Thermal decomposition of carboxylate ionic liquids: trends and mechanisms

被引:216
作者
Clough, Matthew T. [1 ]
Geyer, Karolin [2 ]
Hunt, Patricia A. [1 ]
Mertes, Juergen [2 ]
Welton, Tom [1 ]
机构
[1] Univ London Imperial Coll Sci Technol & Med, Dept Chem, London SW7 2AZ, England
[2] BASF SE, Ludwigshafen, Germany
关键词
INITIO MOLECULAR-DYNAMICS; 1-ETHYL-3-METHYLIMIDAZOLIUM ACETATE; LIGNOCELLULOSIC BIOMASS; CARBON-DIOXIDE; WATER; STABILITY; TEMPERATURES; MIXTURES; PRETREATMENT; DEGRADATION;
D O I
10.1039/c3cp53648c
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The thermal stability of a series of dialkylimidazolium carboxylate ionic liquids has been investigated using a broad range of experimental and computational techniques. Ionic liquids incorporating fluoroalkyl carboxylate anions were found to have profoundly differing thermal stabilities and decomposition mechanisms compared with their non-fluorinated analogues. 1-Ethyl-3-methylimidazolium acetate was observed to largely decompose via an S(N)2 nucleophilic substitution reaction when under inert gas conditions, predominantly at the imidazolium methyl substituent. The Arrhenius equations for thermal decomposition of 1-ethyl-3-methylimidazolium acetate, and the C-2-methylated analogue 1-ethyl-2,3-dimethylimidazolium acetate, were determined from isothermal Thermogravimetric Analysis experiments. The low thermal stability of 1-ethyl-3-methylimidazolium acetate has important implications for biomass experiments employing this ionic liquid. For these two ionic liquids, ion pair and transition state structures were optimised using Density Functional Theory. The activation barriers for the S(N)2 nucleophilic substitution mechanisms are in good agreement with the experimentally determined values.
引用
收藏
页码:20480 / 20495
页数:16
相关论文
共 83 条
[1]   Formation and stability of N-heterocyclic carbenes in water:: The carbon acid pKa of imidazollum cations in aqueous solution [J].
Amyes, TL ;
Diver, ST ;
Richard, JP ;
Rivas, FM ;
Toth, K .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2004, 126 (13) :4366-4374
[2]  
[Anonymous], 2007, CRC HDB CHEM PHYS IN
[3]   Thermal stability and moisture uptake of 1-alkyl-3-methylimidazolium bromide [J].
Arellano, Ian Harvey J. ;
Guarino, Jeiel G. ;
Paredes, Fiona U. ;
Arco, Susan D. .
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 2011, 103 (02) :725-730
[4]  
Armand M, 2009, NAT MATER, V8, P621, DOI [10.1038/NMAT2448, 10.1038/nmat2448]
[5]   Low melting Li/K/Cs acetate salt mixtures as new ionic media for catalytic applications - first physico-chemical characterization [J].
Bajus, Stephanie ;
Deyko, Alexey ;
Boesmann, Andreas ;
Maier, Florian ;
Steinrueck, Hans-Peter ;
Wasserscheid, Peter .
DALTON TRANSACTIONS, 2012, 41 (47) :14433-14438
[6]   Thermal degradation of ionic liquids at elevated temperatures [J].
Baranyai, KJ ;
Deacon, GB ;
MacFarlane, DR ;
Pringle, JM ;
Scott, JL .
AUSTRALIAN JOURNAL OF CHEMISTRY, 2004, 57 (02) :145-147
[7]   Simple and recyclable ionic liquid based system for the selective decomposition of formic acid to hydrogen and carbon dioxide [J].
Berger, M. E. M. ;
Assenbaum, D. ;
Taccardi, N. ;
Spiecker, E. ;
Wasserscheid, P. .
GREEN CHEMISTRY, 2011, 13 (06) :1411-1415
[8]   Structure and Dynamics of 1-Ethyl-3-methylimidazolium Acetate via Molecular Dynamics and Neutron Diffraction [J].
Bowron, D. T. ;
D'Agostino, C. ;
Gladden, L. F. ;
Hardacre, C. ;
Holbrey, J. D. ;
Lagunas, M. C. ;
McGregor, J. ;
Mantle, M. D. ;
Mullan, C. L. ;
Youngs, T. G. A. .
JOURNAL OF PHYSICAL CHEMISTRY B, 2010, 114 (23) :7760-7768
[9]   Deconstruction of lignocellulosic biomass with ionic liquids [J].
Brandt, Agnieszka ;
Grasvik, John ;
Hallett, Jason P. ;
Welton, Tom .
GREEN CHEMISTRY, 2013, 15 (03) :550-583
[10]   Ionic liquid pretreatment of lignocellulosic biomass with ionic liquid-water mixtures [J].
Brandt, Agnieszka ;
Ray, Michael J. ;
To, Trang Q. ;
Leak, David J. ;
Murphy, Richard J. ;
Welton, Tom .
GREEN CHEMISTRY, 2011, 13 (09) :2489-2499