Chemistry of Organophosphonate Scale Growth Inhibitors: 2. Structural Aspects of 2-Phosphonobutane-1,2,4-Tricarboxylic Acid Monohydrate (PBTC.H_2O)

Konstantinos D. Demadis ； Raphael G. Raptisl ； Peter Baran

《Bioinorganic Chemistry and Applications》 2005卷 (2005/12) Pp. 119-134

https://doi.org/10.1155/BCA.2005.119

摘要

The crystal structure of PBTC, one of the most widely used scale inhibitors in cooling water treatment, exhibits a complicated network of hydrogen bonds that are formed between the water molecule of crystallization, the-P-OH and the-COOH groups. Industrial water systems often suffer from undesirable inorganic deposits, such as calcium carbonate, calcium phosphate(s), magnesium silicate, and others. Synthetic water additives such as phosphonates and phosphonocarboxylates are the most important and widely utilized scale inhibitors in a plethora of industrial applications. The design of efficient and cost-effective inhibitors, as well as the study of their structure and function at the molecular level are important areas of research. This study reports the crystal and molecular structure of PBTC (PBTC 2-phosphonobutane-1,2,4-tricarboxylic acid), one of the most widely used scale inhibitors in the cooling water treatment industry. Triclinic PBTC monohydrate crystallizes in the P space group with cell dimesions, a 7.671(1) Å, b 8.680(1) Å, c= 9.886(1) Å,α=65.518(2) deg,β= 71.683(2) deg,γ= 76.173(2) deg, V 564.20(11) Å^3, and Z 2. Bond distances in the-PO_3 moiety are 1.4928(10) A for the P=O double bond and 1.5294(10) Å and 1.5578(10) Å for the two -P-O(H) groups. P-C and C--O bond lengths fall in the normal range. A network of hydrogen bonds are formed between the water molecule of crystallization, the-P-OH and the-COOH groups.

關鍵字

phosphonates ； carboxylates ； PBTC ； hydrogen bonding ； scale inhibitor.