WO2021003974A1 - 基于二氧化碳原料的碳酸丙烯酯制备方法 - Google Patents

基于二氧化碳原料的碳酸丙烯酯制备方法 Download PDF

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WO2021003974A1
WO2021003974A1 PCT/CN2019/122247 CN2019122247W WO2021003974A1 WO 2021003974 A1 WO2021003974 A1 WO 2021003974A1 CN 2019122247 W CN2019122247 W CN 2019122247W WO 2021003974 A1 WO2021003974 A1 WO 2021003974A1
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catalyst
carbon dioxide
propylene carbonate
reaction
ester
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PCT/CN2019/122247
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English (en)
French (fr)
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钟建交
李大海
曾智兵
罗荣昌
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惠州凯美特气体有限公司
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D317/00—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms
    • C07D317/08—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3
    • C07D317/10—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 not condensed with other rings
    • C07D317/32—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D317/34—Oxygen atoms
    • C07D317/36—Alkylene carbonates; Substituted alkylene carbonates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock

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  • the invention relates to the field of preparation methods of propylene carbonate, in particular to a preparation method of propylene carbonate based on carbon dioxide raw materials.
  • Carbon dioxide is considered to be a greenhouse gas and one of the main sources of global greenhouse effect. Therefore, reducing carbon dioxide emissions or Comprehensive utilization of carbon dioxide is of great significance for reducing the global greenhouse effect.
  • Converting carbon dioxide into organic carbonate is one of the effective ways to reduce carbon dioxide emissions.
  • the products include cyclic carbonate, acyclic carbonate and polycarbonate.
  • carbon dioxide and propylene oxide are used to synthesize propylene carbonate.
  • the produced propylene carbonate product is not only a solvent with excellent performance, but also an important organic chemical product. It has a wide range of applications in the fields of batteries, textiles, printing and dyeing, and polymer synthesis.
  • the traditional preparation process of propylene carbonate utilizes carbon dioxide and propylene oxide to react to produce propylene carbonate under the conditions of the cycloaddition reaction and the catalyst.
  • the traditional preparation process of propylene carbonate has at least the following disadvantages:
  • the catalyst is an important factor affecting the reaction speed and conversion rate of propylene oxide.
  • the general catalysts used in the preparation of propylene carbonate are potassium bromide, sodium bromide, and sodium iodide plasma liquids. However, the general catalysts The effect is not good, resulting in slower reaction speed of carbon dioxide and propylene oxide and lower conversion rate.
  • the reaction of carbon dioxide and propylene oxide to synthesize propylene carbonate is an exothermic reaction. Lowering the temperature and increasing the pressure is beneficial to the positive reaction. However, too low temperature is not conducive to the activation of carbon dioxide, propylene oxide and catalytic components, resulting in The reaction rate will slow down. Due to the poor catalytic effect of the liquid catalyst, in order to speed up the reaction rate, only a relatively high reaction temperature and pressure can be used. The generally used temperature is 250-300°C, and the pressure is generally controlled at 5-8MPa. However, higher temperatures and pressures increase the requirements for equipment and instruments, increase equipment investment, consume more energy, and increase the risk of production process control.
  • reaction temperature is too high, the reaction time is too long, and the pressure is too high, which will cause the reactants to easily decompose or generate by-products during the reaction process, resulting in a decrease in the production rate of propylene carbonate.
  • the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing propylene carbonate based on carbon dioxide raw materials with mild reaction conditions, good catalytic effect, high propylene oxide conversion rate, and high purity of the propylene carbonate finished product.
  • a method for preparing propylene carbonate based on carbon dioxide raw materials includes the following steps:
  • the ester-containing mixed liquid is passed into the distillation tower, and the distillation operation is performed to obtain the propylene carbonate finished product and the circulating catalytic concentrate, wherein the circulating catalytic concentrate includes the The catalyst and the promoter.
  • the mass ratio of the propylene oxide, the carbon dioxide, the catalyst, and the co-catalyst is 1:(1-3):(0.005-0.03):(0.005-0.03).
  • the catalyst is at least one of potassium bromide, sodium bromide, sodium iodide, and potassium iodide.
  • the promoter includes a melting promoting catalyst and a phase transfer catalyst, and the mass ratio of the melting promoting catalyst to the phase transfer catalyst is 1: (1 to 3).
  • the melting promotion catalyst is at least one of polyethylene glycol and polyethylene glycol fatty acid
  • the phase transfer catalyst is tetrabutylammonium bromide, benzyltriethylammonium chloride, At least one of trioctyl methyl ammonium chloride, tetrapropyl ammonium chloride, tetramethyl ammonium bromide, tetrabutyl ammonium iodide, triethylhexyl ammonium bromide and triethyl octyl ammonium bromide .
  • the gas-liquid separation operation includes a first gas-liquid separation operation and a second gas-liquid separation operation.
  • the temperature of the first gas-liquid separation operation is 60°C to 80°C.
  • the temperature of the second gas-liquid separation operation is 105°C to 150°C; the temperature of the distillation operation is 230°C to 240°C, and the pressure is 0.01 MPa to 0.05 MPa.
  • the mixed gas and the circulating catalytic concentrate, together with the propylene oxide, the carbon dioxide, the catalyst and the cocatalyst And pass into the reaction tower.
  • the ester-containing gas-liquid mixture before the operation of passing the ester-containing gas-liquid mixture into the separator, the ester-containing gas-liquid mixture is also passed into the heat exchanger for heat exchange operation to The circulating medium in the heat exchanger absorbs the heat in the ester-containing gas-liquid mixture.
  • the propylene carbonate product is also passed into the condenser for a condensation operation to reduce the temperature of the propylene carbonate product 25°C ⁇ 35°C.
  • the propylene oxide and the carbon dioxide before the propylene oxide, the carbon dioxide, the catalyst and the cocatalyst are introduced into the reaction tower, the propylene oxide and the carbon dioxide , the catalyst and the co-catalyst are passed into the preheater for preheating operation, so that the temperature of the propylene oxide, the carbon dioxide, the catalyst and the co-catalyst is increased to 130°C ⁇ 150°C.
  • the present invention has at least the following advantages:
  • This method can obtain propylene carbonate products with higher purity through the preparation, separation and purification of propylene carbonate; and the use of mild reaction temperature and pressure can prevent the reactants from decomposing or generating by-products during the reaction. Thereby increasing the production rate of propylene carbonate; and through the synergistic catalysis of the catalyst and the co-catalyst, it can accelerate the cleavage of the CO double bond of carbon dioxide, which has a better catalytic effect, makes the reaction more rapid and efficient, and improves the conversion rate of propylene oxide .
  • This method can achieve a better catalytic effect through a suitable mass ratio of propylene oxide, carbon dioxide, catalyst and cocatalyst.
  • the method adopts a phase transfer catalyst and a melting promoting catalyst, and the inorganic carbon dioxide can be transferred to the organic propylene oxide through the phase transfer catalyst, which can increase the ionic reaction activity of the catalyst and accelerate the reaction speed of carbon dioxide and propylene oxide;
  • the melting promoting catalyst can dissolve the catalyst and the above-mentioned phase transfer catalyst together, which can make the catalyst more miscible with carbon dioxide and propylene oxide, thereby promoting the catalytic effect of the catalyst.
  • Fig. 1 is a flow chart of steps of a method for preparing propylene carbonate based on carbon dioxide raw materials according to an embodiment of the present invention
  • FIG. 2 is a schematic structural diagram of a propylene carbonate preparation device using a carbon dioxide raw material-based propylene carbonate preparation method according to an embodiment of the present invention
  • FIG. 3 is a schematic structural diagram of a propylene carbonate preparation device using a carbon dioxide raw material-based propylene carbonate preparation method according to an embodiment of the present invention
  • FIG. 4 is a schematic structural diagram of a reaction tower of a propylene carbonate preparation device according to an embodiment of the present invention
  • FIG. 5 is a flow diagram of reaction materials in a reaction tower of a propylene carbonate preparation device according to an embodiment of the present invention
  • Fig. 6 is a schematic structural diagram of the first tray of the reaction tower of the propylene carbonate preparation device according to an embodiment of the present invention.
  • a method for preparing propylene carbonate based on carbon dioxide raw materials includes the following steps: S110, at a temperature of 130°C to 150°C and a pressure of 1.5MPa to 1.8MPa, Propylene oxide, carbon dioxide, catalyst and co-catalyst are introduced into the reaction tower, and after cycloaddition reaction occurs, a gas-liquid mixture containing ester is obtained. S120: Pass the ester-containing gas-liquid mixture into a separator to perform a gas-liquid separation operation to obtain a mixed gas and an ester-containing mixed liquid.
  • S130 Pass the ester-containing mixed liquid into a distillation tower to perform a distillation operation to obtain a finished product of propylene carbonate and a circulating catalytic concentrate.
  • the circulating catalytic concentrate includes the catalyst and the promoter.
  • step S110 is to prepare propylene carbonate by using propylene oxide, carbon dioxide, a catalyst and a co-catalyst, and the obtained ester-containing gas-liquid mixture includes carbon dioxide, propylene oxide, a catalyst and propylene carbonate.
  • Step S120 is to separate the ester-containing gas-liquid mixture into a mixed gas and an ester-containing mixed liquid.
  • the mixed gas includes carbon dioxide and propylene oxide
  • the ester-containing mixed liquid includes a catalyst, a co-catalyst, and propylene carbonate.
  • Step S130 is to purify the propylene carbonate product from the ester-containing mixed liquid. In this way, the preparation, separation and purification of propylene carbonate can be completed, and a finished product of propylene carbonate with higher purity can be obtained.
  • the catalyst and the co-catalyst have a synergistic catalytic effect.
  • the structure of carbon dioxide is stable, the double bond of CO is relatively strong, and a higher activation energy is required to break the double bond.
  • Propylene oxide is more active in nature and easier to open the ring. Under the action of a catalyst, the ring-opening reaction of propylene oxide is relatively Fast, but the CO double bond cleavage rate of carbon dioxide is slow, so the cycloaddition reaction rate is mainly determined by the CO double bond cleavage rate of carbon dioxide.
  • the co-catalyst can make the catalyst more miscible with carbon dioxide and propylene oxide, and can accelerate the cleavage rate of the C-O double bond of carbon dioxide, play a better catalytic effect, make the reaction more rapid and efficient, and improve the conversion rate of propylene oxide.
  • the reaction rate of carbon dioxide and propylene oxide is relatively high, so there is no need for higher reaction temperature and pressure, and mild reaction temperature and pressure can be used to reduce the impact on the equipment. , Instrument requirements, reduce equipment investment, reduce energy consumption, and reduce the risk of production process control. Moreover, the mild reaction temperature and pressure can prevent the reactants from decomposing or generating by-products during the reaction process, thereby increasing the production rate of propylene carbonate.
  • the mass ratio of the propylene oxide, the carbon dioxide, the catalyst, and the co-catalyst is 1:(1-3):(0.005-0.03):(0.005-0.03).
  • the mass ratio of propylene oxide, carbon dioxide, catalyst and co-catalyst is 1:2:0.01:0.012. It should be noted that the amount of catalyst and co-catalyst directly determines the reaction rate of propylene oxide and carbon dioxide, which in turn determines the yield of propylene carbonate. The yield of propylene carbonate increases as the quality of the catalyst and co-catalyst increases.
  • the increase in the yield of propylene carbonate is smaller than the increase in the catalyst and cocatalyst, and when the mass ratio of the catalyst, cocatalyst and propylene oxide is 1:0.005:0.005, the yield of propylene carbonate When the mass ratio of catalyst and co-catalyst to propylene oxide is 1:0.03:0.03, the yield of propylene carbonate is 99.8%; at this ratio, the amount of catalyst and co-catalyst, propylene carbonate There is almost no change in the yield. Therefore, when the mass ratio of propylene oxide, carbon dioxide, catalyst and cocatalyst is 1:(1 ⁇ 3):(0.005 ⁇ 0.03):(0.005 ⁇ 0.03), a better catalytic effect can be achieved.
  • the catalyst is at least one of potassium bromide, sodium bromide, sodium iodide and potassium iodide.
  • the catalyst is a common mixture of potassium bromide, sodium bromide, sodium iodide, and potassium iodide.
  • the catalyst is potassium bromide, sodium bromide, sodium iodide, or potassium iodide. It should be noted that these ionic liquids have a good catalytic effect on the carbene cycloaddition reaction.
  • the operation of passing propylene oxide, carbon dioxide, catalyst and co-catalyst into the reaction tower specifically includes: configuring the catalyst as a saturated solution, immersing the porous carrier in the saturated solution, and then drying Operate to obtain a catalytic fixed bed; pass propylene oxide, carbon dioxide, the catalytic fixed bed and the co-catalyst into the reaction tower.
  • the porous carrier is alumina porous particles, zinc oxide porous particles, chromium oxide porous particles, cadmium oxide porous particles, cobalt oxide porous particles, nickel oxide porous particles, molybdenum oxide porous particles or tin oxide porous particles.
  • the porous support is alumina porous particles.
  • the diameter of the porous carrier is 2 mm to 4 mm.
  • the diameter of the porous carrier is 3 mm.
  • the soaking time is 40-60 hours.
  • the soaking time is 48 hours.
  • the temperature of the drying operation is 140°C to 160°C, and the time is 5 to 7 hours.
  • the temperature of the drying operation is 150°C and the time is 6 hours.
  • the pores of the catalytic fixed bed can accommodate carbon dioxide and propylene oxide. As a catalytic fixed bed of carbon dioxide and propylene oxide, it can increase the contact time and contact area of the two, thereby speeding up the reaction. Increase the yield of propylene carbonate.
  • the promoter includes a melting promoting catalyst and a phase transfer catalyst, and the mass ratio of the melting promoting catalyst to the phase transfer catalyst is 1: (1 to 3).
  • the co-catalyst includes polyethylene glycol and tetrabutylammonium bromide, and the mass ratio of polyethylene glycol to tetrabutylammonium bromide is 5:7. It should be noted that the mass ratio of polyethylene glycol to tetrabutylammonium bromide is particularly important.
  • the mass ratio of polyethylene glycol is low, it may affect the mutual solubility of the catalyst and tetrabutylammonium bromide, thereby affecting To the synergistic promoting effect of tetrabutylammonium bromide on the catalyst. If the mass ratio of tetrabutylammonium bromide is low, it will directly affect the ionic reaction activity of the catalyst, and further affect the reaction speed of carbon dioxide and propylene oxide.
  • the melting promotion catalyst is at least one of polyethylene glycol and polyethylene glycol fatty acid
  • the phase transfer catalyst is tetrabutylammonium bromide, benzyltriethylammonium chloride, trioctyl At least one of methylammonium chloride, tetrapropylammonium chloride, tetramethylammonium bromide, tetrabutylammonium iodide, triethylhexylammonium bromide, and triethyloctylammonium bromide.
  • the melting promoting catalyst is a common mixture of polyethylene glycol and polyethylene glycol fatty acid.
  • the melting promoting catalyst is polyethylene glycol or polyethylene glycol fatty acid.
  • the phase transfer catalyst is tetrabutyl ammonium bromide, benzyl triethyl ammonium chloride, trioctyl methyl ammonium chloride, tetrapropyl ammonium chloride, tetramethyl ammonium bromide, tetrabutyl iodide A common mixture of ammonium chloride, triethylhexylammonium bromide and triethyloctylammonium bromide.
  • the phase transfer catalyst is tetrabutyl ammonium bromide, benzyl triethyl ammonium chloride, trioctyl methyl ammonium chloride, tetrapropyl ammonium chloride, tetramethyl ammonium bromide, tetrabutyl iodide Ammonium chloride, triethylhexylammonium bromide or triethyloctylammonium bromide.
  • the above-mentioned phase transfer catalyst can transfer inorganic carbon dioxide to organic propylene oxide, can increase the ionic reaction activity of the catalyst, and accelerate the reaction rate of carbon dioxide and propylene oxide.
  • the aforementioned melting promoting catalyst is an excellent chemical melting promoter, which can dissolve the catalyst and the aforementioned phase transfer catalyst together, and can make the catalyst more miscible with carbon dioxide and propylene oxide, thereby promoting the catalytic effect of the catalyst.
  • the gas-liquid separation operation includes a first gas-liquid separation operation and a second gas-liquid separation operation.
  • the temperature of the first gas-liquid separation operation is 60°C to 80°C.
  • the temperature of the gas-liquid separation operation is 105°C to 150°C.
  • the temperature of the distillation operation is 230°C to 240°C, and the pressure is 0.01 MPa to 0.05 MPa.
  • the atmospheric boiling point of propylene carbonate is 240°C
  • the boiling points of the catalyst and the melting catalyst are higher than that of propylene carbonate
  • the boiling point of the phase transfer catalyst is about 100°C.
  • the mixed gas obtained by the gas-liquid separation operation contains a phase transfer catalyst in addition to propylene oxide and carbon dioxide.
  • the mixed gas and the circulating catalytic concentrate, together with the propylene oxide, the carbon dioxide, the catalyst, and the co-catalyst are also passed through Into the reaction tower.
  • the mixed gas is recycled into the reaction tower, thereby reducing carbon dioxide costs and reducing greenhouse gas emissions.
  • the circulating catalytic concentrate is recycled into the reaction tower, thereby reducing the cost of the catalyst.
  • the ester-containing gas-liquid mixture before the operation of passing the ester-containing gas-liquid mixture into the separator, the ester-containing gas-liquid mixture is also passed into the heat exchanger for heat exchange operation, so that the The circulating medium in the heat exchanger absorbs the heat in the ester-containing gas-liquid mixture.
  • the circulating medium in the heat exchanger is propylene oxide that has not been passed into the reaction tower. The heat exchanger exchanges heat between the propylene oxide and the ester-containing gas-liquid mixture. In this way, the heat of reaction is recovered and utilized.
  • the propylene carbonate product is also passed into the condenser for a condensation operation, so that the temperature of the propylene carbonate product is reduced to 25°C ⁇ 35°C. It should be noted that the propylene carbonate product is condensed by the condenser, and the temperature of the propylene carbonate product is reduced to room temperature, so that the propylene carbonate product is converted from the gas phase to the liquid phase.
  • the propylene oxide, the carbon dioxide, the catalyst and the cocatalyst are passed into a preheater to perform a preheating operation to increase the temperature of the propylene oxide, the carbon dioxide, the catalyst and the co-catalyst to 130°C to 150°C.
  • the propylene oxide, carbon dioxide, catalyst and co-catalyst can reach the cycloaddition reaction temperature before entering the reaction tower, so that the reaction conditions of the cycloaddition reaction are more stable and the reaction is more stable.
  • the present invention has at least the following advantages:
  • This method can obtain propylene carbonate products with higher purity through the preparation, separation and purification of propylene carbonate; and the use of mild reaction temperature and pressure can prevent the reactants from decomposing or generating by-products during the reaction. Thereby increasing the production rate of propylene carbonate; and through the synergistic catalysis of the catalyst and the co-catalyst, it can accelerate the cleavage of the CO double bond of carbon dioxide, which has a better catalytic effect, makes the reaction more rapid and efficient, and improves the conversion rate of propylene oxide .
  • This method can achieve a better catalytic effect through a suitable mass ratio of propylene oxide, carbon dioxide, catalyst and cocatalyst.
  • the method adopts a phase transfer catalyst and a melting promoting catalyst, and the inorganic carbon dioxide can be transferred to the organic propylene oxide through the phase transfer catalyst, which can increase the ionic reaction activity of the catalyst and accelerate the reaction speed of carbon dioxide and propylene oxide;
  • the melting promoting catalyst can dissolve the catalyst and the above-mentioned phase transfer catalyst together, which can make the catalyst more miscible with carbon dioxide and propylene oxide, thereby promoting the catalytic effect of the catalyst.
  • a propylene carbonate preparation device 10 using a carbon dioxide raw material-based propylene carbonate preparation method includes an inlet and outlet assembly 110, a reaction assembly 120, a separation assembly 130, and a distillation assembly 140.
  • the inlet and outlet assembly 110 includes a carbon dioxide inlet pipe 111, a catalyst inlet pipe 112, a propylene oxide inlet pipe 113, and a heat exchanger 114.
  • the heat exchanger 114 is provided with a first heat exchange cavity and a second heat exchange cavity which are isolated from each other. In the heat exchange cavity, the propylene oxide inflow pipe 113 is in communication with the first heat exchange cavity.
  • the reaction assembly 120 includes a reaction tower 121 and a reaction mixture outflow pipe 122.
  • the reaction tower 121 includes an upper head, a tower body, and a lower head. The upper head and the lower head are respectively connected to the tower body.
  • the lower head is connected to the carbon dioxide inlet pipe 111, the catalyst inlet pipe 112 and the first heat exchange cavity respectively, and the first end of the reaction mixture outflow pipe 122 is connected to the upper head Connected, the second end of the reaction mixture outflow pipe 122 is in communication with the second heat exchange cavity.
  • the separation assembly 130 includes a separator group 131, a carbon dioxide outflow pipe 132, and a crude propylene carbonate outflow pipe 133.
  • the separator group 131 is in communication with the second heat exchange cavity, and the top of the separator group 131 is connected to the The carbon dioxide outflow pipe 132 is in communication, and the bottom of the separator group 131 is in communication with the first end of the crude propylene carbonate outflow pipe 133.
  • the distillation assembly 140 includes a distillation tower 141, a propylene carbonate product outflow pipe 142, and a catalyst outflow pipe 143.
  • the distillation tower 141 is in communication with the second end of the propylene carbonate crude product outflow pipe 133.
  • the top part is in communication with the first end of the propylene carbonate product outflow pipe 142, and the bottom part of the distillation tower 141 is in communication with the catalyst outflow pipe 143.
  • the condensing assembly 150 includes a condenser 151 and a propylene carbonate product flow pipe 152.
  • the first end of the condenser 151 communicates with the second end of the propylene carbonate product outflow pipe 142, and the first end of the condenser 151 The two ends are communicated with the first end of the propylene carbonate product circulation pipe 152.
  • the propylene carbonate product storage tank 160 is in communication with the second end of the propylene carbonate product circulation pipe 152.
  • the above-mentioned carbon dioxide raw material-based propylene carbonate preparation device 10 is described: taking the catalyst as potassium iodide, the co-catalyst is polyethylene glycol and tetrabutylammonium bromide as an example, the propylene oxide inflow pipe 113 passes the propylene oxide to be reacted Into the first heat exchange cavity of the heat exchanger 114, the second heat exchange cavity is used to contain the ester-containing gas-liquid mixture, the propylene oxide in the first heat exchange cavity and the ester-containing gas-liquid in the second heat exchange cavity The mixture exchanges heat.
  • the propylene oxide absorbs the heat of the ester-containing gas-liquid mixture
  • the propylene oxide is passed into the reaction tower 121, and the carbon dioxide and the catalyst are respectively introduced through the carbon dioxide inlet pipe 111 and the catalyst inlet pipe 112, and the reaction tower 121 is heated and added.
  • the pressure is brought to a temperature of 130°C to 150°C and a pressure of 1.5MPa to 1.8MPa.
  • the carbon dioxide is in the gas phase
  • the propylene oxide, the catalyst and the co-catalyst are in the liquid phase.
  • Carbon dioxide and propylene oxide synthesize propylene carbonate under the synergistic catalysis of a catalyst and a co-catalyst to obtain an ester-containing gas-liquid mixture.
  • the reaction mixture outflow pipe 122 passes the ester-containing gas-liquid mixture into the separator group 131, and the temperature of the separator is reduced to 105°C to 150°C to perform the gas-liquid separation operation on the ester-containing gas-liquid mixture.
  • propylene oxide and tetrabutylammonium bromide are converted from a liquid phase to a gas phase, together with carbon dioxide, as a mixed gas, are output from the carbon dioxide outflow pipe 132.
  • the propylene carbonate, the catalyst and the polyethylene glycol are still in the liquid phase, together as an ester-containing mixed liquid, and pass into the distillation tower 141 from the crude propylene carbonate outflow pipe 133.
  • the distillation column 141 is heated and pressurized so that the temperature reaches 230° C. to 240° C. and the pressure reaches 0.01 MPa to 0.05 MPa, and the ester-containing mixed liquid is subjected to distillation operation.
  • the catalyst and polyethylene glycol are still in the liquid phase, together as the circulating catalytic concentrate, and stay in the distillation tower 141.
  • the normal pressure boiling point of propylene carbonate is 240° C., and it is converted into a gas phase under this high temperature and high pressure condition, as a finished product of propylene carbonate, which flows into the condenser 151 from the outflow pipe 142 of the finished propylene carbonate.
  • the condenser 151 performs a condensing operation on the propylene carbonate product to reduce the temperature of the propylene carbonate product to normal temperature, so that the propylene carbonate product is converted from a gas phase to a liquid phase.
  • the propylene carbonate product circulation pipe 152 passes the condensed propylene carbonate product into the propylene carbonate product storage tank 160 for storage. In this way, a finished product of propylene carbonate with a purity of propylene carbonate above 99% can be obtained.
  • the heat exchange between propylene oxide and the ester-containing gas-liquid mixture is carried out through the heat exchanger 114.
  • the initial amount of propylene oxide before entering the reaction tower 121 is increased.
  • Temperature and lower the initial temperature before the separation of the ester-containing gas-liquid mixture thereby shortening the heating time of propylene oxide and the cooling time of the ester-containing gas-liquid mixture, thereby reducing energy consumption.
  • the feed-in/outlet assembly 110 further includes a carbon dioxide heater 115, and the carbon dioxide heater 115 is arranged on the carbon dioxide inlet pipe 111. It should be noted that the carbon dioxide heater 115 raises the temperature of carbon dioxide to 130°C to 150°C.
  • the inlet and outlet assembly 110 further includes a propylene oxide pressurizing pump 116, and the propylene oxide pressurizing pump 116 and the propylene oxide inflow pipe 113 are far away from the One end of the first heat exchange cavity is connected.
  • the propylene oxide pressure pump 116 can increase the pressure of the propylene oxide fluid to prevent it from being unable to enter the reaction tower 121 due to insufficient pressure. It can also control the flow rate of propylene oxide, thereby controlling the propylene oxide flow rate during the reaction. Dosage.
  • the inlet and outlet assembly 110 also includes a propylene oxide transition connecting pipe 117.
  • the propylene oxide transition connecting pipe 117 is connected to the lower head and the first The heat exchange cavity is connected.
  • the inlet and outlet assembly 110 further includes a propylene oxide heater 118, and the propylene oxide heater 118 is arranged on the propylene oxide transition connecting pipe 117. It should be noted that the temperature of the propylene oxide after heat exchange is increased to 130°C to 150°C by the propylene oxide heater 118.
  • the separator group 131 includes a primary separator 1311, a secondary separator 1312, and a tetrabutylammonium bromide outflow pipe 1313.
  • the primary separator 1311 is in communication with the second heat exchange cavity
  • the secondary separator 1312 is in communication with the primary separator 1311
  • the top of the primary separator 1311 is connected to the carbon dioxide outflow pipe 132 is connected
  • the first end of the tetrabutylammonium bromide outflow pipe 1313 is in communication with the top of the secondary separator 1312
  • the second end of the tetrabutylammonium bromide outflow pipe 1313 is connected with the carbon dioxide outflow
  • the pipe 132 is in communication
  • the bottom of the group 131 of the secondary separator 1312 is in communication with the first end of the crude propylene carbonate outflow pipe 133.
  • the temperature of the first-stage separator 1311 is controlled at 60°C to 80°C, and the carbon dioxide is discharged through the carbon dioxide outflow pipe 132. Carbon dioxide and propylene oxide in ester gas-liquid mixtures. Then control the temperature of the secondary separator 1312 at 105°C ⁇ 150°C, and drain the tetrabutylammonium bromide through the tetrabutylammonium bromide outflow pipe 1313, so that only potassium iodide and polyethylene are left in the ester-containing gas-liquid mixture. Alcohol and propylene carbonate. In this way, the effective distillation operation can be ensured, thereby ensuring the purity of the finished propylene carbonate.
  • the distillation assembly 140 further includes a steam generator 144, and the steam generator 144 is in communication with the distillation tower 141. It should be noted that the steam generator 144 provides high-temperature steam for the distillation tower 141 to increase the temperature of the distillation tower 141 to 230°C to 240°C.
  • the separation assembly 130 further includes a carbon dioxide return pipe 134, a first end of the carbon dioxide return pipe 134 is in communication with the carbon dioxide outflow pipe 132, and the carbon dioxide return pipe 134 The second end of is communicated with the carbon dioxide inlet pipe 111. It should be noted that the carbon dioxide return pipe 134 can recover carbon dioxide and propylene oxide into the reaction tower 121, thereby reducing the cost of carbon dioxide and reducing greenhouse gas emissions.
  • the distillation assembly 140 further includes a catalyst return pipe 145, a first end of the catalyst return pipe 145 is in communication with the catalyst outflow pipe 143, and the catalyst return pipe 145 The second end of is communicated with the catalyst inlet pipe 112. It should be noted that the catalyst return pipe 145 can recover the catalyst and part of the co-catalyst into the reaction tower 121, thereby reducing the cost of the catalyst.
  • the condensing assembly 150 further includes a propylene carbonate product return pipe 153.
  • the second end of the propylene carbonate product reflux pipe 153 is in communication with the distillation tower 141. It should be noted that the temperature in the distillation tower 141 is 230°C to 240°C, and the reaction temperature required for the reaction tower 121 is 130°C to 150°C. Therefore, the catalyst and some co-catalysts need to be recycled before being recycled into the reaction tower 121.
  • the present invention refluxes part of the condensed propylene carbonate product to the distillation tower 141 through the propylene carbonate product return pipe 153.
  • the catalyst and part of the co-catalyst in the tower 141 exchange heat to reduce the temperature of the catalyst and part of the co-catalyst to 130°C to 150°C, and then be recycled into the reaction tower 121. In this way, the catalyst and part of the co-catalyst before the recovery can be recovered. While the catalyst performs the function of condensation, it can also reduce equipment costs and equipment footprint. [0068] Please also refer to Figure 4, Figure 5 and Figure 6, the following is the reaction tower part of the propylene carbonate preparation device.
  • a reaction tower 10 of a propylene carbonate preparation device includes a tower body 110, a tray assembly 120 and a net ring packing assembly 130.
  • the tower body 110 includes an upper head 111, a tower body 112, and a lower head 113.
  • the upper head 111 and the lower head 113 are respectively connected to two ends of the tower body 112, and the lower head 113 is provided with a carbon dioxide feed port 1131, a propylene oxide feed port 1132, and a catalyst feed port 1133.
  • the tower body 112 is provided with a reaction chamber 1121, and the upper head 111 is provided with a propylene carbonate feed port 1111.
  • the tray assembly 120 is disposed in the reaction chamber 1121, the tray assembly 120 includes multiple sets of offset trays 121, and each set of offset trays 121 includes a first tray 1211 and a second tray 1212, the first tray 1211 is fixed to the inner wall of the tower body 112, the first tray 1211 includes a first physical area 1211a and a first circulation area 1211b, the second tray 1212 is connected to the tower The inner wall of the body 112 is fixed, the second tray 1212 includes a second physical area 1212a and a second circulation area 1212b, the first physical area 1211a is arranged facing the second circulation area 1212b, the second physical area 1212a Facing the first circulation zone 1211b, the first circulation zone 1211b is provided with a plurality of first circulation holes 1211b1, and each of the first circulation holes 1211b1 is connected to the first tray 1211 and the second tray respectively.
  • the reaction compartment enclosed between the plates 1212 communicates with each other.
  • the second circulation area 1212b is provided with a plurality of second circulation holes, and each of the second circulation holes is connected to the first tray 1211 and the first The reaction compartment enclosed by the two trays 1212 is connected.
  • the mesh ring filling assembly 130 includes a plurality of mesh ring groups 131, the plurality of mesh ring groups 131 are all filled in the reaction chamber 1121, and each of the mesh ring groups 131 is correspondingly filled in one of the reaction compartments .
  • the carbon dioxide, propylene oxide, catalyst and co-catalyst are respectively introduced into the reaction chamber from the bottom of the tower body through the carbon dioxide feed port, propylene oxide feed port and catalyst feed port.
  • carbon dioxide, propylene oxide, catalyst and co-catalyst are used as reaction materials.
  • Carbon dioxide and propylene oxide undergo a cycloaddition reaction under the catalysis of a catalyst to be converted into propylene carbonate.
  • the cycloaddition reaction is high temperature and high pressure, and the temperature and pressure of the reaction chamber reach the reaction conditions by heating and pressurizing the reaction tower.
  • the reaction conditions are temperature conditions of 130° C. to 150° C.
  • reaction materials will baffle and rise alternately along the first and second circulation holes of the tray. Compared with the direct current rise, the flow rate of the reaction materials will be reduced, thereby increasing the contact time and contact area between the reaction materials, and thus The reaction between the reaction materials is more complete and the conversion rate is higher.
  • the propylene oxide, catalyst and co-catalyst are in liquid phase, with high density, and the rising speed is relatively slow. Generally, they accumulate on the surface of the tray, while carbon dioxide is in the gas phase with low density and a relatively slow rising speed. Fast, generally gather in the middle and upper part between the first tray and the second tray, that is, the middle and upper part of the reaction compartment. When the carbon dioxide gas hits the net ring group during the ascent process, the net ring changes the forward direction. The lower dispersion rushes between the propylene oxide, the catalyst and the co-catalyst, so that the reaction materials are fully mixed and the reaction yield is improved.
  • the inner diameter of the reaction tower body is 50 mm to 70 mm, and the length of the reaction tower body is 800 mm to 1200 mm.
  • a feed mixing cavity 1134 is provided between the lower head 113 and the reaction chamber 1121, and an outlet is provided between the upper head 111 and the reaction chamber 1121 ⁇ Mixing cavity 1112. It should be noted that under high temperature and high pressure reaction conditions, the feed mixing chamber and the discharge mixing chamber can temporarily store reaction materials and reaction products, avoiding excessive pressure of reaction materials into the reaction chamber due to the pressure of the reaction tower And too much reaction products are forced out of the reaction chamber, resulting in the phenomenon of jet leakage.
  • the network ring group 131 includes multiple network rings 1311.
  • the mesh ring includes a first mesh ring body and a second mesh ring body.
  • the second mesh ring body is disposed in the first mesh ring body and connected to the first mesh ring body.
  • the body is provided with a plurality of first meshes
  • the second mesh ring body is provided with a plurality of second meshes
  • the first mesh is located between two adjacent second meshes
  • the second The mesh is located between two adjacent first meshes.
  • the dislocation mesh of the first mesh ring body and the second mesh ring body increases the flow path of the reaction materials, can reduce the flow rate of the reaction materials, thereby increasing the contact time and contact area between the reaction materials. In turn, the reaction between the reaction materials is more complete and the conversion rate is higher.
  • the diameter of the mesh ring is 2mm-4mm. In this way, the diameter of the appropriate mesh ring will make the flow rate of the reaction material more appropriate.
  • first tray is a circular plate structure, and the area of the first physical area and the first circulation area are equal.
  • second tray is a circular plate structure, and the area of the second physical area and the second circulation area are equal.
  • the boundary between the first physical area and the first circulation area is a straight line. In this way, the area distribution between the physical area and the circulation area is more reasonable.
  • first circulation holes and the second circulation holes are arranged at even intervals.
  • the diameter of the first circulation hole is 0.5mm-2mm; the diameter of the second circulation hole is 0.5mm-2mm.
  • the diameter of the first circulation hole is 0.5 mm, 1 mm, 1.5 mm, or 2 mm; the diameter of the second circulation hole is 0.5 mm, 1 mm, 1.5 mm, or 2 mm. It should be noted that if the diameter of the circulation hole is too large, the flow of the reaction material passing through the circulation hole will be too large, which is not conducive to the full contact between the reaction materials; if the diameter of the circulation hole is too small, the reaction material cannot pass through. Numerous experiments and practices have proved that the diameter of the circulation hole is preferably 0.5mm to 2mm.
  • the ratio of the total area of the first circulation holes of each of the first trays to the total area of the carbon dioxide feed port, the propylene oxide feed port and the catalyst feed port is 20: 1.
  • the ratio of the total area of the first circulation holes of each of the second trays to the total area of the carbon dioxide feed port, the propylene oxide feed port and the catalyst feed port is 20:1. It should be noted that this can ensure a sufficiently large area of the circulation hole to reduce the flow rate of the reaction materials, thereby increasing the contact area and contact time between the reaction materials, and thereby fully contacting the reaction materials.
  • the ester-containing mixed liquid is passed into the distillation tower, and the distillation operation is performed to obtain the propylene carbonate product and the circulating catalytic concentrate of Example 1 .
  • the circulating catalytic concentrate includes the catalyst and the promoter.
  • the ester-containing mixed liquid is passed into the distillation tower, and the distillation operation is performed to obtain the propylene carbonate finished product and the circulating catalytic concentrate of Example 2 .
  • the circulating catalytic concentrate includes the catalyst and the promoter.
  • the ester-containing mixed liquid is passed into the distillation tower, and the distillation operation is performed to obtain the propylene carbonate finished product and the circulating catalytic concentrate of Example 3 .
  • the circulating catalytic concentrate includes the catalyst and the promoter.
  • the ester-containing mixed liquid is passed into the distillation tower, and the distillation operation is performed to obtain the propylene carbonate product and the circulating catalytic concentrate of Example 4 .
  • the circulating catalytic concentrate includes the catalyst and the promoter.
  • the ester-containing gas-liquid mixture is passed into the separator, and the gas-liquid separation operation is performed to obtain a mixed gas and an ester-containing mixed liquid.
  • the ester-containing mixed liquid was passed into the distillation tower for distillation operation to obtain the finished product of propylene carbonate and the circulating catalytic concentrate of Comparative Example 2.
  • the circulating catalytic concentrate includes the catalyst and the promoter.
  • Example 1 For the finished propylene carbonate products of Example 1, Example 2, Example 3, Example 4, Comparative Example 1, and Comparative Example 2, the composition was determined by gas chromatography and calculated
  • Example 3 Comparative Example 1, and Comparative Example 2, the conversion of propylene oxide and the purity of the propylene carbonate product were performed. The results are shown in Table 1.
  • Example 2 99.8 100.0
  • Example 3 99.2 100.0
  • Example 4 98.3 100.0 Comparative example 1 76.5 82.8 Comparative example 2 68.6 71.2
  • Comparative 1 did not use a co-catalyst, resulting in a low conversion rate of propylene oxide; Comparative 1 did not perform the analysis on the ester-containing gas-liquid mixture. Separation and purification results in low purity of the propylene carbonate product.
  • Comparative Example 2 increased the temperature and pressure of the cycloaddition reaction, the amount of catalyst used was too low, and the amount of co-catalyst used was too high, resulting in a low conversion rate of propylene oxide; The mixture is separated and purified. However, at a temperature of 80°C, tetrabutylammonium bromide is a liquid phase and remains in the ester-containing mixture; at a temperature of 150°C and a pressure of 0.03MPa, carbonic acid Propylene ester cannot be separated from polyethylene glycol, resulting in low purity of the propylene carbonate product.

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Abstract

本发明涉及碳酸丙烯酯制备方法领域，公开了一种基于二氧化碳原料的碳酸丙烯酯制备方法，包括以下步骤：在130℃～150℃的温度条件下，以及1.5MPa～1.8MPa的压力条件下，将环氧丙烷、二氧化碳、催化剂及助催化剂通入至反应塔内，发生环加成反应后，得到含酯气液混合物；将含酯气液混合物通入至分离器内，进行气液分离操作，得到混合气体及含酯混合液；将含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到碳酸丙烯酯成品及循环催化浓缩液，其中，循环催化浓缩液包括催化剂及助催化剂。本方法通过催化剂与助催化剂的协同催化，能够加快二氧化碳的C-O双键断裂速度，更好的起到了催化效果，使反应更加迅速高效，从而提高环氧丙烷转化率。

Description

基于二氧化碳原料的碳酸丙烯酯制备方法 技术领域
本发明涉及碳酸丙烯酯制备方法领域，特别是涉及一种基于二氧化碳原料的碳酸丙烯酯制备方法。
背景技术
自工业革命以来，化石燃料被大量使用，在其燃烧加工过程中排放过多的二氧化碳，二氧化碳被认为是一种温室气体，是造成全球温室效应的主要来源之一，因此减少二氧化碳的排放或对二氧化碳加以综合利用对减轻全球温室效应具有重要意义。
将二氧化碳转化为有机碳酸酯是减少二氧化碳排放的有效途径之一，目前产物有环状碳酸酯，非环状碳酸酯和聚碳酸酯三大类，其中二氧化碳和环氧丙烷合成碳酸丙烯酯是用途广泛的领域，生成的碳酸丙烯酯产品不仅是一种性能优良的溶剂，而且是一种重要的有机化工产品，在电池、纺织、印染、高分子合成领域都有广泛的应用。
传统的碳酸丙烯酯制备工艺是利用二氧化碳和环氧丙烷在环加成反应条件以及催化剂的催化下，反应生成碳酸丙烯酯。传统的碳酸丙烯酯制备工艺至少具有以下缺点：
1、催化剂是影响环氧丙烷的反应速度及转化率的重要因素，应用在碳酸丙烯酯制备方法的一般催化剂为溴化钾、溴化钠、碘化钠体等离子液，然而，一般催化剂的催化效果不佳，导致二氧化碳和环氧丙烷的反应速度较慢以及转化率较低。
2、二氧化碳和环氧丙烷合成碳酸丙烯酯的反应，属于放热反应，降低温度和提高压力有利于向正反应方向进行，然而温度太低不利于二氧化碳、环氧丙烷和催化成分的活化，导致反应速率会变慢。由于液体催化剂的催化效果不佳，为了加快反应速率，只能采用偏高的反应温度及压力，一般采用的温度为250～300℃，压力一般控制在5～8MPa。然而，温度、压力偏高对设备、仪表的要求提高，设备投资增大，耗能较大，生产过程控制的危险性也增强。而且，反应温度过高、反应时间过长以及压力过高，会导致反应物在反应过程中容易分解或生成副产物，导致碳酸丙烯酯的生成率降低。
3、环加成反应后，碳酸丙烯酯与催化剂互溶，难以分离，导致制备的碳酸丙烯酯成品纯度较低。
发明内容
本发明的目的是克服现有技术中的不足之处，提供一种反应条件温和、催化效果好、环氧丙烷转化率高、碳酸丙烯酯成品纯度高的基于二氧化碳原料的碳酸丙烯酯制备方法。
本发明的目的是通过以下技术方案来实现的：
一种基于二氧化碳原料的碳酸丙烯酯制备方法，包括以下步骤：
在130℃～150℃的温度条件下，以及1.5MPa～1.8MPa的压力条件下，将环氧丙烷、二氧化碳、催化剂及助催化剂通入至反应塔内，发生环加成反应后，得到含酯气液混合物；
将所述含酯气液混合物通入至分离器内，进行气液分离操作，得到混合气体及含酯混合液；
以及0.01MPa～0.05MPa的压力条件下，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到碳酸丙烯酯成品及循环催化浓缩液，其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
在其中一种实施方式，所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂的质量比例为1:(1～3):(0.005～0.03):(0.005～0.03)。
在其中一种实施方式，所述催化剂为溴化钾、溴化钠、碘化钠和碘化钾中至少一种。
在其中一种实施方式，所述助催化剂包括促融催化剂及相转移催化剂，所述促融催化剂与所述相转移催化剂的质量比例为1:(1～3)。
在其中一种实施方式，所述促融催化剂为聚乙二醇和聚乙二醇脂肪酸中至少一种，所述相转移催化剂为四丁基溴化铵、苯甲基三乙基氯化铵、三辛基甲基氯化铵、四丙基氯化铵、四甲基溴化铵、四丁基碘化铵、三乙基己基溴化铵和三乙基辛基溴化铵中至少一种。
在其中一种实施方式，所述气液分离操作包括第一次气液分离操作及第二次气液分离操作，所述第一次气液分离操作的温度为60℃～80℃，所述第二次气液分离操作的温度为105℃～150℃；所述蒸馏操作的温度为230℃～240℃，压力为0.01MPa～0.05MPa。
在其中一种实施方式，在所述环加成反应时，还将所述混合气体及所述循环催化浓缩液，连同所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂一并通入至所述反应塔内。
在其中一种实施方式，在将所述含酯气液混合物通入至所述分离器的操作之前，还将所述含酯气液混合物通入至换热器内，进行换热操作，以使所述换热器内的流通介质吸收所述含酯气液混合物内的热量。
在其中一种实施方式，在得到所述碳酸丙烯酯成品的操作之后，还将所述碳酸丙烯酯成品通入至冷凝器内，进行冷凝操作，以使所述碳酸丙烯酯成品的温度降至25℃～35℃。
在其中一种实施方式，在将所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂通入至所述反应塔内的操作之前，还将所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂通入至预热器内，进行预热操作，以使所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂的温度升高至130℃～150℃。
与现有技术相比，本发明至少具有以下优点：
1、本方法通过对碳酸丙烯酯的制备、分离及提纯，能够得到纯度较高的碳酸丙烯酯成品；且采用温和的反应温度及压力，能够避免反应物在反应过程中分解或生成副产物，从而提高碳酸丙烯酯的生成率；且通过催化剂与助催化剂的协同催化，能够加快二氧化碳的C-O双键断裂速度，更好的起到了催化效果，使反应更加迅速高效，从而提高环氧丙烷转化率。
2、本方法通过合适的环氧丙烷、二氧化碳、催化剂及助催化剂的质量比例，可以达到较佳的催化效果。
3、本方法采用相转移催化剂和促融催化剂，通过相转移催化剂能将无机的二氧化碳转移到有机的环氧丙烷上，能够增大催化剂的离子反应活性，加快二氧化碳与环氧丙烷的反应速度；通过促融催化剂能够使得催化剂以及上述相转移催化剂溶解在一起，能够使得催化剂与二氧化碳及环氧丙烷更加互溶，从而促进催化剂的催化效果。
附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，应当理解，以下附图仅示出了本发明的某些实施例，因此不应被看作是对范围的限定，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本发明一实施方式的基于二氧化碳原料的碳酸丙烯酯制备方法的步骤流程图；
图2为本发明一实施方式的应用基于二氧化碳原料的碳酸丙烯酯制备方法的碳酸丙烯酯制备装置的结构示意图；
图3为本发明一实施方式的应用基于二氧化碳原料的碳酸丙烯酯制备方法的碳酸丙烯酯制备装置的结构示意图；
图4为本发明一实施方式的碳酸丙烯酯制备装置的反应塔的结构示意图；
图5为本发明一实施方式的碳酸丙烯酯制备装置的反应塔的反应物料流通图；
图6为本发明一实施方式的碳酸丙烯酯制备装置的反应塔的第一塔板的结构示意图。
具体实施方式
为了便于理解本发明，下面将参照相关附图对本发明进行更全面的描述。附图中给出了本发明的较佳实施方式。但是，本发明可以以许多不同的形式来实现，并不限于本文所描述的实施方式。相反地，提供这些实施方式的目的是使对本发明的公开内容理解的更加透彻全面。
需要说明的是，当元件被称为“固定于”另一个元件，它可以直接在另一个元件上或者也可以存在居中的元件。当一个元件被认为是“连接”另一 个元件，它可以是直接连接到另一个元件或者可能同时存在居中元件。本文所使用的术语“垂直的”、“水平的”、“左”、“右”以及类似的表述只是为了说明的目的，并不表示是唯一的实施方式。
除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文中在本发明的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是旨在于限制本发明。本文所使用的术语“及/或”包括一个或多个相关的所列项目的任意的和所有的组合。
一实施方式，请参阅图1，一种基于二氧化碳原料的碳酸丙烯酯制备方法，包括以下步骤：S110，在130℃～150℃的温度条件下，以及1.5MPa～1.8MPa的压力条件下，将环氧丙烷、二氧化碳、催化剂及助催化剂通入至反应塔内，发生环加成反应后，得到含酯气液混合物。S120，将所述含酯气液混合物通入至分离器内，进行气液分离操作，得到混合气体及含酯混合液。S130，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到碳酸丙烯酯成品及循环催化浓缩液。其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
对上述基于二氧化碳原料的碳酸丙烯酯制备方法进行说明：
第一，步骤S110是通过环氧丙烷、二氧化碳、催化剂及助催化剂来制备碳酸丙烯酯，得到的含酯气液混合物包括二氧化碳、环氧丙烷、催化剂及碳酸丙烯酯。步骤S120是将含酯气液混合物分离为混合气体及含酯混合液，混合气体包括二氧化碳及环氧丙烷，含酯混合液包括催化剂、助催化剂及碳酸丙烯酯。步骤S130是从含酯混合液中提纯出碳酸丙烯酯成品。如此可以完成碳酸丙烯酯的制备、分离及提纯，得到纯度较高的碳酸丙烯酯成品。
第二，催化剂和助催化剂具有协同催化的效果。二氧化碳结构稳定，C-O双键连接比较牢固，需要较高的活化能才能使双键断裂，而环氧丙烷性质比较活泼，比较容易开环，在催化剂的作用下，环氧丙烷的开环反应比较迅速，而二氧化碳的C-O双键断裂速度较慢，因此环加成反应速率主要由二氧化碳的C-O双键断裂速率决定。助催化剂能够使得催化剂与二氧化碳及环氧丙烷更加互溶，并能够加快二氧化碳的C-O双键断裂速度，更好的起到了催化效果，使反应更加迅速高效，从而提高环氧丙烷转化率。
第三，由于催化剂和助催化剂协同具有极佳的催化效果，二氧化碳及环氧丙烷的反应速率较高，故无需较高的反应温度及压力，可以采用温和的反应温度及压力，来降低对设备、仪表的要求，减少设备投资，降低耗能，降低生产过程控制的危险性。而且，温和的反应温度及压力，能够避免反应物在反应过程中分解或生成副产物，从而提高碳酸丙烯酯的生成率。
一实施方式，所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂的质量比例为1:(1～3):(0.005～0.03):(0.005～0.03)。例如，环氧丙烷、 二氧化碳、催化剂及助催化剂的质量比例为1:2:0.01:0.012。需要说明的是，催化剂和助催化剂的用量直接决定着环氧丙烷和二氧化碳的反应速度，进而决定着碳酸丙烯酯的产率，碳酸丙烯酯的产率随着催化剂及助催化剂的质量增大而增大，但是，碳酸丙烯酯的产率增加的幅度小于催化剂及助催化剂增加的幅度，且当催化剂及助催化剂与环氧丙烷的质量比例为1:0.005：0.005时，碳酸丙烯酯的产率为85.8％；当催化剂及助催化剂与环氧丙烷的质量比例为1:0.03：0.03时，碳酸丙烯酯的产率为99.8％；在此比例上再增加催化剂及助催化剂的用量，碳酸丙烯酯的产率几乎无变化。故环氧丙烷、二氧化碳、催化剂及助催化剂的质量比例为1:(1～3):(0.005～0.03):(0.005～0.03)时，可以达到较佳的催化效果。
一实施方式，所述催化剂为溴化钾、溴化钠、碘化钠和碘化钾中至少一种。例如，催化剂为溴化钾、溴化钠、碘化钠和碘化钾的共同混合物。例如，催化剂为溴化钾、溴化钠、碘化钠或者碘化钾。需要说明的是，这些离子液对碳烯环加成反应具有良好的催化效果。
一实施方式，所述将环氧丙烷、二氧化碳、催化剂及助催化剂通入至反应塔内的操作具体包括：将催化剂配置为饱和溶液，将多孔载体浸泡在所述饱和溶液内，接着进行烘干操作，得到催化固定床；将将环氧丙烷、二氧化碳、所述催化固定床及助催化剂通入至反应塔内。其中，所述多孔载体为氧化铝多孔颗粒、氧化锌多孔颗粒、氧化铬多孔颗粒、氧化镉多孔颗粒、氧化钴多孔颗粒、氧化镍多孔颗粒、氧化钼多孔颗粒或者氧化锡多孔颗粒。例如，多孔载体为氧化铝多孔颗粒。所述多孔载体的直径为2mm～4mm。例如，多孔载体的直径为3mm。所述浸泡时间为40～60小时。例如，浸泡时间为48小时。所述烘干操作的温度为140℃～160℃，时间为5～7小时。例如，烘干操作的温度为150℃，时间为6小时。需要说明的是，相对于液体催化剂，催化固定床的孔隙能够容纳二氧化碳及环氧丙烷，作为二氧化碳及环氧丙烷的催化固定床，能够增加二者的接触时间和接触面积，从而加快反应速度，增加碳酸丙烯酯的产率。
一实施方式，所述助催化剂包括促融催化剂及相转移催化剂，所述促融催化剂与所述相转移催化剂的质量比例为1:(1～3)。例如，助催化剂包括聚乙二醇和四丁基溴化铵，聚乙二醇与四丁基溴化铵的质量比例为5:7。需要说明的是，聚乙二醇与四丁基溴化铵的质量比例尤为重要，若聚乙二醇的质量比例较低，则可能影响催化剂与四丁基溴化铵的互溶性，进而影响到四丁基溴化铵对催化剂的协同促进效果。若四丁基溴化铵的质量比例较低，则会直接影响催化剂的离子反应活性，进而影响到二氧化碳与环氧丙烷的反应速度。
一实施方式，所述促融催化剂为聚乙二醇和聚乙二醇脂肪酸中至少一种，所述相转移催化剂为四丁基溴化铵、苯甲基三乙基氯化铵、三辛基甲基氯化铵、四丙基氯化铵、四甲基溴化铵、四丁基碘化铵、三乙基己基溴化铵和三乙基辛基溴化铵中至少一种。例如，促融催化剂为聚乙二醇和聚 乙二醇脂肪酸的共同混合物。例如，促融催化剂为聚乙二醇或者聚乙二醇脂肪酸。例如，相转移催化剂为四丁基溴化铵、苯甲基三乙基氯化铵、三辛基甲基氯化铵、四丙基氯化铵、四甲基溴化铵、四丁基碘化铵、三乙基己基溴化铵和三乙基辛基溴化铵的共同混合物。例如，相转移催化剂为四丁基溴化铵、苯甲基三乙基氯化铵、三辛基甲基氯化铵、四丙基氯化铵、四甲基溴化铵、四丁基碘化铵、三乙基己基溴化铵或者三乙基辛基溴化铵。需要说明的是，上述相转移催化剂能将无机的二氧化碳转移到有机的环氧丙烷上，能够增大催化剂的离子反应活性，加快二氧化碳与环氧丙烷的反应速度。上述促融催化剂是优良的化学促融剂，能够使得催化剂以及上述相转移催化剂溶解在一起，能够使得催化剂与二氧化碳及环氧丙烷更加互溶，从而促进催化剂的催化效果。
一实施方式，所述气液分离操作包括第一次气液分离操作及第二次气液分离操作，所述第一次气液分离操作的温度为60℃～80℃，所述第二次气液分离操作的温度为105℃～150℃。所述蒸馏操作的温度为230℃～240℃，压力为0.01MPa～0.05MPa。需要说明的是，碳酸丙烯酯的常压沸点为240℃，催化剂和促融催化剂的沸点都高于碳酸丙烯酯，相转移催化剂的沸点为100℃左右。当温度为60℃～80℃时，环氧丙烷和二氧化碳一起，与液相的催化剂、促融催化剂、相转移催化剂及碳酸丙烯酯分离；当温度为105℃～150℃时，相转移催化剂转化为气相，与液相的催化剂、促融催化剂及碳酸丙烯酯分离。因此，气液分离操作得到的混合气体除了环氧丙烷和二氧化碳之外，还含有相转移催化剂。当温度为230℃～240℃，压力为0.01MPa～0.05MPa时，碳酸丙烯酯由液相转化为气相，与液相的催化剂和促融催化剂分离。
一实施方式，在所述环加成反应时，还将所述混合气体及所述循环催化浓缩液，连同所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂一并通入至所述反应塔内。需要说明的是，将混合气体回收至反应塔内，从而降低二氧化碳成本以及减少温室气体排放。另外，将循环催化浓缩液回收至反应塔内，从而降低催化剂成本。
一实施方式，在将所述含酯气液混合物通入至所述分离器的操作之前，还将所述含酯气液混合物通入至换热器内，进行换热操作，以使所述换热器内的流通介质吸收所述含酯气液混合物内的热量。需要说明的是，换热器内的流通介质为未通入反应塔的环氧丙烷，通过换热器将环氧丙烷与含酯气液混合物进行热量交换，如此，通过对反应热的回收利用，来升高环氧丙烷的进入反应塔前的初始温度，以及降低含酯气液混合物分离前的初始温度，从而缩短环氧丙烷的加热时间和反应混合物的冷却时间，进而降低能耗。
一实施方式，在得到所述碳酸丙烯酯成品的操作之后，还将所述碳酸丙烯酯成品通入至冷凝器内，进行冷凝操作，以使所述碳酸丙烯酯成品的温度降至25℃～35℃。需要说明的是，由冷凝器对碳酸丙烯酯成品进行 冷凝操作，将碳酸丙烯酯成品的温度降至常温，以使碳酸丙烯酯成品由气相转换为液相。
一实施方式，在将所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂通入至所述反应塔内的操作之前，还将所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂通入至预热器内，进行预热操作，以使所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂的温度升高至130℃～150℃。如此，可使得环氧丙烷、二氧化碳、催化剂及助催化剂在进入反应塔之前即到达环加成反应温度，使得环加成反应的反应条件更加稳定，反应更加稳定。
与现有技术相比，本发明至少具有以下优点：
1、本方法通过对碳酸丙烯酯的制备、分离及提纯，能够得到纯度较高的碳酸丙烯酯成品；且采用温和的反应温度及压力，能够避免反应物在反应过程中分解或生成副产物，从而提高碳酸丙烯酯的生成率；且通过催化剂与助催化剂的协同催化，能够加快二氧化碳的C-O双键断裂速度，更好的起到了催化效果，使反应更加迅速高效，从而提高环氧丙烷转化率。
2、本方法通过合适的环氧丙烷、二氧化碳、催化剂及助催化剂的质量比例，可以达到较佳的催化效果。
3、本方法采用相转移催化剂和促融催化剂，通过相转移催化剂能将无机的二氧化碳转移到有机的环氧丙烷上，能够增大催化剂的离子反应活性，加快二氧化碳与环氧丙烷的反应速度；通过促融催化剂能够使得催化剂以及上述相转移催化剂溶解在一起，能够使得催化剂与二氧化碳及环氧丙烷更加互溶，从而促进催化剂的催化效果。
请一并参阅图2及图3，以下是应用基于二氧化碳原料的碳酸丙烯酯制备方法的碳酸丙烯酯制备装置部分。
一实施方式，请一并参阅图2及图3，一种应用基于二氧化碳原料的碳酸丙烯酯制备方法的碳酸丙烯酯制备装置10，包括进出料组件110、反应组件120、分离组件130、蒸馏组件140、冷凝组件150及碳酸丙烯酯成品储存罐160。所述进出料组件110包括二氧化碳通入管111、催化剂通入管112、环氧丙烷流入管113及换热器114，所述换热器114内设置有相互隔离的第一换热腔体及第二换热腔体，所述环氧丙烷流入管113与所述第一换热腔体连通。所述反应组件120包括反应塔121及反应混合物流出管122，所述反应塔121包括上封头、塔身及下封头，所述上封头及所述下封头分别与所述塔身连接，所述下封头分别与所述二氧化碳通入管111、所述催化剂通入管112及所述第一换热腔体连通，所述反应混合物流出管122的第一端与所述上封头连通，所述反应混合物流出管122的第二端与所述第二换热腔体连通。所述分离组件130包括分离器组131、二氧化碳流出管132及碳酸丙烯酯粗品流出管133，所述分离器组131与所述第二换热腔体连通，所述分离器组131的顶部与所述二氧化碳流出管132连通，所述分离器组131的底部与所述碳酸丙烯酯粗品流出管133的 第一端连通。所述蒸馏组件140包括蒸馏塔141、碳酸丙烯酯成品流出管142及催化剂流出管143，所述蒸馏塔141与所述碳酸丙烯酯粗品流出管133的第二端连通，所述蒸馏塔141的顶部与所述碳酸丙烯酯成品流出管142的第一端连通，所述蒸馏塔141的底部与所述催化剂流出管143连通。所述冷凝组件150包括冷凝器151及碳酸丙烯酯成品流通管152，所述冷凝器151的第一端与所述碳酸丙烯酯成品流出管142的第二端连通，所述冷凝器151的第二端与所述碳酸丙烯酯成品流通管152的第一端连通。所述碳酸丙烯酯成品储存罐160与所述碳酸丙烯酯成品流通管152的第二端连通。
对上述基于二氧化碳原料的碳酸丙烯酯制备装置10进行说明：以催化剂为碘化钾，助催化剂为聚乙二醇和四丁基溴化铵为例，环氧丙烷流入管113将待反应的环氧丙烷通入换热器114的第一换热腔体内，第二换热腔体用于盛装含酯气液混合物，第一换热腔体内的环氧丙烷与第二换热腔体的含酯气液混合物进行热量交换。在环氧丙烷吸收含酯气液混合物的热量后，将环氧丙烷通入反应塔121内，通过二氧化碳通入管111及催化剂通入管112，分别通入二氧化碳及催化剂，通过对反应塔121升温加压使其温度达到130℃～150℃，以及压力达到1.5MPa～1.8MPa。此时，二氧化碳为气相，环氧丙烷、催化剂和助催化剂为液相。二氧化碳和环氧丙烷在催化剂和助催化剂的协同催化下合成碳酸丙烯酯，得到含酯气液混合物。接着，反应混合物流出管122将含酯气液混合物通入分离器组131内，通过对分离器降温使其温度达到105℃～150℃，对含酯气液混合物进行气液分离操作。此时，环氧丙烷和四丁基溴化铵由液相转换为气相，连同二氧化碳，共同作为混合气体，从二氧化碳流出管132输出。碳酸丙烯酯、催化剂和聚乙二醇仍为液相，共同作为含酯混合液，从碳酸丙烯酯粗品流出管133通入蒸馏塔141内。接着，通过对蒸馏塔141升温加压使其温度达到230℃～240℃，压力达到0.01MPa～0.05MPa，对含酯混合液进行蒸馏操作。催化剂和聚乙二醇仍为液相，共同作为循环催化浓缩液，留在蒸馏塔141内。碳酸丙烯酯的常压沸点为240℃，在此高温高压条件下转换为气相，作为碳酸丙烯酯成品，从碳酸丙烯酯成品流出管142通入冷凝器151内。接着，由冷凝器151对碳酸丙烯酯成品进行冷凝操作，将碳酸丙烯酯成品的温度降至常温，以使碳酸丙烯酯成品由气相转换为液相。然后，碳酸丙烯酯成品流通管152将冷凝后的碳酸丙烯酯成品通入碳酸丙烯酯成品储存罐160内进行储存。如此，可以得到碳酸丙烯酯纯度在99％以上的碳酸丙烯酯成品。
另外，需要说明的是，通过换热器114将环氧丙烷与含酯气液混合物进行热量交换，如此，通过对反应热的回收利用，来升高环氧丙烷的进入反应塔121前的初始温度，以及降低含酯气液混合物分离前的初始温度，从而缩短环氧丙烷的加热时间和含酯气液混合物的冷却时间，进而降低能耗。
进一步地，请一并参阅图2及图3，所述进出料组件110还包括二氧化碳加热器115，所述二氧化碳加热器115设置于所述二氧化碳通入管111上。需要说明的是，通过二氧化碳加热器115将二氧化碳的温度升高至130℃～150℃。
进一步地，请一并参阅图2及图3，所述进出料组件110还包括环氧丙烷加压泵116，所述环氧丙烷加压泵116与所述环氧丙烷流入管113远离所述第一换热腔体的一端连通。需要说明的是，环氧丙烷加压泵116可以增高环氧丙烷流体的压力，避免其因压力不足而无法进入反应塔121，还可以控制环氧丙烷的流速，进而控制反应时环氧丙烷的用量。
进一步地，请一并参阅图2及图3，所述进出料组件110还包括环氧丙烷过渡连接管117，所述环氧丙烷过渡连接管117分别与所述下封头及所述第一换热腔体连通。所述进出料组件110还包括环氧丙烷加热器118，所述环氧丙烷加热器118设置于所述环氧丙烷过渡连接管117上。需要说明的是，通过环氧丙烷加热器118将换热后的环氧丙烷的温度升高至130℃～150℃。
进一步地，请一并参阅图2及图3，所述分离器组131包括一级分离器1311、二级分离器1312、四丁基溴化铵流出管1313。所述一级分离器1311与所述第二换热腔体连通，所述二级分离器1312与所述一级分离器1311连通，所述一级分离器1311的顶部与所述二氧化碳流出管132连通，所述四丁基溴化铵流出管1313的第一端与所述二级分离器1312的顶部连通，所述四丁基溴化铵流出管1313的第二端与所述二氧化碳流出管132连通，所述二级分离器1312组131的底部与所述碳酸丙烯酯粗品流出管133的第一端连通。需要说明的是，以催化剂为碘化钾，助催化剂为聚乙二醇和四丁基溴化铵为例，将一级分离器1311的温度控制在60℃～80℃，通过二氧化碳流出管132排去含酯气液混合物中的二氧化碳和环氧丙烷。再将二级分离器1312温度控制在105℃～150℃，通过四丁基溴化铵流出管1313排去四丁基溴化铵，使得含酯气液混合物中只剩下碘化钾、聚乙二醇及碳酸丙烯酯。如此，才可以保证蒸馏操作的有效进行，从而保证碳酸丙烯酯成品的纯度。
进一步地，请一并参阅图2及图3，所述蒸馏组件140还包括蒸汽发生器144，所述蒸汽发生器144与所述蒸馏塔141连通。需要说明的是，蒸汽发生器144为蒸馏塔141提供高温蒸汽，来使得蒸馏塔141的温度升高至230℃～240℃。
进一步地，请一并参阅图2及图3，所述分离组件130还包括二氧化碳回流管134，所述二氧化碳回流管134的第一端与所述二氧化碳流出管132连通，所述二氧化碳回流管134的第二端与所述二氧化碳通入管111连通。需要说明的是，二氧化碳回流管134能够将二氧化碳及环氧丙烷回收至反应塔121内，从而降低二氧化碳成本以及减少温室气体排放。
进一步地，请一并参阅图2及图3，所述蒸馏组件140还包括催化剂 回流管145，所述催化剂回流管145的第一端与所述催化剂流出管143连通，所述催化剂回流管145的第二端与所述催化剂通入管112连通。需要说明的是，催化剂回流管145能够将催化剂及部分助催化剂回收至反应塔121内，从而降低催化剂成本。
进一步地，请一并参阅图2及图3，所述冷凝组件150还包括碳酸丙烯酯成品回流管153，所述碳酸丙烯酯成品回流管153的第一端与所述冷凝器151的第二端连通，所述碳酸丙烯酯成品回流管153的第二端与所述蒸馏塔141流通。需要说明的是，蒸馏塔141内的温度为230℃～240℃，而反应塔121需要的反应温度为130℃～150℃，故催化剂及部分助催化剂在回收通入反应塔121前，需要进行降温，相比于再增设一台冷凝器151对催化剂及部分助催化剂进行降温，本发明是通过碳酸丙烯酯成品回流管153将一部分冷凝后的碳酸丙烯酯成品回流至蒸馏塔141内，与蒸馏塔141内的催化剂及部分助催化剂进行换热，以使催化剂及部分助催化剂的温度降至130℃～150℃，再回收至反应塔121内，如此，在达到对回收前的催化剂及部分助催化剂进行冷凝的功能的同时，还可以降低设备成本以及设备占地面积。[0068]请一并参阅图4、图5及图6，以下是碳酸丙烯酯制备装置的反应塔部分。
一实施方式，请一并参阅图4、图5及图6，一种碳酸丙烯酯制备装置的反应塔10，包括塔体110、塔板组件120及网环填充组件130。所述塔体110包括上封头111、塔身112及下封头113，所述上封头111及所述下封头113分别与所述塔身112的两端连接，所述下封头113开设有二氧化碳进料口1131、环氧丙烷进料口1132及催化剂进料口1133，所述塔身112内部设置有反应腔体1121，所述上封头111开设有碳酸丙烯酯出料口1111。所述塔板组件120设置于所述反应腔体1121内，所述塔板组件120包括多组错位塔板121，每一组所述错位塔板121包括第一塔板1211及第二塔板1212，所述第一塔板1211与所述塔身112内壁相固定，所述第一塔板1211包括第一实体区1211a及第一流通区1211b，所述第二塔板1212与所述塔身112内壁相固定，所述第二塔板1212包括第二实体区1212a及第二流通区1212b，所述第一实体区1211a面向所述第二流通区1212b设置，所述第二实体区1212a面向所述第一流通区1211b设置，所述第一流通区1211b开设有多个第一流通孔1211b1，各所述第一流通孔1211b1分别与所述第一塔板1211及所述第二塔板1212之间围成的反应隔区连通，所述第二流通区1212b开设有多个第二所述流通孔，各所述第二流通孔分别与所述第一塔板1211及所述第二塔板1212之间围成的所述反应隔区连通。所述网环填充组件130包括多个网环组131，多个所述网环组131均填充于反应腔体1121内，每一所述网环组131对应填充于一所述反应隔区内。
需要说明的是，请参阅图5，通过二氧化碳进料口、环氧丙烷进料口及催化剂进料口分别将二氧化碳、环氧丙烷、催化剂及助催化剂从塔体的 底部通入反应腔体，其中，二氧化碳、环氧丙烷、催化剂及助催化剂共同作为反应物料。二氧化碳和环氧丙烷在催化剂的催化下发生环加成反应转化为碳酸丙烯酯。环加成反应为高温高压，通过对反应塔升温加压使得反应腔体的温度压力达到反应条件。例如，反应条件为130℃～150℃的温度条件，以及1.5MPa～1.8MPa的压力条件，此时二氧化碳为气相，环氧丙烷、催化剂及助催化剂为液相。这些反应物料会沿着塔板的第一流通孔及第二流通孔折流交替上升，相对于直流上升，会降低反应物料的流速，从而增加了反应物料之间的接触时间和接触面积，进而使得反应物料之间的反应更完全，转化率更高。
另外需要说明的是，环氧丙烷、催化剂及助催化剂为液相，密度较大，上升过程速度相对较慢，一般聚集在塔板面上部分，而二氧化碳为气相，密度小，上升的速度较快，一般聚集在第一塔板与第二塔板之间的中上部，即反应隔区的中上部，当二氧化碳气体在上升过程中碰到网环组时，被网环改变前进方向，向下分散冲向环氧丙烷、催化剂及助催化剂之间，从而使反应物料之间充分混和，提高反应收率。
进一步地，所述反应塔体的内径为50mm～70mm，所述反应塔体的长度为800mm～1200mm。
进一步地，请参阅图4，所述下封头113与所述反应腔体1121之间设置有进料混合腔体1134，所述上封头111与所述反应腔体1121之间设置有出料混合腔体1112。需要说明的是，在高温高压的反应条件下，进料混合腔体及出料混合腔体能够暂时存放反应物料及反应产物，避免反应塔由于压强原因导致过多的反应物料压入反应腔体以及过多的反应产物压出反应腔体，从而出现喷射泄漏气液的现象。
进一步地，请参阅图4，所述网环组131包括多个网环1311。所述网环包括第一网环体及第二网环体，所述第二网环体设置于所述第一网环体内且与所述第一网环体连接，所述第一网环体开设有多个第一网孔，所述第二网环体开设有多个第二网孔，所述第一网孔位于相邻两个所述第二网孔之间，所述第二网孔位于相邻两个所述第一网孔之间。需要说明的是，第一网环体与第二网环体的错位网孔，增加了反应物料的流动路径，能够降低反应物料的流速，从而增加了反应物料之间的接触时间和接触面积，进而使得反应物料之间的反应更完全，转化率更高。
进一步地，所述网环的直径为2mm～4mm。如此，合适的网环的直径会使得反应物料的流速较为合适。
进一步地，所述第一塔板为圆板状结构，所述第一实体区与第一流通区的面积相等。所述第二塔板为圆板状结构，所述第二实体区与第二流通区的面积相等。所述第一实体区与第一流通区之间的界线为直线。如此，使得实体区与流通区的区域面积分配较为合理。
进一步地，每相邻两个所述第一流通孔之间的距离相等。每相邻两个所述第二流通孔之间的距离相等。如此，使得第一流通孔及第二流通孔均 匀间隔排列。
进一步地，所述第一流通孔的直径为0.5mm～2mm；所述第二流通孔的直径为0.5mm～2mm。例如，第一流通孔的直径为0.5mm、1mm、1.5mm或者2mm；第二流通孔的直径为0.5mm、1mm、1.5mm或者2mm。需要说明的是，流通孔的直径太大会使通过流通孔的反应物料的股流太大，不利于反应物料之间相充分接触；流通孔直径太小，会使得反应物料无法通过。经过无数实验和实践证明，流通孔的直径以0.5mm～2mm为宜。
进一步地，每一个所述第一塔板的第一流通孔的总面积与所述二氧化碳进料口、所述环氧丙烷进料口及所述催化剂进料口的总面积之比为20:1。每一个所述第二塔板的第一流通孔的总面积与所述二氧化碳进料口、所述环氧丙烷进料口及所述催化剂进料口的总面积之比为20:1。需要说明的是，如此能够保证足够大的流通孔面积来降低反应物料的流速，从而增大反应物料之间的接触面积及接触时间，进而使反应物料之间充分接触。
以下是基于二氧化碳原料的碳酸丙烯酯制备方法的具体实施例部分。
实施例1
S111，在130℃的温度条件下，以及1.5MPa的压力条件下，将10kg环氧丙烷、10kg二氧化碳、0.05kg碘化钾、0.02kg聚乙二醇和0.03kg四丁基溴化铵通入至反应塔内，发生环加成反应后，得到含酯气液混合物。
S121，将所述含酯气液混合物通入至分离器内，在60℃的温度条件下，进行第一次气液分离操作，以及在105℃的温度条件下，进行第二次气液分离操作，共同得到混合气体及含酯混合液。
S131，在230℃的温度条件下，以及0.01MPa的压力条件下，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到实施例1的碳酸丙烯酯成品及循环催化浓缩液。其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
实施例2
S112，在150℃的温度条件下，以及1.8MPa的压力条件下，将10kg环氧丙烷、30kg二氧化碳、0.3kg碘化钾、0.12kg聚乙二醇和0.18kg四丁基溴化铵通入至反应塔内，发生环加成反应后，得到含酯气液混合物。
S122，将所述含酯气液混合物通入至分离器内，在80℃的温度条件下，进行第一次气液分离操作，以及在150℃的温度条件下，进行第二次气液分离操作，共同得到混合气体及含酯混合液。
S133，在240℃的温度条件下，以及0.05MPa的压力条件下，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到实施例2的碳酸丙烯酯成品及循环催化浓缩液。其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
实施例3
S113，在140℃的温度条件下，以及1.6MPa的压力条件下，将10kg 环氧丙烷、20kg二氧化碳、0.1kg碘化钾、0.05kg聚乙二醇和0.07kg四丁基溴化铵通入至反应塔内，发生环加成反应后，得到含酯气液混合物。
S123，将所述含酯气液混合物通入至分离器内，在70℃的温度条件下，进行第一次气液分离操作，以及在110℃的温度条件下，进行第二次气液分离操作，共同得到混合气体及含酯混合液。
S133，在235℃的温度条件下，以及0.03MPa的压力条件下，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到实施例3的碳酸丙烯酯成品及循环催化浓缩液。其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
实施例4
S114，在140℃的温度条件下，以及1.6MPa的压力条件下，将10kg环氧丙烷、25kg二氧化碳、0.1kg溴化钾、0.05kg聚乙二醇脂肪酸和0.07kg苯甲基三乙基氯化铵通入至反应塔内，发生环加成反应后，得到含酯气液混合物。
S124，将所述含酯气液混合物通入至分离器内，在70℃的温度条件下，进行第一次气液分离操作，以及在130℃的温度条件下，进行第二次气液分离操作，共同得到混合气体及含酯混合液。
S134，在235℃的温度条件下，以及0.03MPa的压力条件下，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到实施例4的碳酸丙烯酯成品及循环催化浓缩液。其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
对比例1
在140℃的温度条件下，以及1.6MPa的压力条件下，将10kg环氧丙烷、20kg二氧化碳和0.1kg碘化钾通入至反应塔内，发生环加成反应后，得到含酯气液混合物，将含酯气液混合物中的二氧化碳排去，得到对比例1的碳酸丙烯酯成品。
对比例2
在280℃的温度条件下，以及6MPa的压力条件下，将10kg环氧丙烷、20kg二氧化碳、0.01kg碘化钾、3kg聚乙二醇和5kg四丁基溴化铵通入至反应塔内，发生环加成反应后，得到含酯气液混合物。
在50℃的温度条件下，将所述含酯气液混合物通入至分离器内，进行气液分离操作，得到混合气体及含酯混合液。
在150℃的温度条件下，以及0.03MPa的压力条件下，将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到对比例2的碳酸丙烯酯成品及循环催化浓缩液。其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
对实施例1、实施例2、实施例3、实施例4、对比例1及对比例2的碳酸丙烯酯成品，分别用气相色谱法测定其组成，并计算
实施例3、对比例1及对比例2进行环氧丙烷转化率和碳酸丙烯酯成 品的纯度，结果如表1所示。
表1
测试项目 环氧丙烷转化率(％) 碳酸丙烯酯成品的纯度(％)
实施例1 85.8 100.0
实施例2 99.8 100.0
实施例3 99.2 100.0
实施例4 98.3 100.0
对比例1 76.5 82.8
对比例2 68.6 71.2
根据上表进行分析：相对于实施例1、实施例2、实施例3及实施例4，对比1没有采用助催化剂，导致环氧丙烷转化率偏低；对比1没有对含酯气液混合物进行分离提纯，导致碳酸丙烯酯成品的纯度偏低。
对比例2虽然提高了环加成反应的温度压力，但是，采用的催化剂的用量偏低，以及助催化剂的用量偏高，导致环氧丙烷转化率偏低；对比例2虽然对含酯气液混合物进行分离提纯，但是，在80℃的温度条件下，四丁基溴化铵为液相，留在含酯混合液内；在150℃的温度条件下，以及0.03MPa的压力条件下，碳酸丙烯酯无法与聚乙二醇分离，导致碳酸丙烯酯成品的纯度偏低。
由此可见，助催化剂与催化剂的协同催化可以使反应更加迅速高效，从而提高环氧丙烷转化率。助催化剂与催化剂的质量比例会严重影响二者的催化效果。对含酯气液混合物进行分离提纯，可以很大程度提高碳酸丙烯酯成品的纯度。分离提纯的温度及压力会严重影响分离提纯的有效性。
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。

Claims (10)

  1. 一种基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，包括以下步骤：在130℃～150℃的温度条件下，以及1.5MPa～1.8MPa的压力条件下，将环氧丙烷、二氧化碳、催化剂及助催化剂通入至反应塔内，发生环加成反应后，得到含酯气液混合物；将所述含酯气液混合物通入至分离器内，进行气液分离操作，得到混合气体及含酯混合液；
    将所述含酯混合液通入至蒸馏塔内，进行蒸馏操作，得到碳酸丙烯酯成品及循环催化浓缩液，其中，所述循环催化浓缩液包括所述催化剂及所述助催化剂。
  2. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂的质量比例为1:(1～3):(0.005～0.03):(0.005～0.03)。
  3. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，所述催化剂为溴化钾、溴化钠、碘化钠和碘化钾中至少一种。
  4. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，所述助催化剂包括促融催化剂及相转移催化剂，所述促融催化剂与所述相转移催化剂的质量比例为1:(1～3)。
  5. 根据权利要求4所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，所述促融催化剂为聚乙二醇和聚乙二醇脂肪酸中至少一种，所述相转移催化剂为四丁基溴化铵、苯甲基三乙基氯化铵、三辛基甲基氯化铵、四丙基氯化铵、四甲基溴化铵、四丁基碘化铵、三乙基己基溴化铵和三乙基辛基溴化铵中至少一种。
  6. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，所述气液分离操作包括第一次气液分离操作及第二次气液分离操作，所述第一次气液分离操作的温度为60℃～80℃，所述第二次气液分离操作的温度为105℃～150℃；所述蒸馏操作的温度为230℃～240℃，压力为0.01MPa～0.05MPa。
  7. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，在所述环加成反应时，还将所述混合气体及所述循环催化浓缩液，连同所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂一并通入至所述反应塔内。
  8. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，在将所述含酯气液混合物通入至所述分离器的操作之前，还将所述含酯气液混合物通入至换热器内，进行换热操作，以使所述换热器内的流通介质吸收所述含酯气液混合物内的热量。
  9. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，在得到所述碳酸丙烯酯成品的操作之后，还将所述碳酸丙烯 酯成品通入至冷凝器内，进行冷凝操作，以使所述碳酸丙烯酯成品的温度降至25℃～35℃。
  10. 根据权利要求1所述的基于二氧化碳原料的碳酸丙烯酯制备方法，其特征在于，在将所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂通入至所述反应塔内的操作之前，还将所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂通入至预热器内，进行预热操作，以使所述环氧丙烷、所述二氧化碳、所述催化剂及所述助催化剂的温度升高至130℃～150℃。
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