142 PROCEEDINGS OP THE AMERICAN ACADEMY 



Ethyl h-Monohrompyromucate, (C2H5)C.H2BrOg. — The ethyl ether 

 of the acid can readily be made by heating the acid with absolute 

 alcohol and concentrated sulphuric acid, or by the action of ethyl 

 iodide upon the silver salt * It may conveniently be prej^ared by 

 warming for several hours on the water bath a mixture of four parts 

 of absolute alcohol and three parts of concentrated sulphuric acid 

 with four parts of the acid. A portion of the ether separates while 

 the mixture is still hot, and on cooling and j^i'ecipitatiug with water 

 the quantity of ether obtained is nearly equal to that of the acid 

 taken. The ether, washed with a dilute solution of sodic carbonate, 

 and dried with calcic chloride, had a fragrant odor resembling ethyl 

 pyromucate, and boiled between 234.5° and 236.5°, the greater portion 

 showing a constant boiling-point of 235° t (mercury column completely 

 in vapor) under a pressure of 767 mm. Since it retained a slight 



* We attempted at first to prepare this ether by saturating the alcoholic solu- 

 tion of the acid with hydrocliloric acid gas. The product which we thus ob- 

 tained boiled at 132° under a pressure of 20 mm., and showed no signs of 

 crystallization when strongly cooled. An analysis showed that this product 

 contained mucli too higli a percentage of halogen, and the results agreed quite 

 closely with those required by the formula (C.^jHjjCsH^BrCloOs. 



Calculated for (C,H;5)C5HiBrClo03. Found. 



BrClo 51.71 51.84 52.28 



This behavior of the acid requires further investigation. 



t The thermometer used was a " Zincke " thermometer made by Geissler. 

 It gave the boiling-point of pure naphthaline under a pressure of 709 mm. with 

 the mercury column completely in vapor as 217.0°. According to Crafts (Am. 

 Journal Chemistry, v. 324) this boiling-point is about one degree too low, al- 

 though it agrees exactly with that taken by Geissler in the graduation of his 

 thermometers. Several years ago I gave the boiling-point of a specimen of 

 etliyl pyromucate prepared by Mr. J. J. Thonisen as 195° under a pressure of 

 766 mm. (these Proceedings, vol. xvi. (n. s. viii.) p. 160), this boiling-point 

 being materially lower than that given by Maiaguti (Ann. Cliim. Phys., [2,] 

 Lxiv. 279), 208-210°, under a pressure of 756 mm. Since Canzoneri and 

 Oliveri have recently given the boiling-point of the ether as 205-208°, I 

 have thought it worth while to repeat the determination. Tiie thermometer 

 I had previously used was made by Geissler, but I had neglected to deter- 

 mine its correctness above 200° by means of the boiling-point of naphthaline. 

 An entirely different preparation of the ether, wliich melted at 34-3-5° (some- 

 what higher than the old preparation), showed witli tlie above ' Zincke " ther- 

 mometer tlie constant boiling-point 195° under a pressure of 769 mm., tiie mer- 

 cury column being completcdy in the vapor. The ether was then allowed to 

 stand for eighteen hours with fused calcic chloride, the temperature being for 

 a great part of the time just above the melting-point of the ether. Tiie boiling- 

 point was still found to be constant at 195° under a pressure of 7G8 mm. 



H. B. H. 



