrocarbon to obtain a reaction liquid containing a hydroperoxyaromatic compound,
(2) decomposing the hydroperoxyaromatic compound in the presence of an acidic substance to obtain a reaction mixture containing a hydroxyaromatic compound, and
(3) distilling the reaction mixture to separate the hydroxyaromatic compound from light boiling fractions, thereby to obtain the hydroxyaromatic compound.
However, this process has a disadvantage in that a large amount of heavy substances are by-produced in step (3), resulting in lowering the yield of the intended hydroxyaromatic compound.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a process for producing a hydroxyaromatic compound which can suppress the above-mentioned by-production of heavy substances and resultantly makes it possible to produce the intended hydroxyaromatic compound in a high yield.
The present inventor has made extensive study to find a process for producing hydroxyaromatic compounds which is free from the above-mentioned disadvantage. As a result, he has found that the above-mentioned object of the present invention can be attained by neutralizing the reaction mixture obtained in the above step (2) under specific conditions to obtain a neutralized mixture, separating the neutralized mixture into an oil layer and an aqueous layer, and distilling the oil layer thus separated. The present invention has been accomplished on the basis of the above finding.
Thus, the present invention provides a process for producing a hydroxyaromatic compound comprising the steps of:
(i) oxidizing a starting material liquid containing an alkyl group-substituted aromatic hydrocarbon to obtain a reaction liquid containing a hydroperoxyaromatic compound,
(ii) decomposing the hydroperoxyaromatic compound in the presence of an acidic substance to obtain a reaction mixture containing a hydroxyaromatic compound,
(iii) neutralizing the reaction mixture with an aqueous alkali solution to obtain a neutralized mixture so that an aqueous layer, which is obtained by mixing an oil layer of the neutralized mixture and deionized water in a volume ratio of the oil layer to the deionized water of 2:1 to obtain an oil/water mixture and allowing the oil/water mixture to stand still, may have a pH falling within the range of from 4.5 to 5.5,
(iv) separating the neutralized mixture into an oil layer and an aqueous layer to obtain an oil layer, and
(v) distilling the oil layer to separate the hydroxyaromatic compound from light boiling fractions, thereby to obtain the hydroxyaromatic compound.
DETAILED DESCRIPTION OF THE INVENTION
The “alkyl group-substituted aromatic hydrocarbon” referred to in the present invention signifies an aromatic hydrocarbon substituted with at least one C
1-10
primary, secondary or tertiary alkyl group. The number of the substituent alkyl groups that the aromatic hydrocarbon may have is not particularly limited, but is preferably 1-3. The alkyl group includes, for example, methyl group, ethyl group and isopropyl group. Of these, ethyl group and a secondary or tertiary alkyl group such as the isopropyl group are preferable. The alkyl group-substituted aromatic hydrocarbons include, for example, methylbenzene, ethylbenzene, isopropylbenzene, 1,3-diisopropylbenzene and 1-methyl-3-isopropylbenzene. Of these, ethylbenzene, isopropylbenzene, 1,3-diisopropylbenzene and 1-methyl-3-isopropylbenzene are preferable.
The “hydroperoxyaromatic compound” referred to in the present invention signifies hydroperoxides obtainable by oxidizing alkyl group-substituted aromatic hydrocarbons. When 1,3-diisopropylbenzene is selected as an alkyl group-substituted aromatic hydrocarbon, representative hydroperoxyaromatic compounds obtainable therefrom are as follows.
MHPO: 3-isopropyl-1-(2-hydroperoxy-2-propyl)-benzene,
DHPO: 1,3-di(2-hydroperoxy-2-propyl)benzene,
CHPO: 3-(2-hydroxy-2-propyl)-1-(2-hydroperoxy-2-propyl)benzene.
The methods and conditions used for oxidizing the alkyl group-substituted aromatic hydrocarbon are not particularly limited. A method of oxidation can be, for example, a known one in which oxidation is carried out with oxygen or air. Any known conditions for oxidation can be used. When 1,3-diisopropylbenzene is selected as an alkyl group-substituted aromatic hydrocarbon, for example, it is usually oxidized under the conditions of a temperature of 70-110° C., a pressure of 0-1 MPa (G) and a residence time of 0-50 hours. The reactor includes, for example, a flow-through reaction vessel and reaction tower. The production of a hydroxyaromatic compound is usually conducted by a continuous process, wherein the starting material liquid often contains a recycled liquid containing hydroperoxides and unreacted 1,3-diisopropylbenzene, so that the starting material liquid usually contains the following main components (the weight of the starting material liquid being taken as 100% by weight).
1,3-diisopropylbenzene
10-40% by weight
MHPO
20-60% by weight
DHPO
0-5% by weight
CHPO
0-10% by weight
The reaction liquid obtained by the oxidation of the starting material liquid with air usually contains the following main components (the weight of the reaction liquid being taken as 100% by weight).
1,3-diisopropylbenzene
10-40% by weight
MHPO
20-60% by weight
DHPO
3-30% by weight
CHPO
0-10% by weight
It is possible to obtain the intended hydroperoxy aromatic compound exclusively from this reaction liquid by means of extraction with a solvent etc.
The “hydroxyaromatic compound” referred to in the present invention signifies the intended product obtained by the process comprising the steps (1)-(3) above. When 1,3-diisopropylbenzene is selected as an alkyl group-substituted aromatic hydrocarbon and DHPO is selected as an hydroperoxy aromatic compound, for example, the hydroxyaromatic compound corresponding thereto is resorcinol. In this case, besides resorcinol of the intended product, acetone can be obtained as a by-product.
The “acidic substance” referred to in the present invention signifies a substance which has an effect of decomposing a hydroperoxyaromatic compound into a hydroxyaromatic compound. The kind of the acidic substance is not particularly limited. The acidic substance includes, for example, mineral acids, such as sulfuric acid, sulfuric anhydride, sulfur dioxide, perchloric acid, phosphoric acid, polyphosphoric acid, hydrochloric acid, hydrogen fluoride, phosphotungstic acid and phosphomolybdic acid; sulfonic acids, such as benzenesulfonic acids (e.g., p-toluenesulfonic acid), methanesulfonic acid, trichloromethanesulfonic acid and trifluoromethanesulfonic acid; Lewis acids, such as aluminum chloride, boron trifluoride, boron trifluoride complex, tin chloride, antimony chloride and sulfur tetrafluoride; organic acids, such as trichloroacetic acid, trifluroacetic acid and chloroacetic acid. Preferred acidic substances among these are sulfuric acid, sulfuric anhydride, perchloric acid, boron trifluoride and phosphoric acid.
The conditions in the decomposition by the acidic substance are not particularly limited. For example, when sulfuric anhydride is used as the acidic substance, it is preferable that the molar ratio of the acidic substance used to the hydroperoxide group is not more than 0.003, the temperature is 50-150° C. and the reaction time is not more than 15 minutes.
Step (iii) according to the present invention is a step of neutralizing the react
Shippen Michael L
Sumitomo Chemical Company Limited
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