| Date | May 2018 | Marks available | 2 | Reference code | 18M.3.sl.TZ2.20 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Identify | Question number | 20 | Adapted from | N/A |
Question
Drug synthesis often involves solvents.
Identify a common hazardous solvent and a Green solvent that could replace it.
Markscheme
Hazardous solvent:
Any one of:
methanal/formaldehyde
methanol
chlorinated solvent/carbon tetrachloride/methylene chloride/dichloromethane
diethyl ether/ethoxyethane
benzene
OR
methyl benzene/toluene
OR
«1,2/1,3/1,4» dimethylbenzene/«ortho/o-/meta/m-/para/p-» xylene
Green solvent:
Any one of:
water
«supercritical/liquid» carbon dioxide/supercritical fluids
ethanol «only if replacing a hazardous solvent»
propan-2-ol/2-propanol/isopropanol «only if replacing a hazardous solvent»
propanone/acetone «only if replacing a hazardous solvent»
ethyl ethanoate/ethyl acetate «only if replacing a hazardous solvent»
organic carbonates/dimethyl carbonate/diethyl carbonate/ethylene
carbonate/propylene carbonate
ionic liquids
fluorous solvents
Accept correct names (either IUPAC or generic) or formulas.
Do not accept inorganic acids such as HCl, H2SO4, etc.
Accept any specific chlorinated solvent.
Accept other hazardous solvents.
Do not accept any solvent given as both hazardous and green.
Award [2] for combination “Hazardous solvent: dimethylformamide/DMF/N,N-dimethylmethanamide” AND “Green solvent: methanol «only if replacing a hazardous solvent»”.
Accept other green solvents but not “solvents from biomass/food waste”.
[2 marks]
