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

Application of an enzymatic cascade reaction for the synthesis of the emeraldine salt form of polyaniline

Minoru Kurisu, Reinhard Kissner, Masayuki Imai, and Peter Walde

Department of Physics, Graduate School of Science, Tohoku University, Sendai, Japan

E-mail: peter.walde@mat.ethz.ch

Received: 15 January 2021  Accepted: 23 March 2021

Abstract:

The synthesis of the emeraldine salt form of polyaniline (PANI-ES) from aniline with Aspergillus sp. glucose oxidase (GOD), d-glucose, dissolved O₂, and horseradish peroxidase isoenzyme C (HRPC) in the presence of large unilamellar vesicles of AOT (sodium bis-(2-ethylhexyl)sulfosuccinate) as templates at pH = 4.3 and T ~ 25 °C was investigated in a systematic way. In this cascade reaction mixture, the oxidation of aniline is catalyzed by HRPC with H₂O₂ that is formed in situ as byproduct of the GOD-catalyzed oxidation of d-glucose with O₂. Under the elaborated experimental conditions which we considered ideal, the formation of PANI-ES products is evident, as judged by UV/Vis/NIR and EPR measurements. Comparison was made with a reference reaction, which was run under similar conditions with added H₂O₂ instead of GOD and d-glucose. Although the reference reaction was found to be superior, with the cascade reaction, PANI-ES products can still be obtained with high aniline conversion (> 90%) within 24 h as stable dark green PANI-ES/AOT vesicle dispersion. Our results show that the in situ formation of H₂O₂ does not prevent the inactivation of HRPC known to occur in the reference reaction. Moreover, the GOD used in the cascade reaction is inactivated as well by polymerization intermediates.

Keywords: Aniline; Glucose oxidase; Horseradish peroxidase; Template; Polyaniline; Vesicles

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01620-z

Chemical Papers 75 (10) 5071–5085 (2021)