| 700 / | HD | DATA PROCESSING: GENERIC CONTROL SYSTEMS OR SPECIFIC APPLICATIONS |
| 90 | DD | SPECIFIC APPLICATION, APPARATUS OR PROCESS {16} |
| 266 | DD | .~ Chemical process control or monitoring system {6} |
| 268 | | .~.~ Synthesis process {1} |
| 269 | DD | .~.~.~> Polymerization/trimerization |