Improving the Efficiency for the Production of Bis-(2-Hydroxyethyl) Terephtalate (BHET) from the Glycolysis Reaction of Poly(Ethylene Terephtalate) (PET) in a Pressure Reactor

The depolymerization process of PET by glycolysis into BHET monomer is optimized in terms of reaction temperature and time, by carrying out the process under pressure to be faster for reducing the energy required. Almost pure BHET has been obtained by working in a pressure reactor at 3 bar both at 220 and 180 °C after short reaction times, while for longer ones a mixture of oligomers and dimers is obtained. Depending on the potential application required, the obtention of different reaction products is controlled by adjusting reaction temperature and time. The use of a pressure reactor allows work at lower temperatures and shorter reaction times, obtaining almost pure BHET. To the best of our knowledge, except for microwave-assisted procedures, it is the first time in which pure BHET is obtained after such short reaction times, at lower temperatures than those usually employed

Valorization of urban and marine PET waste by optimized chemical recycling

The degradation of two poly(ethylene terephtalate) (PET) samples from urban and marine wastes (PET-u and PET-m, respectively) has been studied by comparing their properties with those of virgin PET (PET-v) and post condensed PET for bottle fabrication (PET-ssp). FTIR spectroscopy, DSC analysis, WCA and MFI results have confirmed that all PET residues were degraded. Therefore, the chemical recycling has been evaluated in order to valorize PET-m and PET-u wastes, analyzing the effect of degradation on the process. Glycolysis of degraded and non-degraded PET samples has been carried out in a pressure reactor at 220C for 30 min. For all the cases almost pure BHET monomer has been obtained: 96.5 and 96.7 % for PET-m and PET-u respectively, values 2 and 13 % higher than those obtained for PET-ssp and PET-v. Obtained results indicate that the initial degradation of PET wastes increases the BHET monomer content in the glycolyzed sample.Financial support from the University of the Basque Country in the frame of GIU18/216 and from the Provincial Council of Gipuzkoa (ItsasMikro project) are gratefully acknowledged. Authors thank the Circular Economy University-Company Classroom (Faculty of Engineering Gipuzkoa, UPV/EHU, Provincial Council of Gipuzkoa) . More-over, we are grateful to the Macrobehaviour-Mesostructure-Nanotechnology SGIker unit of UPV/EHU. Eider Mendiburu Valor thanks Basque Government for PhD grant (PRE_2018_1_0014)

Valorization of marine PET litter: from conventional methods to chemical recycling for the synthesis of novel polyurethanes

241 p. (eusk.) 238 p. (eng.)Lan hau itsasoko poli(tereftalato etileno) hondakinen (PET-m) birziklapenean zentratzen da, hondakin kutsagarri honi bigarren bizitza bat eman ahal izateko. 1. Kapituluan sarrera eta 2. Kapituluan erabilitako material eta metodoen azalpena egiten da. 3. Kapituluan hainbat PET lagin aztertu dira, hala nola PET lehengai gordina eta post-kondentsatua, eta kontsumo osteko hiri-hondakinak eta itsasoko PET hondakinak. Degradazioaren eragina aztertzeko hondakinen karakterizazioa burutu da. 4. Kapituluan, itsasoko PET hondakinak balorizatzeko metodo konbentzionalenak erabili dira: birziklatze termo-mekanikoa eta aprobetxamendu energetikoa. Birziklatzean gerta litezken degradazioak ere aztertu dira. 5. Kapituluan, itsasoko PET hondakinen birziklatze kimikoa aztertu da, oso degradatua dagoen PETaren balorizazio alternatiba onena bezala, PET-m hondakinentzat. Birziklatze kimikoa proposatzeko, glikolisi erreakzioa erreaktore itxi batean optimizatu da, errendimendu handia lortuz erreakzio-denbora oso baxuan eta produktua karakterizatu da. 6. Kapituluan, biooinarritutako eta birziklatutako PU termoplastikoen sintesia egin da, eta, horretarako, makrodiol bioonarritu bat, 5. Kapituluan lortutako BHET birziklatua eta HDI erabili dira. Era berean, sintetizatutako TPUen karakterizazioa egin da, BHET komertziala erabiliz sintetizatutako TPUekin alderatuz. Azkenik, sintetizatutako TPUen birziklagarritasun termo-mekanikoa zein kimikoa aztertu da. 7. Kapituluan, biooinarritutako eta birziklatutako PU termoegonkorrak sintetizatu dira. Horretarako errizino-olio jatorriko poliol baten, BHET birziklatuaren eta pMDIren erlazio desberdinak erabili dira. Helburua osagai berriztagarri/birziklatuen ehuneko handi bat duten PU termoegonkorrak sintetizatzea izan da, itsasoko PET hondakinetatik lortutako BHET birziklatuari balio erantsia emanez. Era berean, sintetizatuko PU termoegonkorren karakterizazioa egin da, haien birziklagarritasun kimikoaren azterketarekin batera. 8. Kapituluan, tesi honen prozesu batzuen analisi kuantitatiboa egin da, bizi-zikloaren azterketa eginez. BHET berreskuratzeko itsasoko PET hondakinen birziklatze kimikoaren eragina aztertu da Gainera, 6. Kapituluan sintetizatutako TPUen inpaktuak aztertu dira, BHET komertzialarekin sintetizatutako TPUekin eta oinarri petrokimikoko TPU batekin alderatuz. 9. Kapituluan, orokorrak, lortu diren argitalpenak eta etorkizunerako proposatzen diren lan-ildoak aurkezten dira

Improving the Efficiency for the Production of Bis-(2-Hydroxyethyl) Terephtalate (BHET) from the Glycolysis Reaction of Poly(Ethylene Terephtalate) (PET) in a Pressure Reactor

The depolymerization process of PET by glycolysis into BHET monomer is optimized in terms of reaction temperature and time, by carrying out the process under pressure to be faster for reducing the energy required. Almost pure BHET has been obtained by working in a pressure reactor at 3 bar both at 220 and 180 °C after short reaction times, while for longer ones a mixture of oligomers and dimers is obtained. Depending on the potential application required, the obtention of different reaction products is controlled by adjusting reaction temperature and time. The use of a pressure reactor allows work at lower temperatures and shorter reaction times, obtaining almost pure BHET. To the best of our knowledge, except for microwave-assisted procedures, it is the first time in which pure BHET is obtained after such short reaction times, at lower temperatures than those usually employed