(442d) Use of Deep Eutectic Ionic Liquid for Biodiesel Preparation From Base-Catalyzed Transesterification of Rapeseed Oil

Use
of Deep Eutectic Ionic Liquid for Biodiesel Preparation from Base-Catalyzed Transesterification of Rapeseed Oil

Wei Huang
^a, Shaokun Tang,*^aHua
Zhao ^b

^a Key Laboratory for
Green Chemical Technology of Ministry of Education, School of Chemical Engineering
& Technology, Tianjin University, Tianjin 300072, China

^b
Chemistry Program, Savannah State University, Savannah, GA 31404, USA

*Corresponding author. Tel: +86-22-27408578; E-mail address: shktang@tju.edu.cn

As a renewable and biodegradable fuel, biodiesel
has been attracting research attention for the last decade in the face of
diminishing oil supplies. To overcome hurdles of the conventional reaction and
purification processes for biodiesel preparation, a number of new approaches
have been actively pursued including new solid catalysts, novel reaction
process, and co-solvents in recent years. However, these new methods are
associated with new problems such as lower product yield, higher energy
consumption, higher costs and so on.

In our work, a deep eutectic ionic
liquid (DEIL), choline chloride and glycerol (1:2, molar ratio), was prepared and
used in the transesterification reaction of rapeseed oil to biodiesel catalyzed
by NaOH. Response surface methodology (RSM) and Box-Behnken Design (BBD) were employed to examine different
reaction parameters such as methanol/oil molar ratio, catalyst concentration
and DEIL concentration, and optimize the reaction conditions for achieving the
maximum yield of fatty acid methyl ester (FAME).

Our data have suggested that the FAME yield
of up to 88% could be obtained at the optimum conditions; this yield was higher
than that of the reaction under the same condition parameters without the
addition of DEIL (74%). A statistical analysis of variance (ANOVA) indicates
that a second-order polynomial model appears to represent the actual
relationship between the response and the significant variables, with a very low
probability value (0.0001) and a high satisfying determination coefficient (R²=0.9724).

The addition of DEIL to the transesterification reaction improved the FAME yield and enabled
an easy and thorough separation of glycerol from the reaction mixture during
and after reaction. This study exemplifies a cost-effective and environmental
benign approach to biodiesel production by using the DEIL as a co-solvent for
the transesterification reaction.

Keywords:
deep eutectic ionic liquid, biodiesel, transesterification,
base catalyst, response surface methodology