JP2000256348A - Production of epsilon-caprolactone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing ε-caprolactone from cyclohexanone in high yield by using a hydrogen peroxide solution as oxidizing agent. SOLUTION: This method for producing ε-caprolactone from cyclohexanone by using a hydrogen peroxide solution is characterized by using as catalyst a rare earth element salt of a perfluoroalkyl-bearing compound represented by the formula [(RfSO2)nX]3M(Rf is a 1-8C perfluoroalkyl group; X is O, N or C; (n) is 1 when X is O, being 2 when X is N, or 3 when X is C; M is a rare earth element).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing ε-caprolactone from cyclohexanone and hydrogen peroxide.

[0002]

2. Description of the Related Art A method for synthesizing a carboquine compound by oxidizing cyclic ketones with hydrogen peroxide in the presence of various catalysts has been known. For example, Japanese Patent Publication No. 44-1
No. 0243 discloses a method of oxidizing ketones with hydrogen peroxide using an arsenic compound as a catalyst.
Japanese Patent Publication No. 1-35814 discloses a method in which a Friedel-craft catalyst such as antimony fluoride, tin fluoride or hydrogen fluoride is used, water is continuously removed during the reaction, and a cyclic ketone or the like is obtained in a substantially anhydrous state. Is reacted with hydrogen peroxide to produce a carboxy compound. JP-A-8-59
No. 649 discloses a method for producing caprolactone by reacting cyclohexanone with hydrogen peroxide while distilling and removing water using a zeolite catalyst treated with an organic halogen compound.

[0003] However, there have been problems that it is necessary to use a very toxic arsenic compound as a catalyst or to use a complicated reaction process such as removal of water to carry out the reaction under almost anhydrous conditions. In addition, these methods have a problem that a sufficient yield cannot be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing .epsilon.-caprolactone from cyclohexanone in high yield using aqueous hydrogen peroxide as an oxidizing agent.

[0005]

The present invention provides a method for producing ε-caprolactone from cyclohexanone and hydrogen peroxide, wherein a rare earth salt of a compound having a perfluoroalkyl group represented by the following formula is used as a catalyst. It is a method. [(RfSO ₂ ) _n X] ₃ M (wherein, Rf represents a perfluoroalkyl group having 1 to 8 carbon atoms. X is any of O, N and C elements, and n is Hour represents 1; N represents 2; and C represents 3.
M represents a rare earth element. Hereinafter, the present invention will be described in detail.

The catalyst used in the present invention is a rare earth salt of perfluoroalkylsulfonic acid ((RfSO ₃ ) ₃ M) or a rare earth salt of bis (perfluoroalkylsulfonyl) imide ([(RfSO ₂ ) ₂ N] ₃ M). And tris (perfluoroalkyl) methide rare earth salts ([(RfSO ₂ ) ₃
C] ₃ M) (wherein, Rf represents a perfluoroalkyl group having 1 to 8 carbon atoms, and M represents a rare earth element). Among them, rare earth salts of imides or methides having a large number of perfluoroalkyl groups are preferred.

The perfluoroalkyl group of the catalyst used in the present invention is a perfluoroalkyl group having 1 to 8 carbon atoms, and specific examples thereof include a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group and a nonafluorobutyl group. Group, undecafluoropentyl group, tridecafluorohexyl group, pentadecafluoroheptyl group, heptadecafluorooctyl group and the like. When n is 2 or 3, the perfluoroalkyl groups may be the same or different. Among them, those containing a perfluoroalkyl group having 2 to 6 carbon atoms are preferable.

The rare earth elements used in the present invention include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium,
Eurobium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Among them, scandium, yttrium, and ytterbium are preferred.

The method for synthesizing the catalyst used in the present invention is described below. The rare earth salt of perfluoroalkyl sulfonic acid, which is a catalyst used in the present invention, can be synthesized by reacting perfluoroalkyl sulfonic acid with a rare earth metal oxide or a rare earth metal carbonate. The rare earth salt of bis (perfluoroalkylsulfonyl) imide which is a catalyst used in the present invention is based on Japanese Patent Application Laid-Open No. 10-17541, and the precursor bis (perfluoroalkylsulfonyl) imide is perfluoroalkylsulfonylfuro. A bisperfluoroalkylsulfonylimide alkali metal salt is synthesized by reacting the alkali metal salt with an alkali metal-bis (trimethylsilyl) amide, and then the alkali metal salt is treated with concentrated sulfuric acid, or the aqueous solution of the alkali metal salt is converted to a hydrogen-based solution. Bis (perfluoroalkylsulfonyl) imide is obtained by ion exchange treatment using a strongly acidic ion exchange resin or the like. Next, the compound of the present invention can be synthesized by reacting the bis (perfluoroalkylsulfonyl) imide with a rare earth metal oxide or carbonate in an aqueous solvent.

The rare earth salt of tris (perfluoroalkyl) methide is based on US Pat. No. 5,554,664 and the like, and the precursor, tris (perfluoroalkylsulfonyl) methide, is obtained by reacting perfluorosulfonyl fluoride with methylmagnesium chloride. Then, the methide is synthesized, and then reacted with cesium carbonate to obtain a cesium salt, which is purified and then treated with concentrated sulfuric acid to obtain a purified methide. By reacting this with a rare earth carbonate or acetate, a rare earth salt of tris (perfluoroalkylsulfonyl) methide can be synthesized. Further, the methylene, which is an intermediate for the synthesis of methide, can be separated by purification by sublimation, and further reacted with methylmagnesium chloride and perfluorosulfonyl fluoride to produce the methide.

As the hydrogen peroxide used as the oxidizing agent, generally used 10 wt% to 60 wt% aqueous hydrogen peroxide can be used. The ratio of hydrogen peroxide used in the reaction is 2 to 0.1 mole ratio, preferably 1 to 0.2 mole ratio, relative to cyclohexanone. The reaction temperature is from 40 ° C to 140 ° C, preferably from 50 ° C to 120 ° C. The amount of the catalyst to be used is 0.1 to 20% by weight, preferably 0.5 to 5% by weight, based on cyclohexanone.

As a reaction system, a polar solvent such as alcohol, dioxane, acetonitrile, acetic acid or the like may be added to cyclohexanone and aqueous hydrogen peroxide as a solvent. Of course, the reaction can be carried out without using a solvent. As a form of use of the catalyst, a method using an ordinary solid catalyst such as a slurry suspension method or a fixed bed flow method as a molded catalyst can be applied.

The catalyst used in the present invention has little effect on the inhibition of the catalytic activity by water, and can be used for the reaction even with a relatively thin aqueous hydrogen peroxide solution. The presence of water in the reaction system is caused by the aldol condensation of cyclohexanone. It also has the effect of suppressing the generation of by-products. According to the method of the present invention, ε is obtained from cyclohexanone with high yield and high hydrogen peroxide selectivity.
-Caprolactone can be produced.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples. The analysis of the oxidation reaction was performed by GC manufactured by Shimadzu Corporation.
The yield of the oxidation product was measured by using a 9A-type gas chromatography, and the yield was shown based on the starting material cyclohexanone. The reaction rate of hydrogen peroxide was determined by an iodometry method, and the ratio of the reduced hydrogen peroxide used for the production of ε-caprolactone was defined as the effective utilization rate.

[0015]

Example 1 Synthesis Example of Rare Earth Salt of Perfluoroalkanesulfonylimide Synthesis of N-trimethylsilyl perfluorobutanesulfonylamide Na salt (A) After replacing with nitrogen in a 300 ml beaker with a dropping funnel, perfluorobutanesulfonyl fluoride 36.2 g (1
20 mmol), 60 ml of a 1 mol solution of bistrimethylsilylamide sodium salt in tetrahydrofuran was added dropwise over 30 minutes under stirring and ice cooling, and the reaction was allowed to proceed under ice cooling for 3 hours and then at room temperature overnight. Non-reacted nonafluorobutanesulfonyl fluoride and THF from the reaction solution
Solvent etc. under reduced pressure (60 ° C, 30mmHg, then 1mmH
g) to give crude N-trimethylsilyl perfluorobutanesulfonylamide sodium salt (A). 2. Synthesis of bisperfluorobutanesulfonylimide Na salt (B) Next, 26 g (90 mmol) of A and perfluorobutanesulfonyl fluoride and 35 ml of dioxane were charged into a 200 ml autoclave (with a Teflon inner cylinder) under a nitrogen atmosphere using a dry box. 120 with stirring
The reaction was performed at 8 ° C. for 8 hours. Unreacted perfluorobutanesulfonyl fluoride, dioxane solvent and the like are removed from this reaction solution under reduced pressure (80 ° C., 40 mmHg, then 1 mmHg).
This was removed to obtain 25 g of a light brown solid (B).

The infrared absorption spectrum of the solid (B) is 135
SO around 8cm ^-1 , 1140cm ^-1 , 1083cm ^-1
An absorption peak due to _two groups was observed. 3. Conversion to bisperfluorobutanesulfonylimide (C) 10 g of this solid B was dissolved in 500 ml of water, and the solution was added to a strongly acidic ion exchange resin (Amberlite IR-120B) 20
The solution was passed through an ion-exchange column (20 mmφ glass column) filled with the solution to obtain a crude imide aqueous solution. P of this effluent
H showed 2.4. This aqueous solution was water-bathed at 80 ° C. and 160 mmHg using a rotary evaporator.
The water was distilled off under reduced pressure of 60 mmHg to obtain 8.6 g of a light brown solid (C). 0.1 g of (C) was dissolved in water and titrated with a 0.1 N aqueous solution of caustic soda to find that the strong acid component was 1.7 × 10 ⁻¹ meq. 4. High Purity The solid C is treated with a vacuum dryer at 60 ° C. and 1 mmHg for 1 hour, and then under high vacuum (105 ° C., 6 × 10 ^-2 m
mHg) to obtain white crystals.

The infrared absorption spectrum of this crystal shows 135
SO around 8cm ^-1 , 1140cm ^-1 , 1083cm ^-1
An absorption peak due to _two groups was observed. 5. Synthesis of ytterbium salt of imide 5 g of bisperfluorobutanesulfonylimide synthesized by the above method was mixed with 20 ml of distilled water and acetonitrile 80
0.63 g of ytterbium oxide was added to the solution dissolved in ml of the mixed solvent, and reacted at 60 ° C. for 1 hour with stirring. Then, unreacted ytterbium oxide was removed by filtration, and the solvent was removed from the filtrate using a rotary evaporator.
Vacuum drying was performed at 0 ° C. and 1 mmHg for 1 hour to obtain 4.6 g of the ytterbium salt of the imide as a white powder. This compound is hygroscopic, but has low solubility in water. Synthesized tris [bis (perfluorobutanesulfonyl)
[Imido] ytterbium has an infrared absorption spectrum of 114.
To ₂ groups SO to 0 cm ^-1 vicinity, near 1085 cm ^-1 C-
An absorption peak attributed to the F group was observed. Composition analysis by fluorescent X-ray analysis (the values in parentheses are theoretical values): F /
S / Yb = 57 / 5.6 / 1 atomic ratio (54/6/1)

[0018]

Example 2 Synthesis Example of Rare Earth Salt of Perfluoroalkanesulfonylmethide Synthesis of perfluorobutanesulfonyl methide 1.1 Synthesis of (C ₄ F ₉ SO ₂ ) ₂ CH ₂ After replacing the nitrogen in a 500 ml beaker with a dropping funnel, a THF solution of methylmagnesium chloride (3 mol)
173 ml), 143 g of perfluorobutanesulfonyl fluoride was slowly added dropwise over 5 hours under stirring and cooling with ice, then the temperature was raised to 65 ° C., and the reaction was continued for 45 hours. Then, the reaction solution was dried up (70 ° C., 32 mmH
g) and vacuum drying (70 ° C., 1 mmHg) to obtain a brown solid.

Then, 35% sulfuric acid was added over 30 minutes under ice-cooling and stirring, and the mixture was reacted at room temperature for 16 hours. Then, extraction was carried out using isopropyl ether (225 ml × 2), dried up (40 ° C., 32 mmHg), and dried under vacuum (40 ° C., 8 hours) to obtain 70 g of a brownish moist solid. This solid is purified by sublimation (75 ° C, 5 mmH
g) to give 34 g of (C ₄ F ₉ SO ₂ ) ₂ CH
₂ (A) was obtained. In the infrared absorption spectrum of this sample, C-H stretching absorption was observed at 2999 cm ^-1 and 2930 cm ^-1 .

1.2 Synthesis of (C ₄ F ₉ SO ₂ ) ₃ CH A sample (A) (30 g) was dissolved in THF (120 ml), and the mixture was cooled with ice and stirred with THF of methyl magnesium chloride.
120 ml of the solution (3 mol solution) is dropped in 10 minutes,
Then, the reaction was carried out at room temperature for 24 hours. Subsequently, 31.2 g of perfluorobutanesulfonyl fluoride was added dropwise over 5 minutes, and after 1 hour at room temperature, the mixture was transferred to an autoclave.
The mixture was reacted at 24 ° C. for 24 hours, and the reaction solution was taken out, dried up (60 ° C., 28 mmHg), and dried in vacuum (60 ° C., 8 hours) to obtain 56.4 g of powder. Then 35% sulfuric acid 14
This powder was added to 0 ml, treated at room temperature for 24 hours, extracted with 100 ml of isopropyl ether, dried up (40 ° C., 28 mmHg), and vacuum dried (40 ml).
C., 5 hours) to obtain 40 g of crude perfluorobutanesulfonyl methide. For purification, this was dissolved in methylene chloride, a 50% cesium carbonate aqueous solution was added to precipitate as a cesium salt, washed with water, washed with toluene, washed with methylene chloride, and vacuum-dried (120 ° C., 5 hours) to obtain 44 g of an off-white powder. Obtained. Next, similarly treated with 35% sulfuric acid, extracted, dried up, vacuum dried, and then sublimated (75 ° C.-2 mmH
g, then 110 ° C.-2 mmHg), 44% recovery of raw material (A), 15 g (41%) of purified methide, (B)
I got

The synthesized perfluorobutanesulfonyl methide (B) was converted into an ethanol-water (2/1) solution, and the solution was added in a concentration of 0.1%.
Neutralization titration of 01N NaOH aqueous solution resulted in 860
A value of g / eq was obtained (theoretical value is 862). 2. Synthesis of Rare Earth Salt of Methide 3.26 g of perfluorobutanesulfonylmethide was dissolved in a mixed solution of acetonitrile-water (1/1), and 0.43 g of ytterbium carbonate dihydrate was added, followed by stirring at room temperature for 1 hour, and then at 60 ° C. The reaction was performed for 1 hour. After removing unreacted ytterbium carbonate by filtration, dry-up (70
℃, 25mmHg), vacuum drying (70 ℃, 6 hours)
3.13 g of the ytterbium salt of the methide were obtained.

The infrared absorption spectrum of the synthesized tris (perfluorobutanesulfonyl) ytterbium salts methide to ₂ groups SO near 1140cm ^-1, 1031cm ^-1
An absorption peak attributable to the CF group was observed in the vicinity. As a result of the composition analysis, the Yb / C ratio was 0.364 (theoretical 0.37).
1).

[0023]

Example 3 9.8 g of cyclohexanone, 0.5 g of ytterbium salt of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.5 g of hydrogen peroxide (concentration) were placed in a 50 ml three-necked flask equipped with a condenser and a stirrer. (30 wt%) was added, and the mixture was placed in an oil bath heated to a predetermined temperature of 60 ° C. to perform an oxidation reaction. The yield of ε-caprolactone after a reaction time of 2 hours was 11 mol%. The effective utilization rate of hydrogen peroxide was 95%.

[0024]

Example 4 A caprolactonization reaction of cyclohexanone was carried out in the same manner as in Example 3 except that the ytterbium salt of bis (trifluoromethanesulfonyl) imide obtained as in Example 1 was used as a catalyst. As a result, the yield of ε-caprolactone after 2 hours of the reaction time was 14 mol%. The effective utilization rate of hydrogen peroxide was 98%.

[0025]

Example 5 An oxidation reaction was carried out at 40 ° C. in the same manner as in Example 3, except that a scandium salt of trifluoromethanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as a catalyst. As a result, the yield of ε-caprolactone at the second reaction time was 1
It was 2 mol%. The effective utilization rate of hydrogen peroxide was 98%.

[0026]

Example 6 As in Example 3, except that the catalyst used was the ytterbium salt of bis (perfluorobutanesulfonyl) imide obtained in Example 1 and the amount of aqueous hydrogen peroxide was 11 g.
The oxidation reaction was carried out at 60 ° C. As a result, the yield of ε-caprolactone after 2 hours of the reaction time was 17 mol%. The effective utilization rate of hydrogen peroxide was 68%.

[0027]

Example 7 As in Example 3, except that the catalyst used was the yttrium salt of bis (perfluorooctanesulfonyl) imide obtained in the same manner as in Example 1, and the amount of hydrogen peroxide solution was 11 g. The oxidation reaction was performed under the condition of ° C. As a result, the yield of ε-caprolactone at the second reaction time was 2
It was 0 mol%. The effective utilization rate of hydrogen peroxide was 75%.

[0028]

Example 8 As in Example 3, but using the ytterbium salt of bis (trifluoromethanesulfonyl) imide obtained as in Example 1 as a catalyst, the amount of hydrogen peroxide solution (concentration: 10 wt%) was adjusted to 16.5 g. The caprolactonization reaction of cyclohexanone was carried out at 60 ° C. As a result, the yield of ε-caprolactone at a reaction time of 2 hours was 10 mol%. The effective utilization rate of hydrogen peroxide was 78%.

[0029]

Example 9 In the same manner as in Example 3, except that the ytterbium salt of tris (perfluorobutanesulfonyl) methide obtained in Example 2 was used as a catalyst, caprolactonization of cyclohexanone was carried out at 40 ° C. As a result, the yield of ε-caprolactone at the second reaction time was 13 mol%.
Met. The effective utilization rate of hydrogen peroxide was 98%.

[0030]

Example 10 A caprolactonization reaction of cyclohexanone was carried out at 40 ° C. using the scandium salt of tris (perfluorobutanesulfonyl) methide obtained in the same manner as in Example 2 except that the catalyst was the same as in Example 3. Was.
As a result, the yield of ε-caprolactone after 2 hours of the reaction time was 16 mol%. Effective use rate of hydrogen peroxide is 99%
Met.

[0031]

Example 11 In the same manner as in Example 3, except that 100 ml of acetonitrile was added as a solvent, cyclohexanone was subjected to caprolactonation at 40 ° C. result,
The yield of ε-caprolactone after a reaction time of 2 hours was 11 mol%. The effective utilization rate of hydrogen peroxide was 98%.

[0032]

Comparative Example 1 As in Example 3, except that a proton type ZSM-5 zeolite (silica / alumina ratio 4
2) A caprolactonization reaction of cyclohexanone was performed using 2 g. As a result, the yield of ε-caprolactone in a 2-hour reaction was 5.5 mol%. The effective utilization rate of hydrogen peroxide was 45%.

[0033]

COMPARATIVE EXAMPLE 2 As in Example 3, except that the amount of hydrogen peroxide solution was 11 g, anhydrous aluminum chloride (manufactured by Wako Pure Chemical Industries, Ltd.) 4.4 g as a catalyst, the reaction temperature was 60 ° C., and cyclohexanone was used. Was subjected to a caprolactonization reaction. As a result, the yield of ε-caprolactone in the 4-hour reaction was 5.5%. The effective utilization rate of hydrogen peroxide was 42%.

[0034]

Comparative Example 3 As in Example 3, except that the amount of hydrogen peroxide solution was 11 g, the proton type ZSM-5 zeolite (silica / alumina ratio: 36) was used as a catalyst, and the reaction temperature was 60 ° C. A lactonization reaction of clohexanone was performed. Result The yield of ε-caprolactone in the 2-hour reaction was 8.
It was 5 mol%. The effective utilization rate of hydrogen peroxide was 38%.

[0035]

Comparative Example 4 As in Example 3, except that 0.5 g of tin chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a catalyst at 40 ° C.
The caprolactonization reaction of cyclohexanone was carried out. As a result, the yield of ε-caprolactone in the 2-hour reaction was 8 mol%. The effective utilization rate of hydrogen peroxide was 65%.

[0036]

According to the method of the present invention, hydrogen peroxide solution is used as an oxidizing agent to easily convert cyclohexanone into ε in high yield.
-Caprolactone can be produced.

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Claims (1)

[Claims] 1. An ε-cyclohexanone and hydrogen peroxide
A method for producing caprolactone, wherein a rare earth salt of a compound having a perfluoroalkyl group represented by the following formula is used as a catalyst. [(RfSO ₂ ) _n X] ₃ M (wherein, Rf represents a perfluoroalkyl group having 1 to 8 carbon atoms. X is any of O, N and C elements, and n is Hour indicates 1; N indicates 2; C indicates 3.
M represents a rare earth element. )