Effect of pyrazolium ionic liquid halide content on in-situ transesterification of Castor Bean (Ricinus Communis L.) seeds

Currently, ionic liquids (ILs) have apprehended considerable attention as greener substitutions to volatile organic compounds. In this work, duplicate 1-methyl-2-(butyl-4-sulfonate) pyrazolium hydrogensulfate (MSBPHSO4) were synthesized by two different methods. It is observed that IL2 is significantly less stable and more viscous than IL1. To assess their catalytic actions, each IL was explored individually for in-situ transesterifying of Ricinus Communis seeds. Under similar reaction conditions, the percentage of methyl esters obtained from in-situ transesterification catalyzed by IL1 and IL2 were 88.5 and 76%, respectively. Hence, the use of IL free halide has the opportunity to achieve high esters content. At investigated optimal conditions with increasing the temperatures beyond 120 degrees C, in contrast to ILL IL2 led to significant drop in the product yields. This phenomenon means that higher temperatures offer greater affinity to chemisorb chloride impurities on IL2 surfaces that are sufficient to block the active site and hinder the progress of the reaction. Too, IL1 revealed an excellent catalytic reusability after ten successive running cycles. These results further prove that the halide pathway should be avoided during synthesizing such ILs for biodiesel preparation. In this study we have established a new way for separating IL from the biodiesel as well as glycerol by salting-out assisted liquid -liquid extraction with aqueous MgSO4. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.