Jan., 1940
NOTES
233
tinued until a constant melting point was obtained, generally three to five recrystallizations. Toluene was found to be a better solvent for recrystallization of the monophenyl ether of ethylene glycol than the water-alcohol mixtures. DIVISION OF AGRICULTURAL BIOCHEMISTRY COLLEGE OF AGRICULTURE Molecular weights of the derivatives were deUNIVERSITY OF MINNESOTA NOVEMBER 15,1939 termined by titrating, with standard alkali, a soluST. PAGL,MINNESOTA RECEIVED tion containing 0.5 g. of the ester in 50% alcohol, using phenolphthalein as indicator. The melting The 3-Nitrophthalates of the Mono Ethers points were taken with standard Anschiitz therof Ethylene and Diethylene Glycol mometers in a mechanically stirred bath. B Y A. J. VERAGUTH~ AND HARVEY DIEHL White crystalline derivatives were obtained The problem of identifying the monoethyl ether from the monomethyl, monoethyl, monobutyl and of ethylene glycol (Cellosolve) arose here recently monophenyl ethers of ethylene glycol and from and was successfully solved by the use of the 3- the monomethyl ether of diethylene glycol but nitrophthalic anhydride reagent proposed by not from the monobenzyl ether of ethylene glycol Nicolet and Sachs2 for the identification of alco- or from the monoethyl or monobutyl ethers of dihols. The work has now been extended to the ethylene glycol. other commercially available monoethers of ethylThe 3-nitrophthalates obtained from the monoene glycol (“ Cellosolve” series), and of diethylene ethyl ether of ethylene glycol and from the monoglycol (“Carbitol” series). methyl ether of diethylene glycol crystallize with The ethers were obtained from the Carbide and one molecule of water. Their water of crystalliCarbon Chemicals Corporation, and were purified zation was determined by drying a weighed by fractional distillation. A constant boiling amount of the ester in a vacuum a t 100’ over anfraction was taken, the boiling points and refrac- hydrous magnesium perchlorate (Fischer drying tive indices checking with recorded values. pistol). The percentages of water found were The procedure followed for the preparation of 5.89 and 5.83, the calculated values being 5.98 and the acid 3-nitrophthalate esters of these ether al- 5.43, respectively. cohols was essentially that recommended by TABLE I Nicolet and Sachs. 3-NITROPHTHALATES OF MONOALKYLETHERSOF ETHYLThe anhydride was heated with an excess of the ENE GLYCOL ether alcohol at the boiling point of the latter until -3-NitrophalatesM . P., Mol. w t . all of the anhydride had dissolved and then for Alkyl OC. Calcd. Found fifteen minutes longer. In the cases of those Methyl 128.4-129.0 269 268 * 1 118.0-118.6 283 284 * 3 liquids having boiling points above 150°, toluene Ethyl 94.2-94.5 301 302 * 4 was added to avoid higher temperatures which Ethyl (monohydrate) 121.0-120.6 311 311 * 1 cause decomposition of the esters formed; the Butyl Phenyl 112.0-113.0 331 330 * 2 toluene was then removed by distillation under The 3-nitrophthalate monohydrate of the monoreduced pressure. The oily layer of ester was then extracted with hot water to remove the unreacted methyl ether of diethylene glycol was also a white The anreagents. It was then treated with a hot mixture crystalline solid and melted a t 87-90’. of water and the least amount of ethyl alcohol hydrous 3-nitrophthalate melted a t 91.4-92.2’ necessary to effect complete solution. This solu- and was found to have a molecular weight of 313 tion was allowed to cool slowly with frequent * 1, as compared with the calculated value of 313. scratching to induce crystallization. The initial All attempts to induce the liquid reaction prodcrystallization was generally very slow, periods ucts from the monobenzyl ether of ethylene glycol of standing for several days in a refrigerator some- (“Benzyl Cellosolve”)’ and the monoethyl and times being required. Recrystallization was con- monobutyl ethers of diethylene glycol (“Carbitol” and “Butyl Carbitol, ” respectively) to crys(1) Taken from a Thesis submitted to the Faculty of Purdue University by Mr. Veraguth in partial fulfilment of the requirements tallize failed. for the Degree of Master of Science.
From the author’s experience and the paper by Redemann and Dunn it appears that benzoylaminomalonic ester should find general use in the synthesis of a-amino acids.
(2) Nicolet and Sachs, THISJOURNAL, 47, 2348 (1925); see also the further work of Dickinson, Crosson and Copenhaver, ibid., 69, 1084 (1937).
DEPARTMENT OF CHEMISTRY PURDUEUNIVERSITY LAFAYETTE, INDIANA RECEIVED OCTOBER 9, 1939
