Depto. Química Orgánica

Brief History
18th Century

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15/07/2017
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At the end of the 18th century it became evident that substances isolated from living beings had a peculiar behavior (they decomposed easily, were complex mixtures, etc.) that differentiated them from those obtained from mineral systems, which were much simpler. Lavoisier establishes the axiom that only pure substances will provide information relevant to the development of chemistry.

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Antoine Laurent Lavoisier (1743-1794): Chemist, economist, agricultural technician and public official in Paris. He placed emphasis on the quantitative aspects of chemical reactions, developed an alternative conceptual scheme to the phlogiston theory in use, explained the processes of combustion and respiration through the uptake of oxygen, and was a key figure in the development of modern chemical nomenclature. He was guillotined during the French Revolution for being a member of a tax collection office. Lavoisier was Secretary of the Treasury of the Commission that established the metric system of weights and measures.

Separation and purification methods (extraction and distillation) were perfected at the end of the 18th century. The animal and plant worlds become chemically related when Scheele isolates lactic acid from sour milk and plant materials.

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Carl Wilhelm Scheele (1742-1786): Apothecary of Uppsala and Köping in Sweden. He discovered and identified chlorine, oxygen (he observed that manganese dioxide heated to red hot produced a gas that he called "fire air" because of the sparks it produced in contact with hot coal dust), hydrogen fluoride, cyanide hydrogen, lactic acid, citric acid and other organic acids. He also discovered the adsorption of gases by carbon and the catalytic effect of mineral acids in the esterification of organic acids. His studies of plants and animals were very important for physiological chemistry.

Lavoisier determined that the known compounds that had been extracted from plants contained only carbon, oxygen and hydrogen. Those of animal origin sometimes also contained nitrogen. Dalton develops his atomic theory: a compound made up of several elements must have the simplest possible formula (water = OH); The difficulty grows in understanding how such a vast number of organic compounds could be obtained from so few chemical elements.

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John Dalton (1766-1844): Chemist, physicist and meteorologist from Manchester in England. Dalton and the Irishman Higgins independently applied the atomic concepts of Galileo, Boyle and Newton to the elucidation of chemical reactions. Dalton placed special emphasis on the weights of atoms. He was the first to describe the color blindness (color blindness) that he himself suffered from.
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