DE1568839A1 - Separation process - Google Patents

Description

PATE NTAN WALTE
DR.-ING. H. FINCKE DIPL.-ING. H. BOHR DIPL.-ING. S. STAEGER

Telephone: 22 49 41

8 wishes 5, Muil.'rstrasse 31

May 17 '966

Folder 20 734

Case MD.18357/18358

description

to the patent application

of Imperial Chemical Industries Limited London, S. ¥ ₀ l / England

"Separation process"

PRIORITIES? Great Britain May 17, 1965, May 17, 1965 and May 9, 1966

The invention relates to a method for removing Impurities from dilute gases containing acetylene, or acetylene and ethylene, and a method which such impure, dilute gases are used to achieve the desired products *

0098U / 1935

The production of dilute acetylene and aoetylene / ethylene mixtures, in which the dilutions contain hydrogen, carbon monoxide, carbon dioxide, nitrogen and methane, by the combustion of hydrocarbons is known. Such mixtures can be formed by subjecting the hydrocarbon to various process conditions. For example, nethane or gaseous chemicals containing ^: '* Methane can be subjected to partial combustion under controlled conditions of time and temperature and then rapidly quenched to produce a diluted ·· acetylene mixture, as described above, to give which contains very little ethylene. Heavier hydrocarbons, such as λthane, propane and petroleum naphtha, can also be pyrolysed or cracked to produce dilute acetylene / ethylene mixtures with various acetylene / ethylene mixtures, the diluent gases being as described above obtained by injecting a liquid hydrocarbon into hot gases obtained by burning a hydrogen-containing gas in an oxygen-containing atmosphere. Another method is to burn a fuel in an oxygen-containing atmosphere in a furnace that is lined with a refractory material so that the liner is heated to a high temperature} then liquid hydrocarbon is injected into the furnace.

009814/1935

injected with the result that the hydrocarbon is under Formation of the dilute acetylene / ethylene-öemisohes georaokt will.

Solohe dilute aoetylene or aoetylene / ethylene-ßemisohe are old soot, tarry materials and aromatic hydrocarbons such as benzene, contaminated. The first two materials are readily can be removed by Vaeohen with water and oil to remove _t while the aromatic hydrocarbons at least partly by condensation under pressure. However, the dilute acetylene or acetylene / ethylene oemisohe also contain small amounts, for example 0.2 to 3 vol. 1, of hydrocarbons with at least 3 carbon atoms. These impurities are essentially olefinic and aoetylenic hydrocarbons, such as propylene, propadlene (allene), butadiene, methylacetylene, ethylacetylene, vinyl acetylene, di-vinyl acetylene, phenylacetylene, diaoetylene, ethyldiaoetylene and triacetylene.

Solo hydrocarbon impurities that are at least 3 Containing carbon atoms should, however, be removed as they cause serious interference when aoetylene and Ethylene are converted to form the desired products, either duroh poisoning of catalysts or through contamination of products. The hydrocarbon

0098U / 1935

Impurities can be removed to a large extent »by Wash them in a suitable solvent such as paraffin Hydrocarbon solvents kept at a temperature below 0 ° can be absorbed. You hydrocarbon contaminants can then from the raw solvent mixture can be removed by distillation. However, such a procedure requires the use of a large amount of solvent to treat the gaseous mixtures requires intensive cooling equipment and is expensive operational.

It is possible to use methods of operation in which acetylene and ethylene mixtures are purified not only to remove these hydrocarbon impurities, but also the dilution gases; then the pure acetylene / ethylene mixture is then converted into the desired products cheaper sources of dilute aoethylene and
However, it is preferable for acetylene / ethylene mixtures to use these dilute mixtures directly rather than subjecting them to extensive cleaning operations to isolate the pure gases.

The present invention provides a method by which hydrocarbon contaminants are at least «3
Carbon atoms in dilute acetylene or acetylene /
Ethylene mixtures are at least partially removed, domestic

0098U / 1935

BATH ORIGINAL

which the diluted, contaminated mixtures with chlorine in a liquid, chlorinated hydrocarbon medium that acts against chlorine under the conditions of liquid-phase chlorination is inert in the weeklong, be treated with the eo generated chlorinated hydrocarbons of at least 3 carbon atoms essentially in this chlorinated hydrocarbon medium to be held back "

Take the liquid chlorinated hydrocarbon medium as an example »That in the chlorination stage of the invention Process can be used are carbon tetrachloride, aym.-tetrachloroethane, 1,2-dichloroethane (ethylene dichloride) and chlorinated aromatic hydrocarbons such as trichlorobenzene mentioned. Ethylene dichloride is the preferred medium.

In the absence of a Catalyst or in the presence of a metal chloride catalyst, e.g. PerrlChlorid. An industrial one Source of chlorine containing a small amount of oxygen, such as that obtained from the electrolysis of sodium chloride solution obtained can be used.

The chlorination stage is preferably also under excess pressure, e.g. carried out up to 15 at.

0098U / 1935

In the removal of the hydrocarbon impurities, preferably between 1 and 3 mol of chlorine are used per hol Hydrocarbon impurities used · Ib according to the invention Process, the dilution gases in the acetylene or Aoetylen / Äthylen-Oemlsohen not attacked by chlorine.

The chlorinated carbon medium, e.g. ethylene chloride, can be mixed with a considerable amount of chlorinated hydrocarbons of at least 3 carbon atoms (which are formed by the reaction of chlorine with such hydrocarbons), which can be circulated as a reaction, even when used for a long time. The chlorinated medium can then be drawn off and distilled and the purified ethylenic chloride returned to the reaction vessel. Chlorinated hydrocarbons that contain at least 3 carbon atoms, for example those with 3 and 4 carbon atoms, are also obtained by this distillation world. These latter materials are useful to give in a Ohlorolyseeerfahren, where they are treated with chlorine at temperatures in the range of 400 to 700 ⁰ C for carbon tetrachloride and Perehloräthylen · Since "ER, therefore flndungegemäee method 1st also valuable in the undesirable hydrocarbon - impurities in

0098U / 1935

diluted acetylene or acetylene / ethylene mixtures only easily and effectively removed, but also into desirable ones Products can be transferred, in fact, large amounts of acetylene and ethylene, which according to the invention can Processes can be processed which convert eelbet small amounts of these hydrocarbon impurities In the diluted gas mixture there should be large amounts of carbon tetra-carbon and Perohloräthylen yield "

According to a modification of the chlorination stage, the dilute acetylene or acetylene / ethylene mixtures containing the heavy hydrocarbon impurities are first washed with a solvent for the heavy hydrocarbon impurities to remove some of the latter, and the dilute, partially purified Aoetyltn or Aoetylen / Xthylen mixture is gemäü of said GhIοriβrungestufe treated _v to further amounts of these heavy hydrocarbon impurities to remove "with application of such a washing process Äthylendiohlorid for example, can be used as solvents at low temperatures, in the range from -50 ⁰ C to +30 ⁰ C. Such a partial waterlogging process requires less effective removal of heavy hydrocarbon contaminants from the GaagSBisohen and less effective removal of such contaminants from the solvent than the more costly one.

0098U / 1935

BATH ORIGINAL

System that focuses entirely on the removal of impurities by washing with a solvent the lust for hydrocarbons with at least 3 carbon atoms contains, fractionally distilled and ethylene dichloride can be returned to the scrubber · Alternatively this ethylene dichloride medium is treated with chlorine, to cause the reaction with the heavy hydrocarbons «u, where the ethylene dichloride is then obtained and led to the Uok to the washer.

Ks was found to be in dilute, contaminated Acetylene and aoetylene / ethylene mixtures contain the hydrocarbon impurities Ethylene reacts more easily with chlorine, and the ethylene component reacts more easily the acetylene.

In the case of a dilute acetylene mixture which is practically free of ethylene, the use of molar ratios of chlorine / hydrocarbon impurities of 1x1 to 3 »1 can ensure that practically only hydrocarbon impurities which contain at least 3 carbon atoms are chlorinated. In such a process a catalyst such as Ferriohlorid, presence or absence · Preferably, temperatures can be in the order of 40 ⁰ C

0098U / 1935

BATH ORIGINAL

up to 80 ⁰ G applied and ethylene chloride or sym _o -! Eetraehloräthan ale chlorinated hydrocarbon medium used. The pressure to be used depends on the concentration of acetylene in the diluted Gemisoh. the partial pressure of acetylene from 1 to 1.3 ata, and this corresponds to a total pressure of 10 to 135 ata. The effect of a particular reaction condition can in turn be compensated for by others; the effect of the low temperatures on the chlorination reaction can be compensated for by using increased pressure and increased contact tents «

According to a further feature of the invention, in a process after the chlorination step to remove the chlorinated hydrocarbons having at least 3 carbon atoms, the purified, dilute acetylene mixture is then subjected to the action of chemicals which react with the acetylene component to form desired products «. Thus the purified, diluted acetylene Gemisoh can with hydrogen chloride in the presence of activated carbon "which is impregnated with catalysts, eg MercurlChlorid, are reacted at temperatures ranging from 10O ⁰ C to 200 ⁰ C to the valuable product vinyl chloride devoted This purified Acetylene mixture can also be mixed with acetic acid in the vapor phase in the presence of a catalyst such as zinc

BATH ORIGINAL

0098U / 1935

aoetat, to be converted to form vinyl acetate « purified or partially purified, diluted Aoetylen-Geaisoh can also be heated with hydrogen chloride and a source of oxygen in the presence of a ueacon catalyst to give trichlorethylene as the main product, wit

this in the patent specification (patent application J 29

IVb / i2o) described iet. The cleaned or partially cleaned Aoetylene mixture can also be used with an amount of chlorine in eym.-Tetraohloräthan in the presence of PerriChlorid Catalyst at a temperature of at least 70 C and to sum boiling point of sym.-tetrachloroethane to be implemented to convert the acetylene into sym.-Tetraohloräthan and all chlorinating heavy hydrocarbon impurities. According to a modification of the latter procedure, the original diluted, contaminated aoetylene qemisoh in eym.-Tetraohloräthan, which contains this catalyst, treated at the temperatures mentioned with an amount of chlorine, to convert the acetylene into eym.-Tetraohloräthan and the sohweren hydrocarbon impurities chlorinate. With this modified procedure, the chlorination of the undesirable hydrocarbon impurities can and the conversion of acetylene to sym.-tetraohlorethane can be effected in a single step. Ba the heavy hydrocarbon impurities themselves la original dilute aoetylene mixture only in small quantities.

0098U / 1935

are, relatively minor amounts of chlorine are required to chlorinate the impurities in comparison EU the amount iot required in order to convert acetylene in sym-tetrachloroethane zn.

The present invention is particularly valuable in theirs Use on dilute acetylene / ethylene mixtures containing the heavy hydrocarbons are contaminated.

With the latter mixtures it is possible to use the heavy ones Chlorinating hydrocarbon impurities in said chlorinated hydrocarbon medium, and the ethylene component only in a lesser amount of wetland, e.B, 107C the Ethylene component, to be converted into Xthylenediohlorid! the The ethylene component can then be used in a following Can be chlorinated. Alternatively, the contaminated ethylene / ethylene mixture in a single stage with a Amount of chlorine treated to chlorinate the small amount of heavy hydrocarbons, and the ethylene to convert practically all of it into ethylene dichloride Other reaction conditions, such as pressure, contact time, presence or absence of catalyst, can also apply be varied · So the increase in pressure and contact time and the presence of catalysts all lead with increased conversion of the ethylene component. Bas preferred Solvent is in turn Äthylendiohlorld, the

0098U / 1935

preferred catalyst is ferric chloride, and its ancestor is carried out beforehand under overpressure. Dae remaining Acetylene can be converted into chemicals that consume acetylene in the manner mentioned above, in order to e.g. B. vinyl chloride, vinyl acetate and triohlorethylene iu give The ethylene dichloride product can be pyrolyzed to Form vinyl chloride and hydrogen chloride, the latter being utilized in the reaction with acetylene.

In the event of any reactions involving a contaminated, diluted Aoetylen / Ethylen-Geaieohee can the latter β like the contaminated Aoetylen-Qemleoh with a leaching agent be accustomed to some of the old coal water pollution to remove·

When diluted Aoetylen / Äthylen-Gemieohe with these heavy hydrocarbons are contaminated, chlorinated are used to convert the heavier hydrocarbons, while acetylene and ethylene are only used to a lesser extent can be chlorinated, in turn, the purified acetylene / ethylene mixture can first be exposed to other chemicals ale chlorine, which with the acetylene component, as before described, react, implemented and then the lagging one Ethylene component with chlorine with the formation of ethylenedi Chloride are reacted. The purified aoetylene /

0098U / 1935

Ethylene mixture with hydrogen chloride in the presence of activated carbon, which is impregnated with catalysts, e.g. mercuric chloride is to be reacted to form vinyl chloride, and the purified ethylene can then be mixed with chlorine to form ethylene dichloride implemented.

In another operation according to the invention is as "dilute / ethylene mixture treated contaminated acetylene in sym ₀ -Tetrachloräthan in the presence of a catalyst, for example Perrichlorid, at temperatures in the order of 40 ⁰ G 70 ⁰ C with chlorine to the heavy hydrocarbons in a single step "and chlorinate and acetylene and ethylene component in sym ^ Tetrachloräfchan and ethylene dichloride to transfer ₀

The following example explains the invention without relating it restrict ο

example

The experiments were performed _s ethylene and nitrogen with a gaseous mixture of acetylene containing 600 ppm of methyl acetylene, allene, vinyl acetylene and butadiene containing respectively as hard · hydrocarbon impurities in the table MA ·, All., VA and Β.Ώ . to be named.

009814/1935

BATH ORIGINAL

.14-156883fr

The reaction vessel comprised a glass column 2.5 cm in diameter and 150 cm in length, which was packed with 0.6 µm glass pods was. The column was filled with 500 com Äthylendiohlorid (A.D.C) or Bym.-Tetrachloräthan (s.Tet.) And bsi held at the desired temperature. The liquid medium contained 0.1 £ w / w

The gas mixture was introduced into the bottom of the column and chlorine was injected into the column at a distance of 5 µm above the inlet for the gas mixture. The flow rate was 3 L / h CgH ₂ , 7 L / h C ₂ H _4, and 75 IA * 2 ^{# 1} ^ * chlorine flow rate was adjusted to obtain the conversion shown in the table. The duration of the experiments was about 7 hours.

The exhaust gas was passed through a water washer and a washer passed with aqueous NaOH. The effectiveness of the reaction was determined by gas / liquid chromatography analysis Inlet gas and exhaust gas (of the scrubbed gas stream) are determined. The ethylene was essentially converted into ethylene dichloride. The results are given in the following table!

0098U / 1935

BATH ORIGINAL

Ver ·· Χ ·· Ρ · Reactlone catalysis conversion # to conversion i » to Ir. C medium eat or ethylene acetylene impurities

H.A. All. V.A. B.D

' 1 40 A.D.C. p.ci ₃ 95 2 40 A.D.Cc 80 3 80 e.Tet. PeCl ₃ 80 4th 80 e.Tet. PeCl ₃ 70

> 3

not> 98
be
Right 95 ^ 98 67 90 92 95 75 95 90 95 75> 98 90 > 98

Bin further Vereuoh a ·· was diluted with a nloht-katalyeierten reaction, contaminated ethylene Gemlsohee carried out with chlorine in XthylendlChlorid at 40 ⁰ C. It was observed that similar conversions of the impurities were obtained with a 40% conversion of the ethylene.

0098U / 1935

Claims (1)

Claims 1. Process but at least partial removal of heavy hydrocarbon impurities containing at least 3 carbon atoms in dilute aoetylene or aoetylene / Ethylene mixtures, characterized in that these mixtures with chlorine in a liquid, chlorinated hydrocarbon medium, which is inert to chlorine in the weeentliohen under conditions of liquid phase chlorination, treated with the so formed chlorinated hydrocarbons with at least 3 carbon atoms per cent in the chlorinated hydrocarbon medium To be kept in the office. 2c method naoh claim 1, daduroh gekenneelohnet, deJ as a liquid, chlorinated hydrocarbon medium, carbon tetra-carbon, sym.-tetrachloroethane, 1,2-di-chloroethane or a Chlorinated, aromatic hydrocarbon, such as TrichlorbenBOl, is used. 3 · Method according to claim 1 or 2, because known β is worthwhile, that the chlorination stage in the absence of a catalyst " is carried out. 4. Method according to claim 1 or 2, characterized in that da0 the chlorination stage in the presence of a metal chloride catalyst is carried out. 0098U / 1935 5 »Method according to claim 4» characterized by »ftafi ferric chloride is used as the metal chloride catalyst o 6, method according to any one of the preceding claims, characterized characterized that 1 to 3 Hol of chlorine per Hol of heavy Hydrocarbon contaminants are used. 7ο Method according to one of the preceding claims, thereby characterized that the diluted, contaminated acetylene or aoetylene / ethylene mixture with a solvent to remove hydrocarbon contaminants from a rope is washed with at least 3 carbon atoms o 8o method naoh one of the preceding claims, daduroh characterized in that after removal of the hydrocarbon impurities from a dilute acetylene mixture, the purified Acetylene mixture subjected to the action of chemicals reacting with the acetylene component., 9ο method according to claim 8, characterized in that that the purified, dilute acetylene mixture with hydrogen chloride in the presence of activated carbon with a catalyst is impregnated, is reacted with the formation of vinyl chloride. 0098U / 1935 10 · Process according to one of the preceding claims ·, I ₉ 2.5 »7 and 8, characterized in that the · purified · or partially purified, dilute acetylene mixture in sym temperature of at least ⁰ · 70 C and is implemented to sum boiling point of sym-tetrachloroethane with a quantity of chlorine, to chlorinate u «any sohwere Eohlenwaeseretoff impurities and there · acetylene in sym.-eu Xetraohloräthan about drove · 11. The method naoh claim 1, 2, 5 and 8, characterized in that the dilute, contaminated Aoetylen-Gemieoh in eynu-tetrachloroethane in the presence of Perriohlorid as a catalyst at a temperature of at least 70 ⁰ C and to sub boiling point of sym.- Tetrachloroethane is reacted with an amount of chlorine to chlorinate all heavy Kohlenwaeeeratoff impurities and the acetylene is converted into eym.-Tetraohlorathan su. 12. The method according to claims 1 to 5 and 7, characterized in that that a dilute, contaminated aoetylene / Xthylene Gemisoh treated with chlorine to chlorinate the heavy hydrocarbon impurities au and the ethylene component to be transferred to Xthylendiohlorld only to a lesser extent, dl the rest of the ethylene component in a subsequent stage Äthylendiohlorid ohlorlert and then the reatlioh aoetylen- 0098U / 1935 INSPECTED Component subject to the action of chemicals associated with the aoetylene component react. 13e A method according to claim 1 to 5 and 7, characterized in _t that is treated a diluted, polluted acetylene / Xthylen-aemlsoh with chlorine and chlorinated heavy hydrocarbon impurities in a single step and praktieoh the geeamte ethylene component in ethylene dichloride convicted and aneohließend subjects the remaining acetylene component to the action of chemicals which react with the acetylene component. 14 · Method according to claims 1 to 5 and 7, characterized by no. that a dilute, contaminated acetylene / ethylene Gemisoh with chlorine for chlorination of the heavy hydrocarbons treated, while the Aoetylen / Xthylen-Gemisoh is chlorinated only to a lesser extent, then the purified one Aoetylen / Xthylen-QemlBoh the action of other chemicals al · subjects chlorine, which react with the aoetylene component, and then reacting the remaining ethylene component with chlorine to form xethylene dichloride. 15 · Method according to claims 12, 13 and 14, characterized in that that the acetylene component is treated with hydrogen chloride in the presence of activated carbon, which is impregnated with a catalyst reacts to form vinyl chloride, 0098U / 1935 16 «A method NaOH to claim 1, 2, 4, 5 and 7, daduroh in that a diluted, verunreinlgtee Gemisoh of Aoetylen and ethylene In eym.-Tetraohloräthan In the presence of catalyst at a elnee Tenperatur In Gtrufienordnung of 4O ⁰ C to 70 ⁰ O treated with chlorine and ohloriert the eohweren hydrocarbons in a einsigen stage and transferred to the Aoetylen- and ethylene components in sym.-Tetraohiorathan or Äthylendiohlorld. 17 · Organic compounds! manufactured according to a process according to one of the preceding claims. PATINTANWXLTI OB-INO H. FINCKE. 0IM - ING. H. SOHt DIPt-ING. 0098U / 1935