MORE HYDROCARBON DERIVATIVES ...THE NOMENCLATURE CONTINUES
Carboxylic acids • A carboxylic acid is an organic compound that contains a carboxyl group • Vinegar contains acetic acid and citrus fruits contain citric acid • They are weak acids meaning they do not fully ionize like some inorganic strong acids (HCl)
HOW DO WE NAME THEM? • Carboxyl group will always be terminal, so its carbon is always carbons 1 • Note its position on the priority chart • Still count the longest chain that contains the carboxyl • Write the suffix –oic acid, after dropping the –e from the parent alkane. • Treat any alkyl sidechains as normal in the prefix, giving them the appropriate position number
LET'S TRY SOME! • 2-ethylhexanoic acid • 2-ethyl-3 methyl-pentanoic acid • Benzoic acid
Esters • The fresh, fruity aromas in natural substances like banana, peach and cherry fragrance is caused by compounds called esters. • The ester is formed from the chemical reaction between an alcohol and a carboxylic acid. We will study this CONDENSATION reaction further in the next chapter.
How do we name them? • We must identify the part of the ester that came from the acid as this will form the root of the name. • We name the parent acid, then drop the –oic acid suffix and replace it with –oate. • The alcohol portion is converted into the alkyl name (i.e.drop the –ol) • If there are side chains on the parent acid, then name them in a prefix
Let's try some! • n-propylmethanoate
ethers • Ethers have a historical use as anaesthetics, used for surgery after 1842 • Now safer anaesthetics are used and ethers are used as starters for diesel engines, aerosol propellant, solvents and platicisers. • Looks like this: R—O—R' • Formed from the condensation reaction of two alcohols
How do we name them? • The longest carbon chain is the R group and is referred to as the parent alkane. • The –O—R' , where the R' is the shorter carbon chain are referred to as the alkoxy group • This group is named by adding –oxy to the root name of the R' group. • For example: • CH3—CH2—CH2—O—CH3 • The shorter R-group is the methoxy and the root is propane, so the name is methoxypropane • You must state which carbon the alkoxy group is attached to in the parent alkane through a position number. • Any side chain on the parent alkane is named as an immediate prefix to the parent alkane.
Like this!! • 3-propoxy-4-methylhexane
amines • Amines are volatile organic derivatives that can have a fishy smell • They are diverse in their function from industrial to biological. We will explore more uses when you study their reactions. • The amine functional group contains a nitrogen bonded to at least one other carbon
How do we name them? • Identify the longest chain bonded to the nitrogen atom, numbering so that the nitrogen has the lowest number in the chain • Drop the –e on the parent alkane and replace it with –amine suffix. The position of the nitrogen comes before the –amine. • Primary, secondary and tertiary amines use "N" in the prefix to refer to the hydrocarbon(s) attached to the nitrogen. • Refer to the other R groups in an alpha manner in the prefix, preceded by the letter N
How does that work? • N-ethyl-N-propylheptan-3-amine
amides • Amides are hydrocarbon derivatives formed by the condensation reaction between an amine and a carboxylic acid
How do we name them! • Determine the longest chain that contains the carbonyl. This was the parent acid. • Drop the –e to create the root and add the suffix –amide • The carbonyl carbon is carbon #1 for the main chain. Treat alkyl side chains as per usual in the prefix • Use the N notation for the alkyl attachment to the secondary or the tertiary amine. • For tertiary amides, place the N-groups in alpha order • If the groups are identical then use N,N-di...followed by the name of the alkyl group
I know you're tired...but you have to practice to get better and faster! • Carboxylic Acids pg 61 #116125 • Esters pg. 65 #126135 • Ethers pg 69 #136146 • Amines pg 74 # 147158 • Amides pg 79 # 159169 • Overview pg 82 # 111