Chapter 17 - Carboxylic Acids

^^The term oxalic acid comes from one of its biological sources, plants of the genus Oxalis, one of which being rhubarb.^^ * Adipic acid is one of two monomers needed to create the polymer nylon 66. (as shown in the image attached). * The common names for the dicarboxylic acids oxalic through adipic are remembered using a mnemonic phrase. “Oh my goodness, such delicious apples.”
A carboxylic acid with a carboxyl group attached to a cycloalkane ring is called by first giving the ring's name and then adding the suffix -carboxylic acid. * The ring's atoms are numbered starting with the carbon-containing the -COOH group. * Benzoic acid is the most basic aromatic carboxylic acid. * Numbers are used to denote the placement of substituents relative to the carboxyl group when naming derivatives.
Certain aromatic carboxylic acids are often known by their common names. * 2-hydroxybenzoic acid, for example, is more often known as salicylic acid, a term derived from the fact that this aromatic carboxylic acid was initially isolated from the bark of the willow, a tree in the genus Salix.

%%Aromatic dicarboxylic acids are called by prefixing dicarboxylic acid with benzene (e.g., 1,2-benzenedicarboxylic acid and 1,4-benzenedicarboxylic acid).%%
Each is commonly recognized by its common name: phthalic acid and terephthalic acid.
Terephthalic acid is one of two organic components necessary for the manufacture of Dacron polyester, often known as Dacron
When using common names, the Greek letters a, b, g, d, and so on are frequently employed as a prefix to find substituents. * In a carboxylic acid, the a-position is adjacent to the carboxyl group; an a-substituent in a common name is equal to a 2-substituent in an IUPAC name.
GABA is an inhibitory neurotransmitter found in the human central nervous system. * Alanine is one of the 20 amino acids generated from proteins. * Carboxylic acid IUPAC names are generated from the parent alkane by removing the suffix -e and adding -oic acid. * %%There is no need to assign a number to the carbon with the carboxyl group because it is known to be carbon 1.%% * Most functional groups are preceded by the carboxyl group.
Dicarboxylic acids are referred to as -dioic acids, and the parent chain contains both carboxyl groups. * A carbonyl group is linked to an!OH group in a carboxylic acid (-COOH). * A carboxyl group is polar, and carboxylic acids are connected by hydrogen bonding into dimers in the liquid and solid phases. * Carboxylic acids have higher boiling temperatures and are more soluble in water than equivalent molecular weight alcohols, aldehydes, ketones, and ethers. * A carboxylic acid is made up of two separate polar regions: a polar hydrophilic carboxyl group that promotes water solubility and a nonpolar hydrophobic hydrocarbon chain that inhibits water solubility. * %%Because the hydrophilic carboxyl group more than balances the hydrophobic hydrocarbon chain, low-molecular-weight carboxylic acids are indefinitely soluble in water.%%
However, as the carbon chain lengthens, the hydrophobic group takes over and water solubility declines. * pKa values for aliphatic carboxylic acids range from 4.0 to 5.0. * The higher acidity of carboxylic acids compared to alcohols is explained by charge delocalization via resonance in a carboxylate anion relative to an alkoxide ion, as well as the electron-drawing inductive action of the carbonyl group.
Electron-withdrawing substituents next to the carboxyl group increase its acidity through the inductive action. * The oxidation of primary alcohols and aldehydes can be used to produce carboxylic acids. * When a Grignard reagent is treated with carbon dioxide (CO2), it produces the magnesium salt of a carboxylic acid, which, when protonated with aqueous acid, yields a carboxylic acid.
Although heating is necessary, lithium aluminum hydride (LiAlH4) converts a carboxylic acid to a primary alcohol. * Other reducing agents, such as catalytic hydrogenation and NaBH4, cannot reduce a carboxylic acid, therefore they can be used to decrease other functional groups in the same molecule without damaging the carboxylic acid. * $Fischer esterification is the process of producing an ester by combining a carboxylic acid with an alcohol in the presence of an acid catalyst such as sulfuric acid.$ * $Fischer esterification can be reversed.$ * When a carboxylic acid is treated with diazomethane (CH2N2), a methyl ester is produced in high yield.