4.2 Flashcards
alchohol general formulae
CnH2n+1OH
boiling point of alcohols
increases as chain length increases, is higher than that of alkenes due to hydrogen bonding
impact of branching on boiling point
branching reduces boiling point due to reduced surface contact
solubility in water of alcohols vs alkenes
alkenes insoluble in water, alcohols are soluble in water because they are polar and from hydrogen bonds
primary alcohol
OH group is attached to a carbon that is attached to one other carbon / has 2 hydrogens attached to it
secondary alcohol
OH group is attaches to a carbon that is attached to 2 other carbons / has one hydrogen attached to it
tertiary alcohol
OH group is attached to a carbon that is attached to 3 other carbons / has no hydrogens attached
what is used to oxidise alcohols
potassium dichromate shown as K2Cr2O7 / H2SO4 or Cr2O7 ^-2 / H^+
what does potassium dichromate look like
orange solution that turns green when reduced
oxidation of tertiary alcohols
not oxidised under these contidions, for it to oxidise the C the OH is attached to must have a H
oxidation of secondary alcohols
oxidise to form keytones
ketones
functional group C=O not at the end of the chain, names end in -one
oxidation of primary alcohols
oxidise once to from aldehydes under distillation and can oxidise further to form carboxylic acids under reflux
aldehydes
C=OH functional group at the end of the chain end in -anal
alcohols into alkenes and back
H2O can be removed from alcohols in the presence of heat and a H3PO catalyst. The OH is removed from one carbon and the H from the adjacent carbon forming a c=c bond
alcohols into haloalkanes
the OH group can be substituted for a halide ion in the presence of a halide salt solution and acid catalyst
nucleophylic substitution
the halo-carbon bond becomes polar leaving it open to attack by nucleophiles. The nucleophile uses its Lone pair to provide the electrons for a new bond displacing the halogen
nucleophile
electron pair donor - will probably have a lone pair
problems with CFCs / haloalkanes
in the atmosphere the halogen radical will react with ozone to from a halogen oxygen radical that reacts further with ozone. overall reaction O3 + O -> 2 O2
infrared spectroscopy
works by firing IR radiation at a compound. Different bonds absorb different amounts and frequencies of IR radiation. Looking at the absorption spectra allows you to identify the bonds in compounds
stages of spectroscopy
vaporisation, ionisation, acceleration, deflection, detection
