March, 1924
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
261
TABLE VII-RELATIVE GASIFICATION VALUESOF PETROLEUM OILS
E. t . u. Obtained
-RelativeGasification Value Obtained Calcd. Diff. Km 293 0.696 356 1.00 1.00 0.00 0.0122 283 0.785 352 0,0126 1.15 1.09 0.06 272 0.562 335 0.0120 0.74 0.74 0.00 276 0.556 340 0.0121 0.75 0.77 0.02 283 0.614 348 0.0102b 0.85 0.13 0.72 280 0.414 345 0.0126 0.59 0.03 0.62 278 0.626 0.0122 321 0.78 0.77 0.01 273 0.418 317 0.66 0.0151b 0.13 0.53 296 0.462 368 0.0124 0.71 0.02 0.69 AVERAGE 0.063 0.0124 (I Sample As has been given a value of unity for both the obtained and calculated relative gasification values, because this oil has been chosen as a standard for the comparison of other oils. b Results from very short runs and consequently E70 not thoroughly established.
Sample
per Gallon of Oil 95 450 94:lOO 97,510 96,720 97,130 96,920 99,110 99,110 09,960
GI 0.837 0.820 0.862 0.852 0.857 0.855 0.881 0,881 0.885
T
R
Gz 0.824 0.805 0.812 0,812 0.814 0.812 0.867 0.860 0.826
GZ
GI-RGz 1-R 0.865 0,855 0.925 0,892 0,904 0.885 0.904 0.896 0.939
The B. t. u. obtained per gallon of oil have been included in Table VI1 for comparison. Since these values are dependent upon efficiency and the calorific value of the oil alone, it is evident that they are not a measure of gasification value, which indicates the ease with which an oil can be decomposed into gaseous products. In order to convert the calorific value of the gas produced by the Dayton process into the equivalent of oil gas produced by other processes, the foregoing calorific values should be increased 2.5 times, inasmuch as Dayton gas is approximately 60 Der cent inert.
CONCLUSION It is believed that four factors only-the residue from the fuming sulfuric acid treatment, the average boiling point,
T(1-RR) GI-RGz 339 331 294 309 313 316 308 304 315
E , ~
E70
Obtained 580 665 430 445 418 360 455 382 410
Calcd. 599 653 442 451 510 352 463 316 410
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and the specific gravities of the original oil, and the fuming sulfuric acid residue-are necessary for the calcula6ion of the gasification value of petroleum oils. The four factors are combined into the relation -
The gasification value of that portion of the oil no< attacked by fuming sulfuric acid is eighteen times as great as the part so attacked for those oils usually classed as gas oils. ACKNOWLEDGMENT The writer desires to express his great appreciation t o H. G. Fischer, formerly of the General Oil Gas Corporation, under whose direction this investigation was undertaken and to whose enthusiasm its success is largely due.
Acidity of Vegetable Tan Liquors’ By Erwin J. Kern and J. W. Koenig A. F. GALLUN& SONSCo., MILWAUKEE, WIS.
N vegetabIe tanning it is of importance to know the total titrable acidity of the tan liquors, even though the activity of the liquors is determined by the hydrogen-ion concentration. Apparently, very few tannery laboratories are equipped to make hydrogen-ion measurements, many relying upon the Procter limewater method for determining total acidity. I n an earlier paper2 it was pointed out that solutions of quebracho extract begin to precipitate when the p H value is raised to about 7.2 by the addition of limewater. The proximity of this value to the true neutral point seemed to indicate a fair degree of accuracy for the Procter method, and it was decided to determine the extent to which this would hold true for other common tanning extracts. Tan liquors were prepared as indicated in Table I. In one series of tests the pH value of each liquor was determined by means of the hydrogen electrode and then standard sodium hydroxide solution was added to an aliquot until the pH value was raised to exactly 7.0, giving the total concentration of titrable acidity. This value was also obtained by Procter’s method, in which standard calcium hydroxide solution was added to 10 cc. of filtered tan liquor, with stirring, until a slight, permanent turbidity appeared, which was taken as the end point, the solution then being transferred immediately to the hydrogen electrode and the pH value determined. The comparative results are given in Table I. The results obtained by Procter’s method may be considered very satisfactory for oak bark, wattle bark, and quebracho. It gives no end point whatever for pure solutions of larch bark and gambier extracts. I n the case of the larch, it is interesting to note that an end point is obtained where 0.10 mol
I
1 Presented before the Division of Leather Chemistry at the 66th Meeting of the American Chemical Society, Milwaukee, Wis.. September 10 to 14, 1923. 2 Wilson and Kern, THIS JOURNAL, 14, 1128 (1922).
per liter of lactic acid has been added and that the result is then quite accurate. No end point could be obtained with gambier-a fact appreciated by Procter, who advised the addition of some extract which would give a precipitate with lime and allowing for the acid present in the added extract. The results for the gambier-quebracho mixture show that high results are obtained by this procedure, but that the results become more nearly correct as more acid is added. Procter’s method is admirably suited for routine control work, but should be relied upon only where it has been previously demonstrated that it will check hydrogen-ion measurements. TABLEI GRAMEQUIVALENTS ACID PER LITERFOUNDBY pH Value a t pH Value Titration to LimeEnd Point of pH = 7.0 of Tan water Limewater Liauor with NaOH Method Method Oak bark-18.0 grams solid matter per lilev None 4.16 0.016 0.017 7.02 0.01 3.41 0.025 0.025 7.05 0.10 2.62 0.114 0.114 7.06 Wattle bavk-14.0 gyarns solid matter per liter None 4.16 0.016 0.013 6.95 0.01 3.42 0,020 0.020 7.07 0.10 2.57 0.112 0.109 7.10 Larch bark-18.0 grams solid matter per liter None 4.07 0.018 m 0.01 3.46 0.028 m 0.10 2.67 0.112 0.110 6199 Q u e b r a c h p 1 2 . 0 grams solid matter per liter None 4.48 0.009 0.017 7.42 0.01 3.08 0.018 0.018 7.12 2.43 0.10 0.105 0.111 7.10 Gambier-19.4 g r a m s solid matter per liter m None 4.92 0.004 m 0.014 0.01 3.83 m 2.68 0.102 0.10 Quebvacho-gambier mixture--15.6 grams solid matter per liter None 4.23 0.010 0.032 8.64 0.01 3.48 0,034 0.046 7.45 0.10 2.59 0.124 0.132 7.18
Added Lactic Acid Mols per Liter
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