Alcohols Flashcards
What is hydration of ethene and what conditions are needed?
Hydration of ethene is when ethene is reacted with steam and phosphoric acid to break the double bond to make ethanol.
300 degrees and 60 atm.
The reaction of ethene is incomplete because he reaction is reversible. Every time the reagents are put through the reactor, only 5% of the ethene is converted and overall it’s 95%
What is fermentation of ethanol and what are the conditions?
Fermentation of ethanol is when yeast catalysed the reaction of the conversion of carbohydrates in to ethanol and carbon dioxide.
The conditions needed are the absence of air and 37 degrees. Also zymase in the yeast to catalyse the reaction.
The alcohol concentration is about 14%.
Explain the solubility of alcohols.
Only the first the alcohols on the homologous series are soluble in water.
Alcohols are soluble in water because they form hydrogen bonds between the o-h- polar groups of both the alcohol and water.
Solubility decreases as chain length increases because the larger part of the chain is non polar and this part does not make hydrogen bonds in water.
Explain the volatility in alcohols
Volatility is the ease in which a liquid turns into a gas.
Alcohols have high melting and boiling points because they form hydrogen bonds between the o-h molecules.
when boiling points increase, volatility decreases. So alcohols have low volatility.
Uses of ethanol in alcoholic drinks
Ethanol used in beverages is made via fermentation.
Barley, water and hops are combined together with years to produce beers and lagers.
Hops prevents bacteria from growing and spoiling the alcohol.
Spirits vodka and gin and produced in a distillery and have a higher alcohol content.
Uses of ethanol in methylated spirits
Methylated spirits are ethanol + little bit of methanol + coloured dye.
The methanol makes it extremely toxic and u drinkable.
Methylated spirits are used as solvents for removing paint or ink stains from clothing and as a fuel in spirit burners and camping stoves.
Uses of methanol as an additive
Methanol can be a petrol additive to high performance racing cars because it’s a clean burning fuel.
Methanol smells and tastes like ethan BUT IT IS SOOOO POISONOUS so don’t
Also an extremely important feedstock to the chemical industry because it can be converted to methanal and methanoic acid
What
What is used to oxidise alcohols (apart from heat)?
Acidified dichromate ions.
k2cr207 / H2so4
What happens when you gently heat a primary alcohol with acidified dichromate ions?
It becomes an aldehyde. For example, propanol will turn to propanal
What happens when you heat a primary alcohol strongly with acidified dichromate ions?
Becomes a carboxylate acid because it passes the aldehyde stage
What’s the colour change of acidified dichromate ions in the reaction of oxidation?
Goes from orange to green
What is made when you oxidise secondary alcohols with acidified dichromate ions?
Ketones ^_^
Why are aldehydes distilled off immediately?
To stop them from oxidising further and becoming carboxylic acids
What is esterification?
Esterification is where an alcohol is heated with a carboxylic acid and in the presence of an acid catalyst to make an ester.
It makes water because the OH of the alcohol and the H of the acid makes water. The two molecules form a covalent bond by sharing the oxygen molecule left over.
What is dehydration of an alcohol?
Dehydration is when an alcohol in the presence of an acid catalyst is dehydrated to make an alkene.
This happens because the OH group f the alcohol and the H makes water from the alcohol and it leaves a double bond
This happens under reflux using phosphoric acid
