NOTES AND CORRESPONDENCE Function of Water in Catalyzing the Reaction between Nitrogen Tetroxide and Potassium Chloride SIR: I n an experimental study of the reaction between nitrogen tetroxide and nitrogen trichloride it has been shown that the positive NO and negative XC12groups unite, whereas the positive C1 unites with the negative NOS. I n the reaction studied by Whittaker, Lundstrom, and Merz [IND.ENG.CHEM.,23, 1410 (1931)], it is evident that the negative OH of the water unites with the positive XO, and the H ion with the NO3: t
0:
:k
-10:.(j:N::O .. ..
Nitrous acid is amphoteric in the same manner as hypochlorous acid [Noyes and Wilson, J. Am. Chem. SOC.,44, 1630 (1922)]. This is shown by the blue color of nitrous anhydride which appears when an acid is added t o an ice-cold solution of sodium nitrite. The positive NO of the nitrous acid, therefore, unites with the C1 ion of the potassium chloride, forming nitrosyl chloride. Since nitrosyl chloride boils a t -5” C., it escapes, while the OH from the nitrous acid unites with the H ion of the nitric acid, regenerating the water for a new cycle. The NO3 ion takes the place of the C1 ion which has been removed in the nitrosyl chloride. IT.A . NOYES
low-volatile fuels, such as coke, because with hand-firing it is easier to prevent smoking and graphiting with a lowvolatile fuel; incomplete combustion, which cannot easily be avoided with hand-firing, is responsible for this prejudice against highvolatile fuels. When, however, the fuel is burned in pulverized form, with a given ratio of air to coal, and quite automatically, complete combustion is always obtained, and the analysis of the products of combustion can be kept under close control. In a representative 24-hour operation on a boiler fired with pulverized East Kentucky coal, the carbon dioxide content in the products of combustion varied between 14.5 and 16.5 per cent. Illinois coal has also been fired successfully in pulverized form under an HRT. boiler for the production of liquid carbon dioxide; although the carbon dioxide could be maintained a t 15.5 per cent steadily, it was found more satisfactory to run a t 14 per cent carbon dioxide so as to be sure to transform all the sulfur contained in the fuel into sulfur dioxide instead of hydrogen sulfide for protection of the absorbing solution. With each type of fuel there will be a certain percentage of carbon dioxide in the products of combustion which will correspond to the most economical and efficient operation on the entire carbon dioxide production system. Just that percentage of carbon dioxide corresponding to the best condition can be easily maintained when pulverized fuel is used. R. J. BEXDER \T€iITIIG
CORPOR.4TlON
H A R V E YILL. ~ June 16, 1932
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SIR: We do not in any may disagree with the theories mentioned by Bender. Any fuel which will give a high percentage of carbon dioxide and which has a low sulfur and volatile content can be used for making carbon dioxide. Volatile compounds must be completely burned and all sulfur must be oxidized to sulfur dioxide. Up to the present time the size of carbon dioxide plants has of been limited, because of the fact that the consumption in the economical shipping areas has been small, and it has not been pracSIR: I n a recent paper J. H. Pratt gave an interesting summary tical to attempt to adopt pulverized fuels to these small units with their intermittent operations. of the use of liquid carbon dioxide as a refrigerant [Ixn. ENG. The advent of the solid carbon dioxide business is increasing the CHEM.,24, 613 (1932)l. He mentions that “at least 90 per market tremendously, and in the near future pulverized fuels may cent of the liquid carbon dioxide made today is manufactured by the so-called coke process. This consists in burning high-grade be practical in this field. J. H. PRATT coke under specially constructed boilers with carefully regulated LIQCIDC ~ R B O NCORPORATION IC draft, producing flue gases with 17 to 19 per cent carbon dioxide.” C A I C 4 G 0 , ILL. Although common practice up to now has been to burn these July 6, 1932 expensive grades of coke on hand-fired grates for the production of carbon dioxide, evidently better results could be obtained and a In the article on ”Refrigeration in Chemical CORRECTION. more uniform gas analysis maintained if some fuel (particularly ENG.CHEM.,24,602 (1932), the statement was fuel low in ash and in sulfur content) could be burned automati- Industries,” IND. cally in pulverized form. Among these fuels can be listed petro- made that one plant in the United States operated with liquid air leum coke breeze, available a t low cost in territories surrounding as the refrigerant in the separation of helium. The Helium Comoil refineries, and pitch, which can also be found a t a reasonable pany of Louisville, Ky., operates two such plants, one in Kansas cost in many parts of the country. These two fuels, and es- and the other in Colorado, but employs the throttle expansion pecially pitch, have the advantage of a low ash content; for method instead of the engine expansion method used by the petroleum coke it seldom exceeds 2.5 per cent, and for pitch it United States Government. The plant operated by the Government is under the Bureau of Mines and not the Navy, as stated. never reaches 1 per cent. Furthermore, the sulfur content of these fuels is low; for petroleum coke it varies between 0.5 and The Helium Company advises that they have built a helium re1.5 per cent, according to the refining process, and for pitch it is purification plant using liquid air as a refrigerant, produced by the throttle expansion method, and a t the present time they are always below 7 per cent. There does not seem to be any reason why carbon dioxide building under government contract a large helium repurification should be produced only by the combustion of a fuel low in vola- plant of this type a t Sunnyvale, Calif., for the new U. S. Naval Air Station. tile matter; in the past, manufacturers seem to have preferred UNIVERSITY OF ILLISOIS U R B ~ NILL. ~, M a y 27, 1932
Fuel Economy in Production Liquid and Solid Carbon Dioxide
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