JPS60325B2 - Production method of 1,1,1-trichloroethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 111,1-trichloroethane.

Hydrochlorination of ethylene in the presence of a Friedel-Klaff metal halide catalyst
bn) is an old well-known operation.

This technology is used in an ebullated bed reactor
tor) using primarily ethylene and substantially pure hydrogen chloride. The composition of the ebullated bed is essentially the product of hydrochlorination. A number of Friedel-Kraf metal halide catalysts have been suggested and a full range of them have been used depending on the conversion, reaction temperature, pressure, etc. but,
Aluminum chloride or ferric chloride are the preferred and most commonly cited metal halide Friedel-Cluff catalysts. The main product of this reaction with ethylene is ethyl chloride. It has become common practice to purify the ethyl chloride from this reaction before use to produce any of the more highly chlorinated materials. Similarly, hot salification of ethyl chloride is a well known process. temperature, pressure,
The product obtained is determined by the ratio of chlorine and the presence or absence of a catalyst. For example, chlorinating ethyl chloride to 1,1-dichloroethane, recycling this 1,1-dichloroethane with the ethyl chloride feedstock, and
Many methods are known for combining di- and trichloro-products, such as preparing 111-trichloroethane therefrom. Several techniques have been disclosed for implementing such methods. Again in each of these processes, it is common to separate the effluent product of chlorination into the desired product and recycle liquid streams. Some of the desired product may be recycled as a temperature control and thus chlorination control medium. Hydrochlorination of unsaturated partially chlorinated hydrocarbons such as vinyl chloride, vinylideso chloride, cis- and trans-dichloroethylene
Documents in the prior art are provided for each. The use of ferric chloride and/or aluminum chloride as metal halide Friedel-Crafts catalysts for these hydrochlorinations is also well known. 1 of unsaturated partially chlorinated hydrocarbons
The separation of each of the species or products of hydrochlorination is a somewhat tedious operation requiring several distillations in order to obtain a product of high purity. It is clear from the prior art that skilled artisans are willing to proceed with the production of polychlorinated ethylene and ethane in a stepwise manner, separating the intermediate products and purifying them before using them in the next step. be. This operation requires several large purification systems in between the various steps and results in compounds that are now present as impurities in the desired product, and which cannot be removed unless removed by chemical means. This will cause problems in the next process. Therefore, ethylene and chlorine are the two external reactants introduced during the process, and then 1.1
It would be advantageous to provide a process that yields 11-trichloroethane and minimizes intermediate separation of reaction products to provide feedstock for each step of a multi-step process.

According to the invention, with particular attention to the drawings, FIG. 1, ethylene is mixed with hydrogen chloride 15 and fed to hydrochlorinator A, where the ethylene is hydrochlorinated to ethyl chloride 3.

The reaction is carried out in an ebullated bed of aluminum chloride in which the aluminum chloride catalyst is decomposed. The gaseous product of this first hydrochlorination (ethyl chloride) then obtained
The stream is combined with recycle fraction 20 and chlorine and heated to thermal chlorinator B.
Heat chlorination inside. Two recycle fractions obtained from product separation in the latter step have boiling points between about 370 and about 60 CC and are primarily 1,1-dichloroethane. This thermal chlorination is carried out between about 400° and 550°. The resulting product stream 5 of this hot salinization is subjected to liquid cooling, in which chlorinated hydrocarbons such as those having a boiling point above about 40 qo are converted from gaseous to liquid state. Non-liquefied gases 6, mainly hydrogen chloride, vinyl chloride and vinylidene chloride, and unreacted ethylene are taken overhead.Liquid 7 resulting from cooling C of the product effluent from the thermal chlorinator is partly taken as cooling liquid. The vinyl chloride, vinyl chloride and hydrogen chloride from this cooling are mostly mixed with the unreacted ethylene overhead fraction and the resulting mixture 10 is introduced into a liquid hydrochlorinator (ferric chloride is a metal halide-free Dell-Cluff catalyst). Thus, effectively the entire effluent from the hot salinizer is cooled and sent directly to the ferric chloride hydrochlorination reactor D. This operation: There is no need for distillation between steps in the process: however, the 1,2-dichloroethane formed during this reaction and present together with the product 1,1,1-trichloroethane must be removed, so that the final product This purification may consist of a distillation of the product stream 11 from the hydrochlorinator D. As illustrated, the first distillation B increases the stringency of the lights fraction (lights fraction). ) 14, mainly hydrogen chloride and 4 parts of ethylene, vinyl chloride, ethyl chloride, and pinylidene chloride are separated.The undistilled part (bottoms) from distillation B is further distilled in F. to separate 1,1-dichloroethane and cis- and trans-112-dichloroethylene stream 17. The bottoms from distiller F is further distilled to GI.1.
1-trichloroethane 18 and a bottom fraction of high-boiling components, mostly ethylene dichloride, trichloroethylene, 1,1,2-trichloroethane and asymmetric tetrachloroethane are obtained. The cis- and trans-dichloroethylene produced in small amounts in the hot saltifier have boiling points such that it is practically impossible to separate the cis isomer from the recycled 1,1-dichloroethane by distillation.

If both isomers or the cis isomer alone are left with recycled 1,1-dichloroethane, they pass essentially unaffected through the thermal chlorinator and hydrochlorinator, thereby being recycled. Continuously increase the concentration in circulating 1,1-dichloroethane. Recirculation of cis- and trans-dichloroethylene before use in the chlorinator 1.1
Maintaining it at a relatively low level by removing it from the dichloroethane stream 20 improves the efficiency of thermal chlorinators and ferric chloride hydrochlorinators.

Two operations are provided for this removal; one separates the trans isomer by distillation and partially isomerizes the cis isomer at the hot chlorination temperature to approximately 60% cis and 40% % trans. The trans isomer can then be removed by distillation and the remaining cis isomer sent to a thermal chlorinator where partial isomerization is repeated. Another operation is to cold chlorinate the recycle stream while returning it to the hot saltizer to convert cis- and trans-dichloroethylene to high boiling compounds. Recycle fraction 14 consists of ethylene that has not reacted or has formed in the hot salinizer, hydrogen chloride that has not reacted in the hydrochlorinator, ethyl chloride and small amounts of vinyl chloride and vinylidene chloride. These components are returned to the process and are approximately 1/2 of the liquid stream 14 represented by liquid stream 15.
provides hydrogen chloride for the hydrochlorination of ethylene in hydrochlorinator A. Excess hydrogen chloride 16 is removed from the process. In another operation according to the invention (see dotted line in FIG. 1), liquid 7 resulting from the cooling of the product stream from thermal chlorinator B is used partly as cooling liquid and mostly as a Friedel-Cluff catalyst. , particularly ferric chloride, and more particularly to an ebullated bed dehydrochlorinator containing about 100 pm of ferric chloride.

The dehydrochlorination reactor was operated primarily under conditions to dehydrochlorinate 1,1,1-trichloroethane to vinylidene chloride, thus removing 1,2
-Allows the separation of dichloroethane. The gaseous products 8 (boiling below about 60 qo) obtained from the intraday dehydrochlorination are combined with vinyl chloride, vinylidene chloride and hydrogen chloride from cooling tower C and unreacted ethylene overhead fraction stream 6. The resulting mixture 1 river is mixed,
The ferric chloride is introduced into liquid hydrochlorinator D, which is a metal halide-free DeCluff catalyst. The high boilers from the day are sent to distiller 1 to recover recyclable chloride, primarily 1,1-dichloroetaso 12, which is mixed with recyclables from product finishing system 17. Ru. The remainder of this high boiler may be removed from the process and combined with the heavy fractions (heavEs) from the 13,1.1.1-trichloroethane product, and these heavy fractions can be separated or suitably treated. is decomposed into usable higher polychlorinated hydrocarbons. , Therefore, as suggested in the discussion above, the removal of 1,2-dichloroethane from the process after its formation in thermal chlorinator B will result in the desired product, 1,1,1-trichloroethane. Substantially reduces the stringency of the purification process to obtain tan in high purity.

According to the present invention, approximately 4.4 pounds (2.0 kg) of the approximately 33.9 pounds (15.4 k9) of ethylene can be separated as product of the total process) and approximately 7
4.6 pounds (33.0 kg) of hydrogen chloride was added to about 50 kg of hydrogen chloride in the presence of an aluminum chloride catalyst in ebullated bed hydrochlorinator A.
0 qo and about 35 psig (2.47 k9/ground) to yield about 74.9 pounds (34.0 k9) of ethyl chloride and about 30.4 pounds (13.8 k9) of excess hydrogen chloride.

About 21.8% of this was obtained as the product of the total reaction.
Mix with 9.9k9 pounds of ethyl chloride and about 98.9 pounds of 1,1-dichloroethane. This mixture was combined with 153.7 pounds (69.8k9) of chlorine in thermal chlorination reaction zone B at 47.5°C and 4 seconds.
React for about 2 seconds on bamboo grass (2.82k9/ground).
The resulting product stream was adjusted to 45 q○ and 35 psig.
Ferric chloride (50 k9/kg) is fed into a liquid bed hydrochlorination reactor operated at
．． 1 in 2 pounds (22.8k9) perchloroethylene
0.4 pounds (4.72k9)) to obtain - in pounds (k9): 134.9 (61.0
) HC1 (hydrogen chloride) 4.39 (1.
98) C2 day 4 (ethylene) 0.74
(0.34) C2day3CI (vinyl chloride)
21.77 (9.85) C2 days 5CI (ethyl chloride) 0.95 (0.43) 1.1-C2 days 2CI
2 (pinylidene chloride) 2.21 (1.00) t-C2 day 2CI2 (trans-1,2 dichloroethylene) 102
．． 09 (46.6) 1,1-C2day4Ci2(1,1-dichloroethane)5
．． 27 (2.39) C-C2 ratio CI2 (cis-1・2-
dichloroethylene) 106.49 (48.2) 1-1-
1-C2 day 3CI3 (1.1.1-trichloro kotan)
1.57 (0.71) C2HC13 (.1, 1, 2-trichlorethylene) 1
．． Muscle (0.76) 1.2-C2 day 4CI2 (1,2-dichloroethane) 4.50 (2.04) 1,1,2-C2
Day 3CI3 (1,1,2-trichloroethane) 1.25
(0.57) 1.1.1.2-C2 day 2C1
This product stream is separated in several stills (E, F and G) to obtain the product (1,1,1-trichloroethane), a recycle stream and a heavy fraction, of which The latter is removed from the system.

Hydrogen chloride, vinyl chloride, ethyl chloride, and vinylidene chloride and unreacted ethylene are separated as overhead on the first still and sent to aluminum chloride hydrochlorinator A; 1.1 from the second still -C2 days 2C
I2, cis-1.2-C2day2CI2 and trans-
The overhead of 1.21C2 days and 2CI2 is sent to hot salt conversion reactor B, which is chlorinated (taking care to exclude light or other irradiation) at 25°C during the process to react cis- and trans-dichloroethylene. This creates a heavy fraction and prevents it from accumulating in the reactor. 1・111-
Trichloroethane is the product from the third still G and the bottoms from the third still is the heavy fraction.

Furthermore, to illustrate the use of the present invention in a multiple reaction train for the production of 111,1-trichloroethane from only ethylene and chlorine as combined feedstocks as set forth in the drawing (FIG. 1): Approximately 183.9 pounds mole/
day (83.0k9-mol) of 1.1.1-trichloroethane, about I. 5 lb-mol/day (15.6 k9-mol) of heavy components (1,2-dichloroethane, cis- and trans-1,2-dichloroethylene, trichlorethylene, 1,1,2-trichloroethane and unsymmetrical tetrachloroethane) about 231.7 pounds-moles/day (105 k9-moles) of ethylene and about 49
Total feedstock of 9.2 lb-mol/day (83.0 k9-mol) of chlorine.

These latter compounds, heavy components, are removed from the process along with hydrogen chloride. To illustrate the use of the dehydrochlorination step (dashed line in Figure 1), a liquid such as that obtained from cooling of a thermal chlorinator effluent (stream 7 in Figure 1) and anhydrous ferric chloride were Feed into a 1000 cc vessel equipped with a submerged distillation column.

The effluent rate from the top of the column is adjusted so that the overhead temperature is maintained at about 40°C. reboiler
The temperature of the material remaining inside ranges between 62 and 78 pm. After 7 hours, close the feed pump and allow the system to cool.
During a period of 7 hours, 418 mol of liquid and 0.5 mol of FeC1
3 was supplied.

The table below shows the amounts of various compounds fed and recovered. From the above, it is clear that 1.1.1 tritric 00 ethane is converted to vinylidene chloride in high yields, thus facilitating its separation from the compounds incorporated in the thermal chlorinator reaction product. be.

The embodiments of the present invention are as follows.

'1} Method described in the claims.

■ [c} Most of the liquid product produced in (2) is dehydrochlorinated, thus converting most of the 1,1,1-trichloroethane to vinylidene chloride, and the product from dehydrochlorination The method described in {1-- above}, which comprises recovering 1,1-dichloroethane by distilling the residue of the product.

'3' {The second product mixture formed in the skin is distilled to remove the trans-1,2-dichloroethylene and the remaining portion is returned to the hot saltwater zone where the trans-1,2-dichloroethylene is removed.
Approximately 60% by partially isomerizing 2-dichloroethylene
A mixture of cis-1,2-dichloroethylene and 40% trans-1,2-dichloroethylene is produced, and the trans-1,2-dichloroethylene is removed by distillation. The method described in {1-- above, which comprises returning to the thermal chlorination zone.

■ The second product mixture formed in {d is exposed to light,
converting cis- and trans-1,2-dichloroethylene to trichloro- and tetrachloroethane by chlorination in the absence of a catalyst and returning the product mixture thus formed to the hot chlorination zone. The method described in {1} above.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet illustrating the method of the invention. A is a hydrochlorinator, B is a thermal chlorinator, C is a cooler, D
is a ferric chloride hydrochlorinator, E, F and G are a distiller, day is a dehydrochlorinator, 1 is a distiller, 1 is ethylene, 15 is hydrogen chloride, 3 is ethyl chloride, 17 is 1・1
-dichloroethane and cis- and trans-dichloroethane
2-dichloroethylene, 18 is 1.1.1-trichloroethane. Shiota Z

Claims (1)

[Claims] 1 (a) Produce ethyl chloride by reacting ethylene with hydrogen chloride (which hydrogen chloride is obtained from another step of the process) in the presence of an aluminum chloride catalyst:
(b) reacting the ethyl chloride, recycled ethyl chloride and 1,1-dichloroethane with chlorine at a temperature of 400-550°C; (c) subjecting the reaction mixture from (b) to liquid cooling, thus producing (1) the chloride; producing a gaseous product mixture consisting of hydrogen, vinyl chloride, and vinylidene chloride, and (2) a liquid product; (d) returning a small portion of the liquid product to the cooling zone; part (c) with the gaseous product mixture produced in (1) and hydrochlorinating this latter mixture to hydrogen chloride,
Ethylene, ethyl chloride, vinyl chloride, vinylidene chloride,
1,1-dichloroethane, cis- and trans-1,
2-dichloroethylene, 1,1,1-trichloroethane, ethylene dichloride, trichloroethylene, 1,1,2-
producing a second product mixture consisting of trichloroethane and unsymmetrical tetrachloroethane; (e) separating hydrogen chloride, ethylene, ethyl chloride, vinyl chloride and vinylidene chloride from the second product mixture; (f) separating the second product mixture; 1,1-dichloroethane and cis- and trans-1,2-dichloroethylene are separated from the remaining part of the product mixture in (g) 1,1,1-trichloroethane from the part remaining after separation in (f). A method for producing 1,1,1-trichloroethane, which comprises separating 1,1,1-trichloroethane.