Bhadury et al.
1385
NMR tube in deuterated solvent at low temperature or by
gas phase injection after drawing the sample through the
septum for MS. The NMR spectra were recorded on a
Bruker Avance DPX 400 spectrometer in acetone-d6 solu-
(7.1 g, 0.024 mol) was added at room temperature. Nitrogen
flow was stopped and the guard tube at this stage was re-
placed by an evacuated and preweighed tedlar bag as de-
scribed above. Zinc powder (3.14 g, 0.048 mol) was then
slowly added to the reaction mixture through a solid addi-
tion tube when almost immediately a violent exothermic re-
action occurred. Gaseous product could be seen evolving
and HFC-227ea was collected in the tedlar bag (2.61 g,
64%).
1
tion using TMS for H NMR and CFCl3 for 19F NMR as in-
ternal references, respectively. Mass spectra were recorded
on a TSQ 7000 mass spectrometer (Finnigan MAT, USA) as
described earlier (8, 9).
Synthesis of HFC-227ea
Acknowledgement
TBAF method
We thank Dr. D.K. Jaiswal, former Associate Director,
DRDE, Gwalior for his keen interest in the work.
Commercial tetrabutylammonium fluoride trihydrate
(TBAF·3H2O) (20 g, 0.063 mol) was transferred into a
round-bottomed flask and heated on a boiling water bath un-
der vacuum (<0.1 mmHg, 1 mmHg = 133.322 4 Pa) for 6 h
when a highly viscous liquid (anhyd. TBAF; about 13 mL)
was obtained; 20 mL of dry DMF was then added to this oil.
The resultant homogenous solution was heated up to 150 °C
in a two-necked 100 mL round-bottomed flask containing a
stirring bar and a dry nitrogen inlet for 45 min. The flask
was connected to a condenser fitted with a CaCl2 guard tube.
The solution was then cooled to 130 °C and hexafluoro-
propene (5 g, 0.033 mol) from a tedlar bag was bubbled into
the flask. At this stage, nitrogen flow was stopped and the
guard tube was replaced by an evacuated and preweighed
tedlar bag by connecting the end of its valve stem to a 3/16
in (1 in = 25.4 mm) i.d. tubing fitted to an adapter. To open
the valve, the tubing was pushed onto the stem to the appro-
priate overlap distance. As soon as HFP was bubbled into
the mixture, a highly exothermic reaction occurred and gas-
eous product (volatile HFC-227ea along with 1-butene) was
collected in the tedlar bag (total 4.5 g) attached to the reac-
tion system. To close the valve of the tedlar bag, the stem
was pulled outward until it stopped. To disconnect the tub-
ing, it was pulled upward or was cut off just above the stem
as described in our earlier work (8, 9). The mixture of vola-
tile products from the tedlar bag was passed into another
round-bottomed flask containing a solution of bromine (3 g
in 6 mL of chloroform) at 0 °C. Butene was completely con-
sumed by bromine and pure gaseous HFC-227ea was col-
lected in another tedlar bag (4.01 g, 70%).
References
1. R.E. Banks. J. Fluorine Chem. 67, 193 (1994).
2. A. McClloch. J. Fluorine Chem. 100, 163 (1999).
3. US Federal Register. 58, 12 May 1993.
4. M. Hudlicky and A.E. Pavlath (Editors). Chemistry of organic
fluorine compounds II: A critical review. ACS, Washington,
D.C. 1995.
5. T. Otsuka and H. Aoyama. US Pat. 6 191 326, 20 February
2001.
6. M.J. Nappa, V.N.M. Rao, and A.C. Sievert. Chem. Abstr. 135,
182 382n (2001).
7. G.A. Olah, J.T. Welch, Y.D. Vankar, M. Nojima, I. Kerekes,
and J.A. Olah. J. Org. Chem. 44, 3872 (1979).
8. P.S. Bhadury, M. Palit, M. Sharma, S.K. Raza, and D.K.
Jaiswal. J. Fluorine Chem. 116, 75 (2002).
9. P.S. Bhadury, S. Singh, M. Sharma, M. Palit, and D.K.
Jaiswal. Can. J. Chem. In press.
10. P.S. Bhadury, B.P. Pant, M. Palit, and D.K. Jaiswal. J. Fluorine
Chem. 85, 115 (1997).
11. P.S. Bhadury. Ph.D. thesis, Jiwaji University, Gwalior, India,
2002.
12. P.S. Bhadury, M. Palit, M. Sharma, S.K. Raza, and D.K.
Jaiswal. J. Fluorine Chem. 113, 47 (2002).
13. S. Singh, P.S. Bhadury, and D.K. Jaiswal. 39th Annual Con-
vention of Chemists, Nagarjunanagar, A.P., India, 22–26 De-
cember 2002.
14. D.J. Burton and D.M. Wiemers. J. Am. Chem. Soc. 107, 5014
(1985).
15. J.A. Wilkinson. Chem. Rev. 92, 505 (1992).
16. O.A. Mascaretti. Aldrichim. Acta, 26, 47 (1993).
17. P. Bosch, F. Camps, E. Chamorro, V. Gasol, and A. Guerrero.
Tetrahedron Lett. 28, 4733 (1987).
Ylide method
Triphenylphosphine (12.6 g, 0.048 mol) was dissolved in
35 mL of dry DMF and placed in a dried three-necked
250 mL round-bottomed flask containing a stirring bar and a
dry nitrogen inlet, at room temperature. The middle neck of
the flask was connected to a condenser fitted with a CaCl2
guard tube. Dibromodifluoromethane (10.08 g, 0.048 mol)
was added in one installment to the well-stirred solution,
when a mildly exothermic reaction occurred. After stirring
the mixture for another 30 min, 2-iodoheptafluoropropane
18. D.P. Cox, J. Terpinski, and W. Lawrynowicz. J. Org. Chem.
49, 3216 (1984).
19. P.S. Bhadury, M. Pandey, and D.K. Jaiswal. J. Fluorine Chem.
73, 185 (1995).
20. P.S. Bhadury, S.K. Raza, and D.K. Jaiswal. J. Fluorine Chem.
99, 115 (1999).
21. J. Cousseau and P. Albert. J. Org. Chem. 54, 5380 (1989).
22. R.K. Sharma and J.L. Fry. J. Org. Chem. 48, 2112 (1983).
© 2004 NRC Canada