SU559639A3 - The method of producing tetrachlorethylene - Google Patents

Description

The graphite layer should have a good transmissivity for gas with a large specific surface area and relatively high and uniformly distributed electrical conductivity of HOMIIMO with good thermal conductivity. These properties of grafgst; they are achieved, for example, by the fact that the individual particles of spherical 1№1, or also by the fact that they have the form of salting, obtained using sieves n correspond, for example, to the size of the hole of the sieve 5-10, 10-15,15- 25 mm.

The material of the core layer and electrodes consists of pure yush of almost pure carbon, similar in composition to graphite. The compounds of impurity elements (eg, zinc, iron, magnesium, aluminum, silicon) or 6 first metals must not be contained in it or are contained only in nothing Kojm4ecTBax. In addition, the material must have a certain mechanical strength.

An essential feature of a suitable coal is that, in addition to 1shz specific resistivity, e.g. 10-100 ohm-mm / m, it has a high thermal conduction, preferably 10-100 kcal / mh.

Corresponding graphite or artificial coal, respectively, is obtained, for example, from low-ash cokes when coking binders are used while heating without access to air at 2,500–3,000 ° C.

The heating of the reactor is mainly carried out by single- or three-phase alternating current, and according to the size and design of the reactor, electrodes are created on the order of only 10-10000 volts. Temperature control is carried out, for example, using a combination of adjustable transformers and 1 high current transformers.

The electrodes and the naspga layer can be disposed with respect to each other, for example, as follows. When using single-phase alternating current, the layer is in a cylindrical vessel in which the electrodes are immersed above and below, or one wall of the vessel is one electrode, and the diitral graphite rod is the other.

In the case of large-capacity installations, the operation of the reactors is most expediently carried out using three-phase current. For this purpose, parallel to the system of three separate single-phase reactor sludge types operate the nodes of the three electrodes immersed in the layer directly by three-phase alternating current.

The reaction mode can be carried out, for example, as follows. Carbon tetrachloride is introduced in the gaseous state into the pyrolysis 1P 1Y reactor, i.e. in front of the entrance 6, the near-node site is heated to 77-7 50 ° C. At the same time, pyrolysis is already beginning to a small extent according to temperature.

Technically suitable reaction speed and selectivity are obtained if the reaction is carried out at 750-950 ° C, preferably §00-900 ° C.

Pure carbon tetrachloride does not need to be introduced into the reactor. It may contain other

hydrocarbons, such as hexachloroethane south hexachlorobenzene.

Gases such as hydrogen chloride, chlorine or inert gases such as hydrogen chloride can be passed through the pyrolysis reactor with chlorohydrocarbons.

nitrogen or noble gases without significantly reducing reactor power and reaction selectivity. Dilution with hydrogen chloride and inert gases even increases the selectivity of the reaction and the degree of conversion.

by reducing the partial pressure of chlorine. The pressure during pyrolysis is 1-3 atm ..:

In order to avoid the formation of equal quantities of hexachloroethane due to the reaction of carbon tetrachloride with chlorine and thereby to reduce the selectivity of the reaction, it is necessary to sharply lower the temperature of the reaction mixture directly behind the pyrolysis reactor and, in addition, to separate chlorine from tetrachloroethylene. it

This is achieved, for example, by introducing a hot product into a quench column, where due to its mixing with liquid carbon tetrachloride or liquid reaction products, the temperature of the reaction mixture drops sharply.

below 100 ° C. From this column, chlorine is taken from the top, and from the bottom of the tetra column is orethylene, unreacted carbon tetrachloride and side. Further processing of reactive 1-WHITE products is carried out, for example, with

POM01TSI series of consecutive columns.

At a reaction temperature of 1 to 50 kg of carbon tetrachloride per liter of reaction space per hour, for example, 1,000-10,000 g / l-h are obtained.

tetrachlorethylene and at the same time an equivalent amount of chlorine.

The degree of conversion is, for example, 40-80%, and the selectivity is 90%, if hexachloroethane is considered a byproduct, or more

97% if it is circulated by the product which, when recycled to the reactor, is converted to tetrachloro and chlorine.

In the number of by-products, in addition to hexachloroethane, small amounts of hexachlorobenzene and hexachlorobutadiene are obtained, respectively. Under optimal reaction conditions, however, they constitute less than 1% of the reacted material. Soot formation is not observed; shsh is observed only in so little

That achieves a continuous operation time of more than 1000 working hours. Corrosion of graphite material is negligible or excluded.

The resulting tetrachlorethylene after dnstil dai has a high degree of purity; so by

free of trichlorethylene, which is contained in

as an undesirable impurity in products obtained by other methods.

Chlorine MOZH150 to obtain in liquid and gaseous form and disposed of in other methods of chlorination.

Example 1. In the middle part of a vertically arranged quartz tube with an inner diameter of 40 mm and a length of 400 mm, there is a layer of artificial carbon grains with a size of 5-10 mm along the length of 250 mm. Grains are obtained by mechanical breaking of commercial, dense, highly graphitized low-ash artificial coal, which has an electrical resistivity of approximately 10-30 ohm-mm / m. The thermal conductivity of this artificial carbon is 50-100 kcal / m "h degree. The volume of the graphite layer, i.e. the reaction space is about 315 ml. The upper and lower ends of the quartz tube serve to guide two graphite electrodes that are immersed in the layer. Their diameter is about 35 mm, and the diameter in the depth of immersion is about 15-30 mm. The space between the electrodes and the wall of the quartz tube is hermetically sealed with a mixture of asbestos liquid glass.

Through a high current transformer and water cooled pole shoes in the electrodes, a voltage of 10–20 V is applied. The current is controlled by means of a pre-connected adjustable transformer, the initial voltage of which is about 220 volts.

The temperature control in the layer is carried out using a thermocouple introduced into the layer through the upper drilled electrode and the quartz core.

The casing layer and electrodes consist of the same graphite material. At the upper and lower ends of the reaction space, two displaced, 180 ° fittings were soldered on a quartz tube. The Lower Fitting is the reactor inlet, and the upper outlet. To protect against radiation. the entire reactor is thermally insulated with a layer 5 cm thick of quartz felt and a successive layer of fireclay bricks.

2310 g / h are introduced into this reactor at ibO ° C and a pressure of 1 atm. gaseous preheated carbon tetrachloride. This corresponds to a flow rate of 7.34 kg of CCI4 per 1 liter of reaction space per hour.

Reaction products with a temperature of about

850 ° C in a quench column directly connected to the reactor by quenching with liquid carbon tetrachloride or a liquid reaction product is quenched to temperatures below 100 ° C. In this column, the chlorine from the remaining reactive products is rapidly separated.

From the top of the column, a mixture of 710 chlorine and 40 g of ecu is extracted per hour, and from the bottom of the column per hour about

1553 g of a liquid mixture of chlorohydrocarbons of the following composition (in g):

Tetrachlorethylene814

Tetrachloride carbon 700

Hexachloroethane34

Hexachlorobutadiene4

Hexachlorobenzene1

The composition is determined by GLC analysis and by fractional distillation. In products and on the bulk layer in the reactor after operation for 1000 hours, no soot deposits are detected. The degree of carbon tetrachloride is 68%. The selectivity of tetrachlorostilen formation is 96%; its output is 2580.

The electrical energy consumption is 40-45 kWh. per 100 kg of tetrachlorethylene.

Example 2. The production of OPG is varied in such a way that, instead of carbon tetrachloride, a gaseous mixture of 2100 g of carbon tetrachloride and 210 g of hexachloroethane is introduced into the reactor.

At the same time, approximately 680 g of xeofs and 30 g of GCU are taken from the top of the quench column every hour, and from the bottom - 1595 g of the liquid mixture about the composition (in g):

Tetrachlorethylene 8I)

Carbon tetrachloride TOT5

Tetrachloroethane35

Hexachlorbate: adaen4

Hexachlorobenzene1

As in Example 1, no soot release is observed.

In the calculation of tetrachlorethylene, the output is 27 (., And the consumption of electrical energy 40. By. 100 kg of tetrachlorethylene.

Example 3. The nsh5ta mode is according to timer 1, so varied that, instead of carbon tetrachloride, a gaseous mixture of 1540 g of carbon tetrachloride and 112 n (in terms of 0 ° С and 760 mm Hg) is injected into the reactor. .) hydrogen chloride with a temperature of about 300 ° C.

In the processing unit receive per hour (in g): Chlorine535

Hydrogen chloride112 nl

Tetrachlorethylene620

Carbon tetrachloride

Hexachloroethane14

. Hexachlorobutadiene 1

Hexachlorobenzene 0.7

Moreover, the degree of conversion of the CCU is 76%; tetrachlorethylene formation selectivity of 98%; its output is 1970 g / lch.

Claims (2)

Example 4. The experiment according to example 1 is varied so that instead of carbon tetrachloride to a temperature of about 850 ° C, a preheated mixture of 1540 g of carbon tetrachloride, 56 nl of hydrogen chloride and 56 nl of chlorine is introduced into the reactor at 300 ° C. In the processing unit, per hour (in g); Chlorine Hls, hydrogen is obtained. Tetrachlorethylene. Carbon tetrachloride. Hexachloroethane. Hexachlorobutadiene. Hexachlorobenzene. This results in a CCI4 conversion degree of tetrachlorethylene formation 93% and a yield of 1415 g / l-h. Example 5. Experience according to an example varies t-akim Thus, the p-o pressure is higher from 1 to 2 atm, and the SST flow rate is from 2310 to 5000 g / h. At the processing unit, the following is produced per hour (in g): Chlorine 921 Tetrachlorethylene, 985 Carbon tetrachloride 2850 Hexachloroethane. 24Q Hexachlorobutadiene 2 Hexachlorobenzene1 turning sss 43% selectivity of tetrachlorethipene formation 85% (Hexachloroethane as a side product) 1 and 99.7% Cge chloroethane as a circulating product). Exit of ärchlorethylene 3120 g / l.h. Example 6. The experiment according to the example is varied in such a way that the temperature in the reactor is increased from 860 to 930 C. In the processing unit, the radiation is per hour (in g): Chlorine 780 Tetrachlorethylene 872 Carbon tetrachloride 600 Hexachloroethane 44 Hexachlorobutadiene 8 Hexachlorobenzene5 In this case, the degree of conversion of CCU is 74% tetrachlorethylene formation selectivity 95% yield 2,770 g / l-h. Example 7. The experiment according to the example is varied in such a way that the temperature in the reactor is reduced from 860 to 760 ° C. 8 processing facilities are obtained per hour (in g): Chlorine 556 Tetrachlorethylene Carbon tetrachloride Hexachloroethane Hexachlorbutadiene Hexachlorobeneol Walls and reactor gas outlet are free of -or sediments. CCi4 conversion rate 55%; tetrachlorostilen formation selectivity 91%; its yield is 1980 g / lh. Claim 1. The method of obtaining tetrachlorethylene of the paths of pyrolysis of carbon tetrachloride over electrically heated solid carbon-containing contact at elevated temperature followed by cooling of the reaction mass, characterized in that, in order to increase the selectivity of the process, the process is subjected to pyrolysis of hydrogen chloride or to the mixture, and to the freezing rate. -3 atm., And graphitized carbon is used as a solid carbon-containing contact. 2. A method according to claim 1, characterized in that the process is carried out at 800-900 ° C. 3. The method according to w. 1 and 2, characterized in that the pyrolysis is carried out in the presence of chlorine and / or hydrogen chloride. 4. Method 1sh. 1-3, characterized in that graphitized carbon is used with a specific electrical resistance of 10-100 ohm-mm / M and a thermal conductivity of 10-100 kcal / mh degree. C. 5. A method according to mb, 1-4, about t l-and that with the use of graphitized carbon having the form of spherical particles. Sources of information taken into account in the examination: 1. Methods of Organizational Chemistry. Ed. A.N. Nesme. M., 1973, p. 264. 2. Pateit CIUAN 1930350, 260-166.04.12.31