Alcohols, Ethers and Phenols Flashcards
What are alcohols and ethers?
alcohols and ethers are derivatives of water in which one or two of the H atoms has been replaced by an alkyl group
What is the effect of increasing the number of OHs and increasing chain length on solubility and boiling point?
increasing the number of hydroxyl groups increases the solubility of the molecule in water
increasing chain length increases the boiling point of the molecule and its solubility in non-polar solvents
- has more van der Waals and London dispersion forces
What is the effect of hydrogen bonding on alcohols and ethers?
hydrogen bonding makes the molecule more soluble in water because it can be surrounded be water molecules
increases boiling point
What are the properties of methanol?
can go through a series of oxidation in the liver = loss of hydrogen as methanol - solvent in varnishes, racing car fuel as methanal = formaldehyde - highly toxic and can cause blindness as methanoic acid = formic acid - highly toxic and can cause blindness
What is the effect of oxidation on alcohols?
alcohols can be oxidised to aldehydes and further oxidised to carboxylic acids
What are the properties of ethanol?
can be oxidised in the liver as ethanol - drinking alcohol as ethanal = acetyl aldehyde - less toxic than methanal/formaldehyde - causes symptoms of a hangover = interaction with the brain as ethanoic acid = acetyl acid - combination of ethanal and ethanoic acid causes bad breath = odour
What are the methods of preparing ethanol?
fermentation of sugar
- breakdown of sugar to carbon dioxide and ethanol by yeast enzymes
hydration of ethene
- requires an acidic catalyst = sulphuric acid or phosphoric acid
- requires a high temperature
What is the test for alcohols?
alcohol reacts with sodium
- sodium is a metal
substitutes the H atom on the OH with the sodium
What are phenols?
aromatic alcohols
- OH group on the benzene ring
Why are phenols stronger acids than alcohols?
Why are carboxylic acids more acidic than both of them?
phenol is acidic because it generates the phenoxide anion
- stabilised by the benzene ring = resonance structure
phenols are stronger acids than alcohols because they can be resonance stabilised
- makes them less reactive
- negative charge is not localised = delocalised pi electrons
carboxylic acids are resonance stabilised by two structures
- has 2 negatively charged oxygen atoms compared to phenols and alcohol one oxygen atom
What are the medicinal purposes of phenols?
active ingredient for marijuana
anti-fungal agent
anaesthetics
What are the properties of ethers?
similar boiling point to alkanes - cannot form hydrogen bonds with each other soluble in water - can form hydrogen bonds with water flammable - ethers are less flammable than diethyl ether low reactivity - make good reaction solvents
