Process for the recovery of antimony pentachloride from a spent antimony catalyst mixture
AssigneeDaikin Kogyo Co., Ltd.
InventorsYonosuke Osaka, Takashi Tohzuka
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Abstract
Antimony pentachloride is recovered from a spent antimony catalyst mixture in a simple manner by bubbling through the spent catalyst mixture an inactive gas such as trichlorotrifluoroethane at an elevated temperature to convert and to remove high melting point or high sublimating point substances as lower boiling point substances; converting fluorinated antimony into chlorinated antimony by means of a chlorinating agent such as carbon tetrachloride; converting antimony (III) into antimony (V) by oxidation with chlorine; and recovering antimony pentachloride by distillation. The antimony pentachloride thus recovered may readily be used as a catalyst for fluorination of a chlorinated hydrocarbon by reaction with hydrogen fluoride.
Claims21
A process for the recovery of antimony pentachloride from a spent liquid catalyst mixture of antimony halides comprising antimony (III) and antimony (V) - halides and halogenated hydrocarbons having high melting points or high sublimation points, said process comprising the steps of:
- a. bubbling an inactive gas through the spent liquid antimony catalyst mixture at a temperature sufficient to convert the high melting point or high sublimation point halogenated hydrocarbons into lower boiling point chlorofluorohydrocarbons and to distill off, with the inactive gas, the lower boiling point chlorofluorohydrocarbons from the spent antimony catalyst mixture to form a first residue, wherein the fluorine content of said antimony halides is at least 0.2 gram-atoms per gram atom of total antimony during step (a);
- then
- b. reacting said first residue with a chlorinating agent to convert antimony fluorides into antimony chlorides, and with chlorine to convert trivalent antimony into pentavalent antimony;
- and
- c. distilling the treated catalyst mixture obtained in step (b) to recover antimony pentachloride as the distillate.
Dependencies are inferred from the claim text.