Acidic ionic liquids based on trihexyltetradecylphosphonium chloride-P188.8.131.52 Cl and six different metal chlorides (YCl3, YbCl3, MgCl2, ZnCl2, CuCl2, InCl3) were prepared. The molar fraction of metal chloride (XMClx) used for the formation of acidic ionic liquids with P184.108.40.206 Cl was changed in the range from 0.3 to 0.5. The high catalytic activity in the Diels-Alder reaction of cyclopentadiene and various αβ-unsaturated carbonyl compounds showed ionic liquids at XMClx≤0.4. In general, the highest product yields and endo:exo ratios were achieved in the acidic ionic liquids formed from MgCl2, YCl3 and YbCl3. Thermogravimetric analysis suggested that the prepared ionic liquids were thermally stable up to nearly 400°C. Additionally, they could be reused with only little loss of catalytic activity after the 4th recycle.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.