A method for preparing vinyl sulfate by continuous oxidation of vinyl sulfite

Abstract

The invention discloses a method for preparing vinyl sulfate by continuously oxidizing vinyl sulfite. In a fixed bed reactor, vinyl sulfite is used as a raw material and hydrogen peroxide is used as an oxidant. Under the condition of continuous introduction of carrier gas at 5-100°C, a high conversion rate of 98% of the raw material and a product selectivity of 88% are achieved. The catalyst is not deactivated after 300 hours of reaction and has good stability. The invention removes the reaction product in time and reduces product hydrolysis by continuously introducing carrier gas into the fixed bed reactor, thereby improving product selectivity. The fixed bed reactor is adopted to solve the problems of complex operation of intermittent reactors, difficult catalyst separation, discontinuous reaction, etc. The method for continuously preparing vinyl sulfate provided by the invention is simple, efficient, and has low energy consumption. The cheap titanium silicon molecular sieve reduces the reaction cost and is easy to industrialize, providing a new route for the efficient and green conversion of vinyl sulfite to prepare vinyl sulfate.

Description

Technical Field

[0001] The invention relates to the fields of chemistry and catalytic science, and relates to a method for preparing vinyl sulfate by continuous reaction in a fixed bed reactor equipped with a solid catalyst, using vinyl sulfite and hydrogen peroxide as raw materials. Background Art

[0002] In recent years, with the rapid development of new energy vehicles around the world, the market demand for lithium-ion power batteries has also increased. Lithium-ion batteries are mainly composed of positive electrode materials, negative electrode materials, electrolytes and separators. Among them, the electrolyte plays an important role in the charge and discharge performance and safety of the battery. Since adding a small amount of film-forming additives to the electrolyte can significantly improve the recycling performance and safety performance of the electrolyte, the research on electrolyte film-forming additives has attracted widespread attention. Electrolyte film-forming additives include fluoroethylene carbonate (FEC), vinylene carbonate (VC), and diethylene sulfate (DTD). Among them, DTD can effectively inhibit the decline in the initial capacity of the battery, increase the initial discharge capacity, reduce battery expansion at high temperatures, reduce capacity attenuation and internal resistance, and DTD can also improve the stability of the graphite negative electrode. In addition, among pharmaceutical intermediates, DTD can be used to synthesize antihypertensive drugs and new dual surfactants. Based on this, green and efficient large-scale synthesis of DTD has attracted more and more attention.

[0003] Literature (Vanhessche KPM, Sharpless KB, Chem. Eur. J. 1997, 3,517-522) reported the use of sulfuryl chloride and ethylene glycol to prepare vinyl sulfate. The raw materials of this method are cheap, but the reaction yield is low, the raw material sulfuryl chloride is highly corrosive, and the three wastes of the reaction cause great environmental pollution, which is not suitable for industrial production. Patent CN111533728A discloses a method for preparing vinyl sulfate by oxidation of vinyl sulfite, which uses ruthenium trichloride as a catalyst and sodium hypochlorite as an oxidant at a low temperature of 5 oC for oxidation reaction. This method has a mature process and a simple flow, and is also the mainstream solution in the industry at present, but the precious metals used are expensive, the homogeneous reaction catalyst is difficult to recover, and the low temperature conditions increase the process energy consumption. Patent CN107973774A and Patent CN108707095A respectively use microchannel reactors, and still use RuCl3 and NaClO systems to achieve the purpose of continuously oxidizing vinyl sulfite to prepare vinyl sulfate, but the homogeneous reaction system still cannot solve the problem of the use of precious metals. Patent CN109422719A uses titanium silicon molecular sieve (TS-1) as a catalyst, 30wt% hydrogen peroxide (H2O2) as an oxidant, and dichloromethane as a solvent to oxidize vinyl sulfite in a jacketed intermittent reactor. This reaction system realizes the multiphase reaction and avoids the use of precious metals. The oxidant H2O2 is also relatively green, but the reaction time in the intermittent reactor is long, the catalyst recycling process is cumbersome, and the yield is only 44%. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for preparing vinyl sulfate by continuous catalytic oxidation using titanium silicon molecular sieves. The use of titanium silicon molecular sieves in fixed bed reactors solves the cumbersome problem of catalyst separation in intermittent reactor reactions. In addition, the fixed bed reactor replaces the traditional kettle reactor, which simplifies the reaction operation and shortens the reaction time. By controlling the carrier gas flow rate, the reaction product is removed from the system in time to avoid further hydrolysis of the product at high temperature, thereby improving the selectivity of the product. This solution is conducive to the green industrial production of vinyl sulfate.

[0005] The technical route adopted by the present invention is: a method for preparing vinyl sulfate by continuously oxidizing vinyl sulfite, which is carried out according to the following steps: using a fixed bed reactor as a reaction site, loading a corresponding catalyst into the bed layer, introducing vinyl sulfite reaction liquid and hydrogen peroxide under the condition of continuously introducing a carrier gas, and continuously preparing vinyl sulfate at a certain temperature.

[0006] The specific steps are as follows:

[0007] (1) Prepare the corresponding concentration of raw material liquid and hydrogen peroxide oxidant, and input them into the preheater at the set temperature according to a certain ratio.

[0008] (2) The liquid in the preheater is transported to a fixed bed reactor with a set temperature and loaded with the corresponding catalyst. The reaction conditions are set as follows: reaction temperature 5~100℃; raw material space velocity 0.1~30 h -1 ; Reaction pressure is 0.1~1.0 MPa; Carrier gas flow rate is 0~500 mL / min.

[0009] (3) The reaction product is stored in a low-temperature static separation tank. Through static separation, the lower oil phase is pumped to a storage tank for subsequent distillation and purification, and the upper water phase is pumped to a wastewater collection section.

[0010] In the above technical scheme, the raw material liquid is an ethylene sulfite solution, and its solvent is selected from one or a mixture of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, dichloromethane and ethylene dichloride.

[0011] In the above technical solution, the molar ratio of vinyl sulfite to hydrogen peroxide is 1:1.0 to 2.0.

[0012] In the above technical solution, the specific carrier gas is an inert gas such as nitrogen or argon, and the carrier gas flow rate is 0 ~ 500 mL / min.

[0013] In the above technical scheme, the catalyst is applicable to but not limited to titanium silicon molecular sieve catalysts such as TS-1 and TS-2.

[0014] The significant advantages of the present invention are:

[0015] The use of a fixed bed reactor for continuous catalytic oxidation to prepare vinyl sulfate can replace the traditional kettle reactor to achieve green, efficient and continuous synthesis of vinyl sulfate. The process uses a carrier gas to continuously pass into the reactor to remove the reaction products in time and reduce product hydrolysis; the continuous process has mild reaction conditions, simple product purification, and is easy to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a process flow chart of the present invention;

[0017] Figure 2 The schematic diagram of the main device flow of the present invention includes 1. nitrogen bottle, 2. raw material bottle, 3. pressure reducing valve, 4. needle valve, 5. rotor flowmeter, 6 one-way valve, 7. peristaltic pump, 8. jacketed static mixer, 9. temperature control device, 10. fixed bed reactor, 11 low temperature static liquid separation tank, 12. online detection system, and 13. liquid storage tank.

[0018] Figure 3 For fixed bed catalyst life evaluation. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0020] The analysis method and the calculation method of conversion rate and selectivity in the embodiment are as follows:

[0021] The qualitative and quantitative analysis of the product was carried out using a Shimadzu GC2010 gas chromatograph equipped with a SHIMADU brand SH-I-17 model capillary column (30m×0.25mm×0.25μm) and a FID detector. Dioxane was used as the internal standard and the internal standard method was used for quantitative detection.

[0022]

[0023] In order to better describe the present invention, the following examples are used as follows. Figure 2 The device shown includes a raw material bottle, a peristaltic pump, and a fixed bed reactor connected in sequence, a nitrogen bottle connected to the fixed bed reactor, and the fixed bed reactor is connected to a low-temperature static liquid separation tank and a liquid storage tank. A pressure reducing valve, a rotor flowmeter, and a one-way valve are also provided in sequence on the pipeline connecting the nitrogen bottle and the fixed bed reactor. A needle valve is provided on the pipeline connecting the fixed bed reactor and the condenser, and the gas-liquid mixture enters the low-temperature static liquid separation tank from the fixed bed reactor, the gas phase is discharged through the back pressure valve, the water phase is pumped to the wastewater collection section, and the organic phase enters the liquid storage tank for collection and sampling analysis.

[0024] Example 1 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower regions of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 35°C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60 mL / h, and the flow rate of hydrogen peroxide to 7.26 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 76% and 86% respectively by gas chromatography.

[0025] Example 2 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-2 is loaded on the reaction column of the fixed bed reactor, and the upper and lower regions of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 35°C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60 mL / h, and the flow rate of hydrogen peroxide to 7.26 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 69% and 66% respectively by gas chromatography.

[0026] Example 3 Prepare a 10% mass fraction of ethylene dichloride solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower areas of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 35°C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60 mL / h, and the flow rate of hydrogen peroxide to 7.26 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 74% and 71% respectively by gas chromatography.

[0027] Example 4 Prepare a 10% mass fraction of diethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower regions of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 55 ° C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60mL / h, and the flow rate of hydrogen peroxide to 7.26 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 66% and 82% respectively by gas chromatography.

[0028] Example 5 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower regions of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 55 ° C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60mL / h, and the flow rate of hydrogen peroxide to 7.26 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 94% and 94% respectively by gas chromatography.

[0029] Example 6 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower regions of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 55 ° C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60mL / h, and the flow rate of hydrogen peroxide to 8.47 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 97% and 86% respectively by gas chromatography.

[0030] Example 7 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower areas of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 55 ° C, the carrier gas flow rate to 0 mL / min, the flow rate of vinyl sulfite solution to 60 mL / h, and the flow rate of hydrogen peroxide to 7.26 mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite and the selectivity of vinyl sulfate are 86% and 91% respectively by gas chromatography.

[0031] Example 8 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Catalyst TS-1 is loaded on the reaction column of the fixed bed reactor, and the upper and lower areas of the catalyst layer in the reaction tube are filled with quartz sand. Purge with nitrogen. Set the temperature to 55 ° C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 120mL / h, and the flow rate of hydrogen peroxide to 14.52mL / h. After the reaction reaches stability, sampling and analysis are performed. The conversion rate of vinyl sulfite is 89% and the selectivity of vinyl sulfate is 93% by gas chromatography.

[0032] Example 9 Prepare a 10% mass fraction of dimethyl carbonate solution of vinyl sulfite and 30wt.% hydrogen peroxide for standby use. Load the catalyst TS-1 on the reaction column of the fixed bed reactor, and fill the upper and lower areas of the catalyst layer in the reaction tube with quartz sand. Purge with nitrogen gas. Set the temperature to 55 °C, the carrier gas flow rate to 100 mL / min, the flow rate of vinyl sulfite solution to 60 mL / h, and the flow rate of hydrogen peroxide to 8.47 mL / h. Sampling is performed at regular intervals and quantitative analysis is performed by gas chromatography to evaluate the catalyst cycle service life. The results are as follows: Figure 3 The titanium silicate molecular sieve TS-1 does not deactivate within 300 hours and has stable catalytic performance. Under the reaction conditions, the conversion rate of vinyl sulfite is maintained between 97-99%, while the selectivity of vinyl sulfate is maintained between 83-88%.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing vinyl sulfate by continuous oxidation of vinyl sulfite, characterized in that: The following steps are involved: (1) Preheating the raw material liquid and the oxidant liquid in a preset ratio; (2) The preheated liquid is transported to a fixed bed reactor filled with a catalyst. The reaction conditions are: temperature 5~100℃; raw material space velocity 0.1~30 h -1 ; Pressure 0.1~1.0 MPa; Carrier gas flow rate 0~500 mL / min; (3) After the reaction products are separated into layers, vinyl sulfate is obtained from the lower phase, and the lower phase is pumped to a storage tank for subsequent distillation and purification, and the upper aqueous phase is pumped to a wastewater collection section; The raw material liquid is an organic solution of vinyl sulfite, wherein the solvent used to dissolve the vinyl sulfite includes ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, dichloromethane or dichloroethane; The oxidant liquid is a hydrogen peroxide solution; the molar ratio of ethylene sulfite to hydrogen peroxide is 1:1.2; The carrier gas is nitrogen or argon; The catalyst is a titanium silicon molecular sieve catalyst; The method for obtaining vinyl sulfate from the lower phase is distillation purification.

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