WO2018121402A1

WO2018121402A1 - Method for preparing ethylene glycol by photocatalytic conversion of methanol

Info

Publication number: WO2018121402A1
Application number: PCT/CN2017/117719
Authority: WO
Inventors: 王野; 沈泽斌; 谢顺吉; 邓德会; 张庆红
Original assignee: 厦门大学
Priority date: 2016-12-29
Filing date: 2017-12-21
Publication date: 2018-07-05
Also published as: CN106831331A; CN106831331B

Abstract

A method for preparing ethylene glycol by photocatalytic conversion of methanol relating to ethylene glycol. Provided is a method for preparing ethylene glycol by photocatalytic conversion of methanol that features environmental protection, mild reaction conditions, and a high product selectivity. A sulfide semiconductor catalyst or a modified sulfide semiconductor catalyst is added to a solvent, the solvent being a methanol or methanol-water solution. After oxygen in the system is removed, a light source is turned on for a photocatalytic reaction, so as to obtain ethylene glycol. Using a sulfide semiconductor or a modified sulfide semiconductor as a photocatalyst, under the condition of visible light irradiation, methanol can be converted into ethylene glycol after photocatalytic reaction for a certain period of time. The method features environmental protection, mild reaction conditions, and a high product selectivity.

Description

Method for preparing ethylene glycol by photocatalytic conversion of methanol

Technical field

The present invention relates to ethylene glycol, and more particularly to a method for photocatalytic conversion of methanol to ethylene glycol.

Background technique

Ethylene glycol is an important basic chemical raw material, mainly used in the manufacture of resins, polyester fibers, cosmetics and explosives. It can also be used as a solvent and antifreeze. It is widely used. China is the world's largest consumer of ethylene glycol, and it is still not self-sufficient. The import of ethylene glycol has increased year by year. According to the source of raw materials, the production methods of ethylene glycol can be divided into petroleum routes and non-oil routes. At present, the production method of ethylene glycol in the industry mainly adopts a petroleum route, and ethylene obtained from petroleum refining is subjected to gas phase oxidation to obtain ethylene oxide, and ethylene oxide is further subjected to liquid phase catalytic hydration to obtain ethylene glycol. However, due to the shortage of petroleum resources in China, it is necessary to find other ethylene glycol synthesis routes. In recent years, China has made important progress in the research of coal-based ethylene glycol. It has developed a complete set of technology for the catalytic hydrogenation of dimethyl oxalate and dimethyl oxalate to produce ethylene glycol by reacting CO and nitrite. A new process for ethylene glycol. However, the preparation of ethylene glycol from petroleum or coal is a multi-step reaction process, and the reaction conditions are harsh, and there are problems of low reaction efficiency and high energy consumption.

Methanol is the simplest saturated monohydric alcohol and the most widely used alcohol in the industry. It is cheap and easy to obtain. Therefore, the preparation of ethylene glycol using methanol is a highly economical synthetic route. Shozo Yanagida et al. (J. Chem. Soc., Chem. Commun. 1984, 21-22) reported that methanol can be converted to ethylene glycol using a photocatalytic process under ultraviolet light. For example, ethylene glycol can be converted to ethylene glycol by irradiation with ultraviolet light using a ZnS semiconductor catalyst. However, the reactivity is low, the selectivity of ethylene glycol is poor, and ZnS photocorrosion is severe under ultraviolet light conditions, and the catalyst is easily deactivated. In addition, Zhu Zhenping (China Patent CN102070407B) reported that by using ultraviolet light irradiation, titanium dioxide, which is a noble metal such as Pt, Au or Pd, is used as a photocatalyst to photocatalytically convert methanol to ethylene glycol. However, this catalytic system requires not only short-wavelength ultraviolet light but also a noble metal as a cocatalyst. In summary, the above photocatalytic conversion of methanol to ethylene glycol has been reported to require photocatalytic conversion of methanol to ethylene glycol under ultraviolet light irradiation. Photocatalytic conversion of methanol to ethylene glycol using visible light irradiation conditions. No report has been reported.

Summary of the invention

The object of the present invention is to provide a method for preparing ethylene glycol by photocatalytic conversion of methanol with green environmental protection, mild reaction conditions and high product selectivity.

The route of photocatalytic conversion of methanol to ethylene glycol is as follows:

The specific steps of the photocatalytic conversion of methanol to ethylene glycol are as follows:

The sulfide semiconductor catalyst or the modified sulfide semiconductor catalyst is added to a solvent which is a methanol or methanol-water solution. After the oxygen in the system is removed, the light source is turned on for photocatalytic reaction to obtain ethylene glycol.

The sulfide semiconductor catalyst may be a monovalent metal sulfide or a binary metal sulfide, and the monovalent metal sulfide may be selected from the group consisting of CdS, CuS, Cu ₂ S, SnS, In ₂ S ₃ , Bi ₂ S ₃ , Ce _{2 .} At least one of S ₃ , Gd ₂ S ₃ , NiS, MoS ₂ , FeS, or the like, wherein the binary metal sulfide is selected from the group consisting of Zn _x Cd _y S, Cu _x ln _y S, Zn _x ln _y S, and the like. At least one of which 0 < x < 1, 0 < y < 1, the photocatalytic reaction can be carried out under visible light.

The modified sulfide semiconductor catalyst refers to a sulfide semiconductor catalyst supported on a metal, a metal oxide, a metal sulfide, a metal nitride, a metal carbide, or the like, and the amount of the load may be a sulfide by mass percentage. 0.1% to 10% of the semiconductor catalyst; the metal may be at least one selected from the group consisting of Pt, Pd, Au, Ag, Rh, Ru, Ir, Ni, etc.; the metal oxide may be selected from Cr ₂ O ₃ , At least one of MoO ₂ , WO ₃ , MnO ₂ , ZnO, Co ₂ O ₃ , CuO, Fe ₂ O ₃ , V ₂ O _{5 ,} etc.; the metal sulfide may be selected from the group consisting of NiS, MoS ₂ , WS, CuS At least one of Cu ₂ S, PdS, FeS, etc.; the metal carbide may be selected from at least one of Co ₂ C, WC, MoC, etc.; the metal nitride may be selected from Ta ₃ N ₅ , At least one of Ti ₃ N ₄ , GaN, or the like.

The photocatalytic reaction is carried out under visible light conditions.

The mass ratio of the sulfide semiconductor catalyst to the solvent may be 0.001 to 2.

The photocatalytic reaction may take from 1 to 200 hours.

The photocatalytic reaction can be carried out under ultraviolet light.

The light source may be selected from one of a xenon lamp, a mercury lamp, an LED lamp, a tungsten halogen lamp, etc., and the power of the lamp source may be 10 to 1500 W.

The oxygen in the removal system can be used to remove oxygen from the system by pumping with agitation or by introducing an inert gas.

The morphology of the sulfide semiconductor catalyst may be at least one of nanoparticles, nanospheres, nanorods, nanoflowers, nanoplates, nanosheets, and the like.

The invention uses a sulfide semiconductor or a modified sulfide semiconductor as a photocatalyst, and under the condition of visible light irradiation, after photocatalytic reaction for a certain period of time, the methanol can be converted into ethylene glycol, which has the characteristics of green environmental protection, mild reaction conditions and high product selectivity. .

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

(1) The present invention employs the sulfide or modified sulfide semiconductor photocatalyst to photocatalytically convert methanol to produce ethylene glycol under visible light irradiation. Compared with the use of ultraviolet light having a wavelength of less than 400 nm, the photocatalytic reaction using visible light having a wavelength of 400-700 nm has a mild reaction condition and is environmentally friendly.

(2) Ultraviolet light accounts for about 4% of sunlight, and visible light accounts for about 50%. Due to the sulfide or modified sulfide semiconductor catalyst, the photocatalytic conversion of methanol to ethylene glycol can be carried out under visible light irradiation, and the invention significantly improves the utilization of sunlight by the catalyst, and has broad application prospects.

(3) Compared with the existing petroleum route and the coal-to-ethylene glycol route, the invention has the advantages of simple process, mild reaction conditions, high product selectivity, low raw material price and environmental friendliness.

(4) The modified sulfide semiconductor photocatalyst according to the present invention refers to a sulfide semiconductor modified with a load of 0.1% to 10% of a metal, a metal oxide, a metal sulfide, a metal nitride or a metal carbide. The performance of photocatalytic conversion of methanol to ethylene glycol by modified sulfide semiconductor catalyst can be further improved.

(5) The photocatalytic reaction of the present invention is a heterogeneous catalytic reaction, and the catalyst can be recovered and recycled multiple times. In addition, the catalytic reaction can be carried out in pure methanol or a methanol-water mixed solution with few by-products, energy saving and environmental protection.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a liquid chromatogram of Example 5 of the photocatalytic conversion of methanol to ethylene glycol product of the present invention.

detailed description

In order to make the technical problems, technical solutions and beneficial effects of the present invention more clear and clear, the present invention will be further described in detail below with reference to the embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The sulfide semiconductor catalyst or the modified sulfide semiconductor catalyst is added to a solvent which is an aqueous solution of methanol or methanol. After the oxygen in the system is removed, the light source is turned on for photocatalytic reaction to obtain ethylene glycol.

The sulfide semiconductor catalyst or the modified sulfide semiconductor catalyst is added to a methanol or methanol-water solution, and after removing oxygen in the system, the light source is turned on for photocatalytic reaction. After a certain period of exposure, methanol can be converted to ethylene glycol. The sulfide semiconductor catalyst may be a monovalent metal sulfide or a binary metal sulfide, and the monovalent metal sulfide may be selected from the group consisting of CdS, CuS, Cu ₂ S, SnS, In ₂ S ₃ , Bi ₂ S ₃ , Ce _{2 .} At least one of S ₃ , Gd ₂ S ₃ , NiS, MoS ₂ , FeS, and the like, the binary metal sulfide being selected from the group consisting of Zn _x Cd _y S, Cu _x ln _y S, Zn _x ln _y S, and the like. At least one of which 0<x<1, 0<y<1; the modified sulfide semiconductor catalyst refers to one of a supported metal, a metal oxide, a metal sulfide, a metal nitride, a metal carbide, or the like. a sulfide semiconductor catalyst, the amount of which may be 0.1% to 10% by mass of the sulfide semiconductor catalyst; the metal may be selected from the group consisting of Pt, Pd, Au, Ag, Rh, Ru, Ir, Ni, and the like. At least one; the metal oxide may be at least one selected from the group consisting of Cr ₂ O ₃ , MoO ₂ , WO ₃ , MnO ₂ , ZnO, Co ₂ O ₃ , CuO, Fe ₂ O ₃ , V ₂ O _{5 ,} and the like. ; selected from a metal sulfide NiS, at least one _{MoS 2, WS, CuS, Cu} 2 S, PdS, FeS , and the like; a metal carbide selected from Co ₂ C, WC, MoC, etc. At least one; alternatively the metal nitride from at least one of _{_{_{Ta 3 N 5, Ti 3 N}}} 4, GaN and the like.

The photocatalytic reaction is carried out under visible light conditions.

The photocatalytic reaction may take from 1 to 200 hours.

The photocatalytic reaction can be carried out under ultraviolet light.

Specific embodiments are given below.

A certain amount of sulfide or modified sulfide semiconductor photocatalyst is weighed and added to a solution of methanol or methanol water. The gas in the system is removed by pumping with agitation or by introducing an inert gas. Light irradiation is started, and a photocatalytic reaction is carried out, and the photocatalytic reaction is continued for a certain period of time. After the completion of the reaction, the catalyst is separated from the liquid by centrifugation, pouring the liquid phase or standing to separate the precipitate, and pouring the liquid phase, followed by distillation to obtain ethylene glycol.

Example 1

5 mmol of Cd(NO ₃ ) and 5 mmol of Na ₂ S were separately added to 80 mL of water and stirred well for 30 min. The solution was transferred to a 100 mL autoclave, heated at a rate of 5 ° C/min, and maintained at a temperature of 180 ° C for 24 h to obtain hydrothermally synthesized CdS nanoparticles. After washing 3 times by centrifugation, it was placed in an oven at 60 ° C for 12 h, and dried for use. 20 mg of the obtained CdS nanoparticles were taken and added to a solution of 5 mL of methanol water having a mass percentage of 20%. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 300 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 100 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 8.5%, the selectivity of ethylene glycol was 80%, and the yield of ethylene glycol was 6.8%.

Example 2

Add 5 mmol of Cd(NO ₃ ) ₂ and 10 mmol of (NH ₃ ) ₂ CS to 80 mL of anhydrous ethylenediamine. After magnetic stirring, transfer to a 100 mL autoclave and heat up at a rate of 5 ° C/min. CdS nanorods were obtained by maintaining at a temperature of 160 ° C for 48 h. After washing 3 times by centrifugation, it was placed in an oven at 60 ° C for 12 h, and dried for use. After drying and grinding, a solid Cd powder is obtained. 10 mg of the obtained CdS was added to 5 mL of a methanol-water solution having a methanol content of 80% by mass. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 500 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 90 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 13%, the selectivity of ethylene glycol was 85%, and the yield of ethylene glycol was 11%.

Example 3

Add 5 mmol of Cd(NO ₃ ) ₂ and 10 mmol of (NH ₃ ) ₂ CS to 80 mL of anhydrous ethylenediamine. After magnetic stirring, transfer to a 100 ml autoclave and heat up at a rate of 5 ° C/min. The temperature was maintained at 150 ° C for 24 h to obtain CdS nanorods. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, and dried and ground to obtain a CdS solid powder. 0.5 g of the obtained CdS was taken, dispersed in 100 mL of a methanol-aqueous solution having a methanol volume fraction of 20%, and 5 μL of a chloroplatinic acid solution (0.1 g/ml) was added in an amount of 0.1% by weight, stirred and evacuated. The CdS of the noble metal Pt nanoparticles, ie 0.1% Pt-CdS, was obtained by reduction with a 300 W xenon lamp for 1 h. Centrifugal washing and drying and grinding. 5 mg of 0.1% Pt-CdS was added to 5 mL of a methanol-water solution having a mass percentage of methanol of 95%. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 300 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 3 hours. After filtration of the reaction mixture, liquid chromatography analysis showed a methanol conversion of 3.8%, an ethylene glycol selectivity of 76%, and an ethylene glycol yield of 2.9%.

Example 4

Add 5 mmol of Cd(NO ₃ ) ₂ and 10 mmol of (NH ₃ ) ₂ CS to 80 mL of anhydrous ethylenediamine. After magnetic stirring, transfer to a 100 mL autoclave and heat up at a rate of 5 ° C/min. The temperature was maintained at 150 ° C for 24 h to obtain CdS nanorods. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, and dried and ground to obtain a CdS solid powder. 0.5 g of the obtained CdS was taken and dispersed in 100 mL of a methanol-aqueous solution having a methanol volume fraction of 20%, and 0.25 mL of an oxidized town solution (0.1 g/ml) was added in accordance with the loading amount of 5%, stirred and evacuated. It was reduced by 300 W xenon light for 5 h to obtain CdS of supported metal Ni nanoparticles, namely 5% Ni-CdS. Centrifugal washing and drying and grinding. 10 mg of 5% Ni-CdS was added to 5 mL of a methanol-water solution having a mass percentage of methanol of 65%. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 500 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 36 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 16%, the selectivity of ethylene glycol was 82%, and the yield of ethylene glycol was 13%.

Example 5

10 mmol of Cd(NO ₃ ) ₂ , 20 mmol of (NH ₃ ) ₂ CS and 1 mmol of Na ₂ MoO ₆ were sequentially added to 80 mL of anhydrous ethylenediamine, and the mixture was uniformly stirred by magnetic force and transferred to a 100 mL autoclave to 5 The temperature was raised at a rate of ° C/min and maintained at a temperature of 200 ° C for 24 h to obtain a CdS loaded with MoS ₂ , which was 10% MoS ₂ /CdS. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, dried and ground for use. 20 mg of 10% MoS ₂ /CdS was added to a solution of 5 mL of methanol in 25% by mass of methanolic water. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 1500 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 200 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 65%, the selectivity of ethylene glycol was 84%, and the yield of ethylene glycol was 55%.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a liquid chromatogram showing Example 5 of the photocatalytic conversion of methanol to ethylene glycol product of the present invention.

Example 6

Add 5 mmol of Cd(NO ₃ ) ₂ and 10 mmol of (NH ₃ ) ₂ CS to 80 mL of anhydrous ethylenediamine. After magnetic stirring, transfer to a 100 mL autoclave and heat up at a rate of 5 ° C/min. The temperature was maintained at 150 ° C for 18 h to obtain CdS nanorods. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, and dried and ground to obtain a CdS solid powder. 0.5 g of the obtained CdS was taken, dispersed in 100 mL of a methanol-aqueous solution having a methanol volume fraction of 20%, and 25 μL of a palladium chloride solution (0.1 g/ml) was added in an amount of 0.5% by weight, stirred and evacuated. The CdS of the noble metal Pd nanoparticles, ie 0.5% Pd-CdS, was obtained by reduction with a 300 W xenon lamp for 1 h. Centrifugal washing and drying and grinding. 5 mg of 0.5% Pd-CdS was added to 10 mL of a methanol-water solution having a methanol content of 30% by mass. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 500 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 60 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 35%, the selectivity of ethylene glycol was 81%, and the yield of ethylene glycol was 28%.

Example 7

Add 5 mmol of Cd(NO ₃ ) ₂ and 10 mmol of (NH ₃ ) ₂ CS to 80 mL of anhydrous ethylenediamine. After magnetic stirring, transfer to a 100 mL autoclave and heat up at a rate of 5 ° C/min. The temperature was maintained at 150 ° C for 24 h to obtain CdS nanorods. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, and dried and ground to obtain a CdS solid powder. 0.5 g of the obtained CdS was taken, dispersed in 100 mL of a methanol-aqueous solution having a methanol volume fraction of 20%, and 0.25 mL of a copper chloride solution (0.1 g/ml) was added in accordance with the loading amount of 5%, stirred and evacuated. Reduction with 300 W xenon light for 1 h yielded CuO _x loaded CdS, 5% CuO _x -CdS. 20 mg of 5% CuO _x -CdS was added to 5 mL of a methanol-water solution having a 40% by mass of methanol. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 300 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 24 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 18%, the selectivity of ethylene glycol was 75%, and the yield of ethylene glycol was 14%.

Example 8

5 mmol of Bi(NO ₃ ) ₃ and 10 mmol of (NH ₃ ) ₂ CS were added to 80 mL of H ₂ O, stirred magnetically and transferred to a 100 mL autoclave at a rate of 5 ° C/min, at 170 ° C. The temperature was maintained for 36 h to obtain a Bi ₂ S ₃ nanosemiconductor. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, and dried and ground to obtain a Bi ₂ S ₃ solid powder. 20 mg of Bi ₂ S _{3 was} added to 5 mL of 100% methanol solution. After evacuating under stirring or introducing an inert gas to remove oxygen in the system, a 10 W white LED lamp was turned on, and a photocatalytic reaction was carried out under visible light for 24 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 5.1%, the selectivity of ethylene glycol was 45%, and the yield of ethylene glycol was 2.3%.

Example 9

5 mmol of Cu(NO ₃ ) ₂ and 20 mmol of (NH ₃ ) ₂ CS were added to 80 mL of H ₂ O, stirred magnetically and transferred to a 100 mL autoclave at a rate of 5 ° C/min, at 180 ° C. The temperature was maintained for 24 h to obtain CuS nanoparticles. After centrifugation and washing for 3 times, it was placed in an oven at 60 ° C for 12 h, and dried and ground to obtain a CuS solid powder. 1000 mg of CuS was added to a solution of 5 mL of methanolic water having a 10% by mass of methanolic water. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 1000 W tungsten halogen lamp was turned on, and photocatalytic reaction was carried out under visible light for 1 h. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 12%, the selectivity of ethylene glycol was 43%, and the yield of ethylene glycol was 5.2%.

Example 10

9 mmol of Cd(CH ₃ COO) ₂ and 1 mmol of Zn(CH ₃ COO) ₂ were separately added to 80 mL of H ₂ O, stirred magnetically for 30 min, then 20 mmol of CH ₃ C _S NH _{2 was added} , stirring was continued for 30 min, and then transferred to 100 mL. In the high pressure reactor, the temperature was raised at a rate of 5 ° C / min, and maintained at a temperature of 180 ° C for 24 h to obtain a Zn _0.1 Cd _0.9 S nanosemiconductor. 20 mg of the obtained Zn _0.1 Cd _0.9 S semiconductor was taken and added to 10 mL of a methanol-water solution having a methanol content of 50% by mass. After the oxygen in the system was removed, a 300 W mercury lamp was turned on, and a photocatalytic reaction was carried out under ultraviolet light for 48 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 3.5%, the selectivity of ethylene glycol was 71%, and the yield of ethylene glycol was 2.5%.

Comparative example 1

5 mmol of Zn(NO ₃ ) ₂ and 5 mmol of Na ₂ S were added to 80 mL of water and stirred well for 30 min. The solution was transferred to a 100 mL autoclave, heated at a rate of 5 ° C/min, and maintained at a temperature of 180 ° C for 24 h to obtain a hydrothermally synthesized ZnS semiconductor. After washing 3 times by centrifugation, it was placed in an oven at 60 ° C for 12 h, and dried for use. 10 mg of the obtained ZnS semiconductor was taken and added to a solution of 5 mL of methanolic water having a mass percentage of 80%. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 300 W xenon lamp was turned on, and a photocatalytic reaction was carried out under ultraviolet light for 48 hours. After filtration of the reaction mixture, liquid chromatography analysis showed that the conversion of methanol was 1.4%, the selectivity of ethylene glycol was 65%, and the yield of ethylene glycol was 0.91%.

Comparative example 2

5 mmol of Zn(NO ₃ ) ₂ and 5 mmol of Na ₂ S were added to 80 mL of water and stirred well for 30 min. The solution was transferred to a 100 mL autoclave, heated at a rate of 5 ° C/min, and maintained at a temperature of 180 ° C for 24 h to obtain a hydrothermally synthesized ZnS semiconductor. After washing 3 times by centrifugation, it was placed in an oven at 60 ° C for 12 h, and dried for use. 10 mg of the obtained ZnS semiconductor was taken and added to a solution of 5 mL of methanolic water having a mass percentage of 80%. After evacuating with stirring or introducing an inert gas to remove oxygen in the system, a 300 W xenon lamp was turned on, and a photocatalytic reaction was carried out under visible light for 48 hours. After filtration of the reaction liquid, liquid chromatography analysis showed that the conversion of methanol was 0, the selectivity of ethylene glycol was 0, and the yield of ethylene glycol was 0.

Through the comparison of the experimental data of the above Example 1 and the comparative example, it is understood that the methanol conversion rate and the selectivity and the yield of the ethylene glycol are significantly improved by the method of the present invention, and the ZnS is prepared for the methanol under visible light. The reaction of the diol has no effect.

Claims

A route for photocatalytic conversion of methanol to ethylene glycol, characterized in that the route is as follows:
A method for photocatalytic conversion of methanol to ethylene glycol, characterized in that the specific steps are as follows:

The sulfide semiconductor catalyst or the modified sulfide semiconductor catalyst is added to a solvent which is a methanol or methanol-water solution. After the oxygen in the system is removed, the light source is turned on for photocatalytic reaction to obtain ethylene glycol.
A method for preparing ethylene glycol by photocatalytic conversion of methanol according to claim 2, wherein said sulfide semiconductor catalyst is a monovalent metal sulfide or a binary metal sulfide, and said monovalent metal sulfide may be selected from CdS. At least one of CuS, Cu 2 S, SnS, In 2 S 3 , Bi 2 S 3 , Ce 2 S 3 , Gd 2 S 3 , NiS, MoS 2 , FeS, the binary metal sulfide selected from the group consisting of At least one of Zn x Cd y S, Cu x ln y S, Zn x ln y S, wherein 0 < x < 1, 0 < y < 1, the photocatalytic reaction can be carried out under visible light.
A method for photocatalytic conversion of methanol to ethylene glycol according to claim 2, wherein said modified sulfide semiconductor catalyst refers to a supported metal, a metal oxide, a metal sulfide, a metal nitride, a metal carbide. In a sulfide semiconductor catalyst, the amount of the support may be 0.1% to 10% by mass of the sulfide semiconductor catalyst.
A method for photocatalytic conversion of methanol to ethylene glycol according to claim 4, wherein the metal is at least one selected from the group consisting of Pt, Pd, Au, Ag, Rh, Ru, Ir, and Ni; The metal oxide is at least one selected from the group consisting of Cr 2 O 3 , MoO 2 , WO 3 , MnO 2 , ZnO, Co 2 O 3 , CuO, Fe 2 O 3 , and V 2 O 5 ; At least one of NiS, MoS 2 , WS, CuS, Cu 2 S, PdS, FeS; the metal carbide is at least one selected from the group consisting of Co 2 C, WC, and MoC; and the metal nitride is selected from the group consisting of Ta At least one of 3 N 5 , Ti 3 N 4 , and GaN.
A method for photocatalytic conversion of methanol to ethylene glycol according to claim 2, wherein the photocatalytic reaction is carried out under visible light or ultraviolet light.
A method for photocatalytic conversion of methanol to ethylene glycol according to claim 2, wherein the mass ratio of the sulfide semiconductor catalyst to the solvent is 0.001 to 2.
A method for photocatalytic conversion of methanol to ethylene glycol according to claim 2, wherein the photocatalytic reaction is carried out for a period of from 1 to 200 hours.
The method for preparing ethylene glycol by photocatalytic conversion of methanol according to claim 2, wherein the light source is selected from the group consisting of a xenon lamp, a mercury lamp, an LED lamp, and a tungsten halogen lamp, and the power of the lamp source is 10. ~1500W.
A method for photocatalytic conversion of methanol to ethylene glycol according to claim 2, wherein the oxygen in the removal system is removed by evacuating or activating an inert gas; The morphology of the sulfide semiconductor catalyst may be at least one of nanoparticles, nanospheres, nanorods, nanoflowers, nanoplates, and nanosheets.