WM1 (Alcohols, Esterification + Phenols) Flashcards
describe the physical properties of the alcohols
they are polar due to the polarised O-H bond
hydrogen bonds are strong giving them a higher BP than other substances with a similar Mr
solubility decreases as the hydrocarbon chain gets longer because the -OH group becomes less important
define primary, secondary and tertiary alcohols
primary are where the -OH is bonded to a carbon atom which is bonded to one other carbon atom
secondary is where the -OH is bonded to a carbon bonded to two other carbons
tertiary is where the -OH is bonded to a carbon bonded to 3 others
what does oxidation of an alcohol in excess with no reflux produce
an aldehyde
what does oxidation of an alcohol where the oxidising agent is in excess and in reflux produce
a carboxylic acid
describe what happens to the molecules of an alcohol in oxidation
the -OH group is converted to a carbonyl group
two H atoms are removed, one from the -OH and one from the C
what is the condition of oxidation of an alcohol
if there is a H atom on the C atom to which the -OH is attached
when a ketone is produced, why is it no oxidised further
because it would involve breaking a strong C-C bond
what does oxidation of primary alcohols with potassium dichromate solution produce
if with no excess oxidising agent, an aldehyde
if with an excess agent, a carboxylic acid
both turn the solution from orange to green
describe the products of oxidation of secondary alcohols with potassium dichromate solution
a ketone which turns the solution green
describe what happens when tertiary alcohols react with potassium dichromate solution
they do not oxidise so the solution remains orange, this is because they do not have a H attached on the C with the -OH group
define heating under reflux
a safe method for heating reactions involving volatile/flammable liquids
the liquid is boiled with a vertically mounted condenser so the vapour condenses and returns back into the reaction mixture.
describe the features of the dehydration of alcohols
they lose a molecule of water to form an alkene
a heated catalyst is needed of al2o3 at 300*c or under reflux with concentrated sulfuric acid
describe substitution of alcohols and the products
nucleophilic substitutions occur with halide ions in the presence of a strong acid and to produce haloalkanes
describe esterification
an alcohol reacts with a carboxylic acid to produce an ester and water
the reaction is slow unless a strong acid catalyst is present such as HCl or H2SO4
heated under reflux
distill and purify the products to obtain an ester
describe the reaction of an acid anhydride to form an ester
an acid anhydride reacts with an alcohol to form an ester and a carboxylic acid
anhydrides are more reactive than carboxylic acids
they react completely with an alcohol on warming to form a much higher yield of ester
