304 SCIENCE PROGRESS. 



I. 2CH 3 -COO-+H 9 = 2CH 3 -COOH + 



II. 2CH 3 -COO- = CH 3 -CH 3 +2C0 2 . 



In equation I. the products of the action are acetic acid 

 and oxygen, in equation II. they are ethane and carbon 

 dioxide, as Kolbe found. 



It is evident that if we wish to favour the second action 

 at the expense of the first, we must so arrange the con- 

 ditions that the ions when they are discharged are as 

 closely packed as possible in order that they may have an 

 opportunity of acting on each other instead of on the water 

 of the solution. This is best effected by having a concen- 

 trated solution and a small anode. In a strong solution 

 there are a great many carriers of the electricity and when 

 these arrive and are discharged at a comparatively small 

 surface, they apparently react together in preference to 

 acting on the water molecules in their neighbourhood. 



Kolbe found that other products besides ethane, oxygen, 

 and carbon dioxide appeared at the anode. The chief of 

 these, indeed the only one whose existence has been con- 

 firmed by other observers, is methyl acetate. Its forma- 

 tion can easily be explained through the equation — 



III. 2CH -COO- = CH.-COO-Crl + CCX, 



Here again two discharged ions react, but now, how- 

 ever, they only lose one molecule of carbon dioxide instead 

 of two as before. This product is never met with in 

 considerable quantities. 



There is still another possibility of reaction between 

 two discharged ions, which, from the nature of the case, is 

 only encountered when we are dealing with acids con- 

 taining a greater number of carbon atoms in the molecule 

 than acetic acid. Thus from the potassium salt of isova- 

 leric acid (CH 3 ) 2 CH'CH 2 'COOK Kolbe obtained not only 

 diisobutyl (CH 3 ) 2 CH-CH 2 -CH 2 -CH(CH 3 ) 2 (eq. II.) but 

 also large quantities of an unsaturated hydrocarbon (CH 3 ) 2 

 CH : CH 2 , the formation of which is expressed by the 

 equation — 



IV. 2 (CH 3 ) 2 CH-CH 2 -COO- = (CH 3 ) 2 CHCH 2 COOH + 



(CH 3 ) 3 CH:CH 2 + C0 2 . 



