Ionic Liquids: Environment-friendly Greener Solvents for Organic Synthesis

Monica      Dinodia
doi:10.2174/1570179419666220107160725
Abstract

Constituted by ions, ionic liquids (ILs) are evolving as greener solvents for many organic syntheses. Due to their high solvent power and low volatility, ionic liquids are serving as an environment- friendly substitute to conventional volatile organic solvents. The present review introduces ionic liquids as an insight into the diverse recent applications of ILs in organic synthesis.
Keywords: Ionic liquids, environment friendly, organic synthesis, greener solvents, low volatility, high solvent power.
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[1] 
(a) United States environmental protection agency: about green engineering   Available from:  https://www.epa.gov/green-engineering/about-green-engineering(Accessed September 01, 2021).
(b) Anastas, P.T.; Warner, J.C. Green Chemistry: Theory and Practice; Oxford University Press: New York, 1998. 
[2] 
(a) Wasserscheid, P.; Keim, W. Ionic liquids-new “solutions” for transition metal catalysis. Angew. Chem. Int. Ed. Engl., 2000, 39(21),    3772-3789., 
[http://dx.doi.org/10.1002/1521-3773(20001103)39:213772:AIDANIE37723.0.CO;2-5] [PMID:  11091453] 
(b) Wasserscheid, P.; Welton, T. Ionic Liquids in Synthesis, 1st ed; Wiley-VCH, 2002. 
[http://dx.doi.org/10.1002/3527600701] 
(c) Adams, D.J.; Dyson, P.J.; Taverner, S.J. Chemistry in Alternative Reaction Media, 1st ed; Wiley-VCH, 2003. 
[http://dx.doi.org/10.1002/0470869666] 
(d) Singh, R.; Sharma, M.; Mamgain, R.; Rawat, D.S. Ionic liquids: a versatile medium for palladium-catalyzed reactions. J. Braz. Chem. Soc.,  2008, 19, 357-379.
[http://dx.doi.org/10.1590/S0103-50532008000300002] 
(e) Earle, M.J.; Seddon, K.R. Ionic liquids. green solvents for the future. Pure Appl. Chem.,  2000, 72(7), 1391-1398.
[http://dx.doi.org/10.1351/pac200072071391] 
[3] 
Walden, P. Molecular weights and electrical conductivity of several fused salts. Bull. Acad. Imp. Sci. Saint Petersburg,  1914, 1800, 405-422.
[4] 
Hurley, F.H.  Electrodeposition of Ai U.S. Patent 2,446,331 1948.
[5] 
Swain, C.G.; Atsuyoshi, O.; Roe, D.K.; Brown, R.; Maugh, T. Tetrahexylammonium benzoate, a liquid salt at 25.degree., a solvent for ki-netics or electrochemistry. J. Am. Chem. Soc.,  1967, 89(11), 2648-2649.
[http://dx.doi.org/10.1021/ja00987a025] 
[6] 
Boon, J.A.; Levisky, J.A.; Pflug, J.L.; Wilkes, J.S. Frieldel-Crafts reactions in ambient temperature molten-salts. J. Org. Chem.,  1986, 51, 480-483.
[http://dx.doi.org/10.1021/jo00354a013] 
[7] 
Fry, S.E.; Pienta, N.J. Effects of molten-salts on reactions-nucleophilic aromatic-substuitution by halide-ions in molten dodecyltribu-tylphosphonium salts. J. Am. Chem. Soc.,  1985, 107, 6399-6400.
[http://dx.doi.org/10.1021/ja00308a045] 
[8] 
Chauvin, Y.; Gilbert, B.; Guibard, I. Catalytic dimerization of alkenes by nickel-complexes in organochloroaluminate molten-salts. J. Chem. Soc. Chem. Commun.,  1990, 1715-1716.
[http://dx.doi.org/10.1039/c39900001715] 
[9] 
Wilkes, J.S.; Zaworotko, M.J. Air and water stable 1-ethyl-3-methylimidazolium based ionic liquids. J. Chem. Soc. Chem. Commun.,  1992, 965-967.
[http://dx.doi.org/10.1039/c39920000965] 
[10] 
(a) Fuller, J.; Carlin, R.T.; De Long, H.C.; Haworth, D. Structure of 1-ethyl-3-methylimidazolium hexafluorophosphate: model for room temperature molten salts. J. Chem. Soc. Chem. Commun.,  1994, 299-300.
[http://dx.doi.org/10.1039/c39940000299] 
(b) Sandhu, J.S. Recent advances in ionic liquids: green unconventional solvents of this century: Part I. Green Chem. Lett. Rev.,  2011, 4(4), 289-310.
[http://dx.doi.org/10.1080/17518253.2011.572294] 
(c) Aupoix, A.; Pégot, B.; Vo-Thanh, G. Synthesis of imidazolium and pyridinium-based ionic liquids and application of 1-alkyl-3-methylimidazolium salts as pre-catalysts for the benzoin condensation using solvent-free and microwave activation. Tetrahedron,  2010, 66(6), 1352-1356.
[http://dx.doi.org/10.1016/j.tet.2009.11.110] 
(d) Lava, K.; Binnemans, K.; Cardinaels, T. Piperidinium, piperazinium and morpholinium ionic liquid crystals. J. Phys. Chem. B,  2009, 113(28), 9506-9511.
[http://dx.doi.org/10.1021/jp903667e] [PMID:  19586072] 
[11] 
Gao, Y.; Arritt, S.W.; Twamley, B.; Shreeve, J.M. Guanidinium-based ionic liquids. Inorg. Chem.,  2005, 44(6), 1704-1712.
[http://dx.doi.org/10.1021/ic048513k] [PMID:  15762697] 
[12] 
Schwesinger, R.; Link, R.; Wenzl, P.; Kossek, S.; Keller, M. Extremely base-resistant organic phosphazenium cations. Chemistry,  2005, 12(2), 429-437.
[http://dx.doi.org/10.1002/chem.200500837] [PMID:  16189837] 
[13] 
(a) Ding, J.; Armstrong, D.W. Chiral ionic liquids: synthesis and applications.,  Chirality, 2005, 17(5), 281-292.
[http://dx.doi.org/10.1002/chir.20153] [PMID: 15844205] 
(b) MacFarlane, D.R.; Pringle, J.M.; Johansson, K.M.; Forsyth, S.A.; Forsyth, M. Lewis base ionic liquids. Chem. Commun. (Camb.),  2006, (18), 1905-1917.
[http://dx.doi.org/10.1039/b516961p] [PMID: 16767234] 
 (c) Wikipedia, the free encyclopedia: Ionic liquid Available from:
                    https://en.wikipedia.org/wiki/Ionic_liquid(Accessed September 01, 2021)
(d) Vekariya, R.L. A review of ionic liquids: applications towards catalytic organic transformations. J. Mol. Liq.,  2017, 227, 44-60.
[http://dx.doi.org/10.1016/j.molliq.2016.11.123] 
(e) Mallakpour, S.; Dinari, M. Ionic liquids as green solvents: progress and prospects.Green Solvents II; Mohammad, A; Inamuddin, Dr., Ed.; Springer Netherlands: Dordrecht, 2012, pp. 1-32.
[14] 
Bao, W.; Wang, Z.; Li, Y. Synthesis of chiral ionic liquids from natural amino acids. J. Org. Chem.,  2003, 68(2), 591-593.
[http://dx.doi.org/10.1021/jo020503i] [PMID:  12530888] 
[15] 
Chen, X.; Li, X.; Hua, A.; Wang, F. Advances in chiral ionic liquids derived from natural amino acids. Tetrahedron Asymmetry,  2008, 19, 1-14.
[http://dx.doi.org/10.1016/j.tetasy.2007.11.009] 
[16] 
Bica, K.; Gaertner, P. Applications of chiral ionic liquids. Eur. J. Org. Chem.,  2008, 3235-3250.
[http://dx.doi.org/10.1002/ejoc.200701107] 
[17] 
(a) Gadilohar, B.L.; Shankarling, G.S. Choline based ionic liquids and their applications in organic transformation. J. Mol. Liq.,  2017, 227, 234-261.
[http://dx.doi.org/10.1016/j.molliq.2016.11.136] 
(b) Glier, M.B.; Green, T.J.; Devlin, A.M. Methyl nutrients, DNA methylation, and cardiovascular disease. Mol. Nutr. Food Res.,  2014, 58(1), 172-182.
[http://dx.doi.org/10.1002/mnfr.201200636] [PMID:  23661599] 
[18] 
Zeisel, S.H.; da Costa, K-A. Choline: an essential nutrient for public health. Nutr. Rev.,  2009, 67(11), 615-623.
[http://dx.doi.org/10.1111/j.1753-4887.2009.00246.x] [PMID:  19906248] 
[19] 
Steines, S.; Drieben-Holscher, B.; Wasserscheid, P. An ionic liquid as catalyst medium for stereoselective hydrogenations of sorbic acid with ruthenium Complexes. Prakt. J. Chem.,  2000, 342, 348.
[20] 
Owens, G.S.; Abu-Omar, M.M. Methyltrioxorhenium-catalyzed epoxidations in ionic liquids. Chem. Commun. (Camb.),  2000, 1165.
[21] 
Bonhôte, P.; Dias, A-P.; Papageorgiou, N.; Kalyanasundaram, K.; Grätzel, M. Hydrophobic, highly conductive ambient-temperature molten salts. Inorg. Chem.,  1996, 35(5), 1168-1178.
[http://dx.doi.org/10.1021/ic951325x] [PMID:  11666305] 
[22] 
Howarth, J. Oxidation of aromatic aldehydes in the ionic liquid [BMIM] PF6. Tetrahedron Lett.,  2000, 41, 6627-6629.
[http://dx.doi.org/10.1016/S0040-4039(00)01037-6] 
[23] 
Shaabani, A.; Farhangi, E.; Rahmati, A. Ionic liquid promoted selective oxidation of organic compounds with NaBrO3. Monatsh. Chem.,  2008, 139, 905.
[http://dx.doi.org/10.1007/s00706-007-0840-x] 
[24] 
de Souza, R.F.; Dupont, J.; Jeane, E. de L. Dullius Aerobic, catalytic oxidation of alcohols in ionic liquids. J. Braz. Chem. Soc.,  2006, 17(1), 48-52.
[http://dx.doi.org/10.1590/S0103-50532006000100007] 
[25] 
(a) Waffenschmidt, H.; Wasserscheid, P.  onic liquids in regioselective  platinum-catalysed hydroformylation. J. Mol. Catal. Chem.,  2000, 164, 61.
[http://dx.doi.org/10.1016/S1381-1169(00)00259-4] 
(b) Ali, M.; Gual, A.; Ebeling, G.; Dupont, J. Ruthenium;catalyzed hydroformylation of alkenes by using carbon dioxide as the carbon monoxide source in the presence of ionic liquids. ChemCatChem,  2014, 6, 2224.
[http://dx.doi.org/10.1002/cctc.201402226] 
(c) Weiss, A.; Munoz, M.; Haas, A.; Rietzler, F.; Steinruck, H.P.; Haumann, M.; Wasserscheid, P.; Etzold, B.J.M. Boosting the activity in supported ionic liquid-phase-catalyzed hydroformylation via surface functionalization of the carbon support. ACS Catal.,  2016, 6, 2280.
[http://dx.doi.org/10.1021/acscatal.5b02747] 
(d) Walter, S.; Haumann, M.; Wasserscheid, P.; Hahn, H.; Franke, R. n-Butane carbonylation to n-pentanal using a cascade reaction of de-hydrogenation and SILP-catalyzed hydroformylation. AIChE J.,  2015, 61, 893.
[http://dx.doi.org/10.1002/aic.14676] 
[26] 
(a) Mizushima, E.; Hayashi, T.; Tanaka, M. Palladium-catalysed carbonylation of aryl halides in ionic liquid media: high catalyst stability and significant rate-enhancement in alkoxycarbonylation. Green Chem.,  2001, 3, 76.
[http://dx.doi.org/10.1039/b100951f] 
(b) Lin, Q.; Yang, C.; Jiang, W.; Chen, H.; Li, X. Carbonylation of iodobenzene catalyzed by water-souble palladium–phosphine complexes in ionic liquid. J. Mol. Catal. Chem.,  2007, 264, 17-21.
[http://dx.doi.org/10.1016/j.molcata.2006.08.059] 
[27] 
Osichow, A.; Mecking, S. Alkoxycarbonylation of ethylene with cellulose in ionic liquids. Chem. Commun. (Camb.),  2010, 46(27), 4980-4981.
[http://dx.doi.org/10.1039/c0cc00606h] [PMID:  20523927] 
[28] 
García-Suárez, E.J.; Khokarale, S.G.; Buu, Q.N.V.; Fehrmann, R.; Riisager, A. Pd-catalyzed ethylene methoxycarbonylation with Brønsted acid ionic liquids as promoter and phase-separable reaction media. Green Chem.,  2014, 16, 161-166.
[http://dx.doi.org/10.1039/C3GC41380B] 
[29] 
Calo, V.; Nacci, A.; Monopoli, A. Pd–benzothiazol 2ylidene complex in ionic liquids: Efficient catalyst for carbon–carbon coupling reac-tions. J. Organomet. Chem.,  2005, 690, 5458.
[http://dx.doi.org/10.1016/j.jorganchem.2005.07.097] 
[30] 
Caló, V.; Nacci, A.; Monopoli, A.; Laera, S.; Cioffi, N. Pd nanoparticles catalyzed stereospecific synthesis of β-aryl cinnamic esters in ionic liquids. J. Org. Chem.,  2003, 68(7), 2929-2933.
[http://dx.doi.org/10.1021/jo026877t] [PMID:  12662071] 
[31] 
Lachlan, F.M.; Mathews, C.J.; Smith, P.J.; Welton, T. Palladium-catalyzed suzuki cross-coupling reactions in ambient temperature ionic liq-uids:;Evidence for the importance of palladium imidazolylidene complexes. Organometallics,  2003, 22(25), 5350-5357.
[http://dx.doi.org/10.1021/om034075y] 
[32] 
Jaeger, D.A.; Tucker, C.E. Diels-Alder reactions in ethylammonium nitrate, a low-melting fused salt. Tetrahedron Lett.,  1989, 30, 1785.
[http://dx.doi.org/10.1016/S0040-4039(00)99579-0] 
[33] 
(a)  Meracz, I.; Oh, T. Asymmetric Diels–Alder reactions in ionic liquids. Tetrahedron Lett., 2003, 44, 6465., 
[http://dx.doi.org/10.1016/S0040-4039(03)01590-9] 
(b) Zheng, X.; Qian, Y.; Wang, Y. Direct asymmetric aza Diels–Alder reaction catalyzed by chiral 2-pyrrolidinecarboxylic acid ionic liquid. Catal. Commun.,  2010, 11, 567.
[http://dx.doi.org/10.1016/j.catcom.2009.12.021] 
(c) Chiappe, C.; Malvaldi, M.; Pomelli, C.S. The solvent effect on the Diels–Alder reaction in ionic liquids: multiparameter linear solvation energy relationships and theoretical analysis. Green Chem.,  2010, 12, 1330.
[http://dx.doi.org/10.1039/c0gc00074d] 
(d) Shen, Z.L.; Cheong, H.L.; Lai, Y.C.; Loo, W.Y.; Loh, T.P. Application of recyclable ionic liquid-supported imidazolidinonecatalyst in enantioselective Diels–Alder reactions. Green Chem.,  2012, 14, 2626.
[http://dx.doi.org/10.1039/c2gc35966a] 
[34] 
Dal, E.; Lancaster, N.L. Acetyl nitrate nitrations in [bmpy][N(Tf)2] and [bmpy][OTf], and the recycling of ionic liquids. Org. Biomol. Chem.,  2005, 3(4), 682-686.
[http://dx.doi.org/10.1039/b417152g] [PMID:  15703808] 
[35] 
Monopoli, A.; Cotugno, P.; Cortese, M.; Calvano, C.D.; Ciminale, F.; Nacci, A. selective n-alkylation of arylamines with alkyl chloride in ionic liquids: scope and applications. Eur. J. Org. Chem.,  2012, 2012(16), 3105-3111.
[http://dx.doi.org/10.1002/ejoc.201200202] 
[36] 
Earle, M.J.; McCormac, P.B.; Seddon, K.R. Regioselective alkylation in ionic liquids. Chem. Commun. (Camb.),  1998, 2245-2246.
[http://dx.doi.org/10.1039/a806328a] 
[37] 
Hu, Y.; Chen, Z-C.; Le, Z-G.; Zheng, Q-G. Organic reactions in ionic liquids: an efficient method for selective s-alkylation of 2-mercaptobenzothia(xa)zole with alkyl halides. Synth. Commun.,  2004, 34(11), 2039-2046.
[http://dx.doi.org/10.1081/SCC-120037917] 
[38] 
Deligeorgiev, T.; Kaloyanova, S.; Lesev, N.; Vaquero, J.J.; Vaquero, J.J. An easy and fast ultrasonic selective S-alkylation of hetaryl thiols at room temperature. Ultrason. Sonochem.,  2010, 17(5), 783-788.
[http://dx.doi.org/10.1016/j.ultsonch.2010.03.002] [PMID:  20362486] 
[39] 
Yadav, G.D.; Tekale, S.P. selective o-alkylation of 2-naphthol using phosphonium-based ionic liquid as the phase transfer catalyst. Org. Process Res. Dev.,  2010, 14, 722-727.
[http://dx.doi.org/10.1021/op100052g] 
[40] 
Potdar, M.K.; Rasalkar, M.S.; Mohile, S.S.; Salunkhe, M.M. Convenient and efficient protocols for coumarin synthesis via Pechmann con-densation in neutral ionic liquids. J. Mol. Catal. Chem.,  2005, 235(1–2), 249-252.
[http://dx.doi.org/10.1016/j.molcata.2005.04.007] 
[41] 
Tajbakhsh, M.; Alinezhad, H.; Norouzi, M.; Baghery, S.; Akbari, M. Protic pyridinium ionic liquid as a green and highly efficient catalyst for the synthesis of polyhydroquinoline derivatives via Hantzsch condensation in water. J. Mol. Liq.,  2013, 177, 44-48.
[http://dx.doi.org/10.1016/j.molliq.2012.09.017] 
[42] 
Guo, H.; Li, X.; Wang, J-L.; Jin, X.H.; Lin, X-F. Acidic ionic liquid [NMP]H2PO4 as dual solvent-catalyst for synthesis of β-alkoxyketones by the oxa-Michael addition reactions. Tetrahedron,  2010, 66(42), 8300-8303.
[http://dx.doi.org/10.1016/j.tet.2010.08.017] 
[43] 
Keithellakpam, S.; Laitonjam, W.S. A simple, efficient and green procedure for Michael addition catalyzed by [C4dabco]OH ionic liquid. Chin. Chem. Lett.,  2014, 25(5), 767-770.
[http://dx.doi.org/10.1016/j.cclet.2014.01.032] 
[44] 
Yadav, J.S.; Reddy, B.V.S.; Baishya, G. Green protocol for conjugate addition of thiols to alpha,beta-unsaturated ketones using a [bmim]PF6/H2O system. J. Org. Chem.,  2003, 68(18), 7098-7100.
[http://dx.doi.org/10.1021/jo034335l] [PMID:  12946157] 
[45] 
Zicmanis, A.; Katkevica, S.; Mekss, P. Lewis acid-catalyzed Beckmann rearrangement of ketoximes in ionic liquids. Catal. Commun.,  2009, 10(5), 614-619.
[http://dx.doi.org/10.1016/j.catcom.2008.11.008] 
[46] 
Chrobok, A. The baeyer villiger oxidation of ketones with oxone in the presence of ionic liquids as solvents. Tetrahedron,  2010, 66, 6212-6216.
[http://dx.doi.org/10.1016/j.tet.2010.05.091] 
[47] 
Matveeva, E.V.; Odinets, I.L.; Kozlov, V.A.; Shaplov, A.S.; Mastryukova, T.A. Ionic-liquid-promoted Michaelis–Arbuzov rearrangement. Tetrahedron Lett.,  2006, 47(43), 7645-7648.
[http://dx.doi.org/10.1016/j.tetlet.2006.08.050] 
[48] 
Sharifi, A.; Abaee, M.S.; Mirzaei, M.; Salimi, R. Ionic liquid-mediated darzens condensation: An environmentally-friendly procedure for the room-temperature synthesis of α,β-epoxy ketones. J. Indian Chem. Soc.,  2008, 5, 135-139.
[49] 
Duan, Z.; Gu, Y.; Deng, Y. Neutral ionic liquid [BMIm]BF4 promoted highly selective esterification of tertiary alcohols by acetic anhy-dride. J. Mol. Catal. Chem.,  2006, 246, 70-75.
[http://dx.doi.org/10.1016/j.molcata.2005.10.017] 
[50] 
Chinnappan, A.; Kim, H. Environmentally benign catalyst: Synthesis, characterization, and properties of pyridinium dicationic molten salts (ionic liquids) and use of application in esterification. Chem. Eng. J.,  2012, 187, 283-288.
[http://dx.doi.org/10.1016/j.cej.2012.01.101] 
[51] 
Yadav, J.S.; Reddy, B.V.S.; Basak, A.K.; Narsaiah, A.V. [Bmim]BF4 ionic liquid: a novel reaction medium for the synthesis of -amino al-cohols. ChemInform,  2003, 44(5), 1047-1050.
[52] 
Xu, L-W.; Li, L.; Xia, C-G.; Zhao, P-Q. Efficient synthesis of chlorohydrins: ionic liquid promoted ring-opening reaction of epoxides and TMSCl. Tetrahedron Lett.,  2004, 45, 2435-2438.
[http://dx.doi.org/10.1016/j.tetlet.2004.01.042] 
[53] 
Neuhaus, W.C.; Bakanas, I.J.; Lizza, J.R.; Boon, C.T.; Moura, G. Novel biodegradable protonic ionic liquid for the Fischer indole synthesis reaction. Green Chem. Lett. Rev.,  2016, 9(1), 39-43.
[http://dx.doi.org/10.1080/17518253.2016.1149231] 
[54] 
Fan, X.; Li, Y.; Zhang, X.; Qu, G.; Wang, J. An efficient and green preparation of 9-arylacridine-1,8-dione derivatives. Heteroatom Chem.,  2007, 18, 786-790.
[http://dx.doi.org/10.1002/hc.20410] 
[55] 
Le, Z-G.; Xie, Z-B.; Ying, M. Ionic liquid-promoted ring-closure reactions between 1,4-dihydroxyanthraquinone and diamines. Molecules,  2006, 11(6), 464-468.
[http://dx.doi.org/10.3390/11060464] [PMID:  17962779] 
[56] 
Xu, D.Q.; Liu, B.Y.; Xu, Z.Y. Synthesis of 2-Arylimidazo[1, 2-a]pyrimidines in Ionic Liquids. Chin. Chem. Lett.,  2003, 14(10), 1002-1004.
[57] 
De, C.; Lu, B.; Lv, H.; Yu, Y.; Bai, Y.; Cai, Q. One-pot synthesis of dimethyl carbonate from methanol, propylene oxide and carbon diox-ide over supported choline hydroxide/MgO. Catal. Lett.,  2009, 128, 459-464.
[http://dx.doi.org/10.1007/s10562-008-9773-1] 
[58] 
De, C.; Cai, Q.; Wang, X.; Zhao, J.; Lu, B. Highly selective synthesis of propylene glycol ether from methanol and propylene oxide cata-lyzed by basic ionic liquid. J. Chem. Technol. Biotechnol.,  2011, 86, 105-108.
[http://dx.doi.org/10.1002/jctb.2488] 
[59] 
Karmee, S.K.; Hanefeld, U. Ionic liquid catalysed synthesis of -hydroxy ketones. ChemSusChem,  2011, 4(8), 1118-1123.
[http://dx.doi.org/10.1002/cssc.201100083] [PMID:  21717582] 
[60] 
Zhu, A.; Bai, S.; Li, L.; Wang, M.; Wang, J. Choline hydroxide: an efficient and biocompatible basic catalyst for the synthesis of biscouma-rins under mild conditions. Catal. Lett.,  2014, 145, 1089-1093.
[http://dx.doi.org/10.1007/s10562-015-1487-6] 
[61] 
Iglesias, M.; Gonzalez-Olmos, R.; Cota, I.; Medina, F. Brønsted ionic liquids: study of physico-chemical properties and catalytic activity in aldol condensations. Chem. Eng. J.,  2010, 162(2), 802-808.
[http://dx.doi.org/10.1016/j.cej.2010.06.008] 
[62] 
Lobo, H.; Singh, B.; Shankarling, G. Bio-compatible eutectic mixture for multi-component synthesis: a valuable acidic catalyst for synthesis of novel 2,3-dihydroquinazolin-4(1H)-one derivatives. Catal. Commun.,  2012, 27, 179-183.
[http://dx.doi.org/10.1016/j.catcom.2012.07.020] 
[63] 
Wang, P.; Ma, F-P.; Zhang, Z.H. L-(+)-Tartaric acid and choline chloride based deep eutectic solvent: an efficient and reusable medium for synthesis of N-substituted pyrroles via Clauson-Kaas reaction. J. Mol. Liq.,  2014, 198, 259-262.
[http://dx.doi.org/10.1016/j.molliq.2014.07.015] 
[64] 
Bakavoli, M.; Eshghi, H.; Rahimizadeh, M.; Housaindokht, M.R.; Mohammadi, A.; Monhemi, H. Deep eutectic solvent for multi-component reactions: a highly efficient and reusable acidic catalyst for synthesis of 2,4,5-triaryl-1H-imidazoles. Res. Chem. Intermed.,  2015, 41, 3497-3505.
[http://dx.doi.org/10.1007/s11164-013-1467-7] 
[65] 
Gadilohar, B.L.; Kumbhar, H.S.; Shankarling, G.S. Choline peroxydisulfate: environmentally friendly biodegradable oxidizing TSIL for se-lective and rapid oxidation of alcohols. Ind. Eng. Chem. Res.,  2014, 53(49), 19010-19018.
[http://dx.doi.org/10.1021/ie5032919] 
[66] 
Gadilohar, B.L.; Kumbhar, H.S.; Shankarling, G.S. Choline peroxydisulfate oxidizing bio-TSIL: triple role player in the one-pot synthesis of Betti bases and gem-bisamides from aryl alcohols under solvent-free conditions. New J. Chem.,  2015, 39(6), 4647-4657.
[http://dx.doi.org/10.1039/C4NJ02295E] 
[67] 
Gadilohar, B.L.; Pinjari, D.V.; Shankarling, G.S. An energy efficient sonochemical selective oxidation of benzyl alcohols to benzaldehydes by using bio-TSIL choline peroxydisulfate. Ind. Eng. Chem. Res.,  2016, 55(16), 4797-4802.
[http://dx.doi.org/10.1021/acs.iecr.6b00731] 
[68] 
Verma, K.; Sharma, A.; Badru, R. Dicationic ionic liquids as effective catalysts in solvent free strecker synthesis. Curr. Res. Green Sus-taina. Chem,  2021, 4, 100060.
[69] 
Verma, K.; Sharma, A.; Singh, J.; Badru, R. Ionic liquid mediated carbonylation of amines: selective carbamate synthsesis. Sustain. Chem. Pharm.,  2021, 20, 100377.
[70] 
Neumann, J.; Steudte, S.; Cho, C-W.; Thöming, J.; Stolte, S. Biodegradability of 27 pyrrolidinium, morpholinium, piperidinium, imidazoli-um and pyridinium ionic liquid cations under aerobic conditions. Green Chem.,  2014, 16(4), 2174-2184.
[http://dx.doi.org/10.1039/C3GC41997E] 
[71] 
Gonçalves, A.R.P.; Paredes, X.; Cristino, A.F.; Santos, F.J.V.; Queirós, C.S.G.P. Ionic liquids-a review of their toxicity to living organisms. Int. J. Mol. Sci.,  2021, 22(11), 5612.
[http://dx.doi.org/10.3390/ijms22115612] [PMID:  34070636] 
[72] 
Pawowska, B.; Telesiński, A.; Biczak, R. Phytotoxicity of ionic liquids. Chemosphere,  2019, 237, 124436.
[http://dx.doi.org/10.1016/j.chemosphere.2019.124436] [PMID:  31356993] 
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DOI https://dx.doi.org/10.2174/1570179419666220107160725	Print ISSN 1570-1794
Publisher Name Bentham Science Publisher	Online ISSN 1875-6271
Current Organic Synthesis

Ionic Liquids: Environment-friendly Greener Solvents for Organic Synthesis

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