Top PDF Preparation and reactivity of biomass derived dihydro dioxins

Preparation and reactivity of biomass derived dihydro dioxins

Preparation and reactivity of biomass derived dihydro dioxins

With a more detailed understanding of the degradation of 3 in hand, a reanalysis of the reactions reported in Tables 1 and 2 was carried out. It was confirmed that no significant degradation of 7 had occurred under the 15 minute TfOH reaction conditions (e.g. Figure S12). However, the reactions of the lignin models 5b-h did not involve extended heating times or purification of 7 by column chromatography, as was required to generate 3 from lignin (Bz- DFL). Given (i) the relative instability of 3, (ii) the observation of degradation products of 3 in the mixture of lignin-derived monomers (Figure S14) and (iii) the number of reactive groups (e.g. alcohols) present in lignin that 3 or degradation products of 3 could react with, it seems reasonable to assume that degradation of 3 has an impact on the observed yields from lignin. Rather than fight against instability of 3, it was decided to embrace its reactivity as a means of preparing more stable products. [7a-c]
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Preparation, structure and reactivity of some new types of stabilised phosphorus ylides

Preparation, structure and reactivity of some new types of stabilised phosphorus ylides

A total of twenty five (3-aminoacyl ylides derived from V-alkoxycarbonyl protected amino acids have been prepared using a carbodiimide coupling method and have been fully characterised. Upon FVP at 600 “C these readily lose PhgPO to afford protected acetylenic amino acid derivatives and twelve examples of these valuable chiral compounds have been obtained in moderate yield. By standard reactions these products have been transformed into simple chiral analogues of the important neuro transmitter GAB A in four cases. Removal of the N -protecting group in the amino acid derived ylides results in a change in pyrolysis behaviour: ethanol is eliminated rather than PhgPO to give novel cyclic stabilised ylides related in structure to the tetramic acids.
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Genetically encoded division machinery for cell free synthetic biology

Genetically encoded division machinery for cell free synthetic biology

Integrated Nanoreactor Systems: Triggering the Release and Mixing of Compounds Inside Single Vesicles.. Enzymes inside Lipid Vesicles: Preparation, Reactivity and Applic[r]

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Catalytic Effect of Metal Species on Enhancement of CO2 Gasification Reactivity of Biomass Char

Catalytic Effect of Metal Species on Enhancement of CO2 Gasification Reactivity of Biomass Char

2. 2. Pistachio Shell Char Preparation A lab- scale carbonization system was used to prepare PS char. The carbonization unit consisted of a stainless steel tube reactor with 4 cm diameter and 80 cm length, surrounded by a vertical tubular furnace. In each pyrolysis experiment, 100 g PS was loaded in the reactor and heated under a nitrogen flow of 400 ml/min at a heating rate of 15 o C/min to 900 o C. This temperature was maintained constant for 90 min. Selection of this temperature for carbonization was based on the degradation profile obtained for PS in Thermogravimetric analyzer (TGA) under N 2 as
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An Alternative Path for the Preparation of Triacetylcellulose from Unrefined Biomass

An Alternative Path for the Preparation of Triacetylcellulose from Unrefined Biomass

have important applications in our daily life such as in textile, pharmaceutical, beauty, food and packaging in- dustries. Wood pulp is main raw material for cellulose. It can also be extracted from algae, bacteria. Corn fiber, rice hulls, and wheat straw contain about 15%, 36% and 45% cellulose, respectively [23]. However, corn fiber and wheat straw were acetylated without pretreatment; the recovered yields of cellulose acetate were extremely low. When untreated corn fiber was used as the starting material only, 1.8% conversion was achieved. Based on the amount of the cellulose in corn fiber, a conversion of about 12% was achieved. Untreated wheat straw gave the lowest conversion of only 0.5%. This is somewhat surprising since wheat straw contains about 30% cellu- lose [24]. Pretreatment of the lignocellulose may be essential for making cellulose acetate. The acetylating con- version of cellulose in rice hulls, wheat straw, and corn fiber increased to about 25% for all substrates after the dilute acid pretreatment at a moderate temperature. The increase in conversion is probably due to the pretreat- ment removing hemicellulose and other acid soluble materials. The result is an increase in the relative concen- tration of cellulose in the starting substrate. It is interesting to note that after pretreatment the acetylation con- version is about the same, regardless of the starting material. This may be due to remaining cellulose having the same reactivity. It is assumed that the acetylation reaction would only work on the amorphous cellulose. This would put a theoretical conversion of cellulose to cellulose acetate at about 30%. This means that acetylation reaction of pretreated rice hulls, wheat straw, and corn fiber may be near the theoretical limit of conversion without further treatments on the cellulose to reduce its crystallinity. Since cellulose fibers are embedded with lignin, this may interfere with the acetylation reaction [8]-[12].
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Chemistry of the lanthanides with pyrazolylborate ligands.

Chemistry of the lanthanides with pyrazolylborate ligands.

electron transfer processes that are possible for the di- or zero-valent lanthanides, has allowed the preparation of compounds containing a lanthanide cation linked via an isocarbonyl bridge to a transition metal carbonylate anion. In such complexes the lanthanide acts as an electron-transfer reagent, reducing the transition metal fragment to form an anionic species, with concomitant oxidation of Ln(II) to Ln(III), and as a Lewis acid. A greater degree of backdonation occurs from the anionic transition metal centre to the carbonyl ligands, with consequent increase o f negative charge on oxygen. Reactivity has thus been observed with transition metal carbonyls such as Mn2(CO)io and Re2(CO)io in which the terminal CO groups were previously considered not basic enough to coordinate to a Lewis acidic metal centre. Andersen, for example, has reacted Yb(C5Meg)2(0Et)2 with Mn2(CO)io to afford the polymeric chain [Yb(C5Me5)2(|i- OC)3Mn(CO)2]oo and the dimeric complex [Yb(C5Me5)2(fi-OC)2Mn(CQ)3]2. Rhenium carbonyl was reported to give analogous products which were not, however, characterised by X-ray crystallography.^'^
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Biodiesel Oil Derived from Biomass Solid Waste

Biodiesel Oil Derived from Biomass Solid Waste

The jojoba raw oil is derived from the solid jojoba fruits by mechanically pressing them. After the pressing, the raw oil is extracted and the solid waste is used as animal feedstock. One of the objectives of the current work is to produce a biodiesel from a solid waste which can be used in diesel engines. The description of the chemical process is given and the physical / chemical properties of the solid and liquid fuels are highlighted.

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Rapid analysis of composition and reactivity in cellulosic biomass feedstocks with near-infrared spectroscopy

Rapid analysis of composition and reactivity in cellulosic biomass feedstocks with near-infrared spectroscopy

developed by Wolfrum et al. 150 of those samples being previously reported in that manuscript [31]. This assay included a dilute acid pretreatment (PT) for the release of carbohydrates by automated solvent extractor (ASE 350, Dionex, Sunnyvale, CA) followed by enzymatic hydrolysis (EH) of the remaining solid sample for the release of additional carbohydrates. The specific methods used from Wolfrum et al. were those developed for “optimal pretreatment conditions for screening” which held the pretreatment conditions constant [31]. The dilute acid pretreatment used a constant temperature of 130°C for 7 min, 3.0 g sample, and 30 mL of a 1% sulfuric acid solu- tion. The enzymatic hydrolysis method was similar to the NREL LAP, “Enzymatic Hydrolysis of Lignocellulosic Biomass” [39]. Both release and yield measurements reflect the sum of each carbohydrate obtained after the combined or total assay (PT plus EH). Glucose and xylose release, as a result of pretreatment and subsequent enzym- atic hydrolysis, was defined as the mass of carbohydrate re- leased per unit of dry biomass. The xylan yield was defined as the ratio of xylose release to the xylan mass fraction in the feedstock, with anhydro correction for conversion of xylose to xylan. The glucan yield was defined as the ratio of glucose release to the glucose and sucrose mass fraction in the feedstock, with anhydro correction for conversion of glucose to glucan. A more detailed description of these calculations and the assumptions inherent in them is provided by Wolfrum et al. [31].
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A laboratory-scale pretreatment and hydrolysis assay for determination of reactivity in cellulosic biomass feedstocks

A laboratory-scale pretreatment and hydrolysis assay for determination of reactivity in cellulosic biomass feedstocks

The results of the variable temperature pretreatment ex- periments are summarized in Figures 2, 3, 4, and 5. The total (monomeric and oligomeric) xylan yields from pre- treatment alone and from pretreatment followed by en- zymatic hydrolysis for four different biomass feedstocks (corn stover (a), poplar (b), switchgrass (c), and sorghum (d)) across a range of pretreatment temperatures are shown in Figure 2. The smooth curves through the data are cubic splines added to guide the eye of the reader; they do not represent a theoretical model. There are a large number of points at 130°C for the corn stover plot (Figure 2a). These are the method controls, shown as a time series in Figure 1.
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The roles of volatile organic compound deposition and oxidation mechanisms in determining secondary organic aerosol production: a global perspective using the UKCA chemistry–climate model (vn8.4)

The roles of volatile organic compound deposition and oxidation mechanisms in determining secondary organic aerosol production: a global perspective using the UKCA chemistry–climate model (vn8.4)

The diversity in model treatment of SOA formation is partially due to the myriad of unique organic molecules in the atmosphere, a small fraction of which have been mea- sured (Goldstein and Galbally, 2007). In the simplest of schemes, production of SOA is calculated as a function of emissions, hence SOA is “emitted” as opposed to being formed in the atmosphere (Tsigaridis et al., 2014). In cases where gas-phase oxidation of SOA precursors is treated, sev- eral simplifications are commonly made. For example, bio- genic VOCs, such as isoprene and monoterpenes, are known to have multi-generational oxidation mechanisms, but the mechanisms are often reduced to less than two reaction steps when implemented in global models (Chung and Seinfeld, 2002; Heald et al., 2011; Scott et al., 2014, 2015). Similarly, multi-generational oxidation mechanisms of aromatic com- pounds are often represented by less than two reaction steps (Tsigaridis and Kanakidou, 2003; Heald et al., 2011). Gas- phase oxidation schemes can also be simplified by group- ing organic compounds together (i.e. “lumping”). In some schemes, organic compounds are lumped according to emis- sions types, anthropogenic or biomass burning (Spracklen et al., 2011; Hodzic et al., 2016), whereas in others they are grouped according to volatility (Donahue et al., 2006, 2011). By lumping organic species together, chemical ageing can be accounted for, even if the exact mechanism is not known. However, in grouping species together, molecular informa- tion is lost and therefore it is challenging to select the ap- propriate reaction coefficients and SOA yields from labo-
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Agricultural waste pulverised biomass: lean flammability and flame speed as a measure of reactivity

Agricultural waste pulverised biomass: lean flammability and flame speed as a measure of reactivity

Pulverised biomass flames propagate by thermal transfer of heat by conduction and radiation from the reaction zone into the advancing unburned biomass dust air turbulent cloud. The biomass powder undergoes de-volatilisation as the particle moves towards the reaction zone and biomass powders release typically 80% of their mass as volatile material when they are heated to around 300 o C, as will be shown for the present agricultural biomass. In comparison, coal releases much less volatiles, at typically 30% by mass and the assumption that these are hydrocarbons is often made. It is shown in the analysis of the present biomass that the much larger volatile emissions from biomass heating cannot be hydrocarbons and must be a mixture of CO, hydrogen and some hydrocarbons. It is also possible that under the rapid heating in a flame front more of the biomass is converted into volatiles. Sattar et al. (2012a, b) have found no evidence for char to remain after biomass dust explosions in the ISO 1 m 3 explosion vessel and this indicates that all the biomass is converted into volatile products during the rapid heating in flame front.
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Bioethanol Production from Cellulose and Biomass Derived Syngas

Bioethanol Production from Cellulose and Biomass Derived Syngas

Next, we look into these two approaches in more details. The first step in the biological approach is the pretreatment of the biomass raw material. The bulk of plant material is lignocelluloses. The cellulose is protected from hydrolysis by lignin. Therefore the structure has to be broken to free the cellulose. This can be done by various physical and chemical methods. The Organosolv and Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL) is highly effective in terms of cellulose conversion for feedstocks with high lignin content [6]. A mechanical alternative is steam explosion which involves subjecting the biomass to high-pressure steam for a certain period of time and then explosively release the pressure.
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Gas-Insulated Gasifier for Biomass Derived Producer Gas.

Gas-Insulated Gasifier for Biomass Derived Producer Gas.

Gasification as a field of study is complex and is not entirely understood (Reed 1988). Estimating gasifier effectiveness on various solid fuel sources is generally done by direct research. Current research in biomass gasification revolves around testing different biomass using commercial gasifiers or custom built gasifiers. Recent research is trending towards using commercial gasifiers to test biomass for producer gas composition, which can be expensive in investment cost, labor and maintenance (Gautam et al., 2011; Wei et al., 2009). Meanwhile research in developing a gasifier capable of utilizing multiple types of biomass with varying physical characteristics has stagnated since the research of Reed (1988) and Kaupp and Gross (1984).
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Preparation and characterization of LaCoO3

Preparation and characterization of LaCoO3

This catalyst ,lanthanum cobaltat (LaCoO3) was prepared by the proper method in the analysis laboratory of Tabriz Oil .The first materials were chosen through calcination operation and [r]

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Physicochemical Characterization of Biomass Residue–Derived Biochars in Vietnam

Physicochemical Characterization of Biomass Residue–Derived Biochars in Vietnam

assessment of the suitability of the different BCs match to these properties.. Acacia wood, rice husk and bamboo), produced using a pyrolysis approach indicated. 487[r]

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A novel GH10 xylanase from Penicillium sp. accelerates saccharification of alkaline-pretreated bagasse by an enzyme from recombinant Trichoderma reesei expressing Aspergillus β-glucosidase

A novel GH10 xylanase from Penicillium sp. accelerates saccharification of alkaline-pretreated bagasse by an enzyme from recombinant Trichoderma reesei expressing Aspergillus β-glucosidase

three rounds of mutagenesis of the wild-type strain QM6a [10]. This strain is capable of cellulase and hemicellulase production on glucose-containing media because of muta- tions in cre1 (encoding the carbon catabolite repressor protein) [11]. In Japan, T. reesei strain PC-3-7 was devel- oped following several rounds of random mutagenesis from T. reesei QM9414, a mutant with enhanced cellulase activity derived from QM6a [12–15]. The PC-3-7 strain showed twice as much cellulase activity as QM9414 when induced by α-sophorose, because of mutations in cre1 and bgl2 (encoding intracellular β-glucosidase) [15, 16]. More- over, Denton et al. have reported that disruption of cre2, a gene encoding a deubiquitinating enzyme, in T. reesei led to increase a threefold increase in cellulase activity when induced by microcrystalline cellulose [17], and Zhang et al. have reported that disruption of the alkaline serine protease in T. reesei resulted in enhancement of heterolo- gous protein productivity [18]. As a result of such devel- opments, it has been reported that Trichoderma mutants produce enzymes up to 100  g/L in controlled fermenter cultivations [19], thus making it possible to greatly reduce the cost of saccharifying enzymes.
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Dioxins in organic eggs: a review

Dioxins in organic eggs: a review

Sources of dioxins include feed, worms, insects, grass, herbs and soil (Kijlstra, 2004). Compared with hens on conventional and free-range farms, organic hens make more use of these sources because they spend more time in the outdoor run, which may lead to an increase in the dioxin content of their eggs. This suggests that management interventions can help to reduce the dioxin level in organic eggs. In a meeting of researchers and farmers several measures were proposed. The first measure that was proposed aims to reduce dioxin intake by shortening the time hens spend ranging in the outdoor run. The second measure is to reduce the size of the outdoor run. Also covering the soil in the outdoor run can possibly reduce dioxin intake. Finally, improving the general health status may prevent the hens from ingesting soil.
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CO 2Gasification Reactivity of Chars Derived From Zhundong Coal

CO 2Gasification Reactivity of Chars Derived From Zhundong Coal

By increasing gasification temperature, R-char is quite reactive to yield high carbon conversions in reasonable time (51.59% at 1123 K/11 min), while almost complete conversion is achi[r]

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CO2 Biomass Fluidized Gasification. Thermodynamic and Reactivity Studies.

CO2 Biomass Fluidized Gasification. Thermodynamic and Reactivity Studies.

the present study. Three biomasses were involved: Costa Rica broza or coffee pulp, provided by ICAFE, followed by two other wood waste biomasses feedstock: wood pellets, provided by CANMET Energy, and bark, provided by KMW Energy. The approach considered includes both a thermodynamic analysis, as well as reactivity studies, in a CREC Riser Simulator unit. This is a twin fluidized bed gasifier unit, which operates very close to the conditions found in the industrial riser unit. This study shows that a thermodynamic equilibrium model is valuable for performance gasifier predictions while co-feeding CO 2 . This study also shows the
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Conversion of biomass-derived oligosaccharides into lipids

Conversion of biomass-derived oligosaccharides into lipids

Because the hydrolytic enzymes were predominantly located in the cytoplasm, the lysis supernatant samples were separated by native PAGE for in-gel β-glucosidase activity detection. C. curvatus cells were cultivated for 12 h on glucose, cellobiose and oligocelluloses, respectively, and equal amounts of wet cells were applied for lysis supernatant preparation. Total aryl-β-glucosidase ac- tivities of these samples are shown in Figure 5A. When aryl-β-glucosidase activity of the sample prepared from oligocelluloses was set as 100%, activities of samples prepared from cellobiose and glucose were 57.3% and 8.7%, respectively. The fact that aryl-β-glucosidase ac- tivities were significantly higher in cells cultured in the presence of oligocelluloses or cellobiose suggested that those glycosidic enzymes were induced by oligocellu- loses. Protein staining of the native PAGE gel with Coomassie brilliant blue R-250 found little differences among samples prepared from these three types of car- bon sources (Figure 5B). However, when the gel was treated with MUG and then visualized under UV light at 365 nm, at least four bands appeared. The significant
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