CHLORINAT1ON OF CARBON COMPOUNDS 129 



acetic acid ; whilst dibasic acids with both carboxyl groups 

 attached to the same carbon atom, like malonic acid, 



H 2 C(COOH) 2 , 



on heating break up with separation of carbonic acid. 



If three oxidized carbon atoms are attached to another 

 carbon atom the break up is still easier, and the acid 



HC(COOH) 3 



is only known as the ethyl ester obtained from sodiomalonic 

 and chlorocarbonic esters, which on saponification leads to 

 malonic acid. 



(V) Influence of Chlorine and Nitrogen. 



The loosening of compounds, or more generally, increase 

 in velocity of reaction, caused by oxygen, and perhaps due to 

 its marked negative character and the ionization associated 

 with that, is observed also in the case of nitrogen and 

 chlorine. As appeared previously, chlorine, though in itself 

 more strongly negative than oxygen, is less capable than 

 that element of carrying the negative character into com- 

 pounds; the same is true here, whilst for nitrogen the 

 phenomena are in both respects reversed. 



Dealing only with the effect on the linkage of carbon to 

 carbon, this is weakened by chlorine, as may be seen from 

 Krafft's researches on perchlorination of the saturated 

 hydrocarbons. On repeated heating with iodine chloride 

 all the hydrogen is replaced by chlorine, but at the same 

 time a tendency to break up is observed, so that, e. g. 

 C 3 C1 8 , first produced from propane, decomposes afterwards 

 into C 2 C1 G and CC1 4 , whilst, finally, C 2 C1 6 also yields CC1 4 . 

 From butane the perchlorinated compound C 4 C1 10 could not 

 be obtained, and toluene too, after forming C 6 HC1 4 CC1 3 , 

 breaks up into C 6 C1 6 and CC1 4 . In combination with 

 oxygen the decomposing action of chlorine may be observed 

 in bodies containing the group CC1 3 CO, such as chloral, 



I 



