Integrated Cascade Process for the Catalytic Conversion of 5-Hydroxymethylfurfural to Furanic and Tetrahydrofuranic Diethers as Potential Biofuels

The depletion of fossil resources is driving the research towards alternative renewable ones. Under this perspective, 5-hydroxymethylfurfural (HMF) represents a key molecule deriving from biomass characterized by remarkable potential as platform chemical. In this work, for the first time, the hydrogenation of HMF in ethanol was selectively addressed towards 2,5-bis(hydroxymethyl)furan (BHMF) or 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) by properly tuning the reaction conditions in the presence of the same commercial catalyst (Ru/C), reaching the highest yields of 80 and 93 mol%, respectively. These diols represent not only interesting monomers but strategic precursors for two scarcely investigated ethoxylated biofuels, 2,5-bis(ethoxymethyl)furan (BEMF) and 2,5-bis(ethoxymethyl)tetrahydrofuran (BEMTHF). Therefore, the etherification with ethanol of pure BHMF and BHMTHF and of crude BHMF, as obtained from hydrogenation step, substrates scarcely investigated in the literature, was performed with several commercial heterogeneous acid catalysts. Among them, the zeolite HZSM-5 (Si/Al=25) was the most promising system, achieving the highest BEMF yield of 74 mol%. In particular, for the first time, the synthesis of the fully hydrogenated diether BEMTHF was thoroughly studied, and a novel cascade process for the tailored conversion of HMF to the diethyl ethers BEMF and BEMTHF was proposed

Cascade Valorization of 5-Hydroxymethylfurfural (HMF) to Monomers and Furanic/Tetrahydrofuranic Diethers Bio-fuels

5-hydroxymethylfurfural (HMF) represents a valuable platform-chemical for the synthesis of monomers and bio-fuels. Thus, the present work proposes, for the first time, a cascade process for the synthesis of diol monomers and furanic/tetrahydrofuranic diethers as novel bio-fuels starting from HMF. In the first step, the selective hydrogenation of HMF in ethanol to give 2,5- bis(hydroxymethyl)furan (BHMF) or 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) was carried out by properly tuning the reaction conditions in the presence of 5 wt% Ru/C as catalyst, reaching the highest yields of 80 and 93 mol%, respectively. These diols are strategic precursors for two scarcely investigated ethoxylated bio-fuels, 2,5-bis(ethoxymethyl)furan (BEMF) and 2,5- bis(ethoxymethyl)tetrahydrofuran (BEMTHF). Thus, in the second step, the etherification of both pure BHMF and BHMTHF to give BEMF and BEMTHF, respectively, was studied. The zeolite HZSM-5 (Si/Al = 25) allowed the achievement of the highest BEMF yield of 74 mol%. Analogous results were also obtained starting from crude BHMF. On the contrary, BEMTHF was not obtained by the direct etherification of BHMTHF, but a preliminary study showed the possibility of synthesising BEMTHF by the 5 wt% Ru/C catalyzed hydrogenation of BEMF. Finally, the stability of the tested catalysts was investigated, showing that they maintained the activity almost constant up to five recycle runs, thus resulting recyclable

Mondor's disease as a complication in breast surgery in a male patient. The first ever reported case in literature

Mondor's disease (MD) is an uncommon clinical condition characterized by thrombophlebitis of the superficial veins of the anterolateral thoracoabdominal wall. In this paper we present the first ever reported case of Mondor's disease in male patient after surgical correction of gynecomastia with liposuction assisted skin sparing adenectomy

PRIN LEVANTE 2020: VALORIZZAZIONE DELL’ACIDO LEVULINICO ATTRAVERSO TECNOLOGIE INNOVATIVE

Il progetto LEVANTE si focalizza sullo sviluppo di nuovi processi catalitici volti alla valorizzazione dell’acido levulinico e dei suoi esteri verso tre classi di composti: i rispettivi chetali, l’acido difenolico, il γ-valerolattone e i successivi prodotti di riduzione. Il progetto LEVANTE sarà sviluppato in accordo con i principi della green chemistry e della sostenibilità dei processi produttivi, aprendo così la strada a tecnologie innovative per la completa valorizzazione di tale composto

Niobium and Zirconium Phosphates as Green and Water-Tolerant Catalysts for the Acid-Catalyzed Valorization of Bio-Based Chemicals and Real Lignocellulosic Biomasses

Commercial niobium and synthesized zirconium phosphates were tested as water-tolerant heterogeneous acid catalysts in the hydrothermal conversion of different bio-based substrates. Different acid-catalyzed reactions were performed using biomass-derived model compounds and more complex real lignocellulosic biomasses as the substrate. The conversion of glucose and cellulose was preliminarily investigated. Then, a wide plethora of raw lignocellulosic biomasses, such as conifer wood sawdust, Jerusalem artichoke, sorghum, miscanthus, foxtail millet, hemp and Arundo donax, were valorized towards the production of water-soluble saccharides, 5-hydroxymethylfurfural (HMF), levulinic acid (LA) and furfural. The different catalytic performances of the two phosphates were explained on the basis of their acid features, total acidity, Brønsted/Lewis acid sites ratio and strength. Moreover, a better insight into their structure–acidity relationship was proposed. The different acid properties of niobium and zirconium phosphates enabled us to tune the reaction towards target products, achieving from glucose maximum HMF and LA yields of 24.4 and 24.0 mol%, respectively. Remarkably, when real Jerusalem artichoke biomass was adopted in the presence of niobium and zirconium phosphate, maximum yields of furanic compounds and cellulose-derived sugars of 12.7 and 50.0 mol%, respectively, were obtained, after only 1 h of reaction. The synthesized hydrolysates, which were found to be rich in C5 and C6 carbohydrates, can be better exploited for the cascade production of more added-value bio-products

Malignancy-associated X chromosome allelic losses in foregut endocrine neoplasms: further evidence from lung tumors

n/

Decision making under hypoxia: Oxygen depletion increases risk seeking for losses but not for gains

We report a preliminary study that compared decisions made in an oxygen depleted environment with those made in a normoxic environment. Participants were presented with a series of choices that involved either losses or gains. For each choice they were forced to choose between a sure thing and a gamble of the same expected value. For choices involving losses, participants were more risk seeking in the oxygen depleted environment; for those involving gains, no difference was found

Niobium and Zirconium Phosphates as Green and Water-Tolerant Catalysts for the Acid-Catalyzed Valorization of Bio-Based Chemicals and Real Lignocellulosic Biomasses

Commercial niobium and synthesized zirconium phosphates were tested as water-tolerant heterogeneous acid catalysts in the hydrothermal conversion of different bio-based substrates. Different acid-catalyzed reactions were performed using biomass-derived model compounds and more complex real lignocellulosic biomasses as the substrate. The conversion of glucose and cellulose was preliminarily investigated. Then, a wide plethora of raw lignocellulosic biomasses, such as conifer wood sawdust, Jerusalem artichoke, sorghum, miscanthus, foxtail millet, hemp and Arundo donax, were valorized towards the production of water-soluble saccharides, 5-hydroxymethylfurfural (HMF), levulinic acid (LA) and furfural. The different catalytic performances of the two phosphates were explained on the basis of their acid features, total acidity, Brønsted/Lewis acid sites ratio and strength. Moreover, a better insight into their structure–acidity relationship was proposed. The different acid properties of niobium and zirconium phosphates enabled us to tune the reaction towards target products, achieving from glucose maximum HMF and LA yields of 24.4 and 24.0 mol%, respectively. Remarkably, when real Jerusalem artichoke biomass was adopted in the presence of niobium and zirconium phosphate, maximum yields of furanic compounds and cellulose-derived sugars of 12.7 and 50.0 mol%, respectively, were obtained, after only 1 h of reaction. The synthesized hydrolysates, which were found to be rich in C5 and C6 carbohydrates, can be better exploited for the cascade production of more added-value bio-products

Aspettando il Sessantotto

Nei contributi qui presentati, vengono analizzati alcuni momenti e figure della vita e del dibattito politico in Italia, nel dodicennio che precede l’esplosione del 1968. Sono evidenziati – nella continuità delle diverse culture politiche – gli elementi di discontinuità, le incrinature, i dissensi, le eterodossie, le polemiche: tutto ciò che in qualche modo, può essere considerato un dato “preparatorio” del sommovimento di fine decennio