DE1518766B1 - Process for the production of 1,1,1-trichloroethane - Google Patents

Description

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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 pure 1,1,1-trichloro-like material from column III. A problem that often arises is that it withdraws as the bottom 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 a capacitor (/), then in a preliminary removal. Another difficulty that occurs is transferred to the heater (K) and then the contamination of the product with catalyst _ chlorination stage a) is returned,
material. Surprisingly, it was found that when driving, such impurities should be removed or reduced because they are byproducts of the 1,1,1-trichloroethane responsible for the process according to the invention only to a small extent. The procedure has also been loaned. the advantage that it lasts for a long time

In the effort to over-

wind, the industry often does not have the option of decommissioning the plant for cleaning

Complicated and expensive extraction process to the ab-.

separation of 1,1,1-trichloroethane from other halo- The inventive method looks from the

genated hydrocarbon impurities genome introduction of 1,1,1-trichloroethane into the hydro

men. Likewise, the prior art often eliminates and thereby avoids chlorinating equipment

maize uses expensive equipment, which results in a loss of 1,1,1-trichloroethane yield

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 the fact that "

a) Chlorine with 1,1- ^{diaphragm preheated to 37.8 to 26O 0 C a)}

chloroethane in a molar ratio of 0.2: 1 to 0.7: 1 in chlorine is in the chlorination zone via line 1 a fluidized bed of fine sand at about 316 together with a preheated 1,1-dichloroethane to 427 ° 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 pre-mixed product and hydrogen chloride creates a reaction in which the reaction cools down in a boiler (A) , is thermodynamically at least partially condensed in an equilibrium system (B) in such a way that it is unnecessary to add heat to the hydrogen chloride in a separator (M) or to remove excess heat from the reaction and remove it from a hydrochlorination zone. It is necessary to feed the 1,1-dichloro apparatus (stage c), ethane feed to a temperature of 37.8 to

b) some of the essentially 1,1,1-trichloro 45 260 ⁰ C preheat. A more preferred heating ethane and 1,1-dichloroethane existing con temperature is from about 149 to 232 ° C, because under the densates of the chlorination stage a) in the upper these conditions the formation of by-products introduces part of a column I and is simultaneously reduced and high Yields can be achieved. The processes in stages a) and b) are fed to the chlorination zone 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 a hydrochlorination device in a manner known per se in the range of 0.2: 1 Subject to (N) up 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 55 feri, is 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 the column I passes, from column I a sufficient to the stabilized reaction within the To create a Pro-Zone consisting predominantly of hydrogen chloride. The chlorination reaction in the fluid duct distilled off and, if necessary, in the bed is at a uniform temperature in the ge-hydrochlorination device (Stage c) recirculates 65 entire fluidized bed from about 316 to 427 ° C and preferably

■ and the bottom product, which is essentially from wise at a temperature of about 243 to 399 ⁰ C

1,1,1-trichloroethane and 1,1-dichloroethane are stabilized. The reaction is controlled by about atmospheric

a column II supplies, from column II apparent pressure up to 15.1 kg / cm ² and preferential

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wisely carried out up to 5.92 kg / cm ^2. A discharged liquid is fed to the boiler A in order to create the working pressure recorded is around 3.81 to 5.22 kg / cooling liquid.
cm ² , with an additional pressure to transfer the "

Electricity back to the hydrochlorinator is not required- ^c '

is borrowed. 5 If one now looks at the hydrochlorinator ./V,

Although the chlorination is usually preferred, this is a reaction vessel that is equipped in such a way that Adiabatic chlorination, as described above, is that corrosive materials such as hydrogen chloride can the inventive method can also be handled under. This kettle is preferably non-adiabatic Conditions are wisely constructed of steel or similar material d. h ,, Heat can be supplied or taken from the reaction and can be embedded in glass or polytetrafluoroethylene removed. The fluid bed in this chlorine-clad. Vinyl chloride is in the lower part of the tion zone is composed of fine sand, introduced into hydrochlorinator via line 5. The Viden the gases are directed and converted. For nylchlorid can be achieved at ambient temperatures For best results, the sands should be passed, or it can advance down to about 37.8 ° C essentially free of nickel and iron and their 15 are heated. Essentially gaseous chlorine compounds be. The gases are fed into the bed with hydrogen being fed into the hydrochlorinator via line 6 introduced at such a rate that one initiated. The hydrogen chloride can be separated into the good fluidized bed process and an equally good hydrochlorinator will be initiated, but will prefer heat transfer the reaction gases are premixed with the vinyl chloride on the sand. Preferred. The only limitation on wise this hydrogen chloride becomes at least partially the speed of the incoming gases is due to the chlorodarin formed in the chlorination zone, that the speeds obtained with the hydrogen used. In a preferred embodiment The type of sand and the type of reactor used are essentially all of the chlorine-compatible must be. To create the appropriate hydrogen requirement through the self-generating flow ability in the system for fine sand it is generally covered by 25th hydrogen chloride. To prefer a good conversion, Reaching the surface velocity of the in lung of vinyl chloride should be a mol-die Gases entering the reaction zone are used with an excess of about 0.03 hydrogen chloride, to hold up to 0.61 m per second. Where cyclone separators- In mole percent, this excess can range up to which are provided, gas velocities up to 150 and preferably from about 50 to 100% more than 0.61 m per second are used, there is an excess of 30. A Friedel-Crafts catalyst, like to collect the sand and bring it back. It aluminum chloride, or ferric chloride, is used in the however, it is generally more desirable to run the Ge Hydrochlorinator on before starting the process in the range of about 0.15 to 0.45 m per brought. Preferably ferric chloride is used. Second hold. The reaction temperature in the hydrochloride is in

The product mixture of the chlorination ^{zone is passed in the range from about 37.8 to 93 0} C and preferably through line 2 into the boiler. This process about 57 to 65 ⁰ C. The pressure in the containing approximately Hydrochlorieduktenstrom zone substantially 1,1,1-trichloro is in the range of ambient pressure to ethane and unreacted 1,1-dichloroethane and about 8.03 kg / cm ² and preferably from about 1.35 to attendant by-products, primarily chlorine- 2.41 kg / cm ² . The mixture in the hydrochloride is essentially a liquid phase mixture in the hydrogen and minor proportions of the other 40, which results in by-products. The kettle A is preferably composed of the reactants, the packing. It can, however, if desired, with any catalyst and the products made herein, a suitable high surface area material, and combined by-products. .

like packing rings. At least one. .

Part of the higher-boiling by-products in the 45 ^{btute d)} . ".

mix chlorination product stream, e.g. 1,1,2-tri- The hydrochlorination product stream is used as steam

chloroethane, are withdrawn from the kettle via line 18 from the hydrochlorator via line 7 and some of the heat is introduced from the stream and into condensation zone C. This removed. The cooled stream from boiler A to the condensation zone can be conducted in a single or multiple manner via line 3 to condenser B and be a few-stage arrangement of condensers, in which the condenser is at least partially condensed. The partially condensed hydrochlorination product stream, at least part of the stream of the condenser B , is condensed in a separator M. The hydrogen chloride is passed over and the chlorine line 6 c formed in the chlorinator is drawn off and hydrogen is removed again from the hydrochloride via line 6 a. This chlorine-supplied. The hydrochlorination product stream is hydrogen and is used to meet the hydrogen chloride level, composed of 1,1-dichloroethane, which is not required by the hydrochloride. put vinyl chloride and hydrogen chloride and small

Amounts of by-products such as 1,1,2-trichloroethane. Stage b) The non-condensed part can be removed from the system

discharged or the hydrochlorinator via line 6c

The partially condensed stream will then be fed from 60. . .

the separator M to the flow column via Stuie e)

Line 4 headed. The chlorination product liquid passed via line 4 is introduced into the upper part of the liquid part of the hydrochlorination product column I. The thermal chlorination product stream is withdrawn from condensation zone C via lead liquid, preferably from 1,1-dichloroethane, 65 device 8 and introduced into column I.
1,1,1-trichloroethane and smaller amounts of chlorine- The column I is a distillation column, hydrogen and other by-products together with an evaporator E and an overhead set. Part of the condenser D condensed in the separator and distillation agents or distillation

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Equivalent facilities, such as Pak overhead products of the product column, were opened. The first runnings are drawn off from column I above a temperature of 204 ^° C. in an oven upstream of line 9. This stream is primarily preheated to mix with the chlorine feed. The composed of hydrogen chloride, vinyl chloride, temperature in the fluidized bed chlorination zone, 1,1-dichloroethane and smaller amounts of other compounds were stabilized at 371 ° C. and the pressure was 4.52 kg / compounds. The hydrogen chloride of the first column- cm ² . During the duration of the continuous working overhead stream, it may not be necessary to add heat to the hydro-chlorinator and to return the higher-boiling components to the column or to remove them from the thermal chlorinator. The sump far, in other words, the chlorination products from column I are withdrawn and in io was essentially adiabatic. Column II initiated via line 10. This stream of the reaction system was drawn off at about 357 ° C, primarily from 1,1,1-trichloroethane, 1,1-dichloro-the thermal chlorinator and introduced into an ethane and small amounts of other by-products cooling drum, in which the temperature composed of. Column II is a distillation material that has been cooled ^{to about 107 ° C.} The partial column, equipped with a reheater F, 15 wise cooled stream was passed from the cooling to a condenser G and distillation trays or drum into a water-cooled condenser, in distillation trays equivalent means. which the stream was partially condensed. The part of the tailings are drawn off from column II via condensed stream from the cooler into a discharge line 11. The composition headed to the separator where the non-condensable trailing bottom product is primarily 1,1,2-tri-20 has been removed. These non-condensable parts, chloroethane and smaller amounts of other by-products, primarily composed of hydrogen chloride, products. This stream is discharged or has been withdrawn from the separator in others and used in the plant options. The overhead stream is fed to the hydrochloricator. The cycle again from column II is withdrawn via line 12 and hydrogen chloride fed in from the separator is at least partially condensed in the condenser G and a large part of the hydrogen chloride charge is condensed. requirements for hydrochlorination.

Level f) Level b)

The resulting condensate is via line 13 in The condensed stream, consisting essentially Column III initiated. The feed of 1,1,1-trichloroethane and 1,1-dichloroethane to the colon 30 was nelll is primarily derived from 1,1-dichloroethane and from the separator and the cycle im

Composed of 1,1,1-trichloroethane. The column III is fed back to the upper part of a forerun column,

is a distillation column equipped with a part of the liquid of the separator formed the

Heater H, an overhead cooler / and equipped cooling liquid for the cooling drum,

with distillation trays or equivalents, such as antitank _t 35 _Oi -.

kungen. ^{Stage c)}

The bottom stream of column III is drawn off via line The vinyl chloride was drawn off at a temperature of 14 device. The stream consists essentially of 26.7 ° C. and a pressure of 4.23 kg / cm ² with a pure 1,1,1-trichloroethane. This stream is premixed with a hydrogen chloride stream and passed into a hycooler and into a product storage area above the hydrochlorination tank. Led under normal. The overhead stream from column III was essentially withdrawn via line 15 and at least partially the entire hydrogen chloride requirement was satisfied by the hydrogen chloride formed in the system condensed in the condenser / and via line 16 itself. While transferred to the preheater K and then from that of the continuous working process, the preheater contained a liquid phase via line 17 to the thermal ChIo- 45 hydrochloride, which passed out of the rierer in stage a). This overhead stream of the reactants, products and the iron chloride column III is primarily composed of 1,1-dichloroethane catalyst. The build-up catalyst and smaller amounts of other chlorinated carbon were combined in the hydrochloride in small amounts of hydrogen. admitted. The temperature in the hydrochlorination

The following example explains the invention: 50 reaction zone was 61 ^° C. and the pressure was 2.05 kg / cm ² .

Example stage d)

In the example below, the method consisting of the hydrochlorination product vapors

rene equipment, the piping system, reactors, Kon- essentially made of 1,1-dichloroethane, vinyl chloride condensers and the like in the same way - 55 and hydrogen chloride, were set up from the head of the hydro, as can be seen from the drawing, if the chlorinator has been removed, passed through a boiler, nothing else is stated. which intercepted the polymeric materials, and into a

Condensation zone passed, which was formed from two condensers stage a) sators. That contained in the stream

Gaseous chlorine was removed at a temperature of 60. Material such as hydrogen chloride and minor amounts of 26.7 ° C and a pressure of 5.22 kg / cm ² with that of other materials were removed from the product column as a pressurized overhead stream and vapor mixed in again with the hydrochlorinator and the mixture thus formed is fed into a reactor,
tion boiler or thermal chlorination boiler initiated. Stage e)

The thermal chlorination boiler was previously rated at 65

Ottawa sand is charged, which under normal work- The condensed material in the condensation zone

conditions (in the flow state) was suspended. The material (essentially 1,1-dichloroethane and vinyl feed for the thermal chlorinator or the chloride) was introduced into a forward column. It

was a bottom distillation column equipped with an overhead condenser 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. While working conditions, the temperature of the bottoms 121 ⁰ C and the overheads 71 ° C. The pressure at the top 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 was in 1,1,1-trichloroethane (sourced on moles of vinyl chloride charge and moles of 1,1,1-trichloroethane recovered).

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

Claims (1)

Claim: Process for the production of 1,1,1-trichloroethane, characterized in that man a) with chlorine to 260 ° C preheated to 37.8 1,1-dichloroethane in a molar ratio from 0.2: 1 to 0.7: 1 in a fluidised bed of fine sand at about 316-427 ⁰ C and a pressure of about 1 up to 15.1 kg / cm ² in a chlorination device (L) in a manner known per se, which cools the product mixture consisting essentially of 1,1,1-trichloroethane, 1,1-dichloroethane and hydrogen chloride 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) part of the consisting essentially of 1,1,1-trichloroethane and 1,1-dichloroethane Introduces condensate of the chlorination stage a) into the upper part of a column I and at the same time as the processes in stages a) and b) c) subjecting vinyl chloride and hydrogen chloride, at least in part from stage a), to hydrochlorination conditions in a hydrochlorination device (N) in a manner known per se, 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), consist of 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, from column I. predominantly consisting of hydrogen chloride product distilled off and optionally in the hydrochlorination device (stage c) recirculates and the bottom product, which is essentially consists of 1,1,1-trichloroethane and 1,1-dichloroethane, a column II supplies, from the column II a bottom product that is in consists essentially of 1,1,2-trichloroethane and a top product (essentially 1,1,1-trichloroethane and 1,1-dichloroethane), 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 (/), then transferred to a preheater (K) and then returned to the chlorination stage a). For this 1 sheet of drawings 109 519/382 COPY ϊ