Chlorine reaction with ethylene

A recent example of a product that is demanding in terms of process chemistry is a new herbicide from BASF. The seven-step synthesis requires bromination, chlorination, carbonylation, oxydation (with H2O2), hydrogenation, and a reaction with ethylene. As no fine-chemical manufacturer was in a position to offer the whole range of process technologies, the manufacture will be split between two fine-chemical companies. 

The liquid phase processes resembled Wacker-Hoechst s acetaldehyde process, i.e., acetic acid solutions of PdCl2 and CuCl2 are used as catalysts. The water produced from the oxidation of Cu(I) to Cu(II) (Figure 27) forms acetaldehyde in a secondary reaction with ethylene. The ratio of acetaldehyde to vinyl acetate can be regulated by changing the operating conditions. The reaction takes place at 110-130°C and 30-40 bar. The vinyl acetate selectivity reaches 93% (based on acetic acid). The net selectivity to acetaldehyde and vinyl acetate is about 83% (based on ethylene), the by-products being CO2, formic acid, oxalic acid, butene and chlorinated compounds. The reaction solution is very corrosive, so that titanium must be used for many plant components. After a few years of operation, in 1969-1970 both ICI and Celanese shut down their plants due to corrosion and economic problems. 

It may be concluded that primary alkyl chlorides undergo peroxide-induced, hydrogen chloride-promoted, alkylation with ethylene to yield products formed by alkylation at a tertiary carbon atom, at a penultimate secondary carbon atom, or at a primary carbon atom holding a chlorine atom. In the absence of hydrochloric acid, n-butyl chloride underwent little peroxide-induced reaction with ethylene presumably because hydrogen chloride is necessary for propagating the reaction chain via abstraction of hydrogen from the hydrogen chloride to produce the ethylated product and a chlorine atom which maintains the chain by abstraction from the alkyl chloride. 

O2) or (CIF3 + water). Potentially explosive polymerization reaction with ethylene. Incompatible with 1,1-dichloroethylene oxygen. When heated to decomposition it emits toxic fumes of F and CL. See also CHLORINATED HYDROCARBONS, ALIPHATIC and FLUORIDES. 

The process is fed with three streams ethane, ethylene, and chlorine. The ethane and ethylene streams have the same molar flow rate, and the ratio of chlorine to ethane plus ethylene is 1.5. The ethane/ethylene stream also contains 1.5 percent acetylene and carbon dioxide. (For this problem, just use 1.5 percent carbon dioxide.) The feed streams are mixed with an ethylene recycle stream and go to the first reactor (chlorination reactor) where the ethane reacts with chlorine with a 95 percent conversion per pass. The product stream is cooled and ethyl chloride is condensed and separated. Assume that all the ethane and ethyl chloride go out in the condensate stream. The gases go to another reactor (hydrochlorination reactor) where the reaction with ethylene takes place with a 50 percent conversion per pass. The product stream is cooled to condense the ethyl chloride, and the gases (predominately ethylene and chlorine) are recycled. A purge or bleed stream takes off a fraction of the recycle stream (use 1 percent). Complete the mass balance for this process. 

From Ethylene. This process utilizes an oxychlorination reaction with ethylene and chlorine as feedstocks. In the process, three distinct reactions can be considered to be taking place ... 

Russel [142] developed a method based on the conversion of chlorine, bromine and iodine ions into the corresponding halogenated ethanols by reaction with ethylene oxide. Belcher et al. [143] offer a method for determining trace amounts of chloride ions, based on reaction with mercury phenylnitrate to give phenylmercury chloride, which is chromatographed with flame-ionization detection. 

Potential energy surface for the chlorine atom reaction with ethylene A theoretical... 

The vapor-pheise photochemical reaction of chlorine dioxide with ethylene was observed by Furst (65) to give chloroacetic acid. Leopold and Mutton (137) discovered that the reaction between triolein and chlorine dioxide is accelerated by light cind gives a mixture of products, containing carbonyl, hydroj l, euid epoxide groups, as well as chlorine. CSilorine dioxide oxidations carried out by Lindgren and co-workers on cyclohexene (143) and methyl oleate (142) in the cib-sence of special illumination showed only a little... 

Table VII-C-2. Rate coefficients (k, cm molecule" s" ) for reaction of chlorine atoms with ethylene glycol diformate [HC(0)0CH2CH20C(0)H]...

The reaction of chlorine atoms with ethylene glycol diformate has been the subject of a relative rate study by Maurer et al. (1999) at 298 K. The results from Maurer et al. (1999) in table VII-C-2 give (C1-hHC(0)0CH2CH20C(0)H) = 3.16 x IQ- cm molecule" s with an uncertainty estimated to be 25%. Corroborative studies of this rate coefficient are warranted. 

Ponomarev, D., M.D. Hurley, and T.J. Wallington (2002), Kinetics of the reactions of fluorine and chlorine atoms with ethylene oxide (oxirane), Int. J. Chem. Kinet., 34, 122-125. 

Bromine. Slip the glass cover of a jar momentarily aside, add 2-3 ml. of bromine water, replace the cover and shake the contents of the jar vigorously. Note that the bromine is absorbed only very slowly, in marked contrast to the rapid absorption by ethylene. This slow reaction with bromine water is also in marked contrast to the action of chlorine water, which unites with acetylene with explosive violence. (Therefore do not attempt this test with chlorine or chlorine water.)... 

Chlorine reacts with saturated hydrocarbons either by substitution or by addition to form chlorinated hydrocarbons and HCl. Thus methanol or methane is chlorinated to produce CH Cl, which can be further chlorinated to form methylene chloride, chloroform, and carbon tetrachloride. Reaction of CI2 with unsaturated hydrocarbons results in the destmction of the double or triple bond. This is a very important reaction during the production of ethylene dichloride, which is an intermediate in the manufacture of vinyl chloride ... 

Chlorine can be removed by either activated carbon adsorption or by reaction with olefins such as ethylene over-activated carbon at temperatures of 30—200°C (44). Addition of Hquid high boiling paraffins can reduce the chlorine content in the HCl gas to less than 0.01% (45). 

Interaction of chlorine with methane is explosive at ambient temperature over yellow mercury oxide [1], and mixtures containing above 20 vol% of chlorine are explosive [2], Mixtures of acetylene and chlorine may explode on initiation by sunlight, other UV source, or high temperatures, sometimes very violently [3], Mixtures with ethylene explode on initiation by sunlight, etc., or over mercury, mercury oxide or silver oxide at ambient temperature, or over lead oxide at 100°C [1,4], Interaction with ethane over activated carbon at 350°C has caused explosions, but added carbon dioxide reduces the risk [5], Accidental introduction of gasoline into a cylinder of liquid chlorine caused a slow exothermic reaction which accelerated to detonation. This effect was verified [6], Injection of liquid chlorine into a naphtha-sodium hydroxide mixture (to generate hypochlorite in situ) caused a violent explosion. Several other incidents involving violent reactions of saturated hydrocarbons with chlorine were noted [7],... 

Reaction of chlorine with ethylene to produce ethylene dichloride (EDC). 

Figure 9—2 shows the plant with its three reactors. The pyrolysis furnace is in the middle. At the top of the figure, the basic feeds, to the plant are shown—ethylene, chlorine, and oxygen. Ethylene and chlorine alone are sufficient to make EDC via the route on the left. The operation, call it Reaction One like Figure 9-1 does, takes place in the vapor phase in a reactor with a fixed catalyst bed of ferric (iron) chloride at only 100—125°F. A cleanup column fractionates out the small amount of by-products that get formed, leaving an EDC stream of 96—98% purity. 

With the aid of density functional theory, the ZnCl2 acceleration of the Simmons-Smith reaction of ethylene and allyl alcohol has been investigated. A pathway involving direct Lewis acid acceleration of the leaving halogen atom (327) was found to be a more facile process than the more popular pathway involving 1,2-chlorine migration (328). 

Vinyl chloride is also produced by the direct chlorination of ethylene and the reaction of acetylene and hydrogen chloride (structure 17.29). The hydrogen chloride generated in the chlorination of ethylene can be employed in reaction with acetylene allowing a useful coupling of these two reactions (equation 17.30). 

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