- Catalytic upcycling of PVC waste-derived phthalate esters into safe, hydrogenated plasticizers
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Recycling of end-of-life polyvinyl chloride (PVC) calls for solutions to deal with the vast amounts of harmful phthalate plasticizers that have historically been incorporated in PVC. Here, we report on the upcycling of such waste-extracted phthalate esters into analogues of the much safer diisononyl 1,2-cyclohexanedicarboxylate plasticizer (DINCH), via a catalytic one-pot (trans)esterification-hydrogenation process. For most of the virgin phthalates, Ru/Al2O3 is a highly effective hydrogenation catalyst, yielding >99% ring-hydrogenated products under mild reaction conditions (0.1 mol% Ru, 80 °C, 50 bar H2). However, applying this reaction to PVC-extracted phthalates proved problematic, (1) as benzyl phthalates are hydrogenolyzed to benzoic acids that inhibit the Ru-catalyst, and (2) because impurities in the plasticizer extract (PVC, sulfur) further retard the hydrogenation. These complications were solved by coupling the hydrogenation to an in situ (trans)esterification with a higher alcohol, and by pretreating the extract with an activated carbon adsorbent. In this way, a real phthalate extract obtained from post-consumer PVC waste was eventually completely (>99%) hydrogenated to phthalate-free, cycloaliphatic plasticizers. This journal is
- Bals, Sara,De Vos, Dirk E.,Diefenhardt, Thomas,Jain, Noopur,Marquez, Carlos,Schlummer, Martin,Windels, Simon
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supporting information
p. 754 - 766
(2022/02/02)
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- THE SIDE REACTIONS IN THE ESTERIFICATION OF PHTALIC ANHHYDRIDE WITH 2-ETHYLHEXANE-1-OL IN THE PRESENCE OF ORGANOTITANATES
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Using synthetic, chromatographic and spectral methods, we studied the side reactions accompanying the preparation of di-2-ethylhexyl phtalate from phtalic anhydride and 2-ethylhexane-1-ol in the presence of catalytic amounts of tetra-n-butyl titanate.The catalyst proper was titanium(IV) mono-2-ethylhexyl phtalate.The possibility of a simultaneous gas-chromatographic quantitative determination of mono-2-ethylhexyl phtalate, di-2-ethylhexyl phtalate, 2-ethylhexan-1-ol and tetra-n-butyl titanate, reported in literature, has been refuted.In the esterification catalysedby hydrated titanium dioxide homogeneous catalysis by the formed organotitanate was dominating.The dissolving of hydrated titanium dioxide in the esterification of phtalic anhydride with 2-ethylhexane-1-ol was studied polarographically.
- Novrocik, Jan,Novrocikova, Marta,Norek, Jiri,Koruna, Ivan,Ryska, Miroslav
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p. 253 - 266
(2007/10/02)
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