Amines and Amides

Aminy are organic compounds derived from ammonia by replacing one or more hydrogen atoms with alkyl or aryl groups. They have a characteristic fishy odor and can act as bases. Amines react with acids to form salts and undergo various substitution reactions. Amidy are compounds containing the -CONH₂ group and are derived from carboxylic acids. They play important roles in biological systems, such as in proteins.

Definition: Primary amines have one alkyl group attached to the nitrogen atom, secondary amines have two, and tertiary amines have three.

Example: Reaction of methylamine with hydrochloric acid: CH₃NH₂ + HCl → CH₃NH₃⁺Cl⁻

Urea and Biuret Test

This page focuses on urea, its preparation, hydrolysis, and the biuret test for peptide bonds.

Urea:

• Prepared from carbon dioxide and ammonia
• Undergoes hydrolysis in acidic or basic conditions

Definition: Biuret test - A chemical test used to detect the presence of peptide bonds in proteins.

Key reactions:

1. Urea synthesis: CO2 + 2NH3 → CO(NH2)2 + H2O
2. Acid hydrolysis of urea: CO(NH2)2 + H2O + 2HCl → 2NH4Cl + CO2
3. Base hydrolysis of urea: CO(NH2)2 + 2NaOH → Na2CO3 + 2NH3

Highlight: The biuret test uses Cu(OH)2 in alkaline conditions to detect peptide bonds, resulting in a violet-pink color for positive results.

The page also includes a table summarizing various chemical tests, including the Trommer's test, test for polyhydroxy alcohols, and the biuret test, detailing their purposes, observations, and products.