Laboratory Methods of Inorganic Chemistry, 2nd English Ed. 1928

LEAD TETRAPHENYL. 215

condenser. Heat the mixture on the water-bath until a thick,

grayish mass is formed and no more ethyl iodide condenses and

drips back (20 to 30 minutes). Then remove the condenser and

place in the mouth of the flask a cork which is already fitted with

a gas delivery tube to reach into the lower third of the flask and

with another tube leading to a condenser. Place at the lower

end of the condenser, to serve as a receiving vessel, a 100-cc.

distilling flask with a side-arm condenser (Fig. 7, p. 6). All

the joints should be made air-tight with corks. After filling

the entire apparatus with carbon dioxide, heat the Erlenmeyer

flask to 180 to 220° in an oil-bath, whereupon zinc ethyl distils

over.

Some time after the distillation is finished, disconnect the receiv-

ing vessel and stopper it immediately with a cork, already made

ready, which carries a thermometer and a carbon dioxide de-

livery tube. Keeping a plentiful supply of carbon dioxide flowing

through the apparatus, redistil the liquid. Catch the first run-

nings of zinc ethyl mixed with ethyl iodide in a test-tube filled

with carbon dioxide. At 110° interrupt the distillation, and

replace the test-tube with a thick-walled tube drawn out near its

upper end preparatory to being sealed off. Fill this tube like-

wise with carbon dioxide and distil over all the liquid, heating

the entire distilling flask at the last by fanning it with the flame.

Then seal the tube immediately with the blast lamp. Carefully

avoid any access of air at this or any previous part of the opera-

tion, since this would cause immediate ignition of the zinc ethyl.

Boiling-point, 118°. Yield, about 30 g.

160. Lead Tetraphenyl, Pb(C 6 H 5 ) 4 , by Means of Grignard's
     Reagent; Diphenyl Lead Iodide, Pb(CaH 5 ) 2 I 2.
     The action of metallic magnesium upon etherial solutions of alkyl halides
     results, as was discovered by Grignard, in the formation of compounds in
     which the alkyl radical is bound directly to the magnesium:
     C 6 H 5 Br + Mg = C 6 H 5 MgBr.

The compounds formed are soluble in ether, and themselves contain ether;
their etherial solutions, which constitute the so-called "Grignard'a reagent,"
can be employed for transferring alkyl groups to different metals as well as to
organic radicals of the most varied types.
2 PbCl 2 + 4 C 6 H 5 MgBr - Pb + Pb(C 6 H 6 ) 4 + 2 MgCl 2 + 2 MgBr,.