Application and process of a catalyst in the decarbonylation of oxalate to carbonate

Abstract

This invention relates to the application and process of a catalyst in the decarbonylation of oxalate to carbonate. The catalyst consists of an active element M, an active auxiliary agent N, and a support. Oxalate, after preheating, vaporization, and superheating, undergoes a decomposition reaction in the catalyst of this invention to produce carbonate. The reaction gas is cooled and then separated into gas and liquid phases. The liquid is then separated and purified to obtain the product carbonate. This invention solves the problems of harsh reaction conditions, difficult product separation, low catalyst activity, and easy deactivation in existing technologies, thereby increasing the economic efficiency of the entire coal-based ethylene glycol process and enhancing industry competitiveness.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to the application of a catalyst in the decarbonylation of oxalate to carbonate and its process. Background Technology

[0002] Dimethyl carbonate (DMC), with its active chemical properties, excellent physical properties, and non-toxic, readily biodegradable characteristics, is a novel, low-pollution, environmentally friendly, and green basic chemical raw material. It is widely used in the chemical industry as a solvent, gasoline additive, lithium-ion battery electrolyte, and reagent for carbonylation, methylation, and carbonyl methoxylation. Currently, there are many DMC production processes, mainly including the phosgene method, alcohol oxidation carbonylation method, transesterification method, urea alcoholysis method, direct synthesis from carbon dioxide and alcohols, and the dimethyl oxalate decarbonylation method. Since dimethyl oxalate originates from coal chemical industry and its raw material sources are abundant, the decarbonylation of dimethyl oxalate to prepare dimethyl carbonate is a promising industrial method.

[0003] As early as the 1990s, Japan's Ube Corporation began using alkali metals as catalysts for the decarbonylation of dimethyl oxalate (DMO) to prepare DMC. Although the initial DMC yield was high, the catalyst lifetime was very short. In recent years, research on the decarbonylation of DMO to prepare DMC, conducted by companies such as Hualu Hengsheng and Sinopec, has mainly focused on liquid-phase DMO decarbonylation. However, separating the catalyst and product in liquid-phase decarbonylation technology is difficult, and the catalyst lifetime needs to be improved. Summary of the Invention

[0004] The purpose of this invention is to provide an application of a catalyst in the decarbonylation of oxalate to carbonate and its process, in order to solve the problems of harsh reaction conditions, difficult product separation, low catalyst activity, and easy deactivation in the existing oxalate decarbonylation to carbonate technology.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] An application of a catalyst in the decarbonylation of oxalate to carbonate, the catalyst being composed of an active element M, an active auxiliary agent N, and a support;

[0007] The active element M is selected from one or more of Ru, Rh, Pd, Ni, Ag, Re, Ir, Pt, and Au, preferably Pd, Ru, and Ir;

[0008] The active additive N is selected from one or more of Li, Na, K, Ca, Mg, Cu, Zn, Rb, Ba, Sr, and Cs, preferably K, Ba, and Sr;

[0009] The carrier is selected from one or more of activated carbon, molecular sieve, Al2O3, and SiO2, preferably activated carbon or molecular sieve;

[0010] Based on carrier mass, the mass percentage of M is 0.01%-3.0%; the mass percentage of N is 0.01%-20%.

[0011] Preferably, the mass percentage of M is 0.01%-1.0% and the mass percentage of N is 0.5%-20% based on the carrier mass.

[0012] The catalyst used in this invention is a bifunctional catalyst, which solves the problem of easy carbon deposition in single alkali metal catalysts. The addition of the active component can inhibit carbon deposition on the catalyst surface and extend the catalyst life. In addition, the addition of the alkali metal active agent can enable the active component to gain electrons from the alkali metal active agent, increasing the proportion of zero-valence elements in the active component, thereby increasing the activity and selectivity of the catalyst.

[0013] Preferably, the catalyst is prepared by the following method:

[0014] (1) Weigh the precursor of M according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution;

[0015] (2) Weigh the precursor of N according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution;

[0016] (3) Weigh the carrier according to the mixing ratio;

[0017] (4) The solutions from steps (1) and (2) are co-impregnated or impregnated onto the carrier in equal volumes in steps, and then dried and calcined to obtain the desired catalyst.

[0018] Preferably, the mass percentage of ethanol in the mixture in steps (1) and (2) is 5%-25%; the drying temperature in step (4) is 80-120℃; and the calcination temperature is 400-600℃.

[0019] A process for the decarbonylation of oxalate to carbonate involves a catalytic reaction using the aforementioned catalyst. The oxalate-containing material is mixed with a carrier gas, and the resulting mixture is fed into a decarbonylation reactor containing the catalyst for further reaction. The resulting stream is then separated and purified to obtain high-purity carbonate.

[0020] In a preferred embodiment, the process for decarbonylating oxalate to carbonate specifically includes the following steps:

[0021] (1) The oxalate-containing material S1 is pressurized by a pump and mixed with the carrier gas S2. The resulting mixture S3 enters the decarbonylation reactor B2 for reaction, and the reaction yields the stream S4.

[0022] (2) The material S4 exchanges heat with the oxalate-containing material S1 and enters the gas-liquid separator B3 for gas-liquid separation. The top gas phase component S5 is mixed with the carrier gas S2, and the bottom liquid phase component S6 enters the distillation column B4 for distillation.

[0023] (3) The bottom component S7 of the distillation column B4 is mixed with the oxalate-containing material S1, the top component S8 enters the distillation column B5 for distillation, the bottom component S10 of the distillation column B5 is used to produce high-purity carbonate product, and the top component S9 of the distillation column B5 is further separated or recycled upstream to be mixed with the oxalate-containing material S1.

[0024] Preferably, a preheating mixer B1 is installed upstream of the decarbonylation reactor B2. The mixture S3 is preheated before entering the decarbonylation reactor B2. The preheating mixer B1 preheats the mixture S3 to 150-300°C. If the preheating temperature is too high, a decomposition reaction may occur prematurely, resulting in carbon buildup. If the temperature is too low, the material entering the decarbonylation reactor cannot be effectively preheated, leading to uneven heating temperature.

[0025] When the oxalate-containing material S1 does not contain dimethyl oxalate, the top component S9 of the distillation column B5 is mixed with the material S1 and then circulated to the preheating mixer B1.

[0026] When the oxalate-containing material S1 contains dimethyl oxalate, a distillation column B6 is set up after distillation column B5. The top component S9 of distillation column B5 enters distillation column B6 for distillation. The top component S11 (azeotrope of dimethyl carbonate and methanol) of distillation column B6 is returned to distillation column B5 for recycling distillation. The bottom component S12 (methanol) of distillation column B6 is mixed with material S1 and then recycled to preheating mixer B1.

[0027] Preferably, the oxalate ester includes one or more of dimethyl oxalate, diethyl oxalate, and diphenyl oxalate; the material S1 is pure oxalate molten material or a methanol solution containing oxalate ester; and the carrier gas S2 includes one or more of nitrogen, carbon monoxide, and hydrogen.

[0028] Preferably, the temperature of the decarbonylation reactor B2 is 200-600℃, the pressure is 0.1-5MPa, and the liquid hourly space velocity is 0.1-3.0h. -1 The gas-liquid ratio is 200-25000. The S4 stream obtained after the reaction mainly contains carrier gas, carbon monoxide and carbonate. The temperature of the S4 material after heat exchange is ≥164℃.

[0029] Preferably, the temperature of the gas-liquid separator B3 is 5-10℃;

[0030] The pressure of the distillation column B4 is 0-0.5 bar, and the reboiler temperature is 50-120℃;

[0031] The pressure of the distillation column B5 is 1.0-2.0 MPa, and the reboiler temperature is 100-220℃;

[0032] The pressure of the distillation column B6 is 0-1.0 MPa, and the bottom temperature is 50-150℃.

[0033] Preferably, the decarbonylation reactor B2 is a tubular reactor, and one or more decarbonylation reactors B2' are connected in series after the decarbonylation reactor B2.

[0034] Preferably, the diameter of the decarbonylation reactor B2' is 0.2-0.8 times that of the decarbonylation reactor B2, the height is 0.1-0.25 times that of the decarbonylation reactor B2, the temperature of the decarbonylation reactor B2' is 170-200℃, and the pressure is 0.1-5MPa.

[0035] Using the method of this invention, dimethyl oxalate is decarbonylated to dimethyl carbonate, with a dimethyl oxalate conversion rate of 50%-98% and a carbonate selectivity of 60%-95%. The catalyst lifetime was tested for stability over 200-4000 hours, and no significant decrease in activity was observed.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1) This invention uses a fixed-bed reactor. Oxalate (such as DMO) is preheated and vaporized, and then reacted on a special catalyst to produce carbonate (such as DMC). The reaction gas is cooled and then separated into gas and liquid. The liquid is separated and purified to obtain the product (such as DMC). This invention solves the problems of harsh reaction conditions, difficult product separation, low catalyst activity, and easy deactivation in the prior art.

[0038] 2) This invention employs a bifunctional catalyst, which solves the problem of easy carbon deposition in single alkali metal catalysts. The addition of the active component can inhibit carbon deposition on the catalyst surface and extend the catalyst life. In addition, the addition of the alkali metal active agent can enable the active component to gain electrons from the alkali metal active agent, increasing the proportion of zero-valence elements in the active component, thereby increasing the activity and selectivity of the catalyst. Attached Figure Description

[0039] Figure 1 This is a process flow diagram of oxalate decarbonylation to carbonate in one embodiment of the present invention;

[0040] Figure 2 This is a process flow diagram of oxalate decarbonylation to carbonate in another embodiment of the present invention. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0042] A process for the decarbonylation of oxalate to carbonate utilizes the following catalyst for the catalytic reaction.

[0043] The catalyst comprises an active element M, an active promoter N, and a support. The active element M is selected from one or more of Ru, Rh, Pd, Ni, Ag, Re, Ir, Pt, and Au; the active promoter N is selected from one or more of Li, Na, K, Ca, Mg, Cu, Zn, Rb, Ba, Sr, and Cs; the support is selected from one or more of activated carbon, molecular sieve, Al2O3, and SiO2; the mass percentage of M is 0.01%-3.0% based on the mass of the support; the mass percentage of N is 0.01%-20%, preferably, the mass percentage of M is 0.01%-1.0%; and the mass percentage of N is 0.5%-20%.

[0044] In a preferred embodiment, the active element M is selected from Pd, Ru, and Ir; the active additive N is selected from K, Ba, and Sr; and the carrier is selected from activated carbon and molecular sieve.

[0045] The catalyst was prepared by the following method:

[0046] (1) Weigh the precursor of M according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution;

[0047] (2) Weigh the precursor of N according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution;

[0048] (3) Weigh the carrier according to the mixing ratio;

[0049] (4) The solutions from steps (1) and (2) are co-impregnated or impregnated onto the carrier in equal volumes in steps, and then dried and calcined to obtain the desired catalyst.

[0050] In steps (1) and (2), the precursors of M and N are their soluble salts, and the mass percentage of ethanol is 5%-25%; the drying temperature in step (4) is 80-120℃, and the calcination temperature is 400-600℃.

[0051] The specific steps of the process for decarbonylating oxalate to carbonate are as follows. Figure 1 Process flow diagram:

[0052] (1) The oxalate-containing material S1 is pressurized by a pump and mixed with carrier gas S2. The mixture S3 formed after being preheated by preheating mixer B1 enters decarbonylation reactor B2 for reaction. After the reaction, the material S4 is obtained.

[0053] (2) Material S4 exchanges heat with oxalate-containing material S1 and enters gas-liquid separator B3 for gas-liquid separation. The top gas phase material S5 is mixed with carrier gas S2 and then enters preheating mixer B1. The bottom liquid phase material S6 enters distillation column B4 for distillation.

[0054] (3) The bottom component S7 of the distillation column B4 is mixed with the oxalate-containing material S1 and returned to the preheating mixer B1. The top component S8 enters the distillation column B5 for distillation. The bottom component S10 of the distillation column B5 is used to collect high-purity carbonate and enter the product tank. The top component S9 of the distillation column B5 is further separated or recycled to the preheating mixer B1.

[0055] When the oxalate-containing material S1 does not contain dimethyl oxalate, the top component S9 of the distillation column B5 is mixed with the material S1 and then circulated to the preheating mixer B1.

[0056] When the oxalate-containing material S1 contains dimethyl oxalate, a distillation column B6 is set up after distillation column B5. The top component S9 of distillation column B5 enters distillation column B6 for distillation. The top stream S11 (azeotrope of dimethyl carbonate and methanol) of distillation column B6 is returned to distillation column B5 for recycling distillation. The bottom stream S12 (methanol) of distillation column B6 is mixed with material S1 and then recycled to preheat mixer B1.

[0057] In step (1), the oxalate ester includes one or more of dimethyl oxalate, diethyl oxalate, and diphenyl oxalate; material S1 is pure oxalate melt or a methanol solution containing oxalate; carrier gas S2 includes one or more of nitrogen, carbon monoxide, and hydrogen; preheating mixer B1 preheats the mixture S3 to 150-300℃; the temperature of decarbonylation reactor B2 is 200-600℃, the pressure is 0.1-5MPa, and the liquid hourly space velocity is 0.1-3.0h. -1 The gas-liquid ratio is 200-25000. The S4 stream obtained after the reaction mainly contains carrier gas, carbon monoxide and carbonate. The temperature of the S4 material after heat exchange is ≥164℃.

[0058] In steps (2) and (3), the temperature of gas-liquid separator B3 is 5-10℃; the pressure of distillation column B4 is 0-0.5 bar, and the temperature of the column bottom is 50-120℃; the pressure of distillation column B5 is 1.0-2.0 MPa, and the temperature of the column bottom is 100-220℃; the distillation pressure of distillation column B6 is 0-1.0 MPa, and the temperature of the column bottom is 50-150℃.

[0059] In a preferred embodiment, the decarbonylation reactor B2 is a tubular reactor, and one or more smaller decarbonylation reactors B2' are connected in series after the decarbonylation reactor B2, such as... Figure 2 As shown, a B2' is connected in series after the decarbonylation reactor B2. The diameter of the decarbonylation reactor B2' is 0.2-0.8 times that of the decarbonylation reactor B2, the height is 0.1-0.25 times that of the decarbonylation reactor B2, the temperature is 170-200℃, and the pressure is 0.1-5MPa.

[0060] It should be noted that the "pressure" mentioned in this invention refers to "absolute pressure".

[0061] The following are specific examples.

[0062] Preparation of catalysts for decarbonylation of oxalate to carbonate

[0063] Examples A1 to A20

[0064] The catalyst was prepared by the following method:

[0065] (1) Weigh the precursor of M (e.g., Ni(NO3)2, AgNO3, Pd(NO3)2, ruthenium nitrate) according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution, wherein the mass percentage of ethanol in the mixture is 5%-25%;

[0066] (2) Weigh the precursors of N (e.g., Ca(NO3)2, Mg(NO3)2, KNO3, Ba(NO3)2, Sr(NO3)2) according to the ratio and dissolve them in a mixture of deionized water and ethanol to form a solution, wherein the mass percentage of ethanol in the mixture is 5%-25%.

[0067] (3) Weigh the carrier (e.g., SiO2, activated carbon, molecular sieve) according to the ratio;

[0068] (4) Mix the solutions obtained in steps (1) and (2), and impregnate them onto the carrier in equal volumes or in steps. Filter and wash the carrier, dry it at 80-120℃ for 2-10 hours, and then calcine it at 400-600℃ for 1-6 hours to obtain the catalyst.

[0069] For specific composition and process parameters, please refer to Table 1.

[0070] Comparative Examples 1 to 3

[0071] Compared with Example A11, Comparative Example 1 did not add any active elements, but all other steps were the same.

[0072] Comparative Example 2 is the same as Example A2, except that no active element is added.

[0073] Compared with Example A8, Comparative Example 3 did not add any active elements, but all other steps were the same.

[0074] For specific composition and process parameters, please refer to Table 1.

[0075] Table 1. Specific composition of Examples A1-A18 and Comparative Examples 1-3

[0076]

[0077]

[0078] The catalysts prepared in the examples and comparative examples were used in the process of decarbonylation of oxalate to carbonate.

[0079] Application Example B1

[0080] The catalyst prepared in the examples was used in the process of decarbonylating dimethyl oxalate to dimethyl carbonate, employing methods such as... Figure 1 The process parameters for each component are detailed in Table 2. The conversion rate of DMO, the selectivity of DMC, and the stability of each embodiment and comparative example were tested; the specific results are detailed in Table 3.

[0081] Table 2 Figure 1 Process parameters of each component

[0082]

[0083]

[0084] Table 3. DMO conversion rate, DMC selectivity, and stability tests for each example and comparative example.

[0085] name DMO conversion rate / % DMC Selectivity / % Stability test / h Catalyst A1 90 85 3000 Catalyst A2 70 95 500 Catalyst A3 90 80 2500 Catalyst A4 60 82 500 Catalyst A5 50 61 200 Catalyst A6 52 60 300 Catalyst A7 50 60 400 Catalyst A8 70 70 1500 Catalyst A9 95 80 2500 Catalyst A10 60 60 500 Catalyst A11 95 90 4000 Catalyst A12 98 85 4000 Catalyst A13 90 60 1000 Catalyst A14 80 83 3000 Catalyst A15 80 90 1500 Catalyst A16 85 70 1000 Catalyst A17 85 80 2000 Catalyst A18 70 74 1000 catalyst a 40 40 30 catalyst b 10 30 20 catalyst c 30 37 40

[0086] The results show that the catalyst in this embodiment has high activity and high selectivity, with significantly improved DMO conversion and DMC selectivity compared to the comparative example. Furthermore, the catalyst in this embodiment can effectively extend catalyst lifetime to 4000 hours.

[0087] Application Example B2

[0088] The catalyst prepared in the examples was used in the process of decarbonylating dimethyl oxalate to dimethyl carbonate, employing methods such as... Figure 2 The process parameters for each component are detailed in Table 4. The conversion rates of DMO and DMC in each embodiment and comparative example were tested, and the specific results are detailed in Table 5.

[0089] Table 4 Figure 2 Process parameters of each component

[0090]

[0091] Table 5. DMO, conversion rate, and DMC selectivity for each example and comparative example.

[0092]

[0093]

[0094] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. The application of a catalyst in the decarbonylation of oxalate to carbonate, characterized in that, The catalyst is composed of active element M, active auxiliary agent N, and support; The active element M is selected from one or more of Ru, Rh, Pd, Ni, Ag, Re, Ir, Pt, and Au; The active additive N is selected from one or more of Li, Na, K, Ca, Mg, Cu, Rb, Ba, Sr, and Cs; The carrier is selected from one or more of activated carbon, Al2O3, and SiO2; Based on carrier mass, the mass percentage of M is 0.01%-3.0%; the mass percentage of N is 0.01%-20%. The catalyst was prepared by the following method: (1) Weigh the precursor of M according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution; (2) Weigh the precursor of N according to the ratio and dissolve it in a mixture of deionized water and ethanol to form a solution; (3) Weigh the carrier according to the mixing ratio; (4) The solutions from steps (1) and (2) are co-impregnated or impregnated onto the carrier in equal volumes in steps, dried and calcined to obtain the desired catalyst, wherein the calcination temperature is 400-600℃; The oxalate ester includes one or both of dimethyl oxalate and diethyl oxalate.

2. The application of the catalyst according to claim 1 in the decarbonylation of oxalate to carbonate, characterized in that, The mass percentage of ethanol in the mixture in steps (1) and (2) is 5%-25%; the drying temperature in step (4) is 80-120℃ and the calcination temperature is 400-600℃.

3. A process for the decarbonylation of oxalate to carbonate, characterized in that, The catalyst described in claim 1 or 2 is used to carry out a catalytic reaction. The oxalate-containing material is mixed with a carrier gas, and the resulting mixture is fed into a decarbonylation reactor containing the catalyst for reaction. The resulting stream is then separated and purified to obtain high-purity carbonate. The oxalate ester includes one or both of dimethyl oxalate and diethyl oxalate.

4. The process for decarbonylating oxalate to carbonate according to claim 3, characterized in that, Specifically, the following steps are included: (1) The oxalate-containing material S1 is pressurized by a pump and mixed with the carrier gas S2. The resulting mixture S3 enters the decarbonylation reactor B2 for reaction, and the reaction yields the stream S4. (2) The material S4 and the oxalate-containing material S1 exchange heat and enter the gas-liquid separator B3 for gas-liquid separation. The top gas phase component S5 is mixed with the carrier gas S2, and the bottom liquid phase component S6 enters the distillation column B4 for distillation. (3) The bottom component S7 of the distillation column B4 is mixed with the oxalate-containing material S1, the top component S8 enters the distillation column B5 for distillation, the bottom component S10 of the distillation column B5 is used to produce high-purity carbonate product, and the top component S9 of the distillation column B5 is further separated or recycled upstream to be mixed with the oxalate-containing material S1.

5. The process for decarbonylating oxalate to carbonate according to claim 4, characterized in that, A preheating mixer B1 is installed upstream of the decarbonylation reactor B2. The mixture S3 is preheated before entering the decarbonylation reactor B2. The preheating mixer B1 preheats the mixture S3 to 150-300°C.

6. The process for decarbonylating oxalate to carbonate according to claim 5, characterized in that, When the oxalate-containing material S1 does not contain dimethyl oxalate, the top component S9 of the distillation column B5 is mixed with the material S1 and then recycled to the preheating mixer B1. When the oxalate-containing material S1 contains dimethyl oxalate, a distillation column B6 is set after distillation column B5. The top component S9 of distillation column B5 enters distillation column B6 for distillation, and the top component S11 of distillation column B6 is returned to distillation column B5 for recycling distillation. The bottom component S12 of distillation column B6 is mixed with material S1 and then recycled to the preheating mixer B1.

7. The process for decarbonylating oxalate to carbonate according to claim 4, characterized in that, The decarbonylation reactor B2 operates at a temperature of 200-600℃, a pressure of 0.1-5 MPa, and a liquid hourly space velocity of 0.1-3.0 h⁻¹. -1 The gas-liquid ratio is 200-25000.

8. The process for decarbonylating oxalate to carbonate according to claim 6, characterized in that, The temperature of the gas-liquid separator B3 is 5-10℃; The pressure of the distillation column B4 is 0-0.5 bar, and the reboiler temperature is 50-120℃; The pressure of the distillation column B5 is 1.0-2.0 MPa, and the reboiler temperature is 100-220℃; The pressure of the distillation column B6 is 0-1.0 MPa, and the temperature of the column bottom is 50-150℃.

9. A process for the decarbonylation of oxalate to carbonate according to any one of claims 5-8, characterized in that, The decarbonylation reactor B2 is a tubular reactor, and one or more decarbonylation reactors B2' are connected in series after the decarbonylation reactor B2. The diameter of the decarbonylation reactor B2' is 0.2-0.8 times that of the decarbonylation reactor B2, and the height is 0.1-0.25 times that of the decarbonylation reactor B2. The temperature of the decarbonylation reactor B2' is 170-200℃, and the pressure is 0.1-5MPa.

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