Unit- St ere Theoru of Molecular Volume. 



G05 



defines at B.Pt. 



v - 



v. 



M 



Y M 

 W~ v - VST" 



3-67 

 3-68 

 3-68 

 3-70 





-109-9 

 132-4 

 154-58 

 177-6 



1-570 

 1-576 

 1-577 

 1-585 



2-33 

 233 

 2-33 

 2-33 



Hexvlene, H\> 





Octylene, C y H 1C 



Quite recently (Phil. Mag. xxvii. p. 710, 1914) Le Bas 

 has considered the aliphatic esters, and has shown that 



y 

 the value for ^ for the formic esters, and for the methyl 



and ethyl salts of the fatty acids, decreases until the 

 fourth or fifth members of the series is reached, it then 

 increases. 



The acetic esters behave similarly, but for all higher esters, 



V 



propionic, butyric, &c. the value of ==^ steadily increases 



from the first member onwards. W 



V M 



Remembering that the quantity -tit = v X ^ , if we con. 



M 



sider again the factor ^r r we find that 



c n o . M (X) + ?i.l4 



tor the tormic esters tt? = ^ ,. ^ > 



W lb + u.b 



, ,. ,. M 60+14+71.14 



ror the acetic esters ™ = ., . . • 



W lb+ 6 + n.6 ' 



•and so on for the other esters. So that, as we consider the 

 esters of the higher fatty acids, the second factor gets nearer 

 and nearer to the constant value 2.1 : the specific volumes of 

 all the esters increase as the molecule becomes more complex, 



V 



and hence the value of the ratio ^,- increases. 



\\ 



For methyl propionate the value is :3'715 and for octyl 

 octvrate 4*043 ; all intermediate esters have values which 

 lie between these numbers. 



In the table below the formic and octyric esters are 

 compared. 



