1-Butyl-3-methylimidazolium hydrogen sulfate catalyzed in-situ transesterification of Nannochloropsis to fatty acid methyl esters

Yingqiang Sun, Peter Cooke, Harvind K. Reddy, Tapaswy Muppaneni, Jun Wang, Zheling Zeng, Shuguang Deng

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


1-Butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO4]) is used as a solvent and an acid catalyst for in-situ extractive transesterification of wet Nannochloropsis with methanol. The reaction is supposed to be a five-step process: (1) wet algae cell wall dissolves in ionic liquid at reaction temperatures; (2) hydrogen ions and sulfate ions release from the ionization of HSO4. The hydrogen ions (H+) act as catalysts for accelerating the reactive extraction of triglyceride from wet Nannochloropsis; (3) hydrogen ions and methanol molecules transfer from bulk to active site of cells without passing through cell wall that is dissolved by ionic liquid; (4) in-situ transesterification of lipid (mainly triglycerides) with methanol; and (5) products transfer from inside of algae cells to outside of cells. The crude biodiesel yield of [Bmim][HSO4] catalyzed in-situ transesterification is about 95.28% at reaction temperature of 200 °C, reaction time of 30 min, mass ratio of [Bmim][HSO4] to wet Nannochloropsis of 0.9:1, and a mass ratio of methanol to wet algae of 3:1. It decreases to 81.23% after [Bmim][HSO4] is recycled for 4 times, which indicates that [Bmim][HSO4] catalyzed in-situ transesterification is an economic approach for biodiesel production from wet algae.

Original languageEnglish (US)
Pages (from-to)213-220
Number of pages8
JournalEnergy Conversion and Management
StatePublished - Jan 15 2017


  • Biodiesel
  • Extraction
  • In-situ transesterification
  • Ionic liquid
  • Wet algae

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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