Synthetic Halogenated Organic Substances

In addition to oxidation and reduction reactions, naphthalene readily undergoes substitution reactions such as nitration, halogenation, sulfonation, and acylation to produce a variety of other substances, which are used in the manufacture of dyes, insecticides, organic solvents, and synthetic resins. The principal use of naphthalene is for the production of phthalic anhydride, CgbLO,. 

When the organic acids are treated with the halides of phosphorus the hydroxyl group which they contain is replaced by a halogen atom. The compounds formed react readily with other substances, and are much used in synthetic work and in the study of the structure of substances of unknown constitution. The acyl chlorides are used for these purposes and not the iodides as in the case of the alkyl halides. The chlorides are very reactive substances. The bromides and iodides are of minor importance, and have not been very fully investigated. 

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