Search results for "Pyrolysis"

Obtaining lignocellulosic biomass-based catalysts and their catalytic activity in cellobiose hydrolysis and acetic acid esterification reactions

2021

Global challenges prompt the world to modify its strategies and shift from a fossil-fuel-based economy to a bio-resource-based one with the production of renewable biomass chemicals. Different processes exist that allow the transformation of raw biomass into desirable bio-based products and/or energy. In this work different biochars that were obtained as a by-product from birch chip fast pyrolysis and carbonization were used as is or chemically/physically treated. These sulfonated carbon catalysts were compared to a commercially available sulfonated styrene-divinylbenzene macroreticular resin (Dowex 50W X8). Characterisation (water content and pH value, FTIR, base titration, element analysi…

Various types of polysiloxanes studied by positron annihilation lifetime spectroscopy

2014

Abstract In the work, linear poly(vinylsiloxanes) with regular distributions of vinyl groups along chains, the networks obtained by their hydrosilylation with various hydrogensiloxanes, products of pyrolysis of such networks as well as the networks prepared via reaction of low-molecular siloxanes have been studied by positron anihilation lifetime spectroscopy (PALS). Based on free volume sizes determined by this method, relations between cross-link densities in the investigated systems have been established. They have been compared with the results of swelling experiments conducted in the work and to efficiency of cross-linking reaction evaluated in our previous FTIR investigations of the s…

PYROLYSIS-MASS SPECTROMETRY OF TRUXILLIC AND TRUXINIC POLYAMIDES AND RELATED COPOLYAMIDES

1977

Mechanisms of Organic Coating on the Surface of a Poplar Biochar

2017

Background: Recent studies highlighted that biochar efficiency to improve soil fertility is enhanced after it is blended with fresh organic materials. It was suggested that organic coating of inner-porous biochar surfaces acts as a kind of “glue” for plant-nutrients, thereby allowing their slow release towards plant-roots and/or microorganisms. Objective: The aim of the present study is to improve the understanding of the nature of the interactions between fresh organic matter and a poplar biochar. Method: Two fluorinated organic models were used as target molecules in order to apply heteronuclear (i.e. 19F) fast field cycling (FFC) NMR relaxometry. Results: The results suggest that organic…

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…

Comparison of photodiode array, evaporative light scattering, and single-quadrupole mass spectrometric detection methods for the UPLC analysis of pyr…

2017

ABSTRACTIt is important to analyze pyrolysis liquids to evaluate the yield of valuable products as well as unfavorable by-products. This work focuses on choosing detectors for reversed-phase ultra high-performance liquid chromatography analysis of pyrolysis liquids. The linearity, sensitivity, precision, and recovery of photodiode array (PDA) detector, single-quadrupole mass spectrometer (MS), and evaporative light scattering (ELS) detector were compared for the quantitative determination of several typical compounds found in pyrolysis liquids. PDA and MS detectors were found to be suitable for the quantification of furans and phenol derivatives (furfural, vanillin, syringol), but sugars an…

Pyrolytic formation of polyaromatic hydrocarbons from steroid hormones

2011

Author's version of an article published in Food Chemisty, 124 (4), 1466-1472. Also available from the publisher: hhtp://dx.doi.org/10.1016/j.foodchem.2010.07.109 Four steroid hormones, namely androsterone, cholesterol, estrone and estradiol, have been pyrolysed at 300, 400 and 500 °C and the pyrolysates from these have been analysed by GC-MS. The results indicate that these formed different products under the pyrolysis and most of them evolved into polycyclic aromatic hydrocarbons during their residence in the pyrolysis chamber at high temperatures. The products from the pyrolysates, at all temperatures, were analysed for similarities and differences using multivariate data analysis. The p…

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.

Thermal degradation of novolac resins by pyrolysis-gas chromatography with a movable reaction zone

1999

Abstract A previously described, a pyrolysis device with a movable reaction zone was used in the present work for thermal degradation of novolac resins. The products of thermal reactions were analysed by pyrolysis–GC. Owing to the heating of reaction zone to the maximal temperature of the chromatographic column, the high boiling pyrolysis products could be analysed. Bisphenols and trisphenols with aromatic rings coupled by methylene bridges and its methyl derivatives have been found among the compounds. The structure of the heavy pyrolysis products has been confirmed using GC–MS.

Characterization of high molecular mass material in ECF and TCF bleaching liquors by Py-GC/MS with and without TMAH methylation

2006

Abstract High molecular weight (HMW) fractions (MW > 1000) of effluents were obtained by ultrafiltration of elemental chlorine-free (ECF) bleaching (O-D-EOP-D-ED) and totally chlorine-free (TCF) bleaching (O-Z-Q-P-Z-Q-P-P) liquors of softwood (Pinus sylvestris) pulp. The fractions were studied by analytical pyrolysis coupled to gas chromatography/mass spectrometry (Py-GC/MS) with and without TMAH (tetramethyl ammonium hydroxide) derivatization. The pyrograms showed a number of pyrolysis products mainly derived from lignin and carbohydrates. The comparison of 4-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) lignin units in both bleaching effluents showed that the G unit content was clearly…