摘要 |
A process for the purification of tertiary phosphine oxides obtained in a Wittig synthesis as a contaminated by product resulting from the reaction of the corresponding tertiary phosphines, especially triphenylphosphine. The contaminated tertiary phosphine oxides coming from this Wittig synthesis have the formula I <IMAGE> (I) in which R1, R2, and R3 denote C1-C12 alkyl, C5-G8 cycloalkyl, aryl, C7-C20 aralkyl, or C7-C20 alkylaryl. The contaminated phosphine oxide I or phosphine oxide I-containing mixtures, optionally in an inert solvent, are first caused to react with an inorganic or organic acid at temperatures of from 0 DEG to 150 DEG C. to form a crystallized acid salt. The resulting salt crystals are then treated in a purifying step with water or an inorganic base or an organic base to again form the tertiary phosphine oxide. This reformed oxide is then extracted with an inert organic solvent from which the purified tertiary phosphine oxide is finally liberated.
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