O-乙酰基-吡喃木糖热解反应机理的理论研究

黄金保; 刘朝; 童红; 李伟民; 伍丹

O-乙酰基-吡喃木糖热解反应机理的理论研究

1.
贵州民族大学理学院, 贵州贵阳 550025;
2.
重庆大学动力工程学院, 低品位能源利用技术及系统教育部重点实验室, 重庆 400044;
3.
贵州民族大学化学与环境科学学院, 贵州贵阳 550025

基金项目: 国家自然科学基金(51266002);贵州省科学技术基金(黔科合J字[2012]2188号);贵州省"模式识别与智能系统"重点实验室建设项目(黔科合计[2009]4002)。

详细信息

通讯作者:
黄金保(1976- ),E-mail:huangjinbao76@126.com。

中图分类号: TK6;O642
计量
- 文章访问数: 1636
- HTML全文浏览量: 18
- PDF下载量: 515
- 被引次数: 0
出版历程
- 收稿日期: 2012-11-22
- 修回日期: 2013-01-13
- 刊出日期: 2013-03-30

Theoretical studies on pyrolysis mechanism of O-acetyl-xylopyranose

1.
School of Science, Guizhou Minzu University, Guiyang 550025, China;
2.
College of Power Engineering, Chongqing University, Key Laboratory of Low-Grade Energy Utilization Technologies and Systems, Ministry of Education, Chongqing 400044, China;
3.
School of Chemistry and Environmental Science, Guizhou Minzu University, Guiyang 550025, China

摘要

摘要: 为了从微观上理解半纤维素热解过程及其主要产物的形成演变机理,采用密度泛函理论方法B3LYP/6-31G++(d,p),对O-乙酰基-吡喃木糖的热解反应机理进行了量子化学理论研究。在热解过程中,O-乙酰基-吡喃木糖中的O-乙酰基首先脱出,形成乙酸和中间体IM₁,该步反应能垒为269.4 kJ/mol。IM₁进一步发生开环反应形成IM₂,开环反应能垒较低,为181.8 kJ/mol。对中间体IM₂设计了四种可能的热解反应途径,对各种反应的反应物、产物、中间体和过渡态的结构进行了能量梯度全优化,计算了各热解反应途径的热力学和动力学参数。计算结果表明,反应路径(4)和反应路径(2)是O-乙酰基-吡喃木糖热解的主要反应通道,乙酸、乙醛、乙醇醛、丙酮、CO、CO₂、CH₄等小分子产物是热解的主要产物。这与相关实验结果分析是一致的。
- O-乙酰基-吡喃木糖 /
- 热解机理 /
- 密度泛函理论
Abstract: In order to understand the pyrolysis mechanism of hemicellulose and to identify the formation pathways of key products during pyrolysis, the pyrolysis processes of O-acetyl-xylopyranose are investigated by using density functional theory methods at B3LYP/6-31G++(d,p) level. In the pyrolysis, O-acetyl-xylopyranose firstly decomposes to form acetic acid and IM₁ with an energy barrier of 269.4 kJ/mol, and then IM₁ is converted to acyclic carbonyl isomer IM₂ with a low energy barrier of 181.8 kJ/mol. IM₂ further decomposes to form all sorts of small molecules through four possible pyrolytic reaction pathways. The equilibrium geometries of the reactants, transition states, intermediate and products were fully optimized, and the standard thermodynamic and kinetic parameters of every reaction pathway were calculated. The calculation results show that reaction pathways (2) and (4) are the major reaction channels in pyrolysis of O-acetyl-xylopyranose and the major products are low molecular products such as acetic acid, acetaldehyde, glycolaldehyde, acetone, CO, CO₂ and CH₄, which is according with related analysis of experimental results.
- O-acetyl-xylopyranose /
- pyrolysis mechanism /
- density functional theory

HTML全文

参考文献(18)

BRIDGWATER A V, PEACOCKE G V C. Fast pyrolysis processes for biomass[J]. Renew Sust Energ Rev, 2000, 4(1): 1-15.

MCKENDRY P. Energy production from biomass : Part 1 Overview of biomass[J]. Bioresour Technol, 2002, 83(1): 37-46.

MAHINPEV N, MURUGAN P, MANI T, RAINA R. Analysis of bio-oil, biogas, and biochar from pressurized pyrolysis of wheat straw using a tubular reactor[J]. Energy Fuels, 2009, 23(5): 2736-2742.

黄金保, 刘朝, 曾桂生, 谢宇, 童红, 李伟民. 左旋葡聚糖热解机理的密度泛函理论研究[J]. 燃料化学学报, 2012, 40(7): 807-815. (HUANG Jin-bao, LIU Chao, ZENG Gui-sheng, XIE Yu, TONG Hong, LI Wei-min. A density functional theory study on the mechanism of levoglucosan pyrolysis[J]. Journal of Fuel Chemistry and Technology, 2012, 40(7): 807- 815. )

PENG Y, WU S. Fast pyrolysis characteristics of sugarcane bagasse hemicellulose[J]. Cell Chem Technol, 2011, 45(9/10): 605-612.

HOSOYA T, KAWAMOTO H, SAKA S. Pyrolysis behaviors of wood and its constituent polymers at gasification temperature[J]. J Anal Appl Pyrolysis, 2007, 78(2): 328-336.

王树荣, 谭洪, 骆仲泱, 王乐, 岑可法. 木聚糖快速热解试验研究[J]. 浙江大学学报(工学版), 2006, 40(3): 419-423. (WANG Shu-rong, TAN Hong, LUO Zhong-yang, WANG Le, CEN Ke-fa. Experimental research on rapid pyrolysis of xylan[J]. Journal of Zhejiang University (Engineering Science), 2006, 40(3): 419-423.)

YANG H, YAN R, CHEN H, LEE D H, ZHENG C. Characteristics of hemicellulose, cellulose and lignin pyrolysis[J]. Fuel, 2007, 86(12/13): 1781-1788.

RAMIAHM V. Thermogravimetric and differential thermal analysis of cellulose, hemicellulose and lignin[J]. J Polym Sci, 1970, 14(5): 1323-1337.

彭云云, 武书彬. TG-FTIR联用研究半纤维素的热裂解特性[J]. 化工进展, 2009, 28(8): 1478-1484. (PENG Yun-yun,WU Shu-bin. Characteristics and kinetics of sugarcane bagasse hemicellulose pyrolysis by TG- FTIR[J]. Chemical Industry and Engineering Process, 2009, 28(8): 1478-1484.)

BLASI C D, LANZETTA M. Intrinsic kinetics of isothermal xylan degradation in inert atmosphere[J]. J Anal Appl Pyrolysis, 1997, 40-41: 287-303.

LV G, WU S, LOU R. Characteristics of corn stalk hemicellulose in a tubular reactor[J]. Bioresource, 2010, 5(4): 2051-2062.

QU T, GUO W, SHEN L, XIAO J, ZHAO K. Experimental study of biomass pyrolysis based on three major components: Hemicellulose, cellulose, and lignin[J]. Ind Eng Chem Res, 2011, 50(18): 10424-10433.

徐有明. 木材学[M]. 北京: 中国林业出版社, 2006. (XU You-ming. Wood science[M]. Beijing: China Forestry Publishing House, 2006.)

FRISCH M J, TRUCKS G W, SCHLEGEL H B, et al. GAUSSIAN 03. Pittsburgh PA :Gaussian, Inc, 2003.

彭云云, 武书彬. 麦草半纤维素的快速热裂解实验研究[J]. 燃料化学学报, 2011, 39(1): 21-25. (PENG Yun-yun. WU Shu-bin. Fast pyrolysis of hemicellulose in wheat straw[J]. Journal of Fuel Chemistry and Technology, 2011, 39(1): 21-25.)

SHAFIZADEH F, MCGINNIS G D, PHILPT C W. Thermal degradation of xylan and related model compounds[J]. Carbohyd Res, 1972, 25(1): 23-33.

SHEN D K, GU S, BRIDGWATER A V. Study on the pyrolytic behaviour of xylan-based hemicellulose using TG-FTIR and Py-GC-FTIR[J]. J Anal Appl Pyrolysis, 2010, 87(2): 199-206.

施引文献

资源附件(0)

访问统计