Aldehydes and Ketones Higher Chemistry

Our Plan For Today Recap on oxidation of alcohols Aim: We are going to learn about the structures of aldehydes and ketones and how to name them. Recap on oxidation of alcohols Aldehydes (alkanals) and Ketones (alkanones) Naming aldehydes and ketones.

Recap on Oxidation of Alcohols Oxidised by acidified potassium dichromate. The alcohol is oxidised to form an aldehyde which is a member of the alkanal homologus series. [O]  + H2O ethanal ethanol

Secondary Alcohols [O]  Oxidised by acidified potassium dichromate. When a secondary alcohol is oxidised a ketone is produced, they belong to the homologus series, the alkanones. [O]  + H2O propan-2-ol propanone

Tertiary alcohols are not readily oxidised 

Aldehydes - Alkanals carbonyl group butanal Aldehydes can be categorised by the presence of a C=O known as a carbonyl group. In an aldehyde the carbonyl group (C=O) is at the end of a carbon chain. They are a member of a homologus series called the alkanals, which ends in –anal.

Naming Alkanals H CH3 H H O H – C – C – C – C – C – H H H H H 5 4 3 2 1 4-methylpentanal Number your carbons from the carbonyl end. Name any branches

Ketones - Alkanones H – C – C – C – C – C- H H H H H H O H H H H – C – C – C – C – C- H H H H H For a ketone, the carbonyl group (C=O) is attached to two other carbon atoms and is found mid-chain. They are a member of a homologus series called the alkanones, which ends in –one. The position of the carbonyl group must be indicated in the name e.g pentan-2-one.

Individual Tasks Stick in both sheets of appendix 2.11 Turn to page 21 of your work booklets and complete the tables for the straight chain alkanals and alkanones with up to 6 carbon atoms. Exercise 2.5 on page 29 of your work booklets