372 DrusJiel and Bancroft — Esters Derived from the 



stitution in the alkyl radical of an ester upon the rate of hjdro- 

 lytic cleavage. 



Preparation of Materials. 



The a-clilor-ethyl acetate was prepared by the method of 

 Simpson,^ by heating eqnimolecular quantities of acetyl chlo- 

 ride and water-free acetaldehyde in a sealed tube at 100°. 

 The ester, boiling at 120°-12-i°, was puriiied by fractionation. 

 As a further criterion of purity it was analyzed for halogen, 

 ^^eighed portions of the ester were hydrolyzed with sodium 

 hydroxide on a steam-bath. The formation of aldehyde resin 

 indicated the presence of acetaldehyde. After filtering ofi and 

 carefully washing the resin, the filtrate was neutralized with 

 nitric acid and the halogen estimated by titrating with decinor- 

 njal silver nitrate, using potassium chromate as an indicator. 



Chlorine found— T. 28-27^, II. 28-62^. 



Chlorine calculated — 28-94^. 



The a-chlor-ethyl propionate was prepared by the method of 

 Eubencamp.f Eqnimolecular portions of water-free acetalde- 

 hyde and propionyl chloride were heated in a sealed tube at 

 120°. The ester, boiling at 134°-136°, was purified by frac- 

 tionation and its halogen content was shown to correspond to 

 theory using the method outlined above for the a-chlor-ethyl 

 acetate. Here, as in the preceding case, aldehyde resin was 

 formed in the hydrolysis. 



The a-ethoxy-ethyl acetate was obtained:}: by heating eqni- 

 molecular portions of the diethyl acetal of acetaldehyde and 

 acetic anhydride in a sealed tube at 150°. The reaction prodnct 

 was washed with a solution of potassium carbonate, then sepa- 

 rated and dried over freshly fused potassium carbonate. That 

 portion distilling over at 125°-130° was collected as the pure 

 ester. The acetal from the above preparation was prepared by 

 the method of Fischer and Giebe.§ 



As a preliminary to the preparation of the /3 substituted 

 esters the following compounds were prepared in considerable 

 quantity : ethylene dibromide, ethylene glycol diacetate, and 

 ethylene glycol. The ethylene dibromide was prepared by the 

 method of Balard.|i The ethylene glycol diacetate was ob- 

 tained by reflnxing a mixture of one mole of ethylene dibromide 

 with two moles of fused anhj'drous potassium acetate in the 

 presence of a mole of glacial acetic acid.*^ A second method"^^ 



* Simpson, Compt. rend., xlvii, 874, 1858, Ann. d. Cliem. n. Pliarm.. cix, 

 156, 1859. 



f Enbencamp, Ann. d. Ohem., ccv, 276, 1884. 



iciaisen, Ber. d. d. Chem. Gesell., xxxi, 1018, 1898. 



§ Fischer and Giebe, ibid., xxx, 3053. 1897. 



II Balard, Ann. d. chim. et d. Phys. (2j, xxxii, 375, 1826. Erlenmeyer and 

 Bunte, Ann. d. Cliem. u. Pharm., clxviii, 64, 1873. 



•T Gattermann, Prac. Methods of Org. Chem. 3d ed., p. 196, 1915. 



** Henry, Ann. d. chim. et d. Phvs. (4), xxvii, 250, 1872. 



