阅读说明：本技术 一种ε-己内酯的制备方法 (Preparation method of epsilon-caprolactone ) 是由 杨为民 李相呈 王振东 刘闯 于 2019-10-25 设计创作，主要内容包括：本发明提供一种ε-己内酯的制备方法,包括：在SCM-14分子筛和任选地有机溶剂的存在下,使环己酮和含有过氧化氢的溶液接触,生成ε-己内酯。通过采用SCM-14分子筛为催化剂,在高投料比条件下,环己酮转化率和产物己内酯选择性均非常高,且SCM-14分子筛具有较高的稳定性。(The invention provides a preparation method of epsilon-caprolactone, which comprises the following steps: cyclohexanone and a solution containing hydrogen peroxide are contacted in the presence of SCM-14 molecular sieve and optionally an organic solvent to produce epsilon-caprolactone. By adopting the SCM-14 molecular sieve as the catalyst, the cyclohexanone conversion rate and the caprolactone selectivity are both very high under the condition of high feed ratio, and the SCM-14 molecular sieve has higher stability.)

1. A method for producing epsilon-caprolactone, comprising: cyclohexanone and a solution containing hydrogen peroxide are contacted in the presence of SCM-14 molecular sieve and optionally an organic solvent to produce epsilon-caprolactone.

2. The preparation method according to claim 1, wherein the mass ratio of the SCM-14 molecular sieve to the cyclohexanone is (0.1-10): 1, preferably (0.125-2): 1.

3. The production method according to claim 1 or 2, wherein the mass ratio of the cyclohexanone to the hydrogen peroxide is 1 (0.3 to 1.5).

4. The process according to any one of claims 1 to 3, characterized in that the SCM-14 molecular sieve (in particular in its as-synthesized or its calcined form) has an X-ray diffraction pattern substantially as shown in Table A-1 or Table A-2 below,

TABLE A-1

(a) ± 0.3 °, (b) varies with 2 θ,

TABLE A-2

(a)＝±0.3°。

5. The production method according to any one of claims 1 to 4, characterized in that the organic solvent is at least one selected from the group consisting of nitrile compounds, ether compounds and alcohol compounds, preferably at least one selected from the group consisting of nitrile compounds.

6. The production method according to claim 5, characterized in that the nitrile compound includes acetonitrile and propionitrile; and/or the ether compounds include tetrahydrofuran, 1, 4-dioxane and diisopropyl ether; and/or the alcohol compound comprises C₁-C₃Alcohols, preferably methanol, ethanol, n-propanol and isopropanol.

7. The production method according to claim 5, wherein the mass ratio of the organic solvent to the cyclohexanone is (0-10): 1, preferably (2-6): 1.

8. The preparation method according to any one of claims 1 to 7, wherein the mass fraction of the hydrogen peroxide is 20 to 80 wt%, preferably 30 to 70 wt%, more preferably 40 to 70 wt%, and more preferably 50 to 70 wt%.

9. The method of any one of claims 1-8, wherein the contacting conditions comprise: the temperature is 50-110 ℃, and the time is 2-8 h.

10. The method of claim 9, wherein the contacting conditions comprise: the temperature is 60-90 ℃ and the time is 4-6 h.

Technical Field

The invention relates to the technical field of chemical industry, in particular to a preparation method of epsilon-caprolactone.

Background

Epsilon-caprolactone (caprolactone for short) is a nontoxic novel polyester monomer and has irreplaceable effects in the aspects of synthesis and modification of high polymer materials, a polymerization product is biodegradable polycaprolactone, and the glossiness, transparency, biodegradability, anti-adhesion property and the like of the material can be improved by copolymerizing the caprolactone with various monomers or blending the caprolactone with other resins. Caprolactone is also an excellent organic solvent and an important organic synthesis intermediate, shows good solubility for some insoluble resins, and can react with various compounds to prepare fine chemicals with unique properties. In recent years, with the increasing use of caprolactone, the market demand has increased, and studies on caprolactone have been increasingly focused. The preparation method of caprolactone mainly comprises a Baeyer-Villiger oxidation method of cyclohexanone; 6-hydroxy caproic acid intramolecular condensation method; 1, 6-hexanediol catalytic dehydrogenation, and the like. Of these, the Baeyer-Villiger oxidation of cyclohexanone is the most efficient process.

The oxidation method is mainly classified into a peroxy acid oxidation method, a molecular oxygen oxidation method (oxygen and air), a biological oxidation method, and the like, depending on the oxidizing agent used in the reaction. The technology for synthesizing caprolactone by oxidizing cyclohexanone by organic peroxy acid is mature and is applied to industrial production on a large scale, but the organic peroxy acid has the following defects: firstly, a large amount of wastes such as organic carboxylate and the like are generated after the reaction of the organic peroxyacid, and the wastes are easily mixed with cyclohexanone, caprolactone and the like, so that the separation difficulty and cost are increased; secondly, the organic peroxy acid is expensive, and the use safety is low. Molecular oxygen (oxygen, air, etc.) has long received attention as a convenient, readily available, safe oxidant. However, since the oxidation capability of molecular oxygen is weak, satisfactory results cannot be obtained by directly oxidizing cyclohexanone by molecular oxygen, and an aldehyde co-oxidant and a proper catalyst are usually added in the reaction process to play a role in oxidizing cyclohexanone, thereby increasing the production and product separation costs.

Compared with the oxidation mode of peroxy acid and molecular oxygen, the main byproduct of the oxidation reaction of cyclohexanone by using hydrogen peroxide as an oxidant is H₂O, does not pollute the environment, is easy to be applied in large-scale industrialization, accords with the development trend of green chemistry, and is widely concerned by scientists. As early as 1996, Bhaunik et al (Catalysis letters.1996,40,47-50) developed a series of green selective catalytic cyclohexanone for preparing caprolactone by using hydrogen peroxide as an oxidant and titanium silicalite TS-1 as a catalyst. But the selectivity of the target product caprolactone is low, the highest selectivity is only 45.2%, a large amount of intermediate products such as cyclohexanedione, 4-hydroxycyclohexanone and the like exist, and the product separation difficulty is large. Subsequently, Corma et al (Nature.2001,412,423-425) designs and prepares the Sn-Beta molecular sieve, wherein framework Sn atoms provide Lewis acid acidic sites for the molecular sieve, and cyclohexanone molecules can be activated with high selectivity to be oxidized into caprolactone by hydrogen peroxide. However, the Sn-Beta molecular sieve has low tin content (1.5 wt%), which results in a charge ratio (mass ratio of substrate cyclohexanone to catalyst) of only 0.019, and the cyclohexanone conversion rate of only 53% after reaction for 3 hours at 90 ℃, thus resulting in poor economic benefit of the process. Chinese patent CN101161649B introduces composite metal oxide MgO/SnO₂The catalyst for preparing caprolactone by catalyzing cyclohexanone oxidation has high caprolactone selectivity, but MgO/SnO is not provided in the catalyst₂And (4) catalyst cycling stability results. Xu et al (Catalysis communications.2014,55,83-86) studied the catalytic performance of the four silicon germanium molecular sieves IM-12, ITQ-17, ITQ-24 and IM-20 in the oxidation reaction of cyclohexanone, and found that the catalyst has poor cycle stability.

In conclusion, the prior art has the problems of poor product selectivity, low feed ratio or poor catalyst stability, which brings great problems to industrial practical application.

Disclosure of Invention

The invention aims to solve the technical problems of poor target product selectivity, low feed ratio and poor catalyst stability in the prior art, and provides a method for preparing epsilon-caprolactone by catalytic oxidation of cyclohexanone.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a method for producing epsilon-caprolactone, comprising: cyclohexanone and a solution containing hydrogen peroxide are contacted in the presence of SCM-14 molecular sieve and optionally an organic solvent to produce epsilon-caprolactone.

The inventor of the application finds that the preparation of the epsilon-caprolactone by using the SCM-14 molecular sieve for oxidation of the cyclohexanone is beneficial to improving the selectivity of the epsilon-caprolactone, and the expected effect can be still obtained at a higher charge ratio. Meanwhile, the SCM-14 molecular sieve has higher stability.

In some preferred embodiments of the invention, the mass ratio of the SCM-14 molecular sieve to the cyclohexanone is (0.1-10): 1, preferably (0.125-2): 1.

In some preferred embodiments of the present invention, the mass ratio of the cyclohexanone to the hydrogen peroxide is 1 (0.35-1.39).

In some preferred embodiments of the invention, characterized in that,

the SCM-14 molecular sieve (particularly in its as-synthesized or calcined form) has an X-ray diffraction pattern substantially as shown in table a-1 or table a-2 below,

TABLE A-1

(a) ± 0.3 °, (b) varies with 2 θ,

TABLE A-2

(a)＝±0.3°。

According to the present invention, said SCM-14 molecular sieve is selected from the molecular sieves described in CN 109081360A.

According to the invention, in the SCM-14 molecular sieve, SiO is₂With GeO₂Is greater than 1.5, preferably from 1.5 to 8.

In some preferred embodiments of the present invention, the organic solvent is at least one selected from the group consisting of nitrile compounds, ether compounds and alcohol compounds, preferably at least one selected from the group consisting of nitrile compounds.

In some preferred embodiments of the invention, characterized in that said nitrile compounds include acetonitrile and propionitrile; and/or the ether compounds include tetrahydrofuran, 1, 4-dioxane and diisopropyl ether; and/or the alcohol compound comprises C₁-C₃Alcohols, preferably methanol, ethanol, n-propanol and isopropanol.

In some preferred embodiments of the present invention, the mass ratio of the organic solvent to the cyclohexanone is (0-10): 1, preferably (2-6): 1.

In some preferred embodiments of the present invention, the mass fraction of the hydrogen peroxide is 20 wt% to 80 wt%, preferably 30 wt% to 70 wt%, more preferably 40 wt% to 70 wt%, and more preferably 50 wt% to 70 wt%.

In some preferred embodiments of the present invention, the contacting conditions include: the temperature is 50-110 ℃, and the time is 2-8 h.

In some preferred embodiments of the present invention, the contacting conditions include: the temperature is 60-90 ℃ and the time is 4-6 h.

In the context of the present specification, "charge ratio" refers to the mass ratio of cyclohexanone to SCM-14 molecular sieve.

In the context of the present specification, "epsilon-caprolactone" may be simply referred to as "caprolactone".

The invention has the beneficial effects that: (1) according to the invention, the SCM-14 molecular sieve is used as a catalyst, and under the condition of high feed ratio, the conversion rate of cyclohexanone and the selectivity of caprolactone product are both very high; (2) the invention adopts the SCM-14 molecular sieve as the catalyst, has high stability, and does not show catalyst deactivation after being recycled for six times.

Detailed Description

The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to the following description.

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

The product caprolactone is analyzed and characterized by gas chromatography-mass spectrometry (GC-MS), and the product caprolactone yield and the conversion rate of the reaction substrate cyclohexanone are analyzed by Gas Chromatography (GC). The gas chromatograph-mass spectrometer is Agilent 7890A of Agilent, America, a chromatographic column is an HP-5 nonpolar capillary column (30m, 0.53mm), the gas chromatograph is Agilent 7890B, the detector is a hydrogen Flame Ionization Detector (FID), and the chromatographic column is an SE-54 capillary column (30m, 0.53 mm).

The formula for cyclohexanone conversion is:

conversion of cyclohexanone ═ molar amount of cyclohexanone participating in the reaction)/(molar amount of cyclohexanone as a reaction substrate) × 100%.

The yield of the product caprolactone is calculated by the formula:

the yield of caprolactone [% of the product [% of caprolactone produced by the reaction)/(molar amount of cyclohexanone as a reaction substrate ]. times.100%.

The selectivity of caprolactone, a product, is (molar amount of caprolactone produced by the reaction)/(molar amount of cyclohexanone produced by the reaction) × 100%.

Example 1

In the embodiment, the feeding ratio is 2, the mass ratio of cyclohexanone to hydrogen peroxide is 1:0.7, the mass ratio of organic solvent to cyclohexanone is 2, 70 wt% of hydrogen peroxide is selected as the solution containing hydrogen peroxide, and acetonitrile is selected as the organic solvent.

In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 2.0g of cyclohexanone, 2.0g of 70 wt% hydrogen peroxide and 4.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 6h at 90 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 86% and the caprolactone selectivity of 78%.

Example 2

In the embodiment, the feeding ratio is 1, the mass ratio of cyclohexanone to hydrogen peroxide is 1:1.05, the mass ratio of organic solvent to cyclohexanone is 2, hydrogen peroxide is 70 wt% hydrogen peroxide, and acetonitrile is used as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 1.0g of cyclohexanone, 1.5g of 70 wt% hydrogen peroxide and 2.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 6h at 90 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 91% and the caprolactone selectivity of 82%.

Example 3

In the embodiment, the feeding ratio is 4, the mass ratio of cyclohexanone to hydrogen peroxide is 1:1.05, the mass ratio of organic solvent to cyclohexanone is 3, hydrogen peroxide is 70 wt% hydrogen peroxide, and acetonitrile is used as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 4.0g of cyclohexanone, 6.0g of 70 wt% hydrogen peroxide and 12.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 5h at 80 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 73% and the caprolactone selectivity of 76%.

Example 4

In the embodiment, the feeding ratio is 0.5, the mass ratio of cyclohexanone to hydrogen peroxide is 1:0.7, the mass ratio of organic solvent to cyclohexanone is 8, hydrogen peroxide is 70 wt% and acetonitrile is used as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 0.5g of cyclohexanone, 0.5g of 70 wt% hydrogen peroxide and 4.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 4h at 70 ℃, and analyzing the gas phase of the reaction liquid to obtain that the conversion rate of cyclohexanone is 85% and the selectivity of caprolactone is 83%.

Example 5

In the embodiment, the feeding ratio is 0.2, the mass ratio of cyclohexanone to hydrogen peroxide is 1:0.7, the mass ratio of organic solvent to cyclohexanone is 10, hydrogen peroxide is 70 wt% hydrogen peroxide, and acetonitrile is used as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 0.2g of cyclohexanone, 0.2g of 70 wt% hydrogen peroxide and 2.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 4h at 80 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 98% and the caprolactone selectivity of 85%.

Example 6

In the embodiment, the feeding ratio is 2, the mass ratio of cyclohexanone to hydrogen peroxide is 1:1.05, the mass ratio of organic solvent to cyclohexanone is 4, 70 wt% of hydrogen peroxide is selected as hydrogen peroxide, and 1, 4-dioxane is selected as organic solvent.

In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 2.0g of cyclohexanone, 3.0g of 70 wt% hydrogen peroxide and 8.0g of 1, 4-dioxane were charged into a stirred autoclave. Then stirring, reacting for 5h at 70 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 68% and the caprolactone selectivity of 77%.

Example 7

In the embodiment, the feeding ratio is 2, the mass ratio of cyclohexanone to hydrogen peroxide is 1:1.4, the mass ratio of organic solvent to cyclohexanone is 6, hydrogen peroxide is 70 wt% hydrogen peroxide, and tetrahydrofuran is used as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 2.0g of cyclohexanone, 4.0g of 70 wt% hydrogen peroxide and 12.0g of tetrahydrofuran were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 5h at 90 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone with the conversion rate of 89% and the caprolactone selectivity of 81%.

Example 8

In the embodiment, the feeding ratio is 2, the mass ratio of cyclohexanone to hydrogen peroxide is 1:0.7, the mass ratio of organic solvent to cyclohexanone is 6, 70 wt% of hydrogen peroxide is selected as hydrogen peroxide, and 1, 4-dioxane is selected as organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 2.0g of cyclohexanone, 2.0g of 70 wt% hydrogen peroxide and 12.0g of 1, 4-dioxane were charged into a stirred autoclave. Then stirring, reacting for 6h at 80 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 82% and the caprolactone selectivity of 77%.

Example 9

In the embodiment, the feeding ratio is 1, the mass ratio of hydrogen peroxide is 1:0.7, the mass ratio of the organic solvent to cyclohexanone is 3, 50 wt% hydrogen peroxide is selected as hydrogen peroxide, and acetonitrile is selected as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 1.0g of cyclohexanone, 1.4g of 50 wt% hydrogen peroxide and 3.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 4h at 90 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 74% and the caprolactone selectivity of 67%.

Example 10

In the embodiment, the feeding ratio is 3, the mass ratio of cyclohexanone to hydrogen peroxide is 1:1.05, the mass ratio of organic solvent to cyclohexanone is 3, hydrogen peroxide is 30 wt% and acetonitrile is used as the organic solvent. In particular, the amount of the solvent to be used,

1.0g of SCM-14 molecular sieve, 3.0g of cyclohexanone, 10.5g of 30 wt% hydrogen peroxide and 9.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then stirring, reacting for 6h at 90 ℃, and analyzing the gas phase of the reaction liquid to obtain the cyclohexanone conversion rate of 51% and the caprolactone selectivity of 52%.

Example 11

Caprolactone was prepared as in example 1, except that the charge ratio was 5. And the gas-phase analysis of the reaction liquid shows that the conversion rate of the cyclohexanone is 69 percent and the selectivity of the caprolactone is 76 percent.

Example 12

Caprolactone was prepared in the manner as in example 1, except that the mass ratio of cyclohexanone to hydrogen peroxide was 1: 1.39. And (3) analyzing the gas phase of the reaction liquid to obtain that the conversion rate of the cyclohexanone is 91% and the selectivity of the caprolactone is 75%.

Example 13

Caprolactone was prepared in the manner as in example 1, except that the mass ratio of organic solvent to cyclohexanone was 20: 1. And (3) analyzing the gas phase of the reaction liquid to obtain that the conversion rate of the cyclohexanone is 64 percent and the selectivity of the caprolactone is 72 percent.

Example 14

Caprolactone was prepared as in example 1 except that the hydrogen peroxide was 30 wt% and the amount added was 4.6 g. And (3) analyzing the gas phase of the reaction liquid to obtain that the conversion rate of the cyclohexanone is 63% and the selectivity of the caprolactone is 68%.

Example 15

Caprolactone was prepared as in example 1 except that the hydrogen peroxide was 50 wt% and 2.8g was added. And analyzing the gas phase of the reaction liquid to obtain that the conversion rate of the cyclohexanone is 79 percent and the selectivity of the caprolactone is 68 percent.

To more intuitively describe the reaction conditions and results of the above examples, the parameter level results are listed in Table 1.

Example 16

The SCM-14 molecular sieve in the example 1 is washed, dried and put into the next reaction for 6 times of reaction circulation. The feeding ratio is 2, the mass ratio of cyclohexanone to hydrogen peroxide is 1:0.7, the mass ratio of an organic solvent to cyclohexanone is 2, hydrogen peroxide is 70 wt% hydrogen peroxide, and acetonitrile is used as the organic solvent. The reaction conditions were as follows: 1.0g of SCM-14 molecular sieve, 2.0g of cyclohexanone, 2.0g of 70 wt% hydrogen peroxide and 4.0g of acetonitrile were charged into an autoclave equipped with a stirrer. Then, the mixture was stirred and reacted at 90 ℃ for 6 hours, and the reaction solution was analyzed by gas phase analysis. The results are shown in Table 2.

TABLE 2

Number of times of application	Cyclohexanone conversion (%)	Caprolactone selectivity (%)
			1	86	78
2	85	79
			3	86	77
4	84	78
			5	84	77

According to the data in the table 2, the SCM-14 molecular sieve has higher stability when being applied to preparing epsilon-caprolactone by catalytically oxidizing cyclohexanone with hydrogen peroxide.

Comparative example 1

Caprolactone was prepared and tested for recycle properties as in example 16, except that the molecular sieve used was IM-12, and the results are shown in Table 3.

TABLE 3

Number of times of application	Cyclohexanone conversion (%)	Caprolactone selectivity (%)
			1	67	72
2	61	71
			3	53	68
4	36	69
			5	28	66

Comparative example 2

Caprolactone was prepared and tested for recycle properties as in example 16, except that the molecular sieve used was ITQ-17, and the results are shown in Table 4.

TABLE 4

Number of times of application	Cyclohexanone conversion (%)	Caprolactone selectivity (%)
			1	82	73
2	76	70
			3	60	68
4	47	69
			5	32	66

Comparative example 3

Caprolactone was prepared and tested for recycle properties as in example 16, except that the molecular sieve used was ITQ-24, and the results are shown in Table 5.

TABLE 5

Number of times of application	Cyclohexanone conversion (%)	Caprolactone selectivity (%)
			1	69	77
2	58	78
			3	43	75
4	32	74
			5	25	75

Comparative example 4

Caprolactone was prepared and tested for recycling properties as in example 16, except that the molecular sieve used was IM-20, and the results are shown in Table 6.

TABLE 6

Number of times of application	Cyclohexanone conversion (%)	Caprolactone selectivity (%)
			1	73	64
2	65	67
			3	42	63
4	21	64
			5	15	63

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.