Transesterification Optimization, Kinetic Parameters, and Engine Emission Profiles of Biodiesel from Ricinus communis Seed Oil

International Journal of Chemistry | Vol. 10, No. 2, February 2019 | pp. 9–16

DOI: 10.46882/2019/IJC/000124

Article Type: Original Research Paper

Title: Transesterification Optimization, Kinetic Parameters, and Engine Emission Profiles of Biodiesel from Ricinus communis Seed Oil

Names of Authors: M. C. Okonkwo¹, T. H. Nguyen²*

Authors’ Affiliations:
¹Department of Industrial Chemistry, Enugu State University of Science and Technology, Enugu, Nigeria.
²Department of Chemical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam.

Abstract: The utilization of non-edible crop lipids as chemical feedstocks for alternative bio-fuel synthesis promotes green energy targets without competing with food supplies. This study investigates the transesterification kinetics and chemical properties of biodiesel synthesized from castor (Ricinus communis) seed oil. Because of an elevated initial free fatty acid content (5.64 mg KOH/g), a two-step acid-base catalyzed transesterification route was deployed. The first step reduced the acid value below 1.0 mg KOH/g using 1.2% v/v sulfuric acid in methanol, followed by a base-catalyzed transesterification with sodium methoxide. Fatty acid methyl ester (FAME) yield was optimized at 94.5% using a 6:1 methanol-to-oil molar ratio, a catalyst concentration of 1.0 wt% NaOH, and a process temperature of 60°C for 90 minutes. Kinetic analysis confirmed that the transesterification process followed pseudo-first-order reaction mechanics with an activation energy of 40.5 kJ/mol. Fuel properties of the prepared biodiesel, including kinematic viscosity (4.38 mm²/s at 40°C), flash point (168°C), and cetane number (52), matched international ASTM D6751 regulatory specifications. Diesel engine tests using a B20 blend showed a 12.4% reduction in hydrocarbon emissions compared to conventional diesel.

Keywords: Ricinus communis; Biodiesel; Transesterification; Reaction kinetics; Activation energy; Kinematic viscosity

Manuscript Timeline: Received: April 10, 2018; Revised: May 22, 2018; Accepted: June 18, 2018; Published: February 06, 2019.

Citation: Okonkwo, M. C., & Nguyen, T. H. (2019). Transesterification Optimization, Kinetic Parameters, and Engine Emission Profiles of Biodiesel from Ricinus communis Seed Oil. International Journal of Chemistry, 10(2), 9–16.

Subscribe to read the full article: https://internationalscholarsjournals.org/subscribe-to-read