Ants, formic acid source

Since carboxylic acids are amongst the earliest organic compounds to be isolated from nature, a large number of them are known by their common names. The common names end with the suffix -ic acid and have been derived from Latin or Greek names of their natural sources. For example, formic acid (HCOOH) was first obtained from red ants (Latin formica means ant), acetic acid (CH C OOH) from vinegar (Latin acetum, means vinegar), but n ic acid (CH3CH2CH2COOH) from rancid butter (Latin butyrum, means butter). 

Many carboxylic acids were first isolated from natural sources and were given names based on their origin. Formic acid (Latin formica, meaning ant ) was obtained by distilling ants. Since ancient times acetic acid (Latin acetum, for vinegar ) has been known to be present in wine that has turned sour. Butyric acid (Latin butyrum, meaning butter ) contributes to the odor of both rancid butter and ginkgo berries, and lactic acid (Latin lac, for milk ) has been isolated from sour milk. 

Several aliphatic carboxylic acids have been known for centuries, and their common names reflect their historical sources. Formic acid was extracted from ants formica in Latin. Acetic acid was isolated from vinegar, called acetum ( sour ) in Latin. Propionic acid was considered to be the first fatty acid, and the name is derived from the Greek protos pion ( first fat ). Butyric acid results from the oxidation of butyraldehyde, the principal flavor of butter butyrum in Latin. Caproic, caprylic, and capric acids are found in the skin secrehons of goats caper in Lahn. The names and physical properties of some carboxylic acids are listed in Table 20-1. 

All the substances that cause these unpleasant and possibly lethal effects are chemicals, albeit manufactured by a plant, micro-organism, or animal. They may be simple irritant chemicals such as the formic acid in ant bites (formica is the Latin for ant), or complex protein molecules such as is found in bee venom. Proteins are relatively large molecules, one of the main building blocks of the body and also the main component of enzymes (biological catalysts). The venom of animals such as snakes often contains enzymes which degrade flesh. Mushrooms and toadstools are another source of poisonous chemicals, for example the Death Cap mushroom found in Britain which can be lethal if eaten. 

How are organic compounds named Long ago, the name of a compound was often based on the plant or animal source from which it was obtained. For example, the name for formic acid, a caustic compound isolated from certain ants, comes from the Latin word formica, meaning ant and alli-cin, the pungent principal of garlic, is derived from the botanical name for garlic. Allium sativum. 

The aliphatic carboxylic acids have been known for a long time, and as a result have common names that refer to their sources rather than to their chemical structures. The common names of the more important acids are shown in Table 18.1. Formic acid, for example, adds the sting to the bite of an ant (Latin formicQy ant) butyric acid gives rancid butter its typical smell (Latin butyrum, butter) ... 

Carboxylic acids have common names derived from Latin or Greek words that relate to their natural sources. For example, formic acid is obtained from ant secretions, in Latin, ant is formica hence the name formic acid. The names of acetic acid (acetum, vinegar), butyric acid (butyrum, butter) and stearic acid (stear, tallow) are derived in the same way. 

Prior to the development near the end of the nineteenth century of a formal system for naming organic compounds, many organic compounds had already been discovered or synthesized. Early chemists named these compounds, often on the basis of the source of the compound. Acetic acid (systematically called ethanoic acid) is an example it was obtained by distilling vinegar, and it got its name from the Latin word for vinegar, acetum. Formic acid (systematically called methanoic acid) had been obtained by the distillation of the bodies of ants, so it got the name from the Latin word for formicae. Many of these older names for compounds, called common or trivial names, are still in wide use today. 

Many carboxylic acids have common names that are derived from Latin or Greek words that indicate one of their natural sources. Methanoic acid is called formic acid formica, Latin ant). Ethanoic acid is called acetic acid acetum, Latin vinegar). Butanoic acid is one compound responsible for the odor of rancid butter, so its common name is butyric acid butyrum, Latin butter). Pentanoic acid, as a result of its occurrence in valerian, a perennial herb, is named valeric acid. Hexanoic acid is one compound associated with the odor of goats, hence its common name, caproic acid caper, Latin goat). Octadecanoic acid takes its common name, stearic acid, from the Greek word stear, for tallow. 

Stinging ants, source of formic acid, HCOOH. 

Formic acid and acetic acid are the two most important carboxylic acids. Formic acid is a source of irritation in the bites of ants and other insects or in the scratch of nettles. A liquid with a sharp, irritating odor, formic acid is used in manufacturing esters, salts, and plastics. Acetic acid is present in a concentration of about 5% in vinegar and is responsible for its odor and taste. Acetic acid is among the least expensive organic acids, and is therefore a raw material in many commercial processes that require a carboxylic acid. Sodium acetate is one of several common salts of carboxylic acids. It is used to control the acidity of chemical processes and in preparing soaps and pharmaceutical agents. 

A carboxylic acid contains a carboxyl group, which is a hydroxyl group attached to a carbonyl group. Many carboxylic acids have common names, which are derived from their natural sources. Formic acid is injected under the skin from bee or red ant slings and other insect bites. Acetic acid is produced when ethanol in wines and apple cider reacts with the oxygen in the air. Propionic acid is obtained from the fats in dairy products. Butyric acid gives the foul odor to rancid butter (see Table 14.2). 

The strongest carboxyhc acid is formic acid, H-COOH. Formic acid is released when red ants bite and when nettles are touched, and is the source of the strong irritation people feel. In fact, formic acid is so closely associated with ants that the Latin word for ant is the origin... 

Common names, such as formic (ant) and butyric (butter) acids, are based on the natural source of the acid. The positions of substituent groups are shown by Greek letters a, y, S, etc. Some have names derived from acetic acid, e.g., (CH,),CCOOH and C H,CH,COOH, are trimethylacetic acid and phenylacetic acid, respectively. Occasionally they are named as carboxylic acids, e.g. 

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