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 沈建兵 柴文玉 张芳江 于 2021-07-16 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200～350℃的反应温度下将6-羟基己酸蒸汽与惰性气体的混合物进行催化反应的步骤。该制备方法使用6-羟基己酸蒸汽与惰性气体作为原料流,在200～350℃下进行分子内酯化反应即可得到ε-己内酯,该反应只产生一当量的废水,对环境污染小,原料的转化率和反应的选择性高,后处理过程简单,有利于应用于工业生产中。(The invention provides a preparation method of epsilon-caprolactone, which comprises the step of carrying out catalytic reaction on a mixture of 6-hydroxycaproic acid steam and inert gas at the reaction temperature of 200-350 ℃. According to the preparation method, the 6-hydroxycaproic acid steam and the inert gas are used as raw materials, intramolecular esterification reaction is carried out at 200-350 ℃, and the epsilon-caprolactone can be obtained.)

1. The preparation method of the epsilon-caprolactone is characterized by comprising the step of carrying out catalytic reaction on a mixture of 6-hydroxycaproic acid steam and inert gas at the reaction temperature of 200-350 ℃.

2. The method of claim 1, comprising: and (2) enabling the mixture of 6-hydroxycaproic acid steam and inert gas to pass through a reactor loaded with a catalyst at the temperature of 200-350 ℃ for catalytic reaction, and collecting reaction products for 12 hours at the temperature of 10-20 ℃ by using a cooling receiver to obtain epsilon-caprolactone.

3. The preparation method according to claim 1 or 2, wherein in the catalytic reaction, the catalyst is a supported catalyst loaded with metal oxide, the carrier is at least one selected from silica and alumina, and the metal in the metal oxide is at least one metal element selected from main groups IIA-VA and sub-groups IB-VIIIB.

4. The method according to any one of claims 1 to 3, wherein the mass of the metal oxide is 5 to 25% of the mass of the catalyst.

5. The production method according to any one of claims 1 to 4, wherein the metal oxide is at least one selected from the group consisting of manganese oxide, cobalt oxide, barium oxide, strontium oxide, silver oxide, ruthenium oxide, rhodium oxide, palladium oxide, antimony oxide, and nickel oxide.

6. The production method according to any one of claims 1 to 5, wherein the mass ratio of the 6-hydroxyhexanoic acid to the inert gas is 1 (100 to 50000).

7. The method according to any one of claims 1 to 6, wherein the reaction temperature is 280 to 320 ℃.

8. The method according to any one of claims 1 to 7, wherein the inert gas is at least one selected from nitrogen, argon, and carbon dioxide.

9. The method according to any one of claims 1 to 8, wherein the mass space velocity of the 6-hydroxycaproic acid vapor is 0.02 to 0.5h^-1。

10. The method according to any one of claims 1 to 9, wherein the pressure of the catalytic reaction is 0 to 1 Mpa.

Technical Field

The invention belongs to the technical field of organic chemical industry, and relates to a preparation method of epsilon-caprolactone.

Background

Epsilon-caprolactone is a new type of polyester monomer, and is mainly used in the production of synthetic rubber, synthetic fiber and synthetic resin, and in the production of caprolactam, adhesive, paint, epoxy resin diluent and solvent, and may be blended with other various resins to improve their properties such as gloss, transparency and anti-sticking property, and in addition, it may be used to synthesize polycaprolactone. Poly epsilon-caprolactone is one of the degradable plastics at the present leading edge, has wide application, can also be used as a raw material of high-performance fiber, and the fiber prepared by the poly epsilon-caprolactone has the advantages of air permeability, high strength, high elasticity and wearing comfort. Because the poly-epsilon-caprolactone has degradability like polylactic acid, the poly-epsilon-caprolactone can be widely applied to medical materials, such as medical suture lines, bone repair, artificial cartilage, artificial skin, nerves, blood vessels and the like.

At present, the industrial large-scale production method of epsilon-caprolactone mainly adopts an oxidant to carry out Bayer-Villiger (Bayer-Villiger) oxidation on cyclohexanone, but the method generates more three wastes and has larger risk coefficient of oxidation reaction.

Patent US3189619A discloses a process for the reaction of 6-hydroxycaproic esters with trialkyl borates, followed by conversion of the reaction product to caprolactone under reduced pressure of 200 ℃ and heating at 250 ℃.

Patent FR1474903A discloses that caprolactone is distilled off continuously by heating 6-hydroxycaproic ester in the liquid phase to 150-350 ℃ under reduced pressure in the presence of oxides such as magnesium oxide, zinc oxide, cadmium oxide, aluminum oxide and titanium dioxide.

However, the above two methods have a disadvantage that the 6-hydroxycaproic ester is polymerized under heating to result in a low yield.

Patent US5068361A discloses a method for preparing caprolactone by heating 6-hydroxycaproic ester under the catalytic conditions of an oxidation catalyst at 450 ℃ and passing the 6-hydroxycaproic ester vapor through a fixed bed or fluidized bed loaded with an oxidation catalyst together with an inert carrier gas, but it is described that if the 6-hydroxycaproic ester is vaporized together with an ether solvent such as 1, 4-dioxane or tetrahydrofuran at 180 ℃ and 300 ℃, the reaction is facilitated, but the use of an organic solvent may affect human health and cause environmental pollution.

Patent CN1449394A discloses a method for obtaining caprolactone by using a mixed solution of 6-hydroxycaproic acid and 20-95 wt% of water as a raw material stream, mixing the mixed solution with nitrogen and passing through a reaction zone filled with a catalyst capable of effectively promoting the conversion of hydroxy acid into corresponding lactone, wherein after conditions are optimized, the method can achieve 96% of raw material conversion rate and 95% of product selectivity, but the method uses 6-hydroxycaproic acid and water as raw material streams, a large amount of waste water is generated in the later period, the post-treatment also needs water-oil separation and recovery, and the production efficiency is difficult to improve.

Disclosure of Invention

The invention provides a preparation method of epsilon-caprolactone, which uses 6-hydroxycaproic acid steam and inert gas as raw materials to carry out intramolecular esterification reaction at 200-350 ℃ to obtain the epsilon-caprolactone.

The invention provides a preparation method of epsilon-caprolactone, which comprises the step of carrying out catalytic reaction on a mixture of 6-hydroxycaproic acid steam and inert gas at the reaction temperature of 200-350 ℃.

The preparation method comprises the following steps: and (2) enabling the mixture of 6-hydroxycaproic acid steam and inert gas to pass through a reactor loaded with a catalyst at the temperature of 200-350 ℃ for catalytic reaction, and collecting reaction products for 12 hours at the temperature of 10-20 ℃ by using a cooling receiver to obtain epsilon-caprolactone.

The preparation method as described above, wherein in the catalytic reaction, the catalyst is a supported catalyst loaded with metal oxide, the carrier is selected from at least one of silica and alumina, and the metal in the metal oxide is selected from at least one metal element in main groups IIA-VA and sub-groups IB-VIIIB.

The production method as described above, wherein the mass of the metal oxide accounts for 5 to 25% of the mass of the catalyst.

The production method as described above, wherein the metal oxide is at least one selected from the group consisting of manganese oxide, cobalt oxide, barium oxide, strontium oxide, silver oxide, ruthenium oxide, rhodium oxide, palladium oxide, antimony oxide, and nickel oxide.

The preparation method comprises the step of mixing 6-hydroxycaproic acid with inert gas in a mass ratio of 1 (100-50000).

The preparation method comprises the step of carrying out reaction at the reaction temperature of 280-320 ℃.

The production method as described above, wherein the inert gas is at least one selected from nitrogen, argon, and carbon dioxide.

The preparation method comprises the step of controlling the mass space velocity of the 6-hydroxycaproic acid steam to be 0.02-0.5 h^-1。

The preparation method as described above, wherein the pressure of the catalytic reaction is 0 to 1 Mpa.

The preparation method of the epsilon-caprolactone provided by the invention has the advantages of high conversion rate of raw materials and selectivity of the epsilon-caprolactone, less wastewater generated by reaction, simple post-treatment process and less environmental pollution, and is beneficial to being applied to industrial production.

Drawings

FIG. 1 is a gas chromatogram of the product of example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of epsilon-caprolactone, which comprises the step of carrying out catalytic reaction on a mixture of 6-hydroxycaproic acid steam and inert gas at the reaction temperature of 200-350 ℃.

The method uses the mixture of the 6-hydroxycaproic acid steam and the inert gas as the raw material flow, the inert gas can play a role in diluting the 6-hydroxycaproic acid, the intermolecular polymerization reaction of the 6-hydroxycaproic acid can be avoided to generate a by-product 6-hydroxycaproic acid polymer, and in addition, the steam phase of the 6-hydroxycaproic acid is mixed with the inert gas, so that the 6-hydroxycaproic acid can be uniformly dispersed in the inert gas, and the intramolecular esterification is further facilitated.

The preparation method of the epsilon-caprolactone provided by the invention only needs to take the mixture of the 6-hydroxycaproic acid steam and the inert gas as a raw material flow, does not need to add other aqueous solvents or organic solvents, only generates one equivalent of wastewater after the reaction is finished, generates less three wastes, is environment-friendly, does not need to use other aqueous solvents or organic solvents, and can also enable the reaction to have lower cost.

In the present invention, the source of the raw material 6-hydroxycaproic acid is not particularly limited, and 6-hydroxycaproic acid can be produced by a method which is conventional in the art.

For example, 6-hydroxyhexanoic acid can be obtained by oxidation of 6-hydroxyhexanal with reference to a commonly used preparation method, or 6-hydroxyhexanoic acid can be obtained by recovering a waste stream resulting from a Bayer-Villiger reaction of cyclohexanone with peroxy acids, and the like.

It is understood that the higher the purity of the raw material 6-hydroxycaproic acid used, the more advantageous the avoidance of side reactions in the reaction and the achievement of high conversion and selectivity of the reaction. The purity of the 6-hydroxycaproic acid used in the invention is generally more than or equal to 97%.

In a specific embodiment, the preparation method of epsilon-caprolactone provided by the invention comprises the following steps: and (2) carrying out catalytic reaction on a mixture of 6-hydroxycaproic acid steam and inert gas in a reactor loaded with a catalyst at the reaction temperature of 200-350 ℃, and collecting a reaction product for 12 hours at the temperature of 10-20 ℃ by using a cooling receiver to obtain epsilon-caprolactone.

The invention does not limit the specific type of the reactor used in the catalytic reaction, and the reactors commonly used in the field can be used, for example, a fixed bed reactor and a fluidized bed reactor can both achieve better catalytic effect.

And (3) after the catalytic reaction is finished, keeping the product flow in a gas phase state at 200-350 ℃, cooling the product flow in a cooling receiver, controlling the temperature of the cooling receiver to be 10-20 ℃, and obtaining the epsilon-caprolactone with higher purity without further purification.

The catalyst used in the catalytic reaction is a supported catalyst on which a metal oxide is supported.

Wherein, the carrier is selected from at least one of silicon dioxide and alumina. Illustratively, the support may be silica, alumina, or a mixture of silica and alumina.

When the carrier is selected from a mixture of silica and alumina, controlling the mass ratio of the silica to the alumina to be 1: 3, the catalyst has better catalytic effect.

Wherein the metal in the metal oxide is at least one metal element selected from main groups IIA-VA and auxiliary groups IB-VIIIB in the periodic table of elements.

The metal oxide in the catalyst as described above may further preferably be at least one selected from manganese oxide, cobalt oxide, barium oxide, strontium oxide, silver oxide, ruthenium oxide, rhodium oxide, palladium oxide, antimony oxide, and nickel oxide.

Further, when the mass of the metal oxide accounts for 5-25% of the mass of the catalyst, the catalyst can exert a good catalytic effect, and the 6-hydroxycaproic acid can be converted into epsilon-caprolactone with high conversion rate and high selectivity.

The mass ratio of 6-hydroxycaproic acid to inert gas in the feed stream is a key factor for improving the reaction selectivity, when the mass ratio of 6-hydroxycaproic acid to inert gas is controlled to be 1: (100-50000), the inert gas can play a good role in diluting 6-hydroxycaproic acid, and the self-polymerization reaction of 6-hydroxycaproic acid can be effectively avoided.

The selection of the inert gas is not particularly limited in the present invention, and a commonly used inert gas such as nitrogen, argon, carbon dioxide or a mixture thereof may be used. Generally, the use of a wide source of nitrogen as the inert gas enables the reaction to be carried out at a lower cost.

Further, the temperature of the catalytic reaction is preferably 280 to 320 ℃. Under the reaction temperature, on one hand, the 6-hydroxycaproic acid can be kept in a steam state in the reaction process, and on the other hand, the reaction can be helped to reach the activation energy, so that the reaction is more favorably carried out.

Space velocity refers to the amount of gas treated by a unit volume of catalyst per unit time under a specified condition, and has two expression forms, one is volume space velocity and the other is mass space velocity, wherein the volume space velocity can be obtained according to the volume flow of raw materials/the volume of the catalyst, and the mass space velocity can be obtained according to the mass flow of the raw materials/the mass of the catalyst.

For a given plant, the feed rate is increased by an increase in hourly space velocity, with a high space velocity meaning more feedstock passes over the catalyst per unit time, short residence time of the feedstock on the catalyst, and shallow depth of reaction. In contrast, a lower space velocity means that more catalyst is required at the same throughput, and the economics are poor.

According to the reactor used, the activity of the catalyst, the property of the 6-hydroxycaproic acid, the purity requirement of the epsilon-caprolactone product and other comprehensive factors, the mass space velocity of the 6-hydroxycaproic acid steam is determined to be more suitable and is 0.02-0.5 h^-1More preferably 0.06 to 0.12 hours^-1。

Furthermore, the catalytic reaction can be carried out under 0-1 MPa, and the reaction under high pressure or negative pressure is not needed, so that the method is safe.

The preparation process of epsilon-caprolactone provided by the present invention will be further described with reference to specific examples.

In the following examples, all starting materials and reagents were prepared by either commercially available or conventional methods, unless otherwise specified.

Example 1

The preparation method of epsilon-caprolactone comprises the following steps:

1. a stainless steel fixed bed with an inner diameter of 22mm, a constant temperature interval length of 200mm and a thermocouple with an outer diameter of 3mm is selected as a reactor.

Inert ceramic balls (diameter is 2-3mm) are filled outside the constant temperature region of the reactor, and 70mL of 20-40 mesh silicon dioxide supported manganese oxide catalyst is filled in the constant temperature region.

Wherein, the catalyst comprises 12 percent of manganese oxide and 88 percent of silicon dioxide by mass percentage.

2. Heating a stainless steel fixed bed reactor to 300 ℃ at the heating rate of 1-2 ℃/min under normal pressure, introducing nitrogen into the reactor at the flow rate of 600mL/min, introducing 6-hydroxycaproic acid steam with the purity of 99% at the flow rate of 6g/h after introducing the nitrogen for 30 minutes, and collecting a product stream in a cooling receiver for 12 hours at the temperature of 15 ℃.

Wherein the mass ratio of the 6-hydroxycaproic acid steam to the nitrogen is 1: the mass space velocity of the 450, 6-hydroxycaproic acid steam passing through the stainless steel fixed bed reactor is 0.06h^-1。

Analysis of the collected product was performed using gas chromatography under the following analytical test conditions:

a. the instrument comprises the following steps: agilent a7890 gas chromatograph;

b. a chromatographic column: DB-1 capillary column connected with hydrogen flame detector (FID);

chromatographic carrier gas: high-purity He;

c. temperature of the gasification chamber: 250 ℃;

d. temperature of the column box: keeping the temperature at 150 ℃ for 5min, then increasing the temperature to 280 ℃ at the heating rate of 10 ℃/min, and keeping the temperature for 5 min.

FIG. 1 is a gas chromatogram of the product of example 1, and the relevant information in Table 1 can be obtained after processing the gas chromatogram of FIG. 1:

TABLE 1

Retention time/min	Peak area/(pA. s)	content/Peak area	Normalized group/%)	Component name
					5.480	1.88024*105	1.00000	95.567084	Epsilon-caprolactone
5.631	3856.90381	1.00000	1.960351	Impurities
					6.114	4864.66406	1.00000	2.472565	6-Hydroxyhexanoic acid

As can be analyzed from the data in Table 1, the conversion of 6-hydroxycaproic acid in this example was 97.5% and the selectivity of. epsilon. -caprolactone was 98.0%.

Example 2

The preparation method of epsilon-caprolactone comprises the following steps:

1. a stainless steel fixed bed with an inner diameter of 22mm, a constant temperature interval length of 200mm and a thermocouple with an outer diameter of 3mm is selected as a reactor.

Inert ceramic balls (diameter is 2-3mm) are filled outside a constant temperature region of the reactor, and 70mL of gamma-alumina supported manganese oxide catalyst with 20-40 meshes is filled in the constant temperature region.

Wherein, the catalyst comprises 10 percent of manganese oxide and 90 percent of silicon dioxide by mass percent.

2. The temperature of a stainless steel fixed bed reactor is raised to 320 ℃ at the heating rate of 1-2 ℃/min under normal pressure, nitrogen is introduced into the reactor at the flow rate of 900mL/min, 6-hydroxycaproic acid steam with the purity of 99 percent is introduced at the flow rate of 6g/h after 30 minutes of introduction, and the product stream is collected in a cooling receiver for 12 hours at the temperature of 15 ℃.

Wherein the mass ratio of the 6-hydroxycaproic acid steam to the nitrogen is 1: 675,6The mass space velocity of the hydroxycaproic acid steam passing through the stainless steel fixed bed reactor is 0.06h^-1。

The collected product was analyzed by gas chromatography under the same test conditions as in example 1, and it was found that the conversion of 6-hydroxycaproic acid was 98.0% and the selectivity of epsilon-caprolactone was 96.9%.

Example 3

The preparation method of epsilon-caprolactone comprises the following steps:

1. a stainless steel fixed bed with an inner diameter of 22mm, a constant temperature interval length of 200mm and a thermocouple with an outer diameter of 3mm is selected as a reactor.

Inert ceramic balls (diameter is 2-3mm) are filled outside the constant temperature region of the reactor, and 70mL of gamma-alumina with 20-40 meshes and cobalt oxide catalyst loaded by silicon dioxide are filled in the constant temperature region.

Wherein, the catalyst comprises 5 percent of cobalt oxide, 50 percent of silicon dioxide and 45 percent of gamma-alumina by mass percentage.

2. The temperature of a stainless steel fixed bed reactor program is raised to 350 ℃ at the heating rate of 1-2 ℃/min under normal pressure, nitrogen is introduced into the reactor at the flow rate of 6000mL/min, 6-hydroxycaproic acid steam with the purity of 99 percent is introduced at the flow rate of 12g/h after 30 minutes of introduction, and a product stream is collected in a cooling receiver for 12 hours at the temperature of 15 ℃.

Wherein the mass ratio of the 6-hydroxycaproic acid steam to the nitrogen is 1: 2250, 6-Hydroxyhexanoic acid vapor was passed through a stainless steel fixed bed reactor at a mass space velocity of 0.12h^-1。

The collected product was analyzed by gas chromatography under the same test conditions as in example 1, and it was found that the conversion of 6-hydroxycaproic acid was 99.1% and the selectivity of epsilon-caprolactone was 93.8%.

Example 4

The preparation method of epsilon-caprolactone comprises the following steps:

1. a stainless steel fixed bed with an inner diameter of 22mm, a constant temperature interval length of 200mm and a thermocouple with an outer diameter of 3mm is selected as a reactor.

Inert ceramic balls (diameter is 2-3mm) are filled outside the constant temperature region of the reactor, and 70mL of gamma-alumina with 20-40 meshes and cobalt oxide catalyst loaded by silicon dioxide are filled in the constant temperature region.

Wherein, the catalyst comprises 5 percent of cobalt oxide, 50 percent of silicon dioxide and 45 percent of gamma-alumina by mass percentage.

2. The temperature of a stainless steel fixed bed reactor is raised to 320 ℃ at the heating rate of 1-2 ℃/min under normal pressure, nitrogen is introduced into the reactor at the flow rate of 600mL/min, 6-hydroxycaproic acid steam with the purity of 99 percent is introduced at the flow rate of 6g/h after 30 minutes of introduction, and the product stream is collected in a cooling receiver for 12 hours at the temperature of 15 ℃.

Wherein the mass ratio of the 6-hydroxycaproic acid steam to the nitrogen is 1: the mass space velocity of the 450, 6-hydroxycaproic acid steam passing through the stainless steel fixed bed reactor is 0.06h^-1。

The collected product was analyzed by gas chromatography under the same test conditions as in example 1, and it was found that the conversion of 6-hydroxycaproic acid was 95.6% and the selectivity of e-caprolactone was 98.4%.

Example 5

The preparation method of epsilon-caprolactone comprises the following steps:

1. a stainless steel fixed bed with an inner diameter of 22mm, a constant temperature interval length of 200mm and a thermocouple with an outer diameter of 3mm is selected as a reactor.

Inert ceramic balls (diameter is 2-3mm) are filled outside the constant temperature region of the reactor, and 70mL of gamma-alumina with 20-40 meshes and cobalt oxide catalyst loaded by silicon dioxide are filled in the constant temperature region.

Wherein, the catalyst comprises 5 percent of cobalt oxide, 50 percent of silicon dioxide and 45 percent of gamma-alumina by mass percentage.

2. The temperature of a stainless steel fixed bed reactor is raised to 320 ℃ at the heating rate of 1-2 ℃/min under normal pressure, nitrogen is introduced into the reactor at the flow rate of 600mL/min, 6-hydroxycaproic acid steam with the purity of 99 percent is introduced at the flow rate of 8g/h after 30 minutes of introduction, and the product stream is collected in a cooling receiver for 12 hours at the temperature of 15 ℃.

Wherein the mass ratio of the 6-hydroxycaproic acid steam to the nitrogen is 1: 337.5, 6-Hydroxyhexanoic acid vapor passing through a stainless steel fixed bed reactor at a mass space velocity of 0.08h^-1。

The collected product was analyzed by gas chromatography under the same test conditions as in example 1, and it was found that the conversion of 6-hydroxycaproic acid was 97.1% and the selectivity of epsilon-caprolactone was 97.9%.

Example 6

The preparation method of epsilon-caprolactone comprises the following steps:

1. a stainless steel fixed bed with an inner diameter of 22mm, a constant temperature interval length of 200mm and a thermocouple with an outer diameter of 3mm is selected as a reactor.

Inert ceramic balls (diameter is 2-3mm) are filled outside the constant temperature region of the reactor, and 70mL of gamma-alumina with 20-40 meshes and cobalt oxide catalyst loaded by silicon dioxide are filled in the constant temperature region.

Wherein, the catalyst comprises 5 percent of cobalt oxide, 50 percent of silicon dioxide and 45 percent of gamma-alumina by mass percentage.

2. Heating a stainless steel fixed bed reactor to 320 ℃ at the heating rate of 1-2 ℃/min under normal pressure, introducing nitrogen into the reactor at the flow rate of 600mL/min, introducing 6-hydroxycaproic acid steam with the purity of 99% at the flow rate of 12g/h after introducing the nitrogen for 30 minutes, and collecting a product stream in a cooling receiver for 12 hours at the temperature of 15 ℃.

Wherein the mass ratio of the 6-hydroxycaproic acid steam to the nitrogen is 1: the mass space velocity of the 225, 6-hydroxycaproic acid steam passing through the stainless steel fixed bed reactor is 0.12h^-1。

The collected product was analyzed by gas chromatography under the same test conditions as in example 1, and it was found that the conversion of 6-hydroxycaproic acid was 90.6% and the selectivity of epsilon-caprolactone was 97.8%.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.