CN103450144A - Method for preparing epsilon-caprolactone through biomimetic catalysis of cyclohexanone oxidation - Google Patents

Abstract

The invention discloses a method for preparing epsilon-caprolactone through biomimetic catalysis of cyclohexanone oxidation. In the method, cyclohexanone is used as a raw material, oxygen is used as an oxidizing agent, a metal phthalocyanine or metalloporphyrin compound is used as a catalyst, the reaction temperature is controlled at 25-120 DEG C, and the epsilon-caprolactone is obtained through a catalytic reaction under normal-pressure conditions. The method disclosed by the invention has the advantages of simple technology, mild conditions, high selectivity, safety, low cost and the like.

Description

A method for preparing ε-caprolactone by biomimetic catalytic oxidation of cyclohexanone

technical field

The invention relates to a method for preparing ε-caprolactone, in particular to a method for preparing ε-caprolactone by biomimetic catalysis of cyclohexanone oxidation.

Background technique

ε-caprolactone is an important polymer monomer. As a new type of polyester monomer, it is widely used in the synthesis of various polycaprolactone (PCL) and blended modified resins, and as a It is an excellent organic solvent and an important organic synthesis intermediate. It shows good solubility to some insoluble resins and can react with various compounds to prepare fine chemicals with unique properties. At present, the method of industrial production of ε-caprolactone is mainly realized by the Baeyer-Villiger oxidation reaction. The oxidant used is usually an organic peracid such as peracetic acid. There are problems such as poor safety and high energy consumption during use, which makes the process application is limited.

The preparation of ε-caprolactone by using convenient, easy-to-obtain, safe and environment-friendly molecular oxygen/air as the oxidant has become a research trend, among which biomimetic catalysts such as metalloporphyrins or metallophthalocyanines can activate oxygen under mild conditions. The oxidation reaction has the advantages of safety, greenness, high efficiency and high selectivity. Chinese patent ZL 101205225A reports a method for producing lactones by metalloporphyrin biomimetic catalyzed oxidation of ketones. This method involves the process of preparing ε-caprolactone by oxidation of cyclohexanone B-V, but there is a large amount of additives (the raw material 15 times), harsh conditions and other issues, so the industrial application of this method is limited. Patent ZL201110298626.1 reported a method for the preparation of ε-caprolactone through the oxygen oxidation of cyclohexanone catalyzed by a metalloporphyrin with a simple structure. However, in this method, metal oxides or molecular sieves are used as cocatalysts, and the catalytic system is complicated and separation is difficult. shortcoming.

Therefore, the development of a preparation process of ε-caprolactone using cyclohexanone as raw material, oxygen as oxidant, mild conditions, simple process and high selectivity will have a very important application prospect.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a method for preparing ε-caprolactone by biomimetic catalyzing the oxidation of cyclohexanone.

For realizing the purpose of the present invention, the technical scheme adopted is: take cyclohexanone as raw material, take oxygen as oxygenant, add organic solvent and auxiliary agent benzaldehyde, with the metal phthalocyanine of general formula (I) structure, general formula The mononuclear metalloporphyrin of (II) structure, the oxometalloporphyrin of general formula (III) structure, the μ-oxygen-binuclear metalloporphyrin of general formula (IV) structure are used as catalyzer, and control is 25～120 at reaction temperature ℃, under the condition of normal pressure, the catalytic reaction is carried out to obtain ε-caprolactone, wherein the concentration of the catalyst is 0.1-100ppm, and the molar ratio of the auxiliary agent benzaldehyde to the raw material cyclohexanone is 0.01-2,

M in general formula (I) ₁ is transition metal atom Mg, Al, Cr, Mn, Fe, Co, Ni, Cu or Zn, R is hydrogen or carboxyl or sulfonic acid group; M in general formula (II) ₂ is metal atom Cr, Mn, Fe, Co, Ni, Cu, Zn, Rh, Ru or Sn, X is halogen or hydrogen, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all selected from hydrogen, halogen, Nitro, alkyl, alkoxy, hydroxyl, carboxyl, mercapto or sulfonic acid group, ligand X ₁ is chlorine or imidazole or pyridine; M in general formula (III) ₃ is metal atom Mo, Fe, Mn, V, Ti, Ru or Rh, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all selected from hydrogen, halogen, nitro, alkyl, alkoxy, hydroxyl, carboxyl, mercapto or sulfonic acid; M in formula (IV) is metal atom Al, Fe, Co, Mn, _Zn , Ru or Rh, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all selected from hydrogen, halogen, nitro, alkane group, alkoxy group, hydroxyl group, carboxyl group, mercapto group or sulfonic acid group.

In the method for preparing ε-caprolactone by the above-mentioned biomimetic catalytic cyclohexanone oxidation, the preferred catalyst consumption is 1-50ppm, the preferred auxiliary agent benzaldehyde and raw material cyclohexanone molar ratio is 0.5～2, and the preferred reaction temperature is 30-100°C.

In the method for preparing ε-caprolactone by biomimetic catalytic cyclohexanone oxidation, the solvent is 1,2-dichloroethane, 1,4-dioxane, trifluorotoluene, n-butyl acetate, One or more of sec-butyl acetate, acetonitrile and ethyl acetate are mixed.

The invention first synthesizes metal phthalocyanine and metal porphyrin biomimetic catalysts, dissolves the catalysts uniformly in a solvent, and uses benzaldehyde as an auxiliary agent to catalyze the oxidation of cyclohexanone to generate ε-caprolactone in the presence of oxygen. On the one hand, the biomimetic catalyst activates molecular oxygen, and on the other hand, it also promotes the initiation of free radicals. After a series of free radicals grow, a high-priced active substance with strong oxidation properties is formed, which is easy to attack the carbonyl of cyclohexanone, which is beneficial to ε- Production of caprolactone.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention adopts oxygen as an oxidizing agent, avoiding the safety problem caused by using peracid.

2. The present invention uses a metal porphyrin compound or a metal phthalocyanine with a structure similar to a biological enzyme as a catalyst, and the amount of catalyst and auxiliary agent is small.

3. The present invention has simple operation process, mild conditions, low economic cost, green safety and good industrial application prospect.

Detailed ways

The present invention will be further described below in conjunction with the examples, but the protection scope of the present invention is not limited to the scope indicated by the examples.

The reagents used in the examples are commercially available analytical reagents.

The biomimetic catalysts such as metal phthalocyanine, metal porphyrin used in the embodiment are according to prior art (Alder AD, et al.J.Org.Chem.1967,32,476; Wang LZ et al.Org.Process Res.Dev.2006 , 10,757) prepared by the method described.

Example 1

In 5mL containing 50ppm of sec-butyl acetate solution with metal phthalocyanine (M ₁ =Al, R=H) of general formula (I), add 1mmol of cyclohexanone and 2mmol of benzaldehyde, feed oxygen, at temperature The reaction was stirred and reacted at 70°C for 6 hours, and the conversion rate of cyclohexanone was 92% and the yield of ε-caprolactone was 92% through quantitative detection and analysis by gas chromatography internal standard method.

Example 2

In 5 mL of trifluorotoluene solution containing 0.1 ppm of metal phthalocyanine (M ₁ =Mg, R = COOH) with general formula (I), add 1 mmol of cyclohexanone and 1 mmol of benzaldehyde, feed oxygen, at temperature The reaction was stirred and reacted at 100°C for 2 hours, and the conversion rate of cyclohexanone was 80% and the yield of ε-caprolactone was 80% through quantitative detection and analysis by gas chromatography internal standard method.

Example 3

In 5 mL of trifluorotoluene solution containing 10 ppm metal phthalocyanine (M ₁ =Zn, R ₁ =COOH, R ₂ , R ₃ , R ₄ , R ₅ =H) with general formula (I), add 1 mmol of cyclo Hexanone and 0.1mmol of benzaldehyde were passed into oxygen, and the temperature was stirred at 100°C for 8 hours. Through the quantitative detection and analysis of gas chromatography internal standard method, the conversion rate of cyclohexanone was 83%, and the conversion rate of ε-caprolactone The yield was 83%.

Example 4

_{In 5 mL of 1,2 _ _} -In the dichloroethane solution, add 1mmol of cyclohexanone and 0.5mmol of benzaldehyde, feed oxygen, and stir and react at a temperature of 25°C for 12 hours, and quantitatively detect and analyze the cyclohexanone through gas chromatography internal standard method. The conversion rate was 89%, and the yield of ε-caprolactone was 88%.

Example 5

Trifluorotoluene containing 50 ppm of metalloporphyrins of general formula (II) (M ₂ =Rh, R ₁ , R ₂ , R ₄ , R ₅ =H, R ₃ =SO ₃ H, X ₁ is imidazole) in 5 mL In the solution, add 1mmol of cyclohexanone and 1mmol of benzaldehyde, pass through oxygen, and stir and react at a temperature of 120°C for 2 hours. Quantitative detection and analysis by gas chromatography internal standard method shows that the conversion rate of cyclohexanone is 93%. The yield of ε-caprolactone was 93%.

Example 6

100 ppm metalloporphyrins with general formula (II) in 5 mL (M ₂ =Ru, R ₁ =C ₂ H ₅ , R ₃ =NO ₂ , R ₂ , R ₄ , R ₅ =H, X ₁ =Cl) Add 2mmol of cyclohexanone and 1mmol of benzaldehyde to the n-butyl acetate solution, feed oxygen, stir and react at a temperature of 80°C for 4 hours, and quantitatively detect and analyze through gas chromatography internal standard method, the conversion of cyclohexanone The yield was 95%, and the yield of ε-caprolactone was 95%.

Example 7

_{Add 1 mmol of cyclohexane _ _} Ketone and 1.5mmol of benzaldehyde were passed into oxygen, and the temperature was 60°C and the reaction was stirred for 5 hours. After quantitative detection and analysis by gas chromatography internal standard method, the conversion rate of cyclohexanone was 97%, and the recovery of ε-caprolactone The rate is 97%.

Example 8

In 5 mL of ethyl acetate solution containing 30 ppm of metalloporphyrins of general formula (III) (M ₃ =V, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ =CH ₃ ,), add 1 mmol of cyclo Hexanone and 2mmol of benzaldehyde, fed oxygen, stirred and reacted at a temperature of 30°C for 6 hours, quantitatively detected and analyzed by gas chromatography internal standard method, the conversion rate of cyclohexanone was 86%, and the recovery of ε-caprolactone The rate is 86%.

Example 9

In 5 mL of 1,4-dioxane solution containing 10 ppm of a metalloporphyrin of general formula (III) (M ₃ =Ru, R ₁ , R ₂ , R ₃ , R ₄ =H, R ₅ =COOH) , add 1mmol of cyclohexanone and 1mmol of benzaldehyde, feed oxygen, stir and react at a temperature of 50°C for 7 hours, quantitatively detect and analyze by gas chromatography internal standard method, the conversion rate of cyclohexanone is 93%, ε- The yield of caprolactone was 93%.

Example 10

In 5 mL of 1,2-dichloroethane solution containing 40 ppm metalloporphyrins of general formula (IV) (M ₄ =Al, R ₁ , R ₂ , R ₄ , R ₅ =H, R ₃ =CH ₃ ) , add 1mmol of cyclohexanone and 1mmol of benzaldehyde, feed oxygen, stir and react at a temperature of 60°C for 8 hours, and quantitatively detect and analyze through gas chromatography internal standard method, the conversion rate of cyclohexanone is 90%, ε - The yield of caprolactone is 90%.

Example 11

_{Add 2mmol _ _ _ _} Cyclohexanone and 1mmol of benzaldehyde were passed into oxygen, and the temperature was 100°C for a stirring reaction for 5 hours. Through gas chromatography internal standard method quantitative detection and analysis, the conversion rate of cyclohexanone was 95%, and the conversion rate of ε-caprolactone was 95%. The yield is 95%.

Example 12

_{Add _ _ _ _ _ _} 1mmol of cyclohexanone and 1mmol of benzaldehyde were passed into oxygen, and the temperature was 90°C and the reaction was stirred for 6 hours. Through quantitative detection and analysis by gas chromatography internal standard method, the conversion rate of cyclohexanone was 92%. The yield of ester was 92%.

Claims (5)

1. a bionic catalysis oxidizing cyclohexanone prepares the method for 6-caprolactone, it is characterized in that take that pimelinketone is as raw material, take oxygen as oxygenant, add organic solvent and auxiliary agent phenyl aldehyde, to there is the metal phthalocyanine of general formula (I) structure, the monokaryon metalloporphyrin of general formula (II) structure, the oxo metalloporphyrin of general formula (III) structure, μ-the oxygen of general formula (IV) structure-dinuclear metalloporphyrin is made catalyzer, being controlled at temperature of reaction is 25～120 ℃, carry out catalyzed reaction under the condition of normal pressure and obtain 6-caprolactone, wherein the concentration of catalyzer is 0.1-100ppm, the mol ratio of auxiliary agent phenyl aldehyde and raw material pimelinketone is 0.01～2,

M in general formula (I) ₁be transition metal atoms Mg, Al, Cr, Mn, Fe, Co, Ni, Cu or Zn, R is hydrogen or carboxyl or sulfonic group; M in general formula (II) ₂be atoms metal Cr, Mn, Fe, Co, Ni, Cu, Zn, Rh, Ru or Sn, X is halogen or hydrogen, R ₁, R ₂, R ₃, R ₄and R ₅all be selected from hydrogen, halogen, nitro, alkyl, alkoxyl group, hydroxyl, carboxyl, sulfydryl or sulfonic group, dentate X ₁chlorine or imidazoles or pyridine; M in general formula (III) ₃atoms metal Mo, Fe, Mn, V, Ti, Ru or Rh, R ₁, R ₂, R ₃, R ₄and R ₅all be selected from hydrogen, halogen, nitro, alkyl, alkoxyl group, hydroxyl, carboxyl, sulfydryl or sulfonic group; M in general formula (IV) ₄atoms metal Al, Fe, Co, Mn, Zn, Ru or Rh, R ₁, R ₂, R ₃, R ₄and R ₅all be selected from hydrogen, halogen, nitro, alkyl, alkoxyl group, hydroxyl, carboxyl, sulfydryl or sulfonic group.

2. method according to claim 1, is characterized in that described catalyst levels is 1-50ppm.

3. method according to claim 1, the mol ratio that it is characterized in that auxiliary agent phenyl aldehyde and raw material pimelinketone is 0.5～2.

4. method according to claim 1, the temperature that it is characterized in that catalyzed reaction is 30-100 ℃.

5. method according to claim 1, is characterized in that described solvent is one or more mixing in 1,2-ethylene dichloride, Isosorbide-5-Nitrae-dioxane, phenylfluoroform, n-butyl acetate, sec-butyl acetate, acetonitrile, ethyl acetate.