Editorial for the Special Issue on “Multidisciplinary Insights on Bone Healing”

: Animal and human bone damage can be considered differently according to a macro- or micro-level analysis [...]

In operando XAS investigation of reduction and oxidation processes in cobalt and iron mixed spinels during the chemical loop reforming of ethanol

FeCo2O4 and CoFe2O4 nanoparticles have been studied as oxygen carriers for the Chemical Loop Reforming (CLR) of ethanol. By using in operando X-ray absorption spectroscopy we have followed in real time the chemical and structural changes that take place on the materials as a function of temperature and reactive atmosphere (i.e. ethanol/water streams). During the first step of CLR for both oxides the most active chemical species are the cations in the tetrahedral sites, irrespective of their chemical nature. Quite rapidly the spinel structure is transformed into a mix of wustite-type oxide and metal alloys, but the formation of a metal phase is easier in the case of cobalt, while iron shows a marked preference to form wustite type oxide. Despite the good reducibility of FeCo2O4 imparted by the high amount of cobalt, its performance in the production of hydrogen is quite poor due to an inefficient oxidation by water steam, which is able to oxidize only the outer shell of the nanoparticles. In contrast, CoFe2O4 due to the residual presence of a reducible wustite phase shows a higher hydrogen yield. Moreover, by combining the structural information provided by X-ray absorption spectroscopy with the analysis of the byproducts of ethanol decomposition we could infer that FeCo2O4 is more selective than CoFe2O4 for the selective dehydrogenation of ethanol to acetaldehyde because of the higher amount of Fe(III) ions in tetrahedral sites

The Oxidative Cleavage of 9,10-Dihydroxystearic Triglyceride with Oxygen and Cu Oxide-based Heterogeneous Catalysts

This paper deals with a new heterogeneous catalyst for the second step in the two-step oxidative cleavage of unsaturated fatty acids triglycerides derived from vegetable oil, a reaction aimed at the synthesis of azelaic and pelargonic acids. The former compound is a bio-monomer for the synthesis of polyesters; the latter, after esterification, is used in cosmetics and agrochemicals. The reaction studied offers an alternative to the currently used ozonization process, which has severe drawbacks in terms of safety and energy consumption. The cleavage was carried out with oxygen, starting from the glycol (dihydroxystearic acid triglyceride), the latter obtained by the dihydroxylation of oleic acid triglyceride. The catalysts used were based on Cu2+, in the form of either an alumina-supported oxide or a mixed, spinel-type oxide. The CuO/Al2O3 catalyst could be recovered, regenerated, and recycled, yielding promising results for further industrial exploitation

Sustainable isosorbide production by a neat one-pot MW-assisted catalytic glucose conversion

In the context of exploitation of new biomass-derived platform chemicals, isosorbide (1,4:3,6-dianhydro-D-sorbitol), obtained by the two-fold dehydration of sorbitol, is gaining increasing interest in several potential industrial applications. Seeking for more sustainable, efficient, and economically competitive green processes, the use of heterogeneous catalysts under microwave (MW) irradiation has been adopted for the development of a neat one-pot process from glucose. MW-assisted catalytic processes have shown the potential to reduce the reaction time and improve the selectivity, due to the interaction of MW with the reaction medium through the production of hot spots on the catalyst surface. Ru/C, Ru/Al2O3 and Ru/TiO2 were tested for glucose hydrogenation to sorbitol, while the dehydration step was favored by the addition of beta Zeolites (360:1 SiO2:Al2O3) allowing high isosorbide selectivity (>85 %). An extended structural and morphological characterization before and after the catalytic tests allowed to establish structure-activity relationships. Yields up to 47.1 % have been obtained directly from glucose in 1.5 h, achieving a considerable reduction of reaction time without the use of a solvent. thus paving the way for further investigations on biomass conversion into value-added products. With this aim, direct isosorbide production from milled cellulose was investigated. While the isosorbide yields still need to be improved, the dual role of formic acid both as acid catalyst for cellulose hydrolysis and H-donor for the reduction step was promisingly clarified

Integrated Cascade Process for the Catalytic Conversion of 5-Hydroxymethylfurfural to Furanic and TetrahydrofuranicDiethers 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

Gas-phase oxidative dehydrogenation of long chain alkenols for the production of key fragrance ingredients: from Rosalva isomers to Costenal analogues

The continuous-flow, gas-phase oxidative dehydrogenation (ODH) of an actual mixture of decen-1-ol isomers ("Isorosalva" alcohol) towards the corresponding mixture of aldehydes ("Costenal" analogues, valuable ingredients in perfumes formulation) is herein reported for the first time over noble metal-free catalysts. In particular, the optimisation of the reaction conditions over a copper ferrite (Cu/Fe/O), as well as dedicated characterizations and comparisons between the fresh, the post-reaction (reduced) and regenerated (re-oxidised) catalytic material, allowed us to underline the key role of well dispersed copper oxide over a Fe-enriched spinel in promoting the selective ODH of Isorosalva alcohol. The superior catalytic activity and selectivity of CuO/gamma-Fe2O3 synthesized ad hoc were attributed to the very high dispersion of Cu over the support as well as to a cooperative effect between Cu and Fe species in promoting the redox cycle

EPR enlightening some aspects of propane ODH over VOx\u2013SiO2 and VOx\u2013Al2O3

In the oxidative dehydrogenation (ODH) of propane to propylene VOx-based catalysts prepared by name pyrolysis (FP) showed more selective than those prepared by impregnation. Furthermore, samples prepared by the same method were less active, but more selective when VOx was supported on SiO2 than on Al2O3. In order to assess V local structure, V4+ ions showed useful labels to characterise these catalysts by EPR spectroscopy. Indeed, the spectrum of a (10 wt%V2O5) FP-prepared VOx/SiO2 catalyst was typical of isolated, tetragonally distorted, paramagnetic complexes of V4+ forming a monolayer on the sample surface with a strong out-of-plane V4+-O bond. In a sample with identical composition, but prepared by impregnation, this bond showed a bit weaker. Furthermore, ferromagnetic domains of clustered V ions formed in the latter sample, hindering at least in part the accessibility to the catalytically active V-based centres. This gives evidence of the higher dispersion of V in the sample bulk provided by the FP preparation method with respect to conventional ones. A by far weaker V4+-O bond was revealed by the EPR spectrum of a (10%V2O5) VOx/Al2O3 sample, accounting for its higher oxygen availability, leading to higher activity, but lower selectivity. However, the same catalyst, when prepared by impregnation, showed a ferromagnetic resonance pattern so intense that no EPR spectrum was detectable at all and no information on the V4+-O bond strength was available in that case. Such semi-quantitative index of the V-O bond strength can be used as an index of oxygen availability, as a tool to assess catalytic activity and selectivity to the desired olefin

Relationship between pectoralis major muscle histology and quality traits of chicken meat

A trial was conducted to evaluate the influence of myodegeneration of pectoralis major muscle on quality traits and chemical composition of breast meat of heavy size male broilers. For this purpose, a total of 72 pectoralis major muscles were randomly collected from broilers farmed under homogeneous conditions and graded into three categories (mild, n= 22; moderate, n=33; and severe, n=17) based on the presence of abnormal fibers (giant fibers, fibers with hyaline degeneration and damaged and/or necrotic fibers) evaluated by histological and immunohistochemical analysis. Color, pH, drip and loss, Allo-Kramer shear values and chemical composition (moisture, proteins, total lipids, ashes and collagen) were determined on non-marinated breast meat, as well as purge loss and cook loss, total yield and Allo-Kramer shear values were measured on vacuum tumbled samples. Samples showing moderate myodegeneration had the highest mean cross-sectional area of the fibers, while samples with severe myodegeneration had myofibers of different diameter and without the characteristic polygonal shape, multifocal degeneration and necrosis, as well as infiltration of CD3-immunoreactive cells. Cooking losses of non-marinated meat were lower in mild group in respect to moderate and severe groups (21.4 vs. 24.7 and 24.7%; P<0.001). Breast muscles with severe damages, in comparison with mild degenerated samples, showed higher moisture (75.4 vs. 74.4%; P<0.05) and lower protein percentages (21.1 vs. 22.6%; P<0.001). The lipid percentage of severe degenerated samples was higher than that from moderate group (2.94 vs. 2.36; P<0.05), while collagen content was not modified by histological lesion levels. Marinated meat from mild group had higher uptake and total marinade yield after cooking. In conclusion, almost all breast fillets of heavy broiler chickens produced under intensive farming systems had histological lesions which reflected on chemical composition of meat and impaired water holding/binding capacities of the meat

1-Butanol dehydration and oxidation over vanadium phosphate catalysts

The transformation of 1-butanol into either butenes or maleic anhydride was carried out both with and without oxygen, using V/P/O catalysts. With vanadyl pyrophosphate prepared by coprecipitation, at temperature lower than 240 ◦C and without oxygen, selectivity to butenes was higher than 90%, but a slow deactivation took place. At temperature higher than 300 ◦C and in the presence of air, maleic and phthalic anhydrides were the prevailing products, with selectivity of 60% and 14%, respectively. Catalytic performance was affected by crystallinity and acidity. αI-VOPO4 showed a poor performance in the absence of air, with a quick deactivation due to coke accumulation; but it displayed an excellent selectivity to butenes (close to 98%) at temperatures lower than 320 ◦C in the presence of air, with stable performance. At temperature higher than 360 ◦C, α I-VOPO4 was reduced to vanadyl pyrophosphate and catalyzed the direct oxidation of 1-butanol into maleic anhydride, but with 35% selectivit