Catalytic Biomass Upgrading Exploiting Liquid Organic Hydrogen Carriers (LOHCs)

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:9 issue:29 pages:9604-9624 status: publishe

Controlling crystallization damage by the use of salt inhibitors on Malta's limestone

Parallel text in Spanish and EnglishThe main building stone in the Maltese Islands is the Globigerina Limestone, of which the Lower member is commonly used. This occurs in two types, the durable franka and the more easily weathered soll. Two types of fresh franka (bajda (white) and safra (yellow)), as well as fresh soll stone blocks, were obtained, based on the identification by quarry owners. Their designation was confirmed by geochemistry. Physical and mechanical properties of the three were investigated, including uniaxial compressive strength, water absorption by capillarity, permeability and porosimetry. Porosimetry results confirmed outcomes of previous research work. Soll was found to have a lower overall porosity, but a high percentage of small pores with practically no large pores. Some of the tested stones were then treated with a non-toxic phospho- organic compound containing carboxylic moieties as a salt inhibitor and the corresponding non-phosphorylated compound.peer-reviewe

spectral properties and photophysics of arylacetylenes in thin films

AbstractWe report the photobehaviour of a series of eight structurally related arylacetylene derivatives, in solution as well as in pristine and PC61BM blended thin-_lms. The formation of both H- and J-aggregates in the solid state have been demonstrated, and, interestingly, an energy transfer from H-aggregates or/and from residual "unstacked" molecules to J-aggregates has been found, the latter being the only emitting species. The fuorescence quenching by PC61BM at di_erent loadings has been studied in blend films, and it has been found particularly effcient in the case of a symmetrical peripheral substitution of the acetylene derivative core. Preliminary time-resolved measurements in emission (ns resolution) and in absorption (fs resolution) con_rmed the H⟶J energy transfer and underlined the presence of delayed fuorescence from Jaggregates, formed by energy transfer from the long-lived first excited singlet state of H-aggregates. In all cases, a homogeneous surface morphology of thin films

Investigating a method to limit damage in Globigerina Limestone, a soft porous stone widely used in historic buildings

A programme of studies is ongoing to investigate the action of environmentally-friendly functionalized polycarboxylates as organic crystallization modifiers on salts on two types of Globigerina Limestone of Malta, to compare their action and behaviour. This was mainly done to verify the potential of such compounds to control, and therefore, limit damage on this locally unexplored territory. The main thrust of the research, at this stage, was to observe modifications to solution transport and salt crystal growth induced in two varieties of the stone by treating under controlled laboratory conditions; work under uncontrolled conditions has also commenced, but will not be discussed here. In this paper, indications of the modifications obtained are discussed, in the context of former trials, the fact that they are still under investigation and with a view on way forward. A discussion establishing a classification for damage limitation is postulated.peer-reviewe

Acetylene-Based Materials in Organic Photovoltaics

Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (poly)arylacetylenes that have been used in the field. A general introduction to (poly)arylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (co)polymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C60, and their use as the active materials in photovoltaic devices

Editorial for “Materials Chemistry” Sections on Molecules

Materials chemistry has been one of the most talked-about areas of materials research over the past decades [...

Advances in green chemistry and engineering

Abstract Green chemistry and engineering seek for maximizing efficiency and minimizing negative impacts on the environment and human health in chemical production processes. Driven by advances in the principles of environment protection and sustainability, these fields are expected to greatly contribute to achieving sustainable development goals. To this end, many studies have been conducted to develop new approaches within green chemistry and engineering. The Advances in Green Chemistry and Engineering Collection at Scientific Reports aims at gathering the latest research on developing and implementing the principles of green chemistry and engineering

Waste-minimized C(sp3)-H activation for the preparation of fused N-heterocycles

By exploiting the combined use of a heterogeneous recyclable palladium(II)-bis(N-heterocyclic carbene) catalyst and cyclopentyl methyl ether (CPME) as a convenient recoverable safer reaction medium, an effective waste-minimized approach has been developed for the intramolecular Pd-catalyzed C(sp3)-H activation of methyl pyrrole derivatives. This synthetic tools has allowed to access condensed N-heterocycles generally endowed with biological activities and representatively are the core motif of complex molecules such as Mitomycines and Tylophorines. The heterogeneous catalytic system could be recovered and reused up to representative five runs without any loss in efficiency. The target products (19 examples) have been obtained selectively and with excellent isolated yields up to 93%. The approach leads to the definition of a protocol with a very good E-factor (21) which is much lower (up to 98%) than those of comparable literature examples. Other green metrics have been calculated and the data collected demonstrate that our newly developed protocol is very promising in terms of its environmental impact profile