JPH05155811A - Production of carboxylic acid cyclohexyl ester - Google Patents

Abstract

PURPOSE:To extremely effectively produce a carboxylic acid cyclohexyl ester as a precursor of cyclohexanol at low temperature in a short time and in high yield. CONSTITUTION:A carboxylic acid is reacted with cyclohexene in the presence of a hetero-polyacid consisting mainly of an oxide of tungsten represented by phosphotungstic acid or silicotungstic acid as a catalyst to produce a carboxylic acid cyclohexyl ester. In the reaction, an amount of water of crystallization which the hetero-polyacid consisting essentially of the oxide of tungsten possesses is adjusted to <=3.0 molecules per the hetero-polyacid to extremely improve the catalytic action.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a carboxylic acid cyclohexyl ester. More specifically, it relates to a method for producing a carboxylic acid cyclohexyl ester by reacting a carboxylic acid with cyclohexene in the presence of a heteropoly acid mainly composed of an oxide of tungsten.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a carboxylic acid cyclohexyl ester, it has long been known that it is produced by an esterification reaction between cyclohexanol and a carboxylic acid and a reaction between cyclohexanol and a carboxylic acid anhydride. .. However, these methods both use cyclohexanol as a raw material, and the use of cyclohexanol has various drawbacks such as a problem in the production method. In addition, since the esterification reaction is an equilibrium reaction, it is difficult to produce the ester in a high reaction yield, and it is necessary to take measures to remove water as a by-product. Further, in the method using a carboxylic acid anhydride, the yield of the ester is high, but the carboxylic acid anhydride used is expensive, and in addition, one molecule of carboxylic acid is released,
Converting this carboxylic acid into an anhydride has various drawbacks such as being extremely difficult. Here, as a method for solving these problems, an addition reaction of acetic acid and cyclohexene in the presence of a catalyst has recently been proposed as a method for producing a carboxylic acid cyclohexyl ester by an addition reaction of cyclohexene and a carboxylic acid. For example, in JP-A-1-254634, cyclohexyl acetate is produced by reacting cyclohexene with acetic acid using a strongly acidic cation exchange resin as a catalyst. However, in this patent, it is necessary to carry out the reaction at 130 ° C. for 5 hours in order to obtain cyclohexyl acetate in a high yield, and when using a cation exchange resin, the reaction temperature is extremely high and the reaction time is long. Is long. In addition, as a characteristic of these strongly acidic cation exchange resins, the heat-resistant temperature is generally around 100 ° C., and even a highly heat-resistant resin does not substantially exceed 160 ° C. Further, since these exchange resins also have drawbacks such as low mechanical strength and easy breakage, they have an extremely high risk of stability as a catalyst, and at the same time have low catalytic activity. In JP-A-1-313447, the addition reaction between acetic acid and cyclohexene is carried out in the presence of water using ZSM-5, which is a high silica zeolite, as a catalyst. In this method, the reaction temperature is 120 ° C. and the reaction time is 4 hours. Yield 1
Cyclohexyl acetate is finally obtained with a yield of 65% together with 2.5% of cyclohexanol, and the catalytic activity is low.
In addition, in these patents, the carboxylic acid is limited to acetic acid only, and there is still no knowledge about the addition reaction with other aliphatic carboxylic acids and aromatic carboxylic acids. Carboxylic acids often have extremely different reactivities, effects on catalysts, cyclohexene and the like due to differences in chemical and physical properties such as acidity, solubility and structure.

[0003]

The object of the present invention is to produce a carboxylic acid cyclohexyl ester in a short time with a high selectivity and a high conversion rate by the addition reaction of cyclohexene with a carboxylic acid, and to carry out the reaction even in a high temperature region. The purpose is to provide a catalyst that can be stably carried out.

[0004]

Means for Solving the Problems The present inventors have investigated an efficient method for producing cyclohexyl carboxylate, and paying attention to the fact that the addition reaction between cyclohexene and carboxylic acid is an excellent production method. As a result of diligent studies to solve problems such as low catalytic activity, durability of the catalyst including mechanical strength and heat resistance, a heteropoly acid mainly composed of tungsten oxide was used as a catalyst in the reaction system. The present invention has been found to proceed extremely efficiently when it is present in the solution, and has completed the method of the present invention. That is, a method for producing cyclohexyl carboxylate, which comprises reacting an aliphatic carboxylic acid or an aromatic carboxylic acid with cyclohexene in the presence of a heteropoly acid mainly composed of an oxide of tungsten, having a general formula: (M ₁ ) a (M ₂ ) b (W) c (O) d (H) e (however, M ₁ , M ₂
Represents a metal atom, W represents a tungsten atom, O represents an oxygen atom, and H represents a hydrogen atom. Further, a is an integer of 1 or 2, b is an integer of 0, 1 or 2, and c is 2.
It is a positive integer of 0 or less, d is a positive integer of 100 or less, and e is a positive integer of 10 or less. ) Is used as a catalyst. In these general formulas, M ₁ is an element symbol, and P, Si, Co, Mn, Ni, As, T
An element represented by any one of i, Fe, V and B, and an element represented by M ₂ as an element symbol V is preferable, and it is particularly preferable to use tungstosilicic acid and / or molybdosilicic acid.

Further, these heteropolyacids may be those containing amorphous water and / or water of crystallization, but the amount of water of crystallization of these heteropolyacids is 3 on average per molecule of the heteropolyacid. A heteropoly acid adjusted to 0.0 molecule or less is a more preferable catalyst. Furthermore, by heat-treating these heteropolyacids in the temperature range of 150 ° C. to 500 ° C. or by heat-treating them under the flow of an inert gas, the amount of water of crystallization contained on average per molecule of the heteropolyacid is A method of producing a heteropoly acid adjusted to 3.0 molecules or less as a catalyst is preferable as a dehydration adjusting method. In addition, in the method of the present invention, when a catalyst adjusted to an average of 3.0 molecules or less per one molecule of the heteropolyacid is subjected to the reaction, other than the water of crystallization contained in the heteropolyacid to be subjected to the reaction, It is more preferable to adjust the amount of water to be present in the reaction system to 30 molecules or less per one molecule of the heteropolyacid used.

The method of the present invention will be described in detail below. The carboxylic acids and cyclohexene used in the method of the present invention do not need to be particularly purified, and carboxylic acids and cyclohexene having a general reagent purity can be used as they are. It is more preferable to remove water. Here, the carboxylic acids used in the method of the present invention are aliphatic carboxylic acids and aromatic carboxylic acids, and specific examples of the aliphatic carboxylic acids include formic acid, propionic acid, butyric acid and the like having 1 to 15 carbon atoms. C3-C15 aliphatic unsaturated carboxylic acids such as saturated carboxylic acids, acrylic acid, and methacrylic acid, and halogen atoms, cyano groups, nitro groups,
Hydroxyl groups, amino groups, aliphatic saturated carboxylic acids having 1 to 15 carbon atoms partially substituted with a sulfone group, and aliphatic unsaturated carboxylic acids having 3 to 15 carbon atoms, and in addition to monocarboxylic acid, di-, Also included are polycarboxylic acids such as tri-carboxylic acids. The aromatic carboxylic acids are aromatic mono- and polycarboxylic acids, specifically, benzoic acid, naphthalenecarboxylic acids, phthalic acids, and the like, and
It is an aromatic mono- or polycarboxylic acid having 7 to 25 carbon atoms, which is substituted with a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amino group, a sulfone group, an alkyl group, an allyl group or the like.

The catalyst used in the process of the present invention is a heteropolyacid, and has the general formula (M ₁ ) a (M ₂ ) b (W) c (O) d (H) e (provided that M ₁
Is an element represented by the element symbols P, Si, Co, Mn, Ni, As, Ti, Fe, V, B, etc., M ₂ is an element represented by the element symbol V, etc.,
W is a tungsten atom atom, O is an oxygen atom, H is a hydrogen atom, a is 1 or 2, b is 0, 1 or 2, and c is 20.
The following positive integers, d is a positive integer of 100 or less, and e is 10
It is a heteropoly acid represented by the following positive integer). Specifically, dodecatungstosilicic acid (SiW ₁₂ O ₄₀ H ₄ ), dodecatungstophosphoric acid (PW ₁₂ O ₄₀ H ₃ ), and a structure in which one or more of these tungsten atoms are replaced with vanadium atoms The heteropoly acid and the like that it has are listed as the most easily available heteropoly acid. However, the method of the present invention is not limited to these heteropolyacids.
Heteropolyacids usually contain water of crystallization. Here, the water of crystallization of the heteropolyacid is a general term for water contained in the heteropolyacid at the time of commercial production or preparation, and specifically, when the heteropolyacid is prepared in a water-containing solvent, these are nonsolvents, etc. Water attached or incorporated into the heteropolyacid crystal when precipitated by, or water incorporated with the heteropolyacid by adsorption, deliquescence, or the like. For example, in the commercially available dodecatungstosilicic acid, the general formula H ₄ Si
W ₁₂ O ₄₀ · nH indicated by ₂ O, also, although commercial dodecatungstophosphoric acid represented by the general formula _{H 3 PW 12 O 40 · nH} 2 O, that of nH ₂ O shown in these above formulas And the water molecules incorporated in or adsorbed in or contained in the crystal structure of the heteropolyacid. Therefore, in the method of the present invention, it is meant that the heteropolyacid represented by the above general formula has n molecules of water of crystallization. Since n is an average value, it is not necessarily an integer, but a real number. The value of n in the above formula is usually about 25 to 30 for commercially available heteropolyacids. Further, the value may be more than this value due to the adsorption of water or the like. It is possible to easily set the value of n to 0 in the water of crystallization that these have by performing dehydration treatment such as heating. In addition, the dehydrated heteropolyacid can easily increase the value of n again by a method of adsorbing water.

A method for controlling the water of crystallization contained in the heteropolyacid as a catalyst used in the present invention to 3.0 molecules or less per one molecule of the heteropolyacid will be described. Usually, the readily available heteropoly acid is heteropoly acid 1 as described above.
It contains several tens of molecules of crystal water per molecule. There is no particular limitation in the method of the present invention for the method of setting the water of crystallization of these heteropolyacids to 3.0 molecules or less on average per molecule of the heteropolyacid, but a method that can be easily carried out includes a heat dehydration operation. As the heating and dehydrating operation, for example, heating in an ordinary electric furnace (muffle furnace) is recommended. Of course, the method of the present invention is not limited to this apparatus and method. The heating temperature is not particularly limited, and any temperature may be used as long as the water of crystallization is 3.0 molecules or less on average per one molecule of the heteropolyacid, but it is more effective. 80 ℃ to implement
It is preferable to carry out at a temperature of 500 ° C. or higher and more preferably 200 ° C. or higher and 450 ° C. or lower. At low temperature, it is difficult to dehydrate, and at 550 ° C. or higher, it may become a heteropolyanhydride. At this time,
The required heating time is not particularly limited, and if the amount of water of crystallization is in the above range, there is no problem, but it is in the range of 10 minutes to 24 hours. For example, if a normal electric filter is used and dehydration operation is performed at around 300 ° C, 3
The amount of water of crystallization is sufficiently reached within about time.

A catalyst for heteropoly acid whose average molecular weight is 3.0 molecules or less per one molecule of the heteropolyacid is obtained by carrying out a heating dehydration operation under a flow condition of a gas inert to the heteropolyacid at a heating dehydration temperature. When used as, the catalytic activity is further improved. This operation makes it possible to provide a very effective catalyst. Here, the gas that is circulated during the heating and dehydration operation may be any gas that is inert to the heteropolyacid at the heating temperature. Further, even if it is a liquid or a solid at room temperature, it can be used if it is a gas at the heating temperature and is inert to the heteropolyacid. Specific examples thereof include air, argon, nitrogen, helium, hydrogen, aliphatic hydrocarbons and aromatic hydrocarbons, but the method of the present invention is not limited to these gases. Further, the flow rate of the inert gas is not particularly limited, but it is preferably in the range of 0.2 to 20 vol / Hr * vol as the space velocity in the apparatus in terms of gas volume at the heating temperature.

The reaction of carboxylic acid and cyclohexene to carboxylic acid cyclohexyl ester in the method of the present invention proceeds as an addition reaction. At that time, the reaction is carried out as a liquid phase homogeneous system, a solid phase-liquid phase or a solid phase-gas phase heterogeneous system. The method of the present invention can be carried out under any conditions of normal pressure, reduced pressure and increased pressure. When it is carried out at a high temperature, a liquid phase reaction can be carried out by applying pressure.
The reaction system is not particularly limited, but a continuous system, a batch system or a semi-batch system can be used.

In carrying out the method of the present invention, it is possible to add a solvent or an additive which is inert to the catalyst and the reaction reagents (raw materials and products). Specifically, n-
Butane, n-pentane, n-hexane, n-heptane,
Aliphatic saturated hydrocarbons such as n-octane, n-nonane, and n-decane, aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, anisole, cumene, and nitrobenzene, cyclopentane, alkyl-substituted cyclopentanes , Alkoxy-substituted cyclopentanes,
Nitro-substituted cyclopentanes, cyclohexane, alkyl-substituted cyclohexanes, alkoxy-substituted cyclohexanes, nito-substituted cyclohexanes, cycloheptane, alkyl-substituted cycloheptanes, alkoxy-substituted cycloheptanes, nitro-substituted cycloheptanes, cyclooctane, alkyl-substituted cyclohexanes It is also possible to use alicyclic saturated hydrocarbons such as octanes, alkoxy-substituted cyclooctanes and nitro-substituted cyclooctanes, and nitrogen, argon, air, helium and the like as a solvent or a diluent.

The quantitative relationship between the carboxylic acid and cyclohexene charged when carrying out the reaction in the method of the present invention is not particularly limited. The amount ratio of carboxylic acid / cyclohexene is in the range of 0.1 to 100 (molar ratio). For example, in order to achieve a high conversion of carboxylic acid, it is desirable to carry out the molar ratio of cyclohexene to carboxylic acid at 1 or more, and in order to achieve a high conversion of cyclohexene, the conversion of carboxylic acid to cyclohexene is desired. It is desirable that the molar ratio be 1 or more.

In carrying out the method of the present invention, the amount of the catalyst to be added is not particularly limited, but, for example, when the reaction is carried out in a batch system, it is 0.1% by weight based on the charged cyclohexene. To 100% by weight, preferably 1
To 50% by weight is recommended. If the amount is less than this, the reaction proceeds slowly, and if the amount is more than this, the reaction proceeds sufficiently, but it is hard to say that it is preferable from the economical point of view. However, it is needless to say that the method of the present invention can be carried out outside the range.

In carrying out the method of the present invention, the method of charging the catalyst and the reaction reagent is not particularly limited, and the catalyst, carboxylic acid, cyclohexene and the like may be charged at the same time, and the catalyst may be dissolved in another solvent or the like. Alternatively, it may be suspended and prepared. Furthermore, a method of previously mixing the carboxylic acid and the catalyst before the reaction and then adding cyclohexene, and a method of previously mixing the cyclohexene and the catalyst and then adding the carboxylic acid can also be carried out. Here, when carrying out the method of the present invention,
When the heteropolyacid catalyst used has an average of 3.0 molecules or less of crystal water per molecule of the heteropolyacid, the amount of water in the reaction system particularly affects the reaction results.
In particular, in order to develop higher catalytic activity than a catalyst having several tens of molecules of crystallization water per molecule of the heteropolyacid, which is usually commercially available, the amount of water other than the crystallization water of the heteropolyacid is one molecule of the heteropolyacid used. It is necessary to control the water content so that the number of molecules per molecule is 30 or less. When the amount of water is more than this, the effect of dehydration of the water of crystallization of the heteropolyacid does not appear. At this time, the amount of water contained in the above-mentioned commercially available carboxylic acid and cyclohexene is at most 100.
When the commercially available carboxylic acid and cyclohexene are used in the method of the present invention, the concentration is about ppm and the amount of the catalyst added to the reaction system is in the order of% with respect to the reaction system.
The amount of water (excluding the water of crystallization of the catalyst) in the reaction system does not exceed the above value.

The reaction temperature in the method of the present invention is not particularly limited, and it can be carried out in a wide temperature range, but it is preferably in the range of 0 ° C to 400 ° C, and more preferably in the range of 0 ° C to 400 ° C. It is recommended to carry out above 30 ° C and below 200 ° C. If it is carried out at an excessively low temperature, the reaction rate will be lowered, and if it is carried out at an excessively high temperature, the thermal stability of the reaction reagent such as cyclohexene will be lowered, which is not economical. The reaction time depends on the amount of catalyst or the reaction temperature, but if the amount of catalyst is large and the temperature is high, it is extremely short (about 0.1 seconds or less), and if the amount of catalyst is small and the temperature is low, it is long (24 seconds). It is about time). After completion of the reaction, the target product can be obtained by a separation operation such as a normal distillation operation.

A specific mode for carrying out the method of the present invention will be described. The method for carrying out the method of the present invention is not particularly limited, but the following methods are mentioned as methods that can be easily carried out. Of course, the method of the present invention is not limited to these methods. (1) A glass flask equipped with a stirrer is charged with a predetermined amount of catalyst, acetic acid and cyclohexene together with a diluent such as a solvent if necessary, and a reflux condenser is attached if necessary, followed by heating and stirring reaction. How to do. (2) A method in which a predetermined amount of catalyst, acetic acid and cyclohexene are put into an autoclave together with a medium such as nitrogen or argon if necessary, and then a reaction with heating and stirring is performed. (3) A method in which a predetermined amount of catalyst, cyclohexene, and acetic acid are continuously introduced together with a diluent such as a solvent, if necessary, into a reactor previously kept at a predetermined temperature and a predetermined pressure to carry out the reaction.

[0017]

EXAMPLES The method of the present invention will be described more specifically below with reference to examples. (1) Quantification of reaction product After the reaction product is reacted at a predetermined temperature for a predetermined time,
After cooling to room temperature, the reaction solution was quantified by gas chromatography. (2) Quantification of water of crystallization contained in the catalyst The amount of structural water contained in the heteropolyacid mainly composed of oxides of tungsten is such that each heteropolyacid is heated and dehydrated at 500 ° C and its weight becomes constant. When the amount of water of crystallization was 0, the amount of water of crystallization was 0. (3) Method for decrystallizing water of catalyst a. 350 in a normal muffle furnace (8 liters internal volume)
The amount of water of crystallization was adjusted by heating and dehydrating at ℃ for a predetermined time. b. While heating the air in the muffle furnace at 5 N liters per hour, it is heated and dehydrated at 350 ° C. for 3 hours to reduce the amount of water of crystallization.
And c. In the above method b, except that the circulating gas was changed to argon, heating and dehydration were performed by the same operation, and the amount of water of crystallization was reduced to 0.
And

Example 1 70 ml equipped with a magnetic stirrer and a reflux condenser
In a three-necked flask containing dodecatungstophosphoric acid (H ₄ PW
₁₂ O ₄₀・ 29H ₂ O) 2.0 g, commercial acrylic acid (manufactured by Kokusan Kagaku Co., special grade) 25.0 g, and commercially available 98% cyclohexene (Tokyo Kasei Co., special grade) 4.5 g are added at 70 ° C. in advance.
Attach this flask to the oil bath that has been heated to
After heating and stirring reaction at 70 ° C. for 1.5 hours, stirring was stopped, the flask was taken out of the oil bath, and the reaction liquid was quantified after cooling to room temperature. The result was a cyclohexyl acrylate yield of 13.5%. Comparative Example 1 The reaction was carried out under the same reaction conditions as in Example 1 except that dodecatungstophosphoric acid was not added. As a result, the formation of cyclohexyl acrylate was not observed, and only cyclohexene and acrylic acid as the raw materials were recovered.

Example 2 The reaction between cyclohexene and acrylic acid was carried out under the same conditions as in Example 1 except that the reaction time was changed to 3 hours. The result is 40.
It was produced in a yield of 2%.

[0020] Example 3 catalyst a commercial dodecatungstophosphoric silicate _{(H 4 SiW 12 O 40 ·} 25
The reaction between acrylic acid and cyclohexene was carried out under the same conditions as in Example 1 except that the amount of catalyst used was changed to H ₂ O). As a result, cyclohexyl acrylate was obtained with a yield of 8.2%.

Examples 4 to 5 All tests were carried out except that the reaction time was 1 hour, the catalyst was adjusted to 0 for water of crystallization by dehydration method a, and 2.0 g each of dodecatungstophosphoric acid and dodecatungstosilic acid were used. Acrylic acid and cyclohexene were reacted under the same conditions as in Example 1. As the results are shown in Table 1, cyclohexyl acrylate was obtained in an extremely high yield.

[0022]

[Table 1] ─────────────────────────────────── Catalyst (amorphous water) Siclohexyl acrylate yield (%) ─────────────────────────────────── Example 4 Dodecatungstophosphoric acid 86.4 Example 5 Dodecatungstosilicic acid 79.0 ────────────────────────────────────

Example 6 16.1 g of commercially available formic acid (Kanto Kagaku, special grade)
The reaction between formic acid and cyclohexene was carried out under the same conditions as in Example 1 except that the reaction temperature was 40 ° C. and the reaction time was 1 hour. As a result, the yield of cyclohexyl formate is 6.
Produced at 2%. Comparative Example 2 The catalyst dodecatungstophosphoric acid (H ₃ PW ₁₂ O ₄₀ / 28H ₂
The reaction between formic acid and cyclohexene was carried out under the same conditions as in Example 6 except that O) was not added. The result was that cyclohexyl formate was only obtained with a yield of 1.0%. From this, the catalytic effect of dodecatungstophosphoric acid is clear.

Examples 7 to 8 Dodecatungstophosphoric acid (by dehydration method a) (H ₃ PW ₁₂ O ₄ 0 .0 H ₂ O) obtained by decrystallizing water of the catalyst, respectively, and dodecatungstosilic acid (H ₄ SiW ₁₂ O ₄₀₎ · 0H ₂ O) and then addition was made a reaction of formic acid and cyclohexene under the same conditions as in example 6. As shown in Table 2, the formation of cyclohexyl formate was observed in high yield even under extremely mild conditions of 40 ° C. for 1 hour.

[0025]

[Table 2] ─────────────────────────────────── Catalyst (amorphous water) Cyclohexyl formate yield ( %) ─────────────────────────────────── Example 7 Dodecatungstophosphoric acid 15.7 Example 8 Dodecatungstosilicic acid 84.1 ────────────────────────────────────

Example 9 The reaction between formic acid and cyclohexene was carried out under the same conditions as in Example 8 except that the reaction temperature was 70 ° C. As a result, cyclohexyl formate was obtained in a yield of 98.1%.

Example 10 Carboxylic acid was changed to propionic acid (Kanto Kagaku, special grade) 25.9
The reaction between propionic acid and cyclohexene was carried out under the same conditions as in Example 9 except that the reaction time was g and the reaction time was 1.5 hours. As a result, cyclohexyl propionate was produced in a yield of 81.5%.

Examples 11-16 All Example 10 except that the catalysts listed in Table 4 were used instead of the catalysts.
The results of the reaction of propionic acid with cyclohexene under the same conditions as in Table 4 showed that cyclohexyl propionate was obtained in good yields as shown in Table 4. The water of crystallization contained in the catalyst was adjusted by heating and dehydrating according to the above method a.

[0029]

[Table 3] ─────────────────────────────────── Catalyst Yield of cyclohexyl propionate (%) ── ───────────────────────────────── Example 11 H ₃ PW ₁₂ O ₄₀・ 0H ₂ O 94.6 Implementation Example 12 H ₃ PW ₁₂ O ₄₀ · 1.6H ₂ O 94.1 Example 13 H ₃ PW ₁₂ O ₄₀ · 2.7H ₂ O 82.4 Example 14 H ₃ PW ₁₂ O ₄₀ · 28H ₂ O 3.1 Implementation Example 15 H ₄ SiW ₁₂ O ₄₀ · 1.8H ₂ O 81.3 Example 16 H ₄ SiW ₁₂ O ₄₀ · 2.9H ₂ O 77.6 ────────────────── ──────────────────

Examples 17 to 19 The results of carrying out the reaction of propionic acid and cyclohexene under the same conditions as in Example 10 except that the reaction times were 0.5, 1.0 and 3.0 hours are shown in Table 5. As shown in the above, the formation of cyclohexyl propionate was observed in a high yield even in an extremely short time.

[0031]

[Table 4] ──────────────────────────────────── Reaction time (HR) Cyclohexyl propionate yield (%) ─────────────────────────────────── Example 17 0.5 62.7 Example 18 1.0 75.1 Example 19 3.0 86.5 ────────────────────────────────────

Example 20 The reaction of propionic acid and cyclohexene was carried out under the same conditions as in Example 18 except that the catalyst was heated and dehydrated by the method b to give non-crystallized water, which was replaced with dodecatungstosilicic acid.
As a result, cyclohexyl propionate yield 80.3%
Generated by.

Example 21 The reaction of propionic acid and cyclohexene was carried out under the same conditions as in Example 18, except that the catalyst was heated and dehydrated by the method c to be non-crystallized water, which was replaced with dodecatungstosilicic acid. As a result, the yield of cyclohexyl propionate was 81.
Produced at 1%.

Examples 22 to 25 In Example 11, water was further added per catalyst molecule: 2,
The reaction of propionic acid and cyclohexene was carried out under the same conditions as in Example 11 except that the addition was carried out so as to give 5, 10, and 30 molecules. As shown in Table 5, the formation of cyclohexyl propionate was confirmed.

[0035]

[Table 5] ─────────────────────────────────── Added water Cyclohexyl propionate (per 1 molecule of catalyst) Number of moles) Yield (%) ─────────────────────────────────── Example 22 2 94.7 Example 23 5 92.1 Example 24 10 86.9 Example 25 30 7.3 ───────────────────────────── ──────

Comparative Example 3 The reaction of propionic acid with cyclohexene was carried out under the same conditions as in Example 11 except that 50 molecules of water were added per molecule of catalyst. As a result, formation of cyclohexyl propionate was not observed.

Example 26 Dedecatungstophosphoric acid 2.0 g and propionic acid 7 which had been decrystallized in a 200 ml autoclave (dehydrated by method a)
After charging 8 g and 13.5 g of cyclohexene, pressurize with nitrogen gas to 10 kg per square centimeter,
The mixture was heated and stirred at 120 ° C for 1 hour. When the reaction solution was cooled to room temperature and analyzed, cyclohexyl propionate was produced in a yield of 91.2%.

Example 27 The reaction of propionic acid and cyclohexene was carried out under the same reaction conditions as in Example 26 except that the reaction temperature was 150 ° C. and the amount of the catalyst used was 1.0 g. As a result, cyclohexyl propionate was produced at a yield of 89.6%.

Example 28 The reaction between propionic acid and cyclohexene was carried out under the same conditions as in Example 27 except that the reaction temperature was 180 ° C. and the reaction time was 0.5 hours. As a result, cyclohexyl propionate was produced in a yield of 90.7%.

Example 29 Carboxylic acid was converted into dichloroacetic acid (Tokyo Kasei, special grade) 45.1
The reaction of dichloroacetic acid and cyclohexene was carried out under the same conditions as in Example 10 except that the amount was changed to g. As a result, cyclohexyl dichloroacetate was produced in a yield of 93.4%. Comparative Example 4 The reaction was carried out under the same conditions as in Example 24 except that no catalyst was added. As a result, the yield of cyclohexyl dichloroacetate was 4.3%, which was extremely low.

Examples 30 and 31 The reaction was carried out under the same conditions as in Example 29 except that the reaction temperatures were 50 ° C. and 40 ° C., respectively. As shown in Table 6, cyclohexyl dichloroacetate was found to be produced at an extremely high yield even at low temperatures.

[0042]

[Table 6] ─────────────────────────────────── Reaction temperature Dichloroacetate Cyclohexyl yield (%) ─ ────────────────────────────────── Example 30 50 ° C. 92.3 Example 31 40 ° C. 89.5 ───────────────────────────────────

Examples 32 to 34 The reaction between dichloroacetic acid and cyclohexene was carried out under the same conditions as in Example 25 except that the catalysts were replaced as shown in Table 7. As a result, as shown in Table 7, formation of cyclohexyl dichloroacetate was observed in high yield.

[0044]

[Table 7] ─────────────────────────────────── Catalyst Dichloroacetate Cyclohexyl yield (%) ── ───────────────────────────────── example _{32 H 4 SiW 12 O 40 ·} 24H 2 O 58.6 embodiments Example 33 H ₃ PW ₁₂ O ₄₀・ 28H ₂ O 76.0 Example 34 H ₃ PW ₁₂ O ₄₀・ 0H ₂ O 94.7 ─────────────────── ────────────────

[0045]

According to the method of the present invention, cyclohexyl carboxylate can be produced extremely efficiently by the addition reaction of carboxylic acid and cyclohexene in the presence of a heteropoly acid mainly containing tungsten oxide. Become. In addition, it overcomes the disadvantages of conventional catalysts such as low activity and low durability, and is a very important method for producing cyclohexyl carboxylate. Further, the heteropoly acid is subjected to dehydration treatment such as heating, etc., and the amount of water of crystallization usually contained in the heteropoly acid is adjusted in advance to 3.0 molecules or less on average per 1 molecule of the heteropoly acid. It was also found that by using it, extremely high reaction efficiency was expressed, and cyclohexyl carboxylate was obtained with high selectivity and high conversion in extremely mild conditions and in a short time of about 1 hour, and it was stable and effective even at high temperatures. It became possible to carry out the reaction.

Claims (10)

[Claims] 1. A method for producing a carboxylic acid cyclohexyl ester, which comprises reacting a carboxylic acid and cyclohexene in the presence of a heteropoly acid mainly containing tungsten oxide. 2. A method for producing a carboxylic acid cyclohexyl ester by an addition reaction of cyclohexene with a carboxylic acid, which comprises the general formula: (M ₁ ) a (M ₂ ) b (W) c (O) d (H) e (provided that M ₁ and M ₂ represent a metal element, W represents a tungsten atom atom, O represents an oxygen atom, H represents a hydrogen atom, a is an integer of 1 or 2, and b is 0, 1 or 2 is an integer, c is a positive integer of 20 or less, d is a positive integer of 100 or less, and e is a positive integer of 10 or less.) A heteropoly acid having the formula (1) is used as a catalyst.
The method described. 3. M ₁ is an element symbol of P, Si, Co, Mn, Ni, A
The method according to claim 2, wherein the element represented by any one of s, Ti, Fe, V and B, and M ₂ is an element represented by V in the element symbol. 4. A heteropoly acid is an amorphous water product of the acid and / or
The method according to claim 1, which further comprises water of crystallization. 5. The method according to claim 1, wherein the amount of water of crystallization contained in the heteropoly acid is adjusted to an average of 3.0 molecules or less per molecule of the heteropoly acid. 6. A heteropoly acid in which the amount of water of crystallization contained in the heteropoly acid is adjusted to an average of 3.0 molecules or less per molecule by subjecting the heteropoly acid to a heat treatment in the temperature range of 150 ° C. to 500 ° C. 6. The method of claim 5, wherein: 7. The method according to claim 6, wherein the heteropolyacid is heated and dehydrated under the flow of a gas inert to the heteropolyacid. 8. The method according to claim 5, wherein water other than the water of crystallization contained in the heteropolyacid in the reaction system is reacted with 30 molecules or less per molecule of the heteropolyacid. 9. The method according to claim 1, wherein the heteropolyacid is tungstophosphoric acid, tungstosilicic acid and a mixture thereof. 10. The method according to claim 1, wherein the carboxylic acid is an aliphatic carboxylic acid other than acetic acid or an aromatic carboxylic acid.