Retraction to: Catalysis Letters (2006) 110(3–4):261–267 https://doi.org/10.1007/s10562-006-0119-6

The Publisher has retracted this article by Passos et al. [1]. Owing to a technical error Passos et al. (2006) [2] was republished in the same journal creating a duplicate publication [1]. The Publisher apologises to the authors and to readers for this error. All authors agree with this retraction.