Search results for "Organic chemistry"
showing 10 items of 17180 documents
Characterization of lignin enforced tannin/furanic foams
2020
Worldwide, tons of lignin is produced annually in pulping plants and it is mainly considered as a waste material. Usually lignin is burned to produce energy for the pulping reactors. The production of value-added materials from renewable materials like lignin, has proved to be challenging. In this study, the effects of addition of three different types of lignin in the production of tannin/furanic foams is investigated. The foams were matured, first at 373 K and finally carbonized at 1073 K and the properties of them including mechanical strength, specific surface area and pore development are investigated before and after thermal treatment. According to the results, higher mechanical stren…
Task-Specific Organic Salts and Ionic Liquids Binary Mixtures: A Combination to Obtain 5-Hydroxymethylfurfural From Carbohydrates
2019
The increase in energy demand and depletion of fossil fuels are among major issues of modern society. Valorization and transformation of raw materials in products of industrial value represents a challenge. This justifies the growing interest of scientific research towards the identification of suitable media and methodologies able to pursue above goals, paying attention to matter of sustainability. On this subject, we studied sulfonic-acid functionalized diimidazolium salts as catalysts for the conversion of fructose and sucrose to 5-hydroxymethylfurfural (5-HMF) in an ionic liquid mixture. In general, using these salts allowed us to obtain 5-HMF in good yields from both substrates in mild…
Chemical composition of the essential oil of Elaeoselinum asclepium (L.) Bertol subsp. meoides (Desf.) Fiori (Umbelliferae) collected wild in Central…
2020
In the present study, the chemical composition of the essential oils from flowers and leaves of Elaeoselinum asclepium(L.) Bertol subsp. meoides(Desf.) Fiori collected in Central Sicily was evaluated by GC and GC-MS. The main volatile components of the flowers were alpha-phellandrene (42.5%), terpinolene (15.7%), p-cymene (11.6%) and beta-phellandrene (10.2%), whereas the ones of the leaves were p-cymene (44.0%), alpha-pinene (13.2%), alpha-phellandrene (11.0%), beta-phellandrene (10.2%) and beta-pinene (9.2%). Furthermore, the antibacterial and antifungal activities against some microorganisms infesting historical art craft were determined. The essential oil from leaves (EL) showed to be p…
Densities, Refractive Indices, and Derived Excess Properties of the Binary Systems Toluene + Isooctane and Methylcyclohexane + Isooctane and the Tern…
2000
This paper reports mesurements of the densities and refractive indices of the binary systems toluene + isooctane and methylcyclohexane + isooctane and the ternary systems tert-butyl alcohol (TBA) + toluene + isooctane and tert-butyl alcohol (TBA) + methylcyclohexane + isooctane over the entire range of composition at 298.15 K. Excess molar volumes and changes of refractive indices were evaluated from the experimental data obtained. These derived properties were fitted to variable-degree polynomials. The experimental values of physical properties were compared with the values estimated by different methods.
2-Methylresorcinarene: a very high packing coefficient in a mono-anion based dimeric capsule and the X-ray crystal structure of the tetra-anion
2016
Mono- and tetra-deprotonated 2-methylresorcinarene anions (1 and 2) as their trans-1,4-diammoniumcyclohexane (TDAC)2+ inclusion complexes are reported. The mono-anion forms a fully closed dimeric capsule [1·H2O·MeOH]22− with a cavity volume of 165 Å3 and (TDAC)2+ as the guest with an extremely high packing coefficient, PC = 84.2%, while the tetra-anion forms a close-packed structure with two structurally isomeric tetra-anions 2a and 2b with a 50 : 50 ratio in the crystal lattice. peerReviewed
Spin Crossover in Fe(II)–M(II) Cyanoheterobimetallic Frameworks (M = Ni, Pd, Pt) with 2-Substituted Pyrazines
2016
Discovery of spin-crossover (SCO) behavior in the family of Fe(II)-based Hofmann clathrates has led to a "new rush" in the field of bistable molecular materials. To date this class of SCO complexes is represented by several dozens of individual compounds, and areas of their potential application steadily increase. Starting from Fe(2+), square planar tetracyanometalates M(II)(CN)4(2-) (M(II) = Ni, Pd, Pt) and 2-substituted pyrazines Xpz (X = Cl, Me, I) as coligands we obtained a series of nine new Hofmann clathrate-like coordination frameworks. X-ray diffraction reveals that in these complexes Fe(II) ion has a pseudo-octahedral coordination environment supported by four μ4-tetracyanometallat…
A Particular Focus on the Prevalence of α- and β-Thalassemia in Western Sicilian Population from Trapani Province in the COVID-19 Era
2023
Thalassemia is a Mendelian inherited blood disease caused by α- and β-globin gene mutations, known as one of the major health problems of Mediterranean populations. Here, we examined the distribution of α- and β-globin gene defects in the Trapani province population. A total of 2,401 individuals from Trapani province were enrolled from January 2007 to December 2021, and routine methodologies were used for detecting the α- and β-globin genic variants. Appropriate analysis was also performed. Eight mutations in the α globin gene showed the highest frequency in the sample studied; three of these genetic variants represented the 94% of the total α-th…
The Scope of Application of Macrocyclic Polyamines Beyond Metal Chelation
2019
International audience; Recent advances in the use of radiometals for both imaging and therapy has spurred on the development of an original chemistry that endows radionuclide-chelating molecular cages with ever sharper physicochemical properties. Macrocyclic polyamines (MPAs) such as cyclen and DOTA are among the most frequently encountered cages for the design of new radiotracers, owing to their versatile chemistry that makes them customizable molecular tools. The idea of using MPAs for alternative purposes has recently emerged, with an eye towards benefiting from their unique topology, versatility, symmetry and water-solubility. This review summarizes strategies that have been recently i…
On the Choice of the Extracellular Vesicles for Therapeutic Purposes
2019
Extracellular vesicles (EVs) are lipid membrane vesicles released by all human cells and are widely recognized to be involved in many cellular processes, both in physiological and pathological conditions. They are mediators of cell-cell communication, at both paracrine and systemic levels, and therefore they are active players in cell differentiation, tissue homeostasis, and organ remodeling. Due to their ability to serve as a cargo for proteins, lipids, and nucleic acids, which often reflects the cellular source, they should be considered the future of the natural nanodelivery of bio-compounds. To date, natural nanovesicles, such as exosomes, have been shown to represent a source of diseas…
A library of monoalkenylsilsesquioxanes as potential comonomers for synthesis of hybrid materials
2018
In this paper we demonstrate a facile and efficient synthesis of monoalkenylsubstituted POSS compounds, i.e., R7(Si8O12)-alkenyl and R7(Si8O12)(OSiMe2)-alkenyl with a functional alkenyl group of chain length (from vinyl to dec-9-enyl, with or without additional –OSiMe2– spacer between the silsesquioxane core and alkenyl moiety) and with five types of inert groups (Et, iBu, iOc, Cy, Ph) at the POSS core. These compounds constitute a library of monosubstituted POSS systems, including thorough spectroscopic and thermal characteristics. These findings could be especially useful for material chemists applying the compounds as modifiers or comonomers for copolymerization reaction, e.g., with olef…