1 2 3 4 5

Experiment 2, page 5

2.M.F.Semmelhack, G.R.Clark, J.L.Garcia J.J.Harrison, Y.Thebtaranonth, W.Wulff, and
A.Yamashita, Tetrahedron, 1981, 37, 3957; G.Jaouen, Ann.N.Y.Acad.Sci., 1977, 295,
59; M.F.Semmelhack, ibid., p. 36; D.A. Widdowson, Phil. Trans. Roy. Soc. Lond., 1988, A 326, 595.
3.W.Strohmeier, Chem.Ber., 1961, 94, 2490.
4.This solvent mixture has been determined empirically to give the optimum reaction
temperature and a good backwash of the volatilised chromium hexacarbonyl. See C.A.L.
Mahaffy and P.L.Pauson, Inorg. Syntheses, 1979, 19, 154.
5.A special communal still for the purification of this solvent is set up in the Frankland. It is
essential that you consult a Demonstrator or Simon Bastians BEFOREyou use it.

Appendix

The line is simple to use, but note carefully the following points:-
1.Study the frame before you use it and make sure that you understand its operation. 2.The nitrogen purifying column is chromium(II) adsorbed on silica gel. It must NEVER be
opened to atmosphere. If this occurred it would get dangerously hot.
3.In order to maintain a positive pressure of nitrogen in the system, the pressure should be
adjusted to give a gentle flow through the mercury bubbler.
4.Turn taps slowly and carefully. Make sure that you understand the consequences before
you turn any tap.
5.Always top up the liquid nitrogen trap in the vacuum line before starting to use the frame. It
is essential that you protect the vacuum pump in this way, we cannot afford replacements. 6.Once you have finished using the vacuum line, remember that you must NEVERopen an
active vacuum line to air with the liquid nitrogen trap in place, since this may cause
condensation of liquid oxygen with disastrous (and potentially explosive) consequences.
Always remove the trap immediately prior to venting the system to air.

Steve Marsden, 20/10/98