• remediation;
  • biofuels;
  • tailing ponds

The reclamation of mining operation tailings water is of major concern to the oil sands industry. Naphthenic acids (NAs) are recognized as a major toxic component in tailings water. The acid-catalyzed esterification of commercially prepared NAs to biodiesel was performed as a test case for the utilization of these toxic compounds. In a series of batch acid-catalyzed esterification reactions, the influence of reaction temperature, catalyst type, catalyst concentration, and methanol to oil ratio on the esterification was investigated. The NA esterification reactions were found to be positively dependent on temperature and catalyst concentration while large methanol to oil ratios had a negative effect on the esterification. Finally, sulfuric acid was identified as a preferred catalyst for the esterification compared to p-toluene sulfonic acid. The esterification was completed successfully at the relatively mild conditions used in commercial biodiesel production. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 406-410, 2013