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T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
are formed on t h e walls of t h e storage vessels. I t is necessary t o remove these deposits a t intervals of 2 t o 3 mo., as they contain an appreciable amount of ammonium salts.
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ume of liquid in the jar will have increased t o a liter, or more, from t h e ice introduced. After complete reduction, t h e zinc hydroxide is filtered off with suction, t h e filtrate cooled t o o o C., and sodium chloride SU M MA RY in an amount calculated t o saturate t h e volume of filThis permutit method of preparing ammonia-free t r a t e is added. A voluminous precipitate of phenylwater is applicable if distilled water is used. It has hydroxylamine is soon thrown down, which, after advantages over other methods of preparation in ease standing 1 5 min., is filtered off with suction and pressed Phenylhyof operation and production of large quantities a t mini- well between filter paper. (Caution: mum expense. The disadvantages of t h e method droxylamine is a violent skin poison. Rubber gloves a r e t h a t it gives a water of higher mineral content and should be worn and care taken of t h e face and eyes. does not remove nitrate, nitrite, or albuminoid nitrogen. Alcohol is t h e best remedial application.) The slightly damp phenylhydroxylamine is disInvestigations made t h u s far would indicate t h a t t h e solved in 500 cc. of ether and allowed t o stand over American permutit, except t h e prepared Folin permutit, will not quantitatively remove ammonia. night in a closed flask in contact with fused calcium German permutit has proved very satisfactory, and chloride. The ethereal solution is filtered through indications are t h a t t h e English permutit is equally filter paper, cooled t o o o C., and saturated with dry efficient. There is a possibility t h a t Refinite and ammonia gas, prepared by gently warming strong ammonium hydroxide and drying t h e gas evolved b y Boromite may possess similar properties. passing through one or more drying bottles packed A C K N 0 V'LE D G ME N T with broken sticks of sodium hydroxide. To t h e reThe author wishes t o express his appreciation t o sulting ethereal solution of t h e ammonium salt, 6 0 g. Prof. Edward Bartow, chief of t h e Illinois State Water of cold, freshly distilled amyl nitrite are now added all Survey Division, and t o Mr. R. E. Greenfield for their a t once. T h e vessel becomes filled with crystals of assisrance and criticism during t h e preparation of this cupferron and t h e temperature rises considerably, paper. some ether possibly boiling off (Hood). The precipit a t e is filtered a t t h e pump, washed with a little ether, NOTES ON THE PREPARATION OF CUPFERRON and spread on filter paper in a cool place t o dry. The By D. R. Kasanof cupferron thus obtained is best preserved in a wideGEKERAL CHEMICAL LABORATORIES, 25 W E S T 4 2 S T~, NEW ~ Y O R K , N Y. mouthed, glass-stoppered bottle, in which a lump of amReceived April 15, 1 9 2 0 monium carbonate is placed. This may be wrapped I n x-iew of t h e increasing importance of cupferron in filter paper and suspended by a cotton thread a t as a n analytic reagent, it is believed t h a t a slight tached with sealing wax t o t h e stopper. Amalgamated zinc dust may be used t o equal admodification of t h e method of preparation of Baudisch a n d King1 may be of assistance in securing a consis- vantage i n other similar reactions. tently good yield. The method commonly employed has its weakest link in t h e preparation of the phenylhydroxylamine, t h e yield of which varies from zero NOTE ON THE USE OF ALUNDUM FILTERING CRUCIBLES By D. T. Englis t o 7 0 per cent of t h e theory, depending on t h e quality DEPARTMENT OF CHEMISTRY, UNIVl3RSITY OF ILLINOIS, V R B kNA, ILLINOIS of t h e zinc dust employed. Poor yields are probably Received April 28, 1920 due t o a microscopic coating of zinc oxide on t h e surOne of t h e many uses of porous alundum ware is face of t h e zinc dust. The author has obtained a consistentIy good yield of phenylhydroxylamine from in filtering off cuprous oxide in t h e determination of reducing sugars. In a study made by Meade and nitrobenzene by using amalgamated zinc dust. Sixty grams of nitrobenzene are thoroughly emulsi- Harris1 on t h e determination of these sugars in cane fied by vigorous stirring in 700 cc. of water, contain- products, a very close agreement is reported between ing 30 g . of ammonium chloride, in a wide-mouthed comparative tests with Gooch and alundum crucibles, jar or a beaker of 1 . 5 t o 2 liters capacity. Eighty I n similar experiments made by t h e writer diffigrams of zinc dust are amalgamated with a 2 per culty was experienced in securing complete washing. cent solution of mercurous nitrate, acidified with a Even though t h e Sargent crucible holder was used few cc. of nitric acid. After stirring this mixture there was a tendency for t h e soluble alkali and copper for a few minutes t h e zinc dust is permitted t o settle salts t o climb t o t h e upper edge of t h e porous crucible and t h e supernatant liquid is poured off. The zinc and escape removal. Spencer's2 filtering apparatus dust is washed with water, under suction, until free would doubtless have eliminated this difficulty, b u t from acid, and may then be introduced without drying, since one of these was not a t hand it was necessary a small portion at a time, t o t h e nitrobenzene emul- t o resort t o some other method. sion. Vigorous stirring throughout is essential. The T h e procedure finally adopted was t o insert t h e temperature tends t o rise after each introduction of crucible in t h e Sargent holder, b u t with t h e flange t h e zinc dust paste and must be kept a t about 16' C. downward, as shown in t h e accompanying figure. by the introduction of chipped ice. All t h e zinc dust Washing was then carried out as completely as possishould have been added within one hour, and t h e vol1
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ble in t h e usual way. When all t h e soluble material had been removed, except t h e small amount in the upper rim. t h e c r i ~ r i h l ewas f l l d about half full of water, suction was applied a n d a moistened rubber stopper was quickly pressed down on top of t h e crucible. (The rubber stopper was always polished to a plane surface and washed free from any dust before using t h e first time.) As soon as t h e stopper was firmly held by t h e suction, water was poured on top of t h e holder (see figure) a n d around t h e stopper. T h e water drawn through t h e top rim easily completed t h e washing, as was indicated by t h e fact t h a t no test for alkalinity could be obtained b y addition of a drop of phenolphthalein t o t h e edge of t h e crucible. Continuous use of t h e crucible holder, since i t was not designed for treatment in this manner, tended t o crack t h e flange from t h e outer portion of t h e holder. A slight modification of t h e flange construction would perhaps lessen this difficulty. RAPID DETERMINATION OF SMALL AMOUNTS OF COPFER BY THE IODIDE METHOD By H. F. Bradley PARRCITY, UTAH Received April 5, 1920
The precipitate of cupric sulfide (containing not over 0.05 g. copper) is washed free from chlorides (complete removal of iron not being necessary), then moistened with a few drops of strong neutral zinc nitrate solution (free from chlorides), and ignited. T h e residue of zinc oxide and cupric oxide is quickly dissolved b y warming with I cc. of I : 2 hydrochloric acid. Neutralize with 5 per cent potassium hydroxide, acidify with acetic acid, add a little phosphate solution t o prevent t h e action of iron,l then add 2.5 g. solid sodium iodide and titrate as usual. SOME AMERICAN-MADE CHEMICAL REAGENTS By W. D. Collins BUREAU O F CHEMISTRY, u. s. DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C. Received March 31, 1920 I-POTASSIUM
PERRICYANIDE
A member of t h e AMERICAN CHEMICAL SOCIETYinformed t h e Committee on Guaranteed Reagents t h a t he had found potassium ferricyanide purchased a year or two ago wholly unsuited for use in making t h e gelatin test on tin plate. T h e salt made a turbid green solution. Examination of two lots which had been in t h e Bureau of Chemistry for several years showed t h a t 1
R. H. Deakin, Ckem. News, 118, 193.
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they were of t h e same quality, b u t a single recrystallization from a filtered solution gave a perfectly satisfactory product. Correspondence with manufacturers and dealers secured some analytical reports which indicated material of high purity. A sagnple furnished as representing t h e product now sold by one manufacturer made a perfectly clear I O per cent solution with no traces of green color and no precipitate. It therefore appears t h a t no one need now accept potassium ferricyanide which will not make a I O per cent solution without any precipitate or green color. Purification of poor material in stock is worth while in most cases. 11-METHYLO R A N G E '
Similar complaint was made t o t h e Committee of difficulty in procuring satisfactory methyl orange from American manufacturers. At t h e suggestion of t h e Committee, samples were purchased from four different sources. There was at hand for comparison one of a well-known foreign make. A sixth sample was obtained from a lot of methyl orange which was exhibited b y a manufacturer a t a meeting. A few grams of t h e best appearing sample (Sample A) were repurified by precipitating t h e free acid, filtering, dissolving with sodium carbonate solution, and recrystallizing twice. This produced shining crystal leaflets of a beautiful orange-red color which were provisionally adopted as a standard., The samples were judged b y general appearance, odor, water-insoluble residue from one gram in 400 cc. of water, and indicator value. T h e results are given i n t h e accompanying table. METHYLO R A N G E Waterinsol. IndicaResidue tor SAMPLE Appearance Odor from 1 g. Value Notes Standard Orange-red crystals None 0 , 0 0 0 0 Good A Orange-red crystals Very faint 0.0008 Good B Yellow-red powder None 0.0294 Good Foreign-made C Yellow-brown, lumpy1 Decided 0.0105 Good D Brown, lumpy Decided 0 . 0 5 3 7 Fair Dyestuff Strong 0 . 1 1 6 7 Good Naphthol-like E Brown powder odor F Yellow-red powder None Slight Good 1 A later sample from the manufacturer of C compared favorably with C O M P A R I S O N O F SAXPLES OF
B or F.
T h e odor resembled aniline in three cases, a n d one sample smelled strongly like naphthol. The two brown samples were not very pleasing in appearance. T h e manufactyrer of one of these products stated in reply t o criticism of his output t h a t i t was not intended for a n indicator b u t was sold for use as a dyestuff. A portion of Sample D was purified both by direct recrystallization and b y precipitating t h e acid a n d subsequently neutralizing t h e free acid with soda. I n each case a bronze-yellow crystalline powder was recovered which, in appearance, did not resemble t h e standard methyl orange. When used as an indicator its alkaline solution was bright yellow in color, b u t t h e acid solution was only pale red. Sample D did not give a clear solution when filtered. Notwithstanding t h e poor quality of some of t h e samples obtained, t h e results show t h a t i t is entirely 1
I n collaboration with G. C. Spencer.
