METHOD FOR PRODUCE A SUPPORTED CARBON CATALYST, SUPPORTED CARBON CATALYST AND ITS USE

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for preparing a supported carbon catalyst, in particular to a method for controlling the formation of carbon deposit on the surface of porous silicon dioxide.BACKGROUND

[0002] Conventionally, porous carbon materials are generally used as catalyst carriers because of their high specific surface area, furthermore they have good thermal stability and are chemically inert, and thus are widely used as supported metal or metal oxide catalysts. More and more studies have shown that a large number of defect sites can be produced on the surface of the carbon material, and at the same time saturated or unsaturated functional groups containing hetero atoms such as oxygen, nitrogen, phosphorus, sulfur or boron are produced by controlling the preparation method or chemical treatment, which bring the carbon material a certain acid-base property and redox ability and thus the porous carbon material itself has a catalytic activity, for example which can be used in the dehydrohalogenation reaction of halogenated alkane, the dehydrogenation to olefin reaction of alkane and ethylbenzene, etc., the hydrolysis reaction of cellulose and interesterification reaction, etc. Considering the case of a heterogeneous catalyst, the reaction occurs only on the surface of the catalyst, and the inside of the porous carbon material skeleton has little influence on the catalytic activity. Therefore, the nitrogen-containing porous carbon catalyst can be made into a supported type, that is, a thin layer of doped carbon material is covered on the inorganic porous material such as silica to prepare a supported carbon catalyst, which can greatly reduce the cost of catalyst.

[0003] Xu S. C. et al. (CrystEngComm, 2013, 15, 1840-1844) disclosed a direct synthesis of graphene on SiO 2 substrates by chemical vapor deposition. Continuous and uniform graphene films were directly grown on SiO 2 substrates using a chemical vapor deposition system with two-temperature zones assembled. The carbon species from the high temperature zone nucleate in the low temperature zone, initiating the growing process of graphene. The films are predominantly single-layer graphene, with a small percentage of the area having a few layers, whose optical transmittance and electrical conductivity can be comparable with transferred metal-catalyzed graphene. This method avoids the need for either a metal catalyst or a complicated and skilled post growth transfer process and favors the application of graphene as a transparent electrode.

[0004] Zhao W. et al. (RSC Adv, 2015, 5, 104071-104078) disclosed a catalytic dehydrochlorination of 1,2-dichloroethane to produce vinyl chloride over N-doped coconut activated carbon. A series of N-doped coconut activated carbon catalysts (N-AC) were prepared using melamine as the nitrogen precursor and their performance for the catalytic dehydrochlorination of 1,2-dichloroethane (1,2-DCE) to produce vinyl chloride monomer (VCM) was assessed. It is indicated that the N-doped catalyst 5 : 10-N-AC exhibits a stable catalytic activity at 250 °C with the 1,2-DCE conversion of 85.1% at 180 h. Through DFT calculations, it is suggested that both pyridinic and pyrrolic nitrogen dopants can adsorb preferentially 1,2-DCE and increase the activity for 1,2-DCE dehydrochlorination at low temperature, in combination with characterizations of BET, Raman, TG, TPD, XPS, etc. In addition, the increase of quaternary nitrogen dopants and coking deposition on the catalyst surface can result in the activity decline. The N-doped activated carbon catalyst provides a promising pathway to produce VCM through a low-temperature energy-saving process of 1,2-DCE catalytic dehydrochlorination.

[0005] Very little carbon deposit can be formed by organics on the surface of relatively pure porous silicon dioxide with less impurity metal ions at a low temperature, so it is very difficult to obtain a certain amount of carbon layer with catalytic activity.SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to overcome the deficiencies of the prior art and to provide a method for preparing a catalyst having carbon doped with other elements on a relatively pure porous silicon dioxide surface with less impurity metal ions.

[0007] The temperature and energy consumption of the chemical vapor deposition reaction can be greatly reduced in this method, and the cost of the catalyst can be effectively reduced.

[0008] A method for preparing a supported carbon catalyst is provided according to an aspect of the present invention, the method comprises at least the following steps: (1) contacting a gas containing an organic silicon source with a silicon oxide-based material to obtain a precursor; (2) contacting the precursor with a gas containing an organic carbon source to obtain the supported carbon catalyst; wherein the organic silicon source in step (1) is least one selected from the group consisting of dichlorodimethylsilane, hexamethyldisiloxane, trimethylchlorosilane , phenyltrichlorosilane, dimethoxydimethylsilane; wherein the silicon oxide-based material in step (1) is porous silicon dioxide; wherein the organic carbon source in step (2) is at least one of a C 1 to C 18 organic compound; and the organic compound contains at least one of nitrogen, oxygen, boron, phosphorus, and sulfur; and optionally or preferably, wherein the organic carbon source in step (2) is at least one selected from the group consisting of nitrile compounds, pyridine compounds, organic phosphine compounds, organoboron compounds, thiophene compounds, phenol compounds, and alcohol compounds.

[0009] Optionally, the gas containing the organic silicon source in step (1) may or may not contain an inactive gas; the inactive gas may be nitrogen or an inert gas, and the inert gas is at least one selected from the group consisting of argon gas, helium gas, and the like.

[0010] Those skilled in the art can select the ratio of the inactive gas to the organic silicon source in the gas containing the organic silicon source according to actual needs.

[0011] Preferably, the volume percentage of the inactive gas in the gas containing the organic silicon source is ≤99.5%.

[0012] Further preferably, in the gas containing the organic silicon source, the volume percentage of the inactive gas is in a range from 10% to 90%.

[0013] Optionally, the gas containing the organic silicon source in step (1) contacts with the silicon oxide-based material at a contact temperature in a range from 100°C to 500 °C for 0.1 hour to 10 hours.

[0014] Preferably, the gas containing the organic silicon source in step (1) contacts with the silicon oxide-based material at a contact temperature in a range from 200°C to 450°C for 0.2 hour to 4 hours.

[0015] Optionally, the weight hourly space velocity of the organic silicon source in step (2) is in a range from 0.01h -1< to 8 h -1< .

[0016] Preferably, the weight hourly space velocity of the organic silicon source in step (2) is in a range from 0.01h -1< to 1 h -1< .

[0017] Optionally, the mass percentage of the silicon oxide-based material in the precursor is in a range from 80 wt% to 98 wt%.

[0018] Optionally, the mass percentage of the silicon oxide-based material in the precursor is in a range from 90 wt% to 97wt%.

[0019] That is, the organic silicon source gas in step (1) is deposited on the surface of the silicon oxide-based material to form a silane, the mass content of silane accounts for 2% to 20% of the mass of the silicon dioxide supported with silane.

[0020] The specific kind of the organic carbon source can be selected by those skilled in the art according to actual needs, and organic compounds which can be vapor deposited can be used as the organic carbon source of the present application in principle.

[0021] Optionally, the gas containing the organic carbon source in step (2) may or may not contain an inactive gas; the inactive gas may be nitrogen or an inert gas, and the inert gas is at least one selected from the group consisting of argon gas, helium gas, and the like.

[0022] Those skilled in the art can select the ratio of the inactive gas to the organic silicon source in the gas containing the organic carbon source according to actual needs.

[0023] Preferably, the volume percentage of the inactive gas in the gas containing the organic carbon source is ≤99.5%.

[0024] Further preferably, in the gas containing the organic carbon source, the volume percentage of the inactive gas is in a range from 10% to 90%.

[0025] Optionally, the precursor in step (2) contacts with the gas containing the organic carbon source at a contact temperature in a range from 500°C to 1000°C for 0.1 hour to 10 hours.

[0026] Preferably, the precursor in step (2) contacts with the gas containing the organic carbon source at a contact temperature in a range from 600°C to 900°C for 0.1 hour to 4 hours.

[0027] Optionally, the weight hourly space velocity of the organic carbon source in step (2) is in a range from 0.01h -1< to 8 h -1< .

[0028] Preferably, the weight hourly space velocity of the organic carbon source in step (2) is in a range from 0.1h -1< to 2 h -1< .

[0029] Optionally, the mass percentage of the silicon oxide-based material in the supported carbon catalyst is in a range from 60 wt% to 95wt%.

[0030] Preferably, the mass percentage of the silicon oxide-based material in the supported carbon catalyst is in a range from 75 wt% to 93wt%.

[0031] That is, the mass content of the vapor deposited carbon is in a range from 5% to 40% based on the mass of the catalyst, preferably 7% to 25%.

[0032] The silane deposited in step (1) will be pyrolyzed to produce radicals at a high temperature, which induce the organics in step (2) to crack to produce a carbon deposit on the surface of the silica gel, and the amount of deposited carbon can be determined by calculating the weight loss after calcination in air for removing the carbon.

[0033] The amount of silane deposited in step (1) can be determined by the weight gain of the silica gel in step (1).

[0034] The overall concept of the invention is based on the following scheme: In step (1), grafting a silane with a hydrocarbonyl group or a substituted hydrocarbonyl group onto the surface of the silica gel, the silane is required to have at least one hydrocarbonyl group or substituted hydrocarbonyl group, and at least one group capable of reacting with the hydroxyl group on the surface of the silica gel such as hydrogen, halogen, alkoxy and the like to graft the silane on the surface of the silica gel.

[0035] In step (2), the hydrocarbonyl group or the substituted hydrocarbonyl group in the silane grafted on the surface of the silica gel is pyrolyzed to produce radicals (organic radical and silicon radical) at a high temperature, which induce the organics added in the step (2) to crack to produce a carbon deposit on the surface of the silica gel,so as to promote the deposition of the organics on the surface of the silica gel at a lower temperature.

[0036] According to still another aspect of the present application, a method for preparing chloroethylene from 1,2-dichloroethane is provided, comprising following steps: (1) contacting a gas containing an organic silicon source with a silicon oxide-based material to obtain a precursor; (2) contacting the precursor with a gas containing an organic carbon source to obtain the supported carbon catalyst; wherein the organic silicon source in step (1) is least one selected from the group consisting of dichlorodimethylsilane, hexamethyldisiloxane, trimethylchlorosilane, phenyltrichlorosilane and dimethoxydimethylsilane; wherein the silicon oxide-based material in step (1) is porous silicon dioxide; wherein the organic carbon source in the step (2) is at least one of a C 1 to C 18 organic compound; the organic compound contains at least one selected from the group consisting of nitrogen, oxygen, boron, phosphorus, and sulfur; and optionally or preferably, wherein the organic carbon source in step (2) is at least one selected from the group consisting of nitrile compounds, pyridine compounds, organic phosphine compounds, organoboron compounds, thiophene compounds, phenol compounds, and alcohol compounds; (3) passing a feed gas containing 1,2-dichloroethane through a fixed bed reactor loaded with the supported carbon catalyst obtained in step (2) to prepare chloroethylene.

[0037] In the present invention: C 1 to C 12 , C 1 to C 5 , C 1 to C 18 , etc. all refer to the number of carbon atoms contained in the group.

[0038] For example, "a C 1 to C 12 hydrocarbyl" means a hydrocarbyl group with 1 to 12 carbon atoms.

[0039] The "hydrocarbyl group" is a group formed by losing any one hydrogen atom from hydrocarbon compound molecule.

[0040] The hydrocarbon compounds include alkane compounds, olefin compounds, alkyne compounds, and aromatic hydrocarbon compounds.

[0041] The "substituted hydrocarbyl group" is a group formed by substituting at least one hydrogen atom of hydrocarbyl group with a substituent.

[0042] The "alkyl group" is a group formed by lossing any one hydrogen atom from alkane compound molecule.

[0043] The alkane compound includes a linear alkane, a branched alkane, a cycloalkane, a branched cycloalkane.

[0044] The "substituted alkyl group" is a group formed by substituting at least one hydrogen atom of alkyl group with a substituent.

[0045] The "hydrocarbyloxy group" means a group formed by losing hydrogen from a hydroxyl group of alcohol compounds.

[0046] The "alkylacyloxy group" means a group formed by losing hydrogen from a carboxy group of carboxylic acid compounds.

[0047] The "hydrocarbyloxy acyl" means a group formed by losing hydrogen from HCOOR a< of formic acid hydrocarbon ester compounds.

[0048] Wherein, Ra is a hydrocarbyl group.

[0049] Preferably, Ra is a C 1 to C 5 alkyl group.

[0050] The "amino group" has a formula of -NR b< 2 , and R b< is hydrogen and / or a hydrocarbyl group.

[0051] Preferably, R b< is hydrogen and / or a C 1 to C 5 alkyl group.

[0052] Advantages of the application include, but are not limited to: (1)the carbon material can be sufficiently supported on the catalyst carrier by firstly grafting the organosilane on the surface of the carrier in the method for preparing a catalyst provided by the present application. (2)the temperature and energy consumption for the chemical vapor deposition reaction of the hetero atom-containing carbon material on the silicon oxide-based material can be greatly reduced and thus the cost of the catalyst can be effectively reduced according to the method for preparing a catalyst provided by the present application. (3)the selectivity to chloroethylene is more than 99% using the catalyst prepared by the method described in the present application in the cracking reaction of 1,2-dichloroethane to produce chloroethylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a photograph of sample 1 #< . Figure 2 is a photograph of sample 2 #< . Figure 3 is a photograph of sample D-1 #< . DETAILED DESCRIPTION OF THE EMBODIMENT

[0054] The method for preparing a supported carbon catalyst comprises the following steps: (1) depositing an organic silicone source gas on a surface of a porous silicon dioxide as a catalyst carrier by a vapor deposition method; (2) introducing an organic gas onto the surface of the porous silicon dioxide treated in the step (1) to vapor-deposit the supported carbon on the surface of the porous silicon dioxide.

[0055] In the examples, the silica gel pellets with a particle diameter of 2mm to 4mm were purchased from Qingdao Ocean Chemical Co., Ltd., and which were colorless and transparent.

[0056] Silica gel powder was purchased from Dongying Yiming New Material Co., Ltd., with a particle diameter of 80 mesh to 120 mesh and a color of white;

[0057] FNG silica gel was purchased from Qingdao Ocean Chemical Co., Ltd., with a particle diameter of 2mm to 4mm and a color of white.Example 1

[0058] The FNG silica gel that washed with hydrochloric acid having a mass concentration of 20% was used as a carrier, the dimethyldichlorosilane was used as an organic silicone source in step (1), and the acetonitrile was used as an organic precursor for vapor-depositing in step (2). (1) 65mL of FNG silica gel was put into a quartz tube, the quartz tube was placed in the tube furnace, a nitrogen gas was introduced as a carrier gas and the temperature was raised to 400 °C, and then the gas path was switched so that the nitrogen gas carrying the vaporized dichlorodimethylsilane entered into the quartz tube by way of a bubbling device. The vapor deposition process was performed for 2 hours to graft organosilane to obtain a precursor.

[0059] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the dichlorodimethylsilane bubbler was 25 °C.

[0060] (2) the gas path was switched so that the nitrogen gas entered into the quartz tube directly not through the bubbling device, and the gas path was switched again after the temperature was raised to 800 °C so that the nitrogen gas carrying vaporized acetonitrile entered into the quartz tube by way of another bubbling device. The chemical vapor deposition process was performed for 2 hours.

[0061] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the acetonitrile bubbler was 65 °C.

[0062] The gas path was switched so that the nitrogen gas entered into the quartz tube directly not through another bubbling device, a nitrogen-containing supported carbon catalyst sample was obtained after natural cooling in nitrogen, and was designated as sample 1 #< .

[0063] The mass ratio of the precursor to FNG silica gel was 1.10:1.

[0064] The mass ratio of sample 1 #< to FNG silica gel was 1.12:1.

[0065] The photograph of sample 1 #< is shown in Figure 1.

[0066] As can be seen from Figure 1, the surface of sample 1 #< appears black, indicating that the carbon material is sufficiently loaded onto the carrier.Example 2

[0067] The silica gel powder was used as a carrier, the hexamethyldisiloxane was used as an organic silicon source in the step (1), and the pyridine was used as an organic precursor for vapor-depositing in step (2). (1) 125mL of silica gel powder was put into a quartz tube, the quartz tube was placed in the tube furnace, a nitrogen gas was introduced as a carrier gas and the temperature was raised to 400 °C, and then the gas path was switched so that the nitrogen gas carrying the vaporized hexamethyldisiloxane entered into the quartz tube by way of a bubbling device. The vapor deposition process was performed for 2 hours to graft organosilane.

[0068] In vapor deposition, the flow rate of the nitrogen gas was 200 mL / min; the temperature of the hexamethyldisiloxane bubbler was 30 °C.

[0069] (2) the gas path was switched so that the nitrogen gas entered into the quartz tube directly not through the bubbling device, and the gas path was switched again after the temperature was raised to 750°C so that the nitrogen gas carrying vaporized pyridine entered into the quartz tube by way of another bubbling device. The chemical vapor deposition process was performed for 2 hours.

[0070] In vapor deposition, the flow rate of the nitrogen gas was 250 mL / min; the temperature of the pyridine bubbler was 90 °C.

[0071] The gas path was switched so that the nitrogen gas entered into the quartz tube directly not through another bubbling device, a nitrogen-containing supported carbon catalyst sample was obtained after natural cooling in nitrogen, and was designated as sample 2 #< .

[0072] The mass ratio of the precursor to the silica gel pellets was 1.08: 1.

[0073] The mass ratio of sample 2 #< to the silica gel pellets was 1.17:1.

[0074] The photograph of sample 2 #< is shown in Figure 2.

[0075] As can be seen from Figure 2, the surface of sample 2 #< appears black, indicating that the carbon material is sufficiently loaded onto the carrier.Example 3

[0076] The silica gel pellets that washed with hydrochloric acid having a mass concentration of 20% were used as a carrier, the trimethylchlorosilane was used as an organic silicone source in step (1), and the triphenylphosphine was used as an organic precursor for vapor-depositing in step (2). (1) 65mL of silica gel pellets were put into a quartz tube, the quartz tube was placed in the tube furnace, an argon gas was introduced as a carrier gas and the temperature was raised to 400 °C, and then the gas path was switched so that the argon gas carrying the vaporized trimethylchlorosilane entered into the quartz tube by way of a bubbling device. The vapor deposition process was performed for 2 hours to graft organosilane.

[0077] In vapor deposition, the flow rate of the argon gas was 100 mL / min; the temperature of the trimethylchlorosilane bubbler was 30 °C.

[0078] (2) the gas path was switched so that the argon gas entered into the quartz tube directly not through the bubbling device, and the gas path was switched again after the temperature was raised to 800°C so that the argon gas carrying vaporized triphenylphosphine entered into the quartz tube by way of another bubbling device. The chemical vapor deposition process was performed for 4 hours.

[0079] In vapor deposition, the flow rate of the argon gas was 100 mL / min; the temperature of the triphenylphosphine bubbler was 280 °C.

[0080] The gas path was switched so that the argon gas entered into the quartz tube directly not through another bubbling device, a phosphorus-containing supported carbon catalyst sample was obtained after natural cooling in argon, and was designated as sample 3 #< .

[0081] The mass ratio of the precursor to the silica gel pellets was 1.10:1.

[0082] The mass ratio of sample 3 #< to the silica gel pellets was 1.06: 1.

[0083] The appearance of sample 3 #< is similar to that of sample 1 #< , and the surface of sample 3 #< appears black, indicating that the carbon material is sufficiently loaded onto the carrier.Example 4

[0084] The silica gel pellets that washed with hydrochloric acid having a mass concentration of 20% were used as a carrier, the phenyltrichlorosilane was used as an organic silicone source in step (1), and the triphenylboron was used as an organic precursor for vapor-depositing in step (2). (1) 65mL of silica gel pellets were put into a quartz tube, the quartz tube was placed in the tube furnace, a nitrogen gas was introduced as a carrier gas and the temperature was raised to 400 °C, and then the gas path was switched so that the nitrogen gas carrying the vaporized phenyltrichlorosilane entered into the quartz tube by way of a bubbling device. The vapor deposition process was performed for 2 hours to graft organosilane.

[0085] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the phenyltrichlorosilane bubbler was 120 °C.

[0086] (2) the gas path was switched so that the nitrogen gas entered into the quartz tube directly not through the bubbling device, and the gas path was switched again after the temperature was raised to 750°C so that the nitrogen gas carrying vaporized triphenylboron entered into the quartz tube by way of another bubbling device. The chemical vapor deposition process was performed for 2 hours.

[0087] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the triphenylboron bubbler was 280 °C.

[0088] The gas path was switched so that the nitrogen gas entered into the quartz tube directly not through another bubbling device, a boron-containing supported carbon catalyst sample was obtained after natural cooling in nitrogen, and was designated as sample 4 #< .

[0089] The mass ratio of the precursor to the silica gel pellets was 1.06: 1.

[0090] The mass ratio of sample 4 #< to the silica gel pellets was 1.07: 1.

[0091] The appearance of sample 4 #< is similar to that of sample 1 #< , and the surface of sample 4 #< appears black, indicating that the carbon material is sufficiently loaded onto the carrier.Example 5

[0092] The silica gel pellets that washed with hydrochloric acid having a mass concentration of 20% were used as a carrier, the dichlorodimethylsilane was used as an organic silicone source in step (1), and the thiophene was used as an organic precursor for vapor-depositing in step (2). (1) 65mL of silica gel pellets were put into a quartz tube, the quartz tube was placed in the tube furnace, a nitrogen gas was introduced as a carrier gas and the temperature was raised to 400 °C, and then the gas path was switched so that the nitrogen gas carrying the vaporized dichlorodimethylsilane entered into the quartz tube by way of a bubbling device. The vapor deposition process was performed for 2 hours to graft organosilane.

[0093] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the dichlorodimethylsilane bubbler was 20 °C.

[0094] (2) the gas path was switched so that the nitrogen gas entered into the quartz tube directly not through the bubbling device, the temperature was raised to 700°C and then the thiophene was input into the quartz tube by charging pump. The chemical vapor deposition process was performed for 0.2 hours.

[0095] In vapor deposition, the flow rate of the nitrogen was 100 mL / min; the flow rate of thiophene was 0.25 mL / min.

[0096] The sulfur-containing supported carbon catalyst sample was obtained after natural cooling in nitrogen, and was designated as sample 5 #< .

[0097] The mass ratio of the precursor to the silica gel pellets was 1.10:1.

[0098] The mass ratio of sample 5 #< to the silica gel pellets was 1.06: 1.

[0099] The appearance of sample 5 #< is similar to that of sample 1 #< , and the surface of sample 5 #< appears black, indicating that the carbon material is sufficiently loaded onto the carrier.Example 6

[0100] The silica gel pellets that washed with hydrochloric acid having a mass concentration of 20% were used as a carrier, the dimethyldimethoxysilane was used as an organic silicone source in step (1), and the phenol was used as an organic precursor for vapor-depositing in step (2). (1) 65mL of silica gel pellets were put into a quartz tube, the quartz tube was placed in the tube furnace, a nitrogen gas was introduced as a carrier gas and the temperature was raised to 400 °C, and then the gas path was switched so that the nitrogen gas carrying the vaporized dichlorodimethylsilane entered into the quartz tube by way of a bubbling device. The vapor deposition process was performed for 2 hours to graft organosilane.

[0101] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the dimethyldimethoxysilane bubbler was 20 °C.

[0102] (2) the gas path was switched so that the nitrogen gas entered into the quartz tube directly not through the bubbling device, and the gas path was switched again after the temperature was raised to 800°C so that the nitrogen gas carrying vaporized phenol entered into the quartz tube by way of another bubbling device. The chemical vapor deposition process was performed for 0.2 hours.

[0103] In vapor deposition, the flow rate of the nitrogen gas was 100 mL / min; the temperature of the phenol bubbler was 130 °C.

[0104] The gas path was switched so that the nitrogen gas entered into the quartz tube directly not through another bubbling device, an oxygen-containing supported carbon catalyst sample was obtained after natural cooling in nitrogen, and was designated as sample 6 #< .

[0105] The mass ratio of the precursor to the silica gel pellets was 1.08: 1.

[0106] The mass ratio of sample 6 #< to the silica gel pellets was 1.05:1.

[0107] The appearance of sample 6 #< is similar to that of sample 1 #< , and the surface of sample 6 #< appears black, indicating that the carbon material is sufficiently loaded onto the carrier.Example 7 Performance test of catalyst

[0108] The samples 1 #< to 6 #< were used as catalysts for testing the catalytic performance in the the cracking reaction of 1,2-dichloroethane for the preparation of chloroethylene. The specific steps and conditions were as follows: 1,2-dichloroethane liquid was preheated and vaporized in the evaporator, and then passed to a fixed bed reactor loaded with the catalyst by a constant flow pump. The reactor temperature was 250 □, the gaseous hourly space velocity (GHSV) of 1,2-dichloroethane was 133 h -1< .

[0109] The reaction results show that the conversion rates of 1,2-dichloroethane are each higher than 15%, and the selectivities to chloroethylene are each more than 99% using samples 1 #< to 6 #< as catalysts in the cracking reaction of 1,2-dichloroethane for the preparation of chloroethylene.

[0110] The conversion rate of 1,2-dichloroethane is 40% and the selectivity to chloroethylene is more than 99% using sample 1 #< as a typical example.Comparative example 1

[0111] Other steps and conditions were the same as that in example 1 except that the vapor phase deposition process for grafting organosilane was not included, specifically: (1) 65mL of FNG silica gel was put into a quartz tube, the quartz tube was placed in the tube furnace, a nitrogen gas was introduced as a carrier gas and the temperature was raised to 800 °C, and then the gas path was switched so that the nitrogen gas carrying the vaporized acetonitrile entered into the quartz tube by way of an acetonitrile bubbler. The vapor deposition process was performed for 2 hours.

[0112] The gas path was switched so that the nitrogen gas entered into the quartz tube directly not through the bubbling device, a sample designated as sample D-1 #< was obtained after natural cooling in nitrogen.

[0113] A sample photograph of the sample of D-1 #< is shown in Figure 3.

[0114] As can be seen from Figure 3, the surface of sample D-1 #< appears very light gray, indicating that the amount of carbon material supported on the surface of the FNG silica gel is extremely small.

[0115] If the silicone source is not grafted in advance, the nitrogen-containing organic materials can hardly be loaded on the silica gel carrier.

[0116] The above are only a few embodiments of the present application, and are not intended to limit the present application in any form. Although the present application is disclosed by the preferred embodiments as above, they are however not used to limit the present application. A slight change or modification utilizing the technical content disclosed above made by the person skilled in art, without departing from the technical solution of the present application, is equivalent to the equivalent embodiment, and falls within the scope of the technical solution.

Claims

1. A method for preparing a supported carbon catalyst, wherein the method comprises: (1) contacting a gas containing an organic silicon source with a silicon oxide-based material to obtain a precursor; (2) contacting the precursor with a gas containing an organic carbon source to obtain the supported carbon catalyst; wherein the organic silicon source in step (1) is least one selected from the group consisting of dichlorodimethylsilane, hexamethyldisiloxane, trimethylchlorosilane, phenyltrichlorosilane and dimethoxydimethylsilane; wherein the silicon oxide-based material in step (1) is porous silicon dioxide; wherein the organic carbon source in the step (2) is at least one of a C1 to C18 organic compound; the organic compound contains at least one selected from the group consisting of nitrogen, oxygen, boron, phosphorus, and sulfur; and optionally or preferably, wherein the organic carbon source in step (2) is at least one selected from the group consisting of nitrile compounds, pyridine compounds, organic phosphine compounds, organoboron compounds, thiophene compounds, phenol compounds, and alcohol compounds.

2. The method according to claim 1, wherein the gas containing the organic silicon source in step (1) contains or does not contain an inactive gas; the inactive gas is at least one selected from the group consisting of nitrogen, argon gas and helium gas.

3. The method according to claim 1, wherein the gas containing the organic silicon source in step (1) contacts with the silicon oxide-based material at a contact temperature in a range from 100°C to 500 °C for 0.1 hour to 10 hours; and optionally or preferably, wherein the gas containing the organic silicon source in step (1) contacts with the silicon oxide-based material at a contact temperature in a range from 200 °C to 450 °C for 0.2 hour to 4 hours.

4. The method according to claim 1, wherein the mass percentage of the silicon oxide-based material in the precursor is in a range from 80 wt% to 98 wt%; and optionally or preferably, wherein the mass percentage of the silicon oxide-based material in the precursor is in a range from 90 wt% to 97wt%.

5. The method according to claim 1, wherein the gas containing the organic carbon source in step (2) contains an inactive gas; the inactive gas is at least one selected from the group consisting of nitrogen, argon gas and helium gas.

6. The method according to claim 1, wherein the precursor in step (2) contacts with the gas containing the organic carbon source at a contact temperature in a range from 500 °C to 1000°C for 0.1 hour to 10 hours; and optionally or preferably, wherein the precursor in step (2) contacts with the gas containing the organic carbon source at a contact temperature in a range from 600 °C to 900°C for 0.1 hour to 4 hours.

7. The method according to claim 1, wherein the mass percentage of the silicon oxide-based material in the supported carbon catalyst is in a range from 60 wt% to 95wt%; and optionally or preferably, wherein the mass percentage of the silicon oxide-based material in the supported carbon catalyst is in a range from 75 wt% to 93wt%.

8. A method for preparing chloroethylene from 1,2-dichloroethane comprising following steps: (1) contacting a gas containing an organic silicon source with a silicon oxide-based material to obtain a precursor; (2) contacting the precursor with a gas containing an organic carbon source to obtain the supported carbon catalyst; wherein the organic silicon source in step (1) is least one selected from the group consisting of dichlorodimethylsilane, hexamethyldisiloxane, trimethylchlorosilane, phenyltrichlorosilane and dimethoxydimethylsilane; wherein the silicon oxide-based material in step (1) is porous silicon dioxide; wherein the organic carbon source in the step (2) is at least one of a C1 to C18 organic compound; the organic compound contains at least one selected from the group consisting of nitrogen, oxygen, boron, phosphorus, and sulfur; and optionally or preferably, wherein the organic carbon source in step (2) is at least one selected from the group consisting of nitrile compounds, pyridine compounds, organic phosphine compounds, organoboron compounds, thiophene compounds, phenol compounds, and alcohol compounds; (3) passing a feed gas containing 1,2-dichloroethane through a fixed bed reactor loaded with the supported carbon catalyst obtained in step (2) to prepare chloroethylene.