DQO-Artículos, capítulos...
http://hdl.handle.net/10396/2324
2024-03-28T20:48:04ZA Continuous flow approach for the desulfurative bromination of sulfides
http://hdl.handle.net/10396/27701
A Continuous flow approach for the desulfurative bromination of sulfides
Pineda, Antonio; Carr, James; Rodríguez-Padrón, Daily; Lázaro, Noelia; Fox, Karen; Gonzalez-Arellano, Camino; Gillick-Healy, Malachi W.; Kelly, Brian G.; Adamo, Mauro F. A.; Luque, Rafael
The preparation of alkyl bromides is a pivotal transformation in organic chemistry. The wide range of applications that bromides have as building blocks render this class of compounds a privileged motif widely used in the manufacture of active pharmaceutical ingredients. Traditionally prepared from the deoxygenation of alcohols, alkyl bromides have been recently obtained from sulfides in high yields, a transformation we have named desulfurative bromination. In order to improve the efficiency of this transformation, we report herein the investigation and optimisation of a continuous flow strategy. The influence of the flow rate; role of the brominating agent; and substrate scope have been studied delivering an in-flow protocol to access multigram quantities of these valuable intermediates
2024-01-01T00:00:00ZTuning the Selectivity of the Hydrogenation/Hydrogenolysis of 5-Hydroxymethylfurfural under Batch Multiphase and Continuous-Flow Conditions
http://hdl.handle.net/10396/27698
Tuning the Selectivity of the Hydrogenation/Hydrogenolysis of 5-Hydroxymethylfurfural under Batch Multiphase and Continuous-Flow Conditions
Rodríguez-Padrón, Daily; Perosa, Alvise; Longo, Lilia; Luque, Rafael; Selva, Maurizio
The hydrogenation/hydrogenolysis of 5-hydroxymethylfurfural (HMF) has been carried out either under single (aqueous) phase or batch multiphase (MP) conditions using mutually immiscible aqueous/hydrocarbon phases, 5?% Ru/C as a catalyst, and both with and without the use of trioctylmethyl phosphonium bis-(trifluoro methane) sulfonimide ([P8881][NTf2]) as an ionic liquid (IL). Alternatively, the hydrogenation of HMF was explored in the continuous-flow (CF) mode with the same catalyst. By changing reaction parameters, experiments were optimized towards the formation of three products: 2,5-bis(hydroxy methyl)furan (BHMF), 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF), and 1-hydroxyhexane-2,5-dione (HHD), which were obtained in up to 92, 90, and 99?% selectivity, respectively, at quantitative conversion. In particular, the single (aqueous) phase reaction of HMF (0.2?m) carried out for 18?h at 60?°C under 30?bar of H2, allowed the exclusive synthesis of BHMF from the partial (carbonyl) hydrogenation of HMF, while the MP reaction run at a higher T and p (100?°C and 50?bar) proved excellent to achieve only HHD derived from a sequence of hydrogenation/hydrogenolysis. It is worth noting that under MP conditions, the catalyst was perfectly segregated in the IL, where it could be recycled without any leaching in the aqueous/hydrocarbon phases. Finally, the hydrogenation of HMF was explored in a H-Cube? flow reactor in the presence of different solvents, such as ethyl acetate, tetrahydrofuran, and ethanol. At 100?°C, 50?bar H2, and a flow rate of 0.1?mL?min?1, the process was optimized towards the formation of the full hydrogenation product BHMTHF. Ethyl acetate proved the best solvent.
2022-01-01T00:00:00ZStudy on the Performance and Emissions of Triple Blends of Diesel/Waste Plastic Oil/Vegetable Oil in a Diesel Engine: Advancing Eco-Friendly Solutions
http://hdl.handle.net/10396/27660
Study on the Performance and Emissions of Triple Blends of Diesel/Waste Plastic Oil/Vegetable Oil in a Diesel Engine: Advancing Eco-Friendly Solutions
Estevez, Rafael; Aguado-Deblas, Laura; López-Tenllado, Francisco J.; Bautista, Felipa M.; Romero, Antonio A.; Luna, Diego
To provide technical and economical solutions regarding management of plastic waste, which is constantly increasing worldwide, this study addresses the possibility of using plastic oils (PO) obtained from these plastic wastes as biofuels. To this end, the replacement of the fossil diesel employed in internal combustion diesel engines with triple diesel/PO/vegetable oil mixtures has been investigated. Sunflower (SO) and castor oil (CO) mixed with PO in the most appropriate proportion are evaluated as pure vegetable oils (SVO). Thus, diesel/PO/SVO triple blends were prepared, characterized, and then tested on a diesel engine operating as electricity generator, evaluating power output, consumption, and exhaust emissions. The obtained results show that, with the incorporation of relatively small quantities of pure, non-edible vegetable oils, in double mixtures of PO/SO and PO/CO, an effective alternative fuel for transport is obtained, that allows for 100% of fossil diesel to be replaced. In fact, with these double PO/SVO biofuel mixtures, higher engine power values and lower consumption levels are obtained than those achieved with fossil diesel. Regarding exhaust emissions, these are produced with a slightly greater opacity than with fossil diesel, but there are lower values of carbon gases as a whole (CO + CO2) and in NOx gases.
2024-01-01T00:00:00ZInternal combustion engines and carbon-neutral fuels: a perspective on emission neutrality in the European Union
http://hdl.handle.net/10396/27602
Internal combustion engines and carbon-neutral fuels: a perspective on emission neutrality in the European Union
Estévez, R.; Aguado-Deblas, Laura; López Tenllado, Francisco Javier; Bautista, Felipa M.; Romero, Antonio A.; Luna, Diego
Nowadays, there is an intense debate in the European Union (EU) regarding the limits to achieve the European Green Deal, to make Europe the first climate-neutral continent in the world. In this context, there are also different opinions about the role that thermal engines should play. Furhermore, there is no clear proposal regarding the possibilities of the use of green hydrogen in the transport decarbonization process, even though it should be a key element. Thus, there are still no precise guidelines regarding the role of green hydrogen, with it being exclusively used as a raw material to produce E-fuels. This review aims to evaluate the possibilities of applying the different alternative technologies available to successfully complete the process already underway to achieve Climate Neutrality by about 2050, depending on the maturity of the technologies currently available, and those anticipated to be available in the coming decades.
2024-01-01T00:00:00Z