Industrial and Engineering Chemistry : analytical edition, Vol. 14, No. 6

INDUSTRIAL ^{A N D} ENGINEERING CHEMISTRY

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

HARRISON E. HOWE, E DITO R ISSUED JUNE 15, 1942 VOL. 14, NO. 6 C ONSECUTIV E NO. 12

D e t e r m i n a t i o n o f F l u o r i n e a n d O t h e r H a l o g e n s i n O r g a n i c C o m p o u n d s ...

Philip J. Elving and W. B. Ligett 4 49 R e s id u e V o lu m e M e t h o d o f S o l u b i l i t y D e t e r m i n a ­

t i o n . Thomas H. Vaughn and Eugene G. Nutting, Jr. 4 54 D e t e r m i n a t i o n o f T a n n i n S u b s t a n c e s i n B o ile r

W a t e r s ...A. A. Berk and W. C. Schroeder 456 N e w T e c h n i q u e f o r A d s o r p t i o n S t u d i e s ...

Janies Coull, H. C. Engel, and Joseph Miller 459 A s sa y o f T h y r o i d a n d I t s P r e p a r a t i o n s ...

J. L. Deuble and John Wilkinson, Jr. 463 D e t e r m i n a t i o n o f S a l t s i n C r u d e O i l ...

Clarence A. Neilson, J. Stewart Hume, and Bert H. Lincoln 464 D e t e r m i n a t i o n o f I o d a t e a n d O t h e r O x id iz in g A g e n t s

i n P r e s e n c e o f C u p r i c S a l t s ...

Ernest H. Swift and Thomas S. Lee 466 D e t e r m i n a t i o n o f S m a l l A m o u n t s o f G o ld w i t h

S t a n n o u s C h l o r i d e ...

Colin G. Fink and Garth L. Putnam 4 68 P h o t o m e t r i c D e t e r m i n a t i o n o f P o t a s s i u m ...

I. W. Wander 471 F ib e r I d e n t i f i c a t i o n S t a i n ...

H. L. Davis and H. J. Rynkiewicz 472 P o l a r o g r a p h i c D e t e r m i n a t i o n o f P o t a s s i u m , S o d i u m ,

a n d L i t h i u m . . . Ignace Zlotowski and I. M. Kolthoff 473 D e t e r m i n a t i o n o f O il i n M e t a l T u r n i n g s ...

David Margolis 478 D e t e r m i n a t i o n o f T r a c e s o f C o p p e r i n W o r t, B e e r ,

a n d Y e a s t ...Irwin Stone 479 D e c o m p o s itio n T e m p e r a t u r e s o f S o m e A n a l y t i c a l

P r e c i p i t a t e s . . M. L. Nichols and R. H. Lafferty, Jr. 481 G la s s V a lv e P r e s s u r e R e g u l a t o r ...

Marion J. Caldwell and H. N. Barham 485 O z o n e a s A n a l y t i c a l R e a g e n t . D e t e r m i n a t i o n o f

V a n a d i u m , C e r i u m , a n d M a n g a n e s e ; D e t e r m i n a ­ t i o n o f I o d i d e s ...

Hobart H. Willard and Lynne L. Merritt, Jr. 486

D e t e r m i n a t i o n o f P a l l a d i u m w i t h B e t a - F u r f u r a l - d o x i m e ...J. R. Hayes and G. C. Chandlee 491 S e m i a u t o m a t i c F r a c t i o n a t i o n . Bassett Ferguson, Jr. 493 F i l m B a la n c e a s A n a l y t i c a l T o o l f o r B io lo g ic a l a n d

F o o d R e s e a r c h ...

George E. Boyd and William D. Harkins 4 9 6 P e r f o r m a n c e o f S o m e D i s t i l l a t i o n C o l u m n s f o r

F r a c t i o n a t i o n o f T e r p e n e s . . W. David Stallcup, Robert E. Fuguitt, and J. Erskine Hawkins 503 T r a p t o P r e v e n t B a c k flo w f r o m S u c t i o n P u m p s . .

Arthur E. Meyer 505 A p p a r a t u s f o r D e t e r m i n i n g D i s t i l l a t i o n R a n g e s a t

R e d u c e d P r e s s u r e s ...

C. E. Watts, John A. Riddick, and Fred Shea 506 S t u d y o f t h e E l e c t r i c H y g r o m e t e r ...

R. N. Evans and J. E. Davenport 507 A d a p t e r s f o r C o l le c ti o n o f D i s t i l l a t i o n F r a c t i o n s

u n d e r V a c u u m ...

John W. Patterson and Robert W. VanDolah 511 F e r r o c y a n i d e M e t h o d f o r S e p a r a t i o n o f H a f n i u m

f r o m Z i r c o n i u m ...

Walter C. Schumb and Frank K. Pittman 512

M I C R O C H E M I S T R Y :

D e t e r m i n a t i o n o f A r s e n ic i n O r g a n i c C o m p o u n d s Henry A. Sloviter, W. M. McNabb, and E. C. Wagner 516 N e w P r o c e d u r e f o r D e t e c t i n g A c i d i t y ...

Fritz Feigl and Paulo E. Barbosa 519 M e r c u r y A z o t o m e t e r f o r D e t e r m i n a t i o n o f O r g a n i c

N i t r o g e n b y t h e M i c r o - D u m a s M e t h o d . . . . R. G. Clarke and W. R. Winans 522 D e t e r m i n a t i o n o f E t h y l A lc o h o l b y M i c r o d if f u s io n

Theodore Winnick 523 S e m i m i c r o d e t e r m i n a t i o n o f C a r b o n ...

R. M. McCready and W. Z. Hassid 525

T he American C hem ical S ociety assum es no responsibility for the statem ents and opinions advanced by contributors to its publications.

25,900 copies of th is issu e printed. C opyright 1942 b y American Chem ical Society.

P u b lic a tio n O ffices E ditorial O ffice: 1155 1 6 th S t r e e t , TS. W ., W a s h in g t o n , D . C.

Telephone: R e p u b lic 5301. C a b le: J ie c h e m (W a sh in g to n )

.P u b lish e d b y th e Am erican C hem ical S ociety, Pu blication Office, 20th ¿c Northampton S ts., E aston , Penna. E ntered as second-class m atter a t the

^ost Office a t E aston, P en n a., under th e A ct of M arch 3, 1879,, as 24 tim es a

^ a r . Industrial E d ition m on th ly on th e 1st; A nalytical E dition m onthly o a th e 15 th. A cceptance for m ailing a t special rate of postage provided for m Section 1103, A ct of October 3, 1917, authorized Ju ly 13, 1918. .

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copies: Industrial E d ition , $0.75; A nalytical E dition, $0.50. Special rates to members.

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cannot be accepted as th e reason for honoring a claim . Address claim s to Charles L. Parsons, Business M anager, 1155 16th Street, N . W ., W ashington, D . C ., U. S. A.

4 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 Vol. 14, No. 6

A g ro u p o f c h e m is ts m a k in g c o n tr o l tests in th e M e r c k A n a l y t i c a l L a b o ra to r ie s.

M I C R O A N A L Y T I C A L C H E M I C A L S

T h e in c r e a s e d in t e r e s t in M ic r o a n a ly t ic a l C h e m is tr y d u r in g th e p a s t fe w y e a r s h a s r e s u lte d in th e n e e d fo r a c o m p r e h e n s iv e l i n e o f R e a g e n t s s u ita b le fo r t h is w o r k .

A c c o r d in g ly , M e r c k & C o . I n c . h a s d e v e lo p e d a s p e c i a l l i n e o f r e a g e n t s fo r b o th s e m i- a n d f u ll- m ic r o a n a ly t ic a l p r o c e d u r e s . A lt h o u g h a c o m p a r a t iv e ly s m a ll p a r t o f th e c o m p l e t e l i n e o f M e r c k L a b o r a to r y a n d R e a g e n t C h e m ic a ls , th e y n e v e r t h e le s s c o m p r i s e a v e r y im p o r t a n t g r o u p .

M ic r o a n a ly t ic a l m e t h o d s o f a n a ly s is r e q u ir e b u t s m a ll a m o u n t s o f c h e m ­ ic a ls , b ut in o r d e r th a t c o r r e c t r e s u lts b e o b t a in e d , th e y m u s t b e o f a h ig h d e g r e e o f p u r ity , a n d t e s te d fo r th e p a r tic u la r p u r p o s e fo r w h ic h th e y a r e in t e n d e d .

T h e M e r c k A n a ly t ic a l L a b o r a to r ie s p la y a v ita l p a r t in g u a r a n t e e in g th e q u a lity a n d d e p e n d a b ilit y o f M e r c k M ic r o a n a ly t ic a l C h e m ic a ls .

W r i t e f o r f u r t h e r in f o r m a t i o n a n d li s t of items.

MERCK & CO. Inc. R A H W A Y , N. J*

N E W Y O R K • P H I L A D E L P H I A • S T . L O U I S • In C a n a d a : M E R C K & C O . L td ., M o n t r e a l a n d T o r o n to

June 15, 1942 A N A L Y T I C A L E D I T I O N 5

P ro tectio n

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A R E Y O U E Q U IP P E D TO SEE THE D IF F E R E N C E ?

• R utile and anatase, tw o im p ortan t o x id e s o f T i 0 2, have identical chem ical form ulae, yet each has a radically different behavior from th e other. T h eir w ide-spread u se in processes which m ust adhere to "step p ed u p ” p ro d u ctio n schedules make it im p erative that titanium bearing ores and refined oxides b e analyzed by a rapid, accurate m eth o d .

Such a m eth o d is available w ith th e G -E X R D U n it.

Titanium o x id es w h e n analyzed by x-ray diffraction may reveal three types o f patterns: Pattern (A ) w as p rod u ced by pure rutile; Pattern (B) w as registered by pure anatase. A mixture o f th e tw o w ill result in Pattern (C ), and th e d en ­ sity o f each pattern w ill g iv e a quantitative in d ica tio n o f the am ounts o f each o x id e present.

From such easy-to-obtain, illustrated data, it is p o ssib le to establish c o m p le te co n tro l o f th e o x id e m ixtures and pre­

vent failure o f m anufacturing processes. For co m p lete information about th e G -E X R D U n it and its application to your prob lem s, address your request to D epartm ent R 4 6 .

GENERAL ELECTRIC X-RAY CORPORATION

2 0 1 2 J A C K S O N B L V D . C H I C A G O , ILL., V . S . A .

T od ay, m ore than ev er before, ev e ry laboratory

— in sch ool, c o lle g e , h ospital or industry— is vitally in terested in c o n se rv in g a n d p ro lo n g in g th e life of its laboratory w are.

This w ar tim e eco n o m y ex ten d s e v e n to the m ost com m on of all laboratory apparatus— the every-d ay test tu b es. The lo n g e r life of

"Pyrex" test tu b es co m es from th e B a la n ced G lass of w h ic h they are m ad e— m ech a n ica lly , therm ally an d c h em ica lly b a la n c e d ; uniform w all thickness; w e ll rou n d ed bottom s w ith e v e n g lass dis­

tribution; w ell tooled rims; an d carefu l a n n e a lin g in specially con stru cted tem perature con trolled lehrs.

T here's no gu essw ork in p u r ch a sin g "Pyrex" test tubes. Labora­

tories m ain tain in g a ccu ra te record s of p u rch a ses a n d replacem ents h a v e p roven to their ow n satisfaction that "Pyrex" test tu b es offer m ost in lo n g er life, greater c o n v e n ie n c e , safety an d econom y.

Figure test tu b e costs not b y the d ozen — but b y the year.

Your laboratory su p p ly d ea ler c a n su p p ly y ou . C onsult Catalog LP21 for com p lete inform ation.

Vol. 14, No. 6

YOU A R E P R A C T I C I N G W A R T I M E

PYREXLABORATORY WARE

14PY R E X ” a n d “ V Y C O R ” a r e r e g is te r e d t r a d e - m a r k s a n d in d ic a te m a n u fa c tu re b y

C O R N I N G G L A S S W O R K S • C O R N I N G , N E W Y O R K

Furnace Fuel Can Be Saved With Help o f C02 Recorder

M EA SU R IN G IN S T R U M E N T S TELE M E TE R S • A U T O M A T IC CONTROLS • H E A T -T R E A T IN G FURNACES Typical instrument panels in Brockway Glass Company, Inc., plants.

One of m a n y w a y s in w h ic h efficiency in the b u rn in g o f fu e l is b e in g in c re a se d to d a y is by the use o f th e M ic ro m a x CO o R e c o rd e r, as a g u id e to f u rn a c e o p e ra tio n .

In in d u s tr ia l p la n ts, C O o is g e n e ra lly sampled a t th e flue to th e w a s te -h e a t b o iler;

and the R e c o rd e r is on th e f u rn a c e ’s co n tro l panel, p e rh a p s h u n d re d s of feet a w a y . T h e installation is c o m p a ra tiv e ly sim p le, a n d th e equipment re q u ire s h a r d ly a n y m ore a tte n tio n than is need ed by a p y ro m e te r.

T h is r a d ic a l sim p lific a tio n w a s a c h ie v e d some y e a rs ag o , by a co m p lete a b o u t-fa c e in the m ethod of h a n d lin g the sa m p le o f flue gas. G as w a s fo rm e rly d r ie d , to p re v e n t its corroding th e a n a ly z in g elem en ts it m u st contact. N o w , th e cell is c o rro sio n -p ro o f, a n d gas is sa tu ra te d . T h u s th e d r y e r m a in te n a n c e is elim in ated , cell m a in te n a n c e is e n d e d , a n d the th eo retical a d v a n ta g e s o f a u to m a tic CO o recording h a v e becom e e n tire ly p ra c tic a l.

Several h u n d re d w a r - r u s h e d p la n ts a re u sin g M icrom ax C O2 R e c o rd e rs, a n d th e list is grow ing.

How L&N Instruments Help In Busy Mills

Combustion in a battery ot soaking pits, in a steel

! ? • ’,!? regulated to save fu el with the help of tins Micromax CO2 Recorder.

A typical case is in th e Jo h n A . R o e b lin g ’s Sons steel m ill, u sin g th e R e c o rd e r p ic tu re d here. T h e C o m p a n y in s ta lle d th is first Micromax sh o rtly a f te r it w-as a n n o u n c e d as a new in stru m e n t. I t w e n t to w o rk in a distinctly “ m a k e -g o o d -if-y o u -c a n ” a tm o s­

phere. It d id m ak e go o d ; a n d CO o h a s jo in e d the other co n d itio n s w h ic h a re k n o w n w ith dependable ac c u ra c y . A n o th e r ste e l-m ill u se r 15 Jones & L a u g h lin , w ith 4 r o u n d -c h a rt in ­ struments.

Potteries Are Users

Among the u se rs o f M ic ro m a x C O o R e ­ corders in the c e ra m ic in d u s tr ie s is I.enox, Inc. A g as-fired k iln h a s used a s tr ip - c h a r t Recorder since it w a s first fire d .

Many C h e m ica l A p p lic a tio n s

Standard a p p lic a tio n s o f M ic ro m a x g a s - analvsis reco rd ers in th e c h e m ic a l in d u s trie s

■nclude: COo in S o lv a v a n d o th e r a lk a li processesj SOp in su lf u r ic a c id m a n u f a c tu r e ; acetone in a i r ; h y d ro g e n in o x y g en a n d j

ox.'gen in h y d ro g e n . E q u ip m e n ts w h ic h w e -tipply m u n c a lib ra te d fo rm , f o r se c re t o r special ap p licatio n s, a r e also com m on.

^ e w ill he g la d to se n d f u r t h e r in f o rm a -

011 or to co n su lt w ith y o u r e g a r d in g a j

sP«>fic ap p licatio n . I

Six d is tin c t jo b s o f te m p e ra tu re -c o n tro l, a r e sh o w n b y th ese p h o to g ra p h s in p la n ts fa c e d w ith w a r -s tim u la te d d e m a n d . T h e y sh o w w a y s in w h ic h B ro c k w a v G la s s C o m ­ p a n y , In c., h a s fo r y e a rs m a in ta in e d its s ta n d ­ a r d s f o r “ C irc le B ” b o ttles w ith th e h e lp of L&N in stru m e n ts.

1. O p tic a l P y ro m e te r, o u r p o te n tio m e te r- ty p e, used fo r c h eck in g , in sp e c tio n , etc., in o p e ra tio n o f th e h ig h - te m p e ra tu r e f u rn a c e s of th e g la s s in d u s try . L ig h t, fa st, a n d easy to use, in a d d itio n to b e in g th e a cce p te d s ta n d a rd o f a c c u ra c y a m o n g o p tic a ls. R e a d s d ire c t in d e g re e s F o r C.

2. T e m p e ra tu r e s a t 3 o f th e h o tte st p o in ts in a g la ss ta n k a re re c o rd e d by th is M ic ro m a x P y ro m e te r. T h e te m p e ra tu re fo r ea c h p o in t is re c o rd e d in a d iffe re n t color.

3. L& N C o n s ta n t P re ss u re C o n tro lle r fo r g la ss t a n k ; sim p le a n d h ig h ly se n sitiv e . It m o v es th e d a m p e r b y m ean s o f th e d riv e - u n it a t its r i g h t; th is h u sk y u n it h a s n / h p , 17 5 0 -rp m m o to r, g e a re d d o w n to g iv e its 2 " - d ia m e te r o u tp u t s h a f t a to rq u e o f 550 l b / f t at 1 rp m .

4. T e m p e r a tu r e o f m o lte n g la ss in e ith e r th e nose o r b o tto m o f a n y one o f six g lass fe e d e rs ( f o r b o ttle m a c h in e s) c a n be checked by flip p in g a sw itc h a n d t u r n in g a knob on th is m u ltip le p o in t te m p e r a tu re in d ic a to r. Its

ra n g e is 0-3000 F . T h is is p r im a r ily a ch eck ­ in g a n d tr o u b le -s h o o tin g in s t r u m e n t ; the te m p e r a tu re s it c a n check a re a lso re c o rd e d b y M ic ro m a x P y ro m e te rs lik e th e o n e d e ­ sc rib e d b elo w .

5. T e m p e ra tu r e s in noses a n d b o tto m s of tw o fe e d e rs a re a u to m a tic a lly re c o rd e d , in tu r n , b y th is 4 -p o in t M ic ro m a x P y ro m e te r.

I t uses p la tin u m th e rm o c o u p le s; h a s a ra n g e o f 1000-3000 F ; c h a r t sp e ed 1" p e r h o u r. Is so f u lly a u to m a tic th a t it r e q u ire s a tte n tio n o n ly once in 2 w eek s, e v en on 2 4 -h o u r d u ty .

6. T h e flow o f flu e-g as a n d a i r th r o u g h the p r e h e a tin g c h eck e r c h a m b e rs o f a g la s s ta n k fu rn a c e is a u to m a tic a lly re v e rse d by th is M ic ro m a x P y ro m e te r. I t m e a s u re s te m p e r a ­ tu re s o f th e rm o c o u p le s in th e c h a m b e rs, a n d sw itc h e s g a s a n d a i r w h e n e v e r th e tw o te m - perature!} re a c h p r e d e te rm in e d d ifferen ces.

F o r re v e rs a l, it em p lo y s a m o to r-d riv e a p ­ p lied to th e r e g u la r r e v e r s in g m e c h a n ism seen in fo re g ro u n d . B y m a k in g r e v e r s a l d e ­ p e n d on te m p e r a tu re r a t h e r th a n on tim e, M ic ro m a x h e lp s sm ooth o u t th e h e a t b a la n c e a n d o th e r o p e r a tin g c h a r a c te r is tic s o f th e fu rn a c e .

I n fo r m a tio n , o r e n g in e e r in g a ssista n c e in a n y w a r - in d u s tr y p ro b le m o f te m p e r a tu re co n tro l is a v a ila b le on re q u e st.

M Ad EN.0720U6)

L E E D S

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ELEC T R IC ^ FU RNACE

^ S l S E D

. . . . S e r v ic e fo r a la r g e c h e m i c a l c o m p a n y w h i c h h a d d if f i c u l t y f in d in g a c a t a l y t i c m a t e r i a l fo r a s e c r e t p r o c e s s . T h e c a t a l y s t h a d t o b e (1) p o r o u s , (2) c h e m i c a l l y i n a c t i v e , (3) r e s i s t a n t t o h i g h t e m p e r a t u r e s , (4) n o n - c r u m b l i n g . O u r e n g in e e r s d e v e lo p e d a s p e c ia l f ir in g o f a s t a n d a r d N o r t o n m i x . T h e c a t a l y s t m e t a l l f o u r r e q u i r e m e n t s .

NORTON COMPANY — WORCESTER, M ASS.

lu n e 15, 1942 A N A L Y T I C A L E D I T I O N

The exchequer standard avoirdupois pound (flat) of Queen Elizabeth

S T A N D A R D In Lot After Lot

Look at the maximum limits o f impurities on the label o f any package o f Mallinckrodt Analytical Reagent. And study a label o f the same chemical o f several months ago or several months later. They will read precisely the same, because Mallinckrodt Chemicals are made to pre-determined standards for precise analysis.

Have a catalogue o f Mallinckrodt Analytical Reagents and other labo­

ratory chemicals right at hand. Send for your copy now.

A L W A Y S S P E C IF Y R E A G E N TS IN M A N U F A C T U R E R ’S O R I G I N A L PACKAGES

M A L L I N C K R O D T C H E M I C A L W O R K S

ST. LOUIS • PHILADELPHIA • MONTREAL

CHICAGO • NEW YORK • LOS ANGELES

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 Vol. 14, No. 6

M ICRO

KJELDAHL DISTILLING APPARATUS

Mounted with nickel-plated bronze Spring-Grip Clamps, specially designed for the convenient and safe assem bly of Microchemical Apparatus, on support with Coors porcelain base and aluminum rod*

M ICRO K JELD A H L D IST IL L IN G A P PA R A T U S, Kirk. A c o m ­ p a c t a n d r u g g e d u n it o f P y r e x g la s s , c o m p l e t e w ith s u p p o r t a n d c la m p s , fo r t h e d e t e r m in a t io n o f n it r o g e n b y t h e u s u a l M ic r o K j e ld a h l m e t h o d s , e lim in a t in g a ll r u b b e r c o n n e c t io n s a n d g r o u n d j o i n t s fr o m t h e d is t il la ­ tio n tr a in . S e e P a u l L. K ir k , “ A O n e - P ie c e G la s s M ic r o - K j e ld a h l D i s ­ t i ll a t io n A p p a r a t u s ,” 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 n a l . E d . ,

V o l. 8, N o . 3 { M a y 1 5 , 1 9 3 6 ) , p . 2 2 3 .

The distilling flask, steam generator and condensing system are made in one piece.

The flask, capacity 35 ml, is provided with an outer jacket in which steam is generated.

Steam reaches the solution in the distilling flask through a Y-tube with one arm sealed into the side of the flask. The stem of this tube extends close to the bottom for emptying the residue after distillation by suction created by removal of the burner from beneath the steam jacket.

The other arm of the \ r-tube is sealed through the wall above the generator to the filling funnel. Above the flask is a trap and head leading directly to the small glass internal condenser which drains through a vertical delivery tube into the receiver.

Water for the condenser and steam generator is introduced through the inlet above the condenser. An overflow and bypass carry the water either to the drain or to the steam generator, which is equipped with an

auxiliary drain tube. Total height of the glass parts approximately 350 mm; maximum width 210 tnm.

7496. Micro K jeldahl D istillin g Apparatus, Kirk, com plete as shown in illustration, con­

sisting of principal glass part, drain tube, filling funnel and receiving flask, 125 ml capacity, all excepting funnel of Pyrex glass, m ounted on support w ith Coors porcelain base, with two nickel-plated bronze Spring-Grip Clam ps, four pinch- cocks and rubber tubing connections, but without burner... 3 2 .5 2 Code W ord... K ijrlf 7-196-A. Principal G lass Part only, with rubber con­

n e c tio n s ... . . ... 2 5 .0 0 Code W ord... K yrm d

M ICRO K JELD A H L D IST IL L IN G A P P A R A T U S, P regl-P arn as- W agner Improved Form . F o r r a p id d e t e r m in a t io n o f n it r o g e n in o r g a n ic s u b s t a n c e s b y s t e a m d is t il la t io n o f a p r e p a r e d d ig e s t o f a m m o n iu m s u l f a t e a n d a d s o r p t io n o f t h e f r e e d a m m o n ia in a n a b s o r b in g liq u id , in a c c o r d a n c e w i t h m e t h o d s o f P r e g l or s im ila r p r o c e d u r e s . S e e P r e g l- R o t h , “ Q u a n t i t a t i v e O r g a n i c M i c r o a n a l y ­ s i s , ” 3 r d E n g l i s h e d i t i o n ( 1 9 3 7 ) , p p . 8 7 - 9 0 .

Glass parts of Pyrex, with pure silver condenser tube, including an anti-bump­

ing tube in steam generating flask and a funnel-shaped collecting tube for con­

densates to prevent contamination of distillate.

Consisting of steam generating flask A, 1000 ml; anti-bumping tube B; steam trapC ; connecting tube D; distilling flask E; connecting tube F; filling funnel G;

condenser with silver inner tube H; collecting tube I; and Erlenmeyer flask J;

mounted on support with Coors porcelain base, necessary Spring-Grip Clamps, holders, ring, wire gauze, pinchcocks, burner and rubber connections.

7492. M icro K jeldahl D istillin g Apparatus, Pregl-P arn as-W agner, Improved Form, com plete as shown in illustration, w ith burner for use on artificial or mixed gases up to 800 B. T. U ... 5 2 .2 9 Code W ord... K yrg p

* Our stocks of both alum inum rods and Spring-Grip C lam ps are lim ited.

ARTH UR H. T H O M A S C O M P A N Y

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

LA B O R A TO R Y A PPARATUS A N D REAG ENTS

WEST W A S H IN G T O N SQUARE, P H IL A D E L P H IA , U. S. A.

C a b le A d d r e 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

D eterm ination o f Fluorine and Other Halogens in Organic Compounds

P H I L I P J . E L V I N G AN D W . B . L I G E T T , P u r d u e U n i v e r s i ty , L a f a y e t t e , I n d .

A m e t h o d f o r t h e a n a l y s i s o f o r g a n i c f lu o r o c o m ­ p o u n d s is p r e s e n t e d . T h e p r o c e d u r e d e p e n d s u p o n d e c o m p o s i t i o n o f t h e c o m p o u n d b y h e a t i n g w i t h a n a l k a l i m e t a l i n a n e v a c u a t e d s e a le d t u b e a t m o d e r a t e l y e le v a t e d t e m p e r a t u r e , a n d d e t e r m i n a ­ t i o n o f t h e r e s u l t i n g a l k a l i f l u o r i d e b y s t a n d a r d m e t h o d s . T h e s a m e t e c h n i q u e s e r v e s f o r t h e a n a l y s i s o f c li l o r o , b r o m o , a n d i o d o c o m p o u n d s a n d h a s s e v e r a l a d v a n t a g e s o v e r t h e p r o c e d u r e s c o m ­ m o n ly e m p l o y e d i n t h e s e d e t e r m i n a t i o n s . A p p l i ­ c a t i o n o f t h e m e t h o d t o v a r io u s t y p e s o f f lu o r o c o m p o u n d s d is c lo s e s n o c o m p o u n d to o s t a b l e t o b e d e c o m p o s e d b y t h e c o n d i t i o n s d e s c r i b e d . A s i m u l ­ t a n e o u s d e t e r m i n a t i o n o f f l u o r i n e a n d c h l o r i n e in c h lo r o f l u o r o c o m p o u n d s m a y b e m a d e . T h e d e ­ c o m p o s i t i o n c o n d i t i o n s le a v e t h e h a l i d e i o n s i n a n e n v i r o n m e n t s u i t a b l e f o r d e t e r m i n a t i o n w i t h o u t a p r e l i m i n a r y s e p a r a t i o n . T h e m e t h o d i s a p p l i c a b l e to s o l i d s , l i q u i d s , a n d g a s e s , i s a c c u r a t e a n d r a p i d , a n d r e q u i r e s n o s p e c ia l a p p a r a t u s o r r e a g e n t s .

T

bility of a sim ple m ethod for determ ining this elem ent, espe­

cially in th e v ery stab le com pounds containing more than one fluorine atom on th e sam e carbon atom . T h e m ethods at present described in th e literature either do n o t work for the more stable com pounds or are described in insufficient detail and w ithout sufficient experim ental verification to perm it their use. T h e standard references on organic analysis fail in m ost cases even to m en tion th e topic (27, 32, 37).

The determ ination of fluorine and other halogens in or­

ganic com pounds resolves itself into tw o parts: (1) destruc­

tion or decom position of th e com pound to convert the halo­

gen into an ionizable form, and (2) determ ination of the halide ion. In the case of organic com pounds containing halogens other than fluorine, th e halide can usually be obtained b y any of several recognized m ethods— e. g., th e Carius m ethod of heating w ith nitric acid in a closed tube, oxidation b y sodium peroxide in a Parr bom b or b y fum ing sulfuric acid, combus­

tion in oxygen, or hydrogenation in th e presence of a suitable catalyst. T h ese m ethods are of varying degrees of conven-

• ience as regards sim p licity of apparatus, tim e required, and skill necessary in th e operator.

The separation and determ ination of chloride, bromide, or iodide ion are well taken care of b y standard m ethods of

know n accuracy. H ow ever, if fluorine is present, difficulties are introduced due to the great sta b ility of the carbon to fluorine bond in arom atic com pounds and in highly fluorinated aliphatic com pounds. T h e m o st w idely used m ethod for th e recovery of halide ion from organic com pounds, th e Carius m ethod, cannot be used for fluorine since the hydrogen fluo­

ride or hydrofluoric acid form ed attack s th e glass of the reac­

tion tube. In speaking of th e analysis of certain chlorofluoro- propanes, H enne and R enoll (19) assert th a t the chlorine in these substances could be determ ined on ly by the Carius m ethod, which required a w hole w eek of continuous heating a t 250° to 300° C. to yield q u a n tita tiv e results. All other m ethods gave an incom plete decom position. As an indica­

tion of th e sta b ility of th e carbon to fluorine bond, M eyer (28) asserts th a t th e other halogens in halofluoro com pounds can be determ ined b y the Carius m ethod or by lim e fusion in glass w ithout sp littin g o u t the fluorine.

T h e m ethods suggested in the literature for the decom posi­

tion of organic fluorine com pounds are classified in T able I.

M ost of th e fluorine com pounds for w hich analyses are re­

ported are of com paratively low fluorine con ten t, com m only h aving on ly a single fluorine atom in a m olecule of high m o­

lecular w eight. T his choice of com pounds m akes th e m ethods appear better than th ey actu ally are for tw o reasons: (1) a.

relatively large error on th e basis of fluorine present appears as a sm all percentage error; and (2) applicability of the m ethod to th e more stable com pounds containing tw o or three fluorine atom s on a single carbon atom is n ot tested . In the present investigation, how ever, m any of the com pounds analyzed were chosen because the}’- were supposed to be particularly stable and could n o t be analyzed by the m ethods described in the literature.

Ta b l e I. De c o m p o s i t i o n o f Or g a n i c Co m p o u n d s Co n t a i n­ i n g Fl u o r i n e

I. O xidation M ethods

A. C om bustion in oxygen (5, 25, 31, 34)

13. Fusion w ith sodium peroxide (12, 14, 22, 35, 42) C. Alkaline oxidation (4)

II. R eduction M ethods

A. Com bustion in hydrogen (8, 46)

B. T reatm ent with sodium in liquid am m onia (47) C . Alkali m etal fusion (2, 23, 36, 39, 43)

D . T reatm ent w ith alkali m etal in organic solven t (48, 49) I II. M ethods Involving Alkaline Fusion

A. Fusion with calcium oxide (3, 10, 11, 20, 24, 29, 40, 4U 44) B. Fusion w ith sodium carbonate (6)

IV . M ethods Involving R eaction w ith Silicon D ioxide A. Corrosive action on glass (7, / 7, 33)

B. Com bustion over silicon dioxide using oxygen and hydrogen (9, 18, 1 9 ,2 1 )

V. H ydrolytic M ethods (16, 26, 30, 45)

449

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 Vol. 14, No. 6

Fi g u r e 1. Fu r n a c e f o r Ha l o g e n De t e r m i n a t i o n

T he ob jective of the research w as the developm ent of a sim ple, rapid, and com plete procedure for converting all the halogens present in organic com pounds to halide ions in forms and environm ent perm itting their determ ination w ith a m inim um of further separation. Principal requirem ents were th a t the m ethod should serve for th e recovery of fluoride ion from stable organic fluoro com pounds and should perm it the determ ination of fluorine and other halogens in th e sam e sam ple.

P r in c ip le o f P r o p o se d M e th o d

T he results of exten sive prelim inary experim ents w ith th e more promising m ethods described in the literature indicate th a t th e m ost satisfactory m ethod is based upon fusion w ith a n alkali m etal. T he com pound to be analyzed is heated w ith m etallic sodium or potassium to a m oderately elevated tem perature in an evacuated sealed tube, yield ­

ing alkali halides in addition to the pyrolysis products, chiefly carbon, of the organic resi­

due. T he halide ion is then determ ined b y standard procedures. T h e m ethod d e­

scribed in detail below was evolved after m an y analyses of stable chlorofluoro com ­ pounds under a variety of conditions.

R e a g e n ts a n d A p p a r a tu s A saturated solution of lead chlorofluoride was prepared ¡is described by Scott (IS). All re­

agents were of the best obtainable grade and were tested for the presence of the halide ion being determined. It is particularly important to check the sodium and potassium metals for the halide ion being determined, and to use anhydrous ether.

The reaction tubes were made by drawing out the open ends of Pyrex ignition test tubes, 20 X 150 mm., and sealing on 12-cm. lengths of 10-mm. tubing. These reaction tubes may be used repeatedly, since there is little attack on the glass. T he ampoules prepared for sampling solids, liquids, and gases are described below.

Since a large number of determinations were to be run and the method was to be used for the

routine analysis of halogen compounds in this laboratory, a suit­

able furnace was designed. The furnace together with one of the reaction tubes is shown in Figure 1; an outline drawing is given in Figure 2. It may be constructed at a cost of about three dollars for material and the expenditure of 8 man-hours of labor.

Co n s t r u c t i o n o f Fu r n a c e. The furnace tubes are four iron pipes, 2.5 cm. (1 inch) in diameter and 30 cm. (12 inches) long, supported horizontally by the two 22.5-cm. (9-inch) paint-can lids which constitute the ends of the furnace. The tubes are arranged symmetrically on a circle of 3.25-cm. (1.5-inch) radius, with 2.5 cm. (1 inch) protruding at each end. The ends are threaded to take lock nuts and pipe couplings, into which are screwed the cast-iron closure plugs. Holes are drilled in the plugs to provide for release of pressure. A 9.375-mm. (0.375- mch) pipe through the center and paralleling the furnace tubes serves as a thermocouple well. The five tubes are wrapped as a unit with asbestos paper, and the unit is wound with 525 cm.

(17.5 feet) of N o. 23 Chromel wire having a resistance of 1.25 ohms per foot. The ends of the resistance wire terminate in a motor plug base set in one end of the furnace near the circum­

ference. The resistance winding is covered with several more layers of asbestos paper held in place with asbestos cord. The jacket of the furnace is a 25-cm. (10-inch) section of galvanized furnace pipe. Sil-O-Cel is used as insulation between the jacket and the asbestos-wrapped unit of five tubes. N o insulation was used between the furnace tubes themselves.

The furnace reaches 400° C. on the 110-volt line in 75 minutes, and is held at this temperature by an external resistance of 2 ohms in series with the furnace. The resistance, made by wind­

ing approximately 120 cm. (4 feet) of N o. 19 Chromel wire on a cone heater, is mounted on a switch box in parallel with a fuse, so that it may be shunted out simply by screwing in the fuse plug.

The furnace and external resistance are mounted on a board, the furnace resting in a cradle made of 12.5 X 3 mm. (0.5 X 0.12 inch) strap iron.

P r o c e d u r e fo r A n a ly sis

M ost of the com pounds analyzed were liquids and the pro­

cedure w as first developed for m aterial in th is state.

An a l y s i s o f Li q u i d s. Ampoules for sampling liquids are blown from 3-mm. Pyrex tubing, slightly drawn out. The bulbs are 6 to 8 mm. in diameter, with stems 5 to 6 cm. long; the suc­

cessive steps in their preparation are shown in Figure 3. A 0.10- to 0.15-gram sample of the liquid compound is drawn into the previously weighed ampoule, and the ampoule is sealed and weighed again. Care is taken to pyrolyze none of the compound during sealing. The ampoule containing the sample is placed in the reaction tube and 5 ml. of ether are added. The sodium or potassium metal is introduced in the form of very small pieces, the amount depending upon the size of sample taken and its halogen content (the optimum amount is usually 0.3 to 0.5 gram, giving several hundred per cent excess), and is weighed roughly or simply estimated. The reaction tube is then connected to an

Fu r n a c e Co n st r u ct/o n

A. F U S E ( S H U N T ) B. CONE R ESISTA N CE C. F U R N A C E TUBES D. T H E R M O C O U P L E

Vi E L L

INCHES

Fi g u r e 2 . Fu r n a c e f o r Ha l o g e n De t e r m i n a t i o n

June 15, 1942 A N A L Y T I C A L E D I T I O N 451 aspirator and all the ether is drawn off. The evacuation of the

reaction tube in this manner serves to remove oxygen and water vapor completely from the tube and to give a low pressure. Re­

moval of the oxygen and water vapor maintains the surface of the alkali metal clean, and therefore more reactive, and at the same time prevents attack of the reaction tube. Reduction of the pressure decreases the possibility of explosion of the tube when heated, and increases the vaporization of the compound and alkali metal, thus speeding up the reaction.

The stem of the reaction tube is sealed oil with a hand torch while the tube remains connected to the water aspirator. The reaction tube is most conveniently sealed off when supported in a vertical position by means of the rubber tubing from the aspira­

tor. It is obviously advisable to have a trap in the line to pre­

vent water being drawn into the reaction tube in case of a drop in the water pressure. After the reaction tube is sealed, the am­

poule is broken by shaking and the reaction tube placed in the furnace at 400° C. After 15 to 30 minutes, depending upon the compound being analyzed, the tube is removed and allowed to cool. It is then opened by breaking off the stem close to the original seal and the excess alkali metal is decomposed by the cautious addition of ethyl alcohol. The contents of the tube are transferred with several portions of wash water to a 100-ml.

beaker and the ampoule, including stem, is crushed. The broken glass, carbon, and any silica are then filtered off through a No. 4 Jena glass filtering funnel or crucible or equivalent Pyrex filter.

If the filter becomes clogged with carbon, it can be cleaned by immersion overnight in warm chromic acid-sulfuric acid solution.

The filtrate is neutralized with nitric acid and the halide de­

termined in the filtrate by standard methods. In this investiga­

tion, chloride, bromide, and iodide were determined gravimetri- cally by precipitation as the silver salts, and fluoride was deter­

mined by precipitation and weighing as lead chloroiluoride, using essentially the precipitation technique of Hawley (15). If compounds containing nitrogen are analyzed, the halide procedure used must avoid interference with cyanide ion; the latter does not interfere with the fluoride determination.

If the compound being analyzed contains fluorine and another halogen, both m ay be determined on the same sample, or a sepa­

rate sample may be used for each determination, the choice de­

pending upon the relative importance of rapidity and accuracy.

To determine both halogens from a single sample, aliquot parts of the fusion filtrate are taken.

An a l y s i s o f Low7 Me l t i n g So l i d s. Solids which have an appreciable vapor pressure at room temperature must be intro­

duced into the reaction tube in sealed ampoules to avoid loss dur­

ing evacuation of the tube. The ampoules for sampling solids are made from 10-cm. lengths of 6-mm. Pyrex tubmg, with a fragile bulb blown in one end (see Figure 3). After the ampoule has been weighed and the sample introduced, it is evacuated and sealed oil near the middle with a torch, care being taken to pyrolyze none of the compound. The two sections of the glass are weighed to give by difference the W'eight of sample contained in the sealed portion. The buoyancy effect of air on the weight of the ampoule is appreciable and a correction is calculated on the basis of the measured inside diameter and length. The correc­

tion is given by the formula, C = r-irld, where r is the internal radius of the ampoule in centimeters, I is the length of the sealed ampoule in centimeters, and d is the density of air in grams per cubic centimeter. The correction, C, is simply added to the ap­

parent weight of the sample. This correction assumes that the ampoule is completely evacuated; this, of course, is not true, but the false assumption simplifies calculation and introduces an error of considerably less than 0.1 mg.

The sealed ampoule containing the sample is placed in the re­

action tube, fragile end down, and the addition of ether and alkali metal and the evacuation and sealing-off are carried out as for liquids. The fragile end of the ampoule is then easily broken by shaking and the solid intimately mixed with the small pieces of alkali metal by rotating the reaction tube. The rest of the pro­

cedure is the same as for liquids, except that in removing the con­

tents of the reaction tube the ampoule is not crushed. It is easily and thoroughly cleaned by adding 5 ml. of distilled water to the reaction tube, bringing the water to boiling, and momen­

tarily removing the tube from the flame to allow the water to cool, thus drawing water into the ampoule. The water is again boiled, forcing it out of the ampoule, and poured into the beaker con- . taining the previous washings of the reaction tube. This proc­

ess is repeated several times.

An a l y s i s o p Ga s e s. Gases are cooled below their boiling points and the resulting liquids poured into ampoules made from 10-cm. lengths of 5-mm. Pyrex tubing. W ith the lower half of the ampoule immersed in the cooling bath, the open end is drawn out to a fragile tip and sealed. The ampoule is placed in the re­

action tube with the fragile tip downward, facilitating release of the sample when desired. Correction is made for the buoyancy

Fi g u r e 3 . St e p si n Co n s t r u c t i o n o f Am p o u l e sf o r Sa m p l i n o

effect of air. The analysis is carried out as for liquids, and the inside of the ampoule is rinsed as in the analysis of solids. The lowest boiling substance sampled by this method was dichloro- difluoromethane, boiling point —3 0° C.

C h o ic e o f D e c o m p o s it io n C o n d itio n s

M any organic halogen com pounds were analyzed using decom position tem peratures from 150° to 600° C., varying the tim e of heating from 15 m inutes to 2 hours, and using either sodium or potassium m etal. On the basis of these prelim inary investigations, th e standard procedure adopted for com pounds containing only chlorine, bromine, or iodine is fusion w ith sodium a t 40 0 ° C. for 15 m inutes.

Occasional low results w ere obtained w ith organic fluoro com pounds w ith th ese decom position conditions. As there is no apparent relation betw een th e ty p e of fluoro com pound and the discordant results, th e standard procedure adopted for fluoro com pounds is decom position w ith potassium m etal a t 4 0 0 ° C. for 30 m inutes. I t has been observed th a t potas­

sium m etal flows to coat th e reaction tube, giving a clean surface of considerable area, whereas sodium does not. T he higher cost of potassium am ounts to only about one cen t per determ ination.

6-Chlorocoum arin w as th e on ly com pound contain­

ing on ly chlorine, brom ine, or iodine for which con­

ditions other than heating to 40 0 ° C. for 15 m inutes with m etallic sodium had to be applied. T h e fusion filtrate was alw ays strongly colored, and the colored m atter precipitated upon acidification of th e fusion filtrate preparatory to precipi­

tation of th e chloride as silver chloride. U nder th e condi­

tions adopted as standard for fluorine com pounds, although the tem perature was inad verten tly run to 45 0 ° C., good re­

sults were obtained.

P r e s e n t a t io n o f D a ta

T able II gives th e data obtained in th e analysis of 24 or­

ganic halogen com pounds using the m ethod evolved in this investigation. All results obtained on every com pound whose analysis w as attem p ted by m eans of th e proposed m ethod are reported. T he m ean value and th e average de­

viation for the halogen con ten t of each of th e com pounds analyzed are given, together w ith th e number of determ ina­

tions upon w hich these values were based. Since work w as com pleted on th e developm ent of the procedure, a large num ­ ber of organic halogen com pounds have been successfully analyzed b y the m ethod.

Since th e procedure was developed prim arily to fill the need for a rapid and accurate m ethod for determ ining fluorine in organic com pounds being prepared in this laboratory, th e m ajority of com pounds analyzed were fluoro com pounds.

Several com pounds containing o n ly chlorine, bromine, or iodine were analyzed because it appeared th a t th e m ethod had certain advantages over th e procedures com m only em -