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THE JOURNAL OF INDUSTRIAL AND ENGINEERING CHEII!IISTRY
Vol. 14, No. 1 2
Alumina as an Absorbent for W a t e r in Organic Combustions’ By H.L. Fisher, H. L. Faust and G . H.Walden COLUMBIA UNIVERSITY, N E W YORK,N. Y ,
N 1912, Johnson2 pubIn this paper the preparation of alumina is described with special muffle furnace to 700” to lished a note on’“Ah750” c. until no more hydroreference to its use in the absorption train for organic combustions, mina as a Drying its adoantages ooer other absorption agents pointed out, and the gen chloridewasgiven Off* A higher temperature should Agent,” in which he ShOwed results of seoeral analyses gioen. not be used since alumina that alumin!, prepared by when prepared at higher heating alumimum hydroxtemperatures no longer abide in a tube a t a “low temperature,” was as efficient as sorbs water.’ The time of heating can be shortened to 30 to 45 min. if a stream of air is blown or drawn through the phosphorus pentoxide for drying purposes. At that time one heating chamber to remove the gaseous products. At the end of us was working on some problems in connection with of the heating the dish was allowed to cool in a desiccator that organic combustions. Since aluminium does not form a stable had no drying agent in it. If the heating is too long or too high carbonate, aluminium oxide and hydroxide ought not to the alumina will no longer cling to the pumice, but will drop ff as a fine powder. It will do this to some extent under any absorb carbon dioxide, and therefore the supposition was oconditions. made that it should be an excellent substitute for anhydrous ALUMINAAS A DRYING AGENT calcium chloride in the absorption train for organic comAccording to Johnson2 the alumina is an excellent drybustions. Our work, which was begun in 1916, has proved that this supposition is correct. In the meantime, two other ing agent up to the time that it has absorbed about 18 per articles have appeared dealing with the efficiency of alu- cent of its weight of water at the ordinary temperature. mina3 in ordinary work as compared with calcium chloride Fifty grams of hydrated aluminium chloride theoretically and other drying agent^.^ After the major portion of our yield about 10.7 g. of aluminium oxide, and this amount work was finished, it was found that alumina had also been ought to absorb about 1.92 g. of water under ideal conditions. used by Wesson5 in the absorption train for combustions, If we consider the average organic substance as containing but only to take up the moisture given off from the moist about 5 per cent of hydrogen, then a 0 . 2 g. sample will soda lime used for absorbing the carbon dioxide in deter- yield approximately 0.09 g. of water, and on this basis the mining the carbon in the nitrosite of rubber. The hydro- aluminium oxide theoretically ought to Buffice for 21 comgen in this case was not wanted and was not determined, bustions. I n practice we have not used the mixture for concentrated sulfuric acid being used simply to remove the more than 4 to 5 combustions. Since alumina is as efficient a drying agent as phosphorus water formed in the combustion. pentoxide, it must be handled accordingly, even though PREPARATION OF THE ALUMINA it gives no outward change in appearance when absorbing FROM ALUMINIUM HYDROXIDE-Ten grams of pure aluminium hydroxide were shaken up with 2 g. of purified and ignited as- moisture. The material was tested out in a practical way for abbestos. The asbestos was added to give greater porosity. The mixture was heated in a 7.5 cm. quartz dish over a nonluminous sorbing the water formed in the combustion of several orflame 5 cm. high, for 1.5 hrs. During the first half-hour the ganic substances. The oxygen for the combustions was material lost 3.101 g., the second, 0.068 g., and the third, 0.014 g. On standing over night in a desiccator containing purified by passing it through a preheater followed by soda concentrated sulfuric acid, it gained 0.018 g. This mixture lime and alumina. Blank determinations were run in each gave excellent results. case and excellent checks obtained before the substance The aluminium hydroxide must be free from alkali. When itself was burned. The carbon dioxide was absorbed by mixed with neutral water it should give only the faintest color with phenolphthalein.6 The mixture can be used over again soda lime and this was followed by a second lot of the alumina simply by heating it once more under the same conditions. in order to insure the complete absorption of the moisture It cannot, however, be reheated very often since the asbestos from the soda lime. Anthracene was chosen for the first soon crumbles to a powder. trials on account of its high carbon content. The theoretical FROMHYDRATEDALUMINIUMCHLORIDE-The alumina as made by the method just outlined tends to pack readily, and then percentage of hydrogen in anthracene is 5.66, and the first it sometimes requires 3 to 4 hrs. for the complete passage of the three results were 5.55, 5.61, and 5.49 per cent. Further carbon dioxide through it. On this account pumice was used results on this and other substances are given below:
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in place of the asbestos and the alumina itself prepared in a different way, as follows: 50 g. of hydrated aluminiumchloride (A1C13.6Hz0) were dissolved in 100 cc. of warm water in a 11.5cm. quartz dish and 50 cc. (about 24 g.) of 12-mesh pumice stirred in. It has to be well stirred with a stout glass rod, especially after most of the water has disappeared, since the mixture foams a good deal and tends to form a cake. The particles of pumice should be kept separated as much as possible. The heating and stirring were continued until there was no danger of later fusion of the hydrated salt and agglomeration of the small lumps of impregnated pumice. This material was then transferred to a 7.5-cm. quartz dish and heated in an electric
Received July 31, 1922. (1912), 911. :Marden and Elliott, THISJOURNAL, 1 (1915), 320; Dover and Marden, J . A m . Chem. SOL.,89 (19171, 1609. 4 Baxter and Warren, J . Am. Chem. SOC.,88 (1911), 340; Baxter and Starkweather, I b i d . , 88 (1916), 2038; A. T . McPherson, I b i d . , 89 (1917), 1317. 6 THISJOURNAL, 6 (1914). 461; 9 (1917), 59. 6 Compare the curve in article by Blum, J . A m . Chem. Soc., 85 (1913), 1
* J . A m . Chem. S O L , 84
1500.
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SUBSTANCE Anthracene
Formula C14HlO
Salicylic acid
CvHeOa
Cane sugar
C~rHg2011
Hydrogen Per cent Calcd. 5 . 6 6 Found 5 . 7 1 5.57 5.63 Calcd. 4 . 3 8 Found 4 . 4 7 4.38 Calcd. 6 . 4 6 Found 6.48 6.46
Carbon Per cent REMARKS 94.34 94.17 Alumina asbestos used 94.36 Alumina pumice 94.12) used 60.84 60 77 Alumina pumice 60:82 used 42.09 42 05 Alumina asbes42:14] tosused
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The advantages of alumina over other absorption agents in organic combustions are as follows: CONCENTRATED SULFURICAcID-The alumina is a solid and therefore it is easier to handle, and it offers much less resistance to the passage of the gases. Furthermore, less weight can be used. 7
Dammer, “Handbuch der anorganischen Chemie,” 8 (1893), 89.
