Hydrogen chloride reaction with acetylene

Acetjiene has found use as a feedstock for production of chlorinated solvents by reaction with hydrogen chloride or chlorine (6). However, because of safety concerns and the lower price of other feedstock hydrocarbons, very Htfle acetylene is used to produce chlorinated hydrocarbons in the United States (see Acetylene-derived chemicals). 

Adsorption studies revealed that both reactants can be adsorbed on active catalysts. For the reaction of acetylene with hydrogen chloride, the... 

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... 

Acetylene is condensed to vinylacetylene and divinylacetylene by cuprous chloride and ammonium chloride. Similar additions of other compounds containing an active hydrogen atom occur in the presence of various catalysts. Mercury salts ate most effective in the vapor-phase reaction of acetylene with hydrogen chloride to give vinyl chloride (100%). Basic catalysts such as potassium hydroxide, potassium ethoxide, or zinc oxide are used for the vinylation of alcohols, glycols, amines, and acids. Most of these reactions involve the use of acetylene under pressure, and few have been described as simple laboratory procedures. Chloroacetic acid, however, reacts with acetylene at atmospheric pressure in the presence of mercuric oxide to yield vinyl chloro-acetate (49%). ... 

The gas phase reaction of acetylene with hydrogen chloride uses mercuric chloride (8, 9) or other heavy metal halides as catalyst. It is important that the gas streams be dry and free from arsine, phosphine, or sulfur. Because ethylene is priced substantially lower than acetylene, most recent processes substitute ethylene for acetylene, and acetylene-based vinyl chloride plants have been disappearing. 

As has already been mentioned, reaction chromatography is especially recommended for the analysis of reactive labile compounds. Hydrogen chloride in a mixture with acetylene and 1,1-dichloroethane [98] was determined from the carbon dioxide formed in a reaction between hydrogen chloride and sodium hydrogen carbonate [120]. 

Mixed-gas method. In this method [148], naphtha is thermally cracked to form acetylene and ethylene. Dichloroethane is formed by reacting ethylene with chlorine, and vinyl chloride is obtained by thermal decomposition of dichloroethane with simultaneous formation of hydrogen chloride. Further, the reaction between hydrogen chloride and acetylene also gives vinyl chloride. 

Vinylidene fluoride, CH2=CF2, is obtained by the pyrolysis of 1,1-difluoro- 1-chloroethane, which in turn is produced from acetylene, vinylidene chloride, or 1,1,1-trichloroethane by reaction with hydrogen fluoride. Because of its low boiling temperature, —84°C, vinylidene fluoride is suspension or emulsion polymerized under pressure. Considerable head-head linkage quantities are produced in these polymerizations. 

Vlayl fluoride [75-02-5] (VF) (fluoroethene) is a colorless gas at ambient conditions. It was first prepared by reaction of l,l-difluoro-2-bromoethane [359-07-9] with ziac (1). Most approaches to vinyl fluoride synthesis have employed reactions of acetylene [74-86-2] with hydrogen fluoride (HF) either directly (2—5) or utilizing catalysts (3,6—10). Other routes have iavolved ethylene [74-85-1] and HF (11), pyrolysis of 1,1-difluoroethane [624-72-6] (12,13) and fluorochloroethanes (14—18), reaction of 1,1-difluoroethane with acetylene (19,20), and halogen exchange of vinyl chloride [75-01-4] with HF (21—23). Physical properties of vinyl fluoride are given ia Table 1. 

The photolysis of chlorodiazirine was investigated in several cases. From chloromethyl-diazirine (232) vinyl chloride was formed as the stable primary product of stabilization of chloromethylcarbene, with acetylene and hydrogen chloride as secondary products. Some 1,1-dichloroethane was assumed to have been formed through a linear diazo compound by reaction with HCl. Added HBr yielded 1-bromo-l-chloroethane (76MI5Q800). 

Hydrochloric acid may conveniently be prepared by combustion of hydrogen with chlorine. In a typical process dry hydrogen chloride is passed into a vapour blender to be mixed with an equimolar proportion of dry acetylene. The presence of chlorine may cause an explosion and thus a device is used to detect any sudden rise in temperature. In such circumstances the hydrogen chloride is automatically diverted to the atmosphere. The mixture of gases is then led to a multi-tubular reactor, each tube of which is packed with a mercuric chloride catalyst on an activated carbon support. The reaction is initiated by heat but once it has started cooling has to be applied to control the highly exothermic reaction at about 90-100°C. In addition to the main reaction the side reactions shown in Figure 12.6 may occur. 

The monomer from which the vinyl plastic polyvinyl chloride (PVC) is prepared. Vinyl chloride was originally made by passing acetylene and hydrogen chloride over a mercury chloride catalyst at a temperature of about 180 °C. Now made from ethylene chloride which is converted to vinyl chloride by contact with a catalyst at about 500 °C (900 °F) or by reaction with dilute caustic alkali at about 150 °C (300 °F). 

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). 

Hydrogen chloride undergoes addition reactions with carbon-carbon double and triple bonds. Many addition products of olefins and acetylenes are important industrial raw materials. It adds to ethylene forming ethyl chloride ... 

Similar proposals have been made to treat the enormous quantities of calcium chloride obtained as a by-product in many industries either to obtain chlorine (q.v.) or hydrogen chloride. J. T. Pelouze 14 showed that when calcium chloride is mixed with sand to prevent fusion, it is readily decomposed by steam at a red heat with the copious evolution of hydrogen chloride, and the reaction was the basis of the E. Solvay patents in which the calcium chloride was mixed with sand or clay. W. Bramley mixed the calcium chloride with iron ore before heating it in a stream of air for chlorine, or with-steam for hydrogen chloride. W. H. Seamon proposed to treat molten calcium chloride with acetylene to produce calcium carbide and hydrogen chloride. 

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