JPH05239043A - Separation of acetic acid from cyclohexene oxide - Google Patents

Abstract

PURPOSE:To efficiently separate acetic acid in the crude reaction liquor from cyclohexene oxide produced by direct oxidation using an organic peracid and through a simple process on an industrial scale. CONSTITUTION:Cyclohexene is epoxidized with peracetic acid to produce cyclohexene oxide. Then, the resulting acetic acid and the cyclohexene are separated from each other from the crude reaction liquor by distillation in the presence of a compound azeotropic with the acetic acid. Owing to the use of this compound, cyclohexene oxide can efficiently be separated and purified, which has been very hard to separate from acetic acid by distillation because of its small difference in boiling point from acetic acid and its high reactivity therewith.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for separating acetic acid and cyclohexene oxide.

Cyclohexene oxide is an important compound as a raw material for dyes, pharmaceutical intermediates, and acaricides related to agricultural chemicals.

[0003]

2. Description of the Related Art Heretofore, as a method for producing cyclohexene oxide, (1) by reacting cyclohexene with hypochlorous acid,
After producing 2-chlorocyclohexanol, a method of treating with an alkali to epoxidize it (for example, BUL
L. SOC. CHIM (4), 37, 1454 (192
5) etc.) (2) A method of directly oxidizing with an organic peracid such as performic acid, peracetic acid or perpropionic acid (for example, Journal of Japan Society of Oil Chemistry, Vol. 36, No. 6, P. 436-440, etc. )
(3) Hydrogen peroxide or hydroperoxide in the presence of a catalyst
A method of oxidizing with an oxide (for example, JP-A-49-124)
003, JP-A-52-211, and JP-A-62-23077.
8) (4) Liquid phase air oxidation in the presence of a catalyst such as a molybdenum complex (for example, JP-A-50-149645 and JP-A-52-3036) is known.

Among the above methods, the method (1) using hypochlorous acid is industrially carried out. However, since chlorine is present in the reaction system, there is a problem of equipment corrosion and a problem in products. There was a problem such as chlorine contamination. Moreover, since the reaction is carried out in two stages, the process is complicated for the simple reaction.

In the method (2) of directly oxidizing with an organic peracid, the reaction proceeds in a single stage and the reaction rate is very fast, and since no catalyst is used, the catalyst separation is carried out when industrially carried out. It has a great advantage such as no process required.

[0006] The inventors of the present invention, when carrying out the above-mentioned industrial processes, use a process-simple method of direct oxidation with an organic peracid, which is one of the organic peracids actually used industrially. , Peracetic acid, was found, conditions for obtaining cyclohexene oxide with a high reaction yield were found, and a patent has already been applied for.

[0007]

However, when the method for purifying cyclohexene oxide produced by the reaction was examined, it was found that the product cyclohexene oxide could not be obtained in good yield by the ordinary purification method by distillation.

[0008]

OBJECT OF THE INVENTION The object of the present invention is to carry out, when industrially carried out, the cyclohexene oxide produced by the process of direct oxidation with an organic peracid and the acetic acid present in the reaction crude liquid. It is to develop a method for efficient separation.

[0009]

That is, the present invention is
"Acetic acid and cyclohexene oxide are characterized by distilling and separating acetic acid and cyclohexene oxide in a high yield from a reaction crude liquid prepared by epoxidizing cyclohexene with peracetic acid to produce cyclohexene oxide in the presence of a compound azeotropic with acetic acid. The method of separating oxides ". The method of distilling and separating acetic acid and cyclohexene oxide of the present invention in high yield is described in detail below.

The present inventors have previously proposed and patented a method for efficiently producing cyclohexene oxide from cyclohexene by a one-step reaction. However, when the produced cyclohexene oxide is separated by an ordinary distillation method, it is epoxidized. Acetic acid contained in peracetic acid (760 m
mHg boiling point 118 ° C) and acetic acid by-produced after epoxidation reaction and generated cyclohexene oxide (760 mmH
Boiling point difference with boiling point 129 ° C in g (about 1 at 760 mmHg)
(1 ° C.) is small, the distillation yield is remarkably low. To make matters worse, the reactivity between acetic acid and cyclohexene oxide is high, which results in the reaction during the distillation to further deteriorate the distillation yield (reaction formula 1).

An outline of the method for separating acetic acid and cyclohexene oxide is as follows. In the first distillation column, acetic acid is distilled as an azeotropic mixture from the reaction crude liquid and the compound azeotropic with acetic acid, and cyclohexene is removed. The oxide is obtained as a mixture in the kettle liquor (or bottoms). Then, the cyclohexene oxide obtained as a mixture in the kettle liquid (or bottom liquid) of the first column is purified in the second column and thereafter. In the present invention, acetic acid is distilled as an azeotrope from the reaction crude liquid and the compound azeotropic with acetic acid in the first distillation column to the top of the column, and cyclohexene oxide is added to the kettle liquid (or bottom liquid). In particular, it relates to a method for separating acetic acid and cyclohexene oxide to obtain a mixture.

The contents of the invention will be described below step by step.

The amount of the compound azeotropically azeotroping with acetic acid for cyclohexene oxide in the crude reaction liquid should be at least 1 mol times the amount required for the azeotropic composition at the distillation pressure (the azeotropic composition varies depending on the pressure). It is used in an amount exceeding the above range, more preferably in a range of 1.1 to 3 times the molar amount.

If the amount is less than 1 mol times, acetic acid that is not distilled off azeotropically falls into the kettle having the highest temperature and reacts with cyclohexene oxide in (Reaction formula 1) to significantly deteriorate the cyclohexene oxide distillation yield. .. On the other hand, if the amount of the compound that is azeotropic with acetic acid is too large, it is not preferable because the heating vapor cost is increased during the azeotropic separation of acetic acid and the purification of cyclohexene oxide.

The compound for azeotroping with acetic acid may be charged in the same stage as the raw material reaction crude liquid or in a separate stage, but more preferably, it is azeotropic with acetic acid having a boiling point lower than that of acetic acid. In the case of a compound, it is preferable to charge the raw material reaction crude liquid in a stage lower than the stage. Toluene (760 mmHg at azeotropic temperature 11
0.6 ° C, azeotropic composition 28.1 wt% acetic acid / toluene 7
1.9 wt%), ethylbenzene (azeotropic temperature 114.65 ° C. at 760 mmHg, azeotropic composition 66 wt% acetic acid / ethylbenzene 34 wt%), o-xylene (760 mmH)
azeotropic temperature 116.0 ° C., azeotropic composition acetic acid 76 wt%
o-xylene 24 wt%), m-xylene (760 mm
Azeotropic temperature at Hg of 115.35 ° C, azeotropic composition of acetic acid 72.5
wt% · m-xylene 27.5 wt%), p-xylene (azeotropic temperature 115.25 ° C. at 760 mmHg, azeotropic composition acetic acid 72 wt% · p-xylene 28 wt%), n-heptane (azeotropic temperature 95 at 760 mmHg). C., azeotropic composition 17% by weight acetic acid / n-heptane 83% by weight), cyclohexene (azeotropic temperature 81.8 ° C. at 760 mmHg, azeotropic composition acetic acid 6.5% by weight, cyclohexene 93.5% by weight) and the like.

The distillation pressure is preferably as low as possible to reduce the temperature of the reboiler and in order to suppress side reactions, the distillation pressure is preferably as low as possible, but it depends on the capacity of the condenser and the type of refrigerant, and is usually 10 to 100 mmHg. Is performed at a column top pressure of, and more preferably at a column top pressure of 20 to 50 mmHg. If the distillation pressure is lowered too much, depending on the capacity of the condenser and the type of refrigerant, low-boiling substances (particularly low-boiling solvent of peracetic acid (such as ethyl acetate) and unreacted cyclohexene) cannot be collected, so the condenser- It is necessary to select a distillation pressure that is suitable for the capacity and the type of refrigerant.

The distillation system may be either a batch system or a continuous system, but since the temperature of the kettle including the inside of the distillation column is the highest, the residence time in the kettle is too long in the batch system, so that (reaction formula 1) It is preferable to carry out the continuous distillation because the side reaction of (3) easily occurs and the yield of cyclohexene oxide is lower than that in the continuous system.

Further, even in the case of the continuous system, the capacity of the thermosiphon type reboiler depends on the amount of the raw material crude liquid charged and the column diameter of the distillation column, but it is preferable to use as small a volume as possible. Therefore, in some cases, instead of the thermosiphon reboiler, an evaporator such as a thin film evaporator that can shorten the residence time of the liquid as much as possible may be used as the reboiler.

The cyclohexene oxide containing high-boiling substances from which acetic acid has been removed by azeotropic distillation and the compound azeotroping with excess acetic acid are further separated by batch distillation or continuous distillation to separate the compounds azeotropic with excess acetic acid and the high-boiling substances. , Pure cyclohexene oxide is obtained.

Specifically, in the case of batch distillation, a compound that is azeotropic with excess acetic acid is distilled off, and then cyclohexene oxide is distilled off to obtain a product. Further, in the case of continuous distillation, a compound which is azeotropic with excess acetic acid is distilled off in the first column, and a bottom product is charged into the second column to distill cyclohexene oxide to obtain a product. Even if the second column is a batch distillation column,
It may be a continuous distillation column. In addition, even if cyclohexene oxide is obtained by performing batch distillation (or continuous distillation) by the above method after removing high boiling substances using a thin film evaporator or the like before batch distillation (or continuous distillation). good.

Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[0022]

Example 1 1010 g of cyclohexene was placed in a 10 L glass round-bottomed flask equipped with a hot water bath, a stirrer, a thermometer, a condenser and a pump for continuously charging peracetic acid, and the mixture was immersed in the hot water bath while stirring with a stirrer. The temperature of the liquid in the reactor was raised to 30 ° C. After heating, peracetic acid 2
3830 g of an ethyl acetate solution containing 9.2 wt% and about 6 wt% of acetic acid was charged over 2 hours while keeping the liquid temperature in the reactor at 30 ° C., and further maintained at 30 ° C. for 1 hour.

After completion of the reaction, the reaction crude liquid in the reactor was taken out and analyzed by gas chromatography.
As a result, the conversion of cyclohexene was 97.2%, and the yield of cyclohexene oxide based on cyclohexene was 9%.
At 4.2%, the selectivity of cyclohexene oxide based on cyclohexene was 96.9%.

The raw material reaction crude liquid produced by the above procedure was used in the following purification experiment. Since acetic acid and cyclohexene oxide react with each other during storage and change with time, the concentration of cyclohexene oxide in the raw material reaction crude liquid is I use a slightly lowered one.

[0025]

Example 2 Using a 40 mmφ 40-stage Oldershaw distillation column equipped with a thermosyphon type reboiler having a capacity of 100 ml, 66.5 g of a reaction crude liquid obtained by epoxidizing cyclohexene with peracetic acid at the 20th stage from the kettle was used. / Hr, and toluene at the 10th stage from the kettle was charged at 62.6 g / hr to control the column top pressure to 30 mmHg.
Continuous distillation was carried out with a reflux ratio of 1. As a result, 108.0 g / hr of a liquid containing 11.7 wt% of acetic acid was distilled out from the top side of the column, and cyclohexene oxide distilled to the top side of the column was a trace amount, and cyclohexene oxide 5
A solution containing 7.6 wt% of 19.4 g / hr was obtained, and acetic acid was not detected at all on the bottom side. The bottom yield of cyclohexene oxide was 93.0%.

[0026]

Comparative Example 1 A 40 mmφ 40-stage Oldershaw distillation column equipped with a thermosyphon type reboiler having a capacity of 100 ml was used to prepare cyclohexene oxide from the raw material reaction crude liquid obtained in Example 1 without using an azeotropic agent. Was tried. A reaction crude liquid obtained by epoxidizing cyclohexene with peracetic acid was charged at 182 g / hr on the 23rd stage from the kettle and continuously distilled at a reflux ratio of 3 while controlling the column top pressure to be 30 mmHg. As a result, acetic acid 2
Liquid containing 6.7 wt% 109.0 g / hr, liquid containing cyclohexene oxide 45.9 wt% from the bottom 5
5.5 g / hr was obtained. Separately, 17.5 g / hr of trap solution was obtained. The bottom yield of cyclohexene oxide was 77.5%.

In this comparative example, even if a column having a large number of plates, which is usually used in a laboratory, is used, the boiling point of acetic acid (11 at 760 mmHg) is obtained unless a compound that azeotropes with acetic acid is used as an azeotropic agent.
8 ℃) and boiling point of cyclohexene oxide (760mmH
It shows that acetic acid and cyclohexene oxide cannot be separated by distillation because they are close to each other (129 ° C. in g).

[0028]

According to the method of the present invention, a compound azeotropic with acetic acid is used to efficiently produce cyclohexene oxide, which has been difficult to separate by distillation by distillation because of its small boiling point difference with acetic acid and high reactivity with acetic acid. It became possible to separate by distillation.

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[Procedure amendment]

[Submission date] December 12, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of the Invention Method for separating acetic acid and cyclohexene oxide

[Claims]

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for separating acetic acid and cyclohexene oxide.

Cyclohexene oxide is an important compound as a raw material for dyes, pharmaceutical intermediates, and acaricides related to agricultural chemicals.

[0003]

2. Description of the Related Art Heretofore, as a method for producing cyclohexene oxide, (1) by reacting cyclohexene with hypochlorous acid,
After producing 2-chlorocyclohexanol, a method of treating with an alkali to epoxidize it (for example, BUL
L. SOC. CHIM (4), 37, 1454 (192
5) etc.) (2) A method of directly oxidizing with an organic peracid such as performic acid, peracetic acid or perpropionic acid (for example, Journal of Japan Society of Oil Chemistry, Vol. 36, No. 6, P.436-440 etc. )
(3) Hydrogen peroxide or hydroperoxide in the presence of a catalyst
A method of oxidizing with an oxide (for example, JP-A-49-124)
003, JP-A-52-211, and JP-A-62-23077.
8) (4) Liquid phase air oxidation in the presence of a catalyst such as a molybdenum complex (for example, JP-A-50-149645 and JP-A-52-3036) is known.

Among the above methods, the method (1) using hypochlorous acid is industrially carried out. However, since chlorine is present in the reaction system, there is a problem of equipment corrosion and a problem in products. There was a problem such as chlorine contamination. Moreover, since the reaction is carried out in two stages, the process is complicated for the simple reaction.

In the method (2) of directly oxidizing with an organic peracid, the reaction proceeds in a single stage and the reaction rate is very fast, and since no catalyst is used, the catalyst separation is carried out when industrially carried out. It has a great advantage such as no process required.

[0006] The inventors of the present invention, when carrying out the above-mentioned industrial processes, use a process-simple method of direct oxidation with an organic peracid, which is one of the organic peracids actually used industrially. , Peracetic acid, was found, conditions for obtaining cyclohexene oxide with a high reaction yield were found, and a patent has already been applied for.

[0007]

However, when the method for purifying cyclohexene oxide produced by the reaction was examined, it was found that the product cyclohexene oxide could not be obtained in good yield by the ordinary purification method by distillation.

[0008]

OBJECT OF THE INVENTION The object of the present invention is to carry out, when industrially carried out, the cyclohexene oxide produced by the process of direct oxidation with an organic peracid and the acetic acid present in the reaction crude liquid. It is to develop a method for efficient separation.

[0009]

That is, the present invention is
“Acetic acid and cyclohexene oxide are characterized by distilling and separating acetic acid and cyclohexene oxide in a high yield from a reaction crude liquid prepared by epoxidizing cyclohexene with peracetic acid to produce cyclohexene oxide, in the presence of a compound that is azeotropic with acetic acid. The method of separating oxides ". The method for distilling and separating acetic acid and cyclohexene oxide of the present invention in high yield will be described in detail below.

The present inventors have previously proposed and patented a method for efficiently producing cyclohexene oxide from cyclohexene by a one-step reaction. However, when the produced cyclohexene oxide is separated by an ordinary distillation method, it is epoxidized. Acetic acid contained in peracetic acid (760 m
mHg boiling point 118 ° C) and acetic acid by-produced after epoxidation reaction and generated cyclohexene oxide (760 mmH
Boiling point difference with boiling point 129 ° C in g (about 1 at 760 mmHg)
(1 ° C.) is small, the distillation yield is remarkably low. To make matters worse, the reactivity between acetic acid and cyclohexene oxide is high, so that the reaction is performed during the distillation and the distillation yield is further deteriorated (see Reaction Formula 1 below).

[0011]

[Chemical 1] The outline of the method for separating acetic acid and cyclohexene oxide is as follows. In the first distillation column, acetic acid is distilled as an azeotrope from the reaction crude liquid and the compound azeotropic with acetic acid at the top of the column, and cyclohexene oxide is charged in the reactor. Obtained as a mixture in liquid (or bottoms). And the pot liquid (or the bottom liquid) of the first tower
The cyclohexene oxide obtained as a mixture therein is purified after the second column. In the present invention, acetic acid is distilled as an azeotrope from the reaction crude liquid and the compound azeotropic with acetic acid in the first distillation column to the top of the column, and cyclohexene oxide is added to the kettle liquid (or bottom liquid). In particular, it relates to a method for separating acetic acid and cyclohexene oxide to obtain a mixture.

The contents of the invention will be described below step by step.

The amount of the compound azeotropically azeotroping with acetic acid for cyclohexene oxide in the crude reaction liquid should be at least 1 mol times the amount required for the azeotropic composition at the distillation pressure (the azeotropic composition varies depending on the pressure). It is used in an amount exceeding the above range, more preferably in a range of 1.1 to 3 times the molar amount.

If the amount is less than 1 mol times, acetic acid that is not distilled off azeotropically falls into the kettle having the highest temperature and reacts with cyclohexene oxide in (Reaction formula 1) to significantly deteriorate the cyclohexene oxide distillation yield. .. On the other hand, if the amount of the compound that is azeotropic with acetic acid is too large, it is not preferable because the heating vapor cost is increased during the azeotropic separation of acetic acid and the purification of cyclohexene oxide.

The compound for azeotroping with acetic acid may be charged at the same stage as the raw material reaction crude liquid or at a different stage, but more preferably it is azeotropic with acetic acid having a lower boiling point than acetic acid. In the case of a compound, it is preferable to charge the raw material reaction crude liquid in a stage lower than the stage. Toluene (760 mmHg at azeotropic temperature 11
0.6 ° C, azeotropic composition 28.1 wt% acetic acid / toluene 7
1.9 wt%), ethylbenzene (azeotropic temperature 114.65 ° C. at 760 mmHg, azeotropic composition 66 wt% acetic acid / ethylbenzene 34 wt%), o-xylene (760 mmH)
azeotropic temperature 116.0 ° C., azeotropic composition acetic acid 76 wt%
o-xylene 24 wt%), m-xylene (760 mm
Azeotropic temperature at Hg of 115.35 ° C, azeotropic composition of acetic acid 72.5
wt% · m-xylene 27.5 wt%), p-xylene (azeotropic temperature 115.25 ° C. at 760 mmHg, azeotropic composition acetic acid 72 wt% · p-xylene 28 wt%), n-heptane (azeotropic temperature 95 at 760 mmHg). C., azeotropic composition 17% by weight acetic acid / n-heptane 83% by weight), cyclohexene (azeotropic temperature 81.8 ° C. at 760 mmHg, azeotropic composition acetic acid 6.5% by weight, cyclohexene 93.5% by weight) and the like.

The distillation pressure is preferably as low as possible to reduce the temperature of the reboiler and in order to suppress side reactions, the distillation pressure is preferably as low as possible. However, it depends on the capacity of the condenser and the kind of the refrigerant, and is usually 10 to 100 mmHg. It is carried out at a top pressure, more preferably at a top pressure of 20 to 50 mmHg. If the distillation pressure is lowered too much, depending on the capacity of the condenser and the type of refrigerant, low-boiling substances (particularly low-boiling solvent of peracetic acid (such as ethyl acetate) and unreacted cyclohexene) cannot be collected, so the condenser- It is necessary to select a distillation pressure that is suitable for the capacity and the type of refrigerant.

The distillation system may be either a batch system or a continuous system, but since the temperature of the kettle including the inside of the distillation column is the highest, the residence time in the kettle is too long in the batch system, so that (reaction formula 1) It is preferable to carry out the continuous distillation because the side reaction of (3) easily occurs and the yield of cyclohexene oxide is lower than that in the continuous system.

Further, even in the case of the continuous system, the capacity of the thermosiphon type reboiler depends on the amount of the raw material crude liquid charged and the column diameter of the distillation column, but it is preferable to use as small a volume as possible. Therefore, in some cases, instead of the thermosiphon reboiler, an evaporator such as a thin film evaporator that can shorten the residence time of the liquid as much as possible may be used as the reboiler.

The cyclohexene oxide containing high-boiling substances from which acetic acid has been removed by azeotropic distillation and the compound azeotroping with excess acetic acid are further separated by batch distillation or continuous distillation to separate the compounds azeotropic with excess acetic acid and the high-boiling substances. , Pure cyclohexene oxide is obtained.

Specifically, in the case of batch distillation, a compound that is azeotropic with excess acetic acid is distilled off, and then cyclohexene oxide is distilled off to obtain a product. In the case of continuous distillation, a compound that is azeotropic with excess acetic acid is distilled off in the first column, and a bottom product is charged into the second column to distill cyclohexene oxide to obtain a product. The second column may be a batch distillation column or a continuous distillation column. In addition, even if cyclohexene oxide is obtained by performing batch distillation (or continuous distillation) by the above method after removing high boiling substances using a thin film evaporator or the like before batch distillation (or continuous distillation). good.

Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

[0022]

Example 1 1010 g of cyclohexene was placed in a 10 L glass round-bottomed flask equipped with a hot water bath, a stirrer, a thermometer, a condenser and a pump for continuously charging peracetic acid, and the mixture was immersed in the hot water bath while stirring with a stirrer. The temperature of the liquid in the reactor was raised to 30 ° C. After heating, peracetic acid 2
3830 g of an ethyl acetate solution containing 9.2 wt% and about 6 wt% of acetic acid was charged over 2 hours while keeping the liquid temperature in the reactor at 30 ° C, and further maintained at 30 ° C for 1 hour.

After completion of the reaction, the reaction crude liquid in the reactor was taken out and analyzed by gas chromatography.
As a result, the conversion of cyclohexene was 97.2%, and the yield of cyclohexene oxide based on cyclohexene was 9%.
At 4.2%, the selectivity of cyclohexene oxide based on cyclohexene was 96.9%.

The raw material reaction crude liquid produced by the above procedure was used in the following purification experiment. Since acetic acid and cyclohexene oxide react with each other during storage and change with time, the concentration of cyclohexene oxide in the raw material reaction crude liquid is I use a slightly lowered one.

[0025]

Example 2 Using a 40 mmφ 40-stage Oldershaw distillation column equipped with a thermosyphon type reboiler having a capacity of 100 ml, 66.5 g of a reaction crude liquid obtained by epoxidizing cyclohexene with peracetic acid at the 20th stage from the kettle was used. / Hr, and toluene at the 10th stage from the kettle was charged at 62.6 g / hr to control the column top pressure to 30 mmHg.
Continuous distillation was carried out with a reflux ratio of 1. As a result, 108.0 g / hr of a liquid containing 11.7 wt% of acetic acid was distilled out from the top side of the column, and cyclohexene oxide distilled to the top side of the column was a trace amount, and cyclohexene oxide 5
A solution containing 7.6 wt% of 19.4 g / hr was obtained, and acetic acid was not detected at all on the bottom side. The bottom yield of cyclohexene oxide was 93.0%.

[0026]

Comparative Example 1 A 40 mmφ 40-stage Oldershaw distillation column equipped with a thermosyphon type reboiler having a capacity of 100 ml was used to prepare cyclohexene oxide from the raw material reaction crude liquid obtained in Example 1 without using an azeotropic agent. Was tried. A reaction crude liquid obtained by epoxidizing cyclohexene with peracetic acid was charged at 182 g / hr on the 23rd stage from the kettle and continuously distilled at a reflux ratio of 3 while controlling the column top pressure to be 30 mmHg. As a result, acetic acid 2
Liquid containing 6.7 wt% 109.0 g / hr, liquid containing cyclohexene oxide 45.9 wt% from the bottom 5
5.5 g / hr was obtained. Separately, 17.5 g / hr of trap solution was obtained. The bottom yield of cyclohexene oxide was 77.5%.

In this comparative example, even if a column having a large number of plates which is usually used in the laboratory is used, the boiling point of acetic acid (11 at 760 mmHg is 11
8 ℃) and boiling point of cyclohexene oxide (760mmH
It shows that acetic acid and cyclohexene oxide cannot be separated by distillation because they are close to each other (129 ° C. in g).

[0028]

According to the method of the present invention, a compound azeotropic with acetic acid is used to efficiently produce cyclohexene oxide, which has been difficult to separate by distillation by distillation because of its small boiling point difference with acetic acid and high reactivity with acetic acid. It became possible to separate by distillation.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C07D 303/04

Claims (1)

[Claims] 1. An acetic acid and a cyclohexene oxide, characterized by distilling and separating acetic acid and cyclohexene oxide from a reaction crude liquid produced by epoxidizing cyclohexene with peracetic acid to produce cyclohexene oxide, in the presence of a compound azeotropic with acetic acid. Separation method.