Chlorobenzene, benzylation chlorination

Other sources of by-product HCl include allyl chloride, chlorobenzenes, chlorinated paraffins, linear alkylbenzene, siHcone fluids and elastomers, magnesium, fluoropolymers, chlorotoluenes, benzyl chloride, potassium sulfate, and agricultural chemicals. 

Besides benzyl chloride, methyl- and/or chlorine-substituted benzyl chlorides, phenethyl chloride, etc. are also successfully employed to give 2 -diaralkylaminofluorans in excellent yield. However, aryl halides such as chlorobenzene and bromobenzene hardly enable the reaction, though aryl iodides such as iodobenzene give 2 -diarylaminofluorans in low yield. 

The chemical properties of the chlorobenzenes and chloroethylenes differ strikingly from those of saturated aliphatic chlorine compounds and of aromatic compounds with chlorine substituted in a side chain. For example, methyl chloride and benzyl chloride are hydrolyzed by boiling alkali, giving the corresponding alcohols, whereas chlorobenzene is not affected by this treatment. In general there is a pronounced diminution in reactivity of a chlorine atom adjacent to an aromatic nucleus or double bond. 

An attempt has been made to analyse whether the electrophilicity index is a reliable descriptor of the kinetic behaviour. Relative experimental rates of Friedel-Crafts benzylation, acetylation, and benzoylation reactions were found to correlate well with the corresponding calculated electrophilicity values. In the case of chlorination of various substituted ethylenes and nitration of toluene and chlorobenzene, the correlation was generally poor but somewhat better in the case of the experimental and the calculated activation energies for selected Markovnikov and anti-Markovnikov addition reactions. Reaction electrophilicity, local electrophilicity, and activation hardness were used together to provide a transparent picture of reaction rates and also the orientation of aromatic electrophilic substitution reactions. Ambiguity in the definition of the electrophilicity was highlighted.15... 

Addition of dimethylformamide makes it possible to achieve essential increase in monoohlorobenzene yield. In this case the total current efficiency of the benzene chlorination products is 9056, 3B-33% substance yield, while the chlorobenzene current efficiency 15%. This effect mi t have been concerned with the enhancement of benzene solubility in the water phase. Furthermore dimethylformamide depresses side processes, concerned v/ith both electrochemical conversion of chlorine, formed on the electrodes and formation of dichlorobenzene. As fair as chlorination of benzene derivatives to the side oliain is concerned, the factors that influence the chemical chlorination (UV and more hard radiation, the presence of different initiators of free radicals formation) favorably affect the isolation of benzyl chloride, o-, m-, p-xylylchloric -. The current efficiency is more than 85%. 

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