Method for producing 1,2-dichloroethane
(57) Abstract:The object of the invention is a method for producing 1,2-dichloroethane by catalytic interaction of ethylene with chlorine at an elevated temperature on the catalyst consisting of sodium chloride and iron chloride (III) in a molar ratio of 0.05: 1 to 0.48: 1, in an inert organic solvent, followed by separation of the target product, and the process is carried out while maintaining the specified molar ratio of sodium chloride and iron chloride (III). Preferably in an inert organic solvent used circulating 1,2-dichloroethane, and the process is conducted in an atmosphere of inert gas at a temperature of 70 - 90oC and a pressure of 1.4 to 1.6 bar. The method allows to significantly reduce the formation of undesirable 1,1,2-trichloroethane. 6 C.p. f-crystals, 1 tab., 1 Il. The invention relates to a technology for chlorinated aliphatic hydrocarbons, in particular to a method for producing 1,2-dichloroethane.The known method for producing 1,2-dichloroethane by reacting ethylene with chlorine in the reaction medium at a temperature of 30 - 100oC catalyst consisting of sodium chloride and iron chloride (III) in mosnum shown in the prototype examples of the process is carried out at a temperature of 50oC and a pressure of 1.8 bar, and comparative experience, which operate at a molar ratio of ferric chloride and sodium chloride is 1:0,33, that is, when the molar ratio is below 1: 0,5. The degree of purity of the 1,2-dichloroethane is 99.9%, and the content of by-product, 1,1,2-trichloroethane, - 0,090%.The objective of the invention is the presentation of the method for producing 1,2-dichloroethane, providing reduced formation of undesirable 1,1,2-trichloroethane.This problem is solved in a method of producing 1,2-dichloroethane by catalytic interaction of ethylene with chlorine in the reaction medium at an elevated temperature on the catalyst consisting of sodium chloride and iron chloride (III) in a molar ratio of 0.05 - 0,48) : 1, followed by separation of the target product, due to the fact that the process is carried out while maintaining the specified molar ratio of sodium chloride and iron chloride (III) constant.As reaction medium preferably used liquid target product, i.e. circulating 1,2-dichloroethane, and the reagents added to the circulating 1,2-dichloroethane. There is no need to use chlorine in liquid form, taiah, what can I use chlorine gas. For example, the pressure is preferably at most 1 bar excess pressure, preferably between 0.4 and 0.6 bar overpressure, which is mainly set by creating an atmosphere of inert gas, preferably nitrogen.The reaction temperature is 60 - 120oC, preferably 65 - 105oC, in particular 70 - 90oC. the Pressure and temperature coordinates so that the reaction was carried out below the boiling point of 1,2-dichloroethane.According to a preferred variant of the proposed method 1,2-dichloroethane completely or preferably partially (5 - 80%) served in the capacity of the low pressure, thus warded off the product is separated and the residual 1,2-dichloroethane recycle in the process. The enthalpy of the stream of 1,2-dichloroethane causes the evaporation of part of 1,2-dichloroethane. Evaporated 1,2-dichloroethane does not contain catalyst and after condensation has purity, comprising at least 99.9 percent. Thus it can directly apply for the cleavage reaction to vinyl chloride. From clean water to separate the catalyst, as well as from follow-up are required drying 1,2-dichloroethane by distillation required in TSA.Vessel pressure low pressure expedient is 0.2 - 0.7 bar abs. This low pressure create and maintain using standard blower units or pumps, which in the following are referred to as "vacuum pump". If the vacuum pump should not be used to supply gaseous 1,2-dichloroethane, the latter is subjected to condensation with a suitable device, which in the following is referred to as "cooler", and the condensate is collected in the tank.The use of the heat of reaction for the partial evaporation of 1,2-dichloroethane and the reaction takes place in the specified preferred range of temperatures cause significant economical cooling agent.Katalizatoriai 1,2-dichloroethane, not evaporated in the vessel with low pressure recycle in the cycle of 1,2-dichloroethane. This is possible due to the fact that during the reaction produces only small amounts of by-products and recycled 1,2-dichloroethane contains only a small amount of hydrogen chloride.The exhaust gas is practically free from chlorine. Particularly preferred variant implementation of the reaction, according to which the leash is pressure, has the advantage that an additional reactor to convert residual ethylene is not needed. However, in the case of this preferred variant of the proposed method can be applied to devices for separating and recycling of ethylene, as they do not require large expenditures.For example, you can further increase the yield of ethylene or reduce the loss of ethylene due to recirculation atlantabased flue gas tank with a low pressure after the vacuum pump using a suitable compressor, preferably jet compressor, it is installed on the bottom of the reactor, and re-interaction of ethylene with chlorine. As a working stream for the preferred compressor is mainly used part recycled 1,2-dichloroethane.The energy of the residual amounts of ethylene can, however, also be used in the combustion exhaust gas, primarily for the recovery of hydrogen chloride.The proposed method can be carried out in the unit, shown in the attached drawing.The apparatus comprises a reactor 1, lines 2 and 3, the feed of ethylene and chlorine, respectively, line 4 inert gas, line 5,La recycling not evaporated product, connected to the tank 9 and hosting the pump 10, line 11 for recycling part of the product with the pump 12, which leads to the cooler or heat exchanger 13.Line 7 for draining steam 1,2-dichlorethylene appropriate leads through the cooler 14 to the vacuum pump 15. The cooler 14, is supplied by a line 16 leading to the collector 17 of liquefied 1,2-dichloroethane.In addition, the installation preferably includes a line 18, which connects the pressure side of the vacuum pump 15 through the compressor 19 to the reactor 1.It is intended for recycling unreacted ethylene. Positions 20 and 21 of the marked line for the flue gas.As already mentioned, it is necessary to maintain constant the above ratio of sodium chloride and iron chloride (III) during the reaction. If, for example, due to corrosion in the installation gets chloride iron (III), shall be submitted to process the appropriate amount of sodium chloride, it is advisable from the tank 9, as the purity warded off 1,2-dichloroethane decreases or increases the amount of the formed by-product.The purity of the circulating 1,2-dichloroethane average swale. So usually there is no need for removal of the product to remove impurities.Examples 1-3. Direct chlorination is carried out in a reactor 1 with a capacity of 14.6 m3with the degree of filling, equal to 81%. By feeding an inert gas through line 4, the pressure is maintained at 0,54 bar excess pressure, and temperature at the 75oC. as the reaction medium used liquid 1,2-dichloroethane containing iron chloride (III), equal to 700 h/mill.In the reaction medium from the tank 9 serves sodium chloride to achieve the desired molar ratio of sodium chloride and iron chloride (III) (see the table below), this molar ratio is maintained throughout the reaction. In the reactor 1 by line 2 serves 2000 nm3/h of ethylene, and on line 3, the corresponding amount of gaseous chlorine. Part of the product serves on line 5 in capacity with low pressure 6 under a pressure of 0.3 bar abs. Here is evaporated 8,90 t/h 1,2-dichloroethane, which is devoting on line 7. Exhaust 1,2-dichloroethane free from catalyst and is specified in table a purity that allows direct processing of 1,2-dichloroethane to vinyl chloride. The table also shows the content side polyroot on lines 8 through the pump 10 into the reactor 1. The main product flow line 11 by pump 12 is fed to the line 8 and, if necessary, through the cooler 13, return to the reactor 1. 1. Method for producing 1,2-dichloroethane by catalytic interaction of ethylene with chlorine in the reaction medium at an elevated temperature on the catalyst consisting of sodium chloride and iron chloride (III) in a molar ratio of NaCl; FeCl3equal (0,05 - 0,48) : 1, followed by separation of the target product, wherein the process is carried out while maintaining the specified molar ratio of sodium chloride and iron chloride (III) constant.2. The method according to p. 1, wherein the process is carried out at a temperature of 70 - 90oC.3. The method according to PP.1 and 2, characterized in that the process is carried out at a pressure of 1.4 to 1.6 bar.4. The method according to p. 3, characterized in that the process is carried out in an atmosphere of inert gas.5. The method according to one or more of the paragraphs.1 to 4, characterized in that the target product, in whole or in part serves in the capacity of the low pressure, thus warded off the product is separated and the residual 1,2-dichloroethane recycle in the process.6. The method according to one or more of the paragraphs.The method according to one or more of the paragraphs.1 - 6, characterized in that the chlorine serves as a gas.
FIELD: industrial organic synthesis.
SUBSTANCE: invention is dealing with production of chlorohydrocarbons exhibiting plasticizing properties in polymer compositions in production of synthetic building materials, varnishes and paints, artificial films and leathers, in rubber industry, and as fire-retardant additives in polymers. Process comprises chlorination of waste obtained in production of C14-C32 fraction by ethylene-α-olefin oligomerization. Chlorination is accomplished in two steps: addition chlorination at 35-55°C followed by substitution chlorination at 40-105°C. Chlorohydrocarbons thus obtained can, in particular, be used as secondary plasticizer in polyvinylchloride compositions.
EFFECT: reduced expenses due to using production waste.
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