Julie, 1938
NOTES
1507
Procedure.-One hundred grams of the very finely powdered sugar is suspended in two liters of dry acetone to which is added in rapid succession 120 g. of fused zinc chloride (sticks) and a homogeneous mixture of 20 g. of phosphorus pentoxide and 40 g. of phosphoric acid (85%). The whole is shaken mechanically until solution is complete, which lasts about two hours. Then, in COCONUT RESEARCH SCHBME O F CEYLON LUNUWILA, CEYLON RECEIVED JANUARY 4, 1938 order to bring the reaction to completion the solu~ ~ _ _ _ tion is allowed to stand overnight a t room temperature. The mixture is then made alkaline by The Preparation of Diacetone Sugars adding an aqueous suspension of sodium carboBY €1, \:AN GRUNENBERG, C. BREDT A N D WERNER nate, the precipitate of zinc carbonate is filtered, FREUDENBERG washed with acetone, and the combined filtrate The use of concentrated sulfuric acid as catalyst and washings are distilled in vacuo until most of and dehydrant for acetonizations of carbohydrates the acetone is removed. has found general acceptance. Severai disadvanThe resulting aqueous residue is extracted with tages of this method are well known; while high three 150-cc. portions of benzene or ether, which, (4-5y0) concentration of sulfuric acid' brings after removal of the solvent in Z ~ U C Z ~leaves O, the about rapid condensation of acetone, less catalyst diacetone product in practically pure furm leaves considerable quantities of sugar undissolved Acknowledgment is made to the Works Progand favors formation of monoacetone derivatives ress Administration of the City of New York for instead of diacetone sugars. Furthermore, the assistance rendered under Project 465-97-3-120. neutralization of sulfuric acid with anhydrous DEPARTMENT OF CHEMISTRY solid carbonate is time consuming. Other cataFORDHAM UNIVERSITY lysts, zinc chloride,2copper sulfate3 or phosphoric NEWYORK,N. Y. RECEIVED M A Y 6, 1938 a n h ~ d r i d e among ,~ others, have been suggested ; much lower yields however have been obtained as Thermal Data on Organic Compounds. XVIII. compared t o the sulfuric acid method. The Heat Capacity and Entropy of In studying the acetonization of I-sorbose we t-Butyle thylene have obtained by using zinc chloride in combinaBY WM D. KENNEDY,c. HOWARD SHOMATE AND tion with a mixture of ortho- and metaphosphoric GEORGE S. PARKS acids very satisfactory results and have developed The combination of constancy of freezing point the method given below which seems to be generally and constancy of boiling point serves as an excelapplicable to the preparation of diacetone sugars lent criterion of the purity of a chemical comand superior to older methods in yield, speed and pound. This criterion has been used frequently simplicity. The application of this process to the by Kistiakowsky' and hi3 collaborators in their commercial preparation of diacetonesorbose (asextremely accurate determinations of the heats corbic acid synthesis) has been considered. of organic reactions. Recently in the case of tThe following yields of diacetone sugars were butylethyleiie,ib however, they failed to find a obtained : 1-sorbose 85%, d-arabinose 9U%, dconstant freezing point by their aethods, algalactose 'is%, d-mannose 92y0 and d-glucose though otherwise they had every reason to be75770. In all cases the products isolated were lieve in the extreme purity of the material; and practically pure as checked by analysis and roaccordingly they invited us to study the fusion tation. The yields are based on crystallized or distilled products. Due possibly to the acidic behavior of a sample of their material by our caloacetonization medium the same diacetone prod- rimetric method. We have now measured the heat capacities of ucts are obtained which are formed by the use of this olefin between 80 and 298°K. From the sulfuric acid as catalyst. temperature change during the fusion of the crys(1) Bell, J. C k m . soc., 1874 (1935); Ohle, Be*., 71, 562 (1438);
Summary.-The results of standard aiialytical determinations on coconut shells agree well with those recorded by Fleck and colleagues except for the higher value found for cellulose. It is proposed to investigate further the nature of the association of xylan and cellulose in coconut shells.
Reichstein and Griissner, HJw. Chim. A c f o , 17, 311 (1934). ( 2 ) Fisher, B o r . , 60,485 (1927). (3) Ohle and Koller, ibid., 61, 1566 (1924). (4) Smith and Lindberg, ibid., 64, GUS (1931).
(1) (a) Kistiakowsky, Ruhoff,Smith and Vaughan. THIS JOURNAL, 6S. 137, 144 (1936); (a) Doniver, Oresham, K i s t i a k d y and Vaughan. rbrd , 6 9 , 831 (1937). ( c ) Dolliver, Gresham Kistiakowsky, 5 m 1 t h and Vdllghdn, r b t d , 66, 440 (1938).
