DE1568582B - Process for the production of dichloroethane and trichloroethane - Google Patents

Description

Dichloroethane and trichloroethane are valuable Products; they are especially used as precursors for the production of trichlorethylene and perchlorethylene used by oxychlorination. The di- and trichloroethanes were previously mostly in liquid Phase proceeding reactions produced, whereby a reaction mixture is obtained, which for recovery the desired products must be distilled. Such reaction mixtures often contain By-products that boil at low temperature and must be removed before the reaction product is used as a precursor for a trichlorethylene or Perchlorethylene process can be used.

There was therefore a need for a fast and efficient process for the production of Dichloroethane and trichloroethane from ethylene, by a process in which essentially all of the supplied ethylene and chlorine are utilized, a reaction mixture being obtained that a large amount of the desired products as well as by-products only at high Temperatures containing boiling chlorinated compounds, which neither with the normal use of Dichloroethane and trichloroethane still in oxychlorination reactions, which dichloroethane and trichloroethane are supplied to exert an adverse influence.

The present invention relates to a process for the production of dichloroethane and trichloroethane, that consists in adding chlorine and ethylene each in vapor form in a molar ratio of chlorine Ethylene from 1.1 to 2: 1 at 80 to 350 ° C at least In a catalyst bed of sodium chloride, potassium chloride, or mixtures thereof for 0.1 second with a particle size of 8 to 0.15 mm and the gaseous reaction products, which contain dichloroethane and trichloroethane, either wins as such or in the usual way separates.

In a particularly advantageous embodiment, the chloro-ethylene ratio is 1.2 to 1.6: 1, the temperature of 200 to 220 ⁰ C and the particle size of the components of the catalyst bed 4.0 to 1.2 mm. It is particularly advantageous to use the catalyst bed in the form of a fixed bed.

Preferably the reaction is carried out in the presence of an inert diluent gas or vapor, for example Hydrogen chloride, nitrogen, carbon tetrachloride, perchlorethylene, or another gas or Steam, which is inert to the reaction, carried out. If an inert gas is used, then it is used in an amount up to approximately 50 percent by weight, based on the total weight of the reaction gases, used.

It has surprisingly been found that in the method according to the invention, the process is carried out in the presence of the aforementioned catalysts practically complete utilization of the chlorine and ethylene takes place, with one product is obtained that has essentially no low-boiling by-products such as vinyl chloride and vinylidene chloride, which is often used in other reaction processes between chlorine and Incurred ethylene. In addition, it is excellent through the properties made possible by the catalyst Reaction control avoids the development of hot spots which lead to an over-oxidation of the ethylene to lead.

The implementation sometimes involves small amounts, in the order of 5 to 15%) formed on high-boiling compounds such as tetrachloroethane and pentachloroethane. this however, is not a disadvantage, especially if the reaction product is used as a feed for a Oxychlorination reaction for the production of perchlorethylene and trichlorethylene is used because these high-boiling compounds during the oxy-chlorination reaction to give products are cracked, which are suitable as precursors for the desired compounds perchlorethylene and trichlorethylene. These results won't using beds of other solids, e.g. silicon carbide, porcelain packing or glass spheres. Are these other materials used (see those below Comparative examples), then either the starting materials do not react completely or violent ones occur and uncontrollable reactions.

Particles with a "diameter of less than 0.15 mm tend to be blown out of the reactor, whereas particles with a diameter of more than 8 mm are difficult to produce and in any case have a small surface area compared to the particles used according to the invention, which is suitable for contact with the reaction gases is available.
A particularly suitable material for the catalyst bed is rock salt (a form of this can be obtained as the naturally occurring mineral halite), which is available in any desired particle size; Pure rock salt is particularly suitable. Another suitable material is sylvinite, a naturally occurring mineral composed of approximately 50 parts sodium chloride and 50 parts potassium chloride on a mole basis. This ratio of sodium chloride and potassium chloride in the sylvinite is variable and depends on the location of the material; Sylvinite can contain up to 60% either sodium or potassium chloride. Another naturally occurring material useful in the method of the invention is sylvine, a mineral composed primarily of potassium chloride. Amounts up to about 50 percent, based on total weight of solids, that are inert or catalytic to the reaction can be present in the bed provided that they do not accelerate the reaction too much, if catalytic, nor an uneconomically large bed make necessary if they are inert. According to the invention, the use of beds is preferred which are composed essentially of the specified chlorides.

The bed is laid to a depth which has the required residence time of at least 0.1 second and preferably allowed no more than about 10 seconds. The upper limit of the contact time is only determined for economic reasons; it is possible to use the gaseous starting materials and also to leave the reaction products in contact with the bed for an extended period of time. It is only required that the contact persists for a sufficient period of time to allow full implementation. Preferably the bed has a depth of 13 to 127 cm. The bed is preferably a fixed bed of catalyst and diluent particles; however, it is also possible to use the catalyst and the diluent

3 4

put into a vortex state if both are within the specified range (for example

Components of a suitable fluidizable size, 1.1 moles of chlorine per mole of ethylene), then that exists

namely a diameter of 0.6 to 0.15 mm 90% of the reaction product is dichloroethane. the

own. Separation of these products as well as, if applicable

Any suitable 5 of by-products can be prepared for the catalyst bed using conventional methods

Apparatus are used, it is only required- carried out, for example by vacuum fraction

Lich ensure that the starting materials are chlorinated and preferably by absorption,

and ethylene as well as any gas used The following examples illustrate the invention,

shaped diluents flow through the bed. .

be able. The product gases are collected and used in Example 1

either used as such or optionally for a 25 mm I.D. (Inside diameter) glass tube with

Separation distilled. a 10 mm thermal sleeve was coated with rock salt (halite

The rate of flow of the starting materials through sodium chloride of particle size 4 to the bed is not critical as long as it is packed sufficiently 2.5 mm to a depth of 56 cm. The tube is, with the additional requirement that 15 was heated in an electric furnace to 200 ° C, the depth of the catalyst bed and the particle whereupon a gas flow of 42.5 mmol / minute ethylene, size of the catalyst / diluent is, 60 mmol / minute chlorine and 16 mmol / minute chlorine that a residence time of 0.1 to about 10 seconds hydrogen was introduced into the reactor is guaranteed. Deeper beds permit the effluent gas stream was passed through a number of faster flow rate, while shallower 20 ⁰ C cooled to 78 traps. The contact time beds require a slower flow rate. in the bed was about 3 seconds. The Product In general, the flow rate should not be collected and after 30 minutes should be about 5 to 100 cm ³ / second / cm ² . weighed the operating time. The collected product

The reaction between chlorine and ethylene is composed as follows:

carried out at 80 to 350 ° C, it being preferable 25 _n ,, ^ · ■ ......

. ,,. ..., _ «-, ·» »At, /, ... .. r_ ·. . Product mmol / minute

is to work at around 200-220C. Is working

one below 80 ° C, then a slow, incomplete 1,2-dichloroethane 21.5

constant reaction is the result, whereas 1,1,2-trichloroethane 17.6 is difficult

rig will control reactions that significantly 1,1,2,2-tetrachloroethane 1.45

be carried out above 350 ° C. 30 pentachloroethane 1.23

The starting materials used according to the invention. The chlorine and carbon balances were unsind Chlorine and ethylene. These raw materials are 100%. This means that 98.5% of the intake a molar ratio of 1.1 to 2 moles of chlorine per led ethylene and practically all of the supplied Moles of ethylene and preferably 1.2 to 1.6 moles of chlorine chlorine had been consumed, used per mole of ethylene. If more than approximately 35 ... 2 moles of chlorine are used per mole of ethylene, then the B e 1 s ρ 1 e 1 2 Reaction too violent and difficult to control. The same reactor and the same ones were found bring to. If less than 1.1 moles of chlorine are used per reaction condition as in Example 1, Moles of ethylene used, then the ethylene is used only with the exception that the feed stream is off incompletely consumed. . 4 ° 42.5 mmol / minute ethylene, 52.2 mmol / minute chlorine

Together with the starting materials chlorine and 24 mmol / minute hydrogen chloride existed. the

Ethylene can be used as a diluent gas. Product flow became more sustained after 30 minutes

The diluent gas can be collected and analyzed in amounts up to about operating time; were there

50 percent by weight, based on the total gas, the following results are obtained:

form or vapor feed, used 45 product mmoles / minute will. In the cases in which em low

Chlorine-ethylene ratio within the specified 1,2-dichloroethane 37.7

Area is applied, namely about 1.1 mol 1,1,2-trichloroethane 7.6

Chlorine per mole of ethylene, the diluent is 1,1,2,2-tetrachloroethane 0.31

practically not necessary, since the implementation in not 50 pentachloroethane 0.53

done very violently. If the ratio lies The chlorine and carbon balances were unChlor to ethylene at the upper end of the stated 100%, which suggests that essentially Range, on the order of borrowed all the chlorine and ethylene that has been consumed 1.7 to 2 moles of chlorine per ethylene, then it's purposeful.

moderate to use a thinner to reduce the 5s B e i s ρ i e 1 3 Slow response and get under control

bring. This implementation shows the effect of temperature

Any gas or vapor that opposes the product distribution. It became the same

is inert over the reaction, can be used as a dilution reactor and the same reaction conditions as

medium can be used. To appropriate dilution 60 used in Example 1, with the exception that the

average are hydrogen chloride, nitrogen, perchloric acid reaction temperature was 150 ° C. There were fol-

to include ethylene and carbon tetrachloride. get the following results:

The reaction product contains one in proportion

Equimolar amount of trichloroethane to dichloroethane, product mmol / minute

if the reaction at a molar ratio of chlorine to 65 1,2-dichloroethane 37.7

Ethylene of about 2: 1 is carried out. Becomes 1,1,2-trichloroethane 6.20

less chlorine used, for example in a sym.-l, l, 2,2-tetrachloroethane and penta

Ratio, which at the lower end of the invention chloroethane 0.22

I 568 582

Again, practically 100 per cent of the chlorine and ethylene had been consumed.

Example 4

A 25 mm ID glass tube with a 10 mm thermal sleeve was packed with sylvinite (50 ° / ₀ Silvin, 50 ° / ₀ Halite, diameter 4 to 2.5 mm) to a depth of 56 cm. The tube was heated to 325 ° C in an electric oven. A gas stream of 21.25 mmol / minute ethylene, 30 mmol / minute chlorine and 15 mmol / minute HCl was passed through the reactor with a contact time of 7 seconds. The effluent gas stream was passed through a series of cooled to -78 ⁰ C traps; after 30 minutes the product was collected, weighed and analyzed. The following results were obtained:

Product mmol / minute

Traces of vinyl chloride

1,2-dichloroethane 12.6

1,1,2-trichloroethane 8.4

1,1,2,2-tetrachloroethane 0.25

The chlorine and carbon balances were 100% about, which means about 100 ° / ₀ owned yields.

Example 5

The same reactor and the same reaction conditions were used as used in Example 4, with the exception that the bed is packed with sylvine (KCl 98.5%, NaCl 1.3%, diameter 4 to 2.5 mm) would. The following results were obtained:

Product mmol / minute

1,2-dichloroethane 13.6

1,1,2-trichloroethane 6.8

1,1,2,2-tetrachloroethane 0.8

The carbon balance was about 99.0%, while that of the chlorine was found to be about 99.5% would.

₅ Example A - comparative experiment

This example was done to show the results obtained when other Catalyst beds are used. In this case, calcium chloride with a particle size of 4 ίο up to 2.5 mm instead of the catalyst dilution bed used in Example 4 used under the same conditions as in Example 4. The reaction product thus obtained settled as follows together:

¹⁵ product mmol / minute

Vinyl chloride 6.8

Vinylidene chloride 4.3

cis + trans dichloroethylene 1,4

_{2o traces of} 1,2-dichloroethane

1,1,2-trichloroethane 0.1

Tetrachloroethane 0.5

Unknown high-boiling components 8.15

Charring and coking occurred in the bed. Tar formation took place throughout the system, In addition, polymer formation was observed in the product outlet tube.

Example B - comparative experiment

30 In this example, the effectiveness of the sodium chloride catalyst used in Example 1 with the effectiveness of other typical bed materials. The ones indicated below under a), b) and c) Materials were made under the same

35 conditions as the sodium chloride used in Example 1 was used. The results are below summarized:

catalyst

a) silicon carbide
Particle diameter
4 to 2.5 mm

b) Ceramic fillers
Particle size 4 to 2.5 mm

c) glass balls

Particle size 4 to 2.5 mm

d) halite (sodium chloride)
Particle size 4 to 2.5 mm
(inventive
Catalyst diluent) results

violent, uncontrollable exothermic reaction, excessive charring. No extraction of product possible

mmol / minute

1,2-dichloroethane 23.3

1,1,2-trichloroethane 4.9

trans-l ^ -dichlorethylene 0.1

16.3% of the total product was unknown, 21.5% of the chlorine fed in was unconverted Reclaimed form

Hot spots developed in the bed with a noticeable one at the top of the bed Charring occurred. The carbon footprint was around 80%

mmol / minute

1,2-dichloroethane 19.1

1,1,2-trichloroethane 13.5

1,1,2,2-tetrachloroethane 1.6

Pentachloroethane 2.2

mmol / minute

1,2-dichloroethane 21.5

1,1,2-trichloroethane 17.6

1,1,2,2-tetrachloroethane 1.45

Pentachloroethane 1.23

The chlorine and carbon balances were approximately 100%. This corresponds to a consumption of 98.5% of the ethylene fed and essentially all of the chlorine fed in

Claims (1)

7 8 Claim: ⁰ ^ ^{second lan} § ⁱⁿ a catalyst bed Sodium chloride, potassium chloride or their Mi-process for the production of dichloroethane and mixtures with a particle size of 8 to Trichloroethane, thereby g ekennzeich- 0.15 mm converts and the gaseous reactions e t that chlorine and ethylene are each in 5 products, the dichloroethane and trichloroethane ent vapor form to keep in a molar ratio of chlorine, either as such wins or in excess ethylene separates from 1.1 to 2: 1 at 80 to 350 ° C at least Licher way.