Alkyl halides—continued tertiary

Even this is not all If the alkylation were to continue, the secondary and the tertiary amines would be produced all together in the reaction mixture. The reaction comes to an end only when the tetra-alkylammonium salt R4N+ is formed. This salt could be the product if a large excess of alkyl halide R1 is used, but other more controlled methods are needed for the synthesis of primary, secondary, and tertiary amines. 

This work was continued later on by Menshutkin in Petersburg in 1890, who studied the quaternization of tertiary amines with alkyl halides - a reaction which now is commonly known as the Menshutkin reaction . Menshutkin found, for example, that the reaction rate between triethylamine and ethyl iodide increases with solvent polarity, up to a factor of 742 in benzyl alcohol relative to n-hexane as solvent(3). 

Methods reported this year for the reduction of alkyl halides to alkanes include the potassium-dicyclohexyl-18-crown-6 reduction of alkyl fluorides, sodium borohydride reduction of alkyl chlorides, bromides, and iodides (or sulphonate esters) under liquid-liquid phase-transfer conditions, and the selective reduction of tertiary alkyl, benzyl, and allyl halides with the borate (61). Continuing... 

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