Processes for the preparation of octafluoro-[2,2]paracyclophane
AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorsWilliam R. Dolbier, Jr., M. A. Asghar, He-Qi Pan
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Abstract
Processes are disclosed for the preparation of octafluoro-[2,2]paracyclophane which utilize a low temperature, e.g., less than about 200.degree. C., and a reducing agent comprising titanium to promote the dimerization of dihalo-tetrafluoro-p-xylenes. One suitable reducing agent is prepared by combining TiCl.sub.4 with LiAlH.sub.4 in an organic solvent.
Claims17
A process for the preparation of octafluoro-[2,2]paracyclophane, which comprises contacting a dihalo-tetrafluoro-p-xylene with a reducing agent comprising a reduced form of titanium, chloride ions, lithium ions and aluminum ions at a temperature of less than about 200.degree. C. and effective conditions to promote the formation of a reaction product comprising octafluoro-paracyclophane, wherein the yield of octafluoroparacyclophane is at least 20 mole % based on one-half of the moles of dihalo-tetrafluoro-p-xylene contacted with the reducing agent.
A process for the preparation of octafluoro-paracyclophane, which comprises:
- (a) gradually adding a mixture of dibromotetrafluoro-p-xylene and tetrahydrofuran to a reducing agent comprising titanium having a valence of 0 to 3, tetrahydrofuran, lithium ions, aluminum ions and chloride ions, under an inert atmosphere and at a temperature less than about 200.degree. C. to form a reaction product comprising octafluoro-paracyclophane, wherein the yield of octafluoro-paracyclophane is at least 20 mole % based on one-half of the moles of dihalotetrafluoro-p-xylene contacted with the reducing agent;
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- (b) recovering at least a portion of the octafluoro-paracyclophane from the reaction product.
Dependencies are inferred from the claim text.