Transesterification and Reactive Extraction of Castor Oil for synthesis of Biodiesel/Biolubricant

Abstract

The use of non-edible vegetable oils as a substitute for petroleum fuel has gained popularity due to increased environmental contamination and depletion of petrochemical resources. There is high percentage of oil in castor seeds, that can be converted into biodiesel and biolubricant. Castor oil has high lubricity due to presence of higher percentage of (nearly 90%) ricinoleic acid. In comparison to other vegetable oils, ricinoleic acid having a double bond and a hydroxyl group, gives higher lubricity to the castor oil and its alkyl esters. The study comprises production of castor oil alkyl esters from castor oil using different alcohols such as methyl, ethyl, propyl and butyl alcohol. The reaction parameters are optimized to get effective yield for all the four alkyl esters. Propanol was used as both an extracting solvent and a transesterification reagent in the reactive extraction of castor seed. The physico-chemical characteristics like low cloud point, pour point, oxidation stability and lubricity of castor oil alkyl esters was determined, which suggests that methyl and ethyl esters of castor oil could be used as a sustainable biodiesel whereas higher alkyl esters such as propyl and butyl esters are suitable for biolubricant.