Search results for "Pyrolysi"
showing 10 items of 170 documents
Pyrolytic behavior of lignocellulosic-based polysaccharides
2018
The thermochemical behavior of cellulose, glucomannan, and xylan was investigated by pyrolysis–gas chromatographymass spectrometry (Py-GC/MS). In each case, major GC-amenable condensable products were classified into several compound groups, and the formation of these monomer-related fragments from the model substance samples was determined at 500, 600, and 700 C with a residence time of 5 s and 20 s. The results revealed that despite some general formation trends, no compound group was selectively formed at certain temperatures. Of the 11 product groups, the primary ones, including lactone, furan, and cyclopentenone derivatives, accounted for 72–85% (from cellulose), 86–90% (from glucomann…
Precursor Polymers for the Carbon Coating of Au@ZnO Multipods for Application as Active Material in Lithium-Ion Batteries
2014
The synthesis of statistical and block copolymers based on polyacrylonitrile, as a source for carbonaceous materials, and thiol-containing repeating units as inorganic nanoparticle anchoring groups is reported. These polymers are used to coat Au@ZnO multipod heteroparticles with polymer brushes. IR spectroscopy and transmission electron microscopy prove the successful binding of the polymer onto the inorganic nanostructures. Thermogravimetric analysis is applied to compare the binding ability of the block and statistical copolymers. Subsequently, the polymer coating is transformed into a carbonaceous (partially graphitic) coating by pyrolysis. The obtained carbon coating is characterized by…
Pyrolysis of vegetable oil soaps—Palm, olive, rapeseed and castor oils
2011
Abstract Saponified, palm, olive, rapeseed and castor oils were pyrolysed (at 750 °C for 20 s) by pyrolysis gas chromatography with mass selective and flame ionisation detection (Py-GC/MSD and FID) to clarify their thermochemical behaviours. The liquefiable compounds recovered from palm, olive and rapeseed oils mainly contained linear alkenes (up to C 19 ) and alkanes (up to C 17 ), both similar to those found in gasoline (C 4 –C 10 ) and diesel fuel (C 11 –C 22 ) boiling range fractions of petroleum, whereas in the case of castor oil a significant amount of undesired oxygen-containing products (e.g., ketones and phenols) were formed. The obtained data on reaction mechanisms can also be uti…
A LAB-SCALE MICROWAVE SYSTEM FOR EXPERIMENTS OF HIGH TEMPERATURE WASTE PYROLYSIS
2016
The reactor designed and assembled at Università degli Studi di Palermo - presented here - was conceived to explore high unit power input, high temperature reductive processes. Its main field of use therefore is likely to be the destruction of liquid waste fed as an aerosol; or of VOCs; or of granular waste making a fluidized bed. If required, a 3 - phase system including a solid catalyst could also be set up. These waste should be free of low - melting or boiling metals. Incidentally, a literature review shows that the compounds taken as benchmark in thermal VOC destruction are trichloroethylene, benzene and toluene. At lower unit power rates this MW - based system lends itself also to rec…
Generation of hexahydroazulenes
2009
(Z)-Cyclodec-1-en-6-yne (3) generates three conjugated hexahydroazulenes 3→1k→1c, 1l under FVP conditions, whereas flash vacuum pyrolysis (FVP) of cyclodecyne (2) leads to 1,2,9-decatriene (9). We attribute the different thermal behavior of 2 (ring opening) and 3 (ring closure) to different transannular interactions. Altogether 22 constitutional isomers of hexahydroazulene should exist; three new isomers (1k, 1l, and 1m) are presented here, ten were described earlier, but the reinvestigation of the dehydration route of bicyclic alcohol 11 showed that one of the ten structures has to be revised.
Thermal rearrangements of 1,2-dialkoxybenzenes by flash vacuum pyrolysis
1995
Flash vacuum pyrolysis of 1,2-dialkoxybenzenes 1a-c leads to the liberation of alkanes from the interacting side chains. A rearrangement of the skeleton yields the o-hydroxy carbonyl compounds 2 and 4. The generation of phenol 3 can be rationalized by a decarbonylation. The latter reaction is the sole process which can be observed for the bicyclic starting compound 9.
Method development of levoglucosenone analysis by UHPLC-UV-MS in fast pyrolysis samples and aspects of its degradation in aqueous samples
2020
Levoglucosenone ((1S,5R)-6,8-dioxabicyclo[3.2.1]oct-2-en-4-one or LGO; CAS number: 37112-31-5) is an extensively studied biomass based chemical and its potential applications in organic synthesis, as well as in the extraction of various natural substances, have been established; therefore developing dependable, yet fast and simple analytical methods for determining LGO in the products of thermochemical biomass processing is of great importance. In this work different UHPLC methods have been developed and compared for the determination of LGO in wood pyrolysis products. In addition to UV detection, LGO determination conditions by single quadrupole mass spectrometry have been adjusted with an…
Study of the thermal behaviour of ordered bimetallic EDTA complexes
1986
Abstract The study of the thermal behaviour of a family of isostructural ordered bimetallic MM'(EDTA)·6H 2 O complexes has been performed using TG and DTA. Formal kinetic analysis of the dehydration step has been approached using non-isothermal procedures. The resulting correlation among the calculated E a values and the cationic sizes implies a common dehydration mechanism. Copper-containing complexes show distinctive behaviour during the ligand pyrolysis processes. A mechanistic interpretation involving formation of Cu(I) and Cu(0) intermediates is furnished. The evolution of the inorganic residues in systems containing both Co and Ni is especially considered given the interest in the (Co…
Assessment of bio-combustibles production via slow pyrolysis of wine industry residues
2018
With the aim of evaluating the potential production of high energy solid and liquid bio-fuels, a laboratory scale fixed bed reactor (FBR) derived from the standard Gray-King (GK) assay test on coal was used to carry out fixed bed pyrolysis experiments on wine industry by-products. The present study provides results on the pyrolysis of grape marc, residual from wine-making process, consisting of 50% by weight of grape seeds and 50% by weight of grape skins, at temperature between 150 and 500 °C, holding time of 30 minutes. Pyrolysis mass yields of solid (char) and liquid (tar) products and their corresponding energy properties, as a function of reaction temperature, are reported and discusse…
High-resolution pyrolysis–gas chromatography with a movable reaction zone
1997
Abstract A new device was constructed for pyrolysis–gas chromatography and it was laboratory tested. The device enables the thermal degradation of polymers inside a capillary pre-column and transfer of the reaction zone into a column oven. The pyrolysis procedure described protects the thermally sensitive compounds prior to pyrolysis, prevents the process of irreversible condensation of high-boiling pyrolysis products during the chromatographic process and eliminates extracolumn effects on the peak broadening.