title: Lactide Synthesis and Chirality Control for Polylactic acid Production.
abstract: Polylactic acid (PLA) is a very promising biodegradable, renewable, and biocompatible polymer. Aside from its production, its application field is also increasing, with use not only in commodity applications but also as durables and in biomedicine. In the current PLA production scheme, the most expensive part is not the polymerization itself but obtaining the building blocks lactic acid (LA) and lactide, the actual cyclic monomer for polymerization. Although the synthesis of LA and the polymerization have been studied systematically, reports of lactide synthesis are scarce. Most lactide synthesis methods are described in patent literature, and current energy-intensive, aselective industrial processes are based on archaic scientific literature. This Review, therefore, highlights new methods with a technical comparison and description of the different approaches. Water-removal methodologies are compared, as this is a crucial factor in PLA production. Apart from the synthesis of lactide, this Review also emphasizes the use of chemically produced racemic lactic acid (esters) as a starting point in the PLA production scheme. Stereochemically tailored PLA can be produced according to such a strategy, giving access to various polymer properties.
authors.affiliation: Center for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Van Wouwe
authors.affiliation: Center for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium. michiel.dusselier@biw.kuleuven.be.
authors.forename: Michiel
authors.initials: M
authors.lastname: Dusselier
authors.affiliation: Center for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium.
authors.forename: Evelien
authors.initials: E
authors.lastname: Vanleeuw
authors.affiliation: Center for Surface Chemistry and Catalysis, KU Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium. bert.sels@biw.kuleuven.be.
authors.forename: Bert
authors.initials: B
authors.lastname: Sels
mesh_terms: D004146:Dioxanes / Q000138:chemical synthesis* / Q000737:chemistry; D019344:Lactic Acid / Q000096:biosynthesis / Q000737:chemistry; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry; D058105:Polymerization; D013237:Stereoisomerism
chemical_list: D004146:Dioxanes; D011091:Polyesters; D019344:Lactic Acid; C033616:poly(lactide); C091880:dilactide
keywords: chirality; enzymes; polylactic acid; renewable polymers; zeolites