Chlorination of ethane

CCls CHO. A colourless oily liquid with a pungent odour b.p. 98°C. Manut actured by the action of chlorine on ethanol it is also made by the chlorination of ethanal. When allowed to stand, it changes slowly to a white solid. Addition compounds are formed with water see chloral hydrate), ammonia, sodium hydrogen sulphite, alcohols, and some amines and amides. Oxidized by nitric acid to tri-chloroethanoic acid. Decomposed by alkalis to chloroform and a methanoate a convenient method of obtaining pure CHCI3. It is used for the manufacture of DDT. It is also used as a hypnotic. 

Like the chlorination of methane chlorination of ethane is carried out on an industrial scale as a high temperature gas phase reaction... 

Chlorination of ethane yields in addition to ethyl chloride a mixture of two isomeric dichlorides What are the structures of these two dichlorides ... 

Methane, chlorine, and recycled chloromethanes are fed to a tubular reactor at a reactor temperature of 490—530°C to yield all four chlorinated methane derivatives (14). Similarly, chlorination of ethane produces ethyl chloride and higher chlorinated ethanes. The process is employed commercially to produce l,l,l-trichloroethane. l,l,l-Trichloroethane is also produced via chlorination of 1,1-dichloroethane with l,l,2-trichloroethane as a coproduct (15). Hexachlorocyclopentadiene is formed by a complex series of chlorination, cyclization, and dechlorination reactions. First, substitutive chlorination of pentanes is carried out by either photochemical or thermal methods to give a product with 6—7 atoms of chlorine per mole of pentane. The polychloropentane product mixed with excess chlorine is then passed through a porous bed of Fuller s earth or silica at 350—500°C to give hexachlorocyclopentadiene. Cyclopentadiene is another possible feedstock for the production of hexachlorocyclopentadiene. 

Three industrial processes have been used for the production of ethyl chloride hydrochlorination of ethylene, reaction of hydrochloric acid with ethanol, and chlorination of ethane. Hydrochlorination of ethylene is used to manufacture most of the ethyl chloride produced in the United States. Because of its prohibitive cost, the ethanol route to ethyl chloride has not been used commercially in the United States since about 1972. Thermal chlorination of ethane has the disadvantage of producing undesired by-products, and has not been used commercially since about 1975. 

Chlorination of Ethane. Ethane [74-84-0] maybe chlorinated thermally, catalyticaHy, photochemicaHy, or electrolyticaHy. Monochlorination is favored because ethyl chloride chlorinates at about one-fourth of the rate at which it is itself produced from ethane. 

Thermal chlorination of ethane is generally carried out at 250—500°C. At ca 400°C, a free-radical chain reaction takes place ... 

Dichloroethane is also one of the iatermediate products of high temperature thermal chlorination of ethane or ethyl chloride. In ethane chlorination, the reaction proceeds through ethyl chloride as an iatermediate (12). 1,1-Dichloroethane itself is usually an iatermediate ia the productioa of viayl chloride and of 1,1,1-tfichloroethane by thermal chlorination or photochlofination (13). 

A process of minor importance utili2es a continuous noncatalytic chlorination of ethane which produces 1,1,1-trichloroethane and a number of other products, depending on the reaction conditions. 

The principal U.S. producers of 1,1,1-trichloroethane include The Dow Chemical Company, PPG Industries Inc., and Vulcan Materials Co. Several European and Japanese companies also produce large amounts aimually. Over 70% of the production is based on the vinyl chloride-1,1-dichloroethane process, 20% on the 1,1-dichloroethylene process, and about 10% on the direct chlorination of ethane. 

Thermal capacity rate, 13 253 Thermal-chemical decomposition of ozone, 17 770-773 Thermal chlorination, of ethane, 10 588 Thermal coefficient of expansion (TCE),... 

Looking further ahead, the commercialisation of the EVC process for the direct chlorination of ethane with its expected cost savings would challenge the cost structures of conventional plants leading to VCM capacity being built in very low-cost regions for both ethane and power. Obviously where the chlorine is made will... 

In the future it might be possible to see the gas diffusion technology generating chlorine with energy consumption at 1500 kWh. The chlorine will be used in the direct chlorination of ethane to feed the vinyl chain. Side streams of HC1 will be used in oxychlorination where ethylene is available and this will use up by-product acid from isocyanates. Site integration will increase to benefit from economies of scale and optimise hydrogen chloride production. 

Alkanes. The chlorination of ethane known to produce more 1,1-dichloroethane than 1,2-dichloroethane is explained by the so-called vicinal effect.115 One study revealed285 that this observation may be explained by the precursor 1,2-dichloroethane radical (the 11 2-chloroethyl radical) thermally dissociating into ethylene and a chlorine atom [Eq. (10.54)]. Indeed, this radical is the major source of ethylene under the conditions studied. At temperatures above 300°C, the dissociation dominates over the chlorination reaction [Eq. (10.55)], resulting in a high rate of ethylene formation with little 1,2-dichloroethane ... 

Chlorination of ethane yields, in addition to ethyl chloride, a... 

The entropy change AS0 for the formation of chloroethane by chlorination of ethane is +0.5 e.u., and for the formation of chloroethane by combination of hydrogen chloride with ethene AS0 is —31 e.u. Explain. 

Finally, ethylchloride can be obtained by a combined technique from a mixture of ethane and ethylene. The process is based on combined subsequent reactions of substitutuve chlorination of ethane and hydrochlorination of ethylene with hydrogen chloride obtained from the first reaction ... 

A number of important large-volume petrochemicals are obtained through the chlorination of ethane and ethylene. The laigest-volume... 

A much smaller amount is produced by the thermal chlorination of ethane. This direct chlorination may be run in conjunction with another process, such as oxychlorination, which can use the byproduct HCI as feed. 

Trichloroethane can be produced by three methods by chlorination of 1,1-dichloroethane, from 1,1,2-trichloroethane via 1,1 -dichloroethylene, and by direct chlorination of ethane. In the United States the first route produces about 70 percent. In this process the EDC feedstock is rearranged to... 

Dichloroethane is produced commercially through the reaction of hydrogen chloride and vinyl chloride at 20°-55°C in the presence of an aluminum, ferric, or zinc chloride catalyst (Grayson 1978). Other production methods include the direct chlorination of ethane, the reaction of PCI s with acetaldehyde as a by-product during the manufacture of chloral (Browning 1965), and as intermediate in the production of vinyl chloride and 1,1,1-trichloroethane by photochlorination (Windholz 1983). 

The chlorination of ethane illustrates the three distinct parts of radical halogenation (Mechanism 15.1) ... 

Energy changes in the propagation steps during the chlorination of ethane... 

Small amounts of ethylene dichloride (b.p. 83.5°C) are also recovered as a by-product from the direct chlorination of ethane to ethyl chloride (chlor-oethane). 

When a hydrocarbon has more than one C atom, its reaction with CI2 is more complex. The first step in the chlorination of ethane gives the product that contains one Cl atom per molecule. 

The most common method for industrial preparation of 1,1,1-trichloroethane is the reaction of hydrochloric acid with vinyl chloride (obtained from 1,2-dichloroethane) to obtain 1,1-dichloroethane, followed by either thermal or photochemical chlorination. Other methods include the catalyzed addition of hydrogen chloride to 1.1-dichloroethylene, and the direct chlorination of ethane itself, followed by separation from the other products produced (Archer 1979). Commercial grades of... 

Several papers discussing industrial processes for the manufacture of individual chlorinated paraffins may be of interest. Hirschkind (42) gave flow diagrams and an outline for the continuous process for the chlorination of methane in which all the chlorinated methanes are produced. Wilson and Howland (78) discuss the effect of different variables on methane chlorination. Detailed drawings of equipment and an outline of the process for the chlorination of ethane in both the liquid and the gaseous phase are given by Sergeys (67). 

Chlorination of Ethane—a Gas Phase Type Plant Proposed for Heydebreck and a Liquid-Phase Pilot Plant at Oppau. 

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