(192o) Microscopic Study On Jatropha Curcas Cells In In Situ Transesterification Process

Kasim, F. H., Newcastle University

In situ transesterification is the integration of two processes, solvent extraction and reaction (transesterification) to produce biodiesel directly from oilseeds. Previous work on this topic, presented at AIChE 2010, demonstrated the technical viability of in situ transesterification of jatropha. In this project, the effects of molar ratio of methanol to oil and reaction time on in situ transesterification of Jatropha curcas L. (J.curcas) were investigated with a view to determining the effects on the morphology of the seed. The in situ transesterification was examined in 3 different ratios, 100, 300 and 600. Yield is a strong function of molar ratio, and this and previous studies indicate that very large molar excesses are required: here the respective biodiesel yields at these ratios were 1.9%, 74.6% and 86.9%. Microscopy was conducted to attempt to determine why such large excesses of methanol are required. It demonstrated that the cell walls were greatly affected by increasing molar ratio. The intact cell per area at 100 was the same as the unreacted sample, 1133 cell/ mm2. This then decreased to 200 cell/mm2 at 300 ratio and 33 cell/mm2 at 600 ratio. The intact cell count also decreased with reaction time. The cell count at 10 minutes reaction time was 666 cell/mm2, and reduced to 433 cell/ mm2 at 20 minutes. The cell count keep decreasing furthermore at 30 minutes to 100 cell/ mm2, before reached 0 cell/ mm2 at 40minutes. The yields increased over this period from 64.32% at 10 minutes to 72.9% at 20 minutes, 75.8% at 30 minutes, 80.9% at 40 minutes and 82.2% at 50 minutes. SEM of the seed before and after reaction gave further evidence of the changing integrity of the oilseed cells.