{"id":{"repo_id":"qu-belfast","oai_identifier":"oai:pure.qub.ac.uk/portal:studenttheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f"},"canonical_url":"https://search.dev.ndltd.org/etd/qu-belfast/oai:pure.qub.ac.uk/portal:studenttheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f","repository":{"repo_id":"qu-belfast","name":"Queen's University Belfast","base_url":"https://pureadmin.qub.ac.uk/ws/oai"},"display":{"title":"Chemical recycle of polyester waste using novel zwitterionic catalysts","abstract":"Waste poly (ethylene terephthalate) (PET) from drink bottles wasdepolymerized using novel zwitterionic imidazolium-2-carboxylate salts ascatalysts (or catalyst-precursors) in the presence of ethylene glycol viaglycolysis to give bis(hydroxyethyl)terephthalate (BHET). The influence ofreaction temperature, glycolysis time, ethylene glycol:PET ratios, and theamount of the zwitterionic imidazolium-2-carboxylate catalysts used on theconversion of PET, isolated yield of BHET, and the selectivity of BHET in theglycolysis of PET were investigated.<br/><br/> The results demonstrate that 1,3-dimethylimidazolium-2-carboxylate can bean effective basic catalyst for PET glycolysis, with PET depolymerization of upto 100% observed. BHET was isolated from the reaction mixture with yields ofup to 61.0% under the optimum reaction conditions using 0.15 g catalyst to 1.0g PET in the presence of 10.0 g ethylene glycol (0.15:1:10 mass ratio) at 185oCin 1 h. This is the first time that 1,3-dialkyl-imidazolium-2-carboxylates havebeen reported to be catalysts for glycolysis of PET and, compared to 1,3-dialkylimidazolium acetate ionic liquids, were more effective as catalyst in theglycolysis. The purified monomer was characterized by the nuclear magneticresonance (NMR), mass spectrometry, and high performance liquidchromatography (HPLC). <br/><br/><br/>","abstract_html":"Waste poly (ethylene terephthalate) (PET) from drink bottles wasdepolymerized using novel zwitterionic imidazolium-2-carboxylate salts ascatalysts (or catalyst-precursors) in the presence of ethylene glycol viaglycolysis to give bis(hydroxyethyl)terephthalate (BHET). The influence ofreaction temperature, glycolysis time, ethylene glycol:PET ratios, and theamount of the zwitterionic imidazolium-2-carboxylate catalysts used on theconversion of PET, isolated yield of BHET, and the selectivity of BHET in theglycolysis of PET were investigated.&lt;br/&gt;&lt;br/&gt; The results demonstrate that 1,3-dimethylimidazolium-2-carboxylate can bean effective basic catalyst for PET glycolysis, with PET depolymerization of upto 100% observed. BHET was isolated from the reaction mixture with yields ofup to 61.0% under the optimum reaction conditions using 0.15 g catalyst to 1.0g PET in the presence of 10.0 g ethylene glycol (0.15:1:10 mass ratio) at 185oCin 1 h. This is the first time that 1,3-dialkyl-imidazolium-2-carboxylates havebeen reported to be catalysts for glycolysis of PET and, compared to 1,3-dialkylimidazolium acetate ionic liquids, were more effective as catalyst in theglycolysis. The purified monomer was characterized by the nuclear magneticresonance (NMR), mass spectrometry, and high performance liquidchromatography (HPLC). &lt;br/&gt;&lt;br/&gt;&lt;br/&gt;","abstract_has_math":false,"creators":["Wang, Lei"],"institution":"Queen's University Belfast","degree_name":"Master of Philosophy","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Holbrey, John","Swadzba-Kwasny, Malgorzata"],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019","date_published":"2019","updated_at":"2026-07-24T03:54:59Z","subjects":["Poly (ethylene terephthalate) (PET)","bis (hydroxyethyl) terephthalate (BHET)","glycolysis","carbene","zwitterionic catalyst","imidazolium2-carboxylate (NHC-CO2)"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.qub.ac.uk/portal:studenttheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f"],"render_values":[{"text":"oai:pure.qub.ac.uk/portal:studenttheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f","href":null,"code":true}]}]},"links":{"outbound_url":"https://pure.qub.ac.uk/en/studentTheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Holbrey, John","Swadzba-Kwasny, Malgorzata"]},{"key":"dc:creator","label":"Author","values":["Wang, Lei"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019"]},{"key":"dc:date.issued","label":"Date","values":["2019"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Chemistry and Chemical Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Queen's University Belfast"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://pure.qub.ac.uk/en/studentTheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters Thesis"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Master of Philosophy"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Poly (ethylene terephthalate) (PET)","bis (hydroxyethyl) terephthalate (BHET)","glycolysis","carbene","zwitterionic catalyst","imidazolium2-carboxylate (NHC-CO2)"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.qub.ac.uk/portal:studenttheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f","https://pure.qub.ac.uk/en/studentTheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://pure.qub.ac.uk/files/163385717/final_mphil_thesis_lei.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Waste poly (ethylene terephthalate) (PET) from drink bottles wasdepolymerized using novel zwitterionic imidazolium-2-carboxylate salts ascatalysts (or catalyst-precursors) in the presence of ethylene glycol viaglycolysis to give bis(hydroxyethyl)terephthalate (BHET). The influence ofreaction temperature, glycolysis time, ethylene glycol:PET ratios, and theamount of the zwitterionic imidazolium-2-carboxylate catalysts used on theconversion of PET, isolated yield of BHET, and the selectivity of BHET in theglycolysis of PET were investigated.<br/><br/> The results demonstrate that 1,3-dimethylimidazolium-2-carboxylate can bean effective basic catalyst for PET glycolysis, with PET depolymerization of upto 100% observed. BHET was isolated from the reaction mixture with yields ofup to 61.0% under the optimum reaction conditions using 0.15 g catalyst to 1.0g PET in the presence of 10.0 g ethylene glycol (0.15:1:10 mass ratio) at 185oCin 1 h. This is the first time that 1,3-dialkyl-imidazolium-2-carboxylates havebeen reported to be catalysts for glycolysis of PET and, compared to 1,3-dialkylimidazolium acetate ionic liquids, were more effective as catalyst in theglycolysis. The purified monomer was characterized by the nuclear magneticresonance (NMR), mass spectrometry, and high performance liquidchromatography (HPLC). <br/><br/><br/>"]},{"key":"dc:title","label":"Title","values":["Chemical recycle of polyester waste using novel zwitterionic catalysts"]}]}],"canonical_facts":{"dc:contributor.advisor":["Holbrey, John","Swadzba-Kwasny, Malgorzata"],"dc:creator":["Wang, Lei"],"dc:date":["2019"],"dc:date.issued":["2019"],"dc:description.abstract":["Waste poly (ethylene terephthalate) (PET) from drink bottles wasdepolymerized using novel zwitterionic imidazolium-2-carboxylate salts ascatalysts (or catalyst-precursors) in the presence of ethylene glycol viaglycolysis to give bis(hydroxyethyl)terephthalate (BHET). The influence ofreaction temperature, glycolysis time, ethylene glycol:PET ratios, and theamount of the zwitterionic imidazolium-2-carboxylate catalysts used on theconversion of PET, isolated yield of BHET, and the selectivity of BHET in theglycolysis of PET were investigated.<br/><br/> The results demonstrate that 1,3-dimethylimidazolium-2-carboxylate can bean effective basic catalyst for PET glycolysis, with PET depolymerization of upto 100% observed. BHET was isolated from the reaction mixture with yields ofup to 61.0% under the optimum reaction conditions using 0.15 g catalyst to 1.0g PET in the presence of 10.0 g ethylene glycol (0.15:1:10 mass ratio) at 185oCin 1 h. This is the first time that 1,3-dialkyl-imidazolium-2-carboxylates havebeen reported to be catalysts for glycolysis of PET and, compared to 1,3-dialkylimidazolium acetate ionic liquids, were more effective as catalyst in theglycolysis. The purified monomer was characterized by the nuclear magneticresonance (NMR), mass spectrometry, and high performance liquidchromatography (HPLC). <br/><br/><br/>"],"dc:identifier":["oai:pure.qub.ac.uk/portal:studenttheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f","https://pure.qub.ac.uk/en/studentTheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f"],"dc:identifier.uri":["https://pure.qub.ac.uk/files/163385717/final_mphil_thesis_lei.pdf"],"dc:language":["eng"],"dc:publisher.department":["School of Chemistry and Chemical Engineering"],"dc:publisher.institution":["Queen's University Belfast"],"dc:relation.isreferencedby":["https://pure.qub.ac.uk/en/studentTheses/a8daade3-74cb-4799-9c25-08e5ca77cd3f"],"dc:subject":["Poly (ethylene terephthalate) (PET)","bis (hydroxyethyl) terephthalate (BHET)","glycolysis","carbene","zwitterionic catalyst","imidazolium2-carboxylate (NHC-CO2)"],"dc:title":["Chemical recycle of polyester waste using novel zwitterionic catalysts"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Masters Thesis"],"dc:type.qualificationname":["Master of Philosophy"]},"updated_at":"2026-07-24T03:54:59Z"}