INDUSTRIAL a n d ENGINEERING CHEMISTRY
A N A LY T IC A L E D I T I O N
H ARRISO N E. HOW E, E D IT O R
»
ISSU ED A P R IL 15, 1942 » V O L. 14, NO. 4 ♦ C O N S E C U T IV E NO. 8C olorim etric D e te rm in a tio n of P h o sp h o ru s in Iro n O r e ... E. John Center and Hobart H. Willard 287 F ilte rin g Device for V iscosity T u b e s ...
Stanford J. Hetzel 288 C olorim etric D e te rm in a tio n of Nickel w ith A m
m o n ia ... J. P. Mehlig 289 A nalysis of C ellulose D e r i v a t i v e s ...
Carl J. Malm, Gale F. Nadeau, and Leo B. Genung 292 D e te rm in a tio n of S tro n tiu m in Presence of C alcium
Paul B. Stewart and Kenneth A. Kobe 298 A nalysis of T e rn a ry S y stem E th a n o l-M eth a n o l-
W a t e r ... John Griswold and J. A. Dinwiddie 299 R apid M e th o d for D ete rm in in g P o ta ssiu m in P la n t
M a t e r i a l ... J. L. St. John and M. C. Midgley 301 D ete rm in in g F u s a in C o n te n t of Illinois Coals . . .
B. C. Parks, G. W. Land, and O. W. Rees 303 Expected Service Effectiveness of Preservative T re a t
m e n ts A pplied to M il lw o r k ...
John B. Mellecker and Merle W. Baker 305 C olorim etric D e te rm in a tio n of D ieth y lstilb estro l .
Manuel Tubis and Albert Bloom 309 S p e c tro p h o to m e tric E s tim a tio n of P entachloro-
p h en o l in T issues a n d W a t e r ...
Wilhelm Deichmann and Lawrence J. Schafer 310 D e te rm in a tio n of N i t r i t e s ...
N. F. Kershaw and N. S. Chamberlin 312 D e te rm in a tio n of S m all A m o u n ts of Iodide in
P h o to g ra p h ic D e v e lo p e rs ...
R. M. Evans, W. T. Hanson, Jr., and P. K. Glasoe 314 D ete ctin g B asicity in S lig h tly S oluble M aterials . .
Fritz Feigl and Coriolan P. J. da Silva 316 P o te n tio m e tric D e te rm in a tio n of V ita m in C . . .
J. B. Ramsey and E. L. Colichman 319 E lim in a tio n of W ater Wave in P olarographic Work
a t R elatively H ig h In d iffe re n t E lectrolyte C on
c e n tra tio n s . . . I. M. Kolthoff and E. F. Orlemann 321
Specific G ravity of P e tro le u m Oils by F allin g Drop M e t h o d ... A. J. Hoiberg 323 D e te rm in a tio n of D rying R a te s of T h in F ilm s . . .
George Rieger and C. S. Grove, Jr. 326 C o n stru c tio n a n d O p eratio n of P o laro g ra p h . . . .
N. HowellFurman, Clark E. Bricker, and E. BruceWhitesell 333 R o tary V iscom eter for D e te rm in a tio n of H igh C o n
sistencies ...
R. N. Traxler, J. W. Romberg, and H. E. Schweyer 340 A u to m a tic M eth o d for C lean in g T a r D istilla tio n
F l a s k s ... William Pechenick 344 A p p aratu s for D istilla tio n of Corrosive L iq u id s as
Used for P u rific atio n of C hlorosulfonic Acid . . . Arthur W. Hixson and Alvan H. Tenney 345 New A ll-G lass M i l l ... David B. Pall 346 D ialyzing C o n c e n tr a to r ...
Carl C. Smith and Charles D. Stevens 348 M ICROCHEM ISTRY:
P h o t o e l e c t r o m e t r i c P a r t i d e - C o n c e n t r a t i o n A n a ly s is ...
William Seaman, A. R. Norton, and Charles Maresh 350 F uzz D etecto r for V iewing G lass W eighing Vessels
in O rganic Q u a n tita tiv e M icroanalysis . . . . Douglass F. Hayman and Wilhelm Reiss 357 S em im icro ch em ical Assay for D ie th y lstilb e stro l .
C. W. Sondern and Clarence Burson 358 S e p ara tio n of Copper, Lead, a n d Z inc w ith S alicyl-
a ld o x im e ... L. P. Biefeld and W. B. Ligett 359 Color R eactions of O rganic N itro g en C o m p o u n d s
w ith S elenious A cid -S u lfu ric Acid S o lu tio n . . Bartlett T. Dewey and Albert H. Gelman 361 M odified M icro p ip et for D ensity D e te rm in a tio n s
in Heavy W ater A n a l y s i s ...
Fred Rosebury and W. E. van Heyningen 363 P h o to m e tric D e te rm in a tio n of C opper a n d Iro n in
D istilled L i q u o r s ...
L. Gerber, Ralph 1. Claassen, and C. S. Boruff 364
T h e A m erican C hem ical Society assum es no responsibility for th e sta te m e n ts a n d opinions a d v an ced b y co n trib u to rs to its p u b licatio n s.
26,200 copies of th is issue p rin te d . C o p y rig h t 1942 b y A m erican C hem ical Society.
P u b l i c a t i o n O f f ic e :
E d i t o r i a l O f f i c e : 1 1 5 5 1 6 t h S t r e e t , N . W „ W a s h i n g t o n , I ) . C . T e l e p h o n e : R e p u b l i c 5 3 0 1 . C a b l e : J i e c h e m ( W a s h i n g t o n )
P u b lish e d b y th e A m erican C hem ical Society, P u b lica tio n Office, 2 0 th &
N o rth a m p to n S ts., E a s to n , P e n n a . E n te re d as second-class m a tte r a t the P o s t Office a t E a s to n , P e n n a ., u n d e r th e A ct of M arch 3, 1879, as 24 tim es a y ear. In d u s tria l E d itio n m o n th ly on th e 1 st; A n aly tical E d itio n m o nthly on th e 15 th . A ccep tan ce fo r m ailing a t special r a te of p ostage provided for m Sectio n 1103, A c t of O ctober 3, 1917, au th o riz e d J u ly 13, 1918. .
A n n u al su b sc rip tio n ra te , In d u s tria l E d itio n a n d A n aly tical E d itio n sold only as a u n it, m em bers $3.00, o th ers $4.00. Foreign p ostage to countries n o t in th e P a n A m erican U nion, $2.25; C an ad ian postage, $0.75. Single
E a s t o n , P e n n a .
A d v e r t i s i n g D e p a r t m e n t : 3 3 2 W e s t 4 2 n d S t r e e t , N e w Y o r k , N . Y . T e l e p h o n e : B r y a n t 9 - 4 4 3 0
copies: In d u s tria l E d itio n , $0.75; A n a ly tic al E d itio n , $0.50. Special ra te s to m em bers.
N o claim s can be allow ed for copies of jo u rn a ls lost in th e m ails unless such claim s are received w ithin 60 d a y s of th e d a te of issue, a n d no claim s w ill be allow ed fo r issues lo st as a re s u lt of insufficient n o tice of change of ad d ress. (T en d a y s' ad v an ce n o tice req u ire d .) "M issin g fro m files"
c an n o t be accepted as th e reason for hono rin g a claim . A ddress claim s to C harles L. P arso n s, B usiness M anager, 1155 16th S tre e t, N . W ., W ash in g to n D . C., U. S. A.
L E E D S
&.
NORTHRUP COMPANY, 4920 STENTON AVE., P H IL A . PAM E A S U R IN G IN S T R U M E N T S » T E L E M E T E R S . A U T O M A T IC C O N T R O L S • H E A T - T R E A T IN G FURNAcES P ro g ram Control is one of the new er ideas now d ra fte d by chem ical, food, glass and I other process industries to help secure the fast, >
accurate, autom atic h e atin g required for to
day ’s accelerated production.
Want To “ Bend” A Temperature For Better Heating?
In sta rtin g a batch, one o f these controllers first ; uses on*off valve m otion, in response to temperature j o f fu rn ac e ; th e re it sh ifts to th ro ttlin g (proportional position and floating) control, based on material. ; tem p eratu re. T h e ra te o f h eating, ra te of cooling j a n d tim e of soaking are autom atically held as set, j unless u ser sw itches o il these features.
P ro g ram Control is an im provem ent over , the usual control, w hich considers only the m axim um or soak tem p e ra tu re; because Pro
g ram Control regulates the rates of heating j and cooling, as w ell as the maximum. Ths ; record on the pyrom eter c h art rises at a"?
desired rate, “bends” a t the desired soak tem
p e ratu re, holds the soak as long as is speci
fied, and then “bends” dow n ag ain into a con- j trolled cooling cycle, to complete the program 5 w hich w ill best fit the product for w a r’s needs. j
In this strenuous “ t e m p e r a t u r e - b e n d i n g 1! j various M icrom ax ch aracteristics are impor' tan t, but p o s s i b l y the most useful one i s lts f micro-responsiveness. M icrom ax acts superior speed-plus-precision on the siitd j fluctuations of tem p eratu re. E ven before the«
fluctuations a re b ig enough to show on the ch art— therefore, even before the best furnace op erato r could act— the M icrom ax acts. Th»
m icro-responsive h a n d lin g of tiny change' heads off the big sw ings— throttles them * th at they nev er develop. M icromax hoi s tem perature w ith the steadiness needed f°r unifo rm ity of product.
M icrom ax P ro g ram C ontrol uses standar- instrum ents, gro u p ed at our p lan t to meeti' in d iv id u a l need. I f you h av e a problem a te such lines, we’ll be g lad to try to help -'f‘
w ith it, on request.
Jrl Ad EN-0600B(15)
A n E lectro-C hem ograph, w hich records the analyses of a dro p p in g -m ercu ry electrode, being used by M erck & C o . Inc. research lab.
2 4 -H O U R ANALYSIS NOWTAKES10MIN.
In A Merck Laboratory
A p a rtic u la r type of an alytical procedure for a certain vitam in co n stitu e n t fo r
m erly required 24 hours in the research laboratories of M e rc k & Co., Inc., m akers of fine chemicals, d ru g s and vitam ins. A nalysis w a sn ’t, of course, an every-second- on-the-job ta sk ; b u t M e rc k ’s m en n a tu ra lly w an te d to speed up the operation, provided an accurate, not-too-com plex m ethod could be found.
T h e r e w as, therefore, m uch interest in the electrochem ical researches of P rofessor H eyrovsky, especially w hen th e L & N E lectro-C hem ograph w as developed to p ro
vide autom atic records of the dropping-m ercury electrode’s c u rre n t and potential.
A fte r investigation, M e rc k secured one of these in stru m en ts and p u t it to w ork.
R esults are m ost satisfactory. T h e 24-hour analysis now takes 10 m inutes, and resu lts check w ith “ w e t” m ethods. T h e r e ’s no highly sensitive g alvanom eter to consider; and no developm ent of photographic records . . . the record appears, in ink, 011 the M ic ro m ax ch a rt, as the analysis proceeds. I f the su p p o rtin g electrolyte isn’t correct a t first, as m ay w ell happen in non-repetitive w ork, th a t fact shows im m ediately and can be corrected.
T h e E lectro-C hem ograph can be used for inorganic as w ell as organic w o rk , and for qualitativ e o r q u a n tita tiv e analyses. I t is described in T e c h n ic a l P ublication E -94 ( 1 ) . O u r R e p rin t E -9 4 ( 1 ) from T rans. E lectrochejn. Soc. V ol. L X X V I , 1939, contains f u rth e r discussion. A bibliography listing 825 papers on dropping- m ercury-electrode w o rk is also a v a ila b le ; it is o u r B ibliography E -9 4 ( 1 ). A ny one o r all three publications w ill be sent 011 request.
April 15, 1942 A N A L Y T I C A L E D I T I O N 5
Exchequer standard W i n c h e s t e r b u s h e l
of H e n r y V l l ¿
S T A N D A R D ALL OVER U. S.
Wherever A. R. chemicals are used, Mallinckrodt Analytical Reagents are known for unquestionable dependability— made to predetermined standards of purity which assure more accurate results in gravimetric, gasometric, colorimetric, or titrimetric analysis.
Catalogue of Mallinckrodt Analytical Reagents and other laboratory chem i
cals yours on request.
A L W A Y S S P E C I F Y R E A G E N T S IN M A N U F A C T U R E R ’S O R IG IN A L P A C K A G E S
MALLINCKRODT CHEMICAL WORKS
ST. L O U IS • P H IL A D E L P H IA • M O N T R E A L
C H IC A G O • NEW Y O R K • L O S A N G E L E S
6 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
PYREX
B R A N DÎPYREX]
LABORATORY WARE V means---
Research in Glass
“ S ®
U » « ¥ uW
Pvrex West Type
* B R A N D mI AImproved Condensers
A V A I L A B L E I N C O M P L E T E S I Z E
R A N G E — 1 0 0 m m . t o 7 5 0 m m .
P y r e x b r a n d W e s t T y p e C o n d e n s e r s a r e d e s ig n e d fo r s p e e d , e c o n o m y a n d c o n v e n ie n c e . A ll o n e p ie c e , f a b r i c a t e d fro m b a l a n c e d P y r e x b r a n d C h e m ic a l G la s s N o. 7 7 4 , t h e s e c o n d e n s e r s s a v e y o u tim e , m o n e y a n d a n n o y a n c e . T h e ir im p r o v e d d e s i g n p e r m its u s e of a lig h t w a ll i n n e r t u b e ( p la in o r in d e n te d ) a n d a h e a v y
w a ll o u te r ja c k e t w ith m in im u m s p a c e b e t w e e n , a s s u r i n g th e r m a l r e s is ta n c e a n d m e c h a n i c a l s tr e n g t h p lu s f a s te r c o o lin g . L a b o r a t o r ie s r e p o r t m in im u m b r e a k a g e i n u s e . T h e y c o m m e n t m o st f a v o r a b ly o n t h e c o n v e n ie n t f e a tu r e s — n o a s s e m b ly o r d is a s s e m b ly , tu b u la tio n s o n s a m e s id e of th e j a c k e t a n d to o le d a d a p t e r e n d s .
" P y r e x " W e s t T y p e C o n d e n s e r s a r e a ls o a v a il
a b l e w ith i n t e r c h a n g e a b l e T jo in ts . T h e c o m p l e t e lin e , a s d e s c r i b e d i n C a ta lo g L P 2 1 , is a v a ila b le t h r o u g h y o u r la b o r a to r y s u p p ly d e a l e r .
" P Y R E X " a n d " V Y C O P ." a r c r c g h l c r ' d tra d e-m a rks a n d in d ic a fe m anufa cture b y •
CORNING GLASS WORKS
C O R N IN G , N . Y.
April 15, 1942 A N A L Y T I C A L E D I T I O N 7
C o m p a n y _________________________________________________________________
[P le a s e a tta c h to , o r w rite o n , y o u r c o m p a n y l e t t e r h e a d ]
IT'S no secret that freq u en cy control of many oscillating electrical circuits em ployed in vital defense apparatus rad io transm itters an d receivers, aircraft beam indicators, aircraft and subm arine d etectors— depends upon quartz crystals.
No secret either, is the fact that hair-line accurate measuring methods to check the electrical a x e s of the crystals are of extrem e im portance in the manufacture of these control units. Using the G - E XR D Unit, manufacturers have found in x-ray diffraction a satisfactory method of analyzing uncut crystals and determ ining the proper direction of cutting. X -R a y diffraction d oes the ¡ob faster, fa r more accu rately than ever before, and contributes a valuable saving of both time and m aterial.
The XRD Goniom eter Assem bly illustrated below is one of several types o f highly efficient instruments used by q uartz crystal manufacturers. The G -E X R D Unit is d esig n ed for precision research an d control a n a ly se s. It em b od ies the safety, convenience, flexibility, e a se o f operation, and ad ap tab ility that a re required fo r effective utilization of the x-ray method.
Modern, progressive analytical labo rato ries have been quick to recognize the G - E XRD Unit as a d ep e n d a b le "problem solver." If, in your laboratory, you h ave a problem that has you stumped, w hy not do this: Use the convenient coupon to request full information about the G - E XRD Unit and its application to your problem . The services of o ur X-Ray Diffraction Labo rato ry staff a re yours for the asking;
ad dress your request to Department R44.
■SIGN a n d M A IL , T O D A Y -
P le a se se n d me co m p le te in fo rm a tio n a b o u t the G - E XRD X -R a y D iffraction U n it a n d its a p p lic a t io n to a n a ly t ic a l p ro b le m s.
N am e
Position.
GENERA L f f ELECTRIC X-RAY C O R PO R A T IO N
2 0 1 2 J A C K S O N B L V D . C H IC A G O , l i t . , U . S . A .
I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
S E T T I N G T H E P A C E I N C H E M I C A L P U R I T Y S I N C E 1 8 8 2
T V 1 W K jU U f& ttJ
B a k e r A d a m s o n
D iv is io n of G E N E R A L C H E M IC A L C O M P A N Y , 4 0 R e c to r St., N e w Yo rk L . H / f c Û ï S
Sales O ffic e s : A tla n ta • B altim o re • B oston • B rid g e p o rt (C o n n .) • B uffalo • C h a rlo tte (N . C .) • C hicago • C leveland D en v er • D e tro it • H o u sto n • K a n sa s C ity • M ilw aukee • M in n eap o lis • N ew Y o rk • P h ila d e lp h ia • P it ts b u r g h
P ro v id en c e (R . I .) • S t. L o u is • U tic a (N . Y .) P a c ific C oast S a les O ffic e s : S a n F ra n c is c o • L os A ngeles P a c ific N o r th w e s t S a lés O ffic e s : W e n a tc h e e (W a sh .) • Y a k im a (W a sh .)
— ---In C a n a d a : T h e N ichols C hem ical C o m pany, L im ite d • M o n tre al • T o ro n to • V a n c o u v e r---
• • • it m ig h t c o s t o u r A rm y h u n d r e d s o f liv es. B u t t h a n k s to a d v a n c e d f a b r ic a tin g m e th o d s , th e A rm y ’s s p e c ia l “ A s s a u lt” w ire is b u i l t to “ ta k e it!'
B & A R e a g e n ts p la y a n i m p o r t a n t p a r t in th e p r o d u c ti o n o f su c h p r o d u c ts . T h e y a r e r e g u l a r l y h e l p i n g to c o n t r o l q u a l i t y in th e c o p p e r in d u s
tr y . In fa c t, i m p o r t a n t p ro -
d u c e r s h a v e s ta n d a r d iz e d o n B & A R e a g e n ts ! F r o m a c c u r a te d e t e r m in a tio n s in o r e s a m p le s o r c o n c e n tr a te s . . . a ll th e w a y th r o u g h to c o p p e r a n d c o p p e r a llo y f a b r ic a tio n . . . m e ta llu r g ic a l c h e m is ts re c o g n iz e t h e d e p e n d a b ili ty , p u r i t y a n d u n if o r m ity o f B & A R e a g e n ts .
W h e n q u a l ity c o u n ts , B a k e r & A d a m s o n R e a g e n ts a re s e le c te d to d o th e j o b !
NORTON LABORATORY WARE Distributed by the following:
C e n t ra l S cie n tific C o ., C h ic a g o a n d O t h e r C itie s
E im e r a n d A m e n d , N e w Y o rk C it y F is h e r S cie n tific C o ., P itts b u rg h A rth u r H . T h o m a s C o ., P h ila d e lp h ia E . H . S a r g e n t & C o ., C h ic a g o
B ra u n C o r p ., l o s A n g e le s B ra u n , K n e ch t, H e im a n , S a n F ra n c is c o
O r s im p ly o r d e r th ro u g h y o u r f a v o r it e L a b o r a t o r y S u p p ly H o u se
April 15, 1942
Prepared in cooperation with the technical and research staff o f N O R T O N C O M P A N Y , Worcester, Mass.
U se rs of ALU N D U M Crucibles Develop Ea sy W ays to Clean and R e sto re P orosity
Cleaning Alundum Crucibles B y Philip B. H erm an
Osborne-M cM illan E levator Co.
M inneapolis, M innesota Users of A L U N D U M crucibles for fil
tering and subsequent ashing of residues in the crucible have probably noticed that, after a num ber of such filtrations and ashings, filtering becomes m uch slower and a t tim es th e q u a n tity of liquid being sucked through th e crucible is almost negligible. Ashing of th e crucible does n ot seem to im prove th e situation any.
I f th e crucible is placed in a bath of concentrated hydrochloric acid for sev
eral hours, thoroughly rinsed, and then dried, filtration is improved very much.
Possibly minerals from the m aterials ashed in the crucible, such as animal feeds, have filled the pores of the cruci
ble and hence cu t down th e ra te of filtra
tion. The acid trea tm e n t thus dissolves the m ineral m a tte r and opens the pores of th e crucible again.
I t had been the practice in this lab
oratory to discard A L U N D U M crucibles when they did not filter rapidly. B y the above trea tm e n t th e life of a crucible has been quite a b it prolonged. From
“ Chem ist A nalyst,” Vol. 30, No. 2.
Restoring the Porosity of Alundum Crucibles By L. M. Nixon
N. C. D epartm ent of Agriculture Raleigh, N. C.
In routine analytical work where A LU N D U M crucibles are used for filter
ing or extracting it will be found th a t the pores of th e crucibles gradually become clogged and they filter so slowly th a t it m ay be necessary to discard them.
However, b y giving them the follow
ing treatm ent when necessary, their porosity can be restored and they can be used indefinitely. F irst, destroy any organic m aterial th a t m ay be present by igniting the crucibles a t a dull red heat.
L et them cool and place for a few m in
utes in a boiling 25% solution of NaOH.
Wash thoroughly w ith hot w ater to remove the N aO H and let them stand immersed for 20-30 m inutes in a 1-3 solution of hydrofluoric acid. W ash out thoroughly w ith hot w ater and they are again ready for use. If they are not badly clogged, it m ay not be necessary to boil them in the N aO H solution.
From “ Chemist A nalyst,” Vol. 25, No. 1.
Excellent Results in Igniting, Incinerating and Melting A LUN D U M Ignition Crucibles are used in general laboratory practice to day where an ignition of' carbonaceous material, such as the ashing of coal, is involved. The special capsule shapes speed up these operations considerably.
P. S. These p articular crucibles and capsules cannot be used for alkali fusions.
New Norton Laboratory Ware Catalog Contains Complete Data All th e facts and figures on A L U N D U M L aboratory W are, com plete speci
fying d a ta and list prices are found in the new catalog, “N orton R efractory L aboratory W are.” F or instance, if you are looking for A L U N D U M In cin e ra t
ing Dishes, they are described in the following m anner:
ALUNDUM IN C IN ER A T IN G D ISH ES STO C K SIZES
No. Dimensions D ep th L ist Price 6936 4 % " square 1" -$ 1 .2 0 6400 2 % " diam. % " .60
S PEC IA L SIZES
22345 4 " x 8 M " H " 5.30 6954 4 " x 9 M " *A" 4.40 9671 6 ^ " x \2 % " 2| g " 8.80 14066 1 1 " x 16" 2 K " 16.15
P. S. Such an inform ative catalog is a great help in purchasing laboratory ware. Send for your copy to d ay , ad dressing N orton Com pany, W orcester, M assachusetts.
NORTON RESEARCH
INGREDIENT NUMBER ONE IN FUSED ALUMINA LABORATORY WARE
10 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
A .H .T . CO. S P E C IF IC A T IO N
F LU O R E S C E N T DAYLIGHT LAMPS
Based on new fluorescent daylight bulb w h ich gives a cold diffused, glareless light sim ila r to n atu ral daylight
: ■■■■ . . ' i!
2072-F. 6323.
L A B O R A T O R Y L A M P S , F l u o r e s c e n t D a y lig h t. B a s e d o n n e w 1 5 - w a tt f lu o re s c e n t b u lb , 18 in c h e s lo n g , g iv in g a c o ld , d iffu s e d , g la re le s s lig h t w ith c h a r a c t e r is ti c s s im ila r t o n a t u r a l d a y l ig h t. E s t i m a t e d life of t h e b u lb is a p p r o x im a te ly 2 5 0 0 h o u rs . B u lb is o f t h e e le c tric d is c h a r g e t y p e a n d e m p lo y s m e r c u r y v a p o r to s u s t a i n t h e a r c . A la rg e a m o u n t o f f a ir ly s h o r t w a v e u l t r a v i o l e t in v is ib le r a d i a t i o n is p r o d u c e d , w h ic h is t r a n s f o r m e d i n t o lo n g e r w a v e v is ib le r a d i a t i o n b y m e a n s o f a f lu o re s c e n t p o w d e r a p p lie d t o t h e in n e r s u r f a c e o f t h e g la ss.
E a c h la m p is f u r n is h e d w ith b a l la s t, i.e. a s p e c ia l c h o k e -c o il w ith a r c s t a r t i n g d e v ic e , a s r e q u ir e d f o r o p e r a tio n o n 110 v o lts . S t a r t i n g is a c c o m p lis h e d b y m e a n s o f a p u s h - b u t t o n s w itc h w h ic h in s u r e s p o s itiv e o p e r a tio n . P r e s s u r e o n t h e r e d b u t t o n c lo se s t h e c i r c u it a n d h e a ts t h e c a th o d e a t e a c h e n d o f t h e b u lb . W h e n p r e s s u r e is r e le a s e d , t h e c i r c u it is b r o k e n a n d t h e d is c h a r g e g o es d i r e c tly t h r o u g h t h e b u lb w ith o u t a n y tim e la g . P r e s s u r e o n t h e b la c k b u t t o n b r e a k s t h e c i r c u it a n d e x tin g u is h e s t h e lig h t.
BALANCE ILLUMINATOR, Fluorescent Daylight, A.H.T.
Co. Specification. For use directly on top of an analytical balance case. Reflector insures maximum light on the front of the balance beam and pointer index. Temperature rise inside the balance case a t beam level, due to heat radiation from the bulb, is negligible.
The lamp consists of a 15-watt fluorescent bulb, 18 inches long, mounted in ventilated metal housing finished on inside with high reflecting white and on outside in dull black.
Overall dimensions, I 8J/3 inches long X 6 inches wide X 3%
inches high; mounted on felt feet. Fits a wide variety of analytical balances, i.e. those with cases 14J4 inches or more in width.
2072-F. B alance Illu m in a to r, F lu o re sc e n t D ay lig h t, A .H .T . Co. Speci
fication, as above describ ed , co m p lete w ith 1 5 -w att fluores
c e n t d a y lig h t b u lb , b a lla st, p u s h -b u tto n s ta r tin g sw itch, cord a n d plug. F o r balan ce cases M M inches or m ore in w idth. F o r 110 v o lt, 60 cycles, a.c. o n ly ... IS.75 C ode W o rd ... Aruhl 10% d isco u n t in lo ts of 6.
TITRATION LAMP, Fluorescent Daylight, A.H.T. Co.
Specification. W ith curved white reflector so designed th a t intensity of illumination over the entire surface does not vary more than 25% and no direct light reaches the eye. Housing is of heavy gauge steel finished on the outside in dull black and mounted on rubber feet.
The illuminated window, 18H inches long X 9 inches high, forms an excellent background, free from reflections from surrounding objects, for titrations, color matching, colori
metric pH determinations, turbidity rings, flocculation and precipitation tests, etc. In the latter work, a sheet of black paper is laid over the central part to obtain dark field effect.
6323. T itra tio n L am p, F lu o re s c e n t D ay lig h t, A .H .T . Co. Sp ecificatio n , as a b o v e d escribed, co m p lete w ith 15 -w att flu o rescen t d a y lig h t b u lb , b a lla st, p u s h -b u tto n s ta r tin g sw itch , tw o sh e e ts of black p a p e r w ith holders, co rd a n d plug. F o r 110 v o lts, 60 cycles.
a .c ... 16.25 C ode W o rd ... Ip krt
ARTHUR H. T H O M A S C O M PA N Y
R E T A IL — W HO LE S ALE — E X P O R T
LA BO RATO RY APPARATUS A N D REAGENTS
W E S T W ASH IN GTO N S Q U A R E, P H IL A D E L P H IA , U. S. A.
C a b le A d d re s s , “ B a la n c e ” P h ila d e lp h ia
INDUSTRIAL a n d ENGINEERING CHEMISTRY
A N A L Y T I C A L E D I T I O N
P U B L I S H E D B Y T H E A M E R IC A N C H E M I C A L S O C I E T Y • H A R R IS O N E . H O W E , E D I T O R
C olorim etric D eterm ination o f P hosphorus in Iron Ore
E. JO H N C EN TER ' AND HOBART H . WILLARD U niversity o f M ichigan, A nn A rbor, M ich.
pOUTECHNiW)
I
R O N interferes indirectly w ith th e colorimetric determ ination of phosphorus. A sample ru n b y th e regular pro
cedure b u t w ithout addition of th e final reagent is colorless to the eye, an d regardless of the percentage of iron in the sample the tran sm itta n ce a t 450 millimicrons in a Coleman spectro
photom eter is th e sam e (distilled w ater is used as a blank).
C urve 2 , Figure 1, shows th e spectral distribution of such a sample. C urve 1, Figure 1, shows th e spectral distribution of a regular sam ple containing th e yellow phosphorus complex
[(NH^jPO^.NH^VOa.ieMoOs according to Mission (/)].
4 0 0 3 0 0 COO
W /} y £ I M G 7 f t
rt/LLIfllceoNS
F i g u r e 1. T r a n s m i t t a n c e C u r v e s C olor developed
C olor undeveloped
T he proper w idth of th e m onochrom atic light band (30 millimicrons) is also indicated on this curve, which shows th a t a narrow er slit, 5 or 10 millimicrons, would not be ap
plicable in elim inating fixed iron interference, and is im
practical because of th e decreased energy o u tp u t from th e
> P re s e n t ad d ress, B a tte lle M em orial In s titu te , C olum bus, Ohio.
spectrophotom eter (less light falls on th e photoelectric cell) and th e critical wave-length setting. Figure 1 also indi
cates th a t a larger slit is out of th e question. T hus a wave length of 450 millimicrons is employed w ith a w idth of 30 millimicrons.
Although th e iron interference is constant for varying per
centages of iron when the color complax is undeveloped, a m arked deviation from th e correct phosphorus content is noted when th e color is developed and th e iron value falls below th e 50 per cent m ark. In a lean ore or rock (iron below 50 per cent) this phenom enon indicates a low value for th e phosphorus content. Figure 2 shows th e deviation in th e phosphorus value as a function of iron per cent.
F or an ordinary iron ore th e interference is negligible. If th e am ount of iron in a sample of lean ore or rock is known, th e per cent of phosphorus can be obtained from F igure 2 by adding the correction from th e plot to th e ap p aren t colori
m etric value.
T he am m onium phosphovanadom olybdate solution is a p preciably sensitive to tem perature changes, and, for th e m ost precise analysis, samples m ust be ru n a t co nstant tem pera
ture. In this work 27° C. is arb itrarily selected as a con
venient tem perature for seasonal work.
Distilled w ater does n o t change appreciably in transm ission with tem perature changes. Therefore, it can be su b stitu ted for th e theoretically correct iron blank th u s elim inating the necessity of keeping th e blank a t any definite tem perature;
moreover, distilled w ater does n o t v ary in transm ission over a period of tim e whereas a colored, highly acid iron blank m ust be constantly checked against a standard. T he use of a dis
1 7 0
* é o k
* J O
<v 4 0
$
3 0\ N .
ci .00/ .ooe .003 .004 .005 .OCX,
P f/e cf/v r f^ojp/ioeus
Fi g u r e 2 . Ir o n In t e r f e r e n c e w i t h Co l o r i m e t r i c Ph o s p h o r u s
287
288 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
CoHctNTMnoN, P e n c /n r
F i g u r e 3 . P e r C e n t T r a n s m i t t a n c e v s. P e r C e n t P h o s p h o r u s
D istilled w a ter used as a b lan k . Color co m p ared a t 27° C.
tilled w ater blank changes th e concentration vs. tran sm ittan ce curve (Figure 3).
F or increased accuracy and economy of tim e th e original colorimetric m ethod for phosphorus (S) has been slightly m odi
fied. A 1-gram sam ple is used instead of th e original 0.5 gram to allow th e determ ination of silica and m anganese on th e sam e sample.
P r o c e d u r e
Weigh out a 1-gram sample of iron ore into a 150-ml. beaker, add approximately 10 ml. of concentrated hydrochloric acid, and heat on a hot plate until the sample is in solution, adding more hydrochloric acid if necessary.
When the ore is in solution add 0.5 ml. of concentrated nitric acid, evaporate the solution to dryness, and carefully bake.
Allow the beaker to cool somewhat, add 15.0 ml. of 70 to 72 per cent perchloric acid, and fume on a hot plate until the dark brown ferric solution has changed to a light straw color. The color change requires from 3 to 6 minutes, depending on the temperature of the hot plate. Extreme care should be taken to see th at no organic m atter contacts the hot fuming perchloric acid.
Allow the sample to cool slightly, add 10.0 ml. of ammonium vanadate solution, place the sample back on the hot plate, and bring it to a boil.
Ta b l e I. De t e r m i n a t i o n o p Ph o s p h o r u s S am p le N o. V olum etric P h o sp h o ru s
C olorim etric
% %
888 GG 0 .0 5 8 0 .0 5 8
889 GG 0 .0 6 6 0.0 6 4
7106 G B 0 .0 8 2 0.0 8 1
7107 G B 0 .0 8 9 0 .0 8 8
7108 GB 0 .0 9 3 0 .0 9 2
8C6 M B 0 .1 0 4 0.1 0 4
867 M B 0 .1 0 5 0 .1 0 5
868 M B 0 .1 2 9 0 .1 2 8
869 M B 0 .1 2 8 0.1 2 7
870 M B 0 .0 8 2 0 .0 8 2
871 M B 0 .0 9 9 0.0 9 9
Remove the sample from the hot plate and wash the cover glass with a little distilled water; filter into a 100-ml. volumetric flask. Scrub the beaker and wash the contents onto a filter paper.
Wash the filter paper five times with distilled water. The in
soluble residue on the paper may be used for a silica determination.
Fill the volumetric flask to the m ark with distilled water, and mix by repeatedly inverting the stoppered flask. Measure out 50.0 ml. to use for a manganese determination if required.
To the remaining aliquot in the flask add 7.5 ml. of ammonium molybdate solution. Invert and shake the flask to mix the re
agents and dissolve the precipitate th a t first forms. Place the sample in a water bath maintained a t 27.0° C. When the sample is a t bath temperature measure the transm ittance a t 450 milli
microns in a Coleman spectrophotometer. Read the per cent of phosphorus from the concentration vs. transm ittance curve (Figure 3).
T able I shows a com parison of th e colorimetric and volu
m etric m ethods for determ ining phosphorus.
S u m m a r y
T he colorimetric determ ination of phosphorus in iron ores by th e phosphovanadom olybdate m ethod gives results in good agreem ent w ith th e usual volum etric m ethod. Iron gives a definite m easurable interference which is negligible if th e ore is above' 50 per cent iron. T em perature m ust be controlled for th e m ost accurate work.
L i t e r a t u r e C i t e d (1) M ission, G., Chem.-Ztg., 32, 633 (1908).
(2) W illard, H . H ., and C enter, E . J., I n d . E n g . Chem., A n a l . E d ..
13, 81 (1941).
A F ilterin g D evice for V iscosity T ubes
STA N FO R D J . H E T Z E L S u n Oil C o m p a n y , N orw ood, P c n n a .
C
O N S ID E R A B L E difficulty is often encountered in preparing an uncontam inated sam ple of oil or o ther liquid for a viscosity determ ination. A. S. T . M . D esignation D-445-39T requires th a t th e sam ple be filtered th rough sin
tered glass or a fine wire screen into a sm all beaker or bottle.
I t is som ew hat difficult to keep all th e ap p a ra tu s clean and free from solid particles or lin t and, unless g rea t care is exer
cised, th e sam ple m ay pick u p lin t from th e air before being transferred to th e viscom eter pipet.
The filtering device illustrated is a much more convenient and rapid means for ensuring an uncontaminated sample for viscosity measurement. I t consists of a small interchangeable filtering cap made by sealing a sintered-glass disk 20 mm. in diam eter and 2 mm. thick in a glass tube fitted with a standard f Vis female joint. A male joint is ground on the end of th e capillary arm of the viscometer. W ith the cap in place the pipet is inverted and immersed in the beaker or wide-mouthed bottle containing the sample, and filled by suction in the usual manner.
Two porosities of sintered-glass disks, medium or coarse, de
pending on the viscosity of the sample, may be used. The filter
ing cap holds about 0 to 7 cc. of sample.
- Cleaning is accomplished by drawing petroleum ether or ben
zene through the cap in order to retain any foreign particles on the outside and drying in a stream of air or in an oven.
C olorim etric D eterm ination o f N ickel with A m m onia
A Spectropliotom etric Study
J . P. M EH LIG , O regon S la te College, Corvallis, Ore.
A
LTH O U G H it has long been known th a t nickelous salts in l the presence of excess am monia give a blue to violet colored complex, un til recently little has been done tow ard the developm ent of a colorimetric m ethod for the determ ination of nickel based upon this reaction. Two methods have been proposed for its determ ination in steel.Fieber (4) determined it in the filtrate after filtration of the iron precipitate produced by ammonium hydroxide, while Ayres and Smith (/) separated the nickel as the dimethylglyoxime salt, decomposed tne precipitate with nitric acid, and determined the nickel in the resulting solution. They have stated th at as little
¡is 5 p. p. m. of nickel can be detected with certainty when the Yoe (16) photoelectric colorimeter is used. The region of highest sensitivity, however, lies between 500 and 1500 p. p. m. The error may am ount to as much as about 5 per cent.
T he purpose of th e work described in this paper was to make a critical stu d y of this m ethod by means of the photo
electric recording spectrophotom eter (10), with particular atten tio n to th e effect of diverse ions upon the color system . Similar studies of other colorimetric m ethods have recently been m ade w ith this instrum ent (2, 3, 5, 6 ,8 ,9 ,1 1 ,1 2 , 18).
A p p a r a t u s a n d S o l u t i o n s
All spectrophotometric measurements in the present work were made a t Purdue University with the self-recording instrument used by the writer in previous investigations (8, 9).
F i g u r e 1. T r a n s m i t t a n c y C u r v e s f o r N i c k e l - A m m o n i a 100, 200, 300, 500, 1000, a n d 1500 p. p. m. of nickel in 1.5 M am m onium
hydroxide. 4.976-cm . ceil
A standard stock solution of nickelous nitrate, each milliliter of which contained 10 mg. of nickel, was made by dissolving 20.0133 grams of metallic nickel, of 99.93 per cent purity, in dilute nitric acid and accurately diluting with redistilled water to 2 liters.
Ammonium hydroxide solutions of various concentrations, such as 0.5, 1.5, 3, 4.5, and 6 M , were made by suitable dilution of the concentrated solution of specific gravity 0.90.
Standard solutions of the diverse ions were prepared from the chloride, nitrate, or sulfate salts of the cations and from the sodium, potassium, or ammonium salts of the anions. Redis
tilled water was used in all cases. Each milliliter contained 10 mg. of the ion in question.
To produce the color system 5 ml. of the standard stock solu
tion of nickel in a 100-ml. volumetric flask were just neutralized with 15 M ammonium hydroxide, diluted to the mark with 1.5 M ammonium hydroxide (1), and thoroughly shaken.
The spectral transmission curves were determined for a solution thickness of 4.976 cm. and a spectral band width of 10 m/x.
Compensation for the absorption of light by the glass cell and solvent was obtained by placing in the rear beam of light a similar cell filled with 1.5 M ammonium hydroxide.
T h a t th e color reaction m ay be reproduced to a high degree of precision is shown b y th e fact th a t thirty-one solutions of th e nickel-ammonia complex, each containing 500 p. p. m . of nickel and prepared by th e above procedure, gave trans- m ittaneies a t 582 mju (the peak of the absorption band), th e average deviation of which from th e m ean was 0.15 per cent.
T he tran sm ittan cy curves for varying am ounts of nickel are shown in Figure 1.
C o n f o r m i t y t o B e e r ’s L a w
Proof th a t B eer’s law is followed by th e color system is shown by the straig h t line which resulted when the logarithm s of th e observed transm ittancies a t 582 m/i for six solutions, containing from 100 to 1500 p. p. m. of nickel, were plotted against th e respective concentrations. Ayres and Sm ith (1) using th e Yoe colorimeter (16) reported th a t th e system fol
lows Beer’s law up to 600 p. p. m. of nickel.
E f f e c t o f A m m o n i u m H y d r o x i d e
Yoe and Crum pler (16) have pointed o u t th a t am m onia solutions show an appreciable absorption of light in the;
visual region. I t has been shown (9, 15) th a t th e concentra
tion of am monium hydroxide has a pronounced effect upon th e color of th e copper-ammonia system . A sim ilar result should be expected for th e nickel-am monia system , which to the eye shows a change in hue from blue to violet as the con
centration of am m onia increases.
The spectral transm ission curves produced by a series o f five solutions, each containing 500 p. p. m. of nickel, b u t m ade by use of 0.5, 1.5, 3, 4.5, and 6 M am m onium hydroxide, were compared. In each case the corresponding concentration of ammonium hydroxide was used in th e rear cell. T he curves (Figure 2) show th a t th e hue gradually changes as th e concen
tration of the am monium hydroxide varies. B oth th e maxi
m um absorption and th e w ave length of maximum absorption decrease as th e concentration increases. Therefore, it is necessary th a t th e concentration chosen for th e determ ination be used throughout in m aking all th e unknown as well as standard solutions which are to be used for comparison. In.
289
WAVC L E N G T H
Fi g u r e 2 . Ef f e c t o f Co n c e n t r a t i o n o f Am m o n i u m Hy d r o x id e
500 p. p. in. >>f nicki*l in 0.5, 1.5, 3, a n d 6 M a m m o n iu m hydroxide.
4.976-cm . celL
th e present w ork th e 1.5 M solution used by Ayres and Sm ith (1) was selected. Because of th e high concentration of am m onia, no a tte m p t w as m ade to determ ine p H values.
S t a b i l i t y o f t h e C o lo r
Six solutions, containing 100, 200, 300, 500, 1000, an d 1500 p. p. m. of nickel, respectively, in 1.5 M am m onium hydroxide, were stored in glass-stoppered Pyrex b ottles an d allowed to sta n d in diffuse light. Curves m ade a t intervals for these solutions gave no evidence of fading or o ther change in color over a period of 4 weeks. T im e was n o t available for a longer testing period. A pparently th e color is stable indefi
nitely. Such m arked sta b ility m akes possible th e use of a series of perm anent standards, which m ust, however, be kep t tig h tly stoppered to p revent loss of am m onia. A ny action of th e am m onia on th e glass to produce tu rb id ity is reduced to a m inim um b y using Pyrex containers.
A yres and S m ith (1) found no change in th e color a fte r 150 hours, b u t did n o t m ake te sts over a longer tim e.
E f f e c t o f A n i o n s
In th e ion interference studies th e curve produced by th e sta n d ard solution containing 500 p. p. m . of nickel in 1.5 M am m onium hydroxide w as com pared w ith th e curve produced b y a sim ilar nickel solution containing in addition a known w eight of th e diverse ion. F rom th e transm ittancies a t 582 m/i of th e stan d ard solution and of each of th e o ther solutions a n d from th e known nickel concentration of th e stan d ard solution, th e ap p a ren t concentration of nickel in each of th e solutions containing diverse ions was calculated b y th e aid of a special color slide rule. T he difference betw een this value a n d the actual concentration m ultiplied b y 100 an d divided by th e actual concentration gave th e percentage error. T he calculation is based upon the form ula
CJ Tt = T *
w here T i represents th e transm ittancy, expressed as a deci
m al, for th e solution of concentration Ci an d T 2 th e tra n s
m itta n c y for th e solution of concentration Cj. I n accordance w ith th e practice followed in three form er studies b y th e w riter (8, 9) an d b y o ther w orkers a t P u rd u e U niversity {2, 3, 5, 6, 11, 12, IS) a 2 p er cent error was set as th e m axim um allow able for negligible interference. A lthough visual m ethods o f color com parison often hav e a precision of n o t less th a n
5 per cent, it was th o u g h t advisable to set a lower figure to provide for other possible factprs.
W hen there is a change in hue th e curve does n o t have the same general shape as th e sta n d ard curve and th e p o in t of m axim um absorption occurs a t a different w ave length.
T he interfering anions m ay be divided into four general classes: those, such as cyanide, which form complexes w ith th e nickel ion w ith o u t a change in hue; those, such as citrate, pyrophosphate, an d salicylate, which form complexes w ith a change in hue; those, such as dichrom ate, which cause a change in hue because of th eir own color; and those, such as chlorostannate, chlorostannite, silicate, tu n g state, and van a
date, which cause tu rb id ity because of th eir own hydrolysis or th e precipitation of nickel salts.
In Figure 3, curves 2 and 3 show th e effects of 500 and 100 p. p. m. of chrom ium as dichrom ate ion, curve 4 th e effect of 300 p. p. m. of cyanide ion, and curve 5 th e effect of 500 p. p. m.
of oxalate ion.
T he effects of th e common anions and their approxim ate lim iting concentrations are listed in T able I.
E f f e c t o f C a t i o n s
C obaltous and cupric ions are the only common cations which really interfere. T h ey form soluble, colored am m onia complexes, causing a decided change in hue. In Figure 4, curves 2 and 3 show th e effects of 50 and 25 p. p. m. of cobal
tous ion and curves 4 an d 5 th e effects of 50 an d 25 p. p. m . of cupric ion. Silver, cadmium , and zinc ions form colorless am m onia complexes which do n o t interfere. Aluminum , antim onous, barium , beryllium , bism uth, chromic, ferric, ferrous, lead, m agnesium (in th e absence of am m onium chloride), m anganous, m ercuric, m ercurous, strontium , thorium , uranyl, and zirconium ions precip itate as hydroxides or basic salts in th e alkaline solution. T hese precip itates can
Ta b l e I . Ef f e c t o f Di v e r s e An i o n s (50 m g. of nickel in 100 m l. of solution)
Ion C o n c e n tra tio n
A p p a re n t C h an g e in N ick el C o n c e n tra tio n
A pp ro x im ate L im iting C o n ce n tratio n
P . p. m. % P . p. m.
A c eta te 500 N egligible
A rsen ate 500 (As) N egligible
A rsenite 500 (As) N egligible
B en zo ate 500 N egligible
B o ra te 500 (BiOj) N egligible
B ro m id e 500 N egligible
C a rb o n a te 500 C h an g e in hue
100 N egligible 150
C h lo ra te 500 N egligible
C hloride 500 N egligible
C h lo ro sta n n a te 500 (Sn) P re c ip ita te s
300 (Sn) + 1 .9 300
C h lo ro sta n n ite 100 (Sn) P re c ip ita te s 0
C itra te 100 C h an g e in h ue 0
C y an id e 300 - 1 7 . 8
100 - 0 .4 0
D ich ro m ate 100 (C r) C h an g e in h ue 0
F luoride 500 N egligible
...
F o rm a te 500 N egligible
Io d id e 500 N egligible
M o ly b d ate 500 (M o) N egligible
N itra te 500 N egligible
N itrite 500 N egligible
O rth o p h o sp h a te 500 (P 20*) N egligible
O x alate 500 C h an g e in h ue
100 + 7 .7 0
P e rc h lo ra te 500 N egligible
P y ro p h o sp h a te 100 - 3 . 0 •¿Ö
S alicy late 500 C h an g e in h u e
100 + 1 .6 100
Silicate 100 (SiOi) P re c ip ita te s 0
Su lfate 500 N egligible
S ulfite 500 N egligible
¿66
T a r t r a te 500 + 2 .0
T h io c y a n a te 500 N egligible
T h io su lfate 500 T u rb id ity
200 + 2 . 2 150
T u n g s ta te 500 T u r b id ity
300100 + 3 . 0
N egligible 150
V a n ad a te 20 (V) P re c ip ita te s 0
April 15, 1942 A N A L Y T I C A L E D I T I O N
Ta b l e I I . Ef f e c t o f Di v e r s e Ca t i o n s (50 mg. of nickel in 100 m l. of solution)
A p p a re n t C hange
Ion C on cen tratio n in N ickel
C o n ce n tratio n P . p. in.
A m m onium 500 N egligible
C adm ium 500 Negligible
Calcium 500 Negligible
C obaltous 25 C hange in hue
C upric
Lithium 25 C hange in hue
500 Negligible
M agnesium 200 Negligible«1
Potassium 500 N egligible
Silver 500 N egligible
Sodium 500 N egligible
Zinc 500 Negligible
a If am m onium chloride is presen t.
A pp ro x im ate L im itin g C o n ce n tratio n
P . p. m.
precipitate produced by am m onium hydroxide in th e absence of ta rtra te be filtered and the nickel determ ined in th e filtrate w ithout resorting to th e dimethylglyoxime separation.
T he concentration of th e am m onium hydroxide used for dilution m ust be carefully controlled because of the a b ility of the am monia solution to absorb light. Since th e hue varies with th e concentration, the same concentration m u st be used for the standards as for the unknown solutions. A 1.5 M solution is recommended.
T he color system follows Beer’s law.
The color is stable in diffuse light for a t least 4 weeks and undoubtedly for a m uch longer time. T he use of a series of perm anent standards is therefore possible.
The color reaction m ay be reproduced to a high degree of precision.
A study of th e effect of sixty common ions shows th a t only a few, especially cobaltous, cupric, cyanide, and dichrom ate, seriously interfere w ith the color and th a t m any of th e cations
W A V E L E N G T H
Fi g u r e 3 . Ef f e c t o f An i o n s
500 p. p. m. of nickel w ith diverse anion in 1.5 M am m onium hydroxide.
4.976-cm . cell
be removed b y filtration, as was done by Fieber (4), b u t Ayres and Sm ith (1) chose instead to separate the nickel by precipi
ta tin g it from slightly am moniacal solution in the presence of ta rtra te w ith dimethylglyoxime. This separation is satis
factory for steel, b u t if th e m ethod were to be applied to general testing w here an y of th e ions listed above m ight be present, some of them would undoubtedly be precipitated in th e alkaline solution. T he w riter recommends for miscel
laneous m aterials relatively low in iron, in the absence of co
b alt and copper, a procedure sim ilar to th e one used in the am m onia m ethod for copper (7, 14), wherein the precipitate produced b y am m onium hydroxide is filtered and the deter
m ination is m ade on th e filtrate.
A lthough am m onium chloride has been shown (9,15) to in
tensify th e color of th e copper-ammonia system, 1003 p. p. m.
of am m onium ion as chloride have no effect upon the color of the nickel-am monia system.
I n T able I I are listed th e effects and approxim ate lim iting concentrations of the common cations which do not cause precipitation.
S u m m a r y
A spectrophotom etric stu d y shows th a t the ammonia m ethod for th e colorimetric determ ination of nickel is satis- factory although n o t highly sensitive. The region of highest sensitivity lies between 500 and 1500 p. p. m. of nickel. While th e precision is n o t high, th e average of several determ inations agrees well w ith th e results obtained b y the gravim etric dimethylglyoxime m ethod.
T he Ayres an d Sm ith m ethod need n o t be restricted to the determ ination of nickel in steel. However, for miscellaneous m aterials relatively low in iron it is recommended th a t any
6 9 0 TOO WAVE LEN G TH
Fi g u r e 4 . Ef f e c t o f Ca t i o n s
500 p. p . m . of nickel w ith diverse catio n in 1 .5 'Af a m m o n iu m h y d ro x id e.
4.976-cm . cell
292 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y cause precipitation or turb id ity , b u t in th e course of the
determ ination this la tte r group would be removed.
A c k n o w l e d g m e n t s
T he w riter expresses his sincere appreciation to M . G.
M ellon of P urdue U niversity, in whose laboratory this in
vestigation was conducted, and th an k s him for th e privilege of using th e P urdue spectrophotom eter. T hanks are also given to R . E. K itson for his aid in adjusting th e spectrophotom eter.
L i t e r a t u r e C i t e d
(1) A y re s , G. H ., and Sm ith, F ., I n d . E n g . C iie m ., A n a i ,. E d ., 11, 365 (1939).
(2) B yers, D . H ., and M ellon, M . G., Ibid., 11, 302 (1939).
(3) D rag t, G., and M ellon, M . G., Ibid., 10, 256 (1938).
(4) Fieber, R ., Chem.-Ztg., 24, 393 (1900); J . Soc. Chem. In d ., 19, 563 (1900).
(5) Fortune, W . B., and M ellon, M . G., I n d . E n o . Ch em., A n a l . E d ., 10, 60 (1938).
(6) Howe, D . E ., and M ellon, M . G „ Ib id ., 12, 448 (1940).
(7) Mehlig, J. P., Ibid., 7, 387 (1935).
(8) Ibid., 10, 136 (1938); 11,274 (1939).
(9) Ibid , 13, 533 (1941).
(10) M ichaelson, J . L., and Liebhafsky, H . A., Gen. Elec. Rev., 39, 445 (1936).
(11) Sw ank, H . W ., and M ellon, M . G., I n d . E n g . Ch em., A n a l . E d ., 9 ,4 0 6 (1 9 3 7 ); 1 0 ,7 (1 9 3 8 ).
(12) W oods, J . T ., an d M ellon, M . G., Ibid., 13, 551 (1941).
(13) W right, E. R „ and MeUon, M . G., Ibid., 9, 251, 375 (1937).
(14) Yoe, J . H ., “ P hotom etric Chemical Analysis” , Vol. I, p. 176, N ew Y ork, Jo h n W iley & Sons, 1928.
(15) Yoe, J. H „ and B arto n , C. J., I n d . E n o . Chem ., A n a l . E d . , 12, 456 (1940).
(16) Yoe, J. H „ and C rum pler, T . B „ Ibid., 7, 281 (1935).
A nalysis o f C ellulose D erivatives
Analysis o f C ellulose M ixed Esters by the P artition M ethod
CARL J . M ALM , GALE F . NADEAU, AND LEO B. GENUNG E a s tm a n K odak C o m p an y , R o c h e ste r, N . Y.
Several m e th o d s have been p roposed fo r th e d e te rm in a tio n o f th e c o m b in ed acid s in m ixed e ste rs o f cellulose, m o s t o f th e m b ased o n som e ph y sical p ro p e rty o f th e acid s. T h e d iffe ren tia l
• p a r titio n (or d is trib u tio n ) o f th e acid s betw een im m isc ib le solvents h a s proved to b e a sa tisfa c to ry a n d p ra c tic a l m e a n s for d e te rm in in g th e co m p o si
tio n o f m ix tu re s o f acid s. T h is p rin c ip le w as u tiliz e d by B e h re n s a n d th e m a n ip u la tio n w as im proved a n d sim plified by W e rk m a n . I t h a s now b e e n ap p lied to cellulose m ixed e s te r an a ly sis, a n d b u ty l a c e ta te h a s b ee n fo u n d to be a p a r tic u la rly s u ita b le e x tra c ta n t fo r m ix tu re s o f ac etic, p ro p io n ic , a n d b u ty ric acids.
T h e an a ly sis o f a cellulose m ixed e s te r by th e
V
ARIO US mixed esters of cellulose and p articularly the cellulose ac etate propionates and a c etate b u ty rates have proved successful com mercially because of th e ability to vary their properties to m eet different requirem ents b y v ary ing their compositions. T h e analysis of these esters presents th e usual difficulties encountered in analyzing neighboring mem bers of a homologous series of organic com pounds.Since there is little difference in chemical properties between such members, it is necessary to m ake use of some physical pro p erty as th e basis for an analy tical m ethod.
The older method for analyzing mixtures of such acids was th a t of Duclaux (6), with various modifications and improve
ments (7, 14, 28, 32), which is based on differences in the rates of distillation of the various acids. Behrens (2) proposed the use of the differential distribution (or partition) of the acids between immiscible solvents such as diethyl ether and water.
This method has many advantages over th a t of Duclaux, the most im portant of which is th a t a greater numerical spread in values m ay be obtained. Behrens titrated the acid present in each phase and calculated his results algebraically using simul
taneous equations. He showed th a t mixtures of as many as five acids could be analyzed with reasonable accuracy by measur
ing partitions under several different sets of conditions. The acids studied were acetic, propionic, butyric, valeric, caproic, succinic, lactic, glycolic, malic, citric, and tartaric.
Werkman successfully applied this principle to two-component
p a r titio n m e th o d involves th e follow ing ste p s:
d e te rm in a tio n o f to ta l c o m b in ed acids by som e s u ita b le m e th o d , sa p o n ifica tio n a n d isolatiorf o f th e se co m b in e d acids, d e te r m in a tio n o f th e p a r t i tio n coefficients b etw e en b u ty l a c e ta te a n d w ate r o f th e acid m ix tu re a n d also s e p a ra te m e a s u r e m e n t o f th e p a r titio n coefficients o f e a c h acid p re se n t, c a lc u la tio n o f th e m o la r ra tio s o f th e ac id s using s im u lta n e o u s e q u a tio n s , a n d c a lc u la tio n o f th e w eig h t p e r c e n t o f th e acid s, o r co m b in e d acyl, fro m th e m o la r ra tio s a n d th e to ta l acid c o n te n t o f th e e ste r. P re cisio n , a c cu rac y , a n d lim its o f a p p lic a b ility a re given. M o d ificatio n s o f th e p ro c e d u re a re d escrib ed fo r c e r ta in h ig h e r acyl e ste rs a n d for n o n v o la tile acid esters.
mixtures using isopropyl ether (29), diethyl ether (30), and iso
amyl ether (31). Calculations were made by graphical methods.
Osburn and Werkman (18) extended the procedure to mixtures of acetic, propionic, and butyric acids and developed nomo
grams to simplify the calculation. L ater (19) they modified the procedure to include formic acid and to indicate the presence of other acids such as lactic and pyruvic. Fuchs (8) lias sys
tematically studied the indirect methods of analysis, including application of the partition method to mixtures of the lower aliphatic acids.
Yaekel, Staud, and Gray (34) applied the procedure of Werk
man to cellulose esters by saponifying the esters by the modified Eberstadt method (16), removing the alcohol by evaporation, acidifying with phosphoric acid, and steam-distilling. The acid distillates were extracted with diethyl ether. Steam-distillation of propionic and butyric acids is not very satisfactory from an analytical standpoint, so Yackel, Kenyon, and Gray (33) modi
fied this procedure by saponifying, removing the alcohol by evaporation, diluting, and exactly neutralizing the alkali with standard hydrochloric acid. The regenerated cellulose was then filtered off, and the filtrate was extracted with diethyl ether by th e method of Werkman (30). The sodium chloride present was shown to have a negligible effect on the distribution coeffi
cients of the acids.
M alm and Nadeau (15) improved these procedures by saponi
fying the cellulose ester without the use of alcohol and used vacuum-distillation for separating the organic acids from the regenerated cellulose. Normal propj'l and butyl acetates were found to have m any advantages over the ethers as extracting
