Chlorination cupric chloride catalyst

The cupric chloride catalyst was promoted with potassinm chloride and supported on activated alumina. It was related to the Deacon catalyst, which was developed for chlorine production in 1887. 

Dichloroethane is produced by the vapor- (28) or Hquid-phase chlorination of ethylene. Most Hquid-phase processes use small amounts of ferric chloride as the catalyst. Other catalysts claimed in the patent Hterature include aluminum chloride, antimony pentachloride, and cupric chloride and an ammonium, alkaU, or alkaline-earth tetrachloroferrate (29). The chlorination is carried out at 40—50°C with 5% air or other free-radical inhibitors (30) added to prevent substitution chlorination of the product. Selectivities under these conditions are nearly stoichiometric to the desired product. The exothermic heat of reaction vapori2es the 1,2-dichloroethane product, which is purified by distillation. 

Dichloroethylene can be produced by direct chlorination of acetylene at 40°C. It is often produced as a by-product ia the chlorination of chloriaated compounds (2) and recycled as an iatermediate for the synthesis of more useful chloriaated ethylenes (3). 1,2-Dichloroethylene can be formed by contiauous oxychloriaation of ethylene by use of a cupric chloride—potassium chloride catalyst, as the first step ia the manufacture of vinyl chloride [75-01-4] (4). 

Oxychlorination of Ethylene or Dichloroethane. Ethylene or dichloroethane can be chlorinated to a mixture of tetrachoroethylene and trichloroethylene in the presence of oxygen and catalysts. The reaction is carried out in a fluidized-bed reactor at 425°C and 138—207 kPa (20—30 psi). The most common catalysts ate mixtures of potassium and cupric chlorides. Conversion to chlotocatbons ranges from 85—90%, with 10—15% lost as carbon monoxide and carbon dioxide (24). Temperature control is critical. Below 425°C, tetrachloroethane becomes the dominant product, 57.3 wt % of cmde product at 330°C (30). Above 480°C, excessive burning and decomposition reactions occur. Product ratios can be controlled but less readily than in the chlorination process. Reaction vessels must be constmcted of corrosion-resistant alloys. 

The catalyst is the key to this reaction and in this case is an aqueous solution of palladium chloride (PdCl2) and cupric chloride (CuCh). There is a complex, but well understood, mad scramble of ions and molecules that takes place as chlorine temporarily separates from the palladium and the copper and facilitates ethylene s reacting with oxygen. 

Raschig process (refs.9,10,11) which was essentially a regenerative route introduced prior to World War II. Chlorobenzene, obtained by the oxychlorination of benzene with an air/chlorine mixture at 200-230°C in the presence of a catalyst containing cupric chloride, ferric chloride and alumina, was hydrolysed with steam under pressure at 400-450°C over a calcium phosphate catalyst. Alternatively a copper-promoted calcium phosphate/silica catalyst has been employed. 

It has been mentioned in Section 4.1 that cupric chloride causes chlorination reactions. Thus, chlorinated aldehydes (see Eq. (9.26)) are the main by-products. Others include acetic acid and chlorinated acetic acids. Light ends are carbon dioxide, methyl, and ethyl chloride. By chlorination, oxidative, and hydrolytic reactions, oxalic acid is formed causing insoluble copper oxalate. In order to avoid an accumulation in the catalyst, it is continuously thermally decomposed by heating a small side stream in the regeneration step (reactor (i) in the one-stage, reactor (m)... 

In reaction (3.5), which oxychlorinates ethylene to produce 1,2-dichloroethane, HCl is the source of chlorine. This highly exothermic reaction achieves a 95% conversion of ethylene to dichloroethane at 250 C in the presence of cupric chloride (CUCI2) catalyst, and is an excellent candidate when the cost of HCl is low. As in reaction path 3, the dichloroethane is cracked to vinyl chloride in a pyrolysis step. This reaction path should be considered also as a solution for design alternative 3. 

Regenerative Oxidation. There is a group of regenerative processes in which HCl reacts with another material A to form an intermediate which then oxidizes back to compound A while releasing chlorine. The oxidation reaction usually requires the use of a catalyst or more severe conditions than the chlorination. The Grosvenor-Miller process is an example. This uses a fixed-bed reactor packed with ferric, rather than cupric, chloride. The course of reaction is... 

In the oxychlorination processes a mixture of ethylene, air and hydrogen chloride is passed over a catalyst of cupric chloride on an inert support at 250—315°C. Ethylene dichloride is obtained in about 90% yield and is then dehydrochlorinated (and the hydrogen chloride recycled). In some processes, which operate at higher temperatures, the ethylene dichloride is cracked in situ so that vinyl chloride is obtained in a one-stage operation. The overall oxy chlorination reaction may be represented as follows ... 

Improvements in available methodology for the oxidation of alkenes to oxirans have been described. Glycidol can be obtained in 90% yield by heating allyl alcohol with cumene hydroperoxide at 110 °C using vanadium oxychloride as catalyst. Oxidation of isoprene with peroxyformic acid gave an 80% crude yield of the vinyl oxiran, which was treated with lithium chloride and cupric chloride to give the useful synthon (15), a key intermediate in the synthesis of vitamin A from j3-ionone. This modified synthesis employs a hitherto unprecedented oxidative chlorination of a vinyl oxiran (Scheme 4). Previously, the best known method for the oxidation... 

In the late 1950s processes for producing ethylene dichloride from ethylene by oxychlorination rather than by direct chlorination were developed. In these processes ethylene is treated with a mixture of oxygen and hydrogen chloride in the presence of a catalyst consisting of a mixture of cuprous and cupric chlorides ... 

The formation of 1,2-dichloroethane from ethane and ethylene is described in patents issued to National Distillers (11) and I.C.I. (12), respectively. Englin et at. (13) report the formation of vinyl chloride from chloroalkanes using catalysts containing melts of cuprous and cupric chloride. The details of the mechanism and kinetics of many of these reactions are still unresolved. It appears, though, that copper chloride can function effectively as a catalyst for chlorination and dehydrochlorination as well as being able to participate in os chlorination reactions. 

The most economical commercial preparation is high-temperature chlorination of ethene. A useful modification of this process uses hydrogen chloride in place of chlorine. An oxidizing agent is required to raise the oxidation state of chlorine in HC1 to that of Cl2 molecular oxygen is used for this purpose along with cupric salts as catalysts. 

Catalyst, alumina, 34, 79, 35, 73 ammonium acetate, 31, 25, 27 boron tnfluonde etherate, 38, 26 copper chromite, 31, 32, 36, 12 cupric acetate monohydrate, 38, 14 cuprous oxide silver oxide, 36, 36, 37 ferric nitrate, hydrated, 31, 53 phosphoric acid, 38, 25 piperidine, 31, 35 piperidine acetate, 31, 57 Raney nickel, 36, 21, 38, 22 sulfuric acid, 34, 26 Catechol, 33, 74 Cetylmalonic acid, 34, 16 Cetylmalonic ester, 34,13 Chlorination, by sulfuryl chloride, 33, 45, 37, 8... 

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