From trichlorotris

Eowler, D. E., and E. T. Mcllvaine. 1989. Removal of toxic agents from trichlorotri-flnoroethane cleaning solvents. U.S. Patent 4,842,746, Jnne 27 cited in Chem. Abstr. CA III (IS) 159675T... 

Trifluoromonochloroethylene is obtained from the zinc metal dechlorination of trichlorotri-fluoroethane. The latter is produced by the fluorination of hexachloroethane. 

A suspension of 3.83 g (5.4 mmol) of mer-trichlorotris(dimethylphenyl-phosphine)rhenium(HI) (or its benzene solvate)1 and 2.48 g (65 mmol) of sodium tetrahydroborate(l —) in 100 mL of absolute ethanol is heated under nitrogen on a steam bath until the orange complex dissolves to give a colorless suspension. The solvent is evaporated under reduced pressure, and the residue is extracted with three 75-mL portions of benzene. The benzene extract is evaporated, and the residue is crystallized from 60 mL of absolute ethanol to give prisms of tris(dimethylphenylphosphine)pentahydrido-rhenium(V) the yield is 2.2 g (67%). Anal. Calcd. for C24H38P3Re C, 47.59 H, 6.32 P, 15.34. Found (checkers values) C, 47.60 H, 6.24 P, 15.51. 

Rhenium displays an unusual array of oxidation states and coordination numbers that make it the subject of much current research. The following preparation, adapted from one developed by Chatt and coworkers, provides a convenient synthesis of trichlorooxobis(triphenylphosphine)rhenium(V)1 based on either rhenium(VII) oxide or perrhenate salts. The trichlorooxo compound is a versatile intermediate for the synthesis of other rhenium complexes such as wer-trichlorotris(dimethylphenylphosphine)rhenium-(III),2 as described below. The rhenium(III) complex, in turn, provides a starting point for synthesis of other compounds such as frans-tetrachloro-bis(dimethylphenylphosphine)rhenium(IV)3 and tris(dimethylphenylphos-phinepentahydrido)rhenium(V).4 An alternative synthesis of the trichloro-complex is described in the accompanying preparation by Douglas and Shaw.4... 

The benzene solvate, which by elemental and nmr analyses contains about one benzene per rhenium, may be used for most preparative purposes. Recrystallization from ethanol gives pure orange crystals of mer-trichlorotris-(dimethylphenylphosphine)rhenium(III). Anal. Calcd. for C24H33Cl3P3Re C, 40.77 H, 4.70 Cl, 15.04. Found C, 40.96 H, 4.84 Cl, 15.14. 

The interesting complex chemistry of rhodium has been rather neglected this is probably because most of the synthetic methods for obtaining complexes have been tedious. In general, substitutions of chlorine atoms bonded to rhodium by other ligands are slow, and products have usually been mixtures. The situation is now changing, since novel catalytic approaches to rhodium complexes have been developed. The catalysis in the present synthesis involves the rapid further reaction of the hydrido complex formed from l,2,6-trichlorotri(pyridine)rho-dium(III) in the presence of hypophosphite ion. 

Following extraction of the hydrocarbons with 1,1,2-trichlorotri-fluoroethane, measurements are carried out in the wavelength range from 3.2 to 3.6 pm. 

On the other hand, chlorotrifluoroethylene is derived from reacting trichlorotri-fluoroethane with zinc as shown in Figure 4.50. 

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