alchemy,alcohol

ALCHEMY

Pseudoscience focused on the attempt to change base metals into gold.

Ancient alchemists believed that, under the correct astrological conditions, lead could be “perfected” into gold. They tried to hasten this transformation by heating and refining the metal in a variety of chemical processes, most of which were kept secret. Alchemy was practiced in much of the ancient world, from China and India to Greece. It migrated to Egypt during the Hellenistic period and was later revived in 12th-century Europe through translations of Arabic texts into Latin. Medieval European alchemists made some useful discoveries, including mineral acids and alcohol. The revival led to the development of pharmacology under the influence of Paracelsus and to the rise of modern chemistry. Not until the 19th century were the gold-making processes of alchemists finally discredited.

ALCOHOL (CH₃CH₂OH)

Any of a class of common organic compounds that contain one or more hydroxyl groups (−OH) attached to one or more of the carbon atoms in a hydrocarbon chain.

The number of other substituent groups (R) on that carbon atom make the alcohol a primary (RCH2OH), secondary (R2CHOH), or tertiary (R3COH) alcohol. Many alcohols occur naturally and are valuable intermediates in the synthesis of other compounds because of the characteristic chemical reactions of the hydroxyl group. Oxidation (see oxidation-reduction) of primary alcohols yields aldehydes and (if taken further) carboxylic acids; oxidation of secondary alcohols, ketones. Tertiary alcohols break down on oxidation. Alcohols generally react with carboxylic acids to produce esters. They may also be converted to ethers and olefins. Products of these numerous reactions include fats and waxes, detergents, plasticizers, emulsifiers, lubricants, emollients, and foaming agents. Ethanol (grain alcohol) and methanol (wood alcohol) are the best-known alcohols with one hydroxyl group. Glycols (e.g., ethylene glycol or antifreeze) contain two hydroxyl groups, glycerol three, and polyols three or more. See also alcoholic beverage, alcoholism.

Source: Britannica encyclopedia