Catalytic Gas-Phase Production of Lactide from Renewable Alkyl Lactates

Rik De Clercq; Michiel Dusselier; Ekaterina Makshina; Bert F Sels

doi:10.1002/anie.201711446

Catalytic Gas-Phase Production of Lactide from Renewable Alkyl Lactates

Angew Chem Int Ed Engl. 2018 Mar 12;57(12):3074-3078. doi: 10.1002/anie.201711446. Epub 2018 Feb 15.

Authors

Rik De Clercq¹, Michiel Dusselier¹, Ekaterina Makshina¹, Bert F Sels¹

Affiliation

¹ Centre for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium.

PMID: 29356294
DOI: 10.1002/anie.201711446

Abstract

A new route to lactide, which is a key building block of the bioplastic polylactic acid, is proposed involving a continuous catalytic gas-phase transesterification of renewable alkyl lactates in a scalable fixed-bed setup. Supported TiO₂ /SiO₂ catalysts are highly selective to lactide, with only minimal lactide racemization. The solvent-free process allows for easy product separation and recycling of unconverted alkyl lactates and recyclable lactyl intermediates. The catalytic activity of TiO₂ /SiO₂ catalysts was strongly correlated to their optical properties by DR UV/Vis spectroscopy. Catalysts with high band-gap energy of the supported TiO₂ phase, indicative of a high surface spreading of isolated Ti centers, show the highest turnover frequency per Ti site.

Keywords: alkyl lactates; lactide; supported catalysts; sustainable chemistry; transesterification.

Publication types

Research Support, Non-U.S. Gov't