JPH0552816B2 - - Google Patents

Description

[Detailed description of the invention]

[Prior Art] Aliphatic hydrocarbons such as isobutane, 2-methylbutane, decahydronaphthalene, and cumene,
It is known that alkyl aromatic hydrocarbons such as methylnaphthalene and diisopropylbenzene give the corresponding hydroperoxides when oxidized with oxygen, in which case either the tert-carbon or the tert-aromatic carbon reacts. It is also known that the hydroperoxides give the corresponding phenols or alcohols as well as aldehydes or ketones in the presence of acidic catalysts. It is known that these methods are used to produce phenol from cumene, cresol from cymene, resorcinol from m-diisopropylbenzene, and hydroquinone from p-diisopropylbenzene. In previous methods, resorcinol and hydroquinone have been produced starting from pure and relatively expensive m- or p-diisopropylbenzene. [Problems to be Solved by the Invention] An object of the present invention is to provide a method for selectively producing hydroquinone from a relatively inexpensive hydrocarbon mixture. [Means for Solving the Problems] The object of the present invention is to provide a method for selectively producing hydroquinone from a hydrocarbon mixture obtained as a by-product of the cumene process, which method comprises a tert-alkyl aromatic hydrocarbon. Selectively oxidizing a mixed starting material consisting of one component and a hydroperoxide produced by an oxidation reaction of the alkyl aromatic hydrocarbon at 60 to 180°C in the presence of oxygen,
The dihydroperoxide of p-diisopropylbenzene (hereinafter referred to as p-diisopropylbenzene = dihydroperoxide) is separated from the reaction mixture, and then the peroxide is decomposed at 20 to 150°C using an acidic catalyst to produce hydroquinone. This is achieved by the manufacturing method of the invention. In the method of the present invention for selectively producing hydroquinone from a hydrocarbon mixture obtained as a by-product of cumene, the component containing tert-alkyl aromatic hydrocarbons is a boiling point
It is characterized by the use of a by-product which is a product at 170-220 °C and contains 10-80% by weight of diisopropylbenzene, 20-90% by weight of a _C4 - _C9 alkylbenzene mixture, and after oxidation, the reaction mixture is By cooling, p-diisopropylbenzene dihydroperoxide is selectively crystallized, and the separated peroxide is then decomposed into hydroquinone and acetone using an acidic catalyst, while monohydroperoxide and dihydroperoxide of m-diisopropylbenzene are decomposed using an acidic catalyst. Since peroxides remain in the oxidation reaction solution, a step is included to recycle them to the oxidation reactor. [Function] The method of the present invention is based on the knowledge that in oxygen oxidation reactions, the reactivity differs depending on the type of alkyl aromatic hydrocarbon, and the solubility of the obtained oxidation product also differs. Based on these findings, mixtures of alkyl aromatic hydrocarbons can also be used as starting materials for the reaction, and if the reaction conditions are optimally selected, only certain components of the mixed materials can be It has been found that it is possible to oxidize only the compound first. Furthermore, if a hydrocarbon mixture produced as a by-product in the cumene process is used as a starting material, p-diisopropylbenzene dihydroperoxide can be immediately crystallized to produce a It has also been found that it can be selectively separated from oxidation products. The dihydroperoxide is decomposed using an acidic catalyst to give hydroquinone. Suitable acidic catalysts include mineral acids such as sulfuric acid and phosphoric acid; acidic aluminosilicates; sulfur trioxide;
Examples include Lewis acids such as boron trifluoride and aluminum trichloride. However, in the method of the present invention,
A solid ion exchange resin containing acid groups is preferably used for the decomposition of dihydroperoxides, and since the acidic catalyst can be removed by filtration, an extra neutralization step can be omitted, and the sulfuric acid It will be more advantageous than the law. Suitable solvents used in the decomposition step are ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and/or low boiling aliphatic or aromatic hydrocarbons. Therefore, the method of the present invention utilizes the difference in reactivity in oxygen oxidation of alkyl aromatic hydrocarbons present in the by-product mixture obtained during cumene production, and also utilizes the difference in reactivity in oxygen oxidation of alkyl aromatic hydrocarbons present in the by-product mixture obtained during cumene production. It will be understood that the difference in solubility between the product and p-diisopropylbenzene dihydroperoxide is utilized. According to the method of the present invention, it is possible to initially oxidize only the tert-aralkyl compound by adjusting the reaction conditions, and it is also possible to selectively oxidize only p-diisopropylbenzene dihydroperoxide among the oxidation products. It can be precipitated. In this case, the other hydrocarbon components in the reaction mixture act as inert diluents. These inert diluents on the one hand promote the crystallization separation of p-diisopropylbenzene dihydroperoxide, and on the other hand act as slowing agents in the oxidation reaction and constitute optimal oxidation conditions for pure p-diisopropylbenzene. The reaction temperature is higher than the normal oxidation temperature 60~180℃
℃, preferably from 90 to 130°C, which results in rates comparable to the oxidation reaction rates of the pure individual feedstock components. Moreover, there are fewer by-products compared to oxidation reactions carried out at low temperatures. It is known that the oxidation reaction of diisopropylbenzene first gives the corresponding monohydroperoxide, and when the concentration of monohydroperoxide in the solution becomes sufficiently high (10% or more), the formation of dihydroperoxide begins. It is also known that this oxidation reaction can be catalytically promoted by adding the corresponding hydroperoxide to the raw material. Various hydroperoxides can be used as catalysts in the method of the invention. The most effective means from the viewpoint of dihydroperoxide production is to recirculate the mother liquor from which p-diisopropylbenzene dihydroperoxide has been separated to the oxidation reactor. This is because the mother liquor contains a large amount of diisopropylbenzene monohydroperoxide and a small amount of m-diisopropylbenzene monohydroperoxide, which further act as a catalyst. In the oxygen oxidation process, the total hydroperoxide concentration
Try to maintain it between 10 and 80% by weight, preferably between 20 and 80%. The circulation ratio of the mother liquor is 0.01 to 10:1, preferably 0.05 to 1, although it depends on the type of raw material.
The ratio is 2:1. Many methods are known for separating diisopropylbenzene dihydroperoxide from the mother liquor. For example, the dihydroperoxide can be extracted into a 4% sodium hydroxide solution so that it can be further transferred into methyl isopropyl ketone and sent to the decomposition step. Other methods include separating the dihydroperoxide using an anion exchange resin containing a base, or crystallizing and separating the dihydroperoxide as a sodium salt from the mother liquor, or adding an inert resin family or aromatic hydrocarbon to the mother liquor. and crystallize
It is known that dihydroperoxides can be separated by either of the following methods: In the method of the present invention, the step of crystallizing and separating diisopropylbenzene dihydroperoxide from the mother liquor can be carried out much more easily than the usual oxidation step of diisopropylbenzene. The reason for this is that raw materials often already contain about 50% hydrocarbons that function as inert agents. Moreover, under the conditions of the method of the present invention, m-diisopropylbenzene dihydroperoxide produced in the oxidation step does not crystallize, unlike in conventional methods. Therefore, the method of the invention is particularly suitable for p-
It is selective with respect to the separation of diisopropylbenzene dihydroperoxide, and for this reason the process of the invention has the additional feature that the hydroquinone obtained by acid decomposition is almost free of phenolic impurities. In the method of the present invention, p-
The by-product containing about 25% diisopropylbenzene is oxidized at 60-180°C, preferably 90-100°C, such that the total hydroperoxide concentration is 10-80% by weight, preferably 20-60% by weight. .
The produced p-diisopropylbenzene dihydroperoxide is cooled and crystallized and separated from the mother liquor. The mother liquor is recycled to the oxidation reactor and the ratio to starting material is from 0.01 to 10:1, preferably from 0.25 to
Make sure the ratio is 2:1. The crystallized p-diisopropylbenzene dihydroperoxide is dissolved in methyl isobutyl ketone and heated at 20-150°C using an acidic catalyst, preferably an acidic ion exchange resin.
It is preferably decomposed at 20 to 120°C to produce hydroquinone. [Examples] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples unless it departs from the gist of the present invention. Examples 1 to 5 A cylindrical oxidation reactor (45 mm in diameter and 450 mm in height) equipped with a heating jacket, a thermometer, an oxygen dispersion tube, and an oxygen flowmeter was charged with 500 ml of the by-product hydrocarbon of the cumene process. The composition of the by-product hydrocarbons is shown in Table 1. The hydrocarbon mixture was heated to 100° C. and then oxygen was fed into the reactor at a constant rate of 330 ml/min through an oxygen dispersion tube. After 12.5 hours of oxidation, the total peroxide concentration of the solution was 1.1%. The reaction product was diluted with starting materials to give a total hydroperoxide concentration of 5.0% in the mixture. The mixture was oxidized for 24.5 hours to give a total hydroperoxide concentration of 14.4%. Table 1 shows the oxidation products when the concentration of hydroperoxide catalyst in the starting material is 0.9 or 4.5% by weight or when the reaction temperature is 90°C. Table Component content (wt%) Isopropylbenzene 1.342 tert-butylbenzene 3.771 sec-butylbenzene 0.9672 2-phenyl-3-methylbutane 0.352 2-methyl-2-phenylbutane 2.608 1-phenyl-1-methylbutane 0.403 1,3- Diisopropylbenzene 21.379 i-hexylbenzene 7.606 1,4-diisopropylbenzene 25.942 2-methyl-2-phenylpentane 8.647 n-hexylbenzene 1.579 3-phenylhexane 5.810 2-phenylhexane 2.245 1-methyl-1-phenyl Hexane 0.491 1-Propyl-1-phenylhexane 1,1-dimethyl-1-phenylhexane 1-ethyl-1-phenylhexane 0.611

[Table] Examples 6 to 10 A hydrocarbon mixture having the composition shown in the table was heated to 110°C in the same manner as described in Examples 1 to 5.
oxidized with oxygen. The partially oxidized mother liquor was circulated as a catalyst for the oxidation reaction so that the total hydroperoxide concentration in the starting material was (0.9), (2.4), (4.9), (7.6) and (5.1)%, respectively. did. The oxidation products produced are shown in Table 1.

Table (a) to (c) are the same as Examples 1 to 5 Solid reaction products were precipitated from the reaction mixtures described in Examples 4 and 8 to 10 by cooling.
Its composition is p-DHP (65-75%), p-HHP (20
~30%) and m-DHP (0-5%). The precipitate was dissolved in methyl isobutyl ketone to give a
A 10% solution was prepared and the hydroperoxide was converted to the corresponding phenol using either sulfuric acid or an acidic ion exchange resin "Amberlyst H+" (trade name) in the manner described in Examples 11-15. The decomposition temperature was 60°C and the time was 20 minutes. The results are shown in Table 1.

[Table] [Effects of the Invention] The advantage of the method of the present invention for selectively producing hydroquinone from the hydrocarbon mixture produced as a by-product in the cumene method compared to the conventional method is that, first, the expensive pure p- The point is that diisopropylbenzene is not used as a starting material. Furthermore, the by-products obtained by the cumene process do not require any purification prior to use, and the intermediate product p-diisopropylbenzene dihydroperoxide can be separated from other oxidation products simply by crystallization; As a result, it is possible to produce hydroquinone containing almost no phenolic impurities. Furthermore, since the method of the present invention uses an acidic ion exchange resin as a decomposition catalyst, an extra neutralization step is not required, and the process is significantly simplified.

Claims (1)

[Scope of Claims] 1. A tert-alkyl aromatic hydrocarbon-containing component;
A mixed starting material consisting of a hydroperoxide-containing component produced in the oxidation reaction of an alkyl aromatic hydrocarbon is selectively oxidized with oxygen at 60 to 180°C, and then dihydroperoxide of p-diisopropylbenzene is separated from the mixture. In the manufacturing method in which hydroquinone is produced by decomposing it at 20 to 150°C using an acidic catalyst, the boiling point of the cumene process is as a by-product as a tert-alkyl aromatic hydrocarbon-containing component.
A by-product containing a mixture of 10-80% by weight of diisopropylbenzene and 20-90% by weight of _C4 - _C9 alkylbenzene is used at 170-220°C, and the oxidation reaction product is After cooling, the dihydroperoxide of p-diisopropylbenzene is selectively crystallized, the crystals are separated, and the crystals are decomposed with an acidic catalyst to form hydroquinone and acetone, while the monohydroperoxide of m-diisopropylbenzene and A production method characterized by leaving the dihydroperoxide remaining in the oxidation solution and circulating it to the oxidation reactor. 2 The components produced by the cumene process are 10 to 80% by weight of diisopropylbenzene, tert-butylbenzene, 1,1-dimethylpropylbenzene, i- and 1-hexylbenzene, and 2- and 3-phenylhexane. The method according to claim 1, characterized in that the mixture contains 20 to 60% by weight. 3. The manufacturing method according to claim 1 or 2, characterized in that dihydroperoxide of p-diisopropylbenzene is decomposed into hydroquinone using an acidic ion exchange resin. 4. The production method according to any one of claims 1 to 3, characterized in that the ratio of the oxidation reaction mixture to the starting material recycled to the oxidation reactor is in the range of 0.01 to 10:1.