Fundamentals of General, Organic, and Biological Chemistry - Chapter 17 Carboxylic Acids

Flashcards covering key vocabulary and concepts from Chapter 17: Carboxylic Acids, focusing on their properties, names, acidity, reactions, and derivatives like esters, amides, and phosphoric acid derivatives.

Carboxylic acid

A compound that has a carbonyl group (C
A0
=O) with a bond to a hydroxyl group (-OH) that produces a carboxylic acid group (-COOH).

Esters (functional group)

Organic compounds that have an ester group (-OR) bonded to the carbonyl carbon (C
A0
=O).

Amides (functional group)

Organic compounds that have an amine group (-NH2, -NHR

A0
, or -NR

A0
2) bonded to the carbonyl carbon (C
A0
=O).

Hydrogen bond formation

An electrostatic force responsible for carboxylic acids and their derivatives boiling at higher temperatures compared with alkanes.

Carbonyl group substitution reaction

A reaction where a group (-Z) substitutes for a hydroxyl group (-OH) bonded to the carbonyl carbon of a carboxylic acid or its derivative.

Ester Hydrolysis

A reverse reaction where esters convert back to their original carboxylic acids.

Acyl-group

The part of a carboxylic acid remaining after removing the hydroxyl-group (-OH), important in biological acyl-group transfer reactions.

Acidity of Carboxylic Acids

The ability of carboxylic acids to release a proton (H+) from the carboxyl-group (-COOH) and establish an acid-base equilibrium.

Water-soluble carboxylic acids

Carboxylic acids with saturated, straight-chain R groups up to four carbons (e.g., butyric acid).

Volatile liquid carboxylic acids

Carboxylic acids with saturated, straight-chain R groups up to nine carbons.

Waxy carboxylic acids

Carboxylic acids with saturated, straight-chain R groups beyond nine carbons.

Functional group priority

A hierarchy in nomenclature where the most important functional group is named first, determining how to name a compound with multiple functional groups.

Naming Carboxylic Acids (IUPAC)

Named by replacing the final -e of the corresponding
R
parent alkane
R
with the suffix -oic acid.

Common Naming Convention (Carboxylic Acids)

Carbon atoms attached to the carboxylic group are identified by Greek letters, with the alpha (α) carbon representing carbon-2.

Formic Acid

HCOOH

Acetic Acid

CH3COOH

Oxalic Acid

HOOCCOOH

Salicylic acid

A colorless, bitter-tasting solid plant hormone and precursor for aspirin (acetyl-salicylic acid), known to be toxic.

Naming Acyl groups

Named by replacing the suffix -ic of the corresponding carboxylic acid with either -yl or -oyl (e.g., acetyl group from acetic acid).

Dicarboxylic acids

Compounds with two -COOH groups, named by including -dioic acid to the alkane name.

Unsaturated acids

Carboxylic acids named using the IUPAC system with the ending -enoic (e.g., propenoic acid for H2C=CHCOOH).

Carboxylate anion

The anion formed when a carboxylic acid dissociates, releasing a proton (H+).

Dissociation of Carboxylic Acid

A carboxylic acid dissociates to form a carboxylate anion and a proton (H+), establishing an acid-base equilibrium.

Naming Carboxylate Anions

Formed by replacing the -ic ending for the carboxylic acid with -ate.

Acid dissociation constant (Ka)

A measure of the comparative strength of an acid.

pKa

The negative logarithm (-log Ka) of the acid dissociation constant; a smaller pKa value indicates a stronger acid, and a larger pKa value indicates a weaker acid.

Neutralization reaction (Carboxylic Acids)

A reaction where carboxylic acids produce a neutral carboxylic acid salt (such as sodium acetate) and water (H2O).

Effect of electronegative atoms on acidity

More electronegative atoms on the alpha carbon of a carboxylic acid pull electrons away, making the O-H bond less stable and the hydrogen atom more easily removed, thereby increasing acidity.

Ester formation

The creation of an ester from a carboxylic acid reacting with an alcohol.

Carboxylic Acid Reactions with Alcohols/Amines

Chemical reactions where -OH or -NH2 functional groups substitute with the -COOH group, forming water (H2O) and an ester or an amide, respectively.

Esterification reaction

The reaction of a carboxylic acid with an alcohol in the presence of a strong-acid catalyst (e.g., sulfuric acid) to form an ester; these reactions are reversible.

Unsubstituted amides formation

Formed by the reaction of a carboxylic acid with ammonia.

Substituted amides formation

Formed by a reaction between carboxylic acids and primary or secondary amines, but not tertiary amines due to the lack of a hydrogen atom on the nitrogen.

Tertiary amines reaction with carboxylic acids

Tertiary amines do not form amides or water molecules because they lack a hydrogen associated with the amine nitrogen; only an ammonium salt can be formed.

Hydrolysis of Esters and Amides

The reverse chemical reactions of ester and amide formation, where they undergo hydrolysis to form carboxylic acids in addition to alcohols or amines.

Mechanism of Ester/Amide Hydrolysis

Involves a hydrogen atom (-H) and a hydroxyl-group (-OH) from a water molecule (H2O) breaking the covalent bond, following a carbonyl-group substitution pattern.

Ester Hydrolysis (net effect)

The net effect is the substitution of -OH for -OR', with the released -OR' forming a covalent bond with the remaining -H from the water molecule.

Amide Hydrolysis (net effect)

The hydrolysis reaction results in substitution of the -OH for -NH2, -NHR, or -NR2.

Acid-catalyzed hydrolysis of esters

A hydrolysis reaction of an ester facilitated by acids, representing the reverse of the esterification reaction.

Saponification reaction

An ester bond hydrolysis reaction using a base such as NaOH or KOH.

Amide Hydrolysis (stability)

Amides are stable in water, but acid and base hydrolysis can occur with heating, leading to different forms depending on pH.

Phosphate ester

A compound formed by a reaction of an alcohol with phosphoric acid.

Phosphoric acid

An inorganic acid with three different acidic hydrogen atoms, allowing it to form three different anions through serial dissociations.

Phosphate ester formation (from phosphoric acid)

Formed when phosphoric acid reacts with an alcohol, where the alcohol R-group can substitute for one, two, or three of the phosphate -OH groups.

Acidity of Phosphate mono-esters and di-esters

These are acidic due to dissociable hydrogen atoms and are present as anions in neutral or alkaline solutions.

Phosphoryl group

The -PO3
A0
2- group.

Di-phosphoric acid (pyro-phosphoric acid) / Tri-phosphoric acid

Formed when two or three molecules of phosphoric acid combine, losing water.

Anhydride

A molecule that loses a water (H2O) molecule, resulting in an ester or anhydride bond.

Di-phosphates and Tri-phosphates

Esters formed from anhydride-containing acids (like di-phosphoric or tri-phosphoric acid).

Phosphorylation

The transfer of a phosphoryl group from one molecule to another.

Adenosine triphosphate (ATP)

Provides phosphoryl groups in metabolism and is converted to ADP and AMP in energy-releasing reactions, central to
intermediary metabolism
.

Regulation by phosphoryl groups

The addition and removal of phosphoryl groups serve as a common mechanism to regulate the function of molecules, especially proteins phosphorylated on serine, threonine, and tyrosine amino acids.