Reactions of alcohols - WM Flashcards
How to oxidise an alcohol
it is heated with a suitable oxidising agent - (acidified potassium dichromate solution)
What happens to the alcohol when oxidised
the acidified potassium dichromate solution is an orange solution and when it oxidises something it itself gets reduced to green Cr3+ so a colour change is seen
Primary alcohol definition
when the carbon bonded to the OH is bonded to one other carbon
Secondary alcohol definition
when the carbon bonded to the OH is bonded to 2 other carbons
Tertiary alcohol definition
when the carbon bonded to the OH is bonded to 3 other carbons
What happens to primary alcohols when oxidised (and stages)
first they are oxidised to an aldehyde but this can be further oxidised to a carboxylic acid
https://www.chemistrystudent.com/images/ASOrganic/alcohols/organicchemistryalcoholsoxidation1.png
How to only produce an aldehyde when oxidising primary alcohols
you need to limit the oxidation by using the minimum amount of oxidising agent
distilling the product straight out of the mixture as it forms
Equation for only producing an aldehyde when oxidising primary alcohols (using ethanol)
CH₃CH₂OH + [O] -> CH₃CHO + H₂O
[O] means that the oxygen is from the oxidising agent
How to only produce a carboxylic acid when oxidising primary alcohols
you need to ensure oxidation goes as far as possible by:
using excess oxidising agent
heating the mixture under reflux
Equation for only producing an aldehyde when oxidising primary alcohols (using ethanol)
CH₃CH₂OH + 2[O] -> CH₃COOH + H₂O
What happens to secondary alcohols when oxidised (and stages)
they are oxidised in one stage and produces a ketone
https://images.squarespace-cdn.com/content/v1/5c5aed8434c4e20e953d6011/1627124486646-MGMQPDJULW6ZYWJ768YZ/Oxidation+secondary+alcohols.jpg
What happens to secondary alcohols when oxidised (and stages)
it cannot be oxidised (it would need a C-C bond to break). If a tertiary alcohol is heated with an oxidising agent the colour stays orange
Dehydration of alcohol definition
loss of H₂O
Reagents an conditions of dehydration of alcohols
pass vapour of an alcohol over a heated Al₂O₃ catalyst or heat under reflux width concentrated sulphuric acid - a dehydrating agent
Dehydration of alcohol reaction stages
https://cdn.teachoo.com/8d8302fc-adf2-4f9b-a1df-2c99a463a338/dehydration-of-ethanol—teachoo.jpg
What does dehydration of alcohol reaction produce
alkene and water
Dehydration reaction are examples of what reaction
elimination
Elimination reaction definition
this reaction is one in which a small molecule is removed from a larger molecule giving an unsaturated molecule
Diagram of apparatus of elimination reaction
https://d1ymz67w5raq8g.cloudfront.net/Pictures/480xany/9/4/3/510943_equipmentfordehydratingethanol_585008.jpg
Esterification definition
esters can be made from an alcohol and a carboxylic acid and is reversible
Conditions of esterification
heat under reflux with an acid catalyst - usually a few drops of conc sulphuric acid or conc hydrochloric acid
Stages of esterification
https://media.geeksforgeeks.org/wp-content/uploads/20240319163647/image-430.webp
