3 Acyl chloride

Acyl Chlorides CH3 C O Cl ethanoyl chloride Acyl chlorides are much more reactive than carboxylic acids The Cl group is classed as a good leaving groups (to do with less effective delocalisation.) This makes acyl chlorides much more reactive than carboxylic acids and esters CH3COOH + SOCl2
CH3COCl + SO2 + HCl Formation of acyl chloride from a carboxylic acid Reaction: carboxylic acid
acyl chloride Reagent: SOCl2 Conditions: room temp H3C C O OH H3C C O Cl + SOCl2
+ SO2 + HCl Sulphur dichloride oxide (thionyl chloride) SOCl2 is a liquid Reaction with water Change in functional group: acyl chloride
carboxylic acid Reagent: water Conditions: room temp. RCOCl (l) + H2O
RCO2H + HCl (g) CH3 C O Cl + H2O
CH3 C O OH + HCl (g) Observation: Steamy white fumes of HCl are given off Change in functional group: acyl chloride
ester Reagent: alcohol Conditions: room temp. RCOCl (l) + CH3CH2OH
RCO2CH2CH3 + HCl (g) CH 3 C O Cl + CH3CH2OH
+ HCl Observation: Steamy white fumes of HCl are given off Reaction with alcohol C C O O C C H H H H H H H H This reaction for making esters is much better than using carboxylic acids as the reaction is much quicker and it is not a reversible reaction Reaction with ammonia Change in functional group: acyl chloride
primary amide Reagent: ammonia Conditions: room temp. RCOCl (l) +2NH3
RCONH2 + NH4Cl (s) CH3 C O Cl + 2NH3
+ NH4Cl (s) Observation: white smoke of NH4Cl is given off CH3 C O NH2 Reaction with primary amines Change in functional group: acyl chloride
secondary amide Reagent: primary amine Conditions: room temp. RCOCl +2CH3NH2
RCONHCH3 + CH3NH3 +ClCH3 C O Cl + 2CH3NH2
+ CH3NH3 +ClN-methylethanamide C NH CH3 Reaction with phenol. Change in functional group: acyl chloride
ester Reagent: phenol Conditions: room temp. RCOCl (l) + C6H5OH
RCO2C6H5 + HCl (g) CH 3 C O Cl + HCl Observation: Steamy white fumes of HCl are given off Reaction with phenol Phenols do not easily form esters with carboxylic acids but do so readily with acyl chlorides