JPH04226940A - Production of cyclohexyl acetate - Google Patents

Abstract

PURPOSE:To provide an extremely effective process for producing cyclohexyl acetate in a short time and high yield at a low temperature by the addition reaction of cyclohexene with acetic acid. CONSTITUTION:Cyclohexyl acetate is produced by reacting acetic acid with cyclohexene in the presence of a catalyst consisting of a heteropolyacid composed mainly of a tungsten oxide represented by silicotungstic acid and phosphotungstic acid. The catalytic action can be remarkably improved by adjusting the amount of the ordinary structural water of the heteropolyacid to <=3mol per 1mol of the heteropolyacid.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to a method for producing cyclohexyl acetate. Specifically, the present invention relates to a method for producing cyclohexyl acetate by reacting acetic acid with cyclohexene in the presence of a heteropolyacid mainly composed of tungsten oxide.

0002

BACKGROUND OF THE INVENTION Conventionally, it has long been known that cyclohexyl acetate is produced by esterification reaction of cyclohexanol and acetic acid and reaction of cyclohexanol and acetic anhydride. However, both of these methods use cyclohexanol as a raw material, and the use of cyclohexanol has various drawbacks, such as problems in the production method. In addition, since the esterification reaction is an equilibrium reaction, it is difficult to produce the ester with a high reaction yield, and it is also necessary to take some means to remove by-product water. In addition, although the yield of the ester is high in the method using acetic anhydride, the acetic anhydride used is expensive, and in addition, one molecule of acetic acid is liberated, making it extremely difficult to convert this acetic acid into an anhydride. It has various drawbacks such as.

As a method for solving these problems, a method has recently been proposed in which cyclohexyl acetate is produced by an addition reaction between cyclohexene and acetic acid. For example, JP-A-1-254634 discloses a method for producing cyclohexyl acetate by reacting cyclohexene and acetic acid using a strongly acidic cation exchange resin as a catalyst. The patent states that in order to obtain a high yield of cyclohexyl acetate, it is necessary to carry out the reaction at 130° C. for 5 hours. However, the characteristic of these strongly acidic cation exchange resins is that they generally have a heat resistance temperature of around 100°C, and even those with high heat resistance do not actually exceed 160°C, so cation exchange is not possible under these conditions. The use of resin requires extremely high reaction temperatures and long reaction times. Furthermore, these exchangeable resins also have drawbacks such as low mechanical strength and easy breakage, so there is an extremely high risk of stability as a catalyst, and at the same time, they have low catalytic activity. It is. In addition, in JP-A-1-313447, an addition reaction between acetic acid and cyclohexene was carried out in the presence of water using ZSM-5, a high-silica zeolite, as a catalyst.
In this method, cyclohexyl acetate was finally obtained in a yield of 65% along with cyclohexanol in a yield of 12.5% at a reaction temperature of 120° C. and a reaction time of 4 hours, and the reaction temperature was also high and the catalyst activity was low.

0004

[Problems to be Solved by the Invention] An object of the present invention is to produce cyclohexyl acetate in a short time with high selectivity and high conversion rate by addition reaction between cyclohexene and acetic acid, and to carry out the reaction effectively even in a low temperature range. The product is obtained,
Moreover, it is an object of the present invention to provide a catalyst that can be stably carried out even in a high temperature range.

[0005]

[Means for Solving the Problems] The present inventors investigated an efficient method for producing cyclohexyl acetate, and found that the addition reaction between cyclohexene and acetic acid is an excellent production method. After intensive study to solve problems such as low catalytic activity and durability including mechanical strength and heat resistance of the catalyst, we found that a heteropolyacid mainly composed of tungsten oxide was present in the reaction system as a catalyst. They have discovered that the process can proceed extremely efficiently by doing so, and have completed the present invention. That is, it is a method for producing cyclohexyl acetate, which is characterized by reacting acetic acid and cyclohexene in the presence of a heteropolyacid mainly composed of tungsten oxide, and has the general formula (M1)a(M2)b(W)c (
O) d(H) e (where M1 and M2 represent metal elements, W
represents a tungsten atom, O represents an oxygen atom,
H represents a hydrogen atom. Further, a is an integer of 1 or 2, b is an integer of 0, 1 or 2, c is a positive integer of 20 or less, d is a positive integer of 100 or less, and e is 1
It is a positive integer less than or equal to 0. ) is characterized by using a heteropolyacid mainly composed of tungsten oxide as a catalyst. In these general formulas, M1 is the element symbol P, Si, Co, Mn, Ni, As, Ti, Fe,
It is preferable that the element is an element represented by either V or B, and M2 is an element represented by the element symbol V, and it is particularly preferable to use tungstophosphoric acid and/or tungstosilicic acid.

[0006] In addition, it is sufficient that the heteropolyacid mainly composed of tungsten oxide contains amorphous hydrate and/or water of crystallization of the acid; More preferably, the heteropolyacid has an amount of crystal water adjusted to an average of 3.0 molecules or less per molecule of the heteropolyacid. Furthermore, a heteropolyacid mainly composed of tungsten oxide was heated from 150°C to 500°C.
A heteropolyacid in which the amount of crystallized water contained is adjusted to an average of 3.0 molecules or less per molecule of the heteropolyacid by heat treatment in the temperature range of ℃ or under the flow of an inert gas. A method using an acid is preferred. On the other hand, the amount of crystallization water contained in the heteropolyacid 1
In the case of manufacturing using a heteropolyacid adjusted to an average of 3.0 molecules or less per molecule, the amount of water other than crystal water in the heteropolyacid mainly composed of tungsten oxide is 30.0 per molecule of the heteropolyacid. It is preferable to carry out the reaction in molecules or less.

[0007] Acetic acid and cyclohexene, which are the raw materials in the method of the present invention, do not need to be particularly purified, and commercially available acetic acid and cyclohexene of general reagent purity can be used as they are without any problem. It is preferable to remove moisture. The catalyst used in the method of the present invention is a heteropolyacid mainly composed of tungsten oxide, and has the general formula (
M1)a(M2)b(W)c(O)d(H)e(However, M
1, M2 represents a metal element, 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, c is a positive integer of 20 or less, and d is 100.
is a positive integer below, and e is a positive integer below 10. ) is a heteropolyacid mainly composed of tungsten oxide. In these general formulas, M1 is the element symbol P, Si, Co, Mn, Ni, As, Ti, Fe,
It is preferable that the element is an element represented by either V or B, and M2 is an element represented by the element symbol V, and it is particularly preferable to use tungstophosphoric acid and/or tungstosilicic acid. Specifically, dodecatungstosilicic acid (Si
W12O40H4), a heteropolyacid having a structure in which one or more of the tungsten atoms of dodecatungstosilicic acid are replaced with vanadium atoms, dodecatungstophosphoric acid (P W12O40H3) and one or two of the tungsten atoms of dodecatungstophosphoric acid A heteropolyacid having a structure in which one or more atoms are replaced with vanadium atoms is the most easily available heteropolyacid. However, the method of the present invention is not limited to these heteropolyacids.

[0008] Usually, a heteropolyacid mainly composed of tungsten oxide contains water of crystallization. Here, the crystal water of the heteropolyacid is a general term for water contained in the heteropolyacid when commercially available or prepared, and specifically, when the heteropolyacid is prepared in a water-containing solvent,
These include water that adheres to or is incorporated into heteropolyacid crystals when these are precipitated using a non-solvent or the like, and water that is incorporated into heteropolyacids through adsorption, deliquescence, or the like. For example, in commercially available dodecatungstosilicic acid, the general formula H4 is
It is represented by SiW12O40・nH2O, and commercially available dodecatungstophosphoric acid has the general formula H3P W12O40・n
It is represented by H2O, but nH2O shown in these above formulas
It refers to water molecules incorporated into, adsorbed to, or contained in the crystal structure of a heteropolyacid. Therefore, in the method of the present invention, it means 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. Furthermore, the value can be higher than this due to moisture adsorption, etc. The number of n in these crystal waters can be easily reduced by dehydration treatment such as heating, and it is also possible to set the value of n to zero. In addition, these dehydrated heteropolyacids can easily increase the value of n again by adsorbing water or the like.

A method for adjusting the amount of crystal water contained in a heteropolyacid mainly composed of tungsten oxide as a catalyst used in the present invention to an average of 3.0 molecules or less per molecule of the heteropolyacid will be described. Usually, a heteropolyacid mainly composed of easily available tungsten oxide contains several tens of molecules of water of crystallization per molecule of the above-mentioned heteropolyacid. The crystal water of these heteropolyacids is converted into the heteropolyacid 1.
The method of reducing the average number of molecules per molecule to 3.0 or less is not particularly limited in the method of the present invention, but a heating dehydration operation can be mentioned as a method that is easy to implement. As the heating and dehydration operation, heating in a normal electric furnace (muffle furnace), for example, is recommended. Of course, the method of the present invention is not limited to this device and method. Moreover, the heating temperature is not particularly limited, and the crystal water is the heteropolyacid 1.
As long as the average number of molecules per molecule is 3.0 or less, there is no problem in carrying out the process at any temperature, but in order to carry out the process more effectively, it is preferable to carry out the process at a temperature of 80°C or higher and 500°C or lower, and more preferably. It is recommended to carry out the test at a temperature of 200°C or higher and 450°C or lower. Difficult to dehydrate at low temperatures, 5
If the temperature is 50° C. or higher, there is a possibility that it will become a heteropolyacid anhydride. At this time, there is no particular limitation on the required heating time, and there is no problem as long as the amount of crystallized water falls within the above range, but it is within the range of 10 minutes to 24 hours. For example, if a normal electric furnace is used and the dehydration operation is performed at around 300° C., the amount of crystallization water in the above range can be sufficiently reached in about 3 hours.

[0010] The crystal water is adjusted to an average of 3.0 molecules or less per molecule of the heteropolyacid by carrying out a heating dehydration operation at a heating dehydration temperature and under the condition of flowing a gas inert to the heteropolyacid. When a heteropolyacid is used as a catalyst, the activity of the catalyst is further improved. This operation makes it possible to provide highly effective catalysts.

[0011] Here, the gas to be circulated during the heating dehydration operation may be any gas as long as it is inert to the heteropolyacid mainly composed of tungsten oxide at the heating temperature. There is no problem. Further, even if it is liquid or solid at room temperature, it can be used as long as it is gaseous at heating temperature and is inert to the heteropolyacid. Specific examples include air, argon, nitrogen, helium, hydrogen, aliphatic hydrocarbons, aromatic hydrocarbons, etc., but the method of the present invention is of course not limited to these gases. Further, the flow velocity of the inert gas is not particularly limited, but is 02 to 20 vol/Hr* as the space velocity within the device in terms of gas volume at the heating temperature.
A range of vol is preferred.

According to the method of the present invention, even if the heteropolyacid contains 20 to 30 molecules of structural water per molecule of heteropolyacid, which is the usual amount, good catalytic activity is exhibited;
By adjusting the number of water molecules to an average of 3.0 molecules or less per molecule of the heteropolyacid by dehydration or the like, the heteropolyacid catalyst exhibits significantly high catalytic activity. In addition, this catalyst is extremely stable thermally, making it possible to carry out the method of the present invention with sufficient stability even under high temperature conditions.

The reaction of acetic acid and cyclohexene to cyclohexyl acetate in the method of the present invention proceeds as an addition reaction. At that time, the reaction may be carried out in a homogeneous liquid phase system,
It can also be carried out in a heterogeneous system such as solid phase-gas phase or solid phase-liquid phase. The method of the present invention can also be carried out under normal pressure, reduced pressure, or increased pressure conditions. When carried out at high temperatures, the reaction can be carried out in a liquid phase by applying pressure. Also,
Although the reaction method is not particularly limited, it can be carried out in a continuous method, a batch method, or a semi-batch method.

It is also possible to add solvents or diluents that are inert to the catalyst and reaction reagents (raw materials and products). Specifically, n-butane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-
- Aliphatic saturated hydrocarbons such as decane and their isomers, aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, anisole, cumene, and nitrobenzene, cyclopentane, alkyl-substituted cyclopentanes, alkoxy-substituted cyclo Pentanes, nitro-substituted cyclopentanes, cyclohexane, alkyl-substituted cyclohexanes, alkoxy-substituted cyclohexanes, nitro-substituted cyclohexanes, cycloheptane, alkyl-substituted cycloheptanes, alkoxy-substituted cycloheptanes,
Solvent or dilute alicyclic saturated hydrocarbons such as nitro-substituted cycloheptanes, cyclooctane, alkyl-substituted cyclooctanes, alkoxy-substituted cyclooctanes, nitro-substituted cyclooctanes, nitrogen, air, argon, helium, etc. It can also be used as an agent. When carrying out the reaction under pressurized conditions, it is also possible to pressurize nitrogen, argon, etc. inert to the reaction reagents and catalyst in advance to carry out the reaction as a liquid phase reaction system.

[0015] There are no particular limitations on the quantitative relationship of acetic acid and cyclohexene to be charged when carrying out the reaction in the method of the present invention. The quantitative ratio of acetic acid and cyclohexene is 0.
It ranges from 1 to 100. For example, if you want to achieve a high conversion rate of acetic acid, it is desirable to set the molar ratio of cyclohexene to acetic acid to 1 or more; It is desirable to use 1 or more.

[0016] Further, in carrying out the method of the present invention, the amount of catalyst added is not particularly limited; It is recommended to use 100% by weight, preferably 1 to 50% by weight. If the amount is less than this, the reaction progresses slowly, and if the amount is more than this, the reaction will proceed sufficiently, but it cannot be said to be preferable from an economical point of view. However, it goes without saying that the method of the present invention can be practiced outside this range. When carrying out the method of the present invention, there are no particular limitations on the method of charging the catalyst and reaction reagents, and the catalyst, acetic acid, cyclohexene, etc. may be charged at the same time, or the catalyst may be dissolved or suspended in another solvent, etc. There is no harm in preparing it. Furthermore, methods such as mixing acetic acid and a catalyst in advance before the reaction and then adding cyclohexene, or mixing the catalyst and cyclohexene in advance and then adding acetic acid can also be carried out.

[0017] Here, when carrying out the method of the present invention, the heteropolyacid catalyst mainly composed of tungsten oxide used has an average of 3.0 molecules or less of structural water per molecule of the heteropolyacid. In some cases, the amount of water in the reaction system particularly affects the reaction results. In particular, in order to express a higher catalytic activity than a commercially available catalyst containing several tens of molecules of structured water per molecule of the heteropolyacid,
It is necessary to control the amount of water so that the amount of water other than the structural water possessed by the heteropolyacid is 30 molecules or less per molecule of the heteropolyacid used. If the water content is higher than this, the effect of dehydration of the structural water of the heteropolyacid will not appear. At this time, if the amount of water contained in the commercially available acetic acid and cyclohexene is at most about 100 ppm, and the amount of catalyst added to the reaction system is on the order of %, the present invention When using commercially available acetic acid and cyclohexene in the method, moisture in the reaction system (
The amount of catalyst (excluding water of crystallization) will not exceed the above values.

The reaction temperature in the method of the present invention is not particularly limited and can be carried out over a wide range of temperatures, but is preferably in the range of 0°C to 400°C, more preferably It is recommended to carry out at a temperature of 30°C or higher and 200°C or lower. If the reaction is carried out at too low a temperature, the reaction rate will decrease, and if carried out at too high a temperature, the thermal stability of the reaction reagent such as cyclohexene will be lowered, making it uneconomical. 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 will be extremely short (0.
(about 1 second or less), and a long time (about 24 hours) if the amount of catalyst is small and the temperature is low. After the reaction is completed, the desired product can be obtained by a conventional separation operation such as distillation.

A specific embodiment for carrying out the method of the present invention will be described. There are no particular limitations on the method of carrying out the method of the present invention, but the following methods can be mentioned as easy-to-implement methods. Of course, the method of the present invention is not limited to these methods. (1) Put a predetermined amount of catalyst, acetic acid, and cyclohexene into a glass flask equipped with a stirring device, along with a diluent such as a solvent if necessary, and after installing a reflux device if necessary, heat and stir the reaction. How to do it. (2) A method in which a predetermined amount of catalyst, acetic acid, and cyclohexene are placed in an autoclave together with a medium such as nitrogen or argon if necessary, and then the reaction is carried out with heating and stirring. (3) A method of carrying out a reaction by continuously introducing a predetermined amount of catalyst, cyclohexene and acetic acid into a reactor maintained at a predetermined temperature and pressure in advance, together with a diluent such as a solvent if necessary.

[0020]

[Examples] The method of the present invention will be explained in more detail 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 quantitatively determined by gas chromatography. (2) Determination of crystallized water contained in the catalyst The amount of structural water contained in a heteropolyacid mainly composed of tungsten oxide is determined by heating and dehydrating each heteropolyacid at 500°C, and its weight remains constant. A heteropolyacid in which the amount of crystallization water no longer decreased was 0, in other words, an anhydrous heteropolyacid, and based on this, the amount of structural water was determined for each.

Example 1 70 ml equipped with magnetic stirrer and reflux condenser
Commercially available dodecatungstophosphoric acid (
H4P W12O40.28H2O) 2.0 g, commercially available 99.5% acetic acid (manufactured by Kokusan Kagaku Co., Ltd., special grade) 20.5 g and commercially available 98% cyclohexene (manufactured by Tokyo Kasei Co., Ltd., special grade) 4
．． The flask was placed in an oil bath that had been heated to 70°C in advance, and the reaction was heated and stirred at 70°C for 1.5 hours, then the stirring was stopped, the flask was taken out of the oil bath, and the mixture was heated to room temperature. After cooling, the reaction solution was quantified. As shown in Table 1, the result was a cyclohexyl acetate yield of 33.4%.
(selectivity 97.3%), and the conversion rate of cyclohexene was 34.3%.

Comparative Example 1 H-Z was used instead of dodecatungstophosphoric acid as a catalyst.
The reaction was carried out under the same reaction conditions as in Example 1 except that 2.0 g of SM5 zeolite catalyst was used. As a result, no production of cyclohexyl acetate was observed, and only the raw materials cyclohexene and acetic acid were recovered.

Example 2 A reaction for producing cyclohexyl acetate from cyclohexene and acetic acid was carried out under the same conditions as in Example 1 except that the reaction time was changed to 3 hours. As shown in Table 1, the amount of cyclohexyl acetate produced increased as the reaction time increased.

Example 3 The catalyst was commercially available dodecatungstosilicic acid (H4SiW1
The reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 1, such as the weight of the catalyst used, except that 2O40.25H2O) was used. The results are listed in Table 1.

Example 4 A reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 3 except that the reaction time was changed to 3 hours. The results are in Table 1
It was shown to.

Example 5 5.0 g of the above commercially available dodecatungstosilicic acid, 61.5 g of the above commercially available acetic acid, and 13.5 g of the above commercially available cyclohexene were placed in a 200 ml autoclave, and 5 kg/g of the above commercially available cyclohexene was added.
After injecting nitrogen to a Cm2 gauge pressure, 10
The reaction was heated and stirred at 0° C. for 1 hour. As shown in Table 2, the results showed that cyclohexyl acetate was produced in a very high yield.

[0027]

[Table 1] ──────────────────────────
────────────
Cy-Hex Cy-HexO
Ac
Conversion rate (%) Yield (%)
Selection rate (%) ──────
──────────────────────────
──── Example 1 34.3
33.4 97.3
Example 2 50.6
50.2 99.2
Example 3 5
7.2 54.8
95.8 Example 4
71.2 71.2
100.0 Example 5
88.1 87.
6 99.4 ──
──────────────────────────
──────── However, Cy-Hex in the table represents cyclohexene, and Cy-HexOAc represents cyclohexyl acetate.

Example 6 Preparation of catalyst for heated dehydration of dodecatungstophosphoric acid The commercially available dodecatungstophosphoric acid described above was heated and dehydrated in an electric furnace (muffle furnace) at a predetermined temperature and for a predetermined time as shown in Table 2. As a result, the composition of crystal water in dodecatungstophosphoric acid showed the values listed in Table 2. However, the number of molecules of crystal water present per molecule of dehydrated dodecatungstophosphoric acid obtained in each case is shown as the value n' in the table.

[0029]

[Table 2] ──────────────────────────
──────────
Heating temperature (℃) Heating time (hours)
n' ──────────────
────────────────────────
Catalyst 1 350
3.0 0
Catalyst 2 40
0 3.0
0 catalyst 3
300
3.0 0
Catalyst 4 250
1.0
1.4 Catalyst 5
250 0.5
3.0 Catalyst 6 200
0.25 4.8
Catalyst 7 120
1.0
8.0 ──────────────────
──────────────────── Example 7 Acetic acid and cyclohexene were synthesized using the same equipment and conditions as in Example 1 except that the above catalyst 1 was used as the heteropolyacid catalyst. The reaction was carried out. As shown in Table 3, the activity of the catalyst was significantly improved.

Example 8 A reaction between acetic acid and cyclohexene was carried out using the same apparatus and conditions as in Example 7, except that the above catalyst 2 was used as the heteropolyacid catalyst. As shown in Table 3, the results showed that even if the dehydration temperature during catalyst preparation was increased, the catalyst activity was hardly affected, and extremely high catalyst activity was confirmed.

Example 9 The reaction was carried out under the same conditions as in Example 7 except that Catalyst 3 was used as the catalyst. As shown in Table 3, the reaction results were similar to those of Catalyst 1 and Catalyst 2.

[0032] From this, in order to significantly improve the activity of the catalyst by dehydrating a heteropolyacid mainly composed of tungsten oxide, the amount of crystal water possessed by the heteropolyacid is more important than the dehydration temperature. I understand.

Example 10 The reaction was carried out under the same conditions as in Example 7 except that Catalyst 4 was used as the catalyst. The results are shown in Table 3.

Example 11 The reaction was carried out under the same conditions as in Example 7 except that Catalyst 5 was used as the catalyst. The results are shown in Table 3.

Example 12 A reaction between acetic acid and cyclohexene was carried out under exactly the same conditions as in Example 7 except that Catalyst 6 was used as the catalyst. As shown in Table 3, no effect of improving the catalytic activity was observed due to the dehydration treatment of the heteropolyacid.

Example 13 A reaction was carried out under exactly the same conditions as in Example 7 except that Catalyst 7 was used as the catalyst. As shown in Table 3, the results showed the same catalytic activity as commercially available dodecatungstophosphoric acid.

Example 14 A reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 7 except that the amount of catalyst 1 used was reduced from 2 g to 0.5 g. The results are listed in Table 3.

Example 15 The reaction was carried out under the same conditions as in Example 14 except that the reaction time was changed to 3 hours. As shown in Table 3, the amount of cyclohexyl acetate produced increased as the reaction time increased, indicating that there was no deterioration of the catalyst.

Example 16 2.0 g of catalyst 1, 61.5 g of acetic acid and 13.5 g of cyclohexene were placed in a 200 ml autoclave, and the inside of the autoclave was pressurized with nitrogen to a gauge pressure of 5 kg/cm2. Acetic acid cyclohexylation reaction was carried out at ℃ for 1 hour. The results are listed in Table 3.

Example 17 A reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 16 except that the reaction temperature was 130° C. and the reaction time was 0.5 hours. As shown in Table 3, cyclohexyl acetate was produced in high yield in a short period of time.

[0041]

[Table 3] ──────────────────────────
────────── Catalyst


n'
Cy-Hex Cy-HexO
Ac
Conversion rate (%) Yield (%
) Selection rate (%)────────────────
────────────────────Example 7
1 0 81.7
80.6 97.3 Example 8
2 0 80.
9 80.5 99.5 Example 9 3 0 8
1.2 80.5 99.1
Example 10 4 1.4 82
．． 6 80.8 97.8 Example 11 5 3.0 70.
5 68.0 96.5 Example 12 6 4.8 9.
4 8.9 94.9 Example 13 7 8.0 37.
1 35.1 94.5 Example 14 1 0 41
．． 3 40.2 97.4 Example 15 1 0 6
3.4 62.3 98.2
Example 16 1 0
89.5 88.9 99.3
Example 17 1 0
91.2 90.4 99.1
────────────────────────
────────────The amount of catalyst used was 2.0 g each except for Examples 14 and 15, and 0.5 g for Examples 14 and 15.
It is g. Cy-Hex in the table is cyclohexene, Cy
-HexOAc represents cyclohexyl acetate. Further, n' is the number of crystal water molecules contained per molecule of the dehydrated heteropolyacid used as the catalyst.

Example 18 Preparation of dehydrated heteropolyacid catalyst The above commercially available dodecatungstosilicic acid (containing 25 molecules per molecule of heteropolyacid as structured water) was placed in a muffle furnace and heated to a predetermined temperature as shown in Table 4. Dehydration was performed by heating for a period of 2 hours. The crystal water contained in each obtained dodecatungstosilicic acid is expressed as the number of molecules n' per molecule of the heteropolyacid.

[0043]

[Table 4] ──────────────────────────
──────────
Heating temperature (℃) Heating time (hours)
n' ──────────────
────────────────────────
Catalyst 8 370
3.0 0
Catalyst 9 42
0 1.0
0 catalyst 1
0 300 3.0
0
Catalyst 11 250
2.0
1.7 Catalyst 12 25
0 0.75
3.0 Catalyst 13
250 0.5
4.0
Catalyst 14 180
0.25 5.8
Catalyst 15 150
0.75
12.7 Catalyst 16 100
1.0
21.5 ────────────
────────────────────────

[
Example 19 In Example 3, the reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 3, except that the commercially available dodecatungstosilicic acid was replaced with Catalyst 8 (2.0 g charged). Ta. As shown in Table 5, extremely high catalytic activity was observed.

Example 20 The reaction was carried out under the same conditions as in Example 19 except that Catalyst 9 was used as the catalyst. As shown in Table 5, the results show that even if the dehydration temperature is increased, the reaction results are hardly affected.

Example 21 The reaction was carried out under the same conditions as in Example 19 except that the catalyst was replaced with Catalyst 10. As shown in Table 5, lowering the dehydration temperature during catalyst preparation has almost no effect on the reaction results.

Example 22 A reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 19 except that Catalyst 11 was used as the catalyst. The results are shown in Table 5.

Example 23 A reaction was carried out under the same conditions as in Example 19 except that Catalyst 12 was used as the catalyst. The results are shown in Table 5.

Example 24 A reaction for producing cyclohexyl acetate was carried out under the same conditions as in Example 19 except that Catalyst 13 was used as the catalyst. As shown in Table 5, only a very small amount of cyclohexyl acetate was confirmed to be produced.

Example 25 A reaction was carried out under the same conditions as in Example 19, except that Catalyst 14 was used as the catalyst. As shown in Table 5, the reaction results were poor as in Example 24.

Example 26 A reaction was carried out under the same conditions as in Example 19, except that Catalyst 15 was used as the catalyst. As shown in Table 5, no catalytic activity effect was observed due to the dehydration of the heteropolyacid.

Example 27 The reaction was carried out under the same conditions as in Example 19 except that the catalyst was replaced with Catalyst 16. As shown in Table 5, no effect of heteropolyacid dehydration was observed.

[0053] From this result, since the amount of structural water contained in the heteropolyacid is 3.0 molecules or less per molecule of the heteropolyacid, the heteropolyacid It can be seen that it exhibits extremely high catalytic activity.

Example 28 Example 19 except that the amount of catalyst 8 used was 0.5 g.
The reaction was carried out under the same conditions as . The results are shown in Table 5.

Example 29 The reaction was carried out under the same conditions as in Example 28 except that the reaction time was changed to 3 hours. The results are shown in Table 5. The amount of cyclohexyl acetate produced increased as the reaction time increased, indicating that the catalyst did not deteriorate.

Example 30 2.0 g of catalyst 8, 61.5 g of acetic acid and 13.5 g of cyclohexene were placed in a 200 ml autoclave, and the inside of the autoclave was pressurized with nitrogen to a gauge pressure of 5 kg/cm2. Acetic acid cyclohexylation reaction was carried out at 100°C for 1 hour. The results are listed in Table 5.

Example 31 A reaction was carried out under the same conditions as in Example 24, except that the reaction temperature was 130° C. and the reaction time was 0.5 hours. As shown in Table 5, cyclohexyl acetate was produced in a high yield in a short period of time.

[0058]

[Table 5] ──────────────────────────
────────── Catalyst n' Cy-Hex Cy
-HexOAc
Conversion rate (%)
Yield (%) Selectivity (%)────────────
────────────────────────Example 19 8 0 8
7.2 86.2 98.9
Example 20 9 0
86.8 86.0 99.1
Example 21 10 0
85.9 85.3 99.3
Example 22 11 1.7 87
．． 5 85.7 97.9 Example 23 12 3.0 72.8
71.6 98.3 Example 24 13 4.0 14.2
9.1 64.8 Example 2
5 14 5.8 15.6
12.1 77.6 Example 26
15 12.7 56.2
51.8 92.8 Example 27
16 21.5 55.8 51.
0 91.4 Example 28 8
0 43.7 42
．． 5 97.3 Example 29
8 0 73.8 7
2.9 98.9 Example 30
8 0 91.6
91.1 99.5 Example 31
8 0 95.2
94.4 99.2 ────────
──────────────────────────
---However, the amount of each catalyst used was 0.5 in Examples 28 and 29.
g was used, and 2.0 g was used in all other examples.

Example 32 Preparation of dodecatungstophosphoric acid dehydration catalyst (2) The above commercially available dodecatungstophosphoric acid was placed in a muffle furnace with an internal volume of 8 liters and capable of introducing and discharging gases, and the various types shown in Table 6 were heated. Thermal dehydration was performed at a predetermined temperature and for a predetermined time while flowing gas at a predetermined flow rate. Table 6 shows the number of molecules (n') of crystalline water per molecule of tungstophosphoric acid contained in each of the obtained tungstophosphoric acids.

[0060]

[Table 6] ──────────────────────────
────────── Gas flow rate (Nl/Hr) Temperature (℃) Time (Hr)
n' ────────────────────
────────────────Catalyst 17 Ar
5.0 350
3 0 catalyst 1
8 Ar 5.0 4
00 1 0
Catalyst 19 Ar 5.0
300 3
0 Catalyst 20 Ar 5.
0 250 1
1.3 Catalyst 21 Ar
5.0 250
0.5 2.9 Catalyst 22 Ar
35.0 350
3 0 catalyst 23
Air 35.0 350
3 0
Catalyst 24 He 35.0
350 3 0
────────────────────
──────────────── However, Ar in the table
represents argon and He represents helium.

Example 33 Catalyst 17 was prepared from the above commercially available dodecatungstophosphoric acid.
The reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 1, except that the amount added was changed to 2.0 g. As shown in Table 7, the results show that by heating and dehydrating dodecatungstophosphoric acid under argon flow, an extremely highly active catalyst can be obtained.

Example 34 The reaction was carried out under the same conditions as in Example 33 except that catalyst 18 was used. The results are listed in Table 7.

Example 35 The reaction was carried out under the same conditions as in Example 33 except that Catalyst 19 was used as the catalyst. The results are shown in Table 7.

[0064] This shows that the dehydration temperature has almost no effect on the catalyst activity.

Example 36 The reaction was carried out under the same conditions as in Example 33 except that Catalyst 20 was used as the catalyst. The results are shown in Table 7.

Example 37 The reaction was carried out under the same conditions as in Example 33 except that Catalyst 21 was used as the catalyst. The results are listed in Table 7.

Example 38 The reaction was carried out under the same conditions as in Example 33 except that Catalyst 22 was used instead of the catalyst. The results are listed in Table 7. This shows that the gas inflow rate does not affect the catalyst activity.

Example 39 The reaction was carried out under the same conditions as in Example 33 except that Catalyst 23 was used instead of the catalyst. The results are shown in Table 7.

Example 40 The reaction was carried out under the same conditions as in Example 33 except that Catalyst 24 was used instead of the catalyst. The results are listed in Table 7. This shows that argon, helium, and air circulation heating dehydration is effective.

[0070]

[Table 7] ──────────────────────────
────────── Catalyst
n' Cy-Hex Cy
-HexOAc
Conversion rate (%)
Yield (%) Selectivity (%)────────────
────────────────────────Example 33 17 0 86
．． 7 85.4 98.5 Example 34 18 0 85
．． 9 85.3 99.3 Example 35 19 0 86
．． 2 84.6 98.1 Example 36 20 1.3 87.6
85.0 97.1 Example 37 21 2.9 75.8
73.3 96.7 Example 38
22 0 86.9
85.4 98.3 Example 39
23 0 87.5
85.3 97.5 Example 40
24 0 87.2
85.8 98.4 ──────
──────────────────────────
───── However, Cy-Hex in the table represents cyclohexene, and Cy-HexOAc represents cyclohexyl acetate.

Example 41 Catalyst preparation by heating dehydration of dodecatungstosilicic acid under gas flow The commercially available dodecatungstosilicic acid was placed in the same muffle furnace as in Example 27, and each gas was introduced at a predetermined flow rate. Heat dehydration was performed at a predetermined temperature and for a predetermined time while circulating. Table 8 lists the prepared catalysts, preparation conditions, and the number of crystal water molecules (n') contained per molecule of the prepared heteropolyacid catalyst.

[0072]

[Table 8] ──────────────────────────
────────── Gas
Flow rate (Nl/Hr) Temperature (℃) Time (Hr)
n' ────────────────────
────────────────Catalyst 25 Ar
5.0 370
3 0 catalyst 2
6 Ar 5.0
420 1 0
Catalyst 27 Ar 5.0
300 3
0 Catalyst 28 Ar
5.0 250
1 1.3 Catalyst 29 Ar
5.0 250
0.5 2.9 Catalyst 30 Ar
35.0 350
3 0 catalyst 31
Air 35.0
350 3 0
Catalyst 32 He 35.0
350 3
0 ────────────────────
─────────────── In the table, Ar represents argon and He represents helium.

Example 42 A reaction between acetic acid and cyclohexene was carried out under the same conditions as in Example 3, except that the commercially available dodecatungstosilicic acid catalyst in Example 3 was replaced with Catalyst 25 (2.0 g added). As shown in Table 9, it was found that the tungstosilicic acid catalyst heated and dehydrated under gas flow had extremely high catalytic activity.

Example 43 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 26 was used instead of the catalyst. The results are shown in Table 9.

Example 44 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 27 was used instead. The results are listed in Table 9.

Example 45 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 28 was used instead of the catalyst. The results are listed in Table 9.

Example 46 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 29 was used instead of the catalyst. The results are shown in Table 9.

Example 47 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 30 was used instead of the catalyst. As shown in Table 9, changing the gas flow rate does not affect the activity of the catalyst.

Example 48 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 31 was used as the catalyst. The results are shown in Table 9.

Example 49 The reaction was carried out under the same conditions as in Example 42 except that Catalyst 32 was used instead of the catalyst. The results are shown in Table 9. As a result,
It can be seen that argon, helium, and air are effective gases to be circulated during the heating and dehydration preparation of the catalyst.

[0081]

[Table 9] ──────────────────────────
────────── Catalyst
n' Cy-Hex Cy
-HexOAc
Conversion rate (%)
Yield (%) Selectivity (%)────────────
────────────────────────Example 42 25 0 92.6
90.5 97.8 Example 43 26 0 91.9
90.2 98.1 Example 44 27 0 90.6
90.0 99.4 Example 45 28 1.3 92.2
90.7 98.4 Example 46 29 2.9 77.3
74.4 96.2 Example 47
30 0 91.8
90.2 97.7 Example 48
31 0 93.1
90.8 97.5 Example 49
32 0 91.5
90.3 98.7 ──────
──────────────────────────
────── However, Cy-Hex is cyclohexene,
Cy-HexOAc represents cyclohexyl acetate.

Example 50 After charging the catalyst, acetic acid and cyclohexene so that the amount of water in the reaction system was 1.1 molecules per molecule of catalyst 17 (0 crystal water), pure water was added, The reaction was carried out under all other conditions as in Example 33. The results are listed in Table 10. For reference, Table 10 includes Example 33.
The results are also shown.

Example 51 Pure water was added in the same manner as in Example 50 so that the amount of water in the reaction system was 4.5 molecules per molecule of catalyst 17 (0 crystal water), and other conditions were All reactions were carried out under the same conditions as in Example 28. The results are shown in Table 10.

Example 52 Pure water was added in the same manner as in Example 50 so that the amount of water in the reaction system was 10.2 molecules per molecule of catalyst 17 (0 crystal water), and all other conditions were The reaction was carried out under the same conditions as in Example 28. The results are shown in Table 10.

Example 53 Pure water was added in the same manner as in Example 50 so that the amount of water in the reaction system was 29.2 molecules per molecule of catalyst 17 (0 crystal water), and all other conditions were The reaction was carried out in the same manner as in Example 28. The results are shown in Table 10.

Example 54 Pure water was added in the same manner as in Example 45 so that the amount of water in the reaction system was 29.2 molecules per molecule of catalyst 17 (0 crystal water), and all other conditions were the same. The reaction was carried out in the same manner as in Example 33. As shown in Table 10, the effect of catalyst dehydration on improving activity was no longer observed.

Example 55 After the catalyst, acetic acid, and cyclohexene were charged so that the amount of water other than crystal water of catalyst 20 (n'=1.3) in the reaction system was 10.2 molecules per molecule of catalyst. The reaction was carried out under the same conditions as in Example 36 except that pure water was added. The results are shown in Table 10.

Example 56 The reaction was carried out under the same conditions as in Example 55 except that the catalyst was replaced with catalyst 21 (n'=2.9). The results are shown in Table 10.

Example 57 In Example 42, pure water was added in the same manner as in Example 50 so that the water content was 1.1 molecules per molecule of catalyst 25 (0 crystal water), and other The reaction was carried out under the same conditions as in Example 42. The results are shown in Table 10. Note that the results of Example 42 are also described.

Example 58 All conditions were the same as in Example 57 except that the amount of pure water added was 4.5 molecules per 1 molecule of catalyst 25 (0 crystal water). The reaction was carried out. The results are shown in Table 10.

Example 59 The reaction was carried out under the same conditions as in Example 57 except that the amount of pure water added was 10.5 molecules per molecule of catalyst. The results are listed in Table 10.

Example 60 The reaction was carried out under the same conditions as in Example 57 except that the amount of pure water added was 29.2 molecules per molecule of catalyst. The results are shown in Table 10.

Example 61 The reaction was carried out under the same conditions as in Example 57 except that the amount of pure water added was 35.4 molecules per molecule of catalyst. As shown in Table 10, no effect of improving the activity by heating and dehydrating the catalyst was observed.

Example 62 The reaction was carried out under the same conditions as in Example 45 except that the amount of water other than crystal water contained in catalyst 28 (n'=1.3) was 10.2 molecules per molecule of catalyst. I did it. The results are shown in Table 10.

Example 63 The reaction was carried out under the same conditions as in Example 62 except that Catalyst 29 was used instead of the catalyst. The results are shown in Table 10.

[0096]

[Table 10] ──────────────────────────
────────── Catalyst Moisture CyHex C
yHexOAc
(a) Conversion rate %
Yield% Selectivity% ──────
──────────────────────────
────Example 33 17 0.02
86.7 85.4 98.5
Example 50 17 1.1
86.9 85.7 98.6 Example 51 17 4.5 82
．． 1 80.6 98.2 Example 52 17 10.2 78.3
77.6 99.1 Example 53
17 29.2 46.9
45.3 96.6 Example 54
17 34.3 33.7 32.
9 97.6 Example 55 20
10.2 78.5 78.0
99.4 Example 56 21 10
．． 2 77.2 76.1 9
8.6 Example 42 25 0.0
2 92.6 90.5 97.8
Example 57 25 1.1
91.8 90.3 98.4
Example 58 25 4.5
88.9 85.7 96.4
Example 59 25 10.5 80
．． 3 78.8 98.1 Example 60 25 29.0 67.2
65.5 97.5 Example 61
25 35.4 48.4
46.2 95.5 Example 62
28 10.2 80.5 79.
4 98.6 Example 63 29
10.2 71.2 69.1
97.1 ────────────────
──────────────────────

009
7]

[Effects of the Invention] According to the method of the present invention, cyclohexyl acetate can be produced extremely efficiently through the addition reaction of acetic acid and cyclohexene in the presence of a heteropolyacid mainly composed of tungsten oxide. . In addition,
This method overcomes the drawbacks of conventional catalysts, such as low activity and low heat resistance, and becomes an extremely important method for producing cyclohexyl acetate. Furthermore, the heteropolyacid is subjected to a dehydration treatment such as heating, and the amount of crystal water or structured water (hereinafter referred to as "structured water") that the heteropolyacid normally has is reduced to an average of 3.0 molecules per molecule of the heteropolyacid. We have also discovered that extremely high reaction efficiency can be achieved by using the heteropolyacid prepared in advance as a catalyst, and cyclohexyl acetate can be obtained with high selectivity and high conversion under extremely mild conditions and in a short period of about 1 hour. Furthermore, it has become possible to carry out the reaction stably and effectively even under high temperature conditions. It is used to produce raw materials such as cyclohexanol, which is useful as an intermediate raw material for phenol, adipic acid, and nylon, and cycloalkanol aliphatic carboxylic acid esters, which are useful as special solvents.

Claims (9)

[Claims] 1. A method for producing cyclohexyl acetate, which comprises reacting acetic acid and cyclohexene in the presence of a heteropolyacid mainly composed of tungsten oxide. 2. A method for producing cyclohexyl acetate by an addition reaction of cyclohexene with acetic acid, comprising the general formula (M1)a(M2)b(W)c(O)d(H)e(
However, M1 and M2 represent metal elements, W 2 represents a tungsten atom, O 2 represents an oxygen atom, and H 2 represents a hydrogen atom. Furthermore, a is an integer of 1 or 2, b is an integer of 0, 1, or 2, 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. It is a positive integer. 2. The method according to claim 1, wherein a heteropolyacid mainly composed of tungsten oxide represented by: ) is used as a catalyst. [Claim 3] M1 is an element symbol of P, Si, Co, M
3. The method according to claim 2, wherein M2 is an element represented by any one of n, Ni, As, Ti, Fe, V, and B, and M2 is an element represented by V as an element symbol. 4. The method according to claim 1, wherein the heteropolyacid mainly composed of tungsten oxide contains an amorphous hydrate and/or water of crystallization of the acid. 5. The method according to claim 1, wherein the heteropolyacid containing tungsten oxide as a main component has an amount of crystallization water adjusted to an average of 3.0 molecules or less per molecule of the heteropolyacid. 6. By heat-treating a heteropolyacid mainly composed of tungsten oxide in a temperature range of 150°C to 500°C, the amount of crystal water contained is on average 3.0 molecules per molecule of the heteropolyacid. The method according to claim 5, which is a heteropolyacid prepared as follows. 7. By heat-treating a heteropolyacid mainly composed of tungsten oxide under the flow of a gas inert to the heteropolyacid, the amount of crystallization water contained per molecule of the heteropolyacid is reduced. The method according to claim 5, wherein the heteropolyacid is adjusted to have an average size of 3.0 molecules or less. 8. Adding an amount of water other than crystallization water to a heteropolyacid mainly composed of tungsten oxide.
6. The method according to claim 5, wherein the reaction is carried out at 30.0 molecules or less per molecule. 9. The method according to claim 1, wherein the heteropolyacid mainly composed of tungsten oxide is tungstophosphoric acid and/or tungstosilicic acid.