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àJEuropâisches European Patent Office (jj) Publication number: 0 007 064

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@ EUROPEAN PATENT SPECIFICATION

@ Dateof publication of patent spécification: 19.01.83 @ Int. Cl.3: C 07 C 17/38, C 07 C 1 9/045 @ Application number: 79102263.5

@ Date offiling: 04.07.79

(54) Purification of ethylene dichloride.

(30) Priority: 07.07.78 US 922717 @ Proprietor: PPG INDUSTRIES, INC. One Gateway Center Pittsburgh Pennsylvania 1 5222 (US) (43) Date of publication of application: 23.01.80 Bulletin 80/2 @ Inventor: Walker, Henry Rideout 922 Wilshire (45) Publication of the grant of the patent: Corpus Christi, Texas 7841 1 (US) 19.01.83 Bulletin 83/3 (74) Representative: Hann, Michael, Dr. (84) Designated Contracting States: Marburger Strasse 38 BE DE FR GB IT NL SE D-6300 Giessen (DE)

(56) References cited: DE - B - 1 468 480 DE-B - 1 793 051 DE - B - 2 603 477 US -A- 3 691 239 US -A- 3 996 300 US-A-4020117

Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1 ) European patent convention). Courier Press, Leamington Spa, England. Background of the invention of said product is reduced by contacting it with Ethylene dichloride (1,2-dichloroethane) is alumina, said process being characterized in typically produced by catalytic vapor phase oxy- that the chloral containing reaction product is chlorination of ethylene wherein a gaseous contacted with alumina by passing a gaseous mixture of ethylene, hydrogen chloride, and stream of said reaction product through a fixed oxygen are reacted in the presence of a Deacon- bed of alumina at a temperature of from 200°C type catalyst, e.g., copper halide catalyst. The to 300°C, said alumina having a Brunauer, oxychlorination product gas stream is Emmet and Teller surface area of from 30 to condensed to form organic and aqueous acidic 600 square meters per gram, the volume of said liquid phases. The organic phase containing alumina bed being from 10 to 60 percent of the crude ethylene dichloride is further purified by, volume of the oxychlorination catalyst, con- for example, distillation and the aqueous acidic densing said stream and recovering ethylene di- phase is discharged to waste. chloride from te condensation product. Although satisfactorily high yields of ethylene The determination of the Brunauer, Emmet dichloride may be obtained by the vapor phase and Teller ("BET") surface is described in J. Am. oxychlorination of ethylene, both the organic Chem. Soc. Vol. 60, pp. 30 et seq. (1938). A and aqueous phases typically contain preferred range of the BET surface area of objectionable amounts of chloral, i.e., from alumina is from 100 to 300 square meters per about 0.2 to 0.5 percent by weight, in the gram. The volume of the alumina is preferably organic phase and in excess of 2 percent by from 10 percent to 30 percent of the volume of weight in the aqueous phase. the oxychlorination catalyst. Since chloral is classified as a pollutant, it A higher relative volume of alumina to oxy- must be substantially removed from the chlorination catalyst is used when the alumina aqueous phase prior to discharge to waste and has a low BET surface area and conversely a also must be removed from the organic phase in lower relative volume of alumina to oxy- order to produce high purity ethylene dichloride. chlorination catalyst is used when the alumina One means of removing chloral from the has a high BET surface area. condensed oxychlorinated product stream is Care should be taken that neither too much disclosed in U.S. Patent No. 3,378,597 wherein nor too little alumina be used. The use of too aqueous sodium hydroxide is used to much alumina will result in an overly long decompose chloral to chloroform and sodium contact time with the oxychlorination product formate. However, both chloroform and sodium stream which tends to decompose not only formate also pose a waste disposal problem and chloral but also ethylene dichloride product. require additional treatment, e.g., bioxidation or Conversely with the use of too little alumina the like, before being discharged to a receiving there will be insufficient contact time with the stream. oxychlorination product stream resulting in DE-B2-1 793 051 shows a process for incomplete decomposition of chloral. recovering the reaction mixtures obtained in the The optimum volume ratio of alumina having preparation of ethylene dichloride by vapor a particular BET surface area to oxychlorination phase oxychlorination of ethylene. The reaction catalyst for a given system may, however, be product is first condensed to separate ethylene readily determined without excessive experi- dichloride and water in the liquid phase. The mentation simply by varying the volume of remaining gas stream which comprises alumina to oxychlorination catalyst within the excessive ethylene is reacted with chlorine in above specified limits bearing in mind that the the presence of alumina in order to form higher the BET surface area of the alumina, the ethylene dichloride. In this process chloral is not lower the relative volume of alumina based on removed from the major part of the reaction the volume of oxychlorination catalyst. product which is condensed immediately after The temperature of the alumina bed is main- the oxychlorination. tained at from 200°C to 300°C, preferably from It is desirable, therefore, to provide means for 240°C to 260°C, and, in order to obtain satis- removing chloral prior to condensing the factory decomposition of chloral, the oxy- gaseous oxychlorination product stream which chlorination product stream should contain from would preclude further treatment of any phase 1 to 5 percent by volume oxygen. to remove chloral therefrom. In a typical practice of the invention, In accordance with this invention a process ethylene, hydrogen chloride, and oxygen gases has been found of preparing ethylene dichloride are fed in known fashion to a fluid reactor con- by vapor phase oxychlorination of ethylene taining an oxychlorination catalyst at a rate suf- wherein a gaseous mixture of ethylene, ficient to maintain the catalyst bed in a fluidized hydrogen chloride, and oxygen are contacted at condition without significant entrainment of an elevated temperature with an .oxy- catalyst particles in the product gas stream and chlorination catalyst to produce a chloral con- to intimately contact the gaseous reactants with taining reaction product and the chloral content the fluidized catalyst. Of course, the vapor phase oxychlorination of ethylene to ethylene di- weight percent potassium, and 9.0 weight chloride may be conducted using a fixed or percent chloride; had a BET surface area of static catalyst bed rather than a fluidized about 37 square meters per gram; and had a catalyst. Particle size of the oxychlorination bulk density of about 39.4 pounds per cubic catalyst is not particularly critical, although for foot. fluid bed operation catalyst particle size is typically in the range of 0.076 to 0.500 mm, preferably between 0.152 to 0.388 mm. The Example 2 reaction may be conducted over a wide range of A tube from a corrosion resistant alloy (79 temperature, for example, between 150°C to percent Ni, 14 percent Cr, 7 percent Fe) 1,5 m 500°C, preferably between 250°C and 350°C. in height and 5 cms in diameter was employed Contact time between the gaseous reactants is as a fluid bed oxychlorination reactor. The typically not more than about 30 seconds and reactor was enclosed in a 6 inch diameter steel usually about 10 seconds. Depending on jacket forming an annular heat exchange reaction conditions and catalyst selection, system. "Dow Therm E" (a diphenyl-diphenyl- conversion of ethylene to ethylene dichloride oxide eutectic sold by The Dow Chemical Co.) usually ranges from about 70 percent to sub- was circulated in the annular space formed stantially quantitative and ethylene dichloride between the jacket and the outer surface of the crude having an ethylene dichloride content of reactor to control the fluid bed temperature. from 97 percent to 99 percent may be obtained. A 1 liter capacity glass secondary reactor The product gas stream from the oxy- was connected to the oxychlorination reactor chlorination reactor is passed through a vent with a glass-crossover. Both the secondary secondary reactor containing a fixed or static reactor and the crossover were wrapped with bed of particulate alumina maintained at a tem- insulation and externally controlled heating perature of from 200°C to 300°C, the volume tape. The outlet of the secondary reactor was of alumina being proportioned to the volume of connected to a condenser system. oxychlorination catalyst in the fluid reactor as The oxychlorination reactor was charged to a described hereinabove. depth of 63.5 cms with the catalyst prepared in It is, of course, to be understood that rather Example 1 and the secondary reactor was than employing a single alumina containing charged with alumina. Two types of commer- reactor, two or more such reactors connected in cially available alumina were tested, i.e., series may be employed. Aluminum Company of America F-1 grade The gaseous stream, after passage through alumina screened to 0.388 mm (+40 mesh) the alumina bed, is condensed in known fashion having a BET surface area of 300 ml/g (Type A) to form organic and aqueous liquid phases. The and Norton Co. No. SA-3232 6.35 mms organic phase containing ethylene dichloride alumina spheres having a surface area of 30 having a reduced chloral content is further m2/g (Type N). purified by, for example, distillation, and the A gaseous mixture of ethylene, hydrogen aqueous phase also having a reduced chloral chloride, and oxygen in a molar ratio content may be discharged to waste treatment of ethylene:hydrogen chloride:oxygen of to neutralize hydrochloric acid or depending on 1.0:1.5:0.45 was fed to the bottom of the oxy- the hydrochloric acid content, the same may be chlorination reactor and up through the catalyst recovered, if economical. bed at a rate sufficient to maintain the same in a The effectiveness of alumina in removing fluidized condition. Reaction temperature was chloral from a gaseous product stream controlled at 295°C and contact time of the produced by catalytic oxychlorination of gaseous reaction mixture with the fluidized ethylene is illustrated but is not intended to be catalyst was about 10 seconds. limited by the following example. The product gas stream from the oxy- chlorination reactor was fed downwardly through the alumina bed in the secondary Example 1 reactor and the effluent gas from the secondary Preparation of oxychlorination catalyst reactor was condensed and the organic and About 2,233 grams of (30x60 mesh U.S. aqueous phases were submitted for analysis. Sieve) attapulgite clay with a particle size of A series of runs were made using various 0.251 to 0.500 mm were thoroughly mixed volume ratios of Types A and N alumina to oxy- with about 2,250 milliliters of an aqueous chlorination catalyst and at various secondary solution containing about 645 grams cupric reactor temperatures and compared with a chloride (CuCl,. 2H,O) and about 258 grams control run wherein the oxychlorination product potassium chloride (KCI). The resultant slurry, gas stream was not passed through the alumina having a mud-like consistency, was dried at bed. In all of the runs, the ethylene dichloride 160°C for about 48 hours in a forced draft content of the crude organic phase averaged. oven. The dried cake was broken up and ground about 97.72 weight percent with a range of to a particle size of 0.076 to 0.220 mm (-70 from 96.63 to 98.53 percent by weight. The +200 mesh). The catalyst thus prepared results and conditions of these runs are sum- contained about 7.9 weight percent copper, 4.0 marized in Table I. 1. A process of preparing ethylene dichloride 1. Verfahren zur Herstellung von Ethylendi- by vapor phase oxychlorination of ethylene chlorid durch Dampfphasen-Oxychlorierung von wherein a gaseous mixture of ethylene, Ethylen, wobei eine gasförmige Mischung von hydrogen chloride, and oxygen are contacted at Ethylen, Chlorwasserstoff und Sauerstoff bei an elevated temperature with an oxy- einer erhöhten Temperatur mit einem Oxy- chlorination catalyst to produce a chloral con- chlorierungskatalysator in Berührung gebracht taining reaction product and the chloral content werden, um ein Chloral enthaltendes Reaktions- of said product is reduced by contacting it with produkt herzustellen und der Chloralgehalt dieses alumina, characterized in that the chloral Produkts durch Berührung mit Aluminiumoxid containing reaction product is contacted with herabgesetzt wird, dadurch gekennzeichnet, alumina by passing a gaseous stream of said daß das chloralhaltige Reaktionsprodukt mit reaction product through a fixed bed of alumina Aluminiumoxid in Berührung gebracht wird, at a temperature of from 200°C to 300°C, said indem man einen gasförmigen Strom dieses alumina having a Brunauer, Emmet and Teller Reaktionsproduktes durch ein Aluminiumoxid- surface area of from 30 to 600 square meters Festbett bei einer Temperature von 200°C- per gram, the volume of said alumina bed being 300°C hindurchleitet, wobei das Aluminium- from 10 to 60 percent of the volume of the oxy- oxid eine Brunnauer-, Emmet- und Teller-Ober- chlorination catalyst, condensing said stream fläche von 30 bis 600 m2 pro Gramm hat, das and recovering ethylene dichloride from the Volumen des Aluminiumoxidbettes 10 bis 60% condensation product. des Volumens des Oxychlorierungskatalysators 2. A process according to claim 1 wherein ausmacht, den genannten Strom kondensiert the stream of the gaseous reaction product is und Ethylendichlorid aus dem Kondensations- contacted with the alumina bed at a tem- produkt isoliert. perature of from 240°C to 260°C. 2. Verfahren nach Anspruch 1, dadurch 3. A process according to claim 1 wherein gekennzeichnet, daß der Strom des gas- the alumina has a Brunauer, Emmet and Teller förmigen Reaktionsproduktes mit dem Alu- surface area from 100 to 300 square meters per miniumoxidbett bei einer Temperatur von gram. z40°C bis 260°C in Berührung gebracht wird. 4. A process according to claim 1 wherein 3. Verfahren nach Anspruch 1, dadurch the volume of the alumina bed is from 10 gekennzeichnet, daß das Aluminiumoxid eine percent to 30 percent of the volume of oxy- Brunnauer-, Emmet- und Teller-Oberfläche von chlorination catalyst. 100 bis 300 m2 pro Gramm hat. 4. Verfahren nach Anspruch 1, dadurch comprise entre 200 et 300°C, cette alumine gekennzeichnet, daß das Volumen des possédant une surface active selon Brunauer, Aluminiumoxidbettes 10 bis 30% des Volumens Emmett et Teller entre 30 et 600 m2/g et le des Oxychlorierungskatalysators ausmacht. volume du lit d'alumine constituant entre 10 et 60% du volume du catalyseur d'oxy- chloruration, le courant gazeux étant ensuite condensé et le dichlorure d'éthylène extrait du 1. Procédé de préparation du dichlorure produit condensé. d'éthylène par oxychloruration de l'éthylène en 2. Procédé suivant la revendication 1, carac- phase gazeuse, consistant à mettre en contact térisé en ce que le contact du courant du produit un mélange gazeux d'éthylène, de chlorure réactionnel gazeux avec le lit d'alumine est d'hydrogène et d'oxygène à une température réalisé à une température entre 240 et 260°C. élevée avec un catalyseur d'oxychloruration, 3. Procédé suivant la revendication 1, carac- conduisant à l'obtention d'un produit réaction- térisé en ce que la surface active selon nel contenant du chloral, la teneur en chloral Brunauer, Emmett et Teller de l'alumine est dudit produit étant ensuite réduite par un traite- comprise entre 100 et 300 m/g. ment à l'alumine, caractérisé en ce que le 4. Procédé suivant la revendication 1, carac- produit réactionnel renfermant du chloral est térisé en ce que le volume du lit d'alumine con- mis en contact avec l'alumine par le passage stitue entre 10 et 30% du volume du catalyseur d'un courant gazeux dudit produit réactionnel à d'oxychloruration. travers un lit fixe d'alumine à une température