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Vol. 61
unlike that of normal pseudoglobulin. The predominating constituent, about 95%, gives sz0 = 7.4 X cm./sec./dyne and there is present a trace of component with szo = 18 X cm./ sec./dyne. The antitoxic preparation used was 35y0specifically precipitable by diphtheria toxin.
sis since 0.02 molar hydrochloric acid does not change the rate. The velocity of exchange of 0l8 between bicarbonate ion and water has been investigated. It appears that the exchange takes place only through the formation of carbonic acid and carbon dioxide, for the reaction takes place much more LABORATORY OF PHYSICAL CHEMISTRY VTNIVERSITY O F ISCON CONS IN HAROLD P. LUNDGREN slowly under these conditions. In this case the MADISON,WISCONSIK ALWN M. PAPPENHEIMER, JR. ANTITOXINAND VACCINELABORATORY J. W. WILLIAMS rate depends upon the ratio of the carbon diJAMAICA PLAIN, MASSACHUSETTS oxide to the bicarbonate concentrations. The RECEIVED JANUARY 13, 1939 kinetic equation is given by Equation (1) above if ~ ( C O Zis) replaced by 2[3(HC03-) 2(C02)]. OXYGEN EXCHANGE BETWEEN CARBON DIOXIDE, Pure sodium carbonate containing 0.513% of BICARBONATE ION, CARBONATE ION AND WATER 01*has been dissolved in ordinary water. At 25' Sir : the time of half exchange in the case of 0.02 molar solution of sodium carbonate is approximately The rate of oxygen exchange has been used to twenty-eight hours, while no exchange was obstudy the velocity of the reaction between carbon served when the solution was 0.02 molar in sodium dioxide and water when the pH is less than 8. carbonate and 0.04 molar in sodium h y d r ~ x i d e . ~ In this range the predominating reaction of carbon dioxide is with the solvent molecules rather The error in our analyses is perhaps less than one than the hydroxide i0ns.l Assuming that the per cent. of the percentage of 0l8present. These reaction proceeds through the formation of HzC03, results indicate that the reaction proceeds through and the reversal of this reaction, the equation for the formation of the bicarbonate ion. At 30" we find that the exchange between COz the reaction velocity becomes and HzO is substantially complete in about seven - dcy = k(H,O)(COd(a - a) (1) minutes as compared to over an hour at 0'. dt 4(C02) where a is the mole fraction of Ols in carbon Such a rapid exchange might account for the dioxide, and fl is the mole fraction of 0l8in water, decreased 0l8content found in the experiments which because of the large quantity of water by Day and Sheel,5 on the oxidation process remains constant, and k is the specific reaction taking place when heavy oxygen is inhaled by rats. rate constant for the reaction between carbon The exchange should be very much more rapid dioxide and water. The equation is of the first in this case because of the high temperature and order as is usual in these cases2 Moreover, when the possible effect of carbonic anhydrase. The results of these experiments will be reported the water is in excess as, of course, is true in this in greater detail later. case, the rate will be independent of the concen(4) T. Titani, P;.Morita and K. Goto, Bull. Chem. SOC.Japan, 13, tration of the reactant. 329 (1938). Our greater analytical precision probably accounts for In our experiments carbon dioxide containing the difference in results reported here. (5) J. N. E. Day and P. Sheel, Nature, 142, 017 (1938). heavy oxygen was dissolved rapidly in water and UNIVERSITY G. ALEXANDER MILLS then samples of this solution were withdrawn COLUMBIA HAROLD C. UREY NEW YORK,N. Y. from time to time into evacuated vessels in order to RECEIVED JANUARY 23, 1939 separate rapidly the dissolved carbon dioxide from the water. This carbon dioxide was analyzed for its CRYSTALLINE P-METHYLMANNOFURANOSIDE 0l8content with a mass spectrometer. We find AND MANNOSEDIMETHYLACETAL that the velocity constant, k[HaO], of this reS i r : action is equal to 0.0027 a t o", the time being in Application of the furanoside synthesis deseconds, in good agreement with Stadie and O'Briem3 There is no salt effect as shown by veloped in this Laboratory [Pacsu and Green, making the solution 0.045 molar in sodium chlo- THIS JOURNAL, 58, 1823 (1936); Green and ride. Moreover, there is no hydrogen ion cataly- Pacsu, ibid., 59, 1205, 2569 (1937); 60,2056,2288 (1938); Pacsu, ibid., 60, 2277 (1938)l to d-man(1) C.Faurholt, J. Chim. Phys., 21, 400 (1924). ( 2 ) H. A. C. McKay, Natuve, 142, 997 (1938), has shown that nosediethylmercaptal resulted in a 60% yield of athis is generally true for exchange reactions. methylmannofuranoside (m. p. 118-119' ; [ a l Z o D (3) W. C. Stadie and H. O'Brien, J . B i d . Chem., 103, 521 (1933).
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