TJIE J O C R N A L OF I N D C S T R I A L A N D ENGINEERING C H E M I S T R Y
7’4
after it had been squeezed by hand and its moisture determined as described in the previous tests. The manner in which the color, size and alum .n-ere added and mixed was similar t o t h a t formerly employed, with the exception t h a t the total time of stirring was increased t o 3 0 min., and t h a t an excess of size and alum ( 2 and z 1 i 2 per cent. respectively) mere used in order t o set the heavy shades. Up to about 2 lbs. of dye the back-waters were practically coiorless. The method of preparing t h e hand sheets from the dyed stock was identical with t h a t used :n the previous series. The gradations in .shade of these papers were very distinct. and offered no difficulty in making a visual selection of tho sheets in tlqe order of t h e strength of dye employed. The tint photometer also gave uniform readings of color vhich are shorm grapliica!!y in Figs. ~ 5 ,6 , 7 . and 8 where “parts rcd, green and blue” and also “parts black“ are plotted against the strength of dye used. K‘liile we are not prepared t o say just hoix- the readings of the three colors should be interpreted or horn matching a shade could be facilitated from them, it is very evident t o us t h a t with this instrument a shade or tint may hr: given a definite numerical value. Fonssr PRODLXTSLUBORATORV MADISOX. TT’isco~irx
NOTES ON THE DETERMINATION OF ALUMINUM By C . F. SIDEXER AND EARLPETTIJOHN Received October :4, 1115
The determination of aluminum in the form of aluminurn oxide. after precipitation with ammonium hydroxide. is frequently made. I s ordinarily carried out. there are several points in t h e determination t h a t might give rise t o variations in results. The purpose of this piece o€ work is t o determine the best procedure mTith regard t o some of these points. I n looking up the literature on’ the subject of this precipitation, considerable difference of opinion was found. The ordinary directions are t o boil until the liquid just smells of ammonia, though it was very early discovered’ t h a t a t this point ammonium chloride may have hydrolyzed t o such an exten; with volatilization of ammonia t h a t the solution is actually acid. In this case, of course. aluminum hydroxide would be redissolved and quantitative results could not be obtained. L. Blum2 worked on this precipitation and found t h a t ammonium chloride was decomposed in solution a t 100’ C. with loss of ammonia; he advises filtration when t h e liquid is still quite strongly ammoniacal. He also states. and many others veriiy his statement, t h a t ammonium hydroxide dissolves a certain amount of freshly precipitated aluminum hydroxide! which amount is considerably lessened b y the presence of ammonium salts. C. F. Cross,3 using ammonium hydroxide solutions of varying strength, found t h a t aluminum hydroxide mas dissolved a t the moment of precipitation. t h a t the amount dissolved bore no I p
3
Z anal. Ciiem.. 2 , 394;I, 59 I b i d , 27, ! 9 . Chew Y m s , 39. : 6 . .
T‘ol. 8 , NO.8
relation t o t h e concentration o i the ammonium hydroxide, and t h a t ammonium salts lessened t h e solubility of t h e hydroxide. Penfield and Harper,’ in testing for dissolved aluminum hydroxide, found t h a t it -sas not present in t h e filtrate but was present in t h e n a s h water. They tried using, instead of boiling water, a n ammonium nitrate solution, made b y neutralizing 2 cc. of pure nitric acid with ammonia, and making u p t o IOO cc. With this washing solution they claim t h a t t h e precipitation can be made from solutions containing larger or sinaller amoun.ts of ammonium salts, and t h a t no very great care is needed in adding ammonia On a number of points, exactly opposite opinions as t o procedure are held. Hillebrand, in his h‘A4nalysis of Silicate and Carbonate Rocks.” states t h a t , contrary t o the usual belief. aluminum hydroxide i!; noi. volatile in presence of ammoniuin chloride. and t h a - , for the determination, nashing free from chlorides is unnecessary. Washi:igton, in his “Rock ?inalysis.” and hIahin. “Quantitative I? nalysis,” take t h e opposiw view: and say t h a t a1uminu.m hydroxide must hi: washed free from eT-ery tracc of chloride or low rcsults will be obtained. STith regard t o tioiling t h e solu tion for precipitation, the same difference of opinion exists. Washington advocates boiling ifor not morc t h a n I min.) mrith a slight excess of ammonia. n-hile Handy2 boils for 2 0 min. under the Sam:: circumstances. For washing the precipitate, a m monium nitrate is frequently recommended, Treatiwell, Penfield and Harper, Yashington a.nd others making use of it. RenzI3however, found t h a t when alumin u m hydroxide was precipitated with ammonium hydroxide in presence of ammonium nitrate, a small quantity remained in solution. Fresenius, Handy and several others advise the use of hot water There is a similar difference of opinion as t o t h e ignition of t h e precipitate. Allen and Gottschalk4 found t h a t the highest heat of the blast lamp was required t o effect complete dehydration: precipitates heated t o 1100’ C. and cooled for half an hour were still hygroscopic. Handy5 also considers the oxide .i.ery hygroscopic and advises intense ignition. Cariiel1e)r and on t h e other hand, obtained complete dehydration by gradual heating t o 850’ C. The points which this paper covers are a s follows: I-To determine whether t h e precipitate need be washed free from chlorides before ignition. 2-To determine whether a n excess of ammonia has a n y solvent effect on the freshly precipitated hydroxide. 3--To determine whether water or ammonium nitrate solution is more suitable for washing t h e prccipitate free from chlorides. 4-To determine a satisfactory time for ignition L O constant weight. An aluminum chloride solution was made up from 1
2 8 4 6 6
A m . J . S c z . , 20, 9, 181. J . A m . Chem. Soc.. 18, 766-82. J . Chenz. Soc. (London). 2 (19031, 729 Am. Chem. Jour., 24 (1900). 292-304. J , A m . C h e w . Soc., 18, 766-82. J . Chem. SOC.(London),Trans.. 63,S i .
Aug., 1916
T H E J O r R N A L OF I N D U S T R I A L A ND E S G I N E E RI LVG CH E M I S T R Y
sheet aluminum and hydrochloric acid. The ammonium chloride used volatilized without residue, as did t h e ammonium hydroxide. The ammonium hydroxide solution was filtered into a ceresin bottle: t h e specific gravity of t h e solution was 0 . 9 j j . I n all of t h e precipitations made with these solutions. the following general conditions were maintained: The volume of the solution from which t h e precipitation vias made was 2 5 0 cc. and in every case 2 j cc. of the total volume was a I O per cent solution of ammonium chloride. All precipitations were made in porcelain casseroles, the solution being boiled for I min. and filtered hot. The precipitates were ignited moist? in platinum crucibles: the ignited precipitates, after cooling somewhat in the air, were left in t h e desiccator for 20 min. before being weighed: t h e crucibles were covered while in t h e desiccator and on the balance. Twenty-five cc. of aluminum chloride solution were used in every case. The filtraze and wash water from each determination were evaporated separately and tested for t h e presence of aluminum. STRENGTH OF SOLUTIOS
The strength of t h e aluminum chloride solution was first determined in terms of t h e oxide. Two methods were used: ( I ) direct evaporation of t h e solution and ignition of Lhe residue; and ( 2 ) evaporation and ignition afzer adding enough ammonium hydroxide t o precipitate t h e aluminum hydroxide. TABLEI-STREICCTH OF ALUMINUMCHLORIDESOLUTIOS (1) Direct Evaporation of t h e Chloride 0 . 2303 0.2301
(2) Evaporation after Addition of Ammonium Hydroxide 0.2300 0.2302 0.2303
The results in Table I tend t o . show t h a t t h e same value is obtained if the chloride solution made ammoniacal is evaporated as if t h e pure chloride is evaporated. This result would hardly be expected if aluminum chloride is volatile under t h e given condition, since the amount of aluminum present as chloride is much less in t h e first case t h a n in the second. A slight loss might. however, occur in both cases so t h a t a second series of test determiflations was made. The amount of aluminum in terms of aluminum oxide was determined in a sample of Kahlbaum’s crystallized aluminum sulfate. A second series was run parallel t o this one, using some of t h e ’
TABLEI1 PER CEKT A1203 1X Aln(S0a)s Per cent Sample Alios KO. Grams Found 1 0.5841 17.24 2 0.6435 17.17 3 0.7018 17.1; 4 0.9150 17.18 5 0.9301 17.22 6 1.0571 17.17 , 1.2964 17.24
EFFECTO F NHaCl ON .11g(OH)s Sample Grams 0,5336 0,7723 0.9592 1.141, 0.9561 1.2990 1,6290
NH&l KH4OH Gram Cc. 0.3 5 0.3 5 0.3 5 0.3 5 0.5 5 0.5 5 0.5 5
P e r cent AlzOa Found 17.17 17,Ii 17.18 17.18 17.24 17.21 17.20
same sample. b u t , after solution in a little water, adding some ammonium chloride and enough ammonium hydroxide t o precipitate t h e aluminum as hydroxide. T h e results, in Table 11, show t h a t there is no loss b y volatilization of aluminum chloride when the precipitated hydroxide is ignited in presence of ammonium chloride.
E F FEC T
0F
715
V A R YI N G -A 31RI 0 X I UM H Y D R O X I D E
The next point taken u p was the effect on t h e precipitation of .varying the amount of ammonium hydroxide present. Water was used t o transfer the precipitate from the casserole t o t h e filter paper, as small an amount as possible being used. I n no case did the wash water show a test for aluminum, while t h e filtrate from those determinations giving low results did give a test for aluminum. The results appear in Table 111. TABLE 111-EFFECT Very Slight Excess 0.2303 0.2302 0.2298 0 2297 0.2299 0,2305
EXCESS
OF OF AMXONICM HYDROXIDE IN T I O N O F ALUXIICUM HYDROXIDE
10 cc. Excess 0.2281 0.2271 0.2282 0.2304 0.2304 0,2283
15 cc.
Excess 0.2294 0.2289 0,2294 0,2297
0.7274 0.2282
PRECIPITA-
20 cc. Excess 0.2288 0.2305 0.2302 0.2287 0.2291 0,2265
The uniformity of results in the first column is very evident, as compared with t h a t of t h e other three, although the uniformity there is not as great as desired. ,4n excess of ammonia has a decided solvent effect, not proportional t o t h e excess of ammonia added. The variation in results obtained in each of the other three columns must be due t o very slight variations in procedure, such as time of filtering. The results in Column I check those obtained in evaporating the.solution in a platinum crucible, as was t o be expected. E F F E C T O F WASHIPjG P R E C I P I T A T E F R E E
OF C H L O R I D E S
On the effect of washing the precipitate free from chlorides, the results in Table IV were obtained. TABLE I\‘-EFFECT Hot Water 0,2285 0.2281 0.2280
O F WAS€IIiXG ALUMINUM H Y ~ R O X I D F ER r F F R O M CHLORIDESB Y VARIOUSWASHES 1 P e r cent 2 P e r cent 3SH4NOa Per cent NH4NOa KH4Nos Solution Solution Solution 0.2277 0.2262 0.2263 0.2286 0.2263 0.2276 0.2286 0.2262 0.2282
For the pvrecipitations, j cc. of ammonium hydroxide were added, about 2 cc. of this being in excess. I n no case was aluminum hydroxide found in the filtrate. I n t h e first series, in all three cases, t h e wash water gave a test for aluminum hydroxide. I n t h e second experiment t h e precipitate obtained was filtered off, ignited, and found t o weigh 0 . 0 0 2 2 g., which brings the total weight of t h e precipitate u p t o t h e value 0.2303 g. formerly obtained. I n every experiment t h e wash water was tested for aluminum and it was found t o be present, so t h a t t h e final conclusion was t h a t ammonium nitrate solution. as used, was unsatisfactory €or washing purposes. E F F E C T O F BLASTIh-G
Ih- V A R I O U S W A Y S
For heating the precipitates t o constant weight an ordinary blast lamp was used. The amount of air used and t y p e of lamp might change t h e results obtained. T h e first precipitates were blasted for I O min. periods until constant weight was obtained. Typical results appear in Table lr. The weights given indicate the weight in grams of crucible and precipitate. It is seen t h a t three Io-min. periods or two 20-min.
j16
T H E .70l’RYAL OF I-VD17STRIAL A X D E S G I N E E R I S G C H E M I S T R Y
YO].8 , SO.8
periods sen-ed t o effect a constant weight. Slight differences are undoubtedly produced by the size: weight ant? thicliness of the crucible.
11-Soap Powders proper, a mixture consisting of 1-arious proportions of sodium carbonate and soap: the soaps used are commonly prepared from cottonseed TABLEV-TIX~ R ~ Q U I R Em D HEATINGALUMINA TO CcmsThsr KEIGHT soap stock and h a w as a filler sodium carbonate, Time No. No. No. No HEATEDI N 2 0 - 1 1 1 N . P E R I O D S which itself is a water softener of great value. hlin 1 2 3 4 20 min. 40 min. 60 min. 111- scouring Powders! which contain an abrasive 10 3 6 . 9 6 2 0 29.6670 21.0587 29.6647 29.6538 29.6530 29.652; 20 36.9615 2 9 . 6 6 5 3 21.0570 29.6638 33.7635 33.7627 3 3 . 7 6 2 5 and soap either with or without the addition of sodium 30 36.9605 2 9 . 6 6 4 3 21.0569 29 6638 3 3 , 7 7 6 0 3 3 , 7 7 6 0 . . . . . . . carbonate. 40 36 9609 29 6643 . . . . . 36.9621 36.9602 3 6 . 9 6 0 2 29.6730 29.6730 29.6730 I n this article are described various experiments One precipitate was given a special series of blast- which h a r e been conducted on the soap powders proper. ings t o determine whether or not t h e alumina was The basic scheme used is t h a t given by Leflmann in hygroscopic after t h e blasting. The results (Table Allen’s “Commercial Organic -4nalysis.” During our T I ) indicate t h a t this change in Tyeight was very largely studies. Dr. Leeds published a scheme for the analTABLE vI--sHOD’ISG HYGROSCOPIC PROPERTY OP 241,1-MISA ysis of soap. which is quite similar t o the one used b y Weights us for the analysis of soap powders. Additions and Constant weight obtained (cruc. 1 .p p t . ) . . 21.0598 L e f t 6 d a y s in t h e desiccator. . . . . . . . . . . . . 21.0636 modifications t o the older schemes were made as the Blasted 10 m i n . . . . . . . . . . . . . . . . . . . . . . . . . 21.061 1 After 24 hrs. blasted 20 m i n . . . . . . . . . . . . . . . . 21.060:. work progressed. and it is t o aid t h e soap analyst After 24 hrs. blasted 20 m i n . . . . . . . . . . . . . . . . 21.0604 t h a t important details are described. After 24 hrs. blasted 20 m i n . . . . . . . . . . . . . . . . 21 .(:602 Blasted a second 70 m i n , . . . . . . . . . . . . . . . 21.0598 Left covered in t h e balance case 24 h r s , . . . . 2 1 , 0 6 2 4 Our purpose in presenting this paper is t o offer o u r experience t o those interested in the analysis of soap due l o t h e precipitate, since a platinum crucible treated we do so because t h e particular problems powders. and in much t h e same \yay did not change appreciably we have found are not discussed in t h e form t h a t I s in weight. desirable for those who have similar problems t o solve, c o K’CL u SI 0 N s I--Boiling for I min. completely precipitates al! aluminum present, and longer boiling may lead t o a re-solution of part of it. 11--Sluminurn hydroxide need not be washed free from ammonium chloride before ignition. 111-The excess of ammonia present when precipitation is made should be as.smal1 as possible and never more t h a n I or z cc. in z j o cc. of solution. IT-Aluminum hydroxide freshly precipitated is soluble t o a slight extent in water and t o about t h e same extent in dilute ammonium nitrate solution. V-The precipitated hydroxide, when large, must be blasted 40 min, t o insure its being reduced t o a constant weight. ’C’I---The ignited alumina is strongly hygroscopic. SoTE-Since this paper was written a paper has been published by IT. H. D a u d t . THIS J O U X S A L , 7 (191 j): 847, confirming what we ha\Te found t o be true regarding t h e presence of ammonium chloride a t the time of ignition. CHEMICALLABORATORY. I:.I.IVERSITY MIXXEAPOLIS
OF
MINNESOTA
THE ANALYSIS OF SOAP POWDERS By LOUISROSENBERG - 4 3 0 VICTORLENHER R e c e i w d F e b r u a r y 7, 1916
During recent years great progress has been made in those industries which supply cleansing materials. The advent of t h e modern mashing powder has brought into the household a coni-enient, economical cleanser. The powders which to-day are in common use divide themselves into three general classes: I-So-called Xashing Pom-ders. composed of trisodium phosphate, borax, or a mixture of various proportions of sodium carbonate and bicarbonate: it is obvious from the composition of these powders t h a t their main efficiency lies in their ability t o soften t h e water used.
3.1 01S T U R E
The ordinary methods for determining n-ater in soap are not satisfactory when applied t o washing powders. Experiments have repeatedly demonstrated t h a t heat,ing a Io-g. sample a t I o j ” C. until the weight becomes constant ‘is worthless, for the odor of decomposing soap is usually observed before this temperature is reached. When heated for I hr. t o 105’. most of t h e soap powders give off a strong odor of decomposed soap. hence the determination is of little value. Further, the soap powder upon heating t o 1 0 5 ’ frequently forms lumps which prevent complete drying: even if a weighed glass rod is used t o break u p the lumps. it is difficult t o keep the sample from caking. i n powders iyhich contain as high as 30-40 per cent water, spattering frequently occurs. Leff mann’s suggestion for soap--that the drying be done on a sand bath--is useless with many powders, inasmuch as even with the greatest care. decomposition takes place. The methods in use for the determination of moisture in a higligrade stearic acid soap are unsatisfactory, as they frequently fail entirely when applied t o soap powders containing cottonseed soap stock or lonT-grade tallow soap. T h e method of %ahrion. in which the sample is heated with three times its weight of oleic acid until a clear solution is obtained. indicating the removal of the water, was found t o be inapplicable, as difficulty was experienced in determining when t h e solution became clear. The recommendation of Fahrion, t o heat the sample (to which has been added oleic acid) in a platinum dish over a free flame, ‘Tiras also tried with the soap powders, b u t even with t h e greatest care decomposition of the soap took place. On a sand bath the powder soon decomposed. Sample I , containing actually 37.8 per cent of water, was used in experimenting mTith oleic acid in order t o test this method for moisture. Six samples of 2 g. each were
