A combined spectroscopic and theoretical study of dibutyltin diacetate and dilaurate in supercritical CO2

Abstract : Two organotin catalysts, namely, dibutyltin dilaurate (DBTDL) and dibutyltin diacetate (DBTDA), commonly used in the synthesis of polyurethanes, have been investigated combining vibrational spectroscopic measurements with molecular modeling. The structure and vibrational spectra of the DBTDA molecule have been simulated using density functional theory. Thus, because of the Sn center dot center dot center dot O interactions, the lowest energy conformer reveals an asymmetrically chelated structure of the acetate groups with a C-2u symmetry. The experimental IR spectra of DBTDA and DBTDL diluted in carbon tetrachloride and in supercritical CO2 show unambiguously that these molecules adopt the asymmetrically chelated conformation in the solvent. A new attribution of the main peaks constituting the respective IR spectra of the catalysts could be carried out. Finally, from the IR spectra of the two catalysts diluted in supercritical CO2 reported as a function of time, it was found that both molecules react slightly with CO2. However, their spectrum remains unchanged at the earliest stage of the polymerization, indicating that these molecules preserve a catalytic activity similar to that noted in conventional organic solvent.
Document type :
Journal articles
Complete list of metadatas

https://hal.archives-ouvertes.fr/hal-00354743
Contributor : Dominique Richard <>
Submitted on : Tuesday, January 20, 2009 - 5:14:15 PM
Last modification on : Thursday, September 6, 2018 - 4:00:03 PM

Identifiers

Collections

Citation

Benjamin Renault, Eric Cloutet, Henri Cramail, Yacine Hannachi, Thierry Tassaing. A combined spectroscopic and theoretical study of dibutyltin diacetate and dilaurate in supercritical CO2. Journal of Physical Chemistry A, American Chemical Society, 2008, 112 (36), pp.8379-8386. ⟨10.1021/jp8004822⟩. ⟨hal-00354743⟩

Share

Metrics

Record views

173