78 Dnishel and Hill — Ester's of Halogen Substituted Acids. 



Propyl Acetate 

 I ' II 



40° and 40° and 



Propyl Chloracetate 

 I II 



25° and 40° and 



Propyl Bromacetate 



I II 



25° and 40° and 



!3N HCl ■ 



08N HCl 



■05N HCl 



•08N HCl 



•05N HBr ■ 



08NH 



220- 

 239- 

 228- 



201- 

 160- 

 160- 



20-4 

 18-6 

 19-5 

 22-9 



93-0 

 990 

 92.0 



26-9 

 26-9 

 25-3 



134- 

 110- 



229- -Mean 



- 173- 



20-7 -Mean- 95-0 



26-3 -Mean 



.- 122- 



Isobutyl Acetate 

 I II 



25° and 25° and 



•066N HCl -OGGN HCl 



Isobutyl Chloradetate 



I II 



25° and 35° and 



■05N HCl -OoN HCl 



Isobutyl Bromacetate 



I II 



25° and 35° and 



•05N HBr "OSN HBr 



44-3 



44-8 

 42-1 

 45-0 



44-4 



46-7 

 43-5 

 43-8 

 43-4 

 44-5 



22-5 

 20-3 



31-4 

 21-2 

 21-6 



43-5 

 43-5 

 42'6 

 41-6 

 45-1 



25-4 

 22-5 

 26-3 

 24.0 

 26 

 24-0 



43-5 -Mean- 44-3 



21-4 -Mean- 43-3 



Table II. 



41-3 

 40-9 

 40'-3 

 42-4 

 40-7 

 40-7 



24-7 -Mean- 41-2 



Mean values of Table I calculated for 25° and N/20 acid. 



Acetate 



Monocblor- 

 Acetate 



Monobrom- 

 Acetate 



Methvl 

 lO^K 

 33-3 

 35-0 

 33-3* 



20-1 

 21 -St 



26-0 



24-8 



Ethyl 



10»K 



30-3 



32-9 



33-7* 



21-3 

 19-9t 



24-8 

 34-4 



Propyl 



lO^K 



31-0 



34-0 



33-4* 



20-7 

 19-7 



26-3 

 25-0 



Isobutyl 



10»K 



32-8 



33-4 



21-4 

 21-4 



24-7 

 24-7 



Mean of 

 series 

 10= K 

 32-6 



20-8 

 25-0 



* Calculated from deHemptinne's work ; Zeitschr. f. phys. Chem., xiii, 561. 

 f Calculated from Lowenherz's work : Zeitschr. f. phys. Chem., xv, 397. 



Summary. 



1. The esters of monochlor- and monobromacetic acid show 

 no tendency to decompose with liberation of halogen in aque- 

 ous solutions of hydrochloric and hydrobromic acid. Esters of 

 iodine substituted acetic acid in hydriodic acid solution liberate 

 iodine either from the acid set free or fj-om the ester itself. 



2. The rate of hydrolysis depending chiefly on the nature of 

 the acid in the ester, is lowered by introduction of halogen in 

 the acid. The acetic, chloracetic, and bromacetic esters of the 

 same alcohol have constants which are in the ratio 33 : 21 : 25. 

 The esters of the different alcohols and any one acid differ but 

 little in the velocity of this acid hydrolysis reaction.* 



3. The temperature coefficient for 'OSlSr hydrochloric acid 

 used as a catalyzer for the temperature interval of 25° to 35° is 

 2-0 ; for 25° to 40° it is 3-0 ; for •05N' hydrobromic acid it is 

 1-7 for the interval of 25° to 35°. 



* This has been shown also by the work of Julius Meyer and others, see 

 Zeitschr. phys. Chem., Ixvi, 81-125. 



