CATALYST FOR OXIDATIVE CARBONYLATION OF METHANOL TO SYNTHESIZE DIMETHYL CARBONATE, AND PREPARATION METHOD AND APPLICATIONS THEREOF

Abstract

A catalyst for oxidative carbonylation of methanol to obtain dimethyl carbonate, a preparation method and applications thereof are disclosed. The catalyst includes a carrier being a porous carbon-nitrogen material, and an active component being Cu, where the weight of Cu accounts for 5-15 wt % of the total weight of the catalyst. The catalyst exhibits good catalytic activity in the reaction of methanol oxidative carbonylation to synthesize dimethyl carbonate, has high space-time yield and selectivity, and the catalyst and the product are easy to separate.

Claims

1. A catalyst, comprising: a carrier being a nitrogen-doped hirarchical porous carbon (NHPC);and an active component being Cu; wherein a weight of Cu in the catalyst accounts for 5-15 wt % of a total weight of the catalyst.

2. The catalyst of claim 1, wherein the NHPC of the carrier in the catalyst is obtained by mixing cellulose powder, ammonium oxalate, and sodium bicarbonate with a mass ratio of 1:(1-6):(1-6) and calcining at 700-900° C.

3. The catalyst of claim 1, wherein the active component Cu in the catalyst is derived from copper sulfate, copper chloride, copper nitrate, or cuprous chloride.

4. A method of preparing a catalyst, the catalyst comprising a carrier being a NHPC material and an active component being Cu, the method comprising: preparation of NHPC material, comprising: mixing cellulose powder, ammonium oxalate, and sodium bicarbonate with a mass ratio of 1:(1-6):(1-6) in nitrogen atmosphere and calcining at 700-900° C. for 1 h, after the calcination is finished, cooling to room temperature to obtain a black solid, dispersing the obtained black solid in deionized water, filtering and drying to obtain the NHPC; preparation of a copper-based catalyst supported by the NHPC, comprising: dissolving a copper salt in concentrated hydrochloric acid, adding deionized water, adding the porous carbon-nitrogen material obtained in the previous operation into the above solution, mixing and stirring sufficiently, vacuum drying after separation, and calcining in a 10% H.sub.2/N.sub.2 atmosphere in a reducing furnace at 100-600° C. for 1-5 h, and cooling to obtain the copper-based catalyst supported by the porous carbon-nitrogen material.

5. The method of claim 4, wherein the copper salt comprises at least one selected from the group consisting of copper sulfate, copper chloride, copper nitrate, and cuprous chloride.

6. The method of claim 4, wherein a weight of Cu in the catalyst accounts for 5-15 wt % of a total weight of the catalyst.

7. Use of a catalyst for oxidative carbonylation of methanol to synthesize dimethyl carbonate, the catalyst comprising a carrier being a NHPC material and an active component being Cu, wherein a conversion rate of methanol reaches 13.4%, a selectivity of dimethyl carbonate reaches 94.8%, and a space-time yield reaches 14.5˜22.1 g/(g h).

8. The use of claim 7, wherein the porous carbon-nitrogen material of the carrier in the catalyst is obtained by mixing cellulose powder, ammonium oxalate, and sodium bicarbonate with a mass ratio of 1:(1-6):(1-6) and calcining at 700-900° C.

9. The use of claim 7, wherein the active component Cu in the catalyst is derived from copper sulfate, copper chloride, copper nitrate, or cuprous chloride.

10. The use of claim 7, wherein the methanol and the catalyst are added into an autoclave, air in the autoclave is replaced with CO, then the autoclave is filled CO and O.sub.2 in turn, and then cooled in a water bath after the reaction to obtain a reaction liquid, and a solid catalyst is separated from the obtained reaction liquid to obtain dimethyl carbonate.

11. The use of claim 10, wherein a volume ratio of CO:O.sub.2 is 9:1, a system pressure is 2-5 MPa, and a reaction temperature is 100-200° C.

12. A method for synthesizing dimethyl carbonate using methanol oxidative carbonylation, comprising using the catalyst of claim 1.

13. The method of claim 12, wherein a conversion rate of methanol reaches 13.4%, a selectivity of dimethyl carbonate reaches 94.8%, and a space-time yield reaches 14.5-22.1 g/(g.Math.h).

14. The method of claim 12, wherein the porous carbon-nitrogen material of the carrier in the catalyst is obtained by mixing cellulose powder, ammonium oxalate, and sodium bicarbonate with a mass ratio of 1:(1-6):(1-6) and calcining at 700-900° C.

15. The method of claim 12, wherein the active component Cu in the catalyst is derived from copper sulfate, copper chloride, copper nitrate, or cuprous chloride.

16. The method of claim 12, wherein the methanol and the catalyst are added into an autoclave, the air in the autoclave is replaced with CO, then the autoclave is filled CO and O.sub.2 in turn, and then cooled in a water bath after the reaction to obtain a reaction liquid, and a solid catalyst is separated from the obtained reaction liquid to obtain dimethyl carbonate.

17. The method of claim 12, wherein a volume ratio of CO:O.sub.2 is 9:1, a system pressure is 2-5 MPa, and a reaction temperature is 100-200° C.

Description

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0024] FIG. 1 shows an X-ray diffraction pattern of a copper-based catalyst carried by a porous carbon-nitrogen material, where the ordinate in the figure represents the diffraction intensity, the abscissa represents the diffraction angle 2 θ, and the standard peaks 43°, 50°, and 73.9° are the characteristic diffraction peaks of copper element. It can be seen from the figure that the copper species is well supported on the carrier. The catalyst uses CuCl as the active component precursor, and the characteristic diffraction peaks of CuCl almost completely disappear, indicating that CuCl is well and highly dispersed on the surface of the carrier.

DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain the present application, rather than limit the present application.

[0026] The raw materials used in the specific embodiments of the present disclosure are commercially available.

Embodiment 1

[0027] In this embodiment, regarding the catalyst used for the oxidative carbonylation of methanol to synthesize dimethyl carbonate, the carrier of the catalyst is a porous carbon-nitrogen material, and the active component is copper.

(1) Catalyst Preparation

[0028] Weigh 6 g of cellulose powder, 18 g of ammonium oxalate, and 18 g of sodium bicarbonate, and mix and grind them uniformly, and then transfer them to a tube furnace for calcination. During the calcination, the flow rate of N.sub.2 is 80 mL/min, and the temperature is programmed to rise to 800° C. at a heating rate of 10° C./min for 1 h.

[0029] At the end of calcination, the obtained black solid is dispersed in 1000 mL of deionized water, fully stirred at room temperature for 24 h, washed with deionized water and suction- filtered until the solution becomes neutral, and then the obtained black solid material is put into a 75° C. vacuum oven for drying, and after drying for 6 h, the porous carbon-nitrogen material is obtained without grinding.

[0030] Dissolve 0.169 g of CuCl in 15 mL of concentrated hydrochloric acid, add 45 mL of deionized water, and then add 2.0 g of porous carbon-nitrogen material ensuring that the mass fraction of Cu is 5%. After appropriate stirring, the solution is sonicated for 1 h, then the solution is stirred at room temperature for 10 h, and the mixture is rotary evaporated to obtain a black solid.

[0031] The black solid is dried in a vacuum oven at 75° C. for 3 h, then fully ground, and then transferred to a reduction furnace for calcination. During the calcination, the gas atmosphere is 10% H.sub.2/N.sub.2, and the gas flow rate is 40 mL/min. and the temperature is programmed to rise to 300° C. at a heating rate of 4° C./min for 2 h. After the reduction is completed, the original atmosphere is maintained and it is allowed to cool to room temperature to obtain 5 wt % Cu/NHPC-300-2.

(2) Catalyst Application

[0032] 10 mL of methanol and 0.3 g of the prepared 5 wt % Cu/NHPC-300-2 catalyst are added to a 100 mL autoclave. After replacing the air in the autoclave with CO, 3.6 MPa CO and 0.4 MPa O.sub.2 were charged in turn. After reacting at 120° C. for 0.5 h, it is cooled in a water bath, and the obtained reaction liquid is separated from the solid catalyst to obtain a clear liquid.

(3) Analysis of Results

[0033] The product is analyzed by gas chromatography using ethanol as the internal standard. Analysis results of methanol conversion, space-time yield, and dimethyl carbonate selectivity are as follows:

TABLE-US-00001 Conv. MeOH(%) S.sub.DMC(%) S.sub.DMM(%) STY(g/(g .Math. h)) 13.38 94.79 3.44 18.8

Embodiment 2

(1) Catalyst Preparation

[0034] Weight 6 g of cellulose powder, 18 g of ammonium oxalate, and 18 g of sodium bicarbonate and grind them evenly, and then transfer them to a tube furnace for calcination. During the calcination, the flow rate of N.sub.2 is 80 mL/min, and the temperature is programmed to rise to 800° C. at a heating rate of 10° C./min for 1 h.

[0035] After the calcination is completed, the obtained black solid is dispersed in 1000 mL of deionized water, fully stirred at room temperature for 24 h, washed with deionized water and suction-filtered until the solution becomes neutral. Then, the obtained black solid material is dried in a vacuum oven at 75° C. for 6 h, and the porous carbon-nitrogen material is obtained without grinding after taking it out.

[0036] Dissolve 0.369 g of CuCl in 15 mL of concentrated hydrochloric acid, add 45 mL of deionized water, and then add 2.0 g of porous carbon-nitrogen material ensuring that the mass fraction of Cu is 10%. After appropriate stirring, the solution is sonicated for 1 h, then the solution is stirred at room temperature for 10 h, and the mixture is rotary evaporated to obtain a black solid.

[0037] The black solid is dried in a vacuum oven at 75° C. for 3 h. After fully grinding, it is transferred to a reduction furnace for calcination. During the calcination, the gas atmosphere is 10% H.sub.2/N.sub.2, and the gas flow rate is 40 mL/min. and the temperature is programmed to rise to 300° C. at a heating rate of 4° C./min for 2 h. After the reduction is completed, the original atmosphere is maintained and it is allowed to cool to room temperature to obtain 10 wt % Cu/NHPC-300-2.

(2) Catalyst Application

[0038] 10 mL of methanol and 0.3 g of the prepared 10 wt % Cu/NHPC-300-2 catalyst are added to a 100 mL autoclave. After replacing the air in the autoclave with CO, 3.6 MPa CO and 0.4 MPa O.sub.2 were charged in turn. After reacting at 120° C. for 0.5 h, it is cooled in a water bath, and the obtained reaction liquid is separated from the solid catalyst to obtain a clear liquid.

(3) Analysis of Results

[0039] The product is analyzed by gas chromatography using ethanol as the internal standard. Analysis results of methanol conversion, space-time yield, and dimethyl carbonate selectivity are as follows:

TABLE-US-00002 Conv. MeOH(%) S.sub.DMC(%) S.sub.DMM(%) STY(g/(g .Math. h)) 12.66 93.75 4.89 17.6

Embodiment 3

(1) Catalyst Preparation

[0040] Weight 6 g of cellulose powder, 18 g of ammonium oxalate, and 18 g of sodium bicarbonate and grind them evenly, and then transfer them to a tube furnace for calcination. During the calcination, the flow rate of N.sub.2 is 80 mL/min, and the temperature is programmed to rise to 800° C. at a heating rate of 10° C./min for 1 h.

[0041] After the calcination is completed, the obtained black solid is dispersed in 1000 mL of deionized water, fully stirred at room temperature for 24 h, washed with deionized water and suction-filtered until the solution becomes neutral. Then, the obtained black solid material is dried in a vacuum oven at 75° C. for 6 h, and the porous carbon-nitrogen material is obtained without grinding after taking it out.

[0042] Dissolve 0.61 g of CuCl in 15 mL of concentrated hydrochloric acid, add 45 mL of deionized water, and then add 2.0 g of NHPC ensuring that the mass fraction of Cu is 15%. After appropriate stirring, the solution is sonicated for 1 h, then the solution is stirred at room temperature for 10 h, and the mixture is rotary evaporated to obtain a black solid.

[0043] The black solid is dried in a vacuum oven at 75° C. for 3 h. After fully grinding, it is transferred to a reduction furnace for calcination. During the calcination, the gas atmosphere is 10% H.sub.2/N.sub.2, and the gas flow rate is 40 mL/min. and the temperature is programmed to rise to 300° C. at a heating rate of 4° C./min for 2 h. After the reduction is completed, the original atmosphere is maintained and it is allowed to cool to room temperature to obtain 15 wt % Cu/NHPC-300-2.

(2) Catalyst Application

[0044] 10 mL of methanol and 0.3 g of the prepared 15 wt % Cu/NHPC-300-2 catalyst are added to a 100 mL autoclave. After replacing the air in the autoclave with CO, 3.6 MPa CO and 0.4 MPa O.sub.2 were charged in turn. After reacting at 120° C. for 0.5 h, it is cooled in a water bath, and the obtained reaction liquid is separated from the solid catalyst to obtain a clear liquid.

(3) Analysis of Results

[0045] The product is analyzed by gas chromatography using ethanol as the internal standard. Analysis results of methanol conversion, space-time yield, and dimethyl carbonate selectivity are as follows:

TABLE-US-00003 Conv. MeOH(%) S.sub.DMC(%) S.sub.DMM(%) STY(g/(g .Math. h)) 11.04 92.63 5.77 16.1

Embodiment 4

(1) Catalyst Preparation

[0046] Weight 6 g of cellulose powder, 18 g of ammonium oxalate, and 18 g of sodium bicarbonate and grind them evenly, and then transfer them to a tube furnace for calcination. During the calcination, the flow rate of N.sub.2 is 80 mL/min, and the temperature is programmed to rise to 800° C. at a heating rate of 10° C./min for 1 h.

[0047] After the calcination is completed, the obtained black solid is dispersed in 1000 mL of deionized water, fully stirred at room temperature for 24 h, washed with deionized water and suction-filtered until the solution becomes neutral. Then, the obtained black solid material is dried in a vacuum oven at 75° C. for 6 h, and the porous carbon-nitrogen material is obtained without grinding after taking it out.

[0048] Dissolve 0.61 g of CuCl in 15 mL of concentrated hydrochloric acid, add 45 mL of deionized water, and then add 2.0 g of NHPC ensuring that the mass fraction of Cu is 15%. After appropriate stirring, the solution is sonicated for 1 h, then the solution is stirred at room temperature for 10 h, and the mixture is rotary evaporated to obtain a black solid.

[0049] The black solid is dried in a vacuum oven at 75° C. for 3 h. After being thoroughly ground, it is transferred to a reduction furnace for calcination. During the calcination, the gas atmosphere is 10% H.sub.2/N.sub.2, and the gas flow rate is 40 mL/min. and the temperature is programmed to rise to 300° C. at a heating rate of 4° C./min for 3 h. After the reduction is completed, the original atmosphere is maintained and it is allowed to cool to room temperature to obtain 15 wt % Cu/NHPC-300-3.

(2) Catalyst Application

[0050] 10 mL of methanol and 0.3 g of the prepared 15 wt % Cu/NHPC-300-3 catalyst are added to a 100 mL autoclave. After replacing the air in the autoclave with CO, 3.6 MPa CO and 0.4 MPa O.sub.2 were charged in turn. After reacting at 120° C. for 0.5 h, it is cooled in a water bath, and the obtained reaction liquid is separated from the solid catalyst to obtain a clear liquid.

(3) Analysis of Results

[0051] The product is analyzed by gas chromatography using ethanol as the internal standard. Analysis results of methanol conversion, space-time yield, and dimethyl carbonate selectivity are as follows:

TABLE-US-00004 Conv. MeOH(%) S.sub.DMC(%) S.sub.DMM(%) STY(g/(g .Math. h)) 10.96 92.32 6.57 14.5

Embodiment 5

(1) Catalyst Preparation

[0052] Weight 6 g of cellulose powder, 18 g of ammonium oxalate, and 18 g of sodium bicarbonate and grind them evenly, and then transfer them to a tube furnace for calcination. During the calcination, the flow rate of N.sub.2 is 80 mL/min, and the temperature is programmed to rise to 800° C. at a heating rate of 10° C./min for 1 h.

[0053] After the calcination is completed, the obtained black solid is dispersed in 1000 mL of deionized water, fully stirred at room temperature for 24 h, washed with deionized water and suction-filtered until the solution becomes neutral. Then, the obtained black solid material is dried in a vacuum oven at 75° C. for 6 h, and the porous carbon-nitrogen material is obtained without grinding after taking it out.

[0054] Dissolve 0.169 g of CuCl in 15 mL of concentrated hydrochloric acid, add 45 mL of deionized water, and then add 2.0 g of NHPC ensuring that the mass fraction of Cu is 5%. After appropriate stirring, the solution is sonicated for 1 h, then the solution is stirred at room temperature for 10 h, and the mixture is rotary evaporated to obtain a black solid.

[0055] The black solid is dried in a vacuum oven at 75° C. for 3 h. After being thoroughly ground, it is transferred to a reduction furnace for calcination. During the calcination, the gas atmosphere is 10% H.sub.2/N.sub.2, and the gas flow rate is 40 mL/min. and the temperature is programmed to rise to 300° C. at a heating rate of 4° C./min for 2 h. After the reduction is completed, the original atmosphere is maintained and it is allowed to cool to room temperature to obtain 5 wt % Cu/NHPC-300-2.

(2) Catalyst Application

[0056] 10 mL of methanol and 0.2 g of the prepared 5 wt % Cu/NHPC-300-2 catalyst are added to a 100 mL autoclave. After replacing the air in the autoclave with CO, 3.6 MPa CO and 0.4 MPa O.sub.2 were charged in turn. After reacting at 120° C. for 0.5 h, it is cooled in a water bath, and the obtained reaction liquid is separated from the solid catalyst to obtain a clear liquid.

(3) Analysis of Results

[0057] The product is analyzed by gas chromatography using ethanol as the internal standard. Analysis results of methanol conversion, space-time yield, and dimethyl carbonate selectivity are as follows:

TABLE-US-00005 Conv. MeOH(%) S.sub.DMC(%) S.sub.DMM(%) STY(g/(g .Math. h)) 10.5 94.82 3.11 22.1

Embodiment 6

(1) Catalyst Preparation

[0058] Weight 6 g of cellulose powder, 18 g of ammonium oxalate, and 18 g of sodium bicarbonate and grind them evenly, and then transfer them to a tube furnace for calcination. During the calcination, the flow rate of N.sub.2 is 80 mL/min, and the temperature is programmed to rise to 800° C. at a heating rate of 10° C./min for 1 h.

[0059] After the calcination is completed, the obtained black solid is dispersed in 1000 mL of deionized water, fully stirred at room temperature for 24 h, washed with deionized water and suction-filtered until the solution becomes neutral. Then, the obtained black solid material is dried in a vacuum oven at 75° C. for 6 h, and the NHPC is obtained without grinding after taking it out.

[0060] Dissolve 0.8698 g of Cu(NO.sub.3).sub.2.Math.H.sub.2O in 60 mL of deionized water, and then add 2.0 g of NHPC ensuring that the mass fraction of Cu is 10%. After appropriate stirring, the solution is sonicated for 1 h, then the solution is stirred at room temperature for 10 h, and the mixture is rotary evaporated to obtain a black solid.

[0061] The black solid is dried in a vacuum oven at 75° C. for 3 h. After being thoroughly ground, it is transferred to a reduction furnace for calcination. During the calcination, the gas atmosphere is N.sub.2 the gas flow rate is 100 mL/min, and the temperature is programmed to rise to 400° C. at a heating rate of 4° C./min for 2 h. After the calcination is completed, the original atmosphere is maintained and it is allowed to cool to room temperature to obtain 10 wt % CuO/NHPC-400-2.

(2) Catalyst Application

[0062] 10 mL of methanol and 0.3 g of the prepared 10 wt % CuO/NHPC-400-2 catalyst are added to a 100 mL autoclave. After replacing the air in the autoclave with CO, 3.6 MPa CO and 0.4 MPa O.sub.2 were charged in turn. After reacting at 120° C. for 0.5 h, it is cooled in a water bath, and the obtained reaction liquid is separated from the solid catalyst to obtain a clear liquid.

(3) Analysis of Results

[0063] The product is analyzed by gas chromatography using ethanol as the internal standard. Analysis results of methanol conversion, space-time yield, and dimethyl carbonate selectivity are as follows:

TABLE-US-00006 Conv. MeOH(%) S.sub.DMC(%) S.sub.DMM(%) STY(g/(g .Math. h)) 10.81 95.36 2.22 15.3

[0064] From the results in the above examples 1-6, it can be concluded that the copper-based catalyst supported by a porous carbon-nitrogen material provided by the present disclosure catalyzes the oxidative carbonylation of methanol to synthesize dimethyl carbonate with a space-time yield of up to 22.1 g/(g h). In the present disclosure, the conversion rate of methanol and the selectivity of dimethyl carbonate can be adjusted by adjusting the loading amount of active components, the calcination time of the catalyst, and the amount of the catalyst. The prepared catalyst of the present disclosure can be separated from dimethyl carbonate through a simple separation method.

[0065] The above description of the disclosed embodiments enables any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined in this disclosure may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Thus, the present disclosure is not intended to be limited to the embodiments of the present disclosure shown, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.