alcohols

trend in boiling point

as chain length increases, number of e- per molecule increases, so induced dipole forces get stronger, boiling point increases

so volatility and flammability decrease

viscosity

trend in difference between boiling point of alkane and alcohol

-decreases

-only one hydrogen bond per alcohol molecule

-molecule becomes more dominated by non-polar hydrocarbon chain

-molecule becomes more bulky, harder to form hydrogen bonds

-number of e- increases so induced dipole forces get stronger so boiling point becomes more dependent on ID forces

what happens when alcohol and water are mixed

-hydrogen bonds are made between water and alcohol molecules

-energy released when new H bonds from compensate for energy required to break original H bonds

trend in alcohol solubility in water

-decreases

-molecule more dominated by large hydrocarbon chain, which obstructs formation of H bonds with water

-chain interacts more with other chains by ID forces

-energy released when H2O and alcohol interact isn’t sufficient to compensate for energy required to overcome intermolecular forces

oxidation of ethanol (primary alcohol)

-use acidified potassium dichromate (H+/ K2Cl2O7)

-aldehyde and water (1st stage) (immediately distil to keep aldehyde as it has a low boiling point due to no hydrogen bonding)

-potassium dichromate turns orange to green

-carboyl (C=O)

-carboxylic acid (2nd stage), for complete oxidation, reflux

oxidation of propan-2-ol (secondary alcohol)

-ketone (propanone) + water

-use acidified potassium dichromate (K2Cl2O7) which turns orange to green, and reflux

-ketone has no hydrogens attached so 2nd stage of oxidation isn’t possible, and tertiary alcohols can’t be oxidised

-e.g. CH3CHOHCH3 + O => CH3COCH3

-carbonyl group (C=O)

production of ethanol

-ethene + water = (phosphoric acid catalyst) = ethanol

-100% atom economy

trend in solubility of carboxylic acids

-when molecule gets to a certain size, harder for water molecule to form hydrogen bonds with carboxylic acid molecules

-they’re weak acids as their molecules only partially dissociate into ions in aq solutions

esterification: ethanoic acid + pentan-1-ol

-alcohol + carboxylic acid = (conc acid catalyst + heat) = ester + water

-OH from carboxylic acid and H from alcohol make water

-pentyl ethanoate

how does branching affect solubility of an alcohol

-more branching increases solubility

-weaker induced dipole forces to overcome, less energy required to overcome them

formation of induced dipole forces

-random movement of electrons in molecule results in instantaneous dipole, which induces a dipole on adjacent molecule

2 molecules attract each other

reaction of alcohol with halogenating agent to make haloalkanes

-nucleophilic substitution

-produces haloalkane

-OH replaced by halogen

-condensation

-conc. sulphuric acid catalyst

dehydration of alcohol to make alkene

-elimination reaction

-alcohol heated with conc. phosphoric acid

reaction/hydration of alkene to make alcohol

-steam

conc. phosphoric acid catalyst (H+ act as catalyst)

-e.g. ethene + steam = ethanol

reaction of haloaklane to make alcohol

-hydrolysis

-NaOH

-nucleophilic substitution

-:OH- is nucleophile