A method for preparing 1,2-dichloroethane

Abstract

This application discloses a method for preparing 1,2-dichloroethane. The method includes reacting a feedstock containing ethylene glycol and / or ethylene glycol ether derivatives and hydrogen chloride in a reactor under nitrogen-modified catalyst conditions to obtain 1,2-dichloroethane. This method can efficiently catalyze the conversion of ethylene glycol and its ether derivatives, achieving a high yield of dichloroethane, with a feedstock conversion rate exceeding 76% and a dichloroethane yield exceeding 71%. It expands the downstream product potential of ethylene glycol and its ether derivatives, showing excellent industrialization prospects and significant economic benefits.

Description

Technical Field

[0001] This application relates to a method for preparing dichloroethane, belonging to the field of dichloroethane preparation and synthesis. Background Technology

[0002] Dichloroethane is an important raw material for the preparation of vinyl chloride monomer, which is mainly used in the production of polyvinyl chloride. Dichloroethane is also commonly used as a solvent in chemical processes. Currently, dichloroethane is mainly prepared through the chlorination of ethylene (using petroleum as a raw material).

[0003] With the rapid development of coal chemical industry, coal-based ethylene glycol now has a significant cost advantage over ethylene glycol production using ethylene as a raw material. Furthermore, methyl methoxyacetate, an important coal chemical intermediate, has attracted widespread attention. It can be further hydrogenated to produce ethylene glycol monomethyl ether. Developing methods for producing dichloroethane from ethylene glycol and its ether derivatives not only reduces the high dependence on petroleum in the traditional ethylene-to-vinyl chloride production route but also expands the downstream products of ethylene glycol and its ether derivatives. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of current technologies by providing a method for producing 1,2-dichloroethane from ethylene glycol and its ether derivatives. This method involves reacting a feedstock containing ethylene glycol and its ether derivatives, along with hydrogen chloride, in a reactor under nitrogen-modified catalyst conditions to obtain the product 1,2-dichloroethane. This method can efficiently catalyze the conversion of ethylene glycol and its ether derivatives, achieving a high yield of dichloroethane.

[0005] A method for preparing 1,2-dichloroethane, the method comprising:

[0006] A feedstock containing ethylene glycol and / or ethylene glycol ether derivatives and hydrogen chloride is reacted in a reactor under nitrogen-modified catalyst conditions to yield 1,2-dichloroethane.

[0007] Optionally, in the nitrogen-modified catalyst, the modified material is selected from at least one of porous silica gel, porous carbon, all-silica or high-silica molecular sieves.

[0008] Optionally, the all-silica or high-silica molecular sieve includes at least one of MCM-41, SBA-15, silicate-1, ZSM-5, Beta, and mordenite.

[0009] The high-silicon molecular sieve is SiO2 / Al2O3. 50 molecular sieve.

[0010] Optionally, the porous carbon is selected from at least one of carbon molecular sieves, mesoporous carbon, and activated carbon.

[0011] Optionally, the nitrogen in the nitrogen-modified catalyst has a nitrogen mass fraction of 1 wt% to 15 wt%.

[0012] Optionally, the mass fraction of nitrogen in the nitrogen-modified catalyst is independently selected from any value or a range between 1 wt%, 2 wt%, 5 wt%, 7 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, and 15 wt%.

[0013] Optionally, the preparation method of the nitrogen-modified catalyst includes the following steps:

[0014] The material to be modified is impregnated in a solution containing nitrogen compounds and then heat-treated in an inactive gas to obtain a nitrogen-modified catalyst.

[0015] Optionally, porous silica gel, porous carbon, all-silica or high-silica molecular sieves are impregnated in a solution containing nitrogen compounds and then heat-treated in an inactive gas to obtain a nitrogen-modified catalyst.

[0016] Optionally, the heat treatment temperature is 200~600℃, and the heat treatment time is 2~24h.

[0017] Optionally, the inactive gas is selected from at least one of nitrogen and inert gases.

[0018] Optionally, the temperature of the heat treatment is independently selected from any value or a range between 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, and 600°C.

[0019] Optionally, the heat treatment time is independently selected from any value of 2h, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 24h or a range between any two.

[0020] Optionally, the nitrogen-containing compound includes at least one of imidazole hydrochloride, pyridine hydrochloride, triethylamine hydrochloride, pyrrole hydrochloride, and piperidine hydrochloride.

[0021] Optionally, the imidazole hydrochloride includes imidazole hydrochloride, 1-methylimidazolium hydrochloride, 1-ethyl-3-methylimidazolium hydrochloride, 1-butyl-3-methylimidazolium hydrochloride, and 1-hexyl-3-methylimidazolium chloride.

[0022] Optionally, the pyridine hydrochloride includes pyridine hydrochloride, 2-chloromethylpyridine hydrochloride, N-methylpyridine hydrochloride, 2-aminopyridine hydrochloride, 1-butylpyridine hydrochloride, and 1-butyl-4-methylpyridine chloride hydrochloride.

[0023] Optionally, the impregnation method is excessive impregnation.

[0024] Optionally, the concentration of the nitrogen-containing compound solution is 0.1 mol / L to 10 mol / L.

[0025] Optionally, after impregnation, the sample is dried and then heat-treated in an inert gas.

[0026] Optionally, the porous silica gel, porous carbon, all-silica or high-silica molecular sieve is impregnated in a solution containing nitrogen compounds, dried, and then heat-treated in an inactive gas.

[0027] Optionally, the concentration of the nitrogen-containing compound solution is 0.1 mol / L to 10 mol / L.

[0028] Optionally, the drying temperature is 100~200℃, and the drying time is 4~48h.

[0029] Optionally, the concentration of the nitrogen-containing compound solution is independently selected from any value or a range between 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, and 10 mol / L.

[0030] Optionally, the ethylene glycol ether derivative is selected from at least one of ethylene glycol monomethyl ether and ethylene glycol dimethyl ether.

[0031] Optionally, the molar ratio of ethylene glycol and / or ethylene glycol ether derivatives to hydrogen chloride is 1:2 to 50.

[0032] Optionally, the molar ratio of ethylene glycol and / or ethylene glycol ether derivatives to hydrogen chloride is independently selected from any value or a range between 1:2, 1:3, 1:4, 1:5, 1:6, 1:8, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:41, 1:42, 1:43, 1:44, 1:45, 1:46, 1:47, 1:48, 1:49, and 1:50.

[0033] Optionally, when the reactor is a batch reactor, the mass ratio of ethylene glycol and / or ethylene glycol ether derivatives to catalyst is 1:0.01~1;

[0034] Optionally, the mass ratio of the ethylene glycol and / or ethylene glycol ether derivatives to the catalyst is independently selected from any value or a range between 1:0.01, 1:0.05, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, and 1:1.

[0035] Optionally, when the reactor is a fixed-bed reactor, the mass flow rate of the ethylene glycol and / or ethylene glycol ether derivatives is 0.01 g / min to 10 g / min.

[0036] Optionally, the mass flow rate of the ethylene glycol and / or ethylene glycol ether derivatives is independently selected from any value or a range between 0.01 g / min, 0.05 g / min, 0.1 g / min, 0.5 g / min, 1 g / min, 2 g / min, 3 g / min, 4 g / min, 5 g / min, 6 g / min, 7 g / min, 8 g / min, 9 g / min, and 10 g / min.

[0037] Optionally, the reactor is selected from a corrosion-resistant batch reactor or a corrosion-resistant fixed-bed reactor.

[0038] Optionally, the reaction pressure is 0.1~15 MPa;

[0039] Optionally, the reaction pressure is independently selected from any value or a range between any two of 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.5 MPa, 1.0 MPa, 2.0 MPa, 3.0 MPa, 4.0 MPa, 5.0 MPa, 6.0 MPa, 8.0 MPa, 10.0 MPa, 11.0 MPa, 12.0 MPa, 13.0 MPa, 14.0 MPa, and 15.0 MPa.

[0040] Optionally, the reaction temperature is 120~350℃.

[0041] Optionally, the reaction temperature is independently selected from any value or a range between 120°C, 130°C, 140°C, 150°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 310°C, 320°C, 330°C, 340°C, and 350°C.

[0042] Optionally, the reaction contact time between the raw material and the nitrogen-modified catalyst is 0.01 to 5 hours.

[0043] Optionally, the contact time of the reaction is independently selected from any value or a range between 0.01h, 0.05h, 0.1h, 0.2h, 0.5h, 1.0h, 1.2h, 1.5h, 2.0h, 2.5h, 3.0h, 3.5h, 4.0h, 4.5h, and 5.0h.

[0044] As one specific implementation method, the method for preparing 1,2-dichloroethane includes:

[0045] The reactants ethylene glycol and / or ethylene glycol ether derivatives, hydrogen chloride, and nitrogen-modified catalyst are added to a corrosion-resistant high-pressure reactor in a certain proportion. The reactor is then pressurized and heated for a period of time to obtain the reaction product 1,2-dichloroethane and the byproduct 2-chloroethanol.

[0046] The preparation of nitrogen-modified catalysts includes: impregnating porous silica gel, porous carbon, all-silica or high-silica molecular sieves in a solution containing nitrogen compounds of a certain concentration, drying them, and then heat-treating them in an inactive gas.

[0047] The beneficial effects that this application can produce include:

[0048] The method for preparing 1,2-dichloroethane provided in this application catalytically converts ethylene glycol and / or ethylene glycol ether derivatives into 1,2-dichloroethane, with a raw material conversion rate of over 76% and a dichloroethane yield of over 71%. This method expands the downstream products of ethylene glycol and its ether derivatives, and has excellent industrialization prospects and significant economic benefits. Detailed Implementation

[0049] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0050] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially. All testing methods employed were conventional, and all instrument settings were as recommended by the manufacturer.

[0051] The analysis method in the embodiments of this application is as follows:

[0052] In the embodiments of this application, the conversion rate of ethylene glycol and its ether derivatives is calculated in the following manner:

[0053] The peak area of ​​ethylene glycol and its ether derivatives in a standard solution is obtained by preparing the standard solution. The peak area is used as the abscissa and the concentration of ethylene glycol and its ether derivatives is used as the ordinate to obtain a standard curve. The concentration of ethylene glycol and its ether derivatives in the reaction solution after the reaction can then be calculated, and the conversion rate of ethylene glycol and its ether derivatives can be calculated from the concentration.

[0054] In the embodiments of this application, the yield of dichloroethane is calculated in the following manner:

[0055] The peak area of ​​gas chromatography is obtained by preparing a standard solution containing dichloroethane. The peak area is used as the abscissa and the concentration of dichloroethane is used as the ordinate to obtain a standard curve. The concentration of dichloroethane in the reaction solution after the reaction can then be calculated, and the yield of dichloroethane can be calculated from the concentration.

[0056] The gas chromatograph used was an Agilent 7890.

[0057] The reaction contact time in a batch reactor = (mass of catalyst / mass of ethylene glycol and its ether derivatives) reaction time

[0058] Reaction contact time in a fixed-bed reactor = catalyst mass / mass flow rate of ethylene glycol and its ether derivatives

[0059] In the embodiments, the preparation process of the nitrogen-modified catalyst is as follows: the material to be modified is excessively impregnated in a solution containing a nitrogen-containing compound of a certain concentration, dried, and then heat-treated in an inactive gas. See Table 1 for details.

[0060] Example 1

[0061] 5g of ethylene glycol and 29.4g of hydrogen chloride (ethylene glycol:hydrogen chloride molar ratio = 1:10), along with 0.5g of nitrogen-modified catalyst #1, were added to a corrosion-resistant autoclave. The reaction pressure was 1.5 MPa, the reaction temperature was 280℃, and the reaction contact time was 0.1 hours. Gas chromatography analysis showed that the ethylene glycol conversion rate was 90% and the dichloroethane yield was 76%.

[0062] Example 2

[0063] Ethylene glycol monomethyl ether (EDG) and hydrogen chloride were introduced into a corrosion-resistant, high-pressure fixed-bed reactor containing 3g of catalyst #2. The mass flow rate of EG was 0.01g / min, and the molar ratio of EG to hydrogen chloride was 1:4. The reaction pressure was 0.5 MPa, the reaction temperature was 140℃, and the reaction contact time was 5 hours. Gas chromatography analysis showed that the conversion rate of EG was 85%, and the yield of dichloroethane was 80%.

[0064] Example 3

[0065] Ethylene glycol monomethyl ether (EDG) and hydrogen chloride were introduced into a corrosion-resistant, high-pressure fixed-bed reactor containing 6 g of catalyst (No. 3). The mass flow rate of EG was 0.1 g / min, the molar ratio of EG to hydrogen chloride was 1:20, the reaction pressure was 3.5 MPa, the reaction temperature was 250 °C, and the reaction contact time was 1 hour. Gas chromatography analysis showed that the conversion rate of EG was 91% and the yield of dichloroethane was 85%.

[0066] Example 4

[0067] Ethylene glycol and hydrogen chloride were introduced into a corrosion-resistant, high-pressure fixed-bed reactor containing 6g of catalyst #4 (SiO2 / Al2O3=150). The mass flow rate of ethylene glycol was 1g / min, the molar ratio of ethylene glycol to hydrogen chloride was 1:5, the reaction pressure was 1MPa, the reaction temperature was 200℃, and the reaction contact time was 0.1 hours. Gas chromatography analysis showed that the conversion rate of ethylene glycol was 81%, and the yield of dichloroethane was 74%.

[0068] Example 5

[0069] 5g of ethylene glycol monomethyl ether and 119.9g of hydrogen chloride (ethylene glycol:hydrogen chloride molar ratio = 1:50), along with 0.05g of nitrogen-modified catalyst #5 (SiO2 / Al2O3 = 200), were added to a corrosion-resistant autoclave. The reaction pressure was 15 MPa, the reaction temperature was 230℃, and the reaction contact time was 0.01 hours. Gas chromatography analysis showed that the conversion rate of ethylene glycol monomethyl ether was 95%, and the yield of dichloroethane was 90%.

[0070] Example 6

[0071] 5g of ethylene glycol dimethyl ether and 60.7g of hydrogen chloride (ethylene glycol:hydrogen chloride molar ratio = 1:30), along with 5g of nitrogen-modified catalyst (all-silica molecular sieve #6), were added to a corrosion-resistant autoclave. The reaction pressure was 2 MPa, the reaction temperature was 180℃, and the reaction contact time was 3 hours. Gas chromatography analysis showed that the conversion rate of ethylene glycol dimethyl ether was 91%, and the yield of dichloroethane was 88%.

[0072] Example 7

[0073] Ethylene glycol monomethyl ether (EDG) and hydrogen chloride were introduced into a corrosion-resistant, high-pressure fixed-bed reactor containing 6 g of catalyst #7 (SiO2 / Al2O3 = 100). The mass flow rate of EG was 5 g / min, the molar ratio of EG to hydrogen chloride was 1:40, the reaction pressure was 12 MPa, the reaction temperature was 300 °C, and the reaction contact time was 0.02 hours. Gas chromatography analysis showed that the conversion rate of EG was 90% and the yield of dichloroethane was 86%.

[0074] Example 8

[0075] 5g of ethylene glycol and 5.88g of hydrogen chloride (molar ratio of ethylene glycol to hydrogen chloride = 1:2), along with 2g of nitrogen-modified catalyst #8 (SiO2 / Al2O3 = 100), were added to a corrosion-resistant autoclave. The reaction pressure was 0.1 MPa, the reaction temperature was 120℃, and the reaction contact time was 5 hours. Gas chromatography analysis showed that the conversion rate of ethylene glycol dimethyl ether was 76%, and the yield of dichloroethane was 71%.

[0076] Example 9

[0077] Ethylene glycol monomethyl ether (EDG) and hydrogen chloride were introduced into a corrosion-resistant, high-pressure fixed-bed reactor containing 6 g of catalyst #9 (SiO2 / Al2O3=50). The mass flow rate of EG was 10 g / min, the molar ratio of EG to hydrogen chloride was 1:10, the reaction pressure was 10 MPa, the reaction temperature was 350 °C, and the reaction contact time was 0.01 h. Gas chromatography analysis showed that the conversion rate of EG was 91% and the yield of dichloroethane was 87%.

[0078] Table 1. Preparation conditions of nitrogen-modified catalysts

[0079]

[0080] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing 1,2-dichloroethane, characterized in that, The method includes: A feedstock containing ethylene glycol and / or ethylene glycol ether derivatives and hydrogen chloride is reacted in a reactor under nitrogen-modified catalyst conditions to obtain 1,2-dichloroethane. In the nitrogen-modified catalyst, the modified material is selected from at least one of porous silica gel, porous carbon, all-silica or high-silica molecular sieves. The all-silicon or high-silicon molecules are screened from at least one of MCM-41, SBA-15, silicalite-1, ZSM-5, Beta, and mordenite. The high-silicon molecular sieve is SiO2 / Al2O3. 50 molecular sieve; The porous carbon is selected from carbon molecular sieves; In the nitrogen-modified catalyst, the mass fraction of nitrogen is 1wt%~15wt%; The preparation method of the nitrogen-modified catalyst includes the following steps: The material to be modified is impregnated in a solution containing nitrogen compounds and then subjected to heat treatment in an inactive gas to obtain a nitrogen-modified catalyst. The nitrogen-containing compound is selected from at least one of imidazole hydrochloride, pyridine hydrochloride, triethylamine hydrochloride, pyrrole hydrochloride, and piperidine hydrochloride; The ethylene glycol ether derivatives are selected from at least one of ethylene glycol monomethyl ether and ethylene glycol dimethyl ether; The molar ratio of ethylene glycol and / or ethylene glycol ether derivatives to hydrogen chloride is 1:2 to 50; The reaction pressure is 0.1~15 MPa; The reaction temperature is 120~350℃.

2. The method according to claim 1, characterized in that, The heat treatment temperature is 200~600℃, and the heat treatment time is 2~24h; The inactive gas is selected from at least one of nitrogen and inert gases.

3. The method according to claim 1, characterized in that, Imidazole hydrochlorides include imidazole hydrochloride, 1-methylimidazolium hydrochloride, 1-ethyl-3-methylimidazolium hydrochloride, 1-butyl-3-methylimidazolium hydrochloride, and 1-hexyl-3-methylimidazolium chloride. Pyridine hydrochlorides include pyridine hydrochloride, 2-chloromethylpyridine hydrochloride, N-methylpyridine hydrochloride, 2-aminopyridine hydrochloride, 1-butylpyridine hydrochloride, and 1-butyl-4-methylpyridine chloride hydrochloride.

4. The method according to claim 1, characterized in that, The impregnation method is excessive impregnation; The concentration of nitrogen-containing compounds in the solution is 0.1 mol / L to 10 mol / L; After impregnation, the product is dried and then heat-treated in an inert gas. The drying temperature is 100~200℃, and the drying time is 4~48h.

5. The method according to claim 1, characterized in that, When the reactor is a batch reactor, the mass ratio of ethylene glycol and / or ethylene glycol ether derivatives to catalyst is 1:0.01~1; When the reactor is a fixed-bed reactor, the mass flow rate of the ethylene glycol and / or ethylene glycol ether derivatives is 0.01 g / min to 10 g / min.

6. The method according to claim 1, characterized in that, The reactor is selected from either a corrosion-resistant batch reactor or a corrosion-resistant fixed-bed reactor.

7. The method according to claim 1, characterized in that, The reaction contact time between the raw material and the nitrogen-modified catalyst is 0.01 to 5 hours.

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