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Pyrolysis Products (pyrolysi + products)
Selected AbstractsThermal Behaviour of Selected C10H16 MonoterpenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2006Achim Stolle Abstract The presented work investigates the thermal behaviour of selected monoterpenes under various reactor temperatures and residence times (carrier gas, reactor inserts). In addition to the analysis of the liquid products by capillary GC and GC-MS, chemical derivatisation techniques (Diels,Alder reaction, hydrogenation) were used to identify the liquid-phase products. A thermal conversion of ,-pinene (1), myrcene (2) and limonene (4) in a reaction network is presented and the experimental evidence for the formation of pyrolysis products by a biradical pathway is discussed. The reaction network was modified based on the identification of additional C10H16 terpene isomers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] The role of peptides and proteins in melanoidin formation,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2009Anna Smaniotto Abstract High-molecular-weight (HMW) coloured compounds called melanoidins are widely distributed, particularly in foods. It has been proposed that they originate through the Maillard reaction, a non-enzymatic browning reaction, due to the interaction between protein or peptide amino groups and carbohydrates. The melanoidin structure is not definitively known, and they have been generally defined as HMW nitrogen-containing brown polymers. In order to gain information on the nature of melanoidins, a simple in vitro model was chosen to investigate the products of the reactions between sugars and peptide/proteins. This approach would elucidate whether melanoidin formation is due to the binding of different sugar units to a peptide/protein or vice versa. With this aim, the reactivity of two different peptides, EPK177 and physalaemin, and a low-molecular-weight (LMW) protein, lysozyme, was tested towards different saccharides (glucose, maltotriose (MT), maltopentaose and dextran 1000) in aqueous solutions at different temperatures. The incubation mixtures were analysed at different reaction times by MALDI/MS. Furthermore, in order to verify the possible role of sugar pyrolysis products in melanoidin formation, the products arising from the thermal treatment at 200 °C of MT were incubated with lysozyme, and the reaction products were analysed by the same MS approach. The obtained results allowed the establishment of some general views: melanoidins cannot simply originate by reactions of sugar moieties with proteins. In fact, the reaction easily occurs, but it does not lead to any coloured product, as melanoidins have been described to be; melanoidins cannot originate from the thermal degradation products of glycated proteins. In fact, the thermal treatment of glycated lysozyme leads to a severe degradation of the protein with the formation of LMW species, far from the view of melanoidins as HMW compounds; experimental evidence has been gained on the melanoidin formation through reaction of intact protein with the pyrolysis products of MT. This hypothesis has been supported either from MALDI measurements or from spectroscopic data that show an absorption band in the range 300,600 nm, typical of melanoidins. Copyright © 2009 John Wiley & Sons, Ltd. [source] Synthesis of silicon nitride based ceramic nanoparticles by the pyrolysis of silazane block copolymer micellesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2006Kozo Matsumoto Abstract Diblock copolymer poly(1,1,3,N,N,-pentamethyl-3-vinylcyclodisilazane)- block- polystyrene (polyVSA- b -polySt) and triblock copolymer poly(1,1,3,N,N,-pentamethyl-3-vinylcyclodisilazane)- block- polystyrene- block -poly(1,1,3,N,N,-pentamethyl-3-vinylcyclodisilazane) (polyVSA- b -polySt- b -polyVSA), consisting of silazane and nonsilazane segments, were prepared by the living anionic polymerization of 1,1,3,N,N,-pentamethyl-3-vinylcyclodisilazane and styrene. PolyVSA- b -polySt formed micelles having a poly(1,1,3,N,N,-pentamethyl-3-vinylcyclodisilazane) (polyVSA) core in N,N -dimethylformamide, whereas polyVSA- b -polySt and polyVSA- b -polySt- b -polyVSA formed micelles having a polyVSA shell in n -heptane. The micelles with a polyVSA core were core-crosslinked by UV irradiation in the presence of diethoxyacetophenone as a photosensitizer, and the micelles with a polyVSA shell were shell-crosslinked by UV irradiation in the presence of diethoxyacetophenone and 1,6-hexanedithiol. These crosslinked micelles were pyrolyzed at 600 °C in N2 to give spherical ceramic particles. The pyrolysis process was examined by thermogravimetry and thermogravimetry/mass spectrometry. The morphologies of the particles were analyzed by atomic force microscopy and transmission electron microscopy. The chemical composition of the pyrolysis products was analyzed by X-ray fluorescence spectroscopy and Raman scattering spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4696,4707, 2006 [source] Molecular and isotopic indicators of alteration in CR chondritesMETEORITICS & PLANETARY SCIENCE, Issue 9 2006V. K. Pearson However, in contrast to other chondrite groups, the CR organic fraction is poorly characterized. The carbonaceous chondrite literature shows that relatively anhydrous thermal processing results in a condensed, poorly alkylated, O-poor macromolecular material, while for aqueous processing the converse is true. Such characteristics can be used to discern the alteration histories of the carbonaceous chondrites. We have performed bulk elemental and isotopic analysis and flash pyrolysis on four CR chondrites (Renazzo, Al Rais, Elephant Moraine [EET] 87770, and Yamato [Y-] 790112) to determine the nature of their organic component. Renazzo, Al Rais, and Y-790112 release qualitatively similar pyrolysis products, although there are some variations. Al Rais' macromolecular structure contains substantially higher relative abundances of alkylated and oxidized species and relatively lighter ,15N, suggesting that it has endured more extensive aqueous processing than the other CR chondrites. Renazzo appears relatively unprocessed, with a low degree of alkylation, a lack of detectable nitrogen-bearing components, and low methylnaphthalene ratio. EET 87770's low abundance of alkylated species suggests its macromolecular structure may be relatively condensed, with condensation potentially assisted by a period of mild thermal alteration. [source] Off-line pyrolysis and compound-specific stable carbon isotope analysis of lignin moieties: a new method for determining the fate of lignin residues in soil,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2008Jennifer A. J. Dungait Off-line pyrolysis was used to liberate lignin moieties from dung and soil and, after trimethylsilylation, the ,13C values of these derivatives were determined by gas chromatography-combustion-isotope ratio mass spectrometry. Initial ,13C values determined for 4-vinylphenol, syringol, 4-vinylguaiacol, 4-acetylsyringol, 4-vinylsyringol, 4-(2- Z -propenyl)syringol, 4-(2- E -propenyl)syringol and 4-(2-propenone)syringol pyrolysis products of the lignin polyphenol structure from C4 (,13Cbulk,=,,12.6%) and C3 (,13Cbulk,=,,30.1,) dung confirmed the robust and reproducible nature of the off-line preparation technique. C4 dung was used as a treatment in a randomised field experiment to assess the short-term sequestration of dung carbon in managed grasslands. Since lignin was on average 3.5, depleted in 13C compared with bulk dung ,13C values, this may have resulted in an under-estimation of dung C incorporation based on bulk ,13C values. Therefore, an investigation of the compound-specific ,13C values of dung-derived lignin moieties extracted from soils sampled up to 372 days was undertaken. ,13C values between lignin moieties extracted from treated and untreated soils showed that dung-derived lignin was not especially resistant to degradation and suggested that individual moieties of the lignin macromolecule must: (i) move into soil, (ii) be degraded, or (iii) be transformed diagenetically at different rates. This adds to a gathering body of evidence that lignin is not particularly stable in soils, which has considerable significance for the perceived role of different biochemical components in the cycling of C in soils. Copyright © 2008 John Wiley & Sons, Ltd. [source] The study of fluidization fast pyrolysis of straw based on the biomass entrained flow gasificationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Dong Li Abstract Straw is considered to be a kind of low heating value biomass. A new entrained flow gasification process to utilize the straw was proposed and introduced fast pyrolysis as a straw pre-treatment unit for biomass entrained flow gasification process. This study was focused on the key factors influencing on the pyrolysis products of straw and optimized the pyrolysis condition based on the analysis results to meet the needs for biomass entrained flow gasification. Experiments were carried out at the temperature ranged from 300 to 600°C. Under certain particle size and optimized fluidization flow, the maximum liquid product yield was 43.1% at the temperature of 400°C and the maximum solid product yield was 65.6% at the temperature of 300°C. The characteristics of both liquid and solid products relevant to the gasification applications were analyzed. The results showed that the energy density of the products was far more higher than that of the crude straw. Finally, an optimal pyrolysis condition was proposed, which was considered to be a suitable feedstock solution for the biomass-slurry entrained flow gasification. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||