INDUSTRIAL A N D ENGINEERING CHEMISTRY
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Naphtha NaOCl solution Cc.
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10 50 5 10 50
Vol. 18, No. 8
Table V-Results of Experiments on Specially Prepared Naphtha Solutions -HYPOCHLORITE SOLUTION 4c-HYPOCHLORITE SOLUTION 1-HYPOCHLORITE SOLU~IO 2-N -HYPOCHLORITE SOLUTION 3Treated naphths Treated naphtha Treated naphtha Treated naphtha Doctor NaOCl Doctor NaOCl Doctor NaOCl %S Doctor test NaOCl residue %S test residue %s test residue %S test resldue 0.087 Acidic 0.065 Alkaline 0.073 Alkaline 0.072 Alkaline 0.086 Acidic 0.05 Alkaline 0.07 Alkaline 0.07 Alkaline 0.058 Sliahtlv alkaline 0 . 0 4 Alkaline 0.051 Alkaline 0.06 Alkaline 0.27 Acidic0.225 Alkaline 0.20 Alkaline 0.224 Alkaline Acidic 0.26 0.162 Alkaline 0.19 Alkaline 0.216 Alkaline Alkaline 0.20 0.16 Alkaline 0.17 Alkaline 0.185 Alkaline
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solutions, and produced naphtha solutions sweet to the doctor test without developing acid sodium hypochlorite residues. These results indicate that the type of hypochlorite solution to be used with a petroleum distillate can not be determined in advance of laboratory tests on the distillate in question. If sulfur compounds of the type that produce acids on oxidation are present in very small amounts, it would seem possible to sweeten the distillate satisfactorily with a small volume treatment of a hypochlorite solution of low alkalinity and low chIorine content. On the other hand, if these sulfur compounds are present in larger amounts, the alkalinity, chlorine content, and volume ratio of hypochlorite solution will have to be adjusted accordingly. The naphtha solution of elementary sulfur is very corrosive
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to the copper strip and the copper dish test and is apparently not appreciably affected by treatments with sulfuric acid and sodium hypochlorite solutions; or by filtration through the more common absorbing materials.8 The removal of elementary sulfur from a petroleum distillate may be accomplished by the sodium plumbite treatment as suggested by Wendt and Diggs,ll and by Wood, Lotvy, and Farsgher.2 Acknowledgment
The writers are indebted to W. F. Faragher and Alexander Lowy for their interest in and criticism of this work. Our work with sodium hypochlorite and other petroleum-refining agents was originally outlined by Dr. Faragher. 11
THISJOURNAL, 16, 1113 (1924).
An Improved Laboratory Fractionating Column’ By A. W. T. Loveless RENTCHEMICAL LABORATORY UXIVERSITY OF CHICAGO, CHICAGO, ILL.
I T IS only recently that the knowledge concerning fractional distillation g a i n e d i n industrial practice has b e e n a p p l i e d in the l a b o r a t o r y . It has been known for a number of years that the sharpness of separation of f r a c t i o n s depends principally upon four factors: (1) thermal insulation of the column, (2) ratio of reflux to distillate, (3) intim a c y of contact of vapor and liquid in the column, and (4) length of column. The fractionating columns ordinarily used in laborat o r i e s violate all of these factors with the p o s s i b l e exception of the third. The best column developed to 1 Presented under the title “A Modified Column and Still Head for Accurate Fractional Distillation” before the joint session of the Divisions of Organic Chemistry and Medicinal Products Chemistry at the 71st Meeting of the American Chemical Society, Tulsa, Okla., April 5 to 9, 1926.
date is probably that of Peters and Baker.2 It has been found that with a slight modification this device can be greatly simplified and a high order of precision obtained in the separations. This improved fractionating column resembles an insealed condenser the jacket of which has been silvered and highly evacuated. This method of thermal insulation is quite effective as is known from experience with Dewar flasks. The column is packed with ‘/d-inch lengths of 1/4-inch tubing, as has been suggested by Peters and others. The stillhead may be a simple dephlegmator which controls the reflux ratio or it may be a total reflux condenser to which is sealed a stopcock that diverts a controlled fraction of the condensate. The latter device is much simpler to operate but has been criticized by Peters and Baker. The following results were obtained by distilling a mixture of thionyl chloride and phosphorus oxychloride. This mixture was the result of the action of sulfur dioxide upon phosphorus pentachloride: Column 35 cm. Hempel No. of distillations 7 PCls used, grams 500 SOClz obtained, grams 165 57.8 Yield per cent 76 to 79 Boilidg point range, a C.
50-cm.thermally insulated 2 500 263 92.1 7 6 . 8 to 77.1
Note that there was an increase in yield of nearly 60 per cent and that the product boiled over a range of 0.3’ C. on the second distillation. The distillate gave no test for the presence of phosphorus as phosphoric acid with a molybdic acid reagent. 2
THISJOURNAL, 18, 69 (1926).
Czechoslovak Rayon Industry Depressed-The Czechoslovak rayon industry is undergoing a greater period of depression than any other branch of the textile industry. In recent months the turnover dropped by 25 or 30 per cent from that of last year. Exports are being sent t o South America, where Czechoslovakia has been able to maintain its position.
