INDUSTRIAL AND ENGINEERING CHEMISTRY
May, 1931
with water containing lime. On this basis the amount of calcium oxide required per ton of coal containing 4 per cent sulfur is 140 pounds. Experiments Using Flue Gases
Application of the laboratory results was made with a small single-effect rotary scrubber having a capacity of about 100 cubic feet per minute. On account of the small capacity the water used for washing was recirculated from a reservoir. The pump, valves, and connecting piping were constructed of lead and the washer was lead-lined to prevent the attack of the acid. The flow of water was maintained constant a t 8 gallons per minute. Gases were drawn from the breeching of the university power plant after the air preheater. Since they were somewhat diluted by leaks in the blower, they entered the washer a t about 250" F. and having a composition of 5 per cent carbon dioxide, 15 per cent oxygen, 0.1 per cent sulfur dioxide. The effect of the presence of manganese ions on the capacity of the washing water for absorbing sulfur dioxide is shown in Figure 3. The initial concentration of manganese was 0.025 per cent, although it was increased somewhat by evaporation. The efficiency of the washer was determined by finding the sulfur dioxide-carbon dioxide ratio before and after the washer. This expediency was necessary in order to eliminate the effect of air leaks between the points of sampling and also the effect of fluctuations in the sulfur dioxide content of the gases. Although the efficiency of the washer operating
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on flue gases was a great deal lower than that of the laboratory scrubber, it compared favorably with that obtained by other large-scale methods. Furthermore, since the time of contact between the gas and liquid in this washer was of the order of only second, the great increase in efficiency per unit time is apparent. The results further show that with the catalyst the volume of water required is approximately 270 gallons ( l l / d tons) per ton of coal. Further work on the application of these catalysts to the removal of sulfur dioxide from flue gases is in progress. Acknowledgments
The author wishes to express his appreciation to D. B. Keyes, in charge of research in chemical engineering a t the University of Illinois, for his kind suggestions concerning the work. Thanks are also due George A. Lorenz for a part of the laboratory measurements. Literature Cited (1) Johnstone, Paper presented before the Division of Industrial and Englneering Chemistry at the 81st Meeting of the American Chemical Society, Indianapolis, Ind., March 30 to April 3, 1931. (2) Leaver and Thurston, Bur. Mines, Rcpfs. of Investigations 2556 (1923). (3) Report of Advisers to London Power Company, London Ministry of Transport, 3442 and 3714 (1929 and 1930). (4) Ralston. Bur. Mines, Bull. 260 (1927). (5) Reinders and Vles, Rcc. frao. rhim.. 44, 249 (1925). (6) Titoff, 2. p h y s i k . Chem., 45, 641 (1903). (7) Wyld, "Manufacture of Sulfuric Acid," 11, p. 388.
Studies in Liquid Partial Oxidation-II',' R. D. Snow and D. B. Keyes UNIVERSITY OF ILLINOIS, URBANA,ILL.
A catalytic study has been made of the partial oxidaproposed for obtaining the tion of ethyl alcohol, using oxygen as the oxidizing necessary contact between organic l i q u i d s using agent, and in the presence of liquid ethyl alcohol. the gas, liquid, and catalyst air as the oxidizing The work was first done at atmospheric pressure (72"C.) in the laboratory (1, 2'). agent in the presence of a cataand then repeated at approximately 170 pounds per It was thought advisable to lyst is a subject that has resquare inch (100' C.). attempt the liquid-phase parceived very little attention in Certain soluble and insoluble oxidizing catalysts tial oxidation of ethyl alcohol, spite of its importance. It is caused the formation of small amounts of acetaldeusing oxygen as the oxidizing important because the liquid hyde at atmospheric pressure and at 72" C. while ceragent and testing the action of phase, with its high specific tain insoluble oxidizing catalysts caused the formation all the common types of cataheat, permits a better control not only of acetaldehyde but also of acetic acid and carl y s t s . Approximately one of temperature. T e m p e r a bon dioxide at the higher pressure and temperature. hundred fifty catalysts were ture control is an essential tried in this investigation. f a c t o r i n p a r t i a l oxidation. On the other hand, the use of the liquid instead Apparatus and Procedure of the vapor phase presents a t least two new difficulties. One is the question of contact between gas, liquid, and The apparatus used for these semi-quantitative tests was a catalyst; and the other, the development of a catalyst which will operate a t relatively low temperatures. Most of these Schott filter funnel, which consists of an ordinary glass tube organic liquids are volatile and partial oxidations operated funnel with a sintered glass disk. The alcohol, together with under pressure in order to keep the organic compound in a the dissolved or suspended catalyst, was placed above the porous plate and oxygen was forced in a t the bottom through liquid condition are dangerous. The question of contact has already been investigated a t the plate and up through the liquid. The bubbles of oxygen the University of Illinois, and various methods have been formed on the surface of the porous plate were, of course, extremely small. The top of the funnel was closed with a 1 Received March 6. 1931. Presented before the Division of Industrial tinfoil-coated rubber stopper, through which was passed a and Engineering Chemistrq at the 81st Meeting of the American Chemical Hopkins condenser to return as much alcohol as possible from Society, Indianapolis, Ind , March 30 t o April 3, 1931. Published by permission of M. S. Ketchum, Director of the Engineering Experiment the exit gases. Eight funnels were used a t the same time. Station, University of Illinois. Each funnel was surrounded by a steam-heated water bath 2 The details of this work together with other experimental results will which maintained the temperature of the alcohol between 70" he published later in the form of a bulletin of the Engineering Experiment and 75" C. Station.
HE partial oxidation of
T
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Vol. 23, No. 5
Both 95 per cent and anhydrous alcohol were used. At the end of the run the sample was tested for aldehyde by the Schiff's reagent and titrated for acetic acid.
ture-regulating benefit of the liquid phase, it is necessary to use higher pressures. In the case of such mixtures of oxygen and an inflammable compound, however, the danger of serious explosions increases rapidly as the pressure is increased. The Oxidation a t Atmospheric Pressure following experiments were made to study the oxidation of It was found that a t atmospheric pressure, under which alcohol under a moderately increased pressure and temperathese first catalytic studies were made, no acetic acid was ture (100' C.). formed. Except in one instance, the oxidation went only as The catalyst to be tested was dissolved or suspended in the far as aldehyde. Cerium oxide in the presence of alkali alcohol. A 10-cc. sample of the mixture was titrated with produced acetic acid, formic acid, aldehyde resin, and car- 0.1 N sodium hydroxide using phenolphthalein as indicator. bonic acid. The reaction was carried out in either the acid or Another 10-cc. portion of the mixture was placed in a beaker neutral condition in most of the other cases, however. within a modified Parr bomb. The bomb was then closed Group I . Metals in Group I of the periodic system, such as tightly, a lead gasket being used in place of the ordinary copper and copper-zinc couple, gave strong tests for aldehyde. rubber ring. The theoretical amount of oxygen gas required Copper salts, such as copper acetate and copper chloride, also to oxidize the alcohol present to acetic acid was then forced indicated the formation of aldehyde. Potassium, sodium, into the bomb from a similar bomb previously fUed to twice lithium, and gold salts did not show any catalytic activity. the desired pressure. The resulting pressure in the oxidation Group I I . Soluble mercury salts, such as the acetate, bomb was 170 pounds per square inch (11.3 atmospheres) a t showed catalytic activity, but the insoluble salts, such as room temperature. The bomb was then heated for 24 hours mercuric iodide, did not. Soluble salts of zinc and cadmium in a boiling-water bath. The bomb was kept within a heavy also showed activity-for example, the acetates-but not steel shield during the filling and heating. After cooling to insoluble cadmium salts. Calcium and barium salts showed room temperature, the pressure was slowly released by passing no activity. the gases through wash bottles containing water, barium Group III. I n this group the same relation between solu- hydroxide, and neutral sodium sulfite, respectively. The bility and activity appeared. The soluble aluminum salts, bomb was opened and the liquid residue, which usually such as the acetates, showed activity, while the insoluble amounted to 8 cc., was rinsed into a flask and titrated with chloride did not. Perborate, boric acid, and thallium salts 0.1 N sodium hydroxide. Wherever possible, aldehyde was showed no activity. However, boron as a metal in the determined in the liquid residue and in the gases by the neuamorphous state, aluminum, lanthanum, and indium all tral sulfite titration method of Seyewitz and Bardin (3). When showed some activity. the quantity of aldehyde was too small for that determinaGroup I V . Lead and tin salts, especially the soluble ones, tion, a qualitative test was made on the neutralized liquid were particularly active, also the lead and tin metals. Ti- residue with Schiff's reagent. tanium salts and titanium metal acted the same way. On the The results obtained with about forty of the substances other hand, thorium, zirconium, cerium, and germanium previously tested as catalysts were closely parallel to those salts all showed negative results. obtained with the same substances at atmospheric pressure Group V. Vanadium pentoxide and vanadium acetate and 70-75' C . In most cases there was no formation of proved effective. Phosphotungstic acid and phosphomolyb- carbon dioxide or acetic acid. The extent of the oxidation dic acid, as well as phosphorus pentoxide, were active. Po- was the formation of very small concentrations of acetaldetassium arsenate, bismuth acetate, vanadium trichloride, hyde, paraldehyde, and acetal. potassium pyroantimonate, antimony pentoxide, columbium With hopcalite catalysts and with cerous hydroxide SUSchloride were all inactive, as was antimony metal and phos- pended in sodium carbonate solution, however, there was phorus and antimony pentoxide. considerable oxidation of the alcohol to acetaldehyde, acetic Group V I . Chromous acetate, potassium dichromate, acid, and carbon dioxide. The following data are representachrom alum, and selenious acid were all effective, as could be tive of the results obtained with these catalysts: predicted, probably acting more as oxidizing agents than as ACETIC CARBON oxidizing catalysts. Uranium acetate, molybdic acid, tungDIOXIDE ALDEHYDE ACID CATALYST Gram Gram Gram stic acid, sodium tungstate, chromium acetate, and selenium 0.086 Not detd. 0.0684 4-Component hopcalite and tellurium powder were all inactive. 0,0070 Not detd. 0.016 2-Component hopcalite Group VII. Manganese acetate, sulfate, oxide, and metallic Cerous hydroxide in -odilrm _Not _ detd. . carbonate solution Trace 0.0276 manganese were all quite active. Group VZII. The soluble iron, cobalt, and nickel salts, A further study of the mechanism of this oxidation is such as the acetates, were quite active. The insoluble salts, such as the citrate, tannate, etc., were inactive. Palladium, being made. iron, cobalt, and nickel as metals were all quite active. COAcknowledgments balt acetate and nickel acetate in the presence of sulfuric acid seemed to be inactive, also insoluble oxides such as iron oxides. The authors wish to acknowledge the able assistance of The few rare earths tried were inactive. Sherlock Swann, Jr., research associate at the University of Hopcalite, consisting of a combination of oxides of manga- Illinois, and L. H. Rosenfeld, student at the University nese, copper, silver, and cobalt, was quite active. of Illinois. At atmospheric pressure the well-known oxidizing catalysts The authors wish to express their appreciation of the finanin the form of soluble salts were active catalysts in this liquid- cial assistance by the Chemical Foundation, of which Francis phase partial oxidation reaction. The insoluble oxidizing P. Garvan is president and W. W. Buffum, general manager. catalysts, such as hopcalite and others, would operate as catalysts within the liquid phase. It is quite apparent that Literature Cited the mechanism of oxidation in the two cases must be different. (1) Reyes, D. B., University of Illinois Eng. Expt. Sta., C h . 19 (Oct. 16, 1929). Oxidation under Pressure ~
I n order to obtain the advantage of increased thermal activation a t higher temperatures and still retain the tempera-
(2) King, E. P., Swann, Sherlock, Jr., and Keyes, D. P., IND. ENG.CHBY., 91, 1227 (1929). (3) Seyewitz and Bardin, Bull. soc. chim., [3], 8 3 , 1000 (1805).
