ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mass-transfer in pertraction of butyric acid by phosphonium ionic liquids and dodecane

Ján Marták, Štefan Schlosser, and Marek Blahušiak

Department of Chemical and Biochemical Engineering, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovakia

E-mail: stefan.schlosser@stuba.sk

Abstract: Transport of butyric acid (BA) through a supported liquid membrane (SLM) containing phosphonium ionic liquid (IL) Cyphos IL-104 and dodecane occurs by two mechanisms. The first is related to the physical solubility of undissociated acid in dodecane in the form of a monomer or dimer and the second to the reactive extraction of acid by IL. Although the model of pertraction indicates that increasing the mean concentration of acid in the feed, c _F,lmv, increases the participation of pertraction based on the physical solubility; in the tested range of c _F,lmv from 0 kmol m⁻³ to 0.45 kmol m⁻³ it does not play an important role and at the highest c _F,lmv value, less than 10 % of the overall BA transport were achieved. The presence of IL in SLM considerably increases the value of the overall mass transfer coefficient in pertraction at low BA concentrations. However, at c _F,lmv > 0.4 kmol m⁻³ its values are similar for SLMs with and without IL. Compared to lactic acid, the pertraction of BA through the same SLM is about five times faster. Reactive transport of BA is connected with the back transport of water via reverse micelles decomposition and formation on the extraction and stripping interfaces.

Keywords: pertraction – supported liquid membrane – butyric acid – phosphonium ionic liquid – mass-transfer – mechanism

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-011-0069-3

Chemical Papers 65 (5) 608–619 (2011)