Chemistry · Ch 10 — Halogen Derivatives
Nomenclature of halogen derivatives
Nomenclature of halogen derivatives
Common names of alkyl halides are formed by naming the alkyl group followed by the halogen name used as an adjective ending in '-ide' -- for example methyl iodide or tert-butyl chloride. In the IUPAC system (Class 11 Chemistry, section 14.4.7) alkyl halides are named as haloalkanes, with the halogen cited as a prefix (chloro-, bromo-, iodo-, fluoro-) on the parent alkane chain, numbered to give the substituent(s) the lowest possible locants. Aryl halides are named as haloarenes in both the common and the IUPAC systems. For a disubstituted (dihalogen) derivative of an arene, the common-name system uses the prefixes ortho- (o-), meta- (m-) and para- (p-) for the 1,2-, 1,3- and 1,4-relationships respectively, while the IUPAC system always uses the numerals 1,2-; 1,3- and 1,4- directly instead of the letter prefixes -- so m-dichlorobenzene and 1,3-dichlorobenzene name the same compound. Table 10.1 lists the common and IUPAC names of a representative set of mono- and dihalogen derivatives, including cases like neopentyl chloride (1-chlor …
Worked out. Zinc chloride is a Lewis acid and can coordinate with the oxygen of an alcohol, which weakens the R-O bond and helps the hydroxyl group leave as part of a halogenation reaction. A mixture of concentrated hydrochloric acid and anhydrous zinc chloride made this way is called Lucas reagent, and its differing reaction rate with primary, secondary and tertiary alcohols (tertiary reacts fastest, primary slowest or not at all at room temperature) is used as a qua …