Open AccessFriedel-Crafts acylation of 2-methoxynaphthalene with acetic anhydride catalyzed by phosphotungstic acid in ionic liquid
Author(s) -
Yinjuan Guo,
Jing Sun,
Fei Guo,
Yu He,
P. Chen
Publication year - 2019
Publication title -
izvestiâ po himiâ
Language(s) - English
Resource type - Journals
ISSN - 0324-1130
DOI - 10.34049/bcc.51.2.4449
Subject(s) - acetic anhydride , acylation , phosphotungstic acid , chemistry , catalysis , ionic liquid , selectivity , friedel–crafts reaction , yield (engineering) , tetrafluoroborate , acetic acid , nuclear chemistry , organic chemistry , inorganic chemistry , medicinal chemistry , materials science , metallurgy
The Friedel-Crafts acylation of 2-methoxynaphthalene (2-MN) with acetic anhydride (AA) was carried out in the ionic liquid (IL) butylpyridinium tetrafluoroborate ([BPy]BF4) using phosphotungstic acid (H3PW12O40) as the catalyst. The [BPy]BF4-mediated 2-MN acylation displays good conversion and selectivity towards 1-acyl-2-methoxynaphthalene (1-AC-2-MN), with 70.4% conversion of 2-MN and 96.4% selectivity to 1-AC-2-MN obtained under the optimal conditions. Owing to the rearrangement of 1-AC-2-MN, 6-acyl-2-methoxynaphthalene (6-AC-2-MN) can be detected after 1 h of reaction time, with the highest 6-AC-2-MN yield of 11.3% obtained under the examined reaction conditions. The system can be recycled and reused at least 6 times without significant loss of activity, indicating the good stability of the H3PW12O40/[BPy]BF4 catalytic system.