Rotational studies of adducts between carboxylic acids and tertiary alcohols: Formic acid - tert-butyl alcohol

Weixing Li; Lorenzo Spada; Luca Evangelisti; Walther Caminati

doi:10.1016/j.saa.2021.119621

Rotational studies of adducts between carboxylic acids and tertiary alcohols: Formic acid - tert-butyl alcohol

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Jun 5:254:119621. doi: 10.1016/j.saa.2021.119621. Epub 2021 Feb 26.

Authors

Weixing Li¹, Lorenzo Spada¹, Luca Evangelisti², Walther Caminati³

Affiliations

¹ Dipartimento di Chimica "Giacomo Ciamician" dell'Università, Via Selmi 2, I-40126 Bologna, Italy.
² Dipartimento di Chimica "Giacomo Ciamician" dell'Università, Via Selmi 2, I-40126 Bologna, Italy. Electronic address: luca.evangelisti6@unibo.it.
³ Dipartimento di Chimica "Giacomo Ciamician" dell'Università, Via Selmi 2, I-40126 Bologna, Italy. Electronic address: walther.caminati@unibo.it.

PMID: 33743306
DOI: 10.1016/j.saa.2021.119621

Abstract

The rotational spectra of the parent and eight isotopologues of the 1:1 complex formic acid - tert-butyl alcohol (FA-TBA) have been measured by pulsed jet Fourier transform microwave spectroscopy. The spectra have been observed in the supersonic expansion of a mixture of FA and TBA in Helium, differently with respect to the mixtures of FA with primary and secondary alcohols, which undergo the esterification reaction upon supersonic expansion. In the complex, the two subunits are linked to each other by two different O-H···O hydrogen bonds (HB) in which FA and TBA are alternate their roles of bond acceptor and donor. Upon H → D substitution of the corresponding O-H···O HB, a small Ubbelohde effect is observed.

Keywords: Hydrogen bond; Molecular complexes; Rotational spectroscopy; Ubbelohde effect.