1-n-Butyl-3-methylimidazolium chloride (bmimCl) was pre-
pared by N-alkylation of methylimidazole with butyl chloride. 1-
n-Butyl-3-methylimidazolium nitrate (bmimNO3) was prepared
by metathesis in methanol solution from the respective chloride
salts with an equimolar amount of AgNO3.
Dichlorotoluene. Aqueous HCl (37%, 3.4 mmol, 0.28 mL)
was added to toluene (1.4 mmol, 0.15 mL) and P8,8,8,1NO3
(1.4 mmol, 630 mg). The resulting mixture was heated at
80 ◦C. After 24 h HNO3 (69%, 1.4 mmol, 0.09 mL) was added
and the mixture was stirred for an additional 72 h (10%).
1-Chloronaphthalene. Aqueous HCl (37%, 3.4 mmol,
0.28 mL) was added to naphthalene (1.5 mmol, 192 mg) and
P8,8,8,1NO3 (1.5 mmol, 670 mg). The resulting mixture was heated
at 80 ◦C for 90 h (78%).
Chlorination reactions
Note. All the reactions were carried in a flask equipped with
a reflux condenser open to the air. At the end of reactions the
mixtures, after cooling at room temperature, were extracted with
hexane (4 ¥ 2 mL). The % composition of the combined extracts
was determined by GC-MS. For a representative product
(dichloroxylenes, entry 2, Table 3), the yield was confirmed by
isolating and purifying the product via FCC. All structures were
assigned by comparison to authentic samples via GC-MS and
1H NMR.
Dichloronaphthalene. To the previously described reaction
◦
mixture, after 90 h at 80 C, aqueous HNO3 (69%, 1.5 mmol,
0.10 ml) was added, and the reaction mixture was maintained at
the same temperature for an additional 90 h (53%).
Recycling procedure. In the first cycle, aqueous HCl (37%,
1.4 mmol, 0.12 mL) was added to anisole (1.4 mmol, 0.15 mL)
and P8,8,8,1NO3 (1.4 mmol, 630 mg). The resulting mixture was
heated at 80 ◦C for 120 h. After product extraction, traces
of organic solvents and water were eliminated under reduced
pressure. A fresh amount of substrate and HCl (1.4 mmol,
0.12 mL and 1.4 mmol, 0.15 mL, respectively) were then added
to the residual mixture which was then heated again for the next
cycle.
Chloroanisoles. Aqueous HCl (37%, 3.14 mmol, 0.26 mL)
was added to anisole (1.4 mmol, 0.15 mL) and P8,8,8,1NO3
(1.4 mmol, 630 mg). The resulting mixture was heated at 80 ◦C
for 3 h (97%: 75% para and 22% ortho isomers).
Dichloroanisole (Method A). To the previously described
reaction mixture, after 3 h at 80 ◦C was added aqueous
HNO3 (69%, 1.4 mmol, 0.09 ml) and the reaction mixture was
maintained at the same temperature for 60 h (92%: 90% ortho-
para, 2% ortho-ortho isomers and 3% trichloro anisole).
Chloride assay. A 50 mM aqueous solution of AgNO3 was
used to titrate a sample of spent ionic liquid (around 200 mg)
dissolved in methanol (100 mL). 1 mL of a solution of K2Cr2O7
(10% w/v) was used for each sample as indicator.
Dichloroanisole (Method B). Aqueous HCl (37%, 1.4 mmol,
0.12 mL) was added to anisole (1.4 mmol, 0.15 mL) and
of P8,8,8,1NO3 (1.4 mmol, 630 mg). The resulting mixture was
heated at 80 ◦C for 5 days. Then additional aqueous HCl (37%,
1.4 mmol, 0.12 mL) was added. The mixture was allowed to react
at the same temperature for 5 more days (92%: 91% ortho-para
and 1% ortho-ortho isomers).
Acknowledgements
The authors wish to thank Ministero dell’Istruzione Universita`
e Ricerca, and Regione Veneto for funding.
Chloroanisoles (larger scale). Aqueous HCl (37%,
40.5 mmol, 3.35 mL) was added to anisole (18.39 mmol,
2.00 mL) and P8,8,8,1NO3 (18.39 mmol, 8.24 g). The resulting
mixture was heated at 80 ◦C for 3 h. (90%: 2 : 1 para - ortho
ratio). The products were recovered and vacuum distilled to
yield 2.003 g of chloroanisoles (76%).
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The Royal Society of Chemistry 2010
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