Acetylene hydrochlorination

Cracking of preheated ethylene dichloride, at between 450 and 550°C. at 13.10 Pa absolute, followed by quenching, first indirectly for the production of steam, and then directly by the in-line injection of cold product, and then by the separation by distillation of the hydrochloric arid co-produced, which is recycled to the acetylene hydrochlorination stage. 

The hydrochlorination of olefins is a weaMy exothermic reaction with heats of reaction ranging from 4 to 21 kj/mol (1—5 kcal/mol). The hydrochlorination of acetylene is more exothermic, 184 kJ/mol (44 kcal/mol). 

Other routes to 1,1,2-trichloroethane are chlorination of acetylene in the presence of HCl (101) and chlorination of vinyl chloride at room temperatures with FeCl (102—104), hydrochlorination of cis- and /n j -l,2-dichloroethylene with FeCl catalyst (105), vapor-phase oxychlorination of... 

Halogenation and dehalogenation are catalyzed by substances that exist in more than one valence state and are able to donate and accept halogens freely. Silver and copper hahdes are used for gas-phase reactions, and ferric chloride commonly for hquid phase. Hydrochlorination (the absoration of HCl) is promoted by BiCb or SbCl3 and hydrofluorination by sodium fluoride or chromia catalysts that form fluorides under reaction conditions. Mercuric chloride promotes addition of HCl to acetylene to make vinyl chloride. Oxychlori-nation in the Stauffer process for vinyl chloride from ethylene is catalyzed by CuCL with some KCl to retard its vaporization. 

Hutchings, G.J. (1985) Vapor phase hydrochlorination of acetylene Correlation of catalytic activity of supported metal chloride catalysts. Journal of Catalysis, 96, 292-295. 

K. Shinoda, Vapour-phase hydrochlorination of acetylene over metal chlorides supported on activated carbon, Chem. Lett. 3, 219-220 (1975). 

B. Nkosi, N. J. Coville, and G. J. Hutchings, Vapour-phase hydrochlorination of acetylene with group VIII and IB metal chloride catalysts, Appl. Catal. 43(1), 33-39 (1988). 

According to Saito(Ref 7), the acetylene trimers obtained as byproducts in the prepn of CHa CH. C CH by condensation of acetylene are expl. They can be stabilized by hydrochlorination in the presence of a complex salt of CuCl and NH,C1 to yield additive compds contg 1 or 2 mols of HC1, from which they are separated by distn. Nakagawa(Ref 8) reviews the chemistry of poly acetylenes and gives 25 references. Polymerization of acetyl-... 

Vinyl Chloride. Vinyl chloride is an important monomer in the manufacture of polyvinyl chloride and vinyl polymers. Two basic transformations are in commercial use.188-190 The catalytic hydrochlorination of acetylene, once an important... 

The catalytic hydrochlorination of acetylene demands high-quality... 

Vinyl Chloride. Approximately 16.5 billion lb of VCM were produced in the United States in 1999, making it one of the largest-volume petrochemicals. It has been reported that more than 35 percent of the global production of chlorine goes to the manufacture of VCM. Although most of the VCM comes from EDC by the route described previously, it can be obtained from other sources, including its production in the catalytic hydrochlorination of acetylene and as a byproduct in the synthesis of other chlorinated hydrocarbons. 

Hydrogen chloride is an important industrial chemical. The anhydrous form is used in making alkyl chlorides and vinyl chloride from olefins and acetylene, respectively, and in hydrochlorination, alkylation, and polymerization reactions (Sax and Lewis 1987). The hydrated form of hydrogen chloride is hydrochloric acid, which also is used in idustrial processes. 

In this reaction, vinyl chloride, which is formed by the hydrochlorination of acetylene with hydrogen chloride, was not observed from the reaction mixture. This result shows that vinyl chloride does not participate in the formation of dichlorovinylsilane.82... 

Vinyl chloride is produced in the following industrial reactions (1) the thermal cracking of 1,2-dichlor-oethane, which is produced by the chlorination and/ or oxychlorination of ethylene and (2) the hydrochlorination of acetylene. The vast majority of vinyl chloride is used for the production of polyvinyl chloride (PVC) and the manufacture of copolymers with monomers such as vinyl acetate or vinylidene chloride. A much smaller proportion of vinyl chloride is used in the production of chlorinated solvents - primarily trichloroethanes. 

Use Production of vinyl chloride from acetylene and alkyl chlorides from olefins, hydrochlorination (see rubber hydrochloride), polymerization, isomerization, alkylation, and nitration reactions. 

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. 

As in steam cracking, a large number of by-products is produced. Some of them result from the consecutive reactions of the chlorination of vinyl chloride and of its derivatives obtained by dehydrochlorination (tri-, tetra-, pentachloroethane, perchloro-ethane, di-, trichloroethylene. perchloroethyleneX and the others from the hydrochlorination of vinyl chloride il.l-dichloroethane), while others result from decomposition reactions (acetylene, cokei or conversion of impurities initially present (hydrocarbons such as ethylene, butadiene and benzene, chlorinated derivatives such as chloroprene, methyl and ethyl Chlorides, chloroform, carbon tetrachloride, eta, and hydrogen) ... 

Balanced processes, which combine hydrochlorination with chlorination, offer an answer to the problem of the by-production of hydrochloric arid. In so far as they include the production of acetylene using cheap energy (nudear-generated electridty for example) or by operating on dilute streams (Kureha process), they may prove economically attractive. In face they involve a high capital expenditure, their operation is sometimes delicate, and the utilization of many of their by-products is uncertain. 

I Preparation of Chloroolefins and Diolefins by Hydrochlorination. When ia gaseous mixture of acetylene and hydrogen chloride is passed through a reaction chamber packed with highly activated charcoal or silica gel I impregnated with a solution containing about 20 per cent calcium chloride,... 

Figure 9-3. Technological scheme of production of the vinyl chloride monomer (1) plasma-chemical pyrolysis (2) cleaning from higher unsaturated hydrocarbons (3) hydrochlorination of acetylene (4) chlorination of ethylene (5) thermal pyrolysis of dichloroethane.

---