Medincine: Esterfication & Carboxylic Acids Flashcards
Between molecules ( only ) does hydrogen bonding occur
H-O
H-N
H-F
What is the trend of solubility of alcohol is in the water
Solubility in water decreases as length of the carbon chain increases
Why does solubility of alcohols in water decrease as the length of the of the carbon chain increases
increase the carbon chain = increases the proportion of the part of the molecule that cannot take part in hydrogen bonding
Eg. CH3 OH
CH3CH2 OH
( only OH takes part in hydrogen bonding )
Definition of a primary alcohol
Carbon with OH is connected to 1 other carbon
Example of a primary alcohol
and draw
Ethanol
Definition of a secondary alcohol
Carbon with OH is connected to 2 other carbons
Example of a secondary alcohol
and draw
Propan-2-ol
Definition of a tertiary alcohol
Carbon with OH is connected to 3 other carbons
Example of a tertiary alcohol and draw
2-methyl propan-2-ol
What can alcohols be oxidised to
Carbonyl group C=O
What are the possible products of oxidation of alcohols depending on the alcohol you start with
Aldehyde
Carboxylic acid
Ketone
What is the oxidising agent for oxidation of alcohols
Acidified potassium chromate (VII) solution ( K2 Cr2 O7 / H+(aq) )
What is the product on oxidation with potassium chromate solution and a primary alcohol and by what process is the product formed
Carboxylic acid ( reflux & Xs [O] Aldehyde ( distillation )
Eg.
1. ethanol —-> ( reflux & Xs [O] ) ethanoic acid
- ethanol —-> ( distillation [O] ) ethanal
What is the product and oxidation with potassium cream made to solution and a secondary alcohol and by what process is the product formed formed
Ketone ( reflux )
Eg.
Propan-2-ol —> ( reflux & Xs [O] ) propanone
What is the product and oxidation with potassium cream made to solution and a tertiary alcohol and by what process is the product formed
Do not oxidise
Therefore no products formed
What is the sign used for an oxidising agent
[O]
What is the original colour of potassium chromate solution before any reaction
Orange
What is the colour change in the oxidation of a primary alcohol with potassium chromate solution
Orange —> green
What is the colour change in the oxidation of a secondary alcohol with potassium chromate solution
Orange —> green
What is the colour change in the oxidation of a tertiary alcohol with potassium chromate solution
Orange —> Orange
What is the functional group of an aldehyde and give an example
H-C=O
Eg. Ethanal
What is the functional group of a key tone and give an example
C=O
Eg. Propanone
What is the functional group of a carboxylic acid
O=C-OH
(cooh )
Eg. ethanoic acid
What is the functional group of an acid anhydride
O=C-O-C=O
Eg. Ethanoic anhydride
What is special about functional group acid anhydride
It is symmetrical and when reacted with acid ( H+ ) Forms to carboxylic acid functional groups
What is the functional group of esters and give an example
O=C-O
( coo )
Eg. Methyl propanoate
What is the functional group of ethos and give an example
-O-
Eg. Meth -oxy- ethane
Definition of an elimination or dehydration reaction
A reaction where a small molecule is removed from a larger molecule leaving and unsaturated molecule
What are the conditions required for an elimination or dehydration reaction
Heated alumina ( Al2 O3 ) 300°C
Or
Reflux
Concentrated sulphuric acid ( H2 SO4 )
What is the product of alcohol is undergoing elimination or dehydration
Alcohols —> alkene + water
What two products are formed from the dehydration of butan-2-ol
- But-1-ene ( if loose OH & H on C1)
- But-2-ene ( it loose OH & H on C3 )
Look at notes for more clarification
What two ways can an eater be formed
- Alcohol + carboxylic acid
2. Alcohol + acid anhydride
How can an Ester be formed from the reaction of an alcohol and carboxylic acid and give reaction equation
Reflux with concentrated H2 SO4 / HCl
Alcohol + carboxylic acid Ester + water
What is the rule for naming esters formed from the reaction of an alcohol and carboxylic acid
Alcohol =yl
Carboxylic acid = oate
Eg. Methanol + ethanoic acid methYL ethanOATE
How can an eater be formed from the reaction of an alcohol and acid anhydride
Gentle warming because acid anhydride is very reactive
Eg.
Alcohol + acid anhydride —> Ester + carboxylic acid
