Issue 4, 2005

Recovery of amino acids by imidazolium based ionic liquids from aqueous media

Abstract

In this paper, imidazolium based ionic liquids [C4mim][PF6], [C6mim][PF6], [C6mim][BF4] and [C8mim][BF4] were used as alternative solvents for the recovery of some amino acids (L-tryptophan, L-phenylalanine, L-tyrosine, L-leucine and D-valine) from aqueous media. The experimental results shown that logarithm of partition coefficients, log (PIL/W), of the amino acids correlate well with the hydrophobicity of the amino acids, indicating the importance of the hydrophobic effect of amino acids as a driving force for their partition into a particular ionic liquid. The partition coefficients are found to be strongly affected by pH of aqueous phases and the water solubility in ionic liquids. They decrease steeply with increasing pH in the range of pH < pK1, but increase with increasing solubility of water in ionic liquid phases. The higher extraction degree at low pHs has been interpreted by the strong electrostatic interactions between cationic form of the amino acids and anion of the ionic liquids. The importance of anionic nature and the alkyl chain length on the cation of ionic liquids have also been examined. It is noted that ionic liquid with BF4 anion has much higher extraction efficiency for the amino acids than those with PF6 anion because of the stronger effective charge in BF4. It seems likely that there is no correlation between the partition coefficients of the amino acids and the polarity of the ionic liquids. Preliminary results indicated that [C6mim][BF4] and [C8mim][BF4] ionic liquids may be adapted to liquid-liquid recovery process of some amino acids from aqueous media, and L-tryptophan can be effectively separated from fermentation broth in a multiple step process using [C6mim][BF4] as an extractant.

Graphical abstract: Recovery of amino acids by imidazolium based ionic liquids from aqueous media

Article information

Article type
Paper
Submitted
13 Oct 2004
Accepted
03 Feb 2005
First published
18 Feb 2005

Green Chem., 2005,7, 196-202

Recovery of amino acids by imidazolium based ionic liquids from aqueous media

J. Wang, Y. Pei, Y. Zhao and Z. Hu, Green Chem., 2005, 7, 196 DOI: 10.1039/B415842C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements