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INDUSTRIAL A N D ENGINEERING CHEMISTRY
Vol. 18, N o . 8
POOR GRADE ALCOHOL C,-US.? fihcfure
Behavior of Methanol
The loss of iodine from a solution in commercial methanol is interesting. The initial rate of loss is very high, even as great as 38 per cent in the first 4 weeks. As methanol is considered to be superior to ethyl alcohol as a solvent for iodination, the behavior of the commercial methanol was of considerable interest. It was found, however, that this high initial loss was due to the presence of acetone and unsaturated bodies like allyl alcohol. A solution of iodine in pure methanol lost only 0.7 per cent of its iodine content in the first 2 weeks. Another sample of pure
methanol containing 10 per cent of added acetone lost under similar conditions 50 per cent of its free iodine during the first week. Summary
The purity of alcohol used as a solvent for tincture of iodine plays an important part in the permanence of such solutions. The lower the grade of alcohol, the more rhpid is the loss of free iodine. Addition of potassium iodide inhibits but does not entirely prevent this loss. The impurities of commercial methyl alcohol are mainly responsible for the rapid loss of free iodine dissolved t,herein.
Determination of Water-Soluble Barium in Black Ash' By Walter F. Meister and Thomas Stephens Sr.
LOUISLITHOPONE Co., COLLINSVILLE, ILL.
ARIUM black ash is not a common article of commerce, but it is by no means a rarity and its manu-
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facture and sale are increasing yearly. The literature on the subject is rather barren and practically no textbooks give a method for this analysis. A method worked out by the writers and checked by others dealing with the same product is therefore described. Method
Weigh exactly 200 mg. of ash, and brush carefully into a 250-cc. assay beaker flask. The flask should contain about 25 cc. of distilled water to prevent loss by dusting. Add about 100 cc. of hot distilled water to flask, cover with watch glass, place on hot plate, and boil contents for 5 minutes. Remove from heat and filter a t once into a 500-cc. Erlenmeyer suction flask fitted with a Walter's crucible holder and a No. 3 Gooch crucible having an asbestos filter mat about 5 mm. thick. The filtered solution must be perfectly clear; filtration of sample should be complete in 1 minute. Wash the assay flask with about 100 cc. of boiling water, filtering through the Gooch. Pour the contents of the Erlenmeyer flask into a beaker, wash the flask three times. To the beaker add 25 cc. 0 . 5 N sulfuric acid, place on a hot plate, boil 5 minutes, allow to settle 1 hour; filter through Munktells' No. OB 11 cm. paper, wash, ignite, and weigh. 1
Received April 8, 1926.
Weight of ignited precipitate X 0.7258 X 500 = per cent BaS
In the hands of a careful operator the weights of the precipitated barium sulfate will check within 0.2 mg. on duplicate samples. Control Method
The writers have also worked out a rapid volumetric control method, by which it is possible to make a complete analysis in about 30 minutes. This method is believed to be extremely accurate. Weigh out 2 grams of the well-mixed sample, brush into a 400-cc. beaker, add about 250 cc. of hot water, and boil about 5 minutes. Filter a t once with vacuum through a Gooch crucible using a heavy asbestos pad about 5 mm. thick. Wash well with boiling water. The total volume of the solution should be about 600 cc. Transfer to an 800-cc. beaker; wash the flask well. Add 50 cc. of approximately 0.5 N sulfuric acid, boil the solution for a t least 10 minutes or until the odor of hydrogen sulfide is no longer detected. Then titrate with a solution of sodium hydroxide, which is just equal in strength to the sulfuric acid used above, using phenolphthalein as an indicator. This will give a very sharp pink end point. Subtract the number of cubic centimeters of sodium hydroxide used from the number of cubic centimeters of sulfuric acid used, add to this 0.5 cc., and then multiply by 2, which will give the percentage of barium sulfide.
August, 1926
INDUSTRIAI, AND ENGINEERING CHEMISTRY
By this method the water-soluble barium salt is converted to barium sulfate by the sulfuric acid and then the excess acid is neutralized with known strength sodium hydroxide. Results by this method check duplicate gravimetric determinations within 0.4 per cent. Phenolphthalein is used as indicator because the end point is sharper and more easily seen than with methyl orange. T h e 0.5 cc. added to the actual consumption represents the difference between the end points of phenolphthalein and methyl orange. The solution of sulfuric acid is standardized against sodium carbonate using methyl orange as an indicator.
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Calculation of Factor HgS04 B a s +Bas04 H2S 98.08 169.43 - = 43 1.7274 98.08 1 cc. H2SOa = 0.04 gram B a s We want - = O4 0 02316 1 7274 Therefore, 1 cc. HISO4 should contain 0.02316 gram in order that we may calculate percentage of BaS by multiplying (CC. Plus 0.5) by 2.
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Of course, other strengths of acid may be used, but for rapid control work the above strength simplifies calculations.
The Advance of Rayon’ By Otto Wilson WASHINGTON, D. C. MUNSEY BUILDING,
OR the chemist-economist few things are of more engrossing interest than to watch how, day by day, the great world of business swings more and more round (the laboratory as a center. One after another the industries .founded on a utilization of natural products are yielding place to the synthetics. Among the latest children of chemistry .to challenge the long-established prder is the new material which modern science has presented to the textile world, the fiber heretofore known as artificial silk but no%- christened by Americans “rayon.” For thousands of years wool, cotton, silk, and flax, the “big four” of the textile industry, provided the civilized and semicivilized world with clothing. Yet already, in an existence of only forty years, the new filament has sprung to a position ahead of one of them, and now occupies fourth place among the world’s great fibers. It has outstripped silk, and is looking ahead to the time when it will rival even linen and wool. In these rushing modern times we have grown used to the spectacle of gigantic industries springing up overnight. The rayon industry, in the suddenness with which it has appeared and the size it has attained, can claim kinship with that of the motor car, the motion picture, and the radio, and in one sense even takes precedence over them in that it serves one of the basic needs of the human race. The father of the rayon industry is generally conceded to be the French chemist, Count de Chardonnet, who introduced the first practicable process for spinning a cellulose thread in 1884 and exhibited manufactures from it a t the Paris Exposition in 1889. He lived to see his discovery blossom into one of the world’s great industries, his death occurring in 1924. For the first sixteen years following de Chardonnet’s announcement the history of the laboratory-born fiber was largely one of experimentation in a search for improved methods. But a t about the beginning of the present century three new processes were perfected and put in operation, and it is from that time that the commercial life of the synthetic textile really dates. Progress a t first was not rapid. At the outbreak of the World War the total world production was only about 26,000,000 pounds, and during the war years it did not increase spectacularly. Only in the last eight or nine years has it gone forward with great strides. Following is the statistical trail of its progress since the “outbreakof the war:
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Received June 30, 1926.
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1914 1918 1919 1920 1921 Estimated.
World Production of Rayon Pounds Pounds 26,000,000 1922 79 738 000 35,000,000 1923 97:OOO:OOO 141,414,000 40,000,000 1924 50,000,000 1925= 186,000,000 65,000,000
For the current year the estimate is for an output of about 245,000,000 pounds. This compares with an estimated world production of l , O ~ , O O O , O O O pounds of flax, 86,000,000 pounds of silk, 2,900,000,000pounds of wool, and 13,000,000,000 pounds of cotton. These figures are for the raw fiber, however. When they are reduced to a poundage of yarn or thread, the proper basis of comparison, rayon is seen to be not only far ahead of silk, but within hailing distance of linen and wool. I n the United States the production of rayon practically dates from 1912, when the first plant to be devoted exclusively to its manufacture was opened by the Viscose Company. Development was rapid, especially following the war, and this country is now the leading producer and consumer. American units have increased their output year by year, but they have never quite caught up with the advancing demand, and we have been obliged to draw on foreign sources to fill out our requirements. This phenomenal advance in this country and the world has been attended by the usual accompaniments of rapidly rising industries-the leaping forward in price of industrial stocks, an atmosphere of excited optimism, and confident forecasts of still more startling expansion which could hardly be realized. There are, indeed, a t the present moment many warning voices in the air advising caution. It is said that new production is outstripping demand, that the market will be overstocked, that many of the newly organized companies will find rough going. These statements may or may not be borne out by future developments. But even if they are proved sound the fact remains that if certain admitted defects of rayon textiles can be removed it would probably be hard to set a limit to the possible demand. Four distinct processes are at present being followed in the commercial production of artificial fibers. All of them start with cellulose and end up with a yarn of fine luster, but the chemical and mechanical steps in between, and the qualities of the resulting product, are different. 1-The original nitrocellulose process, invented in 1884 and still followed in the production of “Chardonnet” silks, involves
