423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
210 | DF | MODIFYING OR REMOVING COMPONENT OF NORMALLY GASEOUS MIXTURE {11} |
220 | DF | .~ Carbon dioxide or hydrogen sulfide component {9} |
226 | .~.~ Utilizing organic reactant {2} | |
227 | DF | .~.~.~> Phenolate or phenolic type |
228 | DF | .~.~.~> Amine {1} |