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carboxyl group

carboxyl group (kärbŏk´sĬl), in chemistry, functional group that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl group, OH, by a single bond. Carboxylic acids are compounds whose molecules contain a carboxyl group that is joined to a hydrogen atom, an alkyl group, or an aryl group by a single bond to its carbon atom. Dicarboxylic acids, compounds that contain two carboxyl groups, are important in a number of industrial processes. The four main types of reactions of carboxylic acids are chiefly due to either the weak acidity of the hydroxyl hydrogen or to the difference in electronegativity between carbon and oxygen. One type involves cleavage of the hydroxyl oxygen-hydrogen bond, e.g., reaction with an alcohol to form an ester or reaction with an alkali to form a water-soluble salt. A second type involves addition of an electron-rich species to the electron-deficient carbon atom of the carboxyl group. A third type is characterized by the joining of a carbon atom directly to the carboxyl group. A fourth type involves the loss of carbon dioxide (decarboxylation). The second and third types are similar to reactions of the carbonyl group; the carboxyl group may be thought of as a carbonyl group joined to a hydroxyl group.

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carboxyl

car·box·yl / kärˈbäksəl/ • n. [as adj.] Chem. of or denoting the acid radical −COOH, present in most organic acids: the carboxyl group.

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carboxyl group

carboxyl group The organic group –CO.OH, present in carboxylic acids.

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carboxyl

carboxyl The group -CO2H (also written as -COOH).

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Carboxyl group

Carboxyl group

A carboxyl group, also called a carboxy group, is a characteristic group of atoms found in organic molecules. Organic compounds that contain carboxyl groups are called carboxylic acids. The simplest carboxylic acid is the alkanoic acids.

The carboxyl group occurs on the end or side of a molecule. The group consists of a carbon (C) atom that forms two chemical bonds to one oxygen (O) atom and one chemical bond to a second oxygen atom. This second oxygen is also bonded to a hydrogen (H) atom. The arrangement is writtenCOOH or C(O)OH (which emphasizes the different chemical bonding between the carbon atom and one of the oxygen atoms).

The name carboxyl is actually a combination of the words carbonyl and hydroxyl, since the carboxyl group itself can be considered as a combination of carbonyl (CO) and hydroxyl (OH) groups.

Carboxyl groups are reactive. They are able to react with amine groups. When this occurs, they form peptide bonds that, in the process, release a molecule of water (H2 O). They are also able to react with alcohols, which have the general form (where n is a variable) Cn H2n+1 OH. In this instance, esters are formed in one of two ways: by the Mitsunobu reaction or the Fischer esterification.

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Carboxyl Group

Carboxyl group

A carboxyl group, also called a carboxy group, is a characteristic group of atoms found in organic molecules. Organic compounds that contain carboxyl groups are called carboxylic acids .

The carboxyl group occurs on the end or side of a molecule . The group consists of a carbon atom that forms two chemical bonds to one oxygen atom and one chemical bond to a second oxygen atom. This second oxygen is also bonded to a hydrogen atom. The arrangement is written -COOH or -C(O)OH (which emphasizes the different chemical bonding between the carbon atom and one of the oxygen atoms). The name "carboxyl" is actually a combination of the words "carbonyl" and" hydroxyl," because the carboxyl group itself can be considered as a combination of carbonyl (CO) and hydroxyl (OH) groups.

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