Search results for "SOLVENT"
showing 10 items of 1395 documents
Catalytic activity of humic substances in condensation reactions
1998
Abstract Humic substances (HS) have considerable impact on the fate of organic xenobiotics in natural environments. This paper reports on the catalytic activity of HS in condensation reactions of carbonyl compounds with active methylene compounds, using Knoevenagel and Claisen-Schmidt reactions as examples. Of the HS, the aquatic fulvic acids are the most active, but the velocity of condensation reactions depends also on the temperature, concentration and form of HS (free or salt) used, and the solvent.
Dynamic of Components Leachate from Experimental Fertilizers in Leaching Test
2018
Organic matter contained in the waste of food industry or occurring in the households, in the absence of contamination with other kind of waste, may be used to create a “fertiliser”, which could be even reused in the organic production of arable crops. Particular attention is drawn to the fertilisers which may be applied in the case of amateur cultivation of pot plants and in the allotment gardens. The paper presents the results of research regarding the dynamics of the release of nutrients from tablets created with the help of encapsulation of the mixture manufactured from solvent extraction waste of coffee (SCG), modified by the ash obtained from low temperature burning of biomass. In thi…
Liquid Phase Micro-Extraction of Linear Alkylbenzene Sulfonate Anionic Surfactants in Aqueous Samples
2011
Hollow fiber liquid phase micro-extraction (LPME) of linear alkylbenzene sulfonates (LAS) from aqueous samples was studied. Ion pair extraction of C10, C11, C12 and C13 homologues was facilitated with trihexylamine as ion-pairing agent, using di-n-hexylether as solvent for the supported liquid membrane (SLM). Effects of extraction time, acceptor buffer concentration, stirring speed, sample volume, NaCl and humic acids were studied. At 10–50 µg L−1 linear R2-coefficients were 0.99 for C10 and C11 and 0.96 for C12. RSD was typically ~15%. Three observations were especially made. Firstly, LPME for these analytes was unusually slow with maximum enrichment observed after 15–24 h (depending on sa…
Analysis of Lipophilic Extractives from Fast Pyrolysis Bio-Oils
2022
Fast pyrolysis bio-oils (FPBOs) originating from forest residues contain extractive-derived substances, which may form a separate, sticky layer with char particles on the surface of these bio-oils. In this study, first, the removal of extractive-derived substances from the bio-oil top phase was studied by common solvents with different polarities. In this case, the results indicated that when aimed at the maximum yield of single-phase fuel oil and thus the maximum amount of extractives removed, the use of n-heptane or n-hexane seems to be of benefit for this purpose. For safety reasons, the use of n-heptane was recommended. Second, an analysis practice (extraction time and the way of mixing…
Unconventional synthesis and properties of zeolitic imidazolate frameworks and 2D magnetic MOFs
2021
Esta tesis fue planteada para el desarrollo de nuevos polímeros de coordinación y materiales híbridos metalorgánicos (MOFs) basados en rutas sintéticas novedosas en ausencia de disolvente. Esta novedosa metodología de síntesis permite acceder a nuevos materiales inalcanzables por rutas más clásicas como las solvotermales. La tesis se centra en la obtención de materiales basados en Fe(II), el cual es sensible a ser oxidado durante las reacciones de formación de MOFs a Fe(III). Por ello se utilizó una síntesis en ausencia de disolvente en atmosfera inerte compatible con Fe(II). Para ello se utiliza una familia de ligandos sublimables tipo imidazol y metalocenos, como el ferroceno como fuente …
Sensores magnéticos basados en polímeros de coordinación porosos con ordenamiento magnético
2023
La Tesis que aquí se presenta tiene como objetivo principal el diseño y estudio de las propiedades de una gran serie de compuestos que actúan como imanes moleculares. Estos compuestos consisten en polímeros de coordinación basados en el ligando anilato (C6O4X22-, siendo X = Cl o Br) con metales de transición como centros metálicos responsables del comportamiento magnético de dichos materiales. Así pues, en el Capítulo 1 se presenta una familia de compuestos isoestructurales entre sí con capas aniónicas en forma de panal abeja que se superponen de modo eclipsado originando canales hexagonales. En el interior de los canales hexagonales se alojan moléculas de disolvente que tienen un papel fun…
Generation of anti-azoxystrobin monoclonal antibodies from regioisomeric haptens functionalized at selected sites and development of indirect competi…
2012
Azoxystrobin is a modern strobilurin fungicide used around the world to combat prime diseases affecting highly valuable crops. Accordingly, residues of this chemical are frequently found in food, even though mostly under maximum tolerated levels. We herein describe the development of an indirect competitive immunoassay for the determination of azoxystrobin residues. A panel of monoclonal antibodies displaying subnanomolar affinity to azoxystrobin was generated using, as immunizing haptens in mice, four functionalized derivatives carrying the same spacer arm located at different rationally chosen positions. This collection of antibodies was thoroughly characterized with homologous and hetero…
Percutaneous Stone Manipulation
1981
Percutaneous stone manipulation by direct ultrasound disintegration, extraction or chemolysis was done on 34 patients. A total of 15 patients presented with an operatively established nephrostomy, while percutaneous nephrostomy and subsequent dilation of the nephrostomy channel were done in 19. The rate of complete stone clearance was 19 of 20 stones after percutaneous nephrostomy and 8 of 16 stones in the group with an operatively established nephrostomy. The primary goal, to remove obstructing pelvic stones, was achieved in all cases. There were no untoward side effects, such as back pressure damage owing to flushing of the collecting system during ultrasound disintegration, or persistent…
Polymorphism and Metallic Behavior in BEDT-TTF Radical Salts with Polycyano Anions
2012
Up to five different crystalline radical salts have been prepared with the organic donor BEDT-TTF and three different polynitrile anions. With the polynitrile dianion tcpd2− (=C[C(CN)2]32−), two closely related radical salts: α'-(ET)4tcpd·THF (1) (THF = tetrahydrofurane) and α'-(ET)4tcpd·H2O (2) have been prepared, depending on the solvent used in the synthesis. With the mono-anion tcnoetOH− (=[(NC)2CC(OCH2CH2OH)C(CN)2]−) two polymorphs with similar physical properties but different crystal packings have been synthesized: θ-(ET)2(tcnoetOH) (3) and β''-(ET)2(tcnoetOH) (4). Finally, with the mono-anion tcnoprOH− (=[(NC)2CC(OCH2CH2CH2OH)C(CN)2]−) we have prepared a metallic…
Case-specific performance of MM-PBSA, MM-GBSA, and SIE in virtual screening.
2015
In drug discovery the reliable prediction of binding free energies is of crucial importance. Methods that combine molecular mechanics force fields with continuum solvent models have become popular because of their high accuracy and relatively good computational efficiency. In this research we studied the performance of molecular mechanics generalized Born surface area (MM-GBSA), molecular mechanics Poisson-Boltzmann surface area (MM-PBSA), and solvated interaction energy (SIE) both in their virtual screening efficiency and their ability to predict experimentally determined binding affinities for five different protein targets. The protein-ligand complexes were derived with two different app…