Using metrics and sustainability considerations to evaluate the use of bio-based and non-renewable Brønsted acidic ionic liquids to catalyse Fischer esterification reactions

Sustainable Chemical Processes

Table 2 Brønsted acidic ionic liquids in esterifications

Ionic liquid cation	Ionic liquid anion	Catalyst loading	T/K	Product	Yield (2–4 hours)	Phase split	Ref.
[b(SO₃H)bim]	[CF₃SO₃]	100%	RT	Octyl hexanoate	82%*	N	[8]
[H-NMP]	[HSO₄]	0.5%	353	Butyl acetate	67%	Y	[13]
[H-NMP]	[MeSO₃]	25%	RT	Butyl acetate	95%	Y	[9]
[H-caprolactam]	[MeSO₃]	20%	303	Butyl acetate	95%	Y	[14]
[H-pyridine]	[HSO₄]	25%	358	Butyl acetate	71%	Y	[15]
[H-NEt₃]	[HSO₄]	25%	363	Octyl acetate	81%	Y	[16]
[H-NEt₃]	[OTs]	18%	363	Octyl acetate	42%	N	[16]
[bmim]	[OTs]	33%	383	Benzyl acetate	100%	Y	[17]