3.11 Amines Flashcards
What is the functional group of an amine?
R-N-H
|
H
What properties do amines have?
Soluble in water (hydrogen bonding
Boiling points are lower than corresponding alcohols (amines are less electronegative and alcohols have 2 lone pairs on oxygen so form strong hydrogen bonds - requires more energy to overcome)
What are the types of amines?
Primary
Secondary
Tertiary
Explain the types of amines?
Primary - 1 hydrogen on NH3 is replaced
Secondary - 2 hydrogens on NH3 are replaced
Tertiary - all 3 hydrogens on the NH3 are replaced
How is basicity of amines determined?
By the availability of the lone pair of electrons on the nitrogen atom
(The increasing inductive effect increases basicity)
NH2(benzene) - low
NH3 - mid
CH3NH2 - high
What are the two ways to form amines?
Adding cyanide to a halogenoalkane
Using excess ammonia with a halogenoalkane
How do you form an amine using cyanide?
The arrow goes from the lone pair from C≡N goes to the C with the halogen attached
The second arrow goes from the middle of the C-Cl bond on to the halogen
The product CH3CN is produced
+ 4[H] -> CH3CH2NH2
Reagent of [H] = NaBH4 in methanol
How do you form a primary amine using excess NH3 and a halogenoalkane?
The arrow goes from the lone pair on the NH3 to the C on the C-Cl
The second arrow goes from the middle of the C-Cl bond onto the halogen
The arrow goes from another NH3 onto a H on the NH3 connected
The second arrow goes from the middle of the N-H bond (the H that you just swiped off) onto the N
Products: CH3NH2 (methylamine) + NH4+Cl-
How do you form a secondary amine using excess NH3 and a halogenoalkane?
Take the CH3NH2 and the arrow goes from the lone pair on the N goes onto the C of CH3Cl
The second arrow goes from the middle of the C-Cl bond onto the halogen
The arrow goes from an NH3 onto a H on the NH2 connected
The second arrow goes from the middle of the N-H bond (the H that you just swiped off) onto the N
Product: CH3NHCH3 (N,N-dimethylamine)
How do you form a tertiary amine using excess NH3 and a halogenoalkane?
Take the CH3NHCH3 and the arrow goes from the lone pair on the N goes onto the C of CH3Cl
The second arrow goes from the middle of the C-Cl bond onto the halogen
The arrow goes from an NH3 onto a H on the NH connected
The second arrow goes from the middle of the N-H bond (the H that you just swiped off) onto the N
Product: CH3N(CH3)CH3 (N,N,N-trimethylamine)
How do you form a quaternary amine using excess NH3 and a halogenoalkane?
The arrow goes from the lone pair of CH3N(CH3)CH3 on the N onto the C of CH3Cl
The second arrow goes from the middle of the C-Cl bond onto the halogen
The reaction goes no further
An N with 4CH3 surround it, in square brackets with a + charge and a seperate Cl-
N,N,N,N-Tetramethylammonium Chloride
A quaternary ammonium salt
What are some uses of ammonium salts?
Surfactants
Used as:
Fabric softener
Hair conditioner
(They need two long alkyl chains)
