Chapter 27 Flashcards
What are amines?
Organic compounds derived from ammonia, NH₃, in which one or more hydrogen atoms in ammonia have been replaced by a carbon chain or ring
What is the formula of ammonia?
NH₃
What is an aliphatic amine?
Nitrogen attached to at least one straight/branched carbon chain (alkyl group, R)
What is the simplest aliphatic amine?
Methylamine, CH₃NH₂
What is an aromatic amine?
Nitrogen atom attached to aromatic ring (aryl group)
What is the simplest aromatic amine?
phenylamine, C₆H₅NH₂
What are amines classified as?
1) primary
2) secondary
3) tertiary
How are amines classified?
By the number of alkyl or aryl groups attached to the nitrogen atom
What are amines well known for?
Their effects on the body
How do you name a primary amine, with the -NH₂ group on the end of the chain?
Add -amine to the name of the alkyl chain
How do you name a primary amine, with the -NH₂ group on any other carbon but carbon-1?
Use the prefix amino- and add a number before to indicate the position of the amine group along the chain
How do you name a secondary/tertiary amine containing the same alkyl group?
1) use the prefixes di- or tri- to indicate the number of alkyl groups attached to the nitrogen atom
2) use the suffix-amine
When two or more different groups are attached to a nitrogen atom, what is the compound named as?
N-substituted derivative of the larger group
What is the name of CH₃NHCH₂CH₂CH₃?
N-methylprophlamine
What is the name of CH₃N(CH₂CH₃)CH₂CH₂CH₃?
N-ethyl-N-methylpropylamine
Why do amines behave as bases?
The lone pair of electrons on the nitrogen atom can accept a proton
When amine accepts a proton, what type of bond is formed between the lone pair of electrons on the nitrogen atom and the proton?
Dative covalent bond
ethylamine + proton —>
ethylammonium ion
What should you show when drawing the structure of amine?
lone pair
Are amines acids or bases?
bases
What do amines neutralise acids to make?
salts
CH₃CH₂CH₂NH₂ + HCl —>
CH₃CH₂CH₂NH₃⁺Cl⁻
2CH₃CH₂NH₂ + H₂SO₄ —>
(CH₃CH₂NH₃⁺)₂SO₄²⁻
Is ammonia an electrophile or nucleophile?
nucleophile
How do you form a primary amine?
1) ammonia + haloalkane —> ammonium salt
2) ammonium salt + aqueous alkali —> amine + salt + water
Why can ammonia act as a nucleophile in a substitution reaction with a haloalkane?
Ammonia has a lone pair of electrons on the nitrogen atom
What type of reaction is ammonia + haloalkane?
substitution reaction
1-chloropropane + ammonia —>
propylammonium chloride
CH₃CH₂CH₂Cl⁺NH₃ —>
CH₃CH₂CH₂NH₃⁺Cl⁻
propylammonium chloride + sodium hydroxide —>
propylamine + sodium chloride + water
CH₃CH₂CH₂NH₃⁺Cl⁻ + NaOH —>
CH₃CH₂CH₂NH₂ + NaCl + H₂O
What are the essential conditions when forming primary amines?
1) ethanol is used as the solvent
2) excess ammonia is used
Why is ethanol used as the solvent when forming primary amines?
Prevents any substitution of the haloalkane by water to produce alcohols
Why is excess ammonia used when forming primary amines?
Reduces further substitution of the amine group to form secondary and tertiary amines
Why is the reaction used for making primary amines not suitable for making a pure primary amine?
The product still contains a lone pair of electrons on the nitrogen atom that can react further with a haloalkane to form a secondary amine
primary amine + haloalkane —>
ammonium salt
CH₃CH₂CH₂Cl + CH₃CH₂CH₂NH₂ —>
(CH₃CH₂CH₂)₂NH⁺Cl⁻
How do you obtain a secondary amine from its salt?
By reacting the salt with sodium hydroxide