JPS647976B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing cyclic alcohols, and more specifically, when producing a cyclic alcohol by catalytically hydrating a cyclic olefin or a cyclic olefin-containing hydrocarbon mixture,
The present invention relates to a method for obtaining cyclic alcohols in high yield by using a mixture of a heteropolyacid and an aromatic sulfonic acid as a catalyst. Conventionally, methods for producing cyclohexanol by hydrating cyclic olefins, especially cyclohexene, have been carried out using various catalysts, such as methods in which esters are formed using high concentration sulfuric acid and then hydrolyzed, and phosphoric acid. A method of hydration using a solid catalyst supported on a carrier, a method of using a cation exchange resin as a solid catalyst (Japanese Patent Publication No. 38-15619, Japanese Patent Publication No. 44-26656), or an aromatic sulfonic acid Methods using catalysts (Japanese Patent Publication No. 43-8104, Japanese Patent Publication No. 43-16125) are known. However, the method of using high-concentration sulfuric acid to convert it into esters and then hydrolyzing them is not economical because it requires a large amount of money to recover the high-concentration sulfuric acid, and there are problems with corrosion of the equipment material. If benzene is contained in cyclohexene, a large amount of by-products will be produced by the reaction between benzene and sulfuric acid, so this method has the disadvantage that it cannot be used for mixed systems with benzene. . In addition, methods using solid catalysts such as phosphoric acid supported on a carrier have low yields, and there are problems with the life of the catalyst due to the elution of the supported acid. Methods using resins have the disadvantage that the catalyst has low heat resistance, the reaction temperature cannot be raised too high to avoid decomposition or collapse of the resin, and the reaction rate is extremely slow. Furthermore, methods using aromatic sulfonic acid catalysts have the disadvantage of low catalytic activity, with the best one-pass conversion rate being 30% and the others being less than 20%, as seen in the examples. . By the way, in general, in the hydration of olefin,
A method using an aqueous solution of a heteropolyacid such as silicotungstic acid, phosphomolybdic acid, or phosphotungstic acid is known (Brennestoff Chem., 38 ,
321, 375 (1957), etc.). However, with respect to this method, no report has been found so far that provides results that are fully satisfactory in all respects. For example, in Japanese Patent Publication No. 49-36203, Japanese Patent Publication No. 50-35052, and Japanese Patent Publication No. 50-35053, the concentration of heteropolyacid is made relatively low in order to suppress corrosion and side reactions of equipment materials, and Add alkali etc. to adjust pH to 2.5 to 4.5
However, in this case, the one-pass conversion rate is extremely low, such as a few percent. Furthermore, in Japanese Patent Application Laid-Open No. 51-13711,
By using a highly concentrated aqueous solution of heteropolyacid of 10 to 70% by weight and performing the reaction at a temperature of 100 to 170°C, side reactions such as corrosion of materials and the formation of olefin polymers can be suppressed, and the life of the catalyst can be reduced. It is stated that the activity is satisfactory. However, in actual examples, only α-olefins such as ethylene and propylene are used as raw materials for the hydration reaction, and olefins with internal double bonds such as 2-butene and cyclohexene are not used. do not have. In addition, as an example of increasing the concentration of the alcohol produced in the heteropolyacid by increasing the concentration of the heteropolyacid, the raw material for hydration is a long-chain α-olefin with relatively low hydration activity. An example is given using octene-1, but in this case the concentration of the hydration product octanol in the heteropolyacid is very low. Therefore, it is expected that the hydration activity for olefins having an internal unsaturated bond, such as 2-butene, 2-octene, and cyclohexene, which has significantly lower hydration activity than α-olefin, is extremely low. Further, according to additional tests conducted by the present inventors, the heteropolyacid is reduced during the reaction, and a metal oxide precipitates, resulting in the reaction system becoming a suspension. Such a suspension system not only causes troubles such as clogging of the equipment, but also has a significant drop in catalyst activity, which poses many problems from an industrial perspective. In view of these circumstances, the present inventors have conducted extensive research on catalysts used in the production of cyclic alcohols by hydrating cyclic olefins, and have found that a catalyst system consisting of a heteropolyacid and an aromatic sulfonic acid has a high It was discovered that a cyclic alcohol can be produced with a high conversion rate and high selectivity, and there is almost no decrease in catalyst activity due to long-term use, and based on this knowledge, the present invention has been completed. That is, the present invention is characterized in that a mixed catalyst comprising a heteropolyacid and an aromatic sulfonic acid is used in producing a cyclic alcohol by catalytically hydrating a cyclic olefin or a hydrocarbon mixture containing the cyclic olefin. The present invention provides a method for producing cyclic alcohols. The cyclic olefin used as a raw material in the method of the present invention is not particularly limited, but has the following general formula (1) C _o H _2o-2-n R _n ...(1) (R in the formula is a hydrogen atom, An alkyl group, phenyl group or cyclohexyl group having 1 to 4 carbon atoms, and n
is 5 to 12, m is an integer of 1 to 4) Compounds having the structure shown below are particularly suitable. Such cyclic olefins include, for example, cyclopentene, cyclohexene, cyclooctene, cyclononene, cyclodecene, cycloundecene, cyclododecene, methylcyclohexene,
Examples include dimethylcyclohexene, trimethylcyclohexene, tetramethylcyclohexene, and phenylcyclohexene. In the method of the present invention, these cyclic olefins may be used alone or as a mixture, or may be used as a mixture with other hydrocarbons. As the hydrocarbon mixture containing a cyclic olefin, a mixture containing at least one selected from aromatic hydrocarbons and cyclic paraffins is preferably used. This aromatic hydrocarbon is
Examples include benzene, toluene, xylene, diphenyl and the like, and examples of the cyclic paraffin include cyclohexane and cyclooctane. Incidentally, cyclohexene, which is a cyclic olefin that can be used as a raw material in the present invention, is usually produced by a dehydrohalogenation reaction of halogenated cyclohexane or a dehydrogenation reaction of cyclohexane. However, in the former method, it is difficult to sufficiently suppress by-products such as benzene and cyclohexane caused by the disproportionation reaction, and in the latter method, the conversion rate and cyclohexene selectivity are 100%.
Therefore, cyclohexene is often obtained as a mixture with cyclohexane and benzene. Furthermore, in the production of methylcyclohexene by partial hydrogenation of toluene, it is obtained as a mixture of toluene and methylcyclohexane, and furthermore, in the production of cyclooctene by partial hydrogenation of cyclooctadiene, it is obtained as a mixture with cyclooctane. This is often the case. Therefore, the method of the present invention can be said to be effective for cyclic olefins containing these aromatic hydrocarbons and cyclic paraffins. The heteropolyacid used as a component of the catalyst in the method of the present invention contains at least one metal atom selected from molybdenum, tungsten, and vanadium, and further contains other elements as condensed coordination elements. Good too. The central elements of this heteropolyacid are, for example, P, As, Si, Ge,
Ti, Ce, Th, Mn, Ni, Te, I, Co, Cr, Fe,
It is one selected from the group of Ga, B, V, Pt, Be, and Zn, and the atomic ratio of the condensed coordination element to the central element in the heteropolyacid is 2.5 to 12. Furthermore, as the heteropolyacid, not only monomers but also polymers such as dimers and trimers can be used. Specific examples of these heteropolyacids include phosphomolybdic acid, phosphotungstic acid, phosphomolybdotungstic acid, phosphomolybdovanacic acid, phosphomolybdotungstovanadate, phosphotungstovanadic acid, phosphomolybdoniobic acid, phosphorus Manganese tungstic acid, silicon molybdic acid, silicotungstic acid, silicon molybdo tungstic acid, silicon molybdo tungstovanadate, boromolybdic acid, borotungstic acid, boromolybdotungstic acid, boromolybdovanadate, boromolybdotungstovanadine Examples include cobalt molybdic acid, cobalt tungstic acid, and the like.
Among these, phosphomolybdic acid, phosphotungstic acid, silicotungstic acid, borotungstic acid, etc. are preferred. Examples of the aromatic sulfonic acid used as a component of other catalysts include aromatic monosulfonic acids and polysulfonic acids such as p-toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, and anthracenesulfonic acid. can. The mixing ratio of heteropolyacid and aromatic sulfonic acid used as a catalyst in the method of the present invention varies depending on the type of heteropolyacid and aromatic sulfonic acid, but the content of aromatic sulfonic acid based on the total amount of catalyst is usually 5 to 5. 95% by weight, preferably 10~
It is in the range of 90% by weight, more preferably 10-60% by weight. There is no particular restriction on the catalyst concentration in the method of the present invention, but the higher the catalyst concentration in the aqueous solution, the faster the reaction proceeds, so it is preferable, and the concentration is usually within the range of the saturated solubility of the heteropolyacid and aromatic sulfonic acid at the operating temperature. is used. When the reaction is carried out batchwise, the catalyst may be present in an amount higher than the saturation solubility, but when the reaction is carried out continuously, transportation problems arise, which is not preferable. Further, if the catalyst concentration is too low, the reaction rate is too slow to be practical, and the reaction is preferably carried out at a catalyst concentration of 10% by weight or more up to saturation solubility. In the mixed catalyst of the present invention of a heteropolyacid and an aromatic sulfonic acid, the solubility of the heteropolyacid is increased by mixing the aromatic sulfonic acid, and it is possible to prepare a so-called highly concentrated catalyst aqueous solution. Since precipitation during and after the reaction is significantly reduced, this highly concentrated catalyst can be used stably over a long period of time. In the method of the present invention, the greater the amount of catalyst used, the greater the conversion rate of cyclic olefin. At this time, if an aromatic hydrocarbon or a cyclic paraffin is contained in the cyclic olefin as a raw material, the conversion rate of the cyclic olefin will decrease, but the decrease in the conversion rate can be compensated for by further increasing the amount of catalyst. The preferred amount of the catalyst to be used in the present invention varies greatly depending on whether the reaction format is batchwise or continuous, and cannot be determined unconditionally. 0.1 to 200 to parts by weight
Parts by weight of catalyst are preferably used. The amount of catalyst
If it is less than 0.1 part by weight, the reaction rate will be low, and if it exceeds 200 parts by weight, it will be economically disadvantageous. The reaction temperature in the method of the present invention is preferably lower in terms of chemical equilibrium, and in this respect, the method of the present invention is industrially advantageous because it can be carried out at a relatively low temperature due to the high catalytic activity. The reaction temperature is usually 50~
It is carried out at 180°C, preferably in the range of 70 to 150°C.
If the reaction temperature is less than 50°C, the reaction rate will be extremely slow, which is not practical. Further, the reaction pressure is preferably higher than the pressure required to maintain the liquid phase under the reaction conditions, and at this time, the pressure can also be adjusted by introducing an inert gas such as nitrogen gas. Furthermore, in the method of the present invention, phosphoric acid may be present in an amount of 1% by weight or less based on the catalyst, if desired. By coexisting phosphoric acid, the stability of the heteropolyacid is further improved and the catalyst life is further extended. The embodiment of the present invention may be a batch type, a continuous type, or a semi-batch type, but a continuous type is preferable for efficient implementation. The method of the present invention uses a cyclic olefin or a hydrocarbon mixture containing a cyclic olefin as a raw material, and performs a hydration reaction using a mixture of a heteropolyacid and an aromatic sulfonic acid as a catalyst, thereby achieving a high conversion rate and high yield. Produces cyclic alcohols with selectivity,
Furthermore, the catalyst of the present invention is an industrially excellent method, with almost no decrease in activity observed after long-term use. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Phosphormolybdic acid (p:Mo = 1:12 atomic ratio) and p-toluenesulfonic acid were put in various ratios to a total of 12g in a 50ml glass ampoule tube, and water was added to the catalyst. The total amount of water including crystal water
Add so that it weighs 12g. Next, cyclohexene 1
ml, seal the ampoule tube, set it in an oil shaker adjusted to 100℃, and shake for 1 hour. Next, the ampoule was opened, the reaction solution was taken out, water was added thereto, solvent extraction was repeated, and unreacted cyclohexene, the reaction product cyclohexanol, and byproducts were quantified by gas chromatography. . The results are shown in Table 1. It is clear from Table 1 that phosphomolybdic acid and p
-Toluenesulfonic acid It can be seen that the conversion rate of cyclohexene is higher when a mixed catalyst is used than when each is used alone.

[Table] * Comparative Example Example 2 In a 500 ml autoclave, add 100 ml of water, 150 g of phosphotungstic acid, 20 g of benzenesulfonic acid, and 40% by weight each of benzene and cyclohexane, 10
25 ml of cyclohexene containing % by weight was added, and the temperature was raised while stirring, kept at 90°C for 1 hour, and then cooled with water. After cooling, the reaction solution was taken out, 200 ml of water was added, and solvent extraction was repeated. Unreacted cyclohexene, cyclohexanol, by-products, etc. in the solvent were determined by gas chromatography.
As a result, the conversion rate of cyclohexene was 80%, and the selectivity to cyclohexanol was 99.8%. Examples 3 to 14 Reactions were carried out in the same manner as in Example 1 by changing reaction conditions such as catalyst, temperature, and time. The results are shown in Table 2.

[Table] Example 15 1 Using an autoclave (made of SUS32),
While stirring, feed cyclohexene at 40 g/Hr. At the same time, add 0.5% by weight of phosphoric acid to the catalyst.
An aqueous solution with a catalyst concentration of 60% by weight containing a catalyst in which phosphomolybdic acid and p-toluenesulfonic acid were mixed at a ratio of 9:1 by weight was
Supply in g/Hr. The reaction was carried out continuously under the conditions of 130°C, 3 atm, and an average reaction time of 1 hour, and the effluent from the autoclave was led to a vacuum distillation column to perform vacuum distillation. Cyclohexene 11.6g/from the top of the tower
Hr, cyclohexanol 34.6g/Hr was obtained,
The conversion rate of cyclohexene was 71%. On the other hand, water was added to the catalyst aqueous solution obtained from the bottom of the column to adjust the specific gravity to be the same as that of the supplied catalyst aqueous solution (1.71 g/cc), and then the solution was recycled and used. As a result of continuous operation for 5 days, the above results were obtained almost stably. In addition, 60% by weight as the same equipment and catalyst aqueous solution
As a result of continuous operation under the same conditions using an aqueous solution of phosphomolybdic acid, the pump became clogged and operation became impossible approximately 13 hours after the start (3rd cycle of the catalyst). There was a blackish green deposit attached to the check valve. In addition, the top liquid at this time was 26.3 g of cyclohexene/
Hr, cyclohexanol was 14.6 g/Hr, and the conversion rate of cyclohexene was 34.3%. Example 16 In a 50ml glass ampoule tube, 5g of phosphomolybdic acid, 5g of p-toluenesulfonic acid, and 10g of water
Put in. After adding 1 ml of cyclooctene, the ampoule tube was sealed and kept at 120°C for 3 hours with shaking. Next, analysis was performed in the same manner as in Example 1, and the conversion rate of cyclooctene was 38%, and no by-products other than cyclooctanol were observed. Examples 17 to 22 Reactions were carried out in a glass ampoule tube in the same manner as in Example 16, changing conditions such as the type of cyclic olefin, catalyst, temperature, time, etc., and corresponding cyclic alcohols were obtained. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. A catalyst system comprising a heteropolyacid and an aromatic sulfonic acid is used in producing a cyclic alcohol by catalytically hydrating a cyclic olefin or a hydrocarbon mixture containing the cyclic olefin. A method for producing a cyclic alcohol. 2 Cyclic olefin has the general formula C _o H _2o-2-n R _n (R in the formula is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a cyclohexyl group, and n
5 to 12, and m is an integer of 1 to 4.) The method according to claim 1, wherein 3. The method according to claim 1, wherein the hydrocarbon mixture containing a cyclic olefin is a mixture containing at least one selected from aromatic hydrocarbons and cyclic paraffins.