- Transforming polylactide into value-added materials
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The production of chemical building blocks and polymer precursors from biorenewable and sustainable resources is an attractive method to bypass traditional fossil fuel derived materials. Accordingly, we report the organocatalytic recycling of postconsumer polylactide (PLA) into value-added small molecules. This strategy, using the highly active transesterification catalyst triazabicyclodecene, is shown to completely depolymerize PLA in the presence of various alcohols into valuable lactate esters. Using previously used PLA packaging material, the depolymerization is complete in minutes at room temperature and fully retains the stereochemistry of the lactate species. Further, the modularity and utility of this methodology with respect to polyester substrate is detailed by using a variety of functional alcohols to depolymerize both PLA and polyglycolide, with the corresponding ester small-molecules being used to make new polymeric materials. The opportunities to transform waste streams into value-added chemicals and new materials through simple and versatile chemistry hold significant potential to extend the lifecycle of renewable chemical feedstocks.
- Leibfarth, Frank A.,Moreno, Nicholas,Hawker, Alex P.,Shand, Justin D.
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Read Online
- Conversion of lactides into ethyl lactates and value-added products
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This Letter describes an attractive and efficient method for Mg(OR)2-mediated lactide alcoholysis. The catalysts were generated in situ from di-n-butylmagnesium and ROH to prevent aggregation of Mg(OR)2. The reaction of ROH [R = Me,
- Bykowski, Dominik,Grala, Agnieszka,Sobota, Piotr
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supporting information
p. 5286 - 5289
(2015/01/16)
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- Chemoselective alcoholysis of lactide mediated by a magnesium catalyst: An efficient route to alkyl lactyllactate
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Alkyl-(S,S)-O-lactyllactate was prepared by chemoselective alcoholysis of lactide LA mediated by a magnesium catalyst. When ROH reacted with LA it yielded the ring-opened product R-(S,S)-O-lactyllactate exclusively, which remained intact as long as LA was present in the reaction mixture. Consumption of LA caused the reaction to proceed further giving R-(S)-lactate.
- Grala, Agnieszka,Ejfler, Jolanta,Jerzykiewicz, Lucjan B.,Sobota, Piotr
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supporting information; scheme or table
p. 4042 - 4044
(2011/06/18)
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- Synthesis of alkyl (R)-lactates and alkyl (S,S)-O-lactyllactates by alcoholysis of rac-lactide using Novozym 435
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Enzymatic alcoholysis of rac-lactide for kinetic resolution was carried out in organic solvents. Effects of organic solvent, reaction temperature, and alcohol as a nucleophile were also investigated in Novozym 435-catalyzed alcoholysis of rac-lactide. Both alkyl (R)-lactate and alkyl (S,S)-O-lactyllactate were simultaneously obtained in high yields (>45%) and high enantiopurities (>97% ee) through Novozym 435-catalyzed ring-opening of rac-lactide and subsequent enantioselective alcoholysis of the resultant alkyl O-lactyllactate.
- Jeon, Nan Young,Ko, Sung-Jin,Won, Keehoon,Kang, Han-Young,Kim, Bum Tae,Lee, Yeon Soo,Lee, Hyuk
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p. 6517 - 6520
(2007/10/03)
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