Nikolai Menshutkin

Nikolai Aleksandrovich Menshutkin (; – ) was a Russian chemist who discovered the process of converting a tertiary amine to a quaternary ammonium salt via the reaction with an alkyl halide, now known as the Menshutkin reaction.

Biography Menshutkin was born in a merchant family as the sixth son of Alexander Nikolaevitch Menshutkin. He graduated with honors from gymnasium in December 1857, but only by autumn 1858 managed to enroll to the Saint Petersburg State University, as he was still under the prescribed age of 16. He studied at the faculty of physics and mathematics and was nearly expelled in the autumn of 1861 due to some political disturbances. Nevertheless, by the spring of 1862 he attained the master's degree. During the last years he became interested in chemistry, which he studied under Dmitri Mendeleev. While he acquired a sufficient knowledge of theory he was lacking practice, as at that time the entire laboratory of the university consisted of only two small rooms. Therefore, he went abroad, and in the following three years spent two semesters with Adolph Strecker at the University of Tübingen, a year (1864–5) with Charles-Adolphe Wurtz at the University of Paris, and a semester with Adolph Wilhelm Hermann Kolbe at the University of Marburg. In 1890 Menshutkin discovered that a tertiary amine can be converted into a quaternary ammonium salt by reaction with an alkyl halide.

Menshutkin further studied the influence of isomerism among alcohols and acids on esterification and showed that, both in respect of rate and limit, the primary, secondary, and tertiary alcohols differ from one another, and that unsaturated differ from saturated alcohols. The molecular weight of the alcohol concerned has also a considerable influence on the result, the limit rising generally with molecular weight, although the rate is diminished. The first series of experiments were made with acetic acid and alcohols and were extended to a variety of acids. Subsequently, the rate of chemical change was studied in the case of the formation of amides and anilides by the action of ammonia and aniline on acids by means of the same method as was employed in the esterification experiments. Here again the influence of isomeric differences was equally manifest. These researches led on to others, such as the study of the mutual displacement of bases in homogeneous systems, and the influence of temperature on the rate of several reactions.

Menshutkin further studied the effect of different solvents on the reaction rates. Although the solvent is unaltered after the reaction, its influence on the reaction rate was significant.

Between 1889 and 1895 Menshutkin focused on amines, on the kinetics of their interaction with alkyl halogen compounds and its dependence on the isomerism. Continuing these investigations down to the end of his life, he succeeded in establishing a large number of other relations between the structure or constitution and chemical activity, as well as physical properties, such as boiling point, melting point and specific gravity. He is regarded as a pioneer in chemical kinetics, not for the priority, but for systematic development of this field.