Synthesis and characterization of CuO/C catalyst for the esterification of free fatty acid in rubber seed oil

Huei Ruey Ong, Maksudur R. Khan, M. N.K. Chowdhury, Abu Yousuf, Chin Kui Cheng

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Plant oils or animal fats that contain high free fatty acid (FFA) are not preferred for base catalyzed biodiesel production. Pre-esterification is widely used to reduce the FFA content of the oil for avoiding saponification and associated purification cost. In the present study, carbon supported copper oxide (CuO/C) catalyst was prepared for the esterification of FFA in the rubber seed oil (RSO) which was extracted from the fresh seed by soxhlet extractor using hexane as a solvent. Copper nanoparticles were synthesized by sol-gel method and the nanoparticles were impregnated into the pore network of the carbon support. The copper impregnated activated carbon powder was calcined at 400 C in a furnace for 6 h, leading to the formation of CuO/C. The catalyst was characterized by using Brunauer Emmett Teller, X-ray photoelectron spectroscopy, Energy-dispersive X-ray spectroscopy and Thermogravimetric analysis. Moreover, Hammett indicator method was used to determine the acidity of the catalyst. The effects of reaction temperature, methanol/FFA molar ratio, catalyst concentration on the FFA conversion were also studied. Based on the experimental results, methanol to FFA ratio of 10:1, catalyst dose 8 wt%, reaction time of 6 h and temperature 65 C were found as the optimum for the esterification reaction. Therefore, the developed catalyst could be effectively used for the esterification of FFA in plant oil.

Original languageBritish English
Pages (from-to)195-201
Number of pages7
StatePublished - 15 Mar 2014


  • Biodiesel
  • Copper sol
  • Esterification
  • Free fatty acids
  • Rubber seed oil


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