Superbases have also been defined semi-quantitatively as any species with a higher absolute proton affinity ( APA = 245.3 kcal\/mol ) and intrinsic gas phase basicity ( GB = 239 kcal\/mol ) than Alder 's canonical proton sponge ( 1,8-bis - ( dimethylamino ) - naphthalene ) .
Superbases have also been defined in terms of numbers ( semi-quantitatively ) as any species with a higher absolute proton affinity ( APA = 245.3 kcal\/mol ) and intrinsic gas phase basicity ( GB = 239 kcal\/mol ) than Alder 's canonical proton sponge ( 1,8-bis - ( dimethylamino ) - naphthalene ) .