Halogenation Hydrohalogenation

Addition. Addition reactions of ethylene have considerable importance and lead to the production of ethylene dichloride, ethylene dibromide, and ethyl chloride by halogenation—hydrohalogenation ethylbenzene, ethyltoluene, and aluminum alkyls by alkylation a-olefms by oligomerization ethanol by hydration and propionaldehyde by hydroformylation. 

Halogenation—Hydrohalogenation. The most important iatermediate is ethylene dichloride [107-06-2] (EDC) which is produced from ethylene either by direct chlorination or by oxychloriaation. Direct chlorination is carried out ia the Hquid or vapor phase over catalysts of iron, alumiaum, copper, or antimony chlorides, and at conditions of 60°C. Oxychloriaation is carried out ia a fixed or fluidized bed at 220°C with a suitable soHd chloride catalyst. 

Like NR, SBR is an unsaturated hydrocarbon polymer. Hence unvulcanised compounds will dissolve in most hydrocarbon solvents and other liquids of similar solubility parameter, whilst vulcanised stocks will swell extensively. Both materials will also undergo many olefinic-type reactions such as oxidation, ozone attack, halogenation, hydrohalogenation and so on, although the activity and detailed reactions differ because of the presence of the adjacent methyl group to the double bond in the natural rubber molecule. Both rubbers may be reinforced by carbon black and neither can be classed as heat-resisting rubbers. 

Add groups to a pair of atoms joined by a multiple bond Ex hydrogenation, halogenation, hydrohalogenation, hydration, hydroxylation. Two major types ... 

Liquid-phase processes such as oxidation, hydrogenation, sulfonation, nitration, halogenation, hydrohalogenation, alkylation, sulfonation, polycondensation, polymerization, etc. Examples oxidation of acetaldehyde to acetic acid... 

Properties Colorless liquid. D 0.7184 (20/4C), bp 75-77C, flash p-30F (-34.4C). Reactive with halogens, hydrohalogens, sulfur dioxide, and maleic anhydride. 

Chlorinations Catalyzed by Active Carbon. When carbon of different densities is subjected to superheated steam, its surface is vaporized, forming capillaries which have the property of absorbing gases and compressing them into much smaller volumes. This compression, possibly combined with the catalytic effect of the metal impurities present in the carbon, promotes reactions such as halogenation, hydrohalogenation, or dehydro-halogenation. The character of the metallic impurities, the absorption power of the carbon, the density of the carbon, and the method of capillary formation all materially influence the type of reaction and the life of the catalyst. Often materials are added to these carbons to modify their properties. 

Lower boiling fractions from the primary distillation are also used in the production of solvents. Ethylene is used to produce ethylene dichloride, efliylene glycol, ethanol, and ethyl benzene. Propylene is used to produce isopropyl alcohol. Halogenation, hydrohalogenation, alkylation, and hydrolysis reactions are used in these conversions. 

There are a large number of processes in chemical technology, which occur in liquid-gas systems, in particular, halogenation, hydrohalogenation, oxidation, and so on, where the main problem is obtaining a reaction mixture with a well-developed phase contact surface. Diffusion constraints are of special importance at high rates of chemical reactions. In this case, it is necessary to decrease the dimensions of devices to a dimension equal to the reaction zone size (intensive dispersion zones) in order to eliminate any dead zones. 

Key words Asymmetric halogenation, hydrohalogenation, styrene, cyclodextrin complex. 

Standard alkene reactions such as hydrogenation, halogenation, hydrohalogenation and isomerization as adapted to a diene polymer situation. 

Since 1,4-polyisoprene has a secondary carbon atom at the double bond it follows that it is generally more reactive to both free radicals and to carbonium ions than 1,4-poly butadiene. The typical addition reactions associated with the double bond suggest that the ultimate hydrogenated, halogenated, hydrohalogenated and isomerized diene polymers would have the same structure irrespective of the initial cis-ltrans- ratio. 

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