JPS6348254B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing phloroglucin by acid decomposition of 1,3,5-triisopropylbenzene trihydroperoxide (hereinafter abbreviated as THP). More details: 1,3,5-triisopropylbenzene (hereinafter abbreviated as TIPB)
THP containing oxidized by-products obtained by the oxidation of
Using a heteropolyacid as an acid decomposition catalyst, approximately 40
At a temperature of from about 110°C to about 110°C, the acid decomposition rate is from about 92 to about
The present invention relates to a method for producing phloroglucin in high yield by carrying out an acid decomposition reaction in a range of 99.5%. It has been attempted in the past to oxidize TIPB to THP and further acid decompose it to produce phloroglucin; for example, East German Patent No. 12239, J. fu¨r prakt Chem 4 , 273, or the British patent. It is disclosed in the specification of No. 751598, etc. However, the selectivity towards THP during oxidation of TIPB is low;
Numerous other by-products of THP are produced. Also THP
Hydrochloric acid, perchloric acid, etc. are used as acid decomposition catalysts, but these acid decomposition catalysts have a slow decomposition reaction rate, and when a large amount of acid decomposition catalysts are used, the amount of by-products such as tar increases, which leads to The yield of phloroglucin is also low. On the other hand, JP-A-52-5719 discloses a method for producing phenol or hydroquinone by acid decomposing the corresponding hydroperoxide in the presence of a heteropolyacid such as tungstosilicic acid. Although this heteropolyacid differs depending on the reaction solvent, it has generally high solubility and can be used as a liquid catalyst, and has superior performance in terms of decomposition rate and selectivity compared to other inorganic acids such as sulfuric acid. are doing. On the other hand, in the case of phloroglucin, it is generally difficult to separate THP from the oxidation product of TIPB, so the oxidation product of TIPB is directly brought into contact with an acid decomposition catalyst to perform acid decomposition, and then phloroglucin is separated and recovered. is an industrially desirable method. However, as a by-product in the oxidation products of TIPB, (Monocarbinol dihydroperoxide
MHP) (dicarbinol monohydroperoxide
DHP) (tricarbinol TC), and other bifunctional oxidation products.

【formula】

【formula】

[Formula] etc., and as a monofunctional oxidation product

【formula】

[Formula] etc. Even if the oxidation reaction products containing these by-products are slowly acid-decomposed using the above-mentioned heteropolyacid with excellent performance, MHP, DHP, and
Side reactions between carbinol group-containing byproducts such as TC and phloroglucin produce high-boiling products, resulting in a low yield of phloroglucin. For this reason, the present inventors investigated the acid decomposition reaction of THP containing oxidation byproducts obtained by oxidation of TIPB, and found that even in the coexistence of oxidation byproducts, a heteropolyacid is used as an acid decomposition catalyst, and The present invention was achieved by discovering that phloroglucin can be obtained in high yield by carrying out an acid decomposition reaction under specific reaction conditions. That is, the present invention provides THP containing by-products obtained by acid decomposition of TIPB, as an acid decomposition catalyst.
The present invention relates to a method for producing phloroglucin, which is characterized by using a heteropolyacid and carrying out acid decomposition at a temperature of about 40 to about 110°C with an acid decomposition rate in the range of about 92 to about 99.5%. As a method for oxidizing TIPB, the method disclosed in the above-mentioned known documents or the method disclosed in the patent application filed by the present applicant in 1982-
Examples include the method disclosed in No. 31778. Usually, TIPB is oxidized with molecular oxygen-containing gas in the presence of a radical initiator and aqueous alkaline solution as necessary, or it is further oxidized by contacting it with hydrogen peroxide or other oxidation catalysts. be done. Usually, TIPB is oxidized with molecular oxygen-containing gas in the presence of a radical initiator and aqueous alkaline solution as necessary, or it is further oxidized by contacting it with hydrogen peroxide or other oxidation catalysts. be done. The oxidation products obtained by these oxidations are
After removing the oxidation catalyst as necessary, it is subjected to acid decomposition. Heteropolyacids used in acid decomposition include, for example, the compounds disclosed in JP-A-52-5719, and generally contain atoms of phosphorus, silicon, boron, arsenic, tellurium, aluminum, germanium, etc. and other It is a relatively high molecular weight inorganic compound composed of metal oxides such as oxides of tungsten, molybdenum, vanadium, chromium, and niobium. More specifically, the heteropolyacids include molybdophosphoric acid, molybdosilicic acid, molybdoboric acid, molybdoarsenic acid, molybdotelluric acid, molybdoalumic acid, molybdogermanic acid, tungstophosphoric acid, tungstosilicic acid, tungstoboric acid, tungstoarsenic acid, tungst Telluric acid, tungstoalumic acid, tungstogermanic acid, tungstotitanic acid, tungstostannic acid, vanadophosphoric acid,
Examples include vanadosilicic acid, among which molybdophosphoric acid, molybdosilicic acid, tungstophosphoric acid, and tungstosilicic acid are preferably used. One or two types of heteropolyacids may be used as necessary.
More than one type is used, and it is usually desirable to dilute it with a diluent, preferably water, lower alcohol, or lower alcohol. In this case, the concentration of the heteropolyacid is usually about 0.001 to about 3000 mmol/
, preferably about 0.01 to about 300 mmol/
It is used to a certain extent. The proportion of the heteropolyacid used is usually about 1.5% relative to the oxidation reaction product subjected to acid decomposition. 0005 to about 10% by weight, preferably about 0.005 to about 3% by weight. The acid decomposition of the present invention is preferably carried out in a homogeneous reaction system. Therefore, it is desirable to perform acid decomposition in the presence of a solvent that dissolves both the oxidation reaction product and the heteropolyacid. Examples of solvents include monoketones having 3 to 16 carbon atoms such as acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone; ethers such as diethyl ether, diisopropyl ether, and anisole; methanol, ethanol, propanol, butanol, octanol, and - Alkyl alcohols having 1 to 8 carbon atoms such as ethylhexyl alcohol, or together with these, alcohols having 6 carbon atoms such as benzene, toluene, xylene, ethylbenzene, cumene, cymene, diisopropylbenzene, etc.
It is desirable to use a mixed solvent with 1 to 12 aromatic hydrocarbons. In the present invention, monoketones, mixed solvents of monoketones and aromatic hydrocarbons, or mixed solvents of monoketones, alkyl alcohols, and aromatic hydrocarbons are particularly suitable. The acid decomposition of the present invention is performed to reduce the mixture containing the above components to about
The reaction is carried out by heating to 40°C to about 110°C, particularly preferably about 50°C to about 100°C, and particularly preferably under reflux conditions. If the reaction temperature is less than 40°C, the reaction will be slow and in order to obtain the desired acid decomposition rate, a long reaction time or a large amount of catalyst will be required, which is not only economically disadvantageous, but also the desired acid decomposition rate cannot be achieved by these means. Even if the reaction is carried out to the extent of decomposition, the yield of phloroglucin does not improve because the rate of concurrent side reactions increases. When the reaction temperature exceeds 110°C, thermal decomposition of hydroperoxides occurs at a considerable rate, resulting in a large amount of high-boiling point impurities being produced as by-products, resulting in a decrease in the yield of phloroglucin. In the acid decomposition of the present invention, the acid decomposition rate is about 92 to about
It is carried out until it reaches the range of 99.5 equivalent %. The acid decomposition rate here refers to the degree of decrease in the hydroperoxide concentration before and after acid decomposition in terms of equivalent percentage, and is a value calculated by the following method. Acid decomposition rate = {1-C ₂ × W ₂ / C ₁ × W ₁ } × 100 where C ₁ ; Hydroperoxide concentration in the raw material oxidation product determined by iodometry (gram equivalent/g) W ₁ ; Acid Weight of raw material oxidation product subjected to decomposition reaction (g) C ₂ ; Hydroperoxide concentration in acid decomposition reaction product determined by iodometry (gram equivalent/g) W ₂ ; Weight of acid decomposition reaction product ( g) In addition, when carrying out the reaction in a continuous manner,
W ₁ and W ₂ indicate the respective weights per unit time. If the acid decomposition is terminated at a stage where the acid decomposition rate is lower than about 92% by weight, not only will the yield of phloroglucin decrease, but also abnormal reactions will easily occur during the subsequent separation and recovery of phloroglucin, which is operationally dangerous. Furthermore, if acid decomposition is carried out until the acid decomposition rate is higher than about 99.5% by weight, secondary reactions between the generated phloroglucin and ketones or by-produced olefins will increase, so the yield of phloroglucin will increase. The color of the phloroglucin decreases and its hue deteriorates, making it difficult to obtain highly pure phloroglucin using conventional purification methods. Therefore, in the present invention, it is necessary to maintain the acid decomposition rate within the above range, and it is particularly desirable to maintain the acid decomposition rate within the range of about 94 to about 99 equivalent %. From the acid decomposition reaction mixture obtained by acid decomposition, phloroglucin is separated and recovered according to a conventional method. For example, acetone and the solvent are distilled off and concentrated from the acid decomposition reaction mixture, and phloroglucin is separated and recovered by operations such as extraction, distillation, or crystallization. According to the present invention, phloroglucin can be obtained in high yield. Examples are shown below. Reference example 1 (1) 100 parts by weight of 1,3,5-TIPB (95% purity)
and 10 parts by weight of a 4.5% by weight NaOH aqueous solution was oxidized for 30 hours at a pressure of 6.6 kg/cm ² and a temperature of 100° C. while stirring and blowing air.
At that time, a 4.5% by weight NaOH aqueous solution was intermittently fed into the reaction system so as to maintain the pH of the aqueous layer within the reaction system at 8 to 10. After the oxidation was completed, 850 parts by weight of a 1-octanol/toluene mixed solvent (1-octanol/toluene weight ratio was 4/6) was added, and the separated water layer was removed to obtain 1000 parts by weight of an oil layer. 20% by weight _H2O2 in _this oil layer (1000 parts by weight)
500 parts by weight of an aqueous solution containing 15% by weight of sulfuric acid were added thereto, and the reaction was carried out at a temperature of 50°C for 25 minutes with stirring. After the reaction was completed, the separated aqueous layer was removed, and the oil layer was neutralized, washed with water, and azeotropically dehydrated to obtain 1002 parts of an oil layer having the composition shown in Table 1. Example 1 The oil obtained in Reference Example 1 was heated at a rate of 100 parts by weight/hr.
and acetone containing 0.12% by weight of tungstophosphoric acid were each fed at a rate of 100 parts by weight/hr into a reactor equipped with a stirrer, a reflux condenser, and a reaction liquid outlet, and the average reaction temperature was 68°C under stirring. The acid decomposition reaction was carried out while withdrawing the reaction liquid so that the residence time was 30 minutes. The concentration of phloroglucin in the acid decomposition reaction product was 2.3% by weight, and the yield of phloroglucin from 1,3,5-THP was equivalent to 90 mol%. The concentration of unreacted hydroperoxide in the reaction product is
The acid decomposition rate is 0.021 milligram equivalent/g.
This corresponded to 97.5%.

[Table] Examples 2 to 4 1,3,5-
Acid decomposition reaction of TIPB oxidation product was carried out. Table 2 shows the type of catalyst, the amount used, and the reaction results.

[Table] Examples 5 and 6, Comparative Examples 1 and 2 1.
Acid decomposition reactions of 3,5-TIPB oxidation products were carried out. Table 3 shows the amount of catalyst used and the reaction results.

【table】

[Claims]

1 In a reaction system having a fractionating column installed above, in the presence of an organoaluminum compound, the following formula (R ¹ and R ² and the dotted line in the formula have the meanings given below) and the unsaturated alcohol of the following formula (R ³ in the formula means an alkyl group having 1 to 4 carbon atoms) with acetoacetic acid alkyl ester is eliminated by reaction with the following formula R ³ -OH ()