Letteratura scientifica selezionata sul tema "Extractable from woods"

Contact of wine with wood during fermentation and ageing produces significant changes in its chemical composition and organoleptic properties, modifying its final quality. Wines acquire complex aromas from the wood, improve their colour stability, flavour, and clarification, and extend their storage period. New trends in the use of barrels, replaced after a few years of use, have led to an increased demand for oak wood in cooperage. In addition, the fact that the wine market is becoming increasingly saturated and more competitive means that oenologists are increasingly interested in tasting different types of wood to obtain wines that differ from those already on the market. This growing demand and the search for new opportunities to give wines a special personality has led to the use of woods within the Quercus genus that are different from those used traditionally (Quercus alba, Quercus petraea, and Quercus robur) and even woods of different genera. Thus, species of the genus Quercus, such as Quercus pyrenaica Willd., Quercus faginea Lam., Quercus humboldtti Bonpl., Quercus oocarpa Liebm., Quercus frainetto Ten, and other genera, such as Robinia pseudoacacia L. (false acacia), Castanea sativa Mill. (chestnut), Prunus avium L. and Prunus cereaus L. (cherry), Fraxinus excelsior L. (European ash), Fraxinus americana L. (American ash), Morus nigra L, and Morus alba L. have been the subject of several studies as possible sources of wood apt for cooperage. The chemical characterization of these woods is essential in order to be able to adapt the cooperage treatment and, thus, obtain wood with oenological qualities suitable for the treatment of wines. This review aims to summarize the different species that have been studied as possible new sources of wood for oenology, defining the extractable composition of each one and their use in wine.

Delignification of the flax shive (wastes of oakum and heat insulation production) was studied. Chemical composition of the work material (mass parts in percents from the bone-dry material): cellulose 30,7, lignin 33,1, pentosans 28,0, extractable by organic solvent 4,3, extractable by hot water 5,4, ash 1,7. The flax shive was delignificated in laboratory condition by means of peracetic acid, hydrogen peroxide and sulfate cooking solution. The conditions of peracetic pulping: initial mass part of the «icy» acetic acid in cooking solution 0,65, perhydrol 0,35, the catalyst concentration (sodium tungstate) 0,03 g-mol/dm3, liquid module 6, temperature 92 °C; pulp yield 46,1% without of undercooked pulp. The conditions of peroxide pulping: initial concentration of hydrogen peroxide 17%, liquid module 6, complex catalyst concentration 0,1 g-mol/dm3 (molar parts of the Na2WO4, Na2MoO4 and H2SO4 in catalyst composition are 0,3 : 0,3 : 0,4 accordingly), temperature 98 °C; pulp yield 45,8% without undercooked pulp. The conditions of sulfate pulping: initial concentration of active alkali 55 g/dm3 (in Na2O unit), degree of sulfidity 18%, liquid module 4, temperature 170 °C; pulp yield 32,3% without undercooked pulp. Samples of the technical cellulose, received by oxidizing methods, excel sulphate cellulose in relation to yield, ability for milling, whiteness and mechanical properties (except for tear). On the set of normalized properties they approach to characteristic of kraft bleached pulp from deciduous woods and can be considered as perspective stringy half-finished for production of the paper sanitary-household and hygienic purpose.

Concentrations of extractable total phenols and tannins have been analyzed in the outer bark, inner bark, sapwood, and heart wood from logs of four conifer species, after 1 year on the ground. To estimate decay rates, initial tissue densities were compared with those after 1 and 2 years of decomposition. The four species studied, Pacific silver fir (Abiesamabilis Dougl. ex Forbs), western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and western red cedar (Thujaplicata D. Don) represent a gradient of decay resistance. Within a species, outer bark contained the greatest quantities of extractable total phenols followed by inner bark, heart wood, and sapwood. Outer barks also had the highest extractable tannin concentrations. Woody tissues contained very low concentrations of tannin compared with the barks. Total phenol concentrations were highest in the heart wood of red cedar, the most resistant, and lowest in the heart wood of silver fir, the least resistant. There was no obvious relationship between tannins, in any tissues, and the resistance gradient. Density measurements indicated minimal decay in all tissues after 1 year. At 2 years, the inner barks of Douglas-fir, western hemlock, and silver fir had decreased significantly. In general, tissues with the highest extractable phenols appear to be decomposing most slowly.

Abstract. Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While BC is highly absorbing, some organic compounds also have significant absorption, which is greater at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to direct aerosol radiative forcing. In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble organic carbon contributed to light absorption at both ultraviolet and visible wavelengths. However, a larger portion came from organic carbon that is extractable only by methanol. The spectra of water-soluble organic carbon are similar to others in the literature. We compared spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating organic aerosol with higher absorption, causing about a factor of four increase in mass-normalized absorption at visible wavelengths. A simple model suggests that, despite the absorption, both high-temperature and low-temperature carbon have negative climate forcing over a surface with average albedo.

Abstract. Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While black carbon (BC) is highly absorbing, some organic carbon (OC) also has significant absorption, especially at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to positive direct aerosol radiative forcing. Quantification of that absorption is necessary so that radiative-transfer models can evaluate the net radiative effect of OC. In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble OC contributes to light absorption at both ultraviolet and visible wavelengths. However, a larger portion of the absorption comes from OC that is extractable only by methanol. Absorption spectra of water-soluble OC are similar to literature reports. We compare spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating OC with higher absorption; changing wood temperature from a devolatilizing state of 210 °C to a near-flaming state of 360 °C causes about a factor of four increase in mass-normalized absorption at visible wavelengths. A clear-sky radiative transfer model suggests that, despite the absorption, both high-temperature and low-temperature OC result in negative top-of-atmosphere radiative forcing over a surface with an albedo of 0.19 and positive radiative forcing over bright surfaces. Unless absorption by real ambient aerosol is higher than that measured here, it probably affects global average clear-sky forcing very little, but could be important in energy balances over bright surfaces.

This study determined: (a) waste constituents remaining at long-term hazardous waste land treatment (HWLT) sites, and (b) the potential for subsequent degradation and migration of these constituents. Soils from six depths from random test pits at two oil refinery sites and a wood preserving site were evaluated for specific metals and organics. In surface soils, concentrations of organics and metals were greater than in background soils. At depths below 24-30” (60-76 cm) at the HWLT sites, PAH concentrations were below detection limits and the freon-extractable concentrations were at background. Chromium and nickel at depths below 24” (60 cm) appeared greater than background soil concentrations, but not copper, lead, and zinc concentrations. Organics in TCLP extracts of site soils indicated no PAH compounds were extracted from either weathered or non-weathered soils. In most of the site soil samples, metals in the TCLP extracts were close to or below detection limits of 0.1 mg/L. Aerobic and anaerobic microcosm studies indicated no statistically significant degradation of the PAH and freon extractables in the surface soil samples over eight months, suggesting very slow degradation of the accumulated organics following closure of an HWLT site.

Samples were collected during the winter of 1984—1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3—5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model.

Illuviated mineral horizons (Bf) from a Podzol on the Precambrian Shield, Ontario, Canada were collected, placed in columns and treated with distilled water, cation amended water, acidified water or cation and acid amended water over a 4-mo period. While the cation treatment had little effect relative to the control, the acid treatment removed large quantities of Al, Si and base cations. The source of the leached Al was primarily (~ 70%) dithionite–citrate–bicarbonate (DCB) extractable Al, apparently some form of amorphous gibbsite. Organic Al (pyrophosphate extractable) contributed only about 20%. However, even more pronounced was a major within-column migration of oxalate extractable Al–Si, perhaps allophane or imogolite, which was leached from the top of the acidified columns and precipitated below. The weathering of primary minerals and possibly interlayer Al in vermiculite contributed little to the leaching of Al from the acidified columns. Key words: Acid, weathering, Podzol, aluminum, silica

A study was conducted to determine the content and distribution of total 1.0 M NH4OAc-, 0.1 M HCl-, 1 M MgCl2-, and 0.005 M DTPA-extractable Zn in the genetic horizons of 16 soil profiles from major cacao-growing areas in Southwestern Nigeria. The content of total Zn for all the soils varied from 12 to 92 μg/g with soils derived from igneous and metamorphic rocks containing more than those of sedimentary origin. Most of the soils had the highest concentration of total Zn in the surface horizons. There was a strong association between total Zn and organic matter, total Zn and silt/clay content. The 1 M NH4OAc-, 0.1 M NCl-, 1 M MgCl2- and 0.005 M DTPA-extractable Zn in all the soils and horizons varied from 0.17 to 5.6, from 0.06 to 2.37, from 0.20 to 1.20 and from 0.022 to 1.14 μg Zn/g, respectively. The NH4OAc generally removed more Zn than the other three extractants. The amount of Zn extracted showed a general decrease with depth. A significant amount of MgCl2-extractable Zn appeared to be associated with silt content while soil pH influenced the quantity of Zn extracted by the NH4OAc method. Key words: Total Zn, NH4OAc-extractable N, HCl-extractable N, MgCl2-extractable N, DTPA-extractable Zn, soil profile

Abstract The effects of thermal compression on the organic-soluble material of a uniform wood substrate, hybrid poplar (clone OP-367), has been studied. Poplar veneers were preconditioned to 0% or 8% moisture content and subsequently hot pressed at 150°C, 200°C, and 250°C. The dichloromethane (DCM) extracts were characterized by various hyphenated analyses [gas chromatography-mass spectrometry (GC-MS), analytical pyrolysis (Py-GC-MS), electrospray ionization-mass spectrometry (ESI-MS), and gel permeation chromatography (GPC)]. The yields and composition of extractable compounds were markedly influenced by treatment at 250°C compared to those obtained at lower temperatures. Most importantly, the organic extracts contained a significant portion of lignin-derived compounds after treatment at 250°C.

La diminution des ressources pétrochimiques facilement accessibles, suscite, depuis ces dix dernières années, un intérêt croissant pour l'utilisation de matières première d'origine renouvelable. L'industrie de première transformation du bois génère chaque année des volumes importants de déchets qui sont à l'heure actuelle, soit recyclés vers d'autres filières comme la papeterie ou l'industrie des panneaux, soit utilisés comme source d'énergie, et donc vers des marchés de faible valeur ajoutée. Le projet se situe dans ce contexte de développement durable, d'économie circulaire et de valorisation des co-produits de l'industrie du bois par l'exploitation des métabolites secondaires présents dans le bois, comme les composés phénoliques, et plus précisément les flavonoïdes qui présentent en effet un intérêt dans différents domaines en raison de leurs activités biologiques. L'objectif de ce travail est de fonctionnaliser des composés accessibles et abondants afin d'obtenir des composés polyfonctionnels à propriétés 2 en 1 et pouvoir ainsi simplifier les formulations cosmétiques. La fonctionnalisation a été envisagée par deux voies : hémisynthèse chimique et/ou catalyse enzymatique. Par hemisynthèse chimique nous avons pu accéder à des composés bi-modulaires en associant un acide gras et un flavonoïde non glycosylé, en l'occurrence la catéchine. Des acylations directes au niveau des hydroxyles phénoliques de la catéchine ont été étudiées et la régiosélectivité a été demontrée par spectroscopie RMN et confirmée par modélisation moléculaire. Nous avons également préparé des composés tri-modulaires par hémisynthèse chimique en associant différents acides aminés, ainsi que des acides gras de longueur variable à la catéchine. Trois structures trimodulaires différentes ont ainsi été synthétisées, afin d'obtenir différents types de composés. Par hémisynthèse enzymatique nous avons synthétisé des composés tri-modulaires, à partir des flavonoïdes glycosylés, la rutine et la narignine, en visant le greffage d'acides gras de différentes longueurs de chaine mais cette fois ci sur la partie glycosidique des flavonoïdes. Nous avons également synthétisé des composés penta-modulaires issus du greffage d'un acide dicarboxylique sur la naringine ou la rutine. Ces composés comportent deux entités flavonoïdes greffées de part et d'autre de la chaine carbonée du diacide. A l'issue de ces synthèses, les propriétés physico-chimiques des produits ont été étudiées, notamment leur solubilité dans l'eau, leurs propriétés anti-radicalaires mais également les propriétés tensioactives. Certaines activités biologiques ont également été étudiées comme l'activité antiproliférative vis-à-vis de cellules CaCo2. Afin de comprendre l'effet de la structure des composés sur leur capacité antioxydante, des travaux de modélisation moléculaire ont été entrepris ; des corrélations entre l'activité antioxydante des composés déterminée expérimentalement et des descripteurs de réactivité chimique calculés in silico ont été recherchées
The decrease in easily accessible petrochemical resources has given over the past ten years a growing interest in the use of raw materials of renewable origin. The primary wood processing industry generates large amounts of waste each year which are currently either recycled to other sectors such as paper mills or the panel industry, or used as a source of energy, and therefore to markets with low added value. The project is situated in this context of sustainable development, circular economy and valorization of co-products of the wood industry by the exploitation of secondary metabolites present in wood, such as phenolic compounds, and more precisely flavonoids, which are indeed of interest in various fields because of their biological activities.The objective of this work is to functionalize accessible and abundant compounds in order to obtain polyfunctional compounds with 2-in-1 properties and thus be able to simplify cosmetic formulations. Functionalization has been considered by two routes: chemical hemisynthesis and/or enzymatic catalysis.By chemical hemisynthesis we were able to obtain bi-modular compounds by combining a fatty acid and a non-glycosylated flavonoid, in this case we worked with catechin. Direct acylations on the phenolic hydroxyls of catechin have been studied and the regioselectivity has been demonstrated by NMR spectroscopy and confirmed by molecular modelling. We have also obtained tri-modular compounds by chemical hemisynthesis by combining different amino acids, as well as fatty acids of variable length with catechin. Three different trimodular structures have been synthesized.By enzymatic hemisynthesis we have synthesized tri-modular compounds, from glycosylated flavonoids, rutin and narignin, aiming for the grafting of fatty acids of different chain lengths but this time on the glycosidic part of the flavonoids. We have also synthesized penta-modular compounds resulting from the grafting of a dicarboxylic acid on naringin or rutin. These compounds comprise two flavonoid entities grafted on either side of the carbon chain of the diacid.At the end of these syntheses, the physico-chemical properties of the products were studied, in particular their solubility in water, their anti-radical properties but also the surfactant properties. Some biological activities have also been studied such as antiproliferative activity against CaCo2 cells. In order to understand the effect of the structure of the compounds on their antioxidant capacity, molecular modeling work has been undertaken; correlations between the antioxidant activity of compounds determined experimentally and chemical reactivity descriptors calculated in silico were sought

The efficiency of application of the developed method of preparation of wood filler (WF) from freshly cut hardwood for wood concrete for arbolite is shown, which makes it possible to obtain lightweight concrete with compressive strength exceeding the control compositions without WF treatment, after 3 days of hardening by 2-2.7 times, and after 28 days – 2-2.9 times. The treatment of wood filler with an aqueous solution of nanosilica sol leads to blocking the release of extractable substances from the WF due to the penetration of SiO2 particles 20-40 nm in size into the vascular system of wood particles. By filling the gaps between cells, nanoparticles prevent the release of extractables into the cement system and provide cement hydration as usual.