A comparison of attenuated total reflectance‐FTIR spectroscopy and GPC for monitoring biodiesel production

Abstract

Gel permeation chromatography (GPC) and attenuated total reflectance (ATR)-FTIR spectroscopy were used to monitor the products of transesterification of waste frying oil in methanol to FAME or biodiesel. To evaluate the reliability and reproducibility of each method, quantitative analyses of mixtures of standards (TG, DG, MG, FAME, and glycerol) as well as lipid products of transesterification were carried out. The reproducibility of each method was found to be within ±1-5%. The differences between the results of the two methods were less than ±2%. The GPC method showed good separation of the intermediate products MG and glycerol from the TG starting material and FAME, but DG were not completely separated from TG. GPC gave good quantitative results for MG and FAME, but the TG and DG analyses required correction, depending on the mole ratio of TG/DG. In contrast, ATR-FTIR spectroscopy could only give quantitative data for the sum of TG + DG + MG.

Response Surface Methodology: An Emphatic Tool for Optimized Biodiesel Production Using Rice Bran and Sunflower Oils

“…IR bands in the region 1425-1447 cm −1 for CH 3 asymmetric bending and 1188-1200 for O-CH 3 stretching, in all biodiesel IR spectra, clearly demonstrated the transformation of vegetable oils into biodiesel, while these IR bands were absent in the IR spectra of both rice bran oil and sunflower oils, as seen in Figure 3. for O-CH 2 groups in glycerol (moiety of triglycerides, diglycerides, and monoglycerides) were present in the IR spectra of rice bran and sunflower oils only, in accordance with the previous literature [24,25].…”

FTIR Analysis for Quantification of Fatty Acid Methyl Esters in Biodiesel Produced by Microwave-Assisted Transesterification

“…The peak at 1446 cm -1 correspond to the asymmetric stretching of CH 3 present in the biodiesel spectrum and absent in the refined oil spectrum (Soares et al, 2008). The peak at 1377 cm -1 can be attributed to the glycerol group OCH 2 (mono-, di-and triglycerides), which is present in the refined oil spectrum and should be absent in the FAME spectrum [17]. The stretching of OCH 3 , represented by the absorbance at 1196 cm -1 , is typical of biodiesel.…”

Homogeneously Catalyzed Transesterification of Nigerian <i>Jatropha curcas</i> Oil into Biodiesel: A Kinetic Study

“…10 μl of the sample was injected into an auto-sampler vials. The HPLC analysis was conducted according to the method proposed by Dubé et al and Darnoko and Cheryan [11,15].…”