Lassar Cohn

Background

Cohn was born on September 6, 1858, in Hamburg, Germany.

Education

Cohn attended high school in Königsberg (now Kaliningrad, Russia). He then studied chemistry at Heidelberg and Bonn, and received his doctorate in 1880.

Career

Cohn was Privatdozent (1888) and then professor of chemistry (1894-1897) at Königsberg, at Munich (1897-1898), and again at Königsberg (1901-1902). He was associated with various industrial firms throughout his career; he conducted researches in organic and physiological chemistry and in chemical technology.

The most elaborate of Cohn’s investigations was the isolation of the acids in ox and human bile by means of saponification, acidification, and solvent extraction (1892-1898). By oxidizing cholic and dehydrocholic acids Cohn prepared bilianic and isobilianic acids in 1899. From the latter, he obtained another oxidation product called cilianic acid. The understanding of the structures of the bile acids and their oxidation products came with the work of Heinrich Wieland in 1912.

Cohn also studied the electrolysis of organic potassium salts (1889) and prepared several halogenated derivatives of salicylic acid (1905). He developed an improved nitrometer for the determination of nitrogen by the Dumas method (1901) and invented a new saccharimeter (1922). He also published papers dealing with the utilization and disposal of chemical waste materials from industrial processes. Cohn made a careful study of the sulfite waste liquor from cellulose factories, proposing that the waste matter, instead of polluting rivers, could be made beneficialk to crops. After chemical treatment to reduce acidity, it could be pumped into canals and thence to irrigated fields.

Cohn was a successful writer of popular books on chemistry. Two books were especially widely read: Die Chemie im täglichen Leben (1896), which appeared in twelve German editions and was translated into many languages, and Einführung in die Chemie in leichtfasslicher Form (1899), which appeared in seven German editions. Both books were written for the general public, the former stressing the practical applications of chemistry, the latter the theoretical principles. His Arbeitsmethoden für organisch-chemische Laboratorien (1891) was a valuable compilation of all the methods for particular laboratory operations in organic chemistry: drying, distillation, extraction, filtration, molecular weight determination, sulfonation, halogenation, nitration, and so forth. The book was widely used in Germany and was also successful in its English translations.

Achievements

• Cohn is best known for his conducted research in organic and physiological chemistry and in chemical technology. He published numerous works in these areas.

Works

More photos

• book

  • Die chemie im täglichen leben 1908
  • A Laboratory Manual of Organic Chemistry: A Compendium of Laboratory Methods for the Use of Chemists, Physicians, and Pharmacists 1928
  • Application of some general reactions to investigation in organic chemistry
  • Chemistry in Daily Life

References

• Dictionary of Scientific Biography Volume 3
  1971