A Simple, Effective Boron-Halide Ethoxylation Catalyst
scribed. The catalyst combines the action of a weak
References
nucleophile (halide) and
a
weak electrophile
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[B(OR)3] to activate ethylene oxide and proceeds
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esters B(OR)3 are obtained in a single step from inex-
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chemistry, with water the only by-product. It may be
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halide catalyst also ethoxylates base-sensitive alcohols
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Experimental Section
The boric esters B(OR)3 were prepared by esterification of
B(OH)3 or B2O3 with ROH and concomitant water remov-
al.[15] NaB
NaB
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
Alcohol Ethoxylation – General Considerations
Ethoxylation reactions were performed in a 30-mL stainless
steel reactor using a solution of catalyst (1–4 mol%) in the
neat alcohol ROH (0.01–0.02 mol). The reactor was chilled
with ice, evacuated, and then a premeasured amount (4–
12 equiv.) of EO was condensed into the reactor. The reac-
tor was sealed and brought to reaction temperature, typical-
ly in the range 90–1208C; initial pressures ranged from 7–
10 bar. Reaction times varied, but were usually allowed to
proceed overnight (16 h) whereupon complete EO con-
sumption was achieved (0 bar pressure). The products were
analyzed by a variety of techniques including GC, GC-MS,
HPLC with phenyl isocyanate derivatization, HPLC-MS,
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1
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Acknowledgements
The expert technical assistance of Mr. James H. Haliburton is
appreciated. DuPont Contribution #8927.
Adv. Synth. Catal. 2010, 352, 821 – 826
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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