Direct conversion of Camellia japonica seed into biodiesel through non-catalytic transesterification

Abstract

Biodiesel (BD) (that is alternative to petro-diesel) has been used as carbon neutral fuel as a strategic measure for CO2 mitigation. BD has been produced via acid-/base-catalyzed transesterification of edible oils. Rectifying a conventional/commercialized platform for BD synthesis could offer a new opportunity to produce BD with a more sustainable manner. Indeed, the massive amount of wastewater to neutralize alkaline solution is generated from the conversion process of BD. The use of edible oils in BD production has been also discouraged due to ethical dilemma linked to crop price increase. In these contexts, it could be very desirable to convert valueless/inedible oils into BD through an environmentally benign conversion platform. To this end, non-catalytic transesterification of Camellia japonica seed/oil was mainly studied in this work. As a reference, base-catalyzed transesterification of Camellia japonica oil was also tested. Camellia japonica kernel contained the high content of oil (60.4 wt%). Non-catalytic transesterification of Camellia japonica oil resulted in 96.77 wt% BD yield at 370 °C in 1 min. However, base-catalyzed transesterification of Camellia japonica oil led to 86.13 wt% BD yield at 63 °C for 2 h. Non-catalytic transesterification of Camellia japonica seed was tested to directly convert oil in Camellia japonica seed into BD. The yield of BD from the direct transesterification of Camellia japonica seed was higher (37.14 wt% per dried biomass) than transesterification of Camellia japonica oil (35.42 wt%). Such fact offers that direct conversion of oil-bearing seed into BD could be realized non-catalytically.