

for the Preparation of Tin Tetrethyl. 45 



containing 15 per cent, of tin. When the reaction was finished, 

 the resulting crystalline mass was dissolved in ether and the 

 zinc ethiodide decomposed by the careful addition of alcohol, 

 and eventually acidulated water. Only traces of tin tetrethyl 

 could be detected in the etherial solution, while in the watery 

 solution no tin compounds were present. This result indi- 

 cates that at the heat of the water-bath, zinc ethiodide does 

 not act upon tin. 



Another experiment was therefore tried to see whether, by 

 digesting zinc ethiodide with tin at the temperature at which 

 the former substance decomposes, the formation of tin tetrethyl 

 would take place readily. Fused zinc ethiodide was poured 

 on to about half its own weight of powdered tin, and then 

 digested in an oil-bath for three hours at a temperature of 

 about 160° C. On distilling, the liquid which passed over 

 scarcely even fumed in the air, and was nearly pure tin 

 tetrethyl. 



Although we have not ascertained the exact conditions 

 necessary for obtaining the maximum yield of tin tetrethyl, 

 yet our last experiment would seem to show that these con- 

 ditions would be realized by first obtaining a maximum yield 

 of zinc ethiodide, by acting on a zinc-copper couple with ethyl 

 iodide, then adding powdered tin and digesting at 150°-160°C. 

 until all action is over, and finally distilling. 



The action of ethyl iodide on alloys of zinc containing other 

 metals was tried ; alloys of 10 per cent, of zinc with 20 per 

 cent, of bismuth, aluminium, antimony, and lead respectively 

 were treated with ethyl* iodide, but with negative results. The 

 alloy containing 20 per cent, of bismuth was digested on the 

 water-bath for several hours. After all the ethyl iodide had 

 been converted into zinc ethiodide, further heating was con- 

 sidered unnecesary, as bismuth triethyl decomposes at 50°-60° C. 

 The solid mass was extracted with dry ether when cool, and 

 filtered ; alcohol was first added and then acidulated water, 

 but not even a trace of an organo-metallic bismuth compound 

 could be detected. 



The aluminium alloy also did not yield even a trace of any 

 volatile organic aluminium compound. 



The lead alloy, after the whole of the ethyl iodide was con- 

 verted into the zinc ethiodide, was kept for several hours at a 

 temperature 160°-170° C. ; but on allowing it to cool and 

 extracting with dry ether no lead compound was dissolved. 



The antimony alloy gave traces of a volatile antimony com- 

 pound which distilled with the zinc ethyl, but in such small 

 quantity that the investigation was not carried further. 



It is remarkable that, while alloys of zinc and the above- 



