amines Flashcards
What are amines?
Ammonia derivatives
What is the bond angle of ammonia?
Approximately 107°
What type of bonding occurs between amine molecules?
Hydrogen bonding, but weaker than in alcohols
How do the boiling points of amines compare to those of alcohols?
Lower than those of comparable alcohols
What are the physical states of shorter chain amines at room temperature?
Gases
What type of smell do amines have?
Fishy smells
Which amines are soluble in water?
Primary amines with chain lengths up to about four carbon atoms
Are aryl amines soluble in water?
No, due to the benzene ring
What makes amines very reactive compounds?
Having a lone pair of electrons
What reaction is used to prepare aliphatic amines from nitriles?
Reduction of nitriles
What is the functional group in nitriles?
-CN
What can reduce nitriles to primary amines?
LiAlH4 followed by dilute acid or H2 with a nickel catalyst
What is the general method for preparing primary aromatic amines?
Reacting benzene with concentrated nitric and sulfuric acid to produce nitrobenzene, then reducing with tin and hydrochloric acid
What do aromatic amines commonly used for?
Organic synthesis, especially in dyes
What type of substitution reactions do amines undergo with haloalkanes?
Nucleophilic substitution
What products can result from nucleophilic substitution reactions with haloalkanes?
Primary, secondary, tertiary amines, and quaternary ammonium salts
What happens to the amines produced in nucleophilic substitution reactions?
They can react further with haloalkanes
What do amines form when reacting with acyl chlorides or acid anhydrides?
Amides
What is the role of quaternary ammonium salts in cationic surfactants?
The hydrocarbon tail is hydrophobic and the ionic head is hydrophilic
What is the reaction of amines with acids?
Amine + Acid → Ammonium Salt
How are primary alkylamines named?
By naming the alkane and keeping -an on the alkane, not alkyl
What is the basic property of amines?
They are Brønsted-Lowry bases (proton acceptors)
What affects the strength of amines as bases?
The availability of the lone pair of electrons on nitrogen
How does the presence of alkyl groups affect the base strength of amines?
More alkyl groups increase electron density on nitrogen, making it a stronger base
Which amines have the strongest base strength?
Tertiary > Secondary > Primary > Ammonia > Aromatic
What do amines form when they react with acids?
Ammonium salts
What are the products of the reaction between methylamine and nitric acid?
Methylammonium nitrate
What are the products of the reaction between diethylamine and sulfuric acid?
Diethylammonium sulfate
