基于Py-GC/MS研究热解反应中自由基的捕获反应

doi:10.11949/0438-1157.20210907

摘要/Abstract

摘要：

在500℃下对类煤模型化合物1-萘甲醇与同位素示踪剂的共热解进行了机理研究。利用Py-GC/MS进行快速产物检测，同时联合自由基捕获剂来推断自由基的反应过程。结果表明，在500℃和0.2 min的条件下，1-萘甲醇的热解产物相对单一，但是自由基反应的引发、交换和湮灭极其快速，现有检测方法是对某一时间节点的平衡反应结果的分析。通过D₂O和H₂¹⁸O同位素示踪，成功捕获到了自由基交换后的D取代产物和¹⁸O取代产物。揭示了1-萘甲醇经过1-萘甲基自由基转化为1-萘甲醛的转化过程，发现萘环上的取代基在1-萘甲醇的热解过程中起着重要作用。同时对自由基及产物进行了定性和半定量分析，发现在加入自由基捕获剂后产物的丰度较之前降低了一个数量级，说明了自由基捕获剂抑制了产物的生成。

关键词: 热解, 模型, 热解气相色谱质谱联用, 自由基, 自由基捕获剂

Abstract:

In this study, the mechanism of co-pyrolysis of the coal-like model compound 1-naphthyl methanol and isotope tracer was studied at 500℃. The pyrolysis process is carried out by using a thermal cracker, and then mass spectrometry is used to detect the product to infer the reaction and change behavior of free radicals. The results show that the free radical reaction dominates the pyrolysis process at 500℃, and this behavior is more pronounced. Through the isotope labeling method and spin trapping technology, the hydrogen radicals were successfully captured. The transformation process of the conversion of 1-naphthyl methanol to 1-naphthaldehyde is revealed, and it is found that the substituents on the benzene ring play an important role in the thermal process of 1-naphthyl methanol. At the same time, qualitative and semi-quantitative analysis of free radicals and products was carried out, and it was found that the abundance of products after the addition of free radical traps was an order of magnitude lower than before, indicating that the free radical traps inhibited the formation of products.

Key words: pyrolysis, model, Py-GC/MS, free radicals, radical scavenger

中图分类号:

TQ 028.8

罗紫藤, 周秋成, 王雨露, 席引尚, 周安宁, 陈福欣. 基于Py-GC/MS研究热解反应中自由基的捕获反应[J]. 化工学报, 2022, 73(2): 914-922.

Ziteng LUO, Qiucheng ZHOU, Yulu WANG, Yinshang XI, Anning ZHOU, Fuxin CHEN. Study on capture reaction of free radicals in pyrolysis reaction based on Py-GC/MS[J]. CIESC Journal, 2022, 73(2): 914-922.

图/表 10

表1 主要实验仪器与设备

Table 1 The main experimental instruments and equipments

仪器与设备	型号	生产厂家
电子天平	CPA225D	赛多利斯科学仪器（北京）有限公司
气相色谱-质谱联用仪	7890A/5975C型	美国Agilent公司
热裂解仪	Py-2020is	日本FRONTIER LAB

表2 实验样品

Table 2 Experimental sample

模型化合物	加入量/mg	同位素示踪剂	加入量/μl	自由基捕获剂	加入量/mg
1-萘甲醇	0.01	水	2	—	—
		D₂O	2	—	—
		H₂¹⁸O	2	—	—
		水	2	TCNQ	0.01
		D₂O	2	TCNQ	0.01
		H₂¹⁸O	2	TCNQ	0.01

图1 不同温度下1-萘甲醇与水共热解TIC图

Fig.1 TiC diagram of 1-naphthyl methanol co-pyrolysis with water at different temperatures

表3 1-萘甲醇和H2O的主要热解产物

Table 3 The main pyrolysis product of 1-naphthyl methanol and H2O

序号	热解产物	保留时间/min
1	萘	5.581
2	1-甲基萘	6.522
3	1-萘甲醛	7.826
4	1-萘甲醇	8.260
5	9-芴酮	9.238
6	9-methylene-9H-fluorene	9.538

图2 不同处理条件下的1-萘甲醇热解TIC图

Fig.2 TIC of 1-naphthyl methanol pyrolysis under different treatment conditions

图3 热解质谱图：标准质谱与同位素质谱

Fig.3 Pyrolysis mass spectrometry: standard mass spectrometry and isotopic mass spectrometry

图4 不同处理条件下1-萘甲醇热解TIC图

Fig.4 TIC of 1-naphthyl methanol pyrolysis under different treatment conditions

图5 2-苯基丙二腈热解质谱图：标准质谱与同位素标记质谱

Fig.5 Pyrolysis mass spectrometry of 2-phenylmalononitrile: standard mass spectrometry and isotopic mass spectrometry

图6 TCNQ的自由基捕获示意图

Fig.6 Schematic diagram of free radical capture of TCNQ

图7 1-萘甲醇热解机理

Fig.7 Pyrolysis mechanism diagram of 1-naphthyl methanol

参考文献 35

1	刘俊杰, 武瑞瑞, 袁悦, 等. 煤热解工艺现状及发展趋势[J]. 化工技术与开发, 2020, 49(12): 23-27.
	Liu J J, Wu R R, Yuan Y, et al. Current status and development trend of coal pyrolysis process[J]. Technology & Development of Chemical Industry, 2020, 49(12): 23-27.
2	吴志强, 张博, 杨伯伦. 生物质化学链转化技术研究进展[J]. 化工学报, 2019, 70(8): 2835-2853.
	Wu Z Q, Zhang B, Yang B L. Research progress on biomass chemical-looping conversion technology[J]. CIESC Journal, 2019, 70(8): 2835-2853.
3	Djandja O S, Wang Z C, Duan P G, et al. Hydrotreatment of pyrolysis oil from waste tire in tetralin for production of high-quality hydrocarbon rich fuel[J]. Fuel, 2021, 285: 119185.
4	毕山松, 郭啸晋, 王波, 等. 重质有机资源热解过程中自由基诱导反应的密度泛函理论研究[J]. 燃料化学学报, 2021, 49(5):684-693.
	Bi S S, Guo X J, Wang B, et al. A DFT simulation on induction reactions involved radicals during pyrolysis of heavy organics[J]. Journal of Fuel Chemistry and Technology, 2021, 49(5): 684-693.
5	石剑, 李术元, 马跃. 爱沙尼亚油页岩及其热解产物的电子顺磁共振研究[J]. 燃料化学学报, 2018, 46(1): 1-7.
	Shi J, Li S Y, Ma Y. Electron paramagnetic resonance study of Estonia oil shale and its pyrolysis products[J]. Journal of Fuel Chemistry and Technology, 2018, 46(1): 1-7.
6	Richter H, Howard J B. Formation of polycyclic aromatic hydrocarbons and their growth to soot—a review of chemical reaction pathways[J]. Progress in Energy and Combustion Science, 2000, 26(4/5/6): 565-608.
7	Liu X C, Cui P, Ling Q, et al. A review on co-pyrolysis of coal and oil shale to produce coke[J]. Frontiers of Chemical Science and Engineering, 2020, 14(4): 504-512.
8	Wang W, Ma Y, Li S Y, et al. Effect of temperature on the EPR properties of oil shale pyrolysates[J]. Energy & Fuels, 2016, 30(2): 830-834.
9	李刚. 煤热解中间体和自由基表征及反应机理研究[D]. 大连: 大连理工大学, 2015.
	Li G. Characterization of coal pyrolysis intermediates and free radicals and research on reaction mechanism[D]. Dalian: Dalian University of Technology, 2015.
10	孔令浩. 类煤结构模型化合物的热解研究[D]. 大连: 大连理工大学, 2015.
	Kong L H. Pyrolysis study of coal-based model compounds[D]. Dalian: Dalian University of Technology, 2015.
11	Wang S Z, Fan X, Zheng A L, et al. Evaluation of atmospheric solids analysis probe mass spectrometry for the analysis of coal-related model compounds[J]. Fuel, 2014, 117: 556-563.
12	成茂, 王胜春, 张德祥. 煤转化过程自由基研究进展[J]. 煤炭转化, 2012, 35(4): 94-98.
	Cheng M, Wang S C, Zhang D X. Research progress on free radicals in coal conversion process[J]. Coal Conversion, 2012, 35(4): 94-98.
13	Morgan T J, Kandiyoti R. Pyrolysis of coals and biomass: analysis of thermal breakdown and its products[J]. Chemical Reviews, 2014, 114(3): 1547-1607.
14	王政, 张兴华, 张逦嘉, 等. 大气颗粒物中环境持久性自由基的电子顺磁共振检测方法[J]. 环境化学, 2020, 39(2): 317-325.
	Wang Z, Zhang X H, Zhang L J, et al. Detection of environmentally persistent free radicals in atmospheric particulate matter by electron paramagnetic resonance[J]. Environmental Chemistry, 2020, 39(2): 317-325.
15	龙盛京, 石建庆, 谢云峰. 流动注射邻菲啰啉化学发光体系测定羟自由基[J]. 分析试验室, 2006, 25(7): 35-38.
	Long S J, Shi J Q, Xie Y F. Detection of hydroxym radicals by flow injection phenanthroline chemiluminescence system[J]. Chinese Journal of Analysis Laboratory, 2006, 25(7): 35-38.
16	王织云, 肖怀秋. 羟基自由基测定技术研究进展[J]. 广西轻工业, 2009, 25(6): 23-24.
	Wang Z Y, Xiao H Q. Research progress of determination technology of hydroxyl radical[J]. Guangxi Journal of Light Industry, 2009, 25(6): 23-24.
17	Lin Y M, Lu G P, Wang R K, et al. Radical route to 1, 4-benzothiazine derivatives from 2-aminobenzenethiols and ketones under transition-metal-free conditions[J]. Organic Letters, 2016, 18(24): 6424-6427.
18	仲晓星, 王德明, 徐永亮, 等. 煤氧化过程中的自由基变化特性[J]. 煤炭学报, 2010, 35(6): 960-963.
	Zhong X X, Wang D M, Xu Y L, et al. The variation characteristics of free radicals in coal oxidation[J]. Journal of China Coal Society, 2010, 35(6): 960-963.
19	韩瑶, 李佳隆, 杨亚磊, 等. 二甲基亚砜捕获-高效液相色谱法测定羟基自由基[J]. 分析科学学报, 2021, 37(2): 177-182.
	Han Y, Li J L, Yang Y L, et al. Determination of hydroxyl radicals by dimethyl sulfoxide trapping-high performance liquid chromatography[J]. Journal of Analytical Science, 2021, 37(2): 177-182.
20	王婕, 张玉龙, 王俊峰, 等. 无机盐类阻化剂和自由基捕获剂对煤自燃的协同抑制作用[J]. 煤炭学报, 2020, 45(12): 4132-4143.
	Wang J, Zhang Y L, Wang J F, et al. Synergistic inhibition effect of inorganic salt inhibitor and free radical scavenger on coal spontaneous combustion[J]. Journal of China Coal Society, 2020, 45(12): 4132-4143.
21	陈军超. TEMPO捕获过氧自由基的机理研究[D]. 哈尔滨: 哈尔滨工业大学, 2018.
	Chen J C. Study on the mechanism of TEMPO capturing peroxy free radicals[D]. Harbin: Harbin Institute of Technology, 2018.
22	Zhou Y, Li L, Jin L J, et al. Pyrolytic behavior of coal-related model compounds connected with C—C bridged linkages by in situ pyrolysis vacuum ultraviolet photoionization mass spectrometry[J]. Fuel, 2019, 241: 533-541.
23	Chen F X, Yan B B, Liu N, et al. Bimetallic oriented catalytic fast pyrolysis of lignin research based on Py-GC/MS[J]. Biomass Conversion and Biorefinery, 2020, 10(4): 1315-1325.
24	Li G S, Dong X M, Fan X, et al. Evaluation of coal-related model compounds using tandem mass spectrometry[J]. Rapid Communications in Mass Spectrometry, 2018, 32(16): 1462-1472.
25	Li W T, Wei X Y, Li X K, et al. Catalytic hydroconversion of lignite-related model compounds over difunctional Ni-Mg₂Si/γ-Al₂O₃[J]. Fuel, 2017, 200: 208-217.
26	Yan J C, Jiao H R, Li Z K, et al. Kinetic analysis and modeling of coal pyrolysis with model-free methods[J]. Fuel, 2019, 241: 382-391.
27	Li L, Fan H J, Hu H Q. A theoretical study on bond dissociation enthalpies of coal based model compounds[J]. Fuel, 2015, 153: 70-77.
28	Li G, Li L, Jin L J, et al. Methyl substitution effect in pyrolysis of coal-based model compound isomers[J]. Fuel Processing Technology, 2018, 178: 371-378.
29	Kong L H, Li G, Jin L J, et al. Pyrolysis behaviors of two coal-related model compounds on a fixed-bed reactor[J]. Fuel Processing Technology, 2015, 129: 113-119.
30	Chen F X, Hou B B, Chen S Y, et al. Biochemicals distribution and the collaborative pyrolysis study from three main components of Helianthus annuus stems based on Py-GC/MS[J]. Renewable Energy, 2017, 114: 960-967.
31	Chen F X, Gong P, Zhang H K, et al. Biomass pyrolysis of Helianthus annuus stems: qualitative and quantitative study based on Py-GC/MS[J]. BioResources, 2016, 11(4): 8589-8614.
32	Wang L L, Pan T Y, Liu P, et al. Hydrogen transfer route during hydrothermal treatment of lignite using the isotope tracer method and improving the pyrolysis tar yield[J]. Energy & Fuels, 2016, 30(6): 4562-4569.
33	He T, Zhang Y M, Zhu Y N, et al. Pyrolysis mechanism study of lignin model compounds by synchrotron vacuum ultraviolet photoionization mass spectrometry[J]. Energy & Fuels, 2016, 30(3): 2204-2208.
34	Jiang G B, Xu L, Cao F L, et al. Electron paramagnetic resonance(EPR)studies on free radical scavenging capacity of EGB and EGB cigarette[J]. Spectroscopy and Spectral Analysis, 2017, 37(4): 1322-1328.
35	Rajib A, Saadeh S, Katawal P, et al. Enhancing biomass value chain by utilizing biochar as a free radical scavenger to delay ultraviolet aging of bituminous composites used in outdoor construction[J]. Resources, Conservation and Recycling, 2021, 168: 105302.

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