Tetrahalophthalic anhydride process
AssigneeEthyl Corporation
InventorsScott A. Bottelberghe, Bonnie G. McKinnie, Steven G. Miller, David E. Raposa
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Abstract
This invention relates to an improvement in a process for preparing tetrabromophthalic anhydride whereby there is a substantial recovery of reactants such as halogen and SO.sub.3 from a vent stream exiting the reaction vessel. The improvement comprises contacting the vent stream with a fluid having a first oleum concentration and recovering a halogen stream and a second stream, having a second oleum concentration wherein the second oleum concentration is greater than the first oleum concentration.
Claims23
In a process for preparing a halogenated phthalic anhydride product in a reaction vessel by reacting phthalic anhydride with halogen in an oleum reaction medium wherein a vent stream from the reaction vessel contains a substantial amount of SO.sub.3, SO.sub.2, and halogen, wherein the halogen is selected from the group consisting essentially of bromine and chlorine, the improvement comprising:
- a) contacting the reaction vessel vent stream with a fluid having a first oleum concentration, and
- b) recovering two liquid streams:
- (i) one containing minor amounts of halogen and having a second oleum concentration;
- and (ii) a second liquid stream comprising halogen and containing a minor amount of SO.sub.3 and SO.sub.2, wherein the second oleum concentration is greater than the first oleum concentration and wherein a substantial amount of the SO.sub.3, SO.sub.2, and halogen in the reaction vessel vent stream has been recovered.
In a process for preparing a brominated phthalic anhydride product in a reaction vessel by reacting phthalic anhydride with bromine in an oleum reaction medium whereby a reaction vessel vent stream containing a substantial amount of SO.sub.3, SO.sub.2, and bromine is present, the improvement comprising:
- a) filtering the brominated phthalic anhydride product from a reaction mass without diluting the reaction mass with water thereby forming a filtrate with a first oleum concentration;
- b) contacting the reaction vessel vent stream with the filtrate having a first oleum concentration;
- and
- c) recovering a first stream containing bromine and a minor amount of SO.sub.3, and a second stream having a second oleum concentration, wherein the second oleum concentration is greater than the first oleum concentration and wherein a substantial amount of the SO.sub.3 and halogen initially present in the reaction vessel vent stream has been recovered.
Dependencies are inferred from the claim text.