1158-20-9Relevant academic research and scientific papers
Selective acylation of phenols in boron trifluoride diethyl etherate solution and the mechanistic implication
Xiao, Zhu-Ping,Wei, Wei,Huang, Shen,Lin, Xiao-Yi,Peng, Bin,Wang, Xu-Dong,Zhang, Lei
, p. 8039 - 8042 (2015/02/02)
In the presence of boron trifluoride diethyl etherate (BF3 · OEt2), direct acylation of phenols with free carboxylic acid is chemoselective and regioselective and no demethylation, if any, was observed. The para-directing effect of BF3·OEt2 is attributed to the large steric hindrance of the boron trifluoride-phenolic hydroxyl group complex, which blocks the ortho-acylation from occurrence. Microwave irradiation could not change the regioselectivity of BF3·OEt2 except the reaction time being greatly shortened.
Studies of Collectors. Part 12. The Flotation of Gallium Ion with Polyphenol-type Surfactants
Koide, Yoshifumi,Sakurai, Katsuhiro,Shosenji, Hideto,Yamada, Kimiho
, p. 641 - 645 (2007/10/02)
Polyphenol-type surfactants bearing 1,2-benzenediol or 1,2,3-trihydroxybenzene units were prepared and applied as flotation collectors for Ga(3+).The surfactants exhibited a lowering of surface tension at pH 11 (32-47 dyn cm-1.Gallium(III) was highly floated (80-90percent) at pH 3-8 with equimolar Cn-1H2n-1C(O)C6H3(OH)2 (n=8 or 12) or C7H15C(O)C6H2(OH)3, but not as highly (60percent) with C12H25S4.8(CH2CHCO2H)9.5H.The floatabilities of Ga(3+) in 1 mol dm-3 NaOH were 86-99percent, those in 3 mol dm-3 NaOH were 63-67percent, and those in 5 mol dm-3 NaOH were 26-39percent by using a six-fold molar excess of Cn-1H2n-1C(O)C6H3(OH)2 (n=12 or 18).On the other hand, the floatabilities from 1-5 mol dm-3 NaOH solutions when Cn-1H2n-1C(O)C6H2(OH)3 was added were nearly constant (58-59percent with n=12 and 31-35percent with n=18).The Ga(3+) in a Ga(3+)-Al(3+) mixture was floated selectively at pH3-5 by using C7H15C(O)C6H3(OH)2 or C7H15C(O)C6H2(OH)3.Moreover, the polyphenol-type surfactants in these flotation systems were almost entirely absent (-5 mol dm-3) from 3-5 mol dm-3 NaOH solutions and little decomposed.
