Download Carboxylic Acids: Nomenclature, Structure, Properties, Preparation, and Reactions and more Quizzes Organic Chemistry in PDF only on Docsity! TERM 1 Carboxylic acid nomenclature DEFINITION 1 For open chain carboxylic acids, counting the longest continuous carbon chain that contains the carboxyl group (COOH) as the parent chain and replacing the e ending of alkane with oic acid. Because carboxyl group is always at the end of the chain, it is considered as C1 and the position of the carboxyl group does not need to be specified in the name. If there are other functional groups presents in the molecule, the carboxyl group outrank the other functional groups. The other functional group are considered as substituents. When carboxyl group is attached to a ring, the parent ring is named( the final e ending is retained) and the suffix carboxylic acid is added. TERM 2 Structure and bonding DEFINITION 2 In the carboxyl group, C and O on the C=O bond are sp2 hybridized, while the O on OH part is sp3 hybridized. Carboxyl group has three resonance forms, thus electrons are delocalized on the COOH group. O atom on the C=O bond is most electron rich (nucleophilic), while the H on the OH part is most electron deficient (electrophilic). TERM 3 Physical properties DEFINITION 3 Carboxylic acids have higher boiling points than alcohols, ketones and alkenes due to formation of two hydrogen bonds between the hydroxyl group of each molecule and the carbonyl oxygen of the other. Carboxylic acids can form hydrogen bonds with H2O, thus they have similar solubility in H2O as alcohols do. TERM 4 Acidity of carboxylic acids DEFINITION 4 Carboxylic acids are the most acidic class of compounds that contain only C, H and O. Great acidity of carboxylic acids is attributed to stabilization of carboxylate ion (COO-)by inductive effect of carbonyl group and resonance stabilization of carboxylate ion. Electron-withdrawing substituent on the -carbon can help stabilize the carboxylate ion via inductive effect and thus increase the acidity of the carboxylic acid. The acidity of the benzoic acids with EWG at the ortho position is increased comparing to those with EWG at the meta and para positions. TERM 5 Salts of carboxylic acids DEFINITION 5 Carboxylic acids can be deprotonated by strong base (NaOH or KOH) to form carboxylate salts. For low molecular weight acids, sodium and potassium carboxylate salts are soluble in water.Unbranched carboxylic acids with 12-18 carbons give carboxylate salts that form micelles in water, which is the spherical aggregates with carboxylate ions (the polar head) on the outside and nonpolar tails (the R chain ) on the inside.
