scholarly journals Representative model compounds for understanding the pyrolytic behavior of pre-oxidized β-ether-type lignin

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6989-7008
Author(s):  
Shuyun Liu ◽  
Weikun Jiang ◽  
Bo Jin ◽  
Yu Liu ◽  
Lucian A. Lucia
Keyword(s):  
Simultaneous Thermal Analysis ◽  
Product Distribution ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Och3 Group ◽  
Primary Products ◽  
Bridge Structures ◽  
Secondary Reactions ◽  
Representative Model

To achieve a better understanding of the pyrolysis behavior of pre-oxidized β-ether-type lignin, three Cα=O type dimers with different substituent groups on the aromatic ring were synthesized and analyzed by a simultaneous thermal analysis instrument (STA), in-situ Fourier transform infrared spectroscopy (in-situ FTIR), and pyrolysis-gas chromatography/ mass spectrometry (Py-GC/MS). The results showed that major primary pyrolysis reactions of Cα=O type models normally occurred at 200 to 400 °C, and connecting bridge structures of models were completely destroyed, causing the emission of abundant volatiles. Substituent groups of aromatic rings played direct roles in thermal stability of models, volatiles emission, product characteristics, and secondary reaction pathways of major primary products. Particularly, the aryl–OCH3 group clearly enhanced the reactivity of intramolecular linkages and was an important active functional group for secondary reactions. As major primary products and intermediates, guaiacol and 2-methoxy-benzaldehyde were formed via the cleavage of Cα–O and Cα–Cβ bonds and could also be converted into phenol, benzaldehyde, and 2-methylphenol via rearrangement of aryl–OCH3 into an aryl–CH3 group or –OCH3 group removal. Oxidization of benzylic alcohol to benzylic ketone not only simplified depolymerization pathways, but also resulted in better selectivity of phenolic monomers and a predictable product distribution.

Naphthalene and Alkyl Naphthalene from Catalytic Fast Pyrolysis of Biomass Over ZSM-5 Aggregates

2020 ◽  
Vol 14 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Fanjun Meng ◽  
Qiaoyan Shang ◽  
Dongliang Hua ◽  
Lei Chen ◽  
Laizhi Sun ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fast Pyrolysis ◽  
Product Distribution ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Organic Templates ◽  
Pyrolysis Of Biomass ◽  
Pyrolytic Product

Seed-induced synthesis of ZSM-5 aggregates was carried out without organic templates. The prepared ZSM-5 aggregates were used upgrading polar sawdust-derived pyrolytic vapors for the selective production of naphthalene and alkyl naphthalene. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were conducted to analyze the pyrolytic product distribution and evaluate the catalyst performance. Due to the mesopores and proper acidities of ZSM-5 aggregates, the yield of naphthalene and methylnaphthalene over ZSM-5 aggregates were 36.0 and 123.7 mg/g, which were 2.7 and 2.6 times of those respectively over the commercial ZSM-5. The total selectivities of naphthalene and alkyl naphthalene could reach 61.56%.

Analytical Fast Pyrolysis of Glucose, Cellubiose and Cellulose: Comparison of the Pyrolytic Product Distribution

2013 ◽  
Vol 805-806 ◽  
pp. 186-190
Author(s):  
Hang Tao Liao ◽  
Yang Zhang ◽  
Qiang Lu ◽  
Chang Qing Dong
Keyword(s):  
Mass Spectrometry ◽  
Fast Pyrolysis ◽  
Product Distribution ◽  
Gas Chromatography Mass Spectrometry ◽  
Analytical Pyrolysis ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Pyrolytic Products ◽  
Fragmentation Reactions ◽  
Pyrolytic Product

Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was employed for the fast pyrolysis of glucose, cellubiose and cellulose in this study. The pyrolytic products from the three glucose-based materials were determined and compared to reveal the distribution differences. The results indicated that fast pyrolysis of the three materials obtained similar pyrolytic products, including the anhydrosugars, furans, linear carbonyls and cyclopentanones, but the distribution of the pyrolytic products differed from each other. The cellulose formed more anhydrosugars, but less carbonyls and furans than the glucose and cellubiose. The glycosidic bond of the cellubiose and cellulose would favor the pyrolytic depolymerization reactions to form various anhydrosugars, while inhibit the pyrolytic fragmentation reactions to produce linear carbonyls.

Production of Phenolic Compounds from Low Temperature Catalytic Fast Pyrolysis of Biomass with Activated Carbon

2014 ◽  
Vol 541-542 ◽  
pp. 190-194 ◽  
Author(s):  
Zhi Bo Zhang ◽  
Xiao Ning Ye ◽  
Qiang Lu ◽  
Chang Qing Dong ◽  
Yong Qian Liu
Keyword(s):  
Activated Carbon ◽  
Phenolic Compounds ◽  
Fast Pyrolysis ◽  
Product Distribution ◽  
Catalytic Performance ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Process ◽  
Pyrolysis Gas ◽  
Catalytic Fast Pyrolysis ◽  
Pyrolysis Of Biomass

Activated carbon (AC) was reported as a promising catalyst to selectively produce phenolic compounds from biomass using the micro-wave assisted catalytic pyrolysis technique. In order to evaluate the catalytic performance of the AC under the traditional fast pyrolysis process, analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique was applied for the catalytic fast pyrolysis of biomass mixed with the AC. Polar wood was selected as the feedstock, and experiments were conducted to reveal the AC-catalyzed poplar wood pyrolysis behavior and product distribution. The results indicated that the AC was also effective for the phenolics production in the traditional fast pyrolysis process at 350 °C. It could promote the formation of phenolic compounds, and inhibit most of the other pyrolytic products. The maximal phenolics yield was obtained at the biomass to catalyst ratio of 1:4, with the peak area% over 50%.

Kinetics and modelling of heptane steam-cracking

2014 ◽  
Vol 68 (12) ◽  
Author(s):  
Natália Olahová ◽  
Martin Bajus ◽  
Elena Hájeková ◽  
Lukáš Šugár ◽  
Jozef Markoš
Keyword(s):  
Flow Reactor ◽  
Frequency Factor ◽  
Product Distribution ◽  
Reaction Scheme ◽  
Reaction Products ◽  
Primary Products ◽  
Molecular Reaction ◽  
Secondary Reactions ◽  
Steam Cracking ◽  
Good Agreement

AbstractThe kinetics and product distribution during the cracking of heptane in the presence of steam were investigated. The experiments were performed in a flow reactor under atmospheric pressure in a temperature range of 680–760°C with a mass ratio of steam to heptane of 3: 1. The overall decomposition of heptane is represented by a first-order reaction with activation energy of 249.1 kJ mol−1 and a frequency factor of 3.13 × 1013 s−1. The reaction products were analysed using gas chromatography, the main product being ethylene. The molecular reaction scheme, which consists of a primary reaction and 24 secondary reactions between primary products, was used for modelling the experimental product yields. The yields of ethylene and hydrogen were in good agreement; however the experimental yields of propylene were higher than the predicted yields.

Production of Phenolic-Rich Bio-Oil from Catalytic Fast Pyrolysis of Biomass Over Tailored Fe-Based Catalysts

2020 ◽  
Vol 14 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Shuangxia Yang ◽  
Xiaodong Zhang ◽  
Feixia Yang ◽  
Baofeng Zhao ◽  
Lei Chen ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Pyrolysis Temperature ◽  
Fast Pyrolysis ◽  
Product Distribution ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Bio Oil ◽  
Aldehydes And Ketones ◽  
Biomass Ratio ◽  
Pyrolysis Of Biomass

The objective of this study is to catalytically upgrade fast pyrolysis vapors of sawdust using various Fe-based catalysts for producing phenolic-rich bio-oil by analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique. A variety of parameters, including support characteristic, calcination temperature, pyrolysis temperature, as well as the catalyst-to-biomass ratio during the pyrolysis process were evaluated for their effects on product distribution of bio-oil. GC-MS analysis showed that compared to Fe–Mg and Fe–Al catalysts, the developed Fe–Ca catalyst significantly promoted the formation of phenols and its derivatives. The phenolic concentration declined with increasing calcination temperature and pyrolysis temperature, while increased monotonically along with increasing catalyst-to-biomass ratio. The phenolics concentration was high upto 81% (peak area) under optimum conditions of calcination temperature of 500 °C, pyrolysis temperature of 600 °C and catalyst-to-biomass ratio of 10. At higher catalyst-to-biomass ratio of 20, phenolics (88.03% in peak area) and hydrocarbons (including 7.86% of aromatics and 4.1% aliphatics) were the only two components that can be detected, with all the acids, aldehydes and ketones completely eliminated. This indicated the excellent capability of developed Fe–Ca catalyst in promoting the decomposition of lignin in biomass to generate phenolic compounds and meanwhile inhibiting the devolatilization of holocellulose.

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