Sunday, 24 July 2011


Biography of Adolf Wilhelm Hermann Kolbe

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German chemist, generally regarded as the founder of modern organic chemistry with his synthesis of acetic acid (ethanoic acid) – an organiccompound – from inorganic starting materials. He was first to applyelectrolysis to organic synthesis. Kolbe electrolysis of fatty (alkanoic) acids was the first known electrochemical synthesis.

Kolbe was a German chemist. He was born near Gottingen and educated there. Kolbe studied for three years (1838-42) with Friedrich Wohler, and then served as an assistant of Robert Wilhelm Bunsen at the University of Marburg in 1842. After one year in Marburg, Kolbe obtained his PhD for work originally begun under Wohler’s direction. Kolbe remained as Bunsen’s assistant for a total of three years (1842-45).

He spent 2 years (1845-46) at the London School of Mines, England, being an assistant to Lyon Playfair. From 1847 to 1851 Kolbe was engaged in editing the Handworterbuch der reinen und angewandten Chemie (Dictionary of Pure and Applied Chemistry) written by Justus von Liebig and Wohler. In 1851 he was appointed professor at Marburg succeeding Bunsen; by 1865 he had moved to the University of Leipzig and had begun to set up the largest and best-equipped laboratory of the time. As editor of the Journal fur praktische Chemie (Journal of Practical Chemistry, 1869), he was sometimes severely critical of the work of others.

At that time, it was beliefed that organic and inorganic compounds are independent from each other, and that organic compounds could only be created by living organisms. Kolbe believed that organic compoundscould be derived from inorganic ones, directly or indirectly, by substitution processes.

He validated his theory by converting carbon disulfide (considered as an inorganic material), in several steps, to acetic acid (typical organiccompound) (1843-45). Thus, he was the first to synthesize of an organiccompound from inorganic maretial. Previously organic chemistry had been devoted to compounds that occur only in living organisms.

Introducing a modified idea of structural radicals he contributed to the establishment of structural theory. He was a pioneer in the development of structural formulas for organic compounds; introduced the term “synthesis” into chemical usage; discovered trichloromethanesulfonic acid and nitromethane; predicted existence of secondary and tertiary alcohols; synthesized taurine, malonic acid, and potassium formate; determined the composition of lactic acid, alanine, and glycocol. With Sir Edward Frankland he found that nitriles can be hydrolyzed to the corresponding acids.

Kolbe synthesized salicylic acid and showed its value as a preservative. The process was named Kolbe synthesis (or Kolbe-Schmitt reaction), which works by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure (100 atm, 125°C), then treating it with sulfuric acid:

Kolbe Electrolysis:

His most important work was on the electrolysis of the fatty (alkanoic) acids. He was first to apply electrolysis to organic synthesis and showed that electrolysis of carboxylic acids effects decarboxylation; identified carbonyl as a functional group. During the reaction CO2 is cleaved off. The alkyl radicals dimerize to symmetric compounds

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