Substituted Aliphatic Acids. 487 



dry glyceric acid was sealed in a tube with three to four vol- 

 umes of absolute alcohol in the absence of any catalyzing agent 

 and heated for about four hours at a temperature of 180° to 

 190°. The excess of alcohol was then distilled off on a water 

 bath and the ester purified by fractioning under diminished 

 pressure. The product obtained boiled at a constant temper- 

 ature of about 130° at about 20 mm pressure, which corresponds 

 fairly well with the figures given byFrankland and McGregor; 

 — 120° to 121° at 14 mm . The ester boils under atmospheric 

 pressure in the neighborhood of 230°, but at this temperature 

 a certain amount of decomposition takes place which is entirely 

 avoided by the reduction of pressure. 



The alkyloxy esters were obtained by the general method 

 described in the previous paper.* The reactions are : for the 

 alpha ethyloxy propionate, — 



CH 3 CHCl.COOC 2 H 5 + NaOC 2 H 6 



= CH 3 CH.OC 2 H & .COOC 2 H B + NaCl, 



and similarly for the beta product. The alpha ester boils at 

 154-5° to 155-5° and the beta ester at 166°. 



Ethyl lactate and ethyl glycerate are easily soluble, as is to 

 be expected from the fact that they contain hydroxyl groups. 

 The alkyloxy esters appear to be rather difficultly soluble. 



Procedure. 



The experiments were carried out in the thermostat described 

 in the first paperf of this series. The esters were hydrolyzed in 

 250 cm3 flasks which were filled to the mark with decinormal 

 hydrochloric acid and warmed to the temperature of the ther- 

 mostat before starting the reaction. The esters were measured 

 out in quantities of about 2*5 cm3 from a graduated pipette. At 

 regular intervals 25 cm3 portions were withdrawn from the flasks 

 by means of pipettes, run into cold water and titrated immedi- 

 ately with decinormal barium hydroxide solution. Phenol 

 phthalein was used as an indicator. 



Experiments were carried on at temperatures of 25°, 35°, 

 and 45°, duplicate results being obtained in some of the cases. 

 Calculations were made by the use of the well-known titration 

 formula for reactions of the first order. 



The esters studied in this series hydrolyze at such different 

 rates that it is inconvenient to tabulate figures giving the time 

 period represented by each constant. Consequently we record 

 simply the time in minutes over which the reaction was meas- 

 ured. This was in all cases sufficient to allow the hydrolysis 

 to proceed at least two-thirds of the way to completion. Values 

 in parentheses are not counted in the averages, it being assumed 



*This Journal, xxxiv, 293. flbid., xxx, 72. 



