DE1518766C2 - Process for the production of 1,1,1-trichloroethane - Google Patents

Description

1 2

There are several methods of making a bottoms product, which consists essentially of

1,1,1-trichloroethane known, but these have 1,1,2-trichloroethane and a top product

Processes in general have serious disadvantages. (essentially 1.1,1-trichloroethane and 1,1-di-

Such disadvantages include low yields of chloroethane), at least the overhead product

1,1,1-trichloroethane, low conversion of the starting 5 partially condensed in a condenser (G)

substances to 1,1,1-trichloroethane, high catalyst consumption and

need, high carbonization of the reactants, f) the condensate obtained in e) a column III expensive equipment, multi-stage reactors and supplies, from column III pure 1,1,1-trichloro, similar. A problem that often arises is deducted as a swamp product and that is the impurity of 1,1,1-trichloroethane consisting essentially of 1,1-dichloroethane with relatively large amounts of 1,2-dichloroethane, top product at least partially in a condenser Due to the similar volatility, it is very difficult to condense into capacitor (J) , then in a preliminary removal. Another problem that occurs is transferred to the heater (K) and then returned to the contamination of the product with catalyst chlorination stage a), material. Surprisingly, it was found that such impurities should be removed or reduced when driving, because the byproducts of the 1,1,1 -trichloroethane responsible for the process according to the invention are only of low quality. The procedure has also been loaned. . the advantage that it lasts for a long time

In efforts to over-run these difficulties, the necessary winds the industry often does not have the option of shutting down the plant for cleaning Complicated and expensive extraction process to the ab-.

Separation of 1,1,1-Trichioräthans from other halo- The inventive method looks from the Generated hydrocarbon impurities genome introduction of 1,1,1-trichloroethane into the hydromes. Likewise, the prior art often eliminates and thereby avoids chlorinating equipment maize uses expensive equipment, which yields a loss of 1,1,1-trichloroethane from 25 consists of many stages, procedural steps, etc. apparently in the presence of the hydrochlorination catalyst

There is therefore a need for a process that occurs as a result of the formation of 1,1-dichloroethylene,

in which these difficulties are overcome. For a better understanding of the invention

The invention thus relates to a method, the individual steps are based on the method

for the production of 1,1,1-trichloroethane, which is explained in the following drawing,

is characterized by that “ _f

a) Chlorine with 1,1-Di-Mute preheated ^{to 37.8 to 260 0 C a)}

chloroethane in the molar ratio 0.2: 1 to 0.7: 1 in a fluidized bed is chlorine in the chlorination zone via line 1 of fine sand at about 316 together with a preheated 1,1-DichIoräthanbis 427 ⁰ C and a pressure of about 1 to 35 stream 17 initiated. The 1,1-dichloroethane is heated to 15.1 kg / cm ² in a chlorination device (L) to a sufficient temperature so that - if it reacts in a manner known per se, which is essentially reacted with chlorine - a uniform temperature is obtained from 1,1,1-trichloroethane, 1,1-dichloroethane reaction takes place. In other words, heating this preliminary product mixture and hydrogen chloride creates a reaction in which the reaction cools down in a boiler (A) , and is at least partially condensed in a condenser system in such a way that it is thermodynamically in equilibrium (B), that it is unnecessary to add additional heat to the hydrogen chloride in a separator (M) or to separate excess heat from the reaction and remove it to a hydrochlorination zone Temperature from 37.8 to

b) preheat part of the essentially from!, lil-trichloro-45 260 ° C. A more preferred heating ethane and 1,1-dichloroethane existing con temperature is from about 149 to 232 ° C, because below densates of the chlorination stage a) in the above conditions, the by-product formation ver-part a column I is introduced and at the same time is reduced and high yields are achieved. the the processes in stages a) and b) charging of the chlorination zone is set so that

c) Vinyl chloride and hydrogen chloride, which is at least 5 ° that a molar ratio of chlorine to 1,1-dichloroethane partly originates from stage a), is created and kept in the range of 0.2: ter in a hydrochlorination device ( Subject N) to 0.7: 1 and preferably in the range of about hydrochlorination conditions * 0.3: 1 to 0.35: 1. The chlorine: 1,1-dichloroethane

d) the gaseous product mixture obtained in c), ratio that creates a constant reaction temperature consisting essentially of 1,1-dichloroethane, vinyl fenene is said to be closely related to the temperature chloride and hydrogen chloride, brought in one to the 1,1-dichloroethane charge Condenser (C) is at least partially condensed, with the chlorine feed at ambient accruing hydrogen chloride separates and takes place in temperatures. So is the amount of heat that the hydrochlorination device (stage c) leads back through the exothermic substitution chlorination reaction, 60 tion is given off, plus the heat with which the

e) the liquid product mixture obtained in d) is fed into the 1,1-dichloroethane feed, from column I passes, from column I a sufficient amount to create the stabilized reaction within the pro-zone, which consists predominantly of hydrogen chloride. The chlorination reaction in the fluidized duct is distilled off and, if necessary, into the bed is recycled at a uniform temperature in the ge-hydrochlorination device (stage c) 65 entire fluidized bed from about 316 to 427 ° C and preferably and the bottom product, which is essentially wise at a temperature of about 243 to 399 ° C 1,1,1-trichloroethane and 1,1-dichloroethane, stabilized. The reaction is fed in from about the atmosphere of a column II, from column II the pressure up to 15.1 kg / cm ² and preferential

wisely carried out up to 5.92 kg / cm ^2. An excellent working pressure is about 3.81 to 5.22 kg / cm ² with no additional pressure required to transfer the stream back to the hydrochlorator.

Although the chlorination is mostly preferably an adiabatic chlorination, as described above, the process according to the invention can also be carried out under non-adiabatic conditions, d. i.e., heat can be added to or removed from the reaction bed. The fluidized bed in this chlorination zone is composed of fine sand, into which the gases are channeled and converted. To the For best results, the types of sand should be essentially free of nickel and iron and theirs Be connections. The gases are introduced into the bed at such a rate that a good fluidized bed process and equally good heat transfer from the reaction gases to the sand he follows. The only limitation is the speed of the entering gases in that the velocities are compatible with the type of sand used and the type of reactor used must be. It is generally used to create the proper flowability for fine sand it is preferable to keep the superficial velocity of the gases entering the reaction zone at about 0.03 to hold up to 0.61 m per second. Where cyclone separators are provided, gas velocities can occur at more than three feet per second can be used to collect and return the sand. It however, it is generally more desirable to keep the speed in the range of about 0.15 to 0.45 meters per Second hold.

The product mixture from the chlorination zone is passed into vessel A through line 2. This product stream essentially contains 1,1,1-trichloroethane and unreacted 1,1-dichloroethane. and accompanying by-products, primarily hydrogen chloride and minor proportions of others. By-products. The vessel A is preferably without packing. However, it can be filled with any suitable large surface area material, such as packing rings, if desired. At least some of the heavy by-products in the thermal chlorination product stream, e.g. B. 1,1,2-trichloroethane are removed from the boiler via line 18 and some of the heat is removed from the stream. The cooled stream from Kesselt is passed via line 3 to condenser B and at least partially condensed. The partially condensed stream of the condenser B is passed into a separator M , and the hydrogen chloride formed in the chlorinator is removed via line 6a. This hydrogen chloride is used to meet the hydrogen chloride requirement of the hydrochloride.

Stage b)

The partially condensed stream is then passed from the separator M to the forward column via line 4. The chlorination product liquid passed via line 4 is introduced into the upper part of column I. The thermal chlorination product liquid is preferably composed of 1,1-dichloroethane, 1,1,1-trichloroethane and minor amounts of hydrogen chloride and other by-products. Part of the liquid condensed in the separator is sent to the vessel A to create the cooling liquid.

Stage c).

Looking now at the hydrochlorinator N, it is a reaction vessel which is equipped to handle corrosive materials such as hydrogen chloride. This boiler is preferably constructed from steel or a similar material

ίο and can be lined with glass or polytetrafluoroethylene. Vinyl chloride is introduced into the lower part of the hydrochlorinator via line 5. The vinyl chloride can be introduced at ambient temperatures or it can be preheated to about 37.8 ° C. Substantially gaseous hydrogen chloride is introduced into the hydrochloride via line 6. The hydrogen chloride can be introduced separately into the hydrochloride, but is preferably premixed with the vinyl chloride. This hydrogen chloride is preferably obtained at least partially from the hydrogen chloride formed in the chlorination zone. In a preferred embodiment, essentially all of the hydrogen chloride requirement is covered by the hydrogen chloride generated in the system itself. To achieve good conversion of the vinyl chloride _: a molar excess of hydrogen chloride should be used. In mole percent, this excess can be in the range up to 150 and preferably from about 50 to 100%

Lie in excess. A Friedel-Crafts catalyst, such as aluminum chloride or ferric chloride, is placed in the hydrochloride before starting the process. Iron chloride is preferably used. The reaction temperature in the hydrochlorator ranges from about 37.8 to 93 ° C, and preferably from about 57 to 65 ° C. The pressure in the hydrochlorination zone ranges from ambient to about 8.03 kg / cm ^2, and preferably about 1 , 35 to 2.41 kg / cm ² . The mixture in the hydrochloride is essentially a liquid phase mixture which is composed of the reactants, the catalyst and the products and combined by-products produced therein.

Stage d)

The hydrochlorator product stream is used as steam withdrawn from the hydrochlorinator via line 7 and introduced into the condensation zone C. This The condensation zone can be a single or multi-stage arrangement of condensers in which the Hydrochlorination product stream at least partially condensed. The hydrogen chloride is over Line 6 c withdrawn and fed back to the hydrochloride. The hydrochlorination product stream is composed of 1,1-dichloroethane, unreacted vinyl chloride and hydrogen chloride and small Amounts of by-products such as 1,1,2-trichloroethane. The uncondensed part can leave the system

'Discharged or the hydrochlorinator via line 6c

are fed. . . '

; Stage e) '■' ,. .:.,. '■'.

The liquid part of the hydrochlorination product stream is withdrawn from the condensation zone C via line 8 and passed into column I.

The column I is a distillation column, equipped with an evaporator E and an overhead condenser D and distillation media or distillation

lation floors equivalent facilities, such as packages. The first runnings are withdrawn from column I via line 9. This stream is primarily composed of hydrogen chloride, vinyl chloride, 1,1-dichloroethane and small amounts of other compounds. The hydrogen chloride of the first column overhead stream is optionally fed back to the hydrochloride and the higher-boiling constituents are returned to the column. The bottom products from column I are drawn off and introduced into column II via line 10. This stream is composed primarily of 1,1,1-trichloroethane, 1,1-dichloroethane and small amounts of other by-products. The column II is a distillation column equipped ■] with a reboiler / f, a capacitor G and distillation trays or distillation trays equivalent means. .

The wakes are from the. Column II withdrawn via line 11. The composition of the Follow-up sump products are primarily 1,1,2-trichloroethane and smaller amounts of other "by-products. This stream is discharged or in others Investment opportunities used. The overhead stream from column II is withdrawn via line 12 and at least partially condensed in the condenser G. -

Level f):. · ■ ■■ ·. ■ · ..

The resulting condensate is introduced into column III via line 13. The feed to column III is primarily composed of 1,1-dichloroethane and 1,1,1-trichloroethane. The column III is a distillation column equipped with a heater //, an overhead cooler J and equipped with distillation trays or equivalents, such as packings. . · ...

The bottom stream of column III is drawn off via line 14. The stream consists essentially of pure 1,1,1-trichlorethylene. This stream is cooled and transferred to a product storage area. The overhead stream from column III is withdrawn via line 15 and at least partially condensed in the condenser / and transferred via line 16 to the preheater K and then passed from the preheater via line 17 to the thermal chlorinator in stage a). This overhead stream from column III is primarily composed of 1,1-dichloroethane and smaller amounts of other chlorinated hydrocarbons. V The following example explains the invention:

: ■ '■■ · ■ · ■■ · ■■■■ Example

In the following example the process equipment, the piping system, reactors, condensers and similar set up in the same way, as shown in the drawing, unless otherwise stated.

■■ ·· ■ "■ ^; '■■' · ■ '··· ■ ■ ■■ Level a) ■■ · ■■■ ···' ■■ '- ■' ■ ·· ■■ '

Gaseous chlorine was premixed at a temperature of 26.7 ⁰ C and a pressure of 5.22 kg / cm ² with the overhead stream of the product column and the mixture thus formed is introduced into a reaction vessel and thermal Chlorierkessel. The thermal chlorination kettle was previously charged with Ottawa sand, which was suspended under normal working conditions (in the flowing state). The feed to the thermal chlorinator and the overhead products of column products were preheated to a temperature of 204 ⁰ C in an oven prior to mixing with the chlorine feed. The temperature in the fluidized bed chlorination zone was stabilized at 371 ° C and the pressure was 4.52 kg / cm ² . For the duration of the continuous operation it was not necessary to add or remove heat from the thermal chlorinator, in other words, the chlorination step

ίο was essentially adiabatic.

The reaction system turned off at about 357 ° C withdrawn from the thermal chlorinator and introduced into a cooling drum in which the temperature of the Material was cooled to about 107 "C. The partial Chilled stream was passed from the chill drum into a water-cooled condenser, in which the stream was partially condensed. The partially condensed Electricity was passed from the cooler into a separator where the non-condensable parts removed. These non-condensable parts, composed primarily of hydrogen chloride, were withdrawn from the separator and fed to the hydrochloride. The one returned to the cycle Hydrogen chloride from the separator formed a large part of the hydrogen chloride feed requirement for hydrochlorination.

■ level b)

The condensed stream, consisting essentially of 1,1,1-trichloroethane and 1,1-dichloroethane, was derived from the separator and fed back to the cycle in the upper part of a forward column. Part of the liquid in the separator formed the cooling liquid for the cooling drum.

Stage c)

The vinyl chloride was premixed with a stream of hydrogen chloride at a temperature of 26.7 ° C. and a pressure of 4.23 kg / cm ^{2 and placed in a hydrochlorination kettle.} initiated. Under normal working conditions, essentially all of the hydrogen chloride requirement was satisfied by the hydrogen chloride formed in the system itself. During the continuous operation, the hydrochloride contained a liquid phase which was composed of the reactants, products and the ferric chloride catalyst. The build-up catalyst was added to the hydrochloride in small amounts. The temperature in the hydrochlorination reaction zone was 61 ^° C. and the pressure was 2.05 kg / cm ² .

Stage d)

The hydrochlorination product vapors, consisting essentially of 1,1-dichloroethane, vinyl chloride and hydrogen chloride, were withdrawn from the head of the hydrochloride, passed through a kettle, which intercepted the polymeric materials, and passed into a condensation zone, which consists of two condensers was formed. The material contained in the stream, such as hydrogen chloride and smaller quantities other materials, were considered pressurized Steam removed and fed back to the hydrochloride.

Stage e) ■

The material condensed in the condensation zone (essentially 1,1-dichloroethane and vinyl chloride) was introduced into a forward column. It

was a bottom distillation column equipped with an overhead cooler and a steam reheater. The condensed material from the hydrochloride was introduced into the column near the bottom.

The condensed stream from the thermal chlorination condenser was also introduced into the head column near the bottom. The head column overhead vapors (predominantly hydrogen chloride) were fed back to the hydrochloride and the bottom products from the head column were returned to the tail column. The tail column was a bottom distillation column equipped with an overhead condenser and a steam reheater. The feed for the head column was introduced approximately in the middle. During the working conditions, the temperature of the bottom was 121 ⁰ C and _N products. that of the top products 71 ° C. The head pressure was 1.35 kg / cm ² . The bottom products from the follow-up column (essentially 1,1,2-trichloroethane) were drawn off and made available for disposal. The top products (essentially 1,1,1-trichloroethane and 1,1-dichloroethane) of the tail column were condensed.

Stage f)

The resulting condensate, consisting essentially of 1,1,1-trichloroethane and 1,1-dichloroethane, was introduced into the product column. The products column was a tray distillation column, operating at surface temperatures of 93 ° C and a head temperature of 66 ⁰ C. The column was equipped with a steam reheater and an overhead condenser or condenser.

The material from the top of the product column, which consists essentially of 1,1-dichloroethane, was condensed, preheated and charged to the thermal chlorinator. Essentially Pure 1,1,1-trichloroethane was obtained as the bottom product from the first column tray of the product column withdrawn, condensed and taken to storage.

82.0% vinyl chloride feed to the hydrochlorination zone were in 1,1,1-trichloroethane (based on moles of vinyl chloride feed and moles recovered 1,1,1-trichloroethane) implemented. .

Analysis of the product showed that it was 99.30 mol percent 1,1,1-trichloroethane, 0.31 mol percent 1,1-dichloroethane, Contained 0.35% by volume of trichlorethylene and 0.04% of cis-1,2-dichloroethane.

Claims (1)

Claim: Process for the production of 1,1,1-trichloroethane, characterized in that man a) Chlorine with 1,1-dichloroethane preheated to 37.8 to 260 ° C in a molar ratio of 0.2: 1 to 0.7: 1 in a fluidized bed of fine sand at about 316 to 427 ° C and a pressure of about 1 to 15.1 kg / cm ^{2 is} reacted in a known manner in a chlorination device (L), the product mixture consisting essentially of 1,1,1-trichloroethane, 1,1-dichloroethane and hydrogen chloride being cooled in a kettle (A) , at least partially condensed in a condenser (B) and the hydrogen chloride is separated off in a separator (M) and fed to a hydrochlorination device (stage c), b) a portion of the substantially 1,1,1-trichloroethane and 1,1-dichloroethane existing condensate of the chlorination stage a) in the introduces the upper part of a column I and simultaneously with the processes in stage a) and b) c) vinyl chloride and hydrogen chloride, the least partly from stage a) originates in a manner known per se in a hydrochlorination device (N) subject to hydrochlorination conditions, d) the gaseous product mixture obtained in c), which consists essentially of 1,1-dichloroethane, vinyl chloride and hydrogen chloride, at least partially condensed in a condenser (C), the hydrogen chloride produced separated off and returned to the hydrochlorination device (stage c), e) the liquid product mixture obtained in d) passes into column I, a product consisting predominantly of hydrogen chloride is distilled off from column I and optionally returned to the hydrochlorination device (stage c) and the bottom product, which consists essentially of 1,1,1- Trichloroethane and 1,1-dichloroethane is fed to a column II, a bottom product from column II, which consists essentially of 1,1,2-trichloroethane and an overhead product (essentially 1,1,1-trichloroethane and 1,1 -Dichloroethane) is withdrawn, the top product is at least partially condensed in a condenser (G) and f) the condensate obtained in e) is fed to a column III, pure 1,1,1-trichloroethane is withdrawn from column III as bottom product and the overhead product consisting essentially of 1,1-dichloroethane is at least partially condensed in a condenser (J), then transferred to a preheater (K) and then returned to the chlorination stage a). 1 sheet of drawings 409 622/473