| 204 / | HD | CHEMISTRY: ELECTRICAL AND WAVE ENERGY |
| * | DD | PROCESSES AND PRODUCTS {7} |
| 157.15 | DF | .~ Processes of treating materials by wave energy {6} |
| 157.6 | DF | .~.~ Process or preparing desired organic product containing at least one atom other than carbon and hydrogen {16} |
| 157.87 | DF | .~.~.~ Carboxylic acid or derivative product produced {2} |
| 157.88 | | .~.~.~.~ Oxygen other than as part of a carboxylic acid or derivative moiety |