An on-line biodiesel transesterification monitoring system was developed using a mid-FTIR (Fourier Transform Infrared) spectrometer equipped with a temperature controlled transmission flow cell. A variety of spectral regions were assessed to monitor functional group changes during the transesterification process of Canola oil. The resulting dynamic reaction curves generated were used to gauge reaction progress as well as the final product parameters and compared to its corresponding GC profile. The transesterification process assessed oil: methanol molar ratios ranging from 1:6 to 1:12 (mol/mol) and catalyst concentrations ranging from 0.33% to 1.67% ml/g. Both Beer's law and Partial Least Squares calibration models were developed to quantify the components of interest. On-line FTIR analysis was found to be workable, simple and an improvement over methods such as TLC or GC to monitor the transesterification reaction, providing reaction data in real time. Being able to obtain detailed dynamic information about the process as the reaction takes place provides for more control, the ability to adjust the process if required and allows for optimization to improve product yield and consistency.

An automated FTIR method for the determination of the base content (BC pKa ) of oils at rates of > 120 samples/h has been developed. The method uses a 5% solution of trifluoroacetic acid in 1-propanol (TFA/P) added to heptane-diluted oil to react with the base present and measures the ν(COO − ) absorption of the TFA anion produced, with calibrations devised by gravimetrically adding 1-methylimidazole to a heptane-TFA/P mixture. To minimize spectral interferences, all spectra are transformed to 2 nd derivative spectra using a gap-segment algorithm. Any solvent displacement effects resulting from sample miscibility are spectrally accounted for by measurement of the changes in the 1-propanol overtone band at 1936 cm -1 . A variety of oils were analyzed for BC 0.5, expressed as mEq base/g oil as well as converted to base number (BN) units (mg KOH/g oil) to facilitate direct comparison with ASTM D2896 and ASTM D974 results for the same samples. Linear relationships were obtained between FTIR and D2896 and D974, with the ASTM methods producing higher BN values by factors of ~1.5 and ~1.3, respectively. Thus, the FTIR BC method correlates well with ASTM potentiometric procedures and, with its much higher throughput, promises to be a useful alternative means of rapidly determining reserve alkalinity in commercial oil condition monitoring laboratories.