... and other Water Treatment Chemicals. Amino Trimethylene Phosphonic Acid (ATMP)2-Phosphonobutane -1,2,4-Tricarboxylic Acid(PBTCA)CAS No. 37971-36-1Molecular Formula ... , once contacted, flush with water.Synonyms:PBTCA;PBTC;PHOSPHONOBUTANE TRICARBOXYLIC ACID;2-Phosphonobutane -1,2,4-Tricarboxylic Acid;2-Phosphonobutane-1,2,4-tricarboxylic acid PBTC; 2-Phosphonobutane -1,2,4-Tricarboxylic Acid