In this study, we report the effect of various synthesis times (30-90 mins) for the synthesis of carbon nanotubes (CNT). Bio-hydrocarbon precursor namely palm oil was utilized as a starting material by thermal vapor deposition method. Ferrocene at 5.33 wt% was directly mixed with palm oil precursor. The CNT were deposited on silicon substrates and then characterized by field emission scanning electron microscopy., micro-Raman spectroscopy and thermogravimetric analysis. The density., quality and the purity of the CNT were found to be highly dependent on the synthesis time. The 60 mins was considered to be the optimum synthesis time with uniform diameter around 23.6-28.1 nm with highest quality (ID/IG ratio = 0.42) and purity (80.01 %).