Industrial and Engineering Chemistry : analytical edition, Vol. 6, No. 3

A

E

V

. 6, N o . 3

M a y

15, 1934

I n d u s t r i a l

AN D E N G IN E E R IN G

C h e m i s t r y

VOL. 26, C O N SECU TIV E NO. 17

P u b l i s h e d b y t h e A m e r i c a n C h e m i c a l S o c i e t y H a r r i s O n E . H o w e , E d i t o r

Pu b l i c a t i o n Of f i c e: E a sto n , Pa.

Ed i t o r i a l Of f i c e:

Room 706, Mills B uilding, W ashington, D . C.

Te l e p h o n e: N atio n al 0848 Ca b l e: Jiechem (W ashington)

Ad v e r t i s i n g De p a r t m e n t: 332 W est 42nd St.,

New Y ork, N. Y.

Te l e p h o n e: B ry a n t 9-4430

C O N T E N T S

14,900 Copies of This Issue Printed Q uantitative Spectroscopic Analysis of S o lu tio n s ...

... Wallace R. Brode and James G. Sleed 157 Covering C apacity (on W ater) of Aluminum Bronze

Pow der . . Ju n iu s D. Edwards and Ralph D. Mason 159 Analysis of M ixtures of Oxalic and Citric Acids by T itra­

tion w ith Ceric Sulfate ... ./. A . Wilkinson, I . R . Sipherd, E . I . Fulmer, and L. M . Christensen 161 Choice of C atalysts for the H ydrogen E le c tr o d e ...

... Arthur E . Lorch 164 A M ethod for M easuring th e Dew P oint of N atural Gases

... A . Michels and G. W . Nederbragl 165 A Photronic Colorimeter and Its Application to the D e­

term ination of F lu o r i d e ...L . V. Wilcox 167 Use of Trichlorobenzene in Analysis of G raphite Greases

... Frank M . BiJJen 169 D eterm ination of Peroxidase A ctivity . . Dean A . Pack 170 A Stirrer for Solvent E xtraction . . John A . Patterson, Jr. 171 M icroanalysis of Gaseous M ixtures by Pressure-Tempera-

ture Curves . . J . J . S . Sebastian and II. C. Howard 172 T u rb id ity in Sugar Products. I I ...

. . . F. W . Zerban, Louis Saltier, and Irving Lorge 178 D eterm ination of Viscosity of D ilute Solutions of Cassava

Flour and O ther S t a r c h e s ...Gordon G. Pierson 183 D eterm ination of Dielectric C onstants by M eans of Radio

...M . M . Otto and II. H. Wenzhe 187 E stim ation of Small A mounts of B ism uth, A ntim ony, Tin,

and M olybdenum in C o p p e r ...Bartholow Park 189 D eterm ination of th e Acids of P la n t Tissue. I l l . . . .

. . . . George W . Pucher, Hubert Bradford Vickery, and Charles S . Leavenworth 190 Double-Acid M ethod of O ptical Analysis of B eet Products

... S . J . Osborn and J . II. Zisch 193

D eterm ination of M inute Q uantities of Sulfide Sulfur . . . ... C. E . Lachele 200 A M icro H ot-P late for Protein H ydrolysis . A . R. Patton 201 R apid Centrifugal E stim ation of Small A m ounts of Sodium

...Earle R . Caley, C. T. Brown, and II. P. Price 202 D eterm ination of Pentosans in Vegetable M aterials Con­

taining Tannins ... A . P. Sakostschikaff, W . T. Iwanowa, and A . M . Kurennowa 205 Filtering F ru it Juices and P la n t E x t r a c t s ...

... J . A lfred Hall and Willard E . Baier 208 D eterm ination of Small Q uantities of Sodium C arbonate

... John E. S . H an 209 Q uantitative D eterm ination of Coumarin in P la n t M aterial

... Ira J . Duncan and R . B. Dustman 210 D eterm ination of Bromide in the Presence of Large Excess

of Chloride . . . . Roy F. Newton and Edith R. Newton 213 Im proved A pparatus for Q uantitative E stim ation of

Helium in G a s e s ...

. Frank E . E . Germann, K . A . Gagos, and C. A . Neilson 215 C ontinuous D eterm ination of C arbonate-C austic R atio in a

Carbon Dioxide Absorption System . Allen S . Sm ith 217 D eterm ination of Inorganic Salts in Sulfonated Oils . . .

... Ralph Hart 220 D eterm ination of Alpha-Cellulose . C. Kilbourne B um p 223 D eterm ination of Sulfur in Benzene or G a s o lin e ...

... II. 0 . Ervin 225 Im proved Analyzer for Carbon Monoxide in A i r ...

...II. W . Frevert and E . II. Francis 226 M ixed Perchloric and Sulfuric Acids. I ...

... G. Frederick Sm ilh 229

Subscription to nonm em bers, In d d s t b i a la n d En g i n e e r i n g Ch e m i s t b t, $7.50 per y ear. Foreign postage 82.10, except to countries accep tin g m ail a t Am erican dom estic rates. T o C an a d a , 70 cents. An a l t t i c a l Ed i t i o nonly, *2.00 p er year, single copies 75 cents, to m em bers 60 cents. Foreign postage, 30 cents; C an ad a, 10 cents. Ne w s Ed i t i o n only, S1.50 per year. Foreign postage, 60 cen ts; C an a d a , 20 cents, Subscriptions, changes of address, and claim s for lost copies should be referred to C harles L. Parsons, S ecretary, M ills B uilding, W ashington, D. C . T he Council has v o ted t h a t no claim s »-ill be allowed for copies of jo u rn als lost in th e mails, unless such claim s are received w ithin 60 days of th e d a te of issue, and no claim s will be allow ed fo r issues lost as a resu lt of insufficient notice of change of address. (T en d ay s' advance notice required.) "M issing from files can n o t be accepted as th e reason for honoring a claim , if change of address im plies a change of position, please in d icate its natu re.

T he Am erica n Chem ical Societyalso publishes the Journal o f the American Chemical Society and Chemical Abstracts.

4 A N A L Y T I C A L E D I T I O N Vol. 6, No. 3

The new Sargent

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Published by th e A m erican Chem ical Society, P u blication Office, 20th & N o rth a m p to n Sts., E asto n , Pa.

E n tered as second-class m a tte r a t the Post-Office a t E asto n , Pa., un d er th e a c t of M arch 3, 1879, as 42 tim es a year. In d u stria l E d itio n m o n th ly on the 1st; News E dition on th e 10th an d 2 0 th ; A nalytical E d itio n bim o n th ly on the 15th. A cceptance for mailing: a t special

r a te of postage provided for in Section 1103, A ct of O ctober 3. 1917, authorized Ju ly 13, 191S.

May 15, 1934 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 5

V I N E L A N D , N E W J E R S E Y .

N E W Y O R K • P H ILA D E LP H IA • B O STO N . C H IC A G O ■ D ETR O IT

K I M B L E G L A S S C O M P A N Y

The nam e " E X A X " on a burette is your assu ran ce of quality a n d accuracy. This Kim ble tra d e -m ark — a p p e a r ­ ing on Kim ble G ra d u a te d G la s s w a r e — stam ps the burette as com m ercially exact a n d d e p e n d a b le for all industrial scientific control a n d analyses.

O U T S T A N D IN G F E A T U R E S

1. M a d e from a u to m a tic -m a c h in e -m a d e tu b in g o f v e ry uniform bore.

2. S tra ig h t, thick -w alle d , a n d free from bliste rs, ston es a n d striae.

3. R ete m p ere d (strain-free) in s p e c ia l lehr o r oven.

4. C a r e fu lly c a lib r a t e d a t 5 p oints a t 20° C. Lined a n d n u m b e re d b y a utom a tic m achin es.

5. A il lines a n d n um b e rs d e e p ly a c id -e tc h e d . Filled with d u r a b le b lu e g la s s en am el, fused-in.

6. M a in d iv isio n lines c o m p le te ly en circle tube.

7. S to p c o c k b a rre ls se a le d d irectly to burette tu b e s fo r in c re a se d strength.

8. D e liv e ry stem s c a n n o t tra p air. Low e r end o f stem s d ra w n to g r a d u a l tap er. T ip o p e n in g s g a u g e d to d e liv e r liq u id accu rate ly.

9. R u b b e r w a s h e r o n e n d o f sto p c o c k p lu g p re ven ts slip p in g , lo ss a n d b r e a k a g e .

10. S to p c o c k s a c c u ra te ly g r o u n d a n d tested a g a i n s t v a c u u m o f 1 5 "

o f mercury.

11. Every burette is retested to the se to le ra n c e s: —

10 m l ± 0 .0 4 ml

25 m l 0.06 ml

50 m l 0.10 ml

100 ml 0.20 ml

E x a x Burettes— like e ve ry other piece of Kim ble L a b o ra ­ tory G la ssw a re — a re fully gu a ra n te e d b y Kim ble for perform ance a n d w orkm anship. Sto cke d b y le a d in g Laboratory S u p p ly H ou ses throughout the United States and C a n a d a .

6 A N A L Y T I C A L E D I T I O N Vol. 6, No. 3

W I L E Y

L A B O R A T O R Y M I L L

F o r th e p r e p a r a t io n , w i t h o u t lo s s o f m o i s ­ t u r e f r o m h e a tin g , o f c e r t a in c o m m e r c ia l

m a t e r ia ls fo r la b o r a t o r y a n a ly s is

O

O p t ic a l instrum ents a re r a p id ly w in n in g a p la c e in the ch e m ic a l la b o r a to rie s . . . not n e c e ssa rily fo r re se a rc h w o rk . . . but a s a c c u ra te "tim e -sa v e rs” in r e g u la r routine w ork. Lo ok fo r the n am e "S p e n c e r “ w hen b u y in g o p tic a l instrum ents— it is y o u r g u a r ­ a n te e o f p re cise optics, corre ct d e s ig n a n d faith fu l p e rfo rm a n c e .

W r it e t o d a y fo r c o m p le te d e sc rip tio n a n d p ric e s o f this S p e n c e r A b b e Refractom eter.

L A B O R A T O R Y M IL L , W ile y . While originally designed for grinding all kinds of fertilizer m aterials, such as tan k ag e, anim al hair, fur, hoofs, horns, etc., i t is now satisfactorily used for m an y o th e r m aterials, p artic u la rly straw , tobacco stalk s, licorice roots, grass, cotto n seed, cotto n seed cake, co tto n seed meal, w heat, corn, oats, corn stalk s, chicken feathers, B akelite, leath er, cra b shells, dried fish scales a n d for shredding a g ar and gelatine for m aking c u ltu re m edia.

G as chem ists are using th is M ill fo r grinding shavings coated w ith a m ixture of iron oxide, ferrous sulphide and free su lp h u r as ta k e n from the purification u n it which rem oves IliS from coke oven a n d w ater gas.

F o u r knives on a revolving s h aft w ork w ith a shearing action against six which are s e t in th e fram e. T h e screen is dovetailed in to th is fram e so t h a t none of th e m aterial comes o u t of th e grinding ch am b er until it is fine enough to pass th ro u g h th e m esh. T h ree sieves w ith screen of l/ j m m , 1 m m and 2 m m mesh, respectively, are furnished w ith each mill. A hinged fro n t perm its easy cleaning.

T h e mill is 21 inches high an d occupies a floor space a b o u t 14 X 20 inches. G rinding cham ber is 8 inches inside d iam eter, w ith knives 3 inches wide. D raw er for ground sam ple is 7 X 3 X 2 1/« inches and holds 24 oz. liquid m easure. M ill should be o p erated a t from 400 to 8 00 r.p.m . and requires from V* to 1 h.p. Pulleys are 6 inches in d iam eter X 2*/t inches face. K nives should be ru n in counter-clock­

wise direction. A pproxim ate shipping w eight 210 lbs.

See Sam uel W . W iley, Industrial and Engineering C hemistry, March, 1925, p. 304 a n d The Am erican Fertilizer, February 7, 1925; K . M ai- wald, Die Landwirtschafllichen Versuchs-Stationen des Deulschen Reiches, 1928, p. 15; I. D. C larke and R W. F rey , The Journal o f the Am erican Leather Chemists Association, Vol. X X I I I , No. 9 (September, 1928), p. 412; and C arl R . B lom stedt, Paper Trade Journal, Vol. X C II, No. 18 {Apr. 30, 1931), p. 43.

4275. L a b o r a to r y M ill, W ile y , as above described, w ith th re e sieves.

W ith tig h t and loose pulleys for belt drive, b u t w ith o u t m o to r... 165.00 Code W o rd ... E lnfc

For above M ill u i t h d ir e c tly c o n n e c te d e le c tric m o to r , a n d f o r a s m a lle r m o d e l f o r v ery s m a ll q u a n titie s o f o rg a n ic m a te r ia l f o r m ic r o -a n a ly sis, see p p . 277-278

o f o u r c u r r e n t ca ta lo g u e .

^ k e S p e n c e r G ^ b b e

R E F R A C T O M E T E R

4275

A R T H U R H. T H O M A S C O .

R E T A IL - W H O L E S A L E - E X P O R T

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May 15, 193 t 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 7

In The Bell Telephone Lab ’y

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T h eir eq u ip m e n t is ob viou sly th e fin est th a t m on ey can b u y . It in clu d es m a n y H oskin s F urnaces th a t cost relatively little , b u t fill a sig n ifica n t p lace in th e esta b lish m en t o f fa ct. And on th is work, th e fu rn aces h ave proved th eir w orth, as th ey do in laboratories th r u o u t in d u stry . T h e featu res b est liked by ch em ists are th e fine durability o f th e C hrom el elem en ts and th eir ease o f renew al.

T h e im m a c u la te clea n lin ess o f th e fu rn ace atm osp h ere an d th e n ic ety o f tem p era tu re con trol m e e t th e req u isites o f all good ch em ists.

We in v ite y ou to sen d you r in q u iry to your laboratory dealer. And m ay b e y o u ’d lik e to w rite to u s for a h a n d y little gad get, called a

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8 A N A L Y T I C A L E D I T I O N Vol. 6, No. 3

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W hen equipped with the reinforced all steel guard, th e M u ltisp eed A tta ch m en t may be added to the Size 2 to a tta in a speed of approxi­

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T.

Y ou can use w a re t h a t is m ore re sis ta n t to h e a t and m e ch a n ica l sh o c k .

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ance to h e a t a n d te m p e ra tu re changes. A nd in d ire c tly th is p ro p e rty creates g re a te r m e c h a n ic a l s tr e n g th . W alls m a y be m ade h ea v ie r . . . th e re is n o co m p u lsio n to sacrifice s tu rd y w a ll th ic k n ess to g a in h e a t resistance.

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10 A N A L Y T I C A L E D I T I O N Vol. 6, No. 3

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AMONG n ew “ PR E C ISIO N ” laboratory devices to h elp you speed up your te s tin g ro u tin e, th e n ew “ PR EC ISIO N ” T riple-D rive Stirrer is easily th e m o s t n o tew o rth y . B ein g lig h t in w e ig h t, co m p a ct and p ow erful, b u ilt for easy h a n ­ d lin g and low co sto p cra tio n , th is h a n d y u tility stirrerp osses- ses several exclu sive featu res con d ucive to id eal stirrer per­

form an ce • S w itch con trol gives speeds o f 480, 700 and 830 R .P .M ., w ith p le n ty o f pow er to h a n d le th ree stirrin g jo b s a t th e sa m e tim e . • T w o sp in d le sock ets tra n sm it pow'er th ro u g h a d oub le w orm gear drive to tw o stirrer rods, ru n ­ n in g a t th e sa m e speed; o n e rod is u su a lly driven b y an auxiliary flexible sh a ft (available extra) • E ith er drive sock et w ill tak e th e stan d ard ch u ck or th e flexible sh a ft. T h e stirrer ch u ck takes rods in d ia m eter and in c lu d es a tw o- step m e ta l p u lley for driving a third stirrer. • T o su sp en d th e stirrer in eith er a h o rizo n ta l or vertical p o sitio n , i t is eq u ip p ed w ith a 90° m o u n tin g bracket.

-*• • T h e h a n d y t h r e e - s p e e d s ic itc h is b u i l t r ig h t i n t o t h e m o t o r h o u s in g f o r a c ce ssib le fin g e r ­ tip c o n tr o l.

K W IK -SET CLAMP HOLDER N ew est a m o n g u tili ty c la m p s is th is K W IK -S E T C la m p H o ld er, m a d e e n ­ tire ly o f e ith e r M o n el M e ta l o r S ta in ­ less S te e l, id e a l la b o r a to r y m e ta ls c o m b in in g g r e a t s t r e n g th w ith c o r­

ro s io n re s is ta n c e . T h e y w ill n o t r u s t . T h e ir s p r in g a c tio n e n a b le s th is c la m p h o ld e r to e x e rt a firm g rip o n ro d s o r c la m p s te m s w i th o u t th u m b screw s o f a n y k in d . J u s t slip th e h o ld e r over th e s u p p o r t r o d a n d slid e th e a u x ilia ry ro d o r c la m p in to p la c e . T h e r o ta t i n g c a m h a s s e p a r a te n o tc h e s fo r h o ld in g ro d s f r o m to in d ia m e te r . 12718 M o n el M e ta l. P ric e A Cl 12749 S ta in le s s S te e l. “

T w o d r i v e s o c k e ts in s te a d o f o n ly o n e . D o th s o c k e ts ta k e s t i r ­ rer p u lle y iv i t h c h u c k or a u x ilia r y fle x ib le s h a f t .

N o tic e th e p o s i t i v e d r i v e c lu tc h . J u s t slip t h e s h a f t i n t o th e s o c k e t — i t lo c k s i n s t a n t l y , y e t is e a sy to r e m o v e .

D o e sn ’t o b s c u r e a n y p o r tio n o f t h e b u ­ r e t t e m a r k i n g s , sin c e th e s p r in g c lip s b e a r a g a in s t th e sid es o f th e b u r e t te ,

le a v in g a ll o f th e g r a d u a tio n s f u lly v isib le. N o t h u m b screw's, n o a u x ilia ry s p rin g s o r d e lic a te p a r t s . L ig h t in w e ig h t, s ta m p e d m e ta l c o n s t r u c tio n th r o u g h o u t , w ith sp rin g « g rip r o d c la m p a n d ru b b e r-c o v e re d b u r e t te g rip s . G rip s e x e rt j u s t th e r i g h t p re s s u re , w ith n o d a n g e r o f b u r e t t e b re a k a g e . C e n te r d is ta n c e b e tw e e n b u r e t te s 7-

12771 S ta in le s s S te e l...$2.00 djj "I C f A 12775 B r a s s ... ...

“ PRECISIO N” T R IPL E -D R IV E STIR R ER , N o. 18324 in c lu d in g a d ju s ta b l e c h u c k w it h a tw o -s te p p u lle y ; m o u n t i n g b r a c k e t fo r fa s te n in g to s u p p o r t ro d s ; a n d six fe e t o f ru b b e r-c o v e re d e le c tric c o rd w ith ru b b e r-c o v c re d p lu g . O p e ra te s o n e ith e r s \ f \ A .C. o r D .C ., 110 v o lts o n ly . P r ic e ... HL I I 11 I 18325 F lex ib le S h a f t o n ly . P r ic e ... $4.00

A B O V E — a ty p ic a l tr ip le -d r iv e s t i r ­ r e r s e t - u p , u t i l i s i n g t h e s ta n d a r d c h u c k , fle x ib le s h a f t a n d a u x ilia r y s tir r e r p u lle y .

m

L E F T — C lo se u p v ie w o f t h e tr ip le - d r iv e s tir r e r u n i t . F le x ib le s h a f t is e x tra .

•

FULL-VIEW BURETTE

CLAMP

A N A L Y T I C A L E D I T I O N

V

6 N

3

I n d u s t r i a 1

AND E N G IN E E R I N G

C h e m i s t r y

P u B L I S I I E D BY T H E A M E R IC A N C H E M IC A L S O C IE T Y Ha r r i s o n E . Ho w e, Ed it o r

M a y

15, 1934

Quantitative Spectroscopic Analysis of Solutions

W a l l a c e R . B r o d e a n d J a m e s G. S t e e d , D e p a rtm e n t of C hem istry, T h e Ohio S ta te U niversity, C olum bus, Ohio

T

tained on th e quantitative esti­

m ation of columbium, beryllium, titanium , vanadium , tungsten, iron, molybdenum, chromium, lead, and cobalt. D a ta on a few of these elements (chromium, lead, and cobalt in particular, 5) have been prepared by other

C alibration curves have been determ ined fo r the quantitative spectrographic a n a ly sis o f colum ­ bium , beryllium , tita n iu m , vanadium , tungsten, iron, m olybdenum , chrom ium , lead, a n d cobalt.

These curves are given in both p e r cent o f ele­

m ent a n d logarithm o f the p e r cent o f element present. T he average deviation in Ihe deter­

m in a tio n o f sam ples o f kn o w n com position was less than 5 p er cent o f the know n concentration.

Figure 1 -B). A logarithmic sec­

to r (3, 3) was used in front of the slits of each of these in tru - ments, actuated by connection with th e sta rte r knob of a sim­

ple alternating current electric clock. In a modification of th e Tw ym an and Ilitchen solution spark ap paratus ^{2 2}-gagc copper electrodes were used for both th e upper and lower electrodes workers, b u t using different line

pairs from those in the present analyses.

The m ethod of analysis follows in general th a t described by Tw ym an and H itchen (.5) with certain modifications in the apparatus and manipulation. Two different quartz spectrographs were used in this study, a large Hilger (E-185) Littrow spectrograph (linear dispersion 7000 to 2000 A. = 100 cm., Figure 1-/1) and a medium Bausch and Lomb Spectro­

graph, No. 2820 (linear dispersion 7000 to 2000 A. = 21 cm.,

in place of the previously rec­

ommended carbon and gold electrodes. A Pyrex je t was found to be as satisfactory as a quartz jet. T he copper lines produced in the spectra (Figure 1) were n ot objectionable and m ay reduce to some extent th e slight error due to an ex­

cess of a foreign anion in the solution to be tested.

The spark was produced by a 20,000-volt 2-kilovolt-am ­ pere transform er. The prim ary (110 volt) circuit had a resistance in it, to perm it the passage of about ¹ am pere.

Ta b l e I . Qu a n t i t a t i v e Sp e c t r o g r a p h i c An a l y s is o f So l u t i o n s

Co m po und Us e d

C olum bic a n h y d rid e B eryllium sulfate

B eryllium su lfate T ita n iu m dioxide V anadic anh y d rid e

T u n g stic a n h y d rid e F erro u s am m onium

su lfate M olybdic a n h y d rid e C hrom ic an h y d rid e Lead n itra te C o b alt chloride

Methodof So lutio n

K jC O j fu sion plus w ater W a ter p lu s 2% HiSO<

W ater plus 2 % HjSO<

Sodium pyro su lfate fusion plus 5 % HTSOi

N aO H (calcu lated a m o u n t plus 2 % )

W a te r p lus 2 % HsSO<

2 % ) W ater

W ater plus 2 % H N O j W ater plus 2 % HC1

Conc en tr a tion Ran ge ( El em en t)

In t e r n a l Stan dar d i Use d

Co n c e n t r a t io nof Sta n d a r d

Am o u n tof St a n d a r d Ad d edto 100 CC. OF Solu tio n

% G ram s/100 cc. water Cc.

0 .0 0 5 to 1 .0 KMnO« 2 .8 7 6 9 (1% M n ) 20 0 .0 0 0 1 to 0 .1

0 .0 0 0 5 to 1 .0

Bi(NOa)**

5 lIiO

KMnO«

8 .6 5 8 0 g ram s BiOtCOa-

*/* HiO d issolved in excess conc. HNOa and dilu ted to 100 cc. (3.5*/

Bi)

2 .8 7 6 9 (1% M n )

50

0

10

0 .0 0 5 to 1 .0 C rO i 1 0 .0 0 0 0 ( 5 .2 % Cr) 1 6 .7

) 0 .0 0 5 to 1 .0 CrOj 1 9 .2 3 0 8 (10% Cr) 20

0 .0 0 5 to 4 . 0 KMnO< 2 .8 7 6 9 (1% M n ) 5 0 .0 0 5 to 1 .0 C o C lr

6 H ,0

1 6 .1 4 2 4 p lu s 2 % HC1 (4% C o)

20 9 0 .0 0 5 to 4 .0 KîCrjO t 2 .2 6 3 0 ( 0 .8 % Cr) 50

0 .0 0 5 to 4 . 0 NiSO 7H 20

1 9 .1 4 7 9 plus 2% HtSOi (4% Ni)

10 0 . 4 to 4 . 0 Ni(NO*)2-

61 1,0

1 9 .9 9 0 3 plus 2% HN O a (4% m

7 .2 0 5 5 p lu s 2% HC1 (2% M n)

10

0 . 0 5 to 4 . 0 MnCli*

411*0

157

100

Lin e Pair Use d Cb 292 7 .8 2 Â.

M n 2933.06

Be 3 1 3 1 .3 2 ) , , He 3131.97 J unra,olve<1 Bi 3067.73

B e 2651 {6 unresolved lines) M n 2939.31

TiCr V

3383.765 3 368.05 3093.13 C r 3118.65 V 3130.270 C r 3132.053 W 25S9.2 M n 2593.733 F e 2382.039 Co 2378.62 M o 2848.21 C r 2849.83 C r 3578.687 -Vi 3524.543 l’b 3683.472 Ni 3619.393 C o 3453.514 M n 3441.997

158 A N A L Y T I C A L E D I T I O N Vol. 6, No. 3

CO'«*

<N CO

f t

t~eot-

<N<N

coco V

i. M i l lit

ii

i li

l i i i . l i i

i ii li l i i i iíili

i 1.1, lili

i L l i i l j i iliit

A F iG u n K 1 .

% M o

0 .005

0 .0 5

0 .25

0 .5 0

0 .7 5

1.0

1.5

7

0 .5

0.25

0.1

0.05

0 .005

0.0005

Spectru m Photographs A . V ariation of concentration of m olybdenum w ith chro­

m ium as intern al s tan d a rd .

B . V ariation of co n centration of beryllium w ith m an ­ ganese as in te rn a l s tan d a rd .

A condenser (0.005 microfarad) was shunted across the sec­

ondary term inals of the transformer.

The solutions were prepared by weighing the q u an tity of pure m aterial required to m ake a given volume of the m ost concentrated solutions used and diluting these w ith distilled w ater or other indicated solvent to yield the required con­

centrations. A known am ount of the solution of th e substance selected for the internal standard was then added to a definite volume of each solution and a photograph made of its spark spectrum.

(The photographs were taken on E a st­

m an 33 plates and developed with the E astm an formula D-76 developer with controlled conditions of tem perature and tim e of development.) The lengths of the selected pair of lines were measured with a Bausch and Lomb plate magni­

fier containing a ^{2 0}-mm. scale w ith which the length could be determ ined to within 0.02 mm. The lines selected for m easurem ent conformed as nearly as possible to th e requirem ents for ho­

mologous pairs as described by Gerlach and Schweitzer (1). T he difference in length of two lines will represent the ratio of their intensities, since by the use of a logarithmic sector the line den­

sities vary a t a logarithmic rate. The difference between th e length of the line of th e standard and th e length of the line of the element to be estim ated was then plotted against th e per cent of th e element to be estim ated (and also against the logarithm of the per cent

of th e elem ent to b e e s t i m a t e d ) . These d ata are pre­

sented graphically in Figures 2, 3, and 4. Table I indicates th e m aterials used for examination, the m ethod of solution, t h e concentration range, and the line pairs measured.

The curves in Fig­

ures 2 to 4 m ay be used as standard or calibration curves in the analysis of un­

knowns. The pro­

cedure in such an analysis is to pre­

pare a solution as indicated in Table I and, if the concen­

tration of the ele­

m e n t is a p p r o x i ­ m ately known, di­

lute the solutions to a concentration of approxim ately th a t of the center of the c a l i b r a t i o n curve and photograph its s p a r k spectra. I f the concentration is not approxim ately

known, solutions should be prepared by tenfold dilution, so th a t each solution has one-tenth the concentration of each preceding solution. Three or four such solutions will in nearly all cases cover the desired concentration range. To each solution is then added the indicated am ount of solution containing th e inter­

nal standard and th e spark spectrum is p h o t o g r a p h e d . In obtaining these spectra the m ost dilute solutions should be photographed first and then th e more concentrated in th e order of their in­

creasing concentration. This procedure reduces th e possibility of contam ination of dilute solutions with th e stronger solu­

tions. The minimum q u an tity of solu­

tion upon which the authors have made observations is about 2 cc. B y th e use of capillary tubing, however, it should be possible to use micromethods and obtain satisfactory analyses on 0.5 cc.

or less. T he am ount of unknown ele­

m ent in th e solution is determ ined by measuring the lengths of th e standard and unknown lines and subtracting the standard from th e unknown len g th ; from the calibration curve it can be seen th a t this difference in length will represent a definite per cent of th e element for which th e analysis is made.

In Figure 2, the chromium, lead, and cobalt curves are shown together so as to indicate variations in th e sensitivity range of the lines chosen for these ele-

Per Cent

Fig u r e 2. Ca lib r a tio n Cu r v e s for Det e r m in a t io n o f Pe r c e n t a g e o f Un k n o w n El e m e n t from Dif f e r­ e n c e i n Le n g th o f Un k n o w n and

Standard Lin e s

D o tte d lines are lo g arith m of continuous curves. Slope of lo g arith m lines in d icates con­

cen tra tio n range over which th e lino p air selected m ay be used.

Fig u r e 3. Ca lib r a tio n Cu r v e s for De t e r m in a t io n o f Pe r c e n t a g e o f Un k n o w n Elf.mf.n t from Dif f e r e n c e in Le n g th o f Un k n o w n and Stand­

ard Lin e s

M ay 15, 193-1 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 159 merits. As ■nil! be

noted, the logarithm curves have differ­

ent slopes which cor­

respond in general to the s e n s i t i v i t y r a n g e , c h r o m iu m h a v i n g a n a r r o w r a n g e , l e a d a medium range, while cobalt has the widest concentration range over w h i c h t h i s s p e c t r o g r a p h i c method of analysis c a n b e a p p l i e d . This range of useful c o n c e n t r a t i o n for s p e c t r o g r a p h i c analysis is limited on the low concentra­

tion side to the in­

trinsic intensity of the line and its ability to produce a rea­

sonable photographic image, on the upper side by the point where the logarithm of the concentration plotted against the

Fig u r e 4. Ca lib r a tio n Cuhvesfor De t e r m in a t io n o f Per c e n t a g e of

Bery llium

0.00 to 0.12 p er c en t in up p er curve, 0.0 to 1.0 per c en t in lower curve.

difference in line length ceases to follow the straight line obtained for the lower concentrations and begins to approach a constant value.

W ithin this working range of concentration the error of observation was less than 5 per cent of the observed value.

While this is a rath er large error where concentrations greater than ¹ or ² per cent are concerned, the value of the m ethod increases for more dilute solutions where the error in deter­

mination of a solution containing ^{0 . 0 1} or ^{0 . 0 0 1} per cent of the element will still be less than 5 per cent of the observed value.

Li t e r a t u r e Ci t e d

(1) Gerlach and Schweitzer, "Chemische Em issionspektralanalyae,”

Leopold Voss, Leipzig, 1931.

(2) Hamburger and H olst, Z. wias. Phot., 17, 205 (1918).

(3) Soheibe, “Spektroskopische A nalyse,” A kadem ische Verlags- geseUscbaft, Leipzig, 1933.

(4) T w ym an et al., Trans. O ptical Soc. (London), 31, 169 (1930);

32, 1 (1931).

(5) T w ym an and H itchen, Proc. Roy. Soc. (L ondon), A 133, 72 (1931).

Re c e iv e dA pril 2 7, 1933. P resen ted before th e D ivision of Physical a n d Inorganic C hem istry a t th e 85th M eeting of th e Am erican Chem ical So­

ciety, W ashington, D . C ., M arch 26 to 31, 1933.

Covering Capacity (on Water) of Aluminum Bronze Powder

J u n i u s D . E d w a r d s a n d R a l p h B . M a s o n , A lum inum R esearch L aboratories, N ew K ensington, P a.

T

acteristically different from the granular particles of nonmetallic pigments. They differ so much in shape, structure, and composition th a t th e methods of examination and testing, well developed and standardized for other pig­

m ents, are in m any cases inapplicable to th e study of alumi­

num bronze powder. Aside from their flake-like shape and m etallic base, the flakes differ from m ost granular pigments in having a film of polishing agent on their surface. This thin film, usually containing stearic acid as the m ajor ingredient, modifies the appearance of th e flakes and their general behav­

ior when dispersed in a paint vehicle. The interfacial rela­

tions between powder and vehicle, as well as the size and shape of the flakes, play a p a rt in the im portant phenomenon, known as “ leafing.”

F or commercial purposes, it is custom ary to grade powders according to the approxim ate mesh size of the largest flakes.

A stan d ard varnish powder, for example, has all been through a 140-mesh screen or its equivalent. While a screen analysis m ay give some idea as to th e m ajor dimensions of th e flakes, it tells little or nothing about th eir thickness (or thinness).

Obviously, th e thinner the flakes, th e more flakes of any par­

ticular size per pound of powder. Furtherm ore, the th ic k ­ ness of flake will affect th e leafing characteristics of the pow­

der. D uring an investigation of the properties of aluminum bronze powder, the authors developed a m ethod for measuring the average thickness of bronze powder flakes, which has been found very useful over a period of years. An outline of th is method was first described in 1927 (1). Since then the m ethod has been standardized in detail and technic of opera­

tion.

The m ethod depends on the assumption th a t if all the flakes in a given weight of powder could be spread out in a film one

flake thick and packed close so as to eliminate interstices between the flakes as far as possible, the thickness could be calculated from the area of the film, its weight, and th e den­

sity of the powder. A film which approxim ates these condi­

tions can be obtained by proper m anipulation of the bronze powder on a clean surface of water. A shallow rectangular pan with a flat rim is used as the container for th e w ater and two flat, rigid strips of glass or m etal which ac t as barriers are laid across the width of the pan to define the ends of th e film of powder whose area is to be m easured. W hen a weighed am ount of powder is carefully dusted onto the w ater surface which completely fills the pan, it tends to spread out in a thin leafed film. The flat barriers, resting on th e rim of the pan near each end, perform a very im portant function in “ coaxing”

the powder into a film one flake thick. T he results of the- measurem ent are expressed in term s of th e area in square centim eters covered by a gram of powder and this value is term ed th e covering capacity. I t should n ot be confused w ith th e so-called covering power (square feet per gallon) of a p ain t.

Langm uir (2) and others have shown how stearic acid alone can be spread out on w ater in a film one m olecule thick, and th e dimensions of th e molecule estim ated in th is way. In this experim ent th e polar molecules of stearic acid are uniformly oriented with th e carboxyl group directed to­

wards the w ater interface. In th e case of the polished alum i­

num flakes, the film of stearic acid, m any molecules thick, appears to be oriented and fixed upon the flakes. T he powder flakes in th e present method are only p a rtly w et by th e w ater and float upon the surface. B y m oving the m etal strips back and forth upon the side rims of the pan, th e floating film of powder between them can be stretched and compressed m uch like a fabric until all the flakes have been brought into the w ater interface. The powder is then compressed by m oving

160 A N A L Y T I C A L E D I T I O N Vol. 6, No. 3

Fig u r e 1. Te s t Eq u ip m e n t, Show­ in g Method o f Man’i p i i i.ation' o f

Pla te Glass Ba r r ier s

one of th e strips until th e flakes are all touching, as determ ined b y th e tendency of th e film to wrinkle w ith th e slightest addi­

tional compression. Its area is then measured.

De t a il o f Me t h o d

I t has been found m ost convenient to use a shallow rectan­

gular alum inum pan about 14 cm. wide, 60 cm. long, and 1.3 cm. deep. T he vertical walls are ab o u t 1.3 cm. thick and

are machined and finished sm ooth on th e upper surface to insure good contact with the p late glass b a r r i e r s . T w o pieces of heavy plate glass abo u t 2.5 cm.

wide a n d s e v e r a l centim eters longer th a n th e w idth of th e pan are used to confine th e surface film a n d t o w o rk th e p o w d e r u n i ­ formly over th e sur­

face of the w ater.

Before each de­

t e r m i n a t i o n t h e upper edges of th e pan and the plate g l a s s b a r r i e r s should be rubbed with a piece of ordi­

nary paraffin and th e glass plates polished w ith a clean cloth.

W ater is poured into th e pan until the surface is appreciably above th e upper edges of the pan. T he paraffined edges of the pan prevent th e w ater from overflowing. Reasonable care should be taken to make sure th a t th e height of th e w ater surface above the edges of the pan is always th e same. The use of distilled w ater is preferreid and th e tem perature should remain constant a t about 25° C.

T he surface of the w ater in the pan is sw ept from end to end w ith one of th e glass plates to remove th e m ajor portion of surface impurities, such as

d u st or grease. One.

of the glass plates is then laid across the pan near one end.

Any surface im puri­

ties remaining are blown aw ay from the.

w ater surface near the first, glass barrier an d the second glass plate is laid across th e pan near th e first, taking care that, no surface im purities g e t . b e tw e e n t h e two plates. The second barrier is then pushed nearly to the other end oi the pan,sw eep­

ing all impurities be­

fore it. It is hest- to remove these im puri­

ties from the surface between th e barrier and the edge of th e

pan b y sweeping them over th e edge of th e pan w ith a piece of filter paper. T he reason for doing th is is th a t some of these im­

purities m ight creep under th e barrier as it is moved back and forth and cause breaks in the powder film which is to be dis­

trib u ted on th e clean w ater surface between the tw o barriers.

The two glass barriers are left near th e ends of the pan w ith th e clean w ater surface between them . An accurately weighed

Fig u r e 2. Photom icrograph (100 Dia m e ter s) o f Com pressed Filmo f Alu m inu m Bronze Pow der On e

Fla k e Th ick o n Water

sam ple of pow der is then carefully d istributed upon th e clean w ater surface. A small alum inum b o ttle cap m akes a suitable container for weighing th e alum inum powder. A piece of cheese­

cloth o r bolting cloth m ay be fastened over th e open end of th e cap and th e powder distributed on th e w ater surface b y gently tapping th e inverted cap. T he container should be held close to th e clean w ater surface and moved back and forth to insure uniform distribution. An alternative m ethod, and th e one usu­

ally employed, is to pour th e powder carefully from the. edge of th e weighing container directly onto the w ater surface, care being taken not to get too m uch pow der in one place. T he above operations should be carried out in a draft-free room.

A fter th e pow der has been distributed on th e w ater surface, one of th e glass barriers is pushed tow ards th e o th er end of th e pan, sweeping th e pow der before i t for a b o u t tw o-thirds th e length of th e pan, and then pulled back again. T his pushing an d pulling operation is repeated until th e pow der surface is sm ooth an d free from breaks. Leaving th e first barrier in its original position, th e second barrier is then moved back a n d forth in th e sam e m anner.

T he two barriers are th en adjusted u n til th ere are no breaks in th e m etallic film and

w r i n k l e s s t a r t to f o r m n e a r e a c h barrier because of too g reat pressure. One of th e barriers is then moved back u n til ail th e wrinkles a t both ends of th e film are r e m o v e d . T h i s barrier is th en ad­

justed by increasing th e pressure enough to form a few wrinkles and then decreasing th e p r e s s u r e j u s t enough to s m o o th o u t t h e w r i n k l e s . T he b a r r i e r a t th e o th er end is then ad­

justed slightly. T he l e n g t h o f film - be­

tween th e parallel barriers is measured.

T he barriers are again w o r k e d back and

forth three or four tim es, an d a fte r adjusting as before th e length is measured for a second tim e. T his procedure is repeated u ntil th e length of film rem ains constant for th ree consecutive measure­

m ents. Knowing th e w eight of sam ple and th e length an d w idth of th e m etallic film, th e area which one gram of powder will cover can be calculated.

Figure 1 shows th e te st equipm ent and illustrates th e m ethod of m anipulating one of the p late glass barriers. T he film of powder is shown well worked out on th e surface of the w ater between the barriers. T he sm all cup used for weighing th e powder and distributing it over th e w ater appears on the table, ju st in front of th e rectangular pan.

T he weight of powder tak en will depend on th e size of the pan and th e grade of powder used. F o r th e pan described in this paper, a sam ple of standard varnish powder weighing ab o u t 0.1 gram is satisfactory. W hen lining powders are used, a sample weighing 0.05 gram o r less will be sufficient.

I t is preferable th a t n o t m ore th a n abo u t three-fourths of the cleaned w ater surface of th e pan be covered w ith th e powder film. Experience teaches th e operator the size of sam ple necessary for th e pan used. A bout 15 to 20 m inutes are required for m aking each covering capacity m easurem ent.

A skilled operator can m ake duplicate m easurem ents on th e stan d ard varnish, grade of powder which will n o t differ in area by more th a n about 50 sq. cm. for 1 gram of powder. Since ¹ gram of this grade of powder will cover about 4000 sq. cm. of surface, th e m ethod is reproducible to w ithin ab o u t ¹ to ² per cent.

W hen pressure is applied to th e uniform ly distributed pow­

d er film b y moving one of th e glass barriers, it first wrinkles and then folds up as more and more pressure is applied. As th e pressure is reduced th e film unfolds to a uniform surface.

This procedure can be repeated again and again w ithout dis- Fig u r e 3. Ph o tom icro gra ph (100 Dia m e t e r s) o f Ex pa n d e d Al u m i­ n u m Br o nze Po w d er Film a ft e r

Tr a n s f e r e n c e t o Glass Sl id e

5fny K ,

m»

pow der flake was w et w ith th e water. M microscopic ex­

am ination o f a wcil-worked^ powder film shows th a t i t is,, foe all' practical purposes, o n ly one flake thick.

in Figure 2. is shown a photomicrograph, of th e aluminum powder film while on; th e w a te r and compressed for m easure- m eat. T h e photomicrograph was taken w ith transm itted lig h t a n i any' voids appear as bright spots in th e picture.

An approxim ate estim ate is th a t less th a n about 3 o r 4 p e r ce n t o f th e a m t appears as void» uncovered b y powder,

T h e well-worked alum inum pow der film o a a, w ater surface gives an ideal w a y o f obtaining a slide for exam ination under th e microscope. T he pressure on the m etallic film is reduced b y m oving one o f th e glass barriers towards the e n d of the pan. One e n d o f a cleaned microscope slide is dipped into th e w ater a n d th e slide immersed fo r about three-fourths of its length. T h e slide is th e n carefully raised under th e powder film and withdrawn from th e pan. A uniform film o f powder adheres to th e glass slide. T his film is allowed to d ry on the glass slide.. T h e size distribution of the powder particles m ay then be determ ined with the aid of a microscope.

Figure 3 shows a' photomicrograph,, ta k e n b y transm itted light,, of a film of powder spread o n a glass slide.. T he film is n o t com pressed a n d shows th e individual flakes spread out a n d n o t touching.

T h e covering capacity o f various grades o f aluminum: bronze pow der will rang» from ab o u t 3000 to 12,000 sq , cm. per gram o f powder, although both higher and lower values are ob­

tained. T h e low range of values is obtained w ith th e so- called¹ “ varnish’’ grades o f powder an d the- higher values are obtained with, gome of th e lining powders- Bronze powders are usually screened during m anufacture in order to lim it th e maximum- size of particle present in a n y grade. Even though a screen analysis m a y indicate th a t a series of powders a re v e ry close together- in mesh size, the covering te st m ay

dem onstrate a considerable variation in average thickness o f flake. I n T able I are given d a ta o n a series of pow ders ob­

tained from, different commercial sources. T h e y are graded about th e same commercially,, b o th on mesh, size and' ap p e a r­

ance, b u t th e maximum covering capacity exhibited is about TO' p e r cent greater th a n the- minimum.. W hile high, covering capacity Is, in general, a desirable characteristic;, th e conclu­

sion does n o t necessarily follow th a t the: highest covering power is alw ays th e best, as other characteristics m u st be considered in the evaluation of a powder fo r a n y p articu la r use:

Tabue !.. Comparison: o v C ovaacf» C kM crrv ow W.vrzo. a s b Musit CitAaAr.TaiiisTics ov A traic irar Bconze Powhehs

-ScnKSÎf A.V.\Hr3IH—

CtiV'dnrxa 0 ru 2 0 0 ' On 323- Through 3ampi.b Capacity me*h screen mesh screen 32-T-mesh scr

% c.m. fijrwnt- % % or,/ty

t .1040 M m 5 4

2 .1440 U 29 30

3 3720 32 ¿50

4 4720 ia 22 50

5 5200 17 22 5n

While for m ost purposes,, th e covering, capacity expressed in square centim eters per gram is sufficient, th e calculated average thickness of flak» is also o f interest. T he den sity of aluminum bronze powder is ab o u t 2..5 grams p er cc. and cover­

ing capacities of 3000 to I2;000 sq. cm. per gram correspond with a flake thickness of about 0.0013 to 0.0003 m m , (0.000050 to 0 . 0 0 0 0 1 2 inch),

LroEnATunffi Cited

(1) EMwarritt, X. D tv "Aluminum Bronze Powder a m i A luminum Paine,” p. 14, Cliimiicai Catalog; 1027.

(2) Langjnuir, Ir v in g / . A m . Chevi. Snn.y 39, 1348 (1017).

Rkckivzo Sfarch t, 1934. Presented hefora tlm Dlviaion of Paint ami Var­

nish Chemistry at the STtii M^eecintr of the American Chemical Society,. SJfc.

pBter.nhiirfi, Fla., Sfarch 2.1 to 30». 1034.

Analysis of Mixtures of Oxalic and Citric Acids by Titration with Ceric Sulfate

J . A. Wtthtww w L R , Stpherd, E , L Fcxmeh, and L. M . Ck k e'e e s s e s* Iow a S ta te College, Ames, Iow a

T

tance: T he present situation has been reviewed by M a y a n d H errick {S';.. One of th e m ost im portant develop­

m ents is th e production: o f citric acid, in which oxalic acid is likewise produced. I n order to m ake adeqiiate quantitative studies a t th is ferm entation, a satisfactory analytical m ethod o f analysis for tiieae acids needs to be developed, for, as sta te d b y Currie (J), while the present methods “give fairly satisfactory résulta i f used w ith discretion and patience, a really convenient a n d accurate method fo r estim ating citric acid is still w anting.” The present com munication describes a. m ethod: o f analyzing citric acid in th e presence of oxalic acid.

Oxalic acid is a very good reducing agent, and when pres­

e n t alone it m a y b e titra te d easiTy an d accurately w ith any sta n d ard oxidizing agent such as perm anganate. Citric acid, however, does n o t give a sharp en d point w ith moat oxidizing agents, and the firwl products o f these reactions are n o t definitely known» Various m ethods for th e analysis of citric ac id have been suggested, some requiring rath er elabo­

rate m anipulation. One o f th e m ost common methods, of which there are numerous mollifications,, is oxidation, with

potassium permanganate, which; has been stu d ied in different phases b y Perdrix (7), Beniges (,?), P r a tt (S), K unz (5), H artm ann and Hillig ($), Williams, Mueller, am i N iederl (Iff) used a photoelectric eell in a colorimetric m ethod, and Currie (2) developed a fairly accurate iodometric m ethod,

W illard and Young (.9) described the use o f ceric sulfate as a sta n d ard oxidizing agent and applied it to th e oxidation of organic .matter, including oxalic an d o ther organic acids,, as d id B erry ( f) , T his oxidizing agent seemed to offer possi­

bilities for th e determ ination of oxalic an d citric acids in mix­

tures,

EXPERTM'E-VTAI.

T he m ethod used is essentially differential titra tio n o f th e m ixture of th e two- acids, determining, first th e to ta l acidity of th e m ixture b y titra tin g w ith sta n d ard base using phenol- phthalein an d th e n th e total reducing power o f th e m ixture b y titra tin g w ith ceric sulfate solution. W hile oxalic acid is oxidized quan titativ ely to carbon dioxide and w ater b y ceric sulfate,, citric acid is not, a n d th e fraction oxidized is dependent upon several factors, including tem perature, con­

centration o f both, sulfuric acid a n d ceric sulfate,, an d th e tim e o f standing.