| 78.4% |
at 45 - 55℃; |
Example 1 In order to charge EC in a reactor 1, EC (m.p. 36-37), which is a colorless and odorless crystal at room temperature, must be melted into a transferable solution. 10.6 kg (120.37 mol) of EC solution were charged in a reaction compartment 8 while warm water was supplied to an external cooling water jacket of the reaction compartment 8 so as to maintain the reaction compartment 8 at 45-50. While warm water was supplied to the cooling water jacket so as to maintain the temperature of the reactor at 45-50, F2 gas generated from an F2 electrolytic bath was fed into a mixer (not shown) and then mixed with N2 gas to produce 20 v/v percent F2/N2 (F2 content was 20 v percent) mixture gas. F2/N2 mixture gas was fed through an F2/N2 mixture gas inlet 2 at a lower part of the reactor into the reactor at a flow rate of 1960 l/h. Additionally, F2/N2 mixture gas was fed through a gas bubble regulating column 3 into the reactor. Packings were packed in the gas bubble regulating column. In the present example, twelve hundred raschig rings were packed in the gas bubble regulating column. The four cylindrical gas bubble regulating columns 3 were provided, and each had an internal diameter of 2, a length of 600 mm, and an internal volume of 1373 cm3. When F2/N2 mixture gas passed through a raschig ring bed, which consisted of raschig rings irregularly packed in the column, the gas flowed through various flow paths and was uniformly dispersed. At this stage, if the flow rate of the mixture gas is regulated, it is possible to make the sizes of bubbles of F2/N2 mixture gas, which is formed in the EC liquid, fine using several gas bubble regulating columns. The sizes of the bubbles depend on the number of gas bubble regulating columns, the amount of packings, and the flow rate of F2/N2 mixture gas. The use of the gas bubble regulating column contributes to formation of the fine bubbles of F2/N2 mixture gas to be reacted with EC, and to uniform dispersion of the bubbles of F2/N2 mixture gas in EC liquid. The flow rate of mixture gas was controlled by a flow controller. When F2/N2 mixture gas was fed into the reactor and a reaction started to be conducted, the reaction was intensely conducted and high reaction heat was generated. Accordingly, cooling water was supplied to the cooling water jacket and a reaction temperature was maintained at 55+/-3. The arrows in the reactor shown in FIG. 1 denote the flow direction of EC. Brine at -15 was fed into a heat exchanger at an upper part of the reactor so as to maintain a temperature of a lower part of the heat exchanger at 27+/-2. A solenoid valve was provided at a pipe for discharging unreacted gases therethrough into an absorber and a device for controlling fine pressure was connected thereto so as to control the pressure in the reactor. The pressure was controlled to 1000+30 mmAq. When the flow rate of F2 gas was 1.2 mol based on EC charged in the reactor at an initial stage, the reaction was finished. After the end of the reaction, remaining gas was removed from the reactor using 500 L/hr N2 for 30 min. The reaction results were that the total amount of product was 13.14 kg, HF was 11.63 wt percent (1.05 kg), FEC was 75.37 wt percent (8.75 kg, 82.5 mol), and DFEC was 3.0 wt percent (0.35 kg, 2.85 mol). A mole number of reacted F2 was 88.2 mol, conversion efficiency of F2 was 61.1percent, and selectivity of FEC was 93.5percent. Yield of FEC was 57.1percent based on F2.; Example 2 The reaction was conducted under the same conditions as example 1 with the exception of the following conditions. Two reactors having the same shape were employed while being serially connected. 10.6 kg of EC solution were charged in a first reactor as a main reactor and in a second reactor, and 20 v/v percent F2/N2 mixture gas as reactant gas was fed into the first reactor to conduct a first reaction. Unreacted gases, which were generated in the first reaction, were fed into the second reactor so as to be reused. The other reaction conditions were the same as example 1. As a result, the total amount of product was 25.3 kg, HF was 9.96 wt percent (2.52 kg), FEC was 52.74 wt percent (12.01 kg, 113.2 mol), and DFEC was 2.06 wt percent (0.47 kg, 3.73 mol). A mol number of reacted F2 was 116.9 mol, which meant that conversion efficiency of F2 was 80.93percent, and selectivity of FEC was 96.8percent. Yield of FEC was 78.4percent based on F2.; Example 3 The reaction was conducted under the same conditions as example 2 with the exception of the following conditions. 10.6 kg of EC solution were charged in a first reactor as a main reactor, and 10.6 kg of EC/FEC solution, which contains 35 wt percent (34.8 mol) FEC, were charged in a second reactor. 20 v/v percent F2/N2 mixture gas as reactant gas was fed into the first reactor to conduct a first reaction. Unreacted gases, which were generated in the first reaction, were fed into the second reactor so as to be reused. The other reaction conditions were the same as example 2. As a result, the total amount of product was 25.01 kg, HF was 11.79 wt percent (2.95 kg), FEC was 73.65 wt percent (16.24 kg, 153.1 mol), and DFEC was 2.99 wt percent (0.66 kg, 5.32 mol). A mol number of reacted F2 was 124.8 mol, which meant that conversion efficiency of F2 was 86.4percent, and selectivity of FEC was 94.8percent. Yield of FEC was 81.9percent based on F2. Example 1 employed one reactor 1, but examples 2 and 3 employed two reactors 1 which were serially connected to each other. When two reactors were used, unreacted F2 gas, discharged from the first reactor, was recovered, provided to form F2/N2 mixture gas, and fed into the second reactor in the same manner as the first reactor. Compared to the use of one reactor, the use of two reactors is more effective to reduce the loss of F2 gas and to increase the amount of FEC produced. |
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