Naphthenic acid extraction and speciation from Doba crude oil using carbonate-based ionic liquids. (15th April 2015)

• Record Type: Journal Article
• Authors: Anderson, K.; Atkins, M.P.; Goodrich, P.; Hardacre, C.; Hussain, A.S.; Pilus, R.; Rooney, D.W.
• Is Part Of: Fuel. Volume 146(2015)
• Page Start: 60
• Page End: 68
• Publication Date: 2015-04-15
• Subjects: Naphthenic acid -- Methylcarbonate ionic liquid -- Extraction -- Neutralisation -- Regeneration -- Recycle; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2015.01.015
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Carbonate-based ionic liquids can be used to remove naphthenic acids from crude oil. The reaction mechanism involves the formation of an ionic liquid-naphthenic acid complex. The complex can be reacted with carbonic acid to reform the ionic liquid. Recycling of the ionic liquid has been demonstrated. Abstract: A number of tetraalkylammonium methylcarbonate and hydrogencarbonate based ionic liquids are shown to be capable of reacting with the naphthenic acids contained in Doba crude oil via a neutralisation reaction. Spectral studies show that the ionic liquids neutralisation mechanism involves the formation of an ionic liquid-naphthenate complex, liberating methanol and carbon dioxide. Extraction of the neutralised complex into a separate methanol phase and subsequent regeneration using aqueous carbonic acid results in ∼70% of the ionic liquid being recovered for recycle. Isolation of the naphthenic acids shows that these make up to 0.85 wt% of the crude oil. Speciation of the naphthenic acids shows a mixture of monocyclic, through to tetracyclic structures with carbon numbers in the range C12 –C40 .