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Catalytic Gas‐Phase Production of Lactide from Renewable Alkyl Lactates
Author(s) -
De Clercq Rik,
Dusselier Michiel,
Makshina Ekaterina,
Sels Bert F.
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201711446
Subject(s) - catalysis , alkyl , racemization , transesterification , lactide , polylactic acid , materials science , solvent , phase (matter) , chemistry , chemical engineering , organic chemistry , copolymer , polymer , engineering
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 TiO 2 /SiO 2 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 TiO 2 /SiO 2 catalysts was strongly correlated to their optical properties by DR UV/Vis spectroscopy. Catalysts with high band‐gap energy of the supported TiO 2 phase, indicative of a high surface spreading of isolated Ti centers, show the highest turnover frequency per Ti site.