Method for producing 1,2-dichloroethane

 

(57) Abstract:

Usage: 1,2-dichloroethane is used as the solvent. Summary of the invention for producing 1,2-dichloroethane the process is conducted at a molar ratio of ethylene: chlorine 0,995 : 1,0 - 1,005 : 1,0, when the feed rate into the reactor chlorine containing 5,0 - 10,0% vol. oxygen, 300-900m3/h at a feed rate of ethylene 268-m3/h in the presence of 0.005 - 0.5 wt.% iron chloride (III) with 84 - 102C and a pressure of 1,0105-1,8105and exhaust gases from the stage of selection of 1,2-dichloroethane condensation miss at 40 - 80C in water of 1.0 - 5.0 wt. % solution of iron chloride (II), previously obtained by dissolving carbonate of iron (II) water of 3.0 - 10.0 wt.% the hydrochloric acid formed during the absorption of hydrogen chloride from the stage of purification of 1,2-dichloroethane raw. table 1.

The invention relates to chemical technology, in particular to a method of producing 1,2-dichloroethane, which is used as intermediate for the synthesis of vinyl chloride or solvent in organic synthesis.

The known method for producing 1,2-dichloroethane by oxychlorination process of ethylene using hydrogen chloride and air or oxygen with the addition of nitrogen at a temperature of 200-250o C 19/045, 17/156, publ. 1984).

The disadvantage of this method is the complexity of the process, the use of elevated temperature and pressure, the presence in the exhaust from the reactor the gases carbon monoxide, cooling the effluent from the reactor a gas mixture of aqueous solutions of caustic soda.

The known method for producing 1,2-dichloroethane by reacting ethylene and chlorine in the liquid phase at a temperature not lower than 83aboutIn the presence of a catalyst of iron chloride (III), an inhibitor of adverse reactions and oxygen, and released during the reaction heat is used to heat the cube columns for the separation of high-boiling components (see application Germany N 3604968, class C 07 C 19/045, published. 1986).

According to a known method in the reactor filled with EDC serves ethylene, chlorine mixed with oxygen (0.1 to 10 mol.%).As catalyst, use iron chloride (III). In reaction medium is injected 0.001 to 0.1 wt.% inhibitors adverse reactions, which use benzene, cresol, their derivatives, amines, etc. are Formed a pair of 1,2-dichloroethane in contact with the fluid in the contact zone, enter the heat exchanger, which is the reboiler of the distillation column, and nscontainerframe the ilen reacts with additional input by chlorine, and containing in pairs 1,2-dichloroethane is condensed and subsequently the rectification 1,2-dichloroethane raw.

The main disadvantage of this method is a multistage process. In addition, when disposing of ethylene some difficulties associated with the consumption control additional chlorine introduced into the second reactor, where it interacts excess of ethylene with chlorine.

It should be noted that the subsequent disposal of gases containing chlorine, ethylene, hydrogen chloride, oxygen, greatly complicates the process for producing 1,2-dichloroethane.

Closest to the invention to the technical essence and the achieved result is a method for producing 1,2-dichloroethane by chlorination of ethylene in the liquid phase in the presence of catalysts at a temperature of 90-160aboutC and a pressure of not less than 3 of 105PA, subsequent removal of catalysts, purification of 1,2-dichloroethane and gases (see application EPO N 113287, class C 07 C 19/045 17/02, publ. 1984).

According to a known method chlorine containing 0.2 to 3.0 wt.% oxygen and ethylene, Inuktitut in reaction medium containing 1,2-dichloroethane and the catalyst. As the catalyst used Gladilina and chlorine (1,01-1,2):1, the speed of injection of ethylene over 10 m/s and feed rate of chlorine 1-100 m/C. the catalyst from the 1,2-dichloroethane is separated by washing with water or by distillation or by precipitation with calcium carbonate or calcium hydroxide, and 1,2-dichloroethane, not containing water and catalyst, is subjected to rectification in a system composed of multiple columns. Exhaust gases manufacture of 1,2-dichloroethane was subjected to purification.

The main disadvantage of this method is the low quality of 1,2-dichloroethane raw, obtained in the production process (95,43-99,73 wt,%). A significant number of heavy chlorohydrocarbons (0.2-3.0 wt.% ) complicates the subsequent process of rectification of 1,2-dichloroethane and increases the cost of the target product.

In addition, the process for producing 1,2-dichloroethane is carried out in an excess of ethylene in order to prevent leakage of chlorine through the reactor and the introduction of its exhaust gases in the exhaust. This leads to increased consumption of ethylene, as the exhaust gases after separation of 1,2-dichloroethane, or subjected to dispersion in air or incinerated.

It should also be noted that the presence in the exhaust gases of the production of 1,2-dichloroethane ethylene mixed with oxygen and traces of chlorine increases pozarovzryvobezopasnost technologies water, containing hydrogen chloride, the remains of catalysts and other compounds, which are formed during the production of 1,2-dichloroethane.

The aim of the invention is to improve the quality of 1,2-dichloroethane raw, the reduction of consumption of ethylene, reduced pozarovzryvobezopasnost process for producing 1,2-dichloroethane.

This objective is achieved in that in the method for producing 1,2-dichloroethane by reacting ethylene with chlorine in the presence of oxygen and a catalyst - iron trichloride in liquid 1,2-dichloroethane at elevated temperature and pressure, the allocation of 1,2-dichloroethane condensation, purification of gases and 1,2-dichloroethane raw and subsequent rectification 1,2-dichloroethane, the process is carried out at a molar ratio of ethylene : chlorine 0,995:1,0-1,005: 1.0 at a feed rate of the chlorine into the reactor containing 5,0-10,0% vol. oxygen, 300-900 m3/h at a feed rate of ethylene 268-860 m3/h in the presence of 0.005-0.5 wt.% iron chloride (III) at a temperature of 84-102aboutAnd pressure 1,0105- 1,8105PA and the exhaust gases from the stage of selection of 1,2-dichloroethane condensation, miss at 40-80aboutThrough the water of 1.0-5.0 wt.% the solution of iron chloride (II), previously obtained by dissolving carbonate of iron (II) water of 3.0-10.0 wt.%-by the raw.

The process for producing 1,2-dichloroethane at a molar ratio of ethylene: chlorine 0,995:1 - 1,005:1 in the scientific and patent literature are not described, which is associated with significant difficulties separating unreacted chlorine from gases generated upon receipt of 1,2-dichloroethane raw.

The process for producing 1,2-dichloroethane at a molar ratio of ethylene : chlorine 0,995:1 - 1,005:1,0 allows to drastically reduce the consumption of ethylene in the production of 1,2-dichloroethane and reduce the ethylene content in the exhaust gases after the condensation of 1,2-dichloroethane to 1.0 vol.%. The content of chlorine and oxygen in the exhaust gases is not more than 0.001 and 5.0% vol. respectively.

Use in a method of producing 1,2-dichloroethane chlorine containing 5,0-10,0% vol. oxygen, can dramatically reduce the formation of by-products and to improve the quality of 1,2-dichloroethane raw.

Use in a method of producing 1,2-dichloroethane bandwidth gases after separation by condensation of 1,2-dichloroethane through the water of 1.0-5.0 wt.% the solution of iron chloride (II) at 40-80aboutWith in the scientific and patent literature are not described.

Use in a method of producing 1,2-dichloroethane transmission of gases through an aqueous solution of chlorite is> significantly absorbed oxygen, hydrogen chloride and flue gases are not inflammable.

An aqueous solution of iron chloride (II) is obtained by dissolution of carbonate of iron of 3.0-10.0 wt.% aqueous solution of hydrochloric acid, which is obtained by absorption of chloride Dorada after its separation from 1,2-dichloroethane raw cleanup phase.

Thus, the technical solution as a new set of essential features showing new technical property meets the criterion of "substantial differences".

The invention is illustrated by the following examples in which the above process parameters and properties of 1,2-dichloroethane raw and gases.

P R I m e R 1 (invention). In charator, which is a vertical cylindrical apparatus of stainless steel 12X18H10T with six perforated grilles to prevent vertical mixing volume 22 m3download 12000 kg 1,2-dichloroethane raw and in the lower part of the reactor through separate pipelines serves ethylene speed 805 m3/h and a pressure of 1105PA and chlorine containing 10 vol.% oxygen, with a speed of 900 m3/h and a pressure of 1105PA.

The molar soothes the e passage of the reaction between ethylene and chlorine, beginning in the mixing zone and terminating in the reaction zone, the reactor temperature is maintained at 84aboutC, and the excess heat released during the reaction is removed return 1,2-dichloroethane-raw, which enters the lower part of charator of gazorazdelitel after cooling and condensation of 1,2-dichloroethane from gases. Departing from charator gases are cooled in karabanovich refrigerators are cooled by a brine of sodium chloride with a temperature of 2-4aboutWith, and condensed 1,2-dichloroethane is separated from the gases in patristical and enters the lower part of charator. Exhaust gases with a temperature of less than 50aboutWith that contain traces of ethylene, chlorine, hydrogen chloride, neskondensirovannyh pair of 1,2-dichloroethane and light chlorohydrocarbons of gazorazdelitel arrive in the lower part of the titanium column length of 8 m and an inner diameter of 1400 mm, containing 6 plates, which are irrigated with a speed of 6-8 m2/h of aqueous 5 wt.% ferric chloride solution (II). At 60aboutSince the column is absorbed hydrogen chloride, and chlorine and oxygen is almost completely consumed in the process of redox reactions with ferric chloride (II), 1,2-dichloroethane and hydrogen chloride from the top of AB is 2-dichloroethane through patristical drained by gravity into the container, and a pair of 1,2-dichloroethane and hydrogen chloride arrive in igurative refrigerators, refrigerated brine with a temperature of -35aboutWith, for comensoli 1,2-dichloroethane. Exhaust gases from gazorazdelitel with temperature (0 to minus 20aboutWith come in refrigerators-absorbers, in which hydrogen chloride is absorbed by the circulating water.

The resulting water of 0.5-1.5 wt.% the hydrochloric acid solution is circulated in a closed cycle to the content of HCl in a solution of 3.0-10.0 wt.% and then fed into the vessel containing the carbonate iron (II), formed by the dissolution of carbonate of iron chloride solution iron (II) with a concentration of 1.0-5.0 wt.% postupy speeds of 6-8 m3/h for irrigation titanium absorption columns.

The content of 1,2-dichloroethane, 1,1,2-trichloroethane and other choreodrama hydrocarbons in 1,2-dichloroethane raw in the exhaust gases were estimated chromatographic according to GOST 1942-86 section 4.

The oxygen content in the exhaust gases after absorption with an aqueous solution of iron chloride (II) was evaluated using coloradamar.

The content of ethylene, chlorine in the exhaust gases at the inlet and outlet of the absorption column were evaluated by chromatographic (ethylene) and iodometric titration (chlorine).

P R I m e R s 2-5 (izopet,2-dichloroethane raw and gases are summarized in table.

P R I m e R s 6-10 (control). Synthesis of 1,2-dichloroethane carried out as in example 1. Download components, conditions of formation and properties of 1,2-dichloroethane raw and gases are summarized in table.

As can be seen from the data summarized in the table, the process for producing 1,2-dichloroethane at a molar ratio of ethylene : chlorine in smaller proportions than claimed, leads to a significant content of molecular chlorine in the exhaust gases, which dramatically increases the amount of iron chloride (II) required for complete binding of chlorine.

The process for producing 1,2-dichloroethane at the ratios of ethylene, chlorine, larger than claimed, leads to a significant waste of ethylene, utilization of gases associated with significant energy costs condensation or sigana gases. It also increases pozarovzryvobezopasnost process for producing 1,2-dichloroethane due to the presence in the exhaust gases of the significant content of ethylene.

When carrying out process for producing 1,2-dichloroethane at temperatures lower than the boiling point of 1,2-dichloroethane, dramatically decreases the performance of charator.

The temperature of the synthesis and the pressure in chloretone due to the fact, when using aqueous solutions of ferric chloride (II) with a concentration of less than 1.0 wt.%, not achieved full binding molecular chlorine and capture the necessary oxygen, which reduces the efficiency of cleaning gases (see example 8).

The use of more concentrated solutions of iron chloride (II) than claimed, was not feasible due to hydrolysis of ferric chloride (III), and selection process of absorption of insoluble oxychloride iron.

Carrying out the absorption of gases at temperatures less than 40about(See example 10) does not ensure the full removal of the gases of chlorine and oxygen due to the low rate of oxidation of iron chloride (II).

Carrying out the absorption of gases by iron chloride (II) at temperatures exceeding 80aboutSince it is impractical because of the emergence of a significant amount of insoluble oxychlorides and oxides of iron (III), which complicates the process.

Thus, the proposed method for producing 1,2-dichloroethane in comparison with the prototype has the following advantages:

allows you to improve the quality of 1,2-dichloroethane raw at the expense of education in the process of reaction of 1,1,2-trichloroethane;

reduces consumption rates of ethylene in obtaining 1,2-dichloroethane;

reduces pozarovzryvobezopasnost processed economy of the process.

Conditions for producing 1,2-dichloroethane, its properties and the properties of gases shown in the table.

METHOD for producing 1,2-DICHLOROETHANE by reacting ethylene with chlorine in the presence of oxygen and a catalyst - iron trichloride in liquid 1,2-dichloroethane at elevated temperature and pressure, the allocation of 1,2-dichloroethane condensation, purification of gases and 1,2-dichloroethane raw and subsequent rectification 1,2-dichloroethane, characterized in that the goal of improving the quality of 1,2-dichloroethane and reduce pozarovzryvobezopasnost process, the process is carried out at a molar ratio of ethylene : chlorine 0,995 - 1,005 : 1.0 at a feed rate of the chlorine into the reactor containing 5 - 10% vol. oxygen, 300 - 900 m3/h at a feed rate of ethylene 268 - 860 m3/h in the presence of 0.005 - 0.5 wt. % iron chloride (III) with 84 - 102oWith and (1,0 - 1,8) 105PA and the exhaust gases from the stage of selection of 1,2-dichloroethane condensation miss at 40 - 80oWith water through 1 - 5% solution of iron chloride (II).

 

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