CARBONYL COMPOUNDS - STRUCTURE Structurecarbonyl groups consists of a carbon-oxygen double bond the bond is polar due to the difference in electronegativity Difference ALDEHYDES - at least one H attached to the carbonyl group C = O H CH 3 C = O H H
CARBONYL COMPOUNDS - STRUCTURE Structurecarbonyl groups consists of a carbon-oxygen double bond the bond is polar due to the difference in electronegativity Difference ALDEHYDES - at least one H attached to the carbonyl group KETONES - two carbons attached to the carbonyl group C = O H CH 3 C = O H H CH 3 C = O C2H5C2H5 CH 3
or RCHO Aldehydes are named using the suffix –al. or HCHO is methanal Or C 6 H 5 CHO. Benzenecarbaldehyde
Name this Aldehydes Ethanal Propanal 2-Methylpropanal
Ketones are named using the suffix –one. Propanone (acetone)
Name the following ketones Butanone 3-Pentanone 3-Hexanone 2-methyl-3-hexanone
Oxidising alcohols Reaction conditions: 1.The oxidising agent is always acidified potassium dichromate written above the arrow like this: K 2 Cr 2 O 7 /H 2 SO 4 2.The reactants are the alcohol and “[O]” symbolising the oxidation agent 3. Heat is always needed
Potassium dichromate In its oxidised state it is a bright orange liquid
Problem. CH 3 CH 2 OH reacts with potassium dichromate. 1)What are the organic products? 2)Which product has a higher boiling point? 3)How could you isolate the aldehyde?
Reflux apparatus Clamp stand Cooling tube (tap water goes in at the top and out at the bottom continuously) Reaction container Heat source
Further oxidation of a primary alcohol Using a process known as REFLUX, the reaction contents are continually heated at their boiling point temperature, so HOTTER and LONGER heating then alcohol conversion to an aldehyde Still uses acidified potassium dichromate Primary + Oxidising Carboxylic + water alcohol agent acid
Draw out the conversation of ethanol to ethanoic acid using the displayed formula
Oxidation of secondary alcohols Like primary alcohols, also require acidified potassium dichromate and heat (but not reflux) Converts the alcohol into a ketone Write out, using displayed formula, the oxidation of hexan-2-ol to hexa-2-one
Oxidation of tertiary alcohols The carbon attaching to the OH doesn’t have any hydrogens attached to it, so these can’t be oxidised.