DE1468480B - Process for the production of 1,2-dichloroethane which is very pure with respect to chloral - Google Patents

Description

Cl O O Cl

Cl - C - C - H -.- NaOH -> NaO - C - H (Cl - C - H (1)

Cl Cl

Cl OH O Cl

Cl-CCH 'NaOH --- NaO C-H, -Cl-C-H; H ₂ O (2)

Cl OH Cl

The 1,2-dichloroethane product treated in this way as the top fraction in the form of a very pure stream can then easily be removed in a conventional 1,2-dichloroethane.
Distillation plant through simple fractionation Oxychlorination «, through which the invention

are distilled whereby very pure 1,2-dichloroethane according to chloral-containing 1,2-dichloroethane is obtained which are produced essentially free of chloral s, can be carried out according to processes, both in r-form of chloral and in the form, such as _{it is written in step 1 261 m} in the German interpretation of chloral hydrate. So made

According to the prior art it is known that 1,2-dichloroethane streams contain at the end small amounts of 1,2-dichloroethane in the presence of alkali metal chloral amounts, ie amounts of 0.2 to 3%, hydroxide solutions easily with the formation of vinyl ίο based on the weight of the chlorinated carbon chloride can be dehydrochlonert, according to hydrogen flow. However, it is also possible to use the following equation: _{products> which are produced by other} oxychlorination processes

were produced, e.g. B. to use the fixed bed process.

H H '5 In a preferred embodiment of the invention

sodium hydroxide solutions are used in the

_r | QQ Q ^ v ₁ OH ral distance level used, where the conc

tration between 5 and 20 percent by weight of "sodium

_HH hydroxide, preferably S to 15 percent by weight.

20 lie. The temperature in the contact or cleaning zone, in which the sodium hydroxide with the

H H contaminated liquid 1,2-dichloroethane in contact

tion is brought, is preferably between 38

- > H —CC-Cl NaCl Η., Ο (3) and 49'C. In the preferred embodiment of the

25 present invention contains the packed column, in which the contact occurs. Substances such as packing rings to ensure adequate contact between 1,2-di-

Such processes are guaranteed in the USA patent chloroethane and caustic soda. A documents 2 539 3'7 and 2 041814 are described. It packed column is preferred, however, although used, is surprising that erfindunpsgemä can be "the Chloralgehalt _3O also columns with sieve bottom, a 1,2-Dichloräthanstromes by treatment with columns with a Fraktionierbodenglocke and other a Alkahmetallhydroxydlöiung H _e i moderate tem- similar columns, in which liquids in contact temperatures can essentially be removed. can be brought together,
without the formation of vinyl chloride at the same time. During the operation of such a system, water

the aqueous Alkalimetallhydroxydlösungen with _{35 r} i _ges sodium hydroxide in "stand the lower part of 1,2-dichloroethane in contact, contact or purification column 'is passed, the according to the present invention in the essential contaminated 1,2-dichloroethane. A vinyl chloride does not come down the column, which trickles because of the slide, while the sodium hydroxide could be expected from below chung (3)

That used in the inventive method ₄₀ of 1,2-dichloroethane as a bottoms fraction from the Kon hydroxide is preferably sodium hydroxide. When the clock tower is removed, while the aqueous sodium operation of the inventive contact or pure hydroxide phase is derived as the top fraction, it is important that the specified temperature range is strictly adhered to, with the two liquids passing through, as when through the columns, in countercurrent Temperatures that are flowing to one another, outside this range, ₄₅ touch. If one proceeds in this way, ie higher temperatures, the 1,2-dichloroethane which is cracked by the conversion of the sodium hydroxide to vinyl chloride and thus 1,2-di- chloroform formed with the chloral is lost with the chloroethane. The alkali metal - Removed organic liquid, while hydroxide concentrations are within the specified, the sodium limits resulting from the reaction and the temperatures in the above-mentioned formate, which is kept rich in the aqueous caustic solution when the contaminated 1,2-dichloro is soluble is, in the aqueous top fraction stream of ethane and the alkali metal hydroxide solutions in this column is removed.

are moved, a satisfied result is obtained. In Petroleum Refiner, November 1957, p. 239 is

Establishing reduction of the chloral content in 1,2-Di- described a process in which the chloroethane and no formation of vinyl chloride. 55 ration of ethylene in the liquid phase was created from the alkali metal hydroxide contact zone which liquid Progewonnene containing 1,2-dichloroethane organic product is preferred. treated with 6-8% alkali lye passed into a dehydration column before it becomes the. In such a manufacturing process Distillation column is fed, in which the end product develops, however, in contrast to the oxychlo. The 1,2-dichloroethane is no chloral after 60 ration, so that the one described there it with the alkali metal hydroxide solutions / ur de- treatment with an alkali lye not the removal of the chloral contained in it is treated fenuing by chloral. Task of the present was passed into a dehydration column, but it was an invention. Chloral from the reaction gas to remove the water contained in the organic stream.

distant. It is normally referred to in dehydration 65 From U.S. Patent 2,589,212 the water as the top fraction is removed while the raw 1,2-dichloroethane is known by washing with to purify the organic matter from the soil to a dcstil- alkaline solutions. With this Vcrlicrsäule is passed, from which the 1,2-dichloroethane drive, however, the 1,2-dichloroethane entlial-

An aqueous sodium hydroxide stream is passed through the drilled holes and into the

solution was added to form an aqueous phase, the vessel was up to a height of

before the Keajaiuuag R ";cni> l ι _a heqrhrirhen κ" contained in the 1,2-dichloroethane stream

Acid has been removed from the stream. The sodium 1.83 m with the as described in Example 1 a her-

hydroxide was added here to fill the 5 existing catalyst layers Dre, Q ^.

To remove or neutralize acid. In the case of loading _{trolleys, the E ^ π§}

Such a process is a multiple of the oxygen, ethylene and chlorine and / or HCl η den

in the method according to the invention, in which the orga- wind boxes ^vo f * ^ehen _nn ^E , ^m * "J ^ S _n ' tV ?

niche liquid phase before the treatment with a 15.25 m long η ιand 1.27 m thick nod -

Alkali was removed from the aqueous, acidic phase, was at one point in the U.rbel-

separates, required amount of alkali required. layer attached that! about υ ι »m °° e ™ a id over

A similar procedure is laid in U11 m a η η s distribution plate, and it extended about ι, 98 m

Encyclopedia of Technical Chemistry, third up. Water that is under a pressure of

location, Volume S, p. 421, middle. Here is 2.1 kg / cm ² if you walked around in the queue

a Resulting by chlorination of ethylene, _l5 lose, so that the heat has been derived by

90 "/ ₀ dichloroethane-containing product with water takes place in the fluidized bed reaction

and then washed with soda solution without being generated.

that previously there was a separation between organic and When using this ar-arates were atria,

aqueous phase took place. HCl and oxygen in a single molar ratio

For a better understanding of the invention, ₂₀ ethylene to HCl to oxygen from 1.0 to 2 03 zi. 0, d8

the following examples initiated certain types of processes in the reaction vessel. The temp- ^ tur

explain that in the process according to the invention the reaction vessel was geiv.iten to 288 C,

are possible while a layer speed of 18.3 cm, bek.

was maintained. Those of the reaction. ^ Efäß

If 1 1 escaping product gases were released by a ..

a) Manufacture of the catalyst with a jacket and tube consisting of heat

A catalyst consisting of an aqueous solution was passed, and the organic product was produced by condensing 13.166 kg. The condensed h · g-CuCU · 2 H, 0 and 6.901 kg KCl in 20.06 liters of distillation were then passed into a phase separator, where the precipitated water dissolved. A reaction vessel with a niche from which water and the vented width of 25.4 cm was separated with 45.4 kg of HCl. If it is filled in burnt fuller's earth, which has a particle size in this way, one obtains a 1,2-Dichloraüianaufwies that it passed a sieve with a clear mesh crude product with a degree of purity of 9;, 5% width of 0.246 to 0.543 mm. The fuller 1,2-dichloroethane when using ethylene and earth particles were in the reaction vessel to 35 HCl of 93.4 and 93.5 ° / _0, respectively.

gewirbe't by blowing hot air through the 45.4 kg of the organic product that predominantly consists of

Particles of the layer having a surface speed of 1,2-dichloroethane contained about 0.5 Gev. lightness of 0.153 m / sec. blew up from below. percent chloral (CCl ₃ CHO). The layer ^{temperature was kept at 104 0} C. The impure 1,2-dichloroethane raw material was then fed in and the solution containing the catalyst was passed the upper section of a glass column, which was added dropwise to the layer until the whole was an inner one Diameter of 0.11 cm, a height of 20.06 ι solution were added. The reaction vessel had a height of 3.66 m and was shut down at a height of 3.05 m when no water of solution was filled. The filling consisted of 0.64 cm thick catalyst solution more than the top fraction escapes. Rings made of ceramic, the column was constantly filled with The finished catalyst contained 7.5 percent by weight of a 10 percent by weight aqueous sodium hy-copper and 5.5 percent by weight of potassium. droxydlösung flows through as a continuous phase.

The caustic solution was introduced at the bottom

b) Oxychlorination and recovery of very pure _{imd at the tip of the foot U} ng removed again. Crude 1,2-dichloroethane 1,2-dichloroethane, which is at the top of the column

A reaction vessel made of nickel with a height of 50 was removed again at the bottom, dried in a dehydralisierdestilliersänle of 2.44 m and a diameter of 0.38 m and was fractionated as an oxychlorination fluidized bed reactor in a second column. During the turns. The reaction vessel was enclosed by contact, the temperature of the column was kept at 46 ° C with a steel jacket with a diameter of. The derived 1,2-dichloroethane product 0.51m, which had an annular heat exchange system 55, had a degree of purity of 99.5%. While forming, in which the heat transfer medium used in the experiment, diphenyl diphenyloxide eutectic introduced per tonne of the column was used to heat crude 1,2-dichloroethane 7.006 kg of NaOH, and to cool the fluidized bed. The 1,2-dichloroethane treated inside a solution with the caustic upper part of the reaction vessel was removed from the column, only nickel cyclone with a diameter of 0.20 m contained 60 traces of chloral (0.02% or less),
arranged. At the bottom of the reaction vessel was .... · ■. 1 7

a distributor plate made of nickel with a large number of Ii e 1 s ρ 1 e I L

arranged with drilled holes. Using the method described in Example 1b below the

There was a cooling plate on the sides and on the lower reaction vessel were ethylene, HCI and Floor closed, wind box or chamber, 65 oxygen in the molveihälliiis of ethylene to HCl which converted as an introduction chamber for the as reaction to oxygen from 1.0 to 2.03 to 0.58, Participant acting feed gas served. The temperature of the reaction vessel rose to Feed gases were held in this chamber at about 288 ° C for a shift of

speed of 0.18 m / sec. was applied. The product gases were in one of a jacket and condensed tube existing heat exchanger, the liquid product obtained was in a organic phase and an aqueous phase separated. The organic phase consisted mainly of 1,2-dichloroethane (95 percent by weight) and contained approximately 0.5 percent by weight chloral.

This 1,2-dichloroethane contaminated with chloral was then passed into the upper section of a glass column which had an inner diameter of 0.10 m, a height of 3.66 m and was filled at a height of 3.05 m. The filling consisted of 0.64 cm thick ceramic rings. A 10 percent strength by weight aqueous potassium hydroxide solution was passed through the column as the continuous phase. The potassium hydroxide was introduced at the bottom of the column and removed at the top above the packing. The 1,2-dichloroethane contaminated with chloral was introduced at the top of the column and removed at the bottom. The temperature of the column was kept ^{at about 46 ° C. during the contact.} If this is done, the 1,2-dichloroethane removed from the column only contains traces of chloral (0.02% or less).

Example 3

Using the reaction vessel described in Example 1b, ethylene was added. HCl and oxygen reacted in a molar ratio of ethylene to HCl to oxygen of 1.0 to 2.03 to 0.58. the The temperature of the reaction vessel was maintained at about 288 ° C during one shift speed S of 0.18 m / sec. was applied. The product gases were in one of a jacket and a Condensed tube existing heat exchanger, the resulting liquid product was converted into an organic and an aqueous phase separated. The organic phase consisted mainly of 1,2-dichloroethane (95 percent by weight) and contained approximately 0.5 percent by weight chloral.

This chloral-contaminated 1,2-dichloroethane was then placed in the top of a glass column headed, which had an inner diameter of 0.10 m, a height of 3.66 m and a height 3.05 m was filled. The filling consisted of 3.56 cm thick ceramic rings. The pillar was with a 10 weight percent aqueous

ao ammonium hydroxide solution flows through it, which is introduced at the bottom of the column and at the top above the filling is removed. The 1,2-dichloroethane contaminated with chloral was in the top of the Column initiated and removed below. During the contact, the temperature of the column became low held about 38 ° C. If you proceed in this way, 1,2-dichloroethane is removed from the column which only contains traces of chloral (0.02% or less).

309 546

2697

Claims (3)

Column derives and the 1,2-dichloroethane at the entPatent claim: opposite end removed from the column and, if necessary, then a method for obtaining with reference to 3 the in? 1,2-dichloroethane obtained freed from water chloral very pure 1,2-dichloroethane from a 5 'and optionally worked up by distillation. Crude product that has been produced by oxychlorination from ethylene, chlorine and / or hydrogen chloride and a 1,2-dichloroethane can be produced by oxychlorination of oxygen-containing gas has been produced from ethylene in a fluidized bed reactor, and contains contaminating amounts of chlorine, with gas streams which are predominant 1,2-Dimit containing the principle of washing with aqueous io chloroethane. With such oxychlorination alkaline solutions, characterized by this, modified "Deacon" reactions are used, in which one uses hydrogen chloride as a source of chlorine for the chlorination of the ethylene _{1. The loading} from the oxychlorination is used. It is assumed that product gases are condensed, the organic phase _{that bd such} oxychlorination process separates one from the aqueous phase, then the oxychlorination - catalyst - reaction chamber is added. 2. the organic, chloral-containing phase led hydrogen chloride in the presence of air or in a column, in countercurrent aqueous oxygen is oxidized to chlorine and water and alkali hydroxide solution (concentration 5 to _that ß _s j _c h the chlorine with the ethylene to the ge -20 percent by weight) or ammonium _{hy- 20} desired 1,2-dichloroethane converts,
initiates a hydroxide solution of appropriate strength, if an oxychlorination is carried out for the production of 1,2-dichloroethane from the temperature during the contact ethylene, the temperature is between 10 and 66 ° C, the aqueous fraction at one end of the column derives a _good 1 under moderate reaction conditions, which is extraordinary , 2-dichloroethane yields achieved. In the manufacturing and the 1,2-dichloroethane at ₂₅ counteracted position of 1,2-dichloroethane in the way the translated end removed from the column and the oxychlorination is the product, however, normal optionally then _{we se} j _m j _t Chloraf contaminated. The 1,2-dichloro 3. the chloral containing the 1,2-dichloroethane obtained in 2. from ethane (more than 0.2 weight water freed and possibly percent by distillation), which then works as either Chloral or Chloralmif. 30 hydrate occurs is a serious problem. if the unpurified 1,2-dichloroethane streams are to be distilled. Since chloral and / or chio Boiling ralhydrate in the immediate vicinity of 1,2-dichloroethane, represents a distillation of such streams, 35 in which either one of the two or both sub-The invention relates to a process for the recovery punch are included to achieve a very pure with respect to chloral very pure 1,2-dichloro-1,2-dichloroethane an exceptionally difficult ithan from a crude product, the oxychlo and costly process.
ration from ethylene, chlorine and / or chlorine water- According to the present invention can flow in productitoff and an oxygen-containing gas 40 containing 1,2-dichloroethane, which has been provided by and the contaminating amounts of oxychlorination of ethylene, chlorine and / or HCI contains chloral, produced with the aid of the principle of washing and an oxygen-containing gas with aqueous alkaline solutions, which are easily characterized by the fact that chloral contained is separated off in contaminating quantities. It is therefore τ,. , ~. . . . ,, _,, 45 possible without difficulty in normal distilleries 1. coming from the oxychlorination product _{from lationsverfahren d} £ p _{sen roduklStr} ömen more gases, the organic phase of the condensed _{pure u} _ _{dichloroethane,} ^ determine without separated on aqueous phase, then resorted _{a costly} distillation unit 2. the organic, chloral-containing phase would have to be. Through the Koneine column according to the invention, aqueous alkali 50 tact with an aqueous alkali metal hydroxide solution (concentration 5 to 20 form in the contaminated 1,2-dichloroethane weight percent) or ammonium hydroxide solution introduces current corresponding to one or both of the subsequent corresponding strengths, in countercurrent Temperature equations sodium formate and chloroform, which during the contact between 10 and 66 ⁰ C depends on whether the impurities holds as chloral, the aqueous fraction is contained at one end of the 55 or as chloral hydrate or both.