alcohols Flashcards
what are primary secondary and tertiary alcohols?
it all depends on which carbon atoms the oh group is bonded to.
what is the general formula of alcohols?
Cn H2n+1 OH
how can alcohols react to form halogenoalkanes?
they can react in substitution reactions- the reagents and method that you use depends on the halogenoalkane that you’re trying to make
what does reacting Alcohold with PCL5 or HCL produce?
it produces chloroalkanes. this reaction is the fastest if the alcohols is a tertiary alcohol
what happens if the OH is swapped for a bromide?
a bromoalkane is produced - substitution reaction. the reaction requires an acid catalyst, such as 50% concentrated H2SO4.
give an example of the formation of a promo alkane?
shake 2-methylpropan-2-ol with potassium bromide and and 50 % concentrated sulphuric acid. the potassium bromide reacts with the sulphuric acid to form hydrogen bromide. the hydrogen bromide then reacts with the alcohol to form a bromoalkane.
how do you make iodoalkanes?
using red phosphorus triiodide and iodine - reflux
what does the dehydration of alcohols form?
alenes. you can make them by eliminating water from alcohols in an elimination reaction. the alcohol is mixed with an acid catalyst such as concentrated phosphoric acid. the mixture is then heated.
what is the simplest way to oxidise alcohols?
to burn them. it does not take much to set an alcohol alight - ethanol turns with a pale blue flame - the c-c bonds and the c-h bonds are broken and the alcohol is completely oxidised- combustion reaction - if you burn them with plenty of oxygen then you get water and carbon dioxide as products.
what does the amount of alcohol that cane oxidised depend on?
it depends on its structure:
primary alcohols are oxidised to aldehydes and then to carboxylic acids
secondary alcohols are oxidised to ketones only
tertiary alcohols won’t be oxidised
what do aldehydes and ketones both contain
C=O bonds. there general formula is Cn CH2n O. aldehydes only have one alkyl group attached to the C=O where as ketones have two
how do you test whether a compound is an aldehyde or a ketone?
use benedict’s solution. if he’d with an aldehyde then the blue copper (II) ions are reduced brick red copper (I) ions
why and how are primary alcohols oxidised to aldehydes and carboxylic acids?
distil to produce aldehyde and reflex for carboxylic acid.
how do you produce an aldehyde
gently heat ethanol with potassium dichromate (VI) solution and sulphuric acid should produce ethanal, however the mixture should be quickly removed from the oxidising solution as soon as it is formed - can be done by gently heavy the excess alcohol with a controlled amount of oxidising agent in a distillation apparatus so the aldehyde is distilled off immediately.
how do you produce a carboxylic acid?
the alcohol has to be vigorously oxidised. it has to be mixed with excess oxidising agent and then heated under reflux.
