Polietilen Tereftalatoaren (PET) birziklapen kimikoa hidrolisiaren bidez

Polietilen tereftalato birziklatuaren (rPET) eskaera handiak ingurumenaren gaineko sentsibilizazioak eta legediak bultzatuta, kontsumitu osteko PET plastiko-hondakinen sorkuntza handiarekin batera, birziklatze-prozesu eraginkorren premia ekarri du. Birziklapen-teknologia klasikoak, birziklapen mekanikoa adibidez, ez dira eraginkorrak birziklatzen zailak diren edo birziklatzen ez diren plastikoen kasuan; hau da, geruza anitzekoak diren eta oso kutsatuta dauden hondakinen kasuan. Teknologia hauek ziklo-kopuru mugatua dute, eta despolimerizazio kimikoa, berriz, gai da jatorrizko PETetik hasierako ekoizpeneko lehengaiak ekoizteko. Testuinguru honetan, polietilen tereftalatoaren (PET) hidrolisia PET-hondakinen despolimerizaziorako estrategia jasangarria da, rPET-a birpolimerizatzeko abiapuntu gisa erabil daitekeena eta, beste despolimerizazio teknologiak ez bezala, oso kutsatuta dauden kontsumo osteko PET-hondakinen elikadurak onartzen dituena. Lan honek PET-solbolisiaren egungo egoera aztertzen du, eta bereziki PET-hidrolisiarena, bai laborategi mailan bai industria eskalan, eta haren garapenaren alderdirik garrantzitsuenak zehazten ditu.; The high demand for recycled polyethylene terephthalate (rPET) driven by environmental awareness and legislation, together with the large increase in post-consumer PET plastic waste generation, has resulted in an urgent need for efficient recycling processes. Classical recycling technologies, such as mechanical recycling, are ineffective for those materials which show difficulties to be recycled or non-recycled plastics such as multilayer and highly contaminated waste. These technologies are only applied for a limited number of cycles, whereas chemical depolymerization produces raw materials from original PET to those of its initial production. In this context, polyethylene terephthalate (PET) hydrolysis is a sustainable strategy for depolymerization of PET waste that can be used as a starting element for repolymerization to rPET and that, unlike the other depolymerization technologies, tolerates highly contaminated post-consumer PET waste feeds. This work analyzes the current situation of PET solvolysis, and especially PET hydrolysis, both at laboratory and industrial scale, in which the most relevant aspects of its development are detailed

Main Routes of Production of High-Value-Added 2,5-Furandincarboxylic Acid Using Heterogeneous Catalytic Systems

The production of polymers from lignocellulosic biomass is currently one of the challenges to minimizing dependence on fossil fuels such as oil. The cellulosic fraction of this feedstock can be transformed into simple sugars such as glucose or fructose. These sugars can be further converted into 2,5-furandicarboxylic acid (FDCA), a precursor of polyethylene furanoate (PEF). The dehydration of sugars to 5-hydroxymethylfurfural (HMF), a platform molecule to obtain products of interest, has been extensively studied. In addition, the oxidation of this platform molecule to FDCA has been widely investigated. However, a study of the direct or one-step production of FDCA from sugars is needed. This review provides a general overview of the recent research on the catalytic systems for the direct production of FDCA from sugars. Ideally, a single-stage system should be employed. The investigations carried out in a one-step process are first detailed. Different strategies have been tested, such as the physical separation of two phases, where dehydration and oxidation took place separately. In this case, an efficient transfer of HMF is needed. To avoid HMF transfer limitations, other authors focused on the investigation of the one-pot transformation of HMF without physical separation. The major requirement of these processes is to achieve catalytic systems functional for both dehydration and oxidation reactions. Therefore, other investigations focused on the study of two-step integrated systems are also analyzed in this review.This research was funded by the University of the Basque Country (UPV/EHU), Basque Government grant number IT1554-22, and the Spanish Ministry of Economy, Industry and Competitiveness grant number MCIN/AEI/PID2021-122736OB-C43

Chemical recycling of monolayer PET tray waste by alkaline hydrolysis

The high demand for recycled polyethylene terephthalate (rPET) driven by an increase in environmental awareness, the application of more restrictive environmental legislations, together with the large increase in the generation of post-consumer PET plastic waste, has resulted in an urgent need for efficient recycling processes. In this work, alkaline hydrolysis is presented as a promising chemical recycling alternative for PET tray waste. PET depolymerization reactions were carried out under mild conditions (80–100 ºC and atmospheric pressure) using tributylhexadecylphosphonium bromide quaternary salt (TBHDPB) as catalyst. Several operating variables were studied based on PET conversion and terephthalic acid (TPA) yield criteria: (i) catalyst mass ratio of TBHDPB to PET (0–0.2); (ii) particle size (0.5–10 mm); (iii) stirring rate (350–700 rpm); and, (iv) temperature (80–100 ◦C). A good compromise between PET conversion (99.9%) and TPA yield (93.5%) was established after 4 h of reaction, under the following operating conditions: TBHDPB:PET catalyst ratio, 0.2; 100 ◦C; particle size, 1–1.4 mm; and, stirring rate, 525 rpm. In addition, the experimental kinetic data correctly fits to the proposed shrinking core model. Activation energy values of 60 and 57.4 kJ mol-1 were established for the non-catalyzed and catalyzed reactions, respectively, which implies that TBHDPB catalyst does not apparently modify the reaction mechanism.Basque Government by its ELKARTEK 2020 Program (NEOPLAST Project, Reference KK-2020/00107), CDTI (Centro para el Desarrollo Tecnológico Industrial) (OSIRIS Project, CER-20211009)

Hidrokarburo likidoen ekoizpena etilenoaren oligomerizazioaren bitartez

Ethylene is the most demanded light olefin within petrochemical industry, with an increasing annual rate of 3,4% on its demand. Due to the availability of natural gas, ethane’s price has shown a drastic decrease worldwide and, therefore, ethane steam cracking (SC) units are beind boosted within refineries, where ethylene is the main product. This situation has led to an excess of ethylene production, while the deficit on propylene production has increased. Therefore, the valorization of ethylene by oligomerization brings the opportunity to obtain high-added valued products, such as, higher olefins, transportation fuels (gasoline, jet fuel and diesel) and/or aromatics; which has increased the interest in both refiner-ies and petrochemical industries. Appart from facing the excess of ethylene production, the ethylene used in the oligomerization process, can be produced from more sustainable sources (i.e. by CO2 valorization). Hence, oligomerization products, particularly fuels, will be free of sulfur and heteroatoms, and thus, they will show a lower level of toxicity as well as a lower environmental impact in comparison to those derived from fossil fuels. In this work, the main applications of ethylene and the main technologies for ethylene production (conventional and more sustainable ones) are firstly analyzed. Then, ethylene oligomerization technologies which are available in industry are described, where different types of catalysts, operating conditions (temperature and pressure) and the reaction mechanism are explained. Finally, the main facts that relate ethylene oligomerization to Sustainable Development Goals (SDGs) are analyzed.; Etilenoa industria petrokimikoko olefina arinen merkatuan liderra da, eta haren eskaria urtean % 3,4 igo-tzen da. Gas naturalaren eskuragarritasuna dela eta, etanoaren prezioak beherakada nabarmena izan du mundu-mailan eta horrek findegietan etanoaren ur-lurrun bidezko cracking termiko (SC) izeneko prozesuaren erabilera areagotu du, non eti-lenoa ekoizten den nagusiki. Horrek findegietan etilenoaren gaindikina izatea eragin du, eta areagotu egin du propilenoaren ekoizpenean dagoen defizita. Hori horrela, etilenoa oligomerizazioaren bitartez balorizatzeak balio erantsiko produktuak ekoiztea ahalbidetzen du, hala nola olefina astunak, erregaiak (gasolina, jet fuela eta diesela) edota aromatikoak; beraz, interesa piztu du gaur egungo findegietan zein industria petrokimikoetan. Izan ere, etilenoaren gaindikinari aurre egiteaz gain, oligomerizazioan erabilitako etilenoa iturri jasangarrietatik baldin badator, esate baterako CO2-aren balorizaziotik, lortutako oligomerizazio-produktuek, bereziki erregaiek, ez dute sufrerik izango, ezta heteroatomorik ere; beraz, toxikotasun-maila askoz baxuagoa izango dute, eta jatorri fosiletik lortutako erregaiek baino inpaktu txikiagoa ingurumenean. Artikulu honetan, lehendabizi etilenoaren erabilerak, ohiko teknologiak eta teknologia berriztagarriagoak laburki azaldu dira. Jarraian, etile-noaren oligomerizaziorako industrian ezarrita dauden teknologiak deskribatu dira, katalizatzaile motak, operazio-baldintzak(tenperatura eta presioa) eta erreakzio-mekanismoa aztertuz. Azkenik, etilenoaren oligomerizazioak eta garapen jasangarrirako helburuen (GJHen) arteko harremana erlazionatzen duten gakoak laburbildu dira

Viviendas equipadas para estudiantes en la c/Sor Francisca Armendáriz (Cartagena) : Microreordenación del casco histórico cartagenero [Hojas Resumen]

Viviendas equipadas para estudiantes en la c/Sor Francisca Armendáriz (Cartagena

Viviendas equipadas para estudiantes en la c/Sor Francisca Armendáriz (Cartagena) : Microreordenación del casco histórico cartagenero [Hojas Resumen]

Viviendas equipadas para estudiantes en la c/Sor Francisca Armendáriz (Cartagena