Linhart — Hydrolysis of A Iky I Metallic Sulphates. 539 



Art. XLVII. — On the Hydrolysis of Alkyl Metallic Sul- 

 phates ; by G. A. Linhart. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — ccxxxvii.] 

 III. Ethyl Calcium Sulphate and Ethyl Strontium Sulphate. 



It has already been shown* that for methyl-, ethyl-, and 

 propyl barium sulphates the rate of decomposition in acid 

 solution decreases with increase in the weight of the alkyl 

 group. It was the purpose of this investigation to study the 

 effect, on the rate of hydrolysis, of replacing the barium in 

 ethyl barium sulphate by strontium or calcium. 



Preparation and Analysis of the Esters. — The same 

 method was used for the preparation of these esters as that 

 described in the first two papersf of this series. In order, 

 however, to increase the yield the mother liquor from the 

 first crystallization was . concentrated on the steam bath and, 

 before filtering through the hot water funnel, was treated 

 with finely divided carbonate of calcium or strontium in 

 slight excess to neutralize the small amount of alkyl sulphuric 

 acid formed. In the case of the strontium ester the crystals 

 obtained from the fourth fraction were discarded, as tbey con- 

 tained some strontium sulphate, while only the first and sec- 

 ond fractions of the calcium ester were free from calcium 

 sulphate. After treating the crystals as described in the 

 second paper:}: of this series, their composition corresponds to 

 the formulae : 



Sr(C 2 H 6 SOj,.H,0 and Ca(C a H.SO,).2H a O. 



Method of Hydrolysis. — The method of hydrolysis described 

 in previous papers§ was slightly modified. Since these esters 

 gradually lose their water of crystallization, approximately the 

 required amount of the crystallized substance was dissolved in 

 distilled water and the concentration determined in the wet 

 way. Ten cubic centimeters of this solution and 10 om3 of 

 hydrochloric acid were introduced into test-tubes of about 

 40 cm3 capacity, previously constricted at about 1 1/2 inches 

 from the mouth to a size just large enough to allow the stem 

 of a carefully calibrated pipette to go through and the dis- 

 placed air to escape. The tubes were then sealed, allowed to 

 cool, shaken and submerged in the thermostat. The hydro- 

 chloric acid used contained one gram of barium chloride 

 (BaCl 2 .2H 3 0) for every 10 c,n3 to transform the calcium and 

 strontium sulphates, resulting from the hydrolysis of the cal- 



*This Journal, xxxiv, 292. f Ibid., xxxii, 53, and xxxiv, 292. 



% This Journal, xxxiv, 292. § Ibid., xxxii, 53, and xxxiv, 292. 



