INDUSTRIAL a n d ENGINEERING CHEMISTRY
A N A L Y T IC A L E D I T I O N
HARRI SON E. HOWE, EDITOR » ISSUED MAY 15, 1940 m VOL. 1 2 , NO. 5 ♦ CONSECUTI VE NO. 10
De t e r m i n a t i o n o f Me t h y l p r o p e n e b y Me a n s o p a Mo d i f i e d De n i g é s Re a g e n t...
A. Newton and E. J. Buckler 251
F i l t e r Ai d s... Allen L. Olsen 254
De t e r m i n a t i o n o f Ce l l u l o s e i n Fi b r o u s Ag r i c u l t u r a l Wa s t e s...
J. D avid Reid, G. H. Nelson, and S. I. Aronovsky 255
Q u a n t i t a t i v e S p e c t r o c i i e m i c a l A n a l y s i s o f D i l u t e S o l u t i o n s ...A . E. Ruehle and E. K. Jaycox 260
Se p a r a t i o n a n d Ch a r a c t e r i z a t i o n o f Pe t r o l e u m Ac i d s...
H enry G. Schutze, Billie Shive, and H. L. Lochte 262
D e t e r m i n a t i o n o f S u l f a t e b y T e t r a h y d r o x y q u i n o n e M e t h o d ...H . Lewis Kahler 266
Ce r a t e Ox i d i m e t r y...
G. Frederick Smith, Gerald Frank, and A. E. K o tt 268
Si l i c o m o l y b d a t e Me t h o d f o r Si l i c a...
Harold W. Knudson, C. Juday, and V. W. Meloche 270
Qu a n t i t a t i v e De t e r m i n a t i o n o f In d o l e...
Lewis H. Chernoff 273
Pr e s s u r e Re g u l a t o r f o r Va c u u m Di s t i l l a t i o n . . .
Melvin S. Newman 274
So l u t i o n Me t h o d f o r Sp e c t r o g r a p i i i c An a l y s i s . . .
R. J. Keirs and D. T. Englis 275
Dr y Ic ea s a Pr e v e n t i v eo f At m o s p h e r i c Ox i d a t i o n .
George E. Ferguson and Leopold Scheflan 276
Ga g i n g Ad s o r p t i o n Po w e r o f Co l l o i d a l Fe r r i c Ox i d e b y Dy e Ad s o r p t i o n...
Frank H. Dottenveich w ith Wilbert J. Huff 277
R e m o v a l o f P h o s p h a t e s f r o m S o l u t i o n s o f H y d r o g e n P e r o x i d e ... S . R . Dickman and R . H . Bray 279
Co l o r i m e t r i c De t e r m i n a t i o n o f Le a d Ch r o m a t e b y Di p h e n y l c a r b a z i d e...
T. V. Letonoff and John G. Reinhold 280
Mo r t a r a n d Pe s t l e f o r Po w d e r i n g Gl a s s...
II. L. W underly 284
Id e n t if ic a t i o n o f 2 -Am i n o e t h a n o l . Bernhard Keiser 2 8 4 Im p r o v e d Mo b il o m e t e r f o r Me a s u r in g Co n s is t e n c y
o f Fl u i d a n d Se m i f l u i d Gr e a s e s...
K . C. Combes, C. S. Ford, and W. S. Schaer 285 Th e r m o e l e c t r ic Ab s o r p t i o m e t e r f o r An a l y t ic a l
Wo r k . . H obart H. Willard and Gilbert H. Ayres 2 8 7 Mo d i f i e d Ro i i r i g Ex t r a c t io n Tu b e ...
C. W. Sullens and W. Rankin 291 Au t o m a t ic Co n s t a n t Fl o w Re g u l a t o r f o r Lo w Ga s
Fl o w s... Leslie Silverman 292 La b o r a t o r y El e c t r ic St i r r i n g Mo t o r...
E. B. Hershberg 293 Th e r m o m e t e r f o r Lo w Te m p e r a t u r e s...
A. Farkas and L. Farkas 296 Mic r o c h e m is t r y:
Eq u iv a l e n t We i g h t s o f Sa l t so f Or g a n ic Ac id s . . K arl H . D ittm er and R. G. Gustavson 297 Bo m b f o r De t e r m i n i n g Or g a n ic Ch l o r i n e b y Lim e-
Fu s io n Me t h o d...
William M. M acNevin and William H. Baxley 299 Mic r o g r a v im e t r ic De t e r m in a t io n o f Ac t iv e Hy
d r o g e nb y Gr ig n a r d Re a g e n t...
R. N . Evans, J. E. Davenport, and A. J. Revukas 301 Se m im ic r o- Du m a s Me t h o df o r Di f f i c u l t Co m p o u n d s
Anthony R. Ronzio 303 Sy s t e m a t ic Qu a l it a t iv e Or g a n ic Mi c r o a n a l y s is .
H erbert K. Alber and J. T. B ryant 305 Im p r o v e m e n t o f Fo r m a l d o x im e Co l o r im e t r ic
Me t h o d f o r Ma n g a n e s e...C . P. Sideris 307 Mi c r o t it r a t io n o f Se l e n i u m...
G rant Wernimont and F. J. Hopkinson 308 De t e r m in a t io n o f Mi n u t e Am o u n t so f Po t a s s iu m .
Irving Allen K aye 310 Mo d e r n La b o r a t o r ie s:
Ne w Re s e a r c h La b o r a t o r y o f St a n d a r d Oi l Com p a n y o f Ca l i f o r n i a...R . A . Halloran 3 1 2
T h e A m erican C hem ical Society assum es no re sp o n sib ility fo r th e s ta te m e n ts a n d opinions a d v an c e d b y c o n trib u to rs to its p u b lic a tio n s.
22,800 copies of th is issue p rin te d . C o p y rig h t 1040 b y A m erican C h em ical S o ciety .
P u b l i c a t i o n O ffice : E a s t o n , P e n n a . E d i t o r i a l O ffice : R o o m 706, M ills B u ild in g , W a s h in g to n , D . C .
T e l e p h o n e : N a t i o n a l 0848. C a b l e : J i e c h e m ( W a s h in g to n )
P u b lish e d b y th e A m e ric a n C h em ical Society, P u b lic a 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 th e 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 c t of M arch 3, 1879, as 24 tim es a y e ar. I n d u s tria l E d itio n m o n th ly on th e 1st; A n a ly tic al E d itio n m o n th ly on th e 15 th . A ccep tan ce for m ailin g a t sp ecial r a te of p o stag e pro v id ed lo r in Sectio n 1103, A ct of O c to b er 3, 1917, a u th o riz e d J u ly 13, 1918.
A n n u a l s u b sc rip tio n r a te , In d u s t r i a l Ed i t i o n a n d An a l y t i c a l Ed i t i o n
sold o n ly as a u n it, $4.00. F oreign p o stag e to co u n tries n o t in th e P a n
A d v e rtis in g D e p a r t m e n t : 332 W e s t 4 2 n d S t r e e t , N ew Y o rk , N . Y . T e l e p h o n e : B r y a n t 9-4430
A m erican U n io n , $2.25; C a n a d ia n p o stag e, $0.75. Single 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. S p ecial ra te s to m em bers.
N o claim s c an be allow ed fo r oopies of jo u rn a ls lo st in th e m ails unless su ch claim s a re receiv ed w ith in 60 d a y s of th e d a te of issue, a n d n o olaim s w ill be allow ed fo r issues lo s t as a re s u lt of in sufficient n o tice of c h an g e of a d d ress. (T en d a y s ’ a d v a n c e n o tice re q u ire d .) " M iss in g fro m files”
c a n n o t b e acc e p te d as th e re a so n for h o n o rin g a claim . C h arle s L. P a rso n s, B usiness M an ag er, M ills B u ild in g , W a sh in g to n , D . C ., U . S. A.
4 IN D U STR IA L AND E N G IN E E R IN G CH EM ISTR Y VOL. 12, NO. 5
c lc °.
T h e O rig in a to rs a n d D e sig n e rs of th e C o m p act C o m b in a
tio n U n it a n d th e C lo sed E jec to r F u m e D isp o -
s a l S y s t e m
(P a te n te d ).
KJELDAHL NITROGEN APPARATUS
a n d
A sso c ia te d A p p aratu s and L ab oratory T a b les
ßettesi Jßcduvuitosiif, ^auip^meni
A H IG H LY E F F IC IE N T AND P A T E N T ED F U M E DISPOSAL SYSTEM ALONG W IT H D U R A B ILITY AND CLEANLINESS IS AN EX CLU SIV E F EA TU R E OF OUR K JELD A H L N IT R O G E N APPARATUS.
EACH CO M PO NEN T PA R T OF GAS OR ELECTRICA LLY E Q U IP
P E D U N ITS IS D ESIG N E D AND BU ILT INTO OUR M O D ER N E Q U IP M E N T TO OBTAIN T H E E F F IC IE N C Y , D U R A B ILITY AND EASE OF O PER ATIO N SO NECESSARY IN APPARATUS TH A T R EC EIV ES HARD USAGE.
W E KNOW OF NO B E T T E R REC O M M EN D A TIO N OF S U P E R IO R IT Y A N D V A L U E TH A N OUR P R E D O M IN A N T LIST OF USERS COVER
IN G A D IV E R S IF IE D F IE L D OF IND U STR Y.
Combination units in capacities 6 to 24.
Separate digestion units in capacities 6 to 96.
Separate distillation units in capacities 6 to 45.
MANY U N IQ U E A RR AN G EM ENTS A R E AVAILABLE AND W E O FF E R FULL COOPERATION ON OUR D IF F E R E N T A RRAN G E
M EN TS AND CAPACITIES AS T H EY APPLY TO YOUR USE AND SPACE ALLOTTED.
4 4 a F u r th e r in fo rm a tio n is a v a ila b le in o u r ♦ ♦ ♦ +T+ +T+ catalo g . D e ta ile d sp ecifica tio n s o n y o u r
♦ ♦ ♦ specific re q u ire m e n ts w ill b e s e n t w ith - ♦ ♦ ♦ o u t o b lig a tio n to you.
Fat and Fiber Apparatus
Y o u r i n q u ir y is in v it e d . N o tr o u b le t o s u b m i t p r o p o s a ls on y o u r r e q u ir e m e n ts a n d , o f c o u rs e , w i t h o u t o b lig a tio n to y o u .
Catalog on Request
M A N U F A C T U R E D A N D S O L D D I R E C T T O T H E U S E R B Y
LABORATORY CONSTRUCTION COM PANY, INC.
1 1 1 3 - 1 1 1 5 H olm es S t r e e t ...K an sas City, M issouri, U .S.A .
“ G O LD FISCH ” EX TR A C TO R A radically improved ether extraction appa
ratus th a t permits a material saving of tim e on control work and will be found most flexible for research work.
C R U DE F IB E R CO N D ENSER An apparatus th a t will m aintain a constant volume of solution and reduce frothing to a minimum. No metal parts are in contact with the solution. R u b ber hose connections are eliminated.
S how n w ith 3 I lc a t S w itch e s
12 fla sk capacity com bination u n it electrically equipped with three-heat switches, arranged distilla tio n decked over digestion.
T h r e e -h e a t sw itc h e s a t a m o d e ra te in c re a s e in c o st a re av ailab le w ith w a tta g e s to s u it y o u r p a rtic u la r d e te rm in a tio n s .
MAY 15, 1940 ANALYTICAL E D IT IO N 5
SO DIUM O XALATE
P r i m a r y S t a n d a r d Na,C,0«
A N A LYTICA L R E A « * *
P O IS O N
«c h r o d t Ch e m ic a ly;
y mqwi«cal rwi*eu22^e
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 • Chicago • Philadelphia • N ew York
PRECISION ^—
. . . . i n t h e L A B O R A T O R Y
A ccurately m easuring laboratory app aratu s is of little value in analytical procedure unless th e chemicals employed are free from im purities giving rise to erroneous results. M allinckrodt A nalytical R eagents—each scrupulously refined to m eet predeterm ined s ta n d ards of p u rity —are especially designed to facilitate analytical p re
cision. Chemists can depend upon M allinckrodt A. R. Chemicals because they conform to A. C. S. specifications.
S e n d for n ew catalogue o f a n a l y t i c a l r e a g e n ts a n d o t h e r c h e m ic a ls fo r l a b o r a t o r y u s e . I t c o n t a in s d e s c r ip tio n s o f c h e m i
c a ls s u it a b le fo r e v e r y t y p e o f a n a ly ti c a l w o rk . . . g r a v i m e tr ic , g a s o m e tric , c o lo r im e tr ic o r t i t r i m e t r i c .
IN D U STR IA L AND E N G IN E E R IN G CH EM ISTR Y VOL. 12, NO. 5
WHICH WAX WOULD YOU USE?
Diffraction pattern of wax ‘'X ” Diffraction pattern of paper prepared with wax “ X ”
Wax “X ” and wax “Y ” seemed to have the same characteristics. Yet, when these two waxes were used in the m anufacture of wax paper—using the same paper stock—the re
sulting product was acceptable with wax “X ” and sub-standard with wax “Y ” .
This is only one of the m any wax problems th a t can be solved by an x-ray crystal analy
sis with the G-E X R D Unit. You, too, m ay have a problem which can best be solved by x-ray diffraction. One good way to be sure is to consult w ith our diffraction laboratory
staff, and write for your copy of the interesting catalog which describes and illustrates the G-E X -R ay Diffraction Unit. I t also in
cludes much valuable information about the applications of this modern, time-saving, fact
finding method. Address your request to D epartm ent 195.
G ENERA L @ ELECTRIC X -R A Y 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 , ILL ., U. S. A .
Diffraction pattern of wax “ Y ” Diffraction pattern of paper prepared with wax “ Y ”
MAY 15, 1940 ANALYTICAL E D IT IO N 7
No. 28010
KIMBLE GLASS COMPANY • • • • v i n e l a n d , n . j .
N E W Y O R K • • C H I C A G O • • P H I L A D E L P H I A • • D E T R O I T • • B O S T O N No. 20040-ST
No. 20030
No. 28015-ST \ - fÂ Ë No. 37000
No. 17030- S T
K i m e i E
O F
A C C U R A C Y
Every p ie c e o f B lu e L in e
< e x a x>G la ssw a re is IN D I
VIDUALLY RETESTED to rig id to le r a n c e s — o n e o f th e o u t s t a n d in g r e a so n s fo r t h e BLUE L IN E ’S p o s it io n as th e la b o ra to ry sta n d a r d FO R A SSUR A N C E.
B L U E T H E P I O N E E R O F
L I N E
97ze V i s i b l e G u a r a n t e e o f
C O L O R E D C A L I B R A T I O N S
STOCKED BY LEADING LABORATORY SUPPLY HOUSES THROUGHOUT THE UNITED STATES A N D C A N A D A
© 1940, KIMBLE G U S S CO.
I n v i s i b l e Q u a l i t y ♦ • »
8 IN D U STR IA L AND E N G IN E E R IN G C H EM ISTR Y YOL. 12, NO. 5
Low first cost, economy of operation, simplicity of control, wide range of temperature settings, beauty and utility combine to make the new Cenco-deKhotinsky Oven a desirable and inexpensive addition to the equipment of any laboratory requiring a space in which accurate tem
perature control is achieved.
Its temperature range is from that of the room to approximately 210 degrees centigrade above surrounding temperature. I t can therefore be used as an incubator, a drying oven, a sterilizer, or as a baking oven for varnishes, lacquers and japans, as well as for curing synthetic
Temperature constancy and uniformity in the oven chamber are ex
cellent. Departure from average temperature at any point in the operating range is within one degree centigrade. The temperature control unit, which is of utmost simplicity, is independent, both struc
turally and functionally, of the oven chamber; but the expansible element is located wholly within the chamber, with the result that it responds quickly to temperature changes. No relay is employed.
The heating current is turned on and off automatically by means of a snap-action control switch.
The oven chamber is so well insulated that at maximum temperature the input is only 400 watts—about 40% less than that required for an electric toaster or flatiron. The heating units operate considerably below incandescence, and are not exposed to the air in the oven cham
ber; and the switching and control mechanisms are entirely removed from the chamber. Without change in heating units, the oven may be operated on either 115 or 230 volts A.C., merely by throwing a switch.
The external housing is made of metal and finished with aluminum
“shrivel” finish. The design is modern, with chromium-plated hinges and latch.
★ 9 5 0 5 0 A C E N C O - d e K H O T I N S K Y C Y L I N D R I C A L C H A M B E R D R Y I N G O V E N $ 8 5 .0 0
C H IC A G O 1 7 0 0 Irving Pk. Blvd.
Lakeview Station
S C I E N T I F I C INSTRUMENTS
N e w York • Boston •
*
C H I C A G O
L A B O R A T O R Y A P P A R A T U S
• Toronto • San Francisco
B O S T O N 7 9 Amherst St.
Cambridge A Station
(Hue IN A NEW CONSTANT TEMPERATURE DRYING OVEN
MAY 15, 1940 ANALYTICAL E D IT IO N 9
means
Research in Glass
On the Silver/M iniversary of "PYREX" Laboratory W are
T H E N E W E S T A C H I E V E M E N T I N G L A S S M A K I N G
“ P Y R E X V Y C O R ” L ab o rato ry G lassware is an im por
ta n t supplem ent to th e “ P Y R E X ” line. I t in no w ay dis
places laboratory ware fabricated from sta n d a rd P Y R E X b ran d Chem ical Glass (coefficient o f expansion .0000032) w hich, over th e p a s t q u a rte r of a cen tu ry has proved em inently satisfactory for m ost lab o rato ry usage.
A lim ited num ber o f laboratory item s in th e new H igh Silica glass will soon be available th rough yo u r regular lab o rato ry supply dealer. These item s, together w ith a s ta te m e n t of th e properties of th e glass, will be described in a catalog supplem ent now in preparation.
K indly use coupon below.
1 w e n t y - f i v e y e a r s a fte r the introduction of P Y R E X b ran d C hem ical Glass, Corning Research is able to a n n o u n c e a n e v e n g r e a te r d e v e lo p m e n t— “ P Y R E X V Y C O R ” H igh Silica Glass, No. 790.
T his new ultra-low -expansion glass has a linear coeffi
cient o f .0000008— th e lowest of an y com m ercial glass o th e r th a n fused silica. Its developm ent necessitated a new an d rev olutionary technique in glass m aking—th e first real d ep a rtu re from th a t ancient a r t in 4000 years.
T h e distinguishing properties of this new glass—excep
tional stability, high softening point an d very low therm al expansion— m ake laboratory ware fabricated from it ideal for m a n y applications. F o r high tem p eratu re reactions, rap id chem ical analyses or an y exceptionally accurate work, th is new H igh Silica glassware will be m ost useful.
P Y R E X " is a registered trade-m ark an d indicates m anufacture by
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 . Y,
CO R NIN G GLASS W ORKS * C o rn in g , N. Y ., D e p t. LW -7 Please send com plete inform ation on th e new “ P Y R E X V Y C O R ’ L ab o rato ry Glassware.
T H E ÎY E W W A I t E C A N B E I D E N T I F I E D B Y
T H I S M A R K
Name.
P L E A S E P R IN T
Address.
‘VYCOR” is a trade-mark of
Corning Glass W'orks Laboratory
.Supply Dealer.
Position
i
10 IN D U STR IA L AND E N G IN E E R IN G CH EM ISTR Y VOL. 12, NO. 5
K L E T T -S U M M E R S O N
P H O T O E L E C T R IC C O L O R IM E T E R S
T E S T T U B E M O D E L and N E W , GLASS C E L L M O D E L
3788-A 3790-A
C O L O R I M E T E R , P H O T O E L E C T R I C ( P h o to e le c tr ic P h o t o m e t e r ) , K l e t t - S u m m e r s o n . D e s ig n e d b y D r . W . H . S u m m e rs o n , o f C o rn e ll U n iv e r s it y M e d ic a l C o lleg e. S ee T h e J o u r n a l o f B io logical C h e m is t r y , Vol. 130, N o . 1 (Septem ber, 1939), p. 149.
A self-contained, portable instrum ent of simple and rugged construction, with built-in galvanometer. Measurements can be made w ith ease and rapidity, all necessary adjustm ents being controlled by a single knob, with only a few seconds re
quired for each measurement. The zero point does n ot shift and results are unfailingly reproducible.
The compensated electrical circuit is based on the double photoelectric cell null-point principle, giving colorimetric meas
urements in term s of the graduations on a precision potentiometer. The light source consists of a 100-watt lamp which can be operated from any convenient electric outlet, a.c or d.c., no constant current device being required since ordinary fluctuation in the line voltage or light intensity does n ot affect the readings.
The instrum ent is provided w ith a logarithmic scale, reading from 0 to 1000, so graduated th a t concentration of unknown solutions is obtained directly by multiplying the scale reading by th e proper factor, predetermined from a standard.
Plotting of calibration curves or the use of logarithm tables is therefore unnecessary for solutions obeying Beer’s law.
T he inherent precision of measurements is approxim ately 1/ s of 1 % of a full linear scale length.
T e s t T u b e M o d el. S ta n d a rd iz e d te a t tu b e s 12.5 m m d ia m e te r a re u sed as c o n ta in e rs fo r th e so lu tio n s, o n ly 5 m l of w hich is re q u ire d for a re a d in g . M icro tu b e fo r 1 m l of fluid is also a v a ila b le . T e s t tu b e s a re in ex p en siv e, c o n v e n ie n t t o u se. easy to clean, a n d p e rm it ra p id re a d in g s w hen th e u n k n o w n so lu tio n s a re p la c ed in s e p a ra te tu b e s. T h e y c an b e c en trifu g e d o r h e a te d , if n ecessary . G la ss Cell M o d el. M e a s u re m e n ts a rc m a d e in fused glass cells w ith so lu tio n d e p th s of 2.5, 10, 20 or 40 m m , p e rm ittin g p h o to e le ctric
m e a su re m e n ts o v e r a w ide ra n g e of colored or tu rb id so lu tio n s. A n a d a p te r , fo r in se rtio n in th e cell c h am b er, p ro v id e s fo r th e use of s ta n d a r d 12.5 m m te s t tu b e s.
A filter frame, which takes any standard light filter 2 inches square, is offered as an accessory for use with either Model.
This Colorimeter is suitable for practically any procedure which has been devised for the visual colorimeter.
C ode
3788-A. Colorimeter, Photoelectric, K lett-Sum m erson T est Tube Model, as above described, complete with two Word color filters in separate holders, i.e. 5400A and 4200A, built-in galvanometer, heat filter, two standardized test tubes, 100-w att lamp, and booklet of instructions for use and methods for fourteen standard bio
chemical procedures. For 110 volts, a.c. or d.c... 148.00 Dyjac
3 788-D 5. M icro T u b e , for 1 m l of fluid; fo r in se rtio n in sp rin g h o ld e r in p la c e of 12.5 ram s ta n d a rd t u b e ...1.20 D y ja h m
3790-A. Colorimeter, Photoelectric, K lett-Sum m erson Glass Cell Model, w ith two color filters, i.e. 5400A and 4200A, built-in galvanometer, heat filter, 100-watt lamp, and fused glass cell for 20 mm and 40 mm solution depth, but w ithout test tube adapter. For 110 volts, a.c. or d.c... 183.00 Dyjbe
3790-J . A d a p ter, fo r in se rtio n in th e cell c h a m b e r of 3790-A to a d a p t i t fo r use w ith s ta n d a r d 12.5 m m te s t t u b e s ... 8.00 D yjbt 3788-1. F ilte r F ra m e , on ly , fo r h o ld in g a n y s ta n d a rd lig h t filter 2 in ch es sq u a re . F o r use w ith e ith e r M o d e l... 2.80 D yjal 3 790-F . G lass C ell, w ith p la n e , p a ra lle l sides fu sed to g e th e r, fo r 20 m m s o lu tio n d e p th or, w hen u sed endw ise, fo r 40 m m so lu tio n d e p th
... 5.80 D yjbo
A R TH U R H. T H O M A S C O M P A N Y
R E T A l L— W H O L E S A L E — E X P O R T
LABORATORY APPARATUS AND REAGENTS
WEST WASHINGTON SQUARE, PHILADELPHIA, 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 and 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 BY 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
Determ ination o f M ethylpropene
B y M eans o f a M odified D en ig es R eagen t
A . N EW TON A N D E. J . BU C KLER, T rin id a d L easeholds, L td ., P o in tc -a -P ie rre , T rin id a d , B. W. I.
T h e d e t e r m in a t io n o f m e t h y lp r o p e n e b y m e a n s o f D e n ig e s r e a g e n t is c o m p lic a te d b y t h e s o lu b ilit y o f t h e p r e c ip it a t e i n n it r ic a c id a n d t h e c h a n g e i n w e ig h t a n d c o m p o s i t i o n o f t h e p r e c ip it a t e o n w a s h in g w it h w a te r . T h e fir s t s o u r c e o f error is e l i m i n a t e d b y u s in g a n e u t r a liz e d D e n ig e s r e a g e n t . T h e s e c o n d is a v o id e d b y u s in g as t h e m e a s u r e o f m e t h y lp r o p e n e a b so r b e d n o t t h e w e ig h t o f t h e p r e c ip it a t e b u t t h e w e ig h t o f m e r c u r y i n t h e p r e c ip it a t e , w h ic h is c o n s t a n t u n d e r t h e c o n d it io n s o f t h e d e t e r m in a t io n a n d a m o u n t s t o s e v e n a t o m s fo r e a c h m o le c u le o f m e t h y lp r o p e n e u s e d . U n d e r t h e s e c o n d it io n s t h e m e t h o d is a c c u r a t e a n d r e a s o n a b ly ra p id .
T
W O m ethods are a t present available for th e determ inatio n of m ethylpropene, using sulfuric acid (4) and h y drogen chloride (3), respectively.
L ittle a tte n tio n appears to have been paid to th e ability o f m ethylpropene to form a p recipitate w ith solutions of m ercuric n itra te as originally reported by Deniges (J), possibly because th e scan ty inform ation in th e literatu re im
plies th a t th e precip itate is of variable composition.
Deniges used a solution prepared by adding 20 grams of mer
curic oxide to 100 ml. of w ater and 40 ml. of 75 per cent nitric acid, heating to dissolve the mercuric oxide, and then diluting with 400 ml. of water. After methylpropene was absorbed in this solution th e product was boiled and an orange precipitate ob
tained which was stated to have the composition HgNOj.GiH».- Hg,NOa, corresponding to a content of 76.96 per cent of mercury and 7.18 per cent of C JIj. H urd and Goldsby (£), using the same solution, obtained 2.90 and 2.52 grams of precipitate from 0.13 and 0.115 gram of methylpropene, corresponding to a content of 4.48 and 4.56 per cent of methylpropene, respectively.
E x p e r im e n ta l
In prelim inary te sts to exam ine th e possibility of using th e reactio n w ith m ercuric n itra te for th e estim ation of m ethylpropene, sam ples of th e addition com pound were pre
p are d from th e p ure gas by th e procedure specified b y Deniges.
I n four d eterm inations th e results corresponded to 4.62, 3.65,
4.02, an d 3.47 p er cen t by w eight of m ethylpropene in th e precipitate. I t w as observed, however, t h a t th e filtrates often deposited additional solid on sta n d in g or on d ilution w ith w ater, an d it w as suspected th a t th e v a ria tio n in results was due to incom plete p recipitation in th e presence of n itric acid.
W hen th e p rec ip ita te was stirred w ith d ilute n itric acid, no ap p a ren t decom position occurred a t room te m p eratu re s b u t opalescent solutions were form ed from w hich solid could be reprecipitated by dilution or neutralization. T h e solubility of th e ad d itio n com pound in different stren g th s of n itric acid w as determ ined by preparing suitable m ixtures, filtering, and titra tin g m ercury in th e filtrates w ith sta n d a rd potassium thiocyanate. T h e results are recorded in F igure 1.
Deniges reagent contains ab o u t 80 gram s of n itric acid per lite r and, as will be shown la ter, th is concentration increases during reaction w ith m ethylpropene. T h u s th e reag en t will reta in in solution a t least 0.11 gram of th e p rec ip ita te per lite r and, ta k in g into consideration th e nitric acid form ed in th e reaction, th e am o u n t retain ed will be d ependent on th e ratio of th e volum e of m ethylpropene to th e volum e of reagent used.
Fi g u r e 1. So l u b i l i t y o f Pr e c i p i t a t e i n Ni t r i c Ac i d
251
252 IN D U STR IA L AND E N G IN E E R IN G C H EM ISTR Y
Fig u r e 2 . Ap p a r a t u sf o r De t e r m i n a t i o n o f Me r c u r y- Me t h y l p r o p e n e Ra t io
T h e au th o rs believe th a t th is circum stance accounts in p a r t for th e a p p a re n t differences in th e com position of th e pre
cip itate as calculated from th e results of previous w orkers.
In view of th e above results th e possibility of using a neutralized Denig&s reagent, prepared b y adding caustic soda solution to th e acid reagent u n til basic m ercuric n itra te began to p recipitate, was investigated. T h is solution w as found to absorb m ethylpropene rap id ly b u t in c o n tra st to th e acid reag en t no precip itate w as form ed in th e cold. P re cip itatio n took place on w arm ing to te m p eratu re s above 70° C. or could be induced b y adding a few drops of 75 per cen t n itric acid to th e cold solution and was accom panied b y an appreciable fall in pH . N o precipitation took place, even on boiling in a solu
tion buffered to p H 5.4 w ith sodium a c e ta te -a c e tic acid.
I t appears th a t th e reaction betw een m ethylpropene and m ercuric n itra te solutions ta k e s place in tw o stages. I n th e first stage m ethylpropene is absorbed w ith form ation of a solu
ble complex and liberation of hydrogen ions. I n th e second stage, w hich does n o t ta k e place above a critical p H value, th e insoluble complex is form ed.
C o m p o s it io n o f P r e c ip it a t e
Methylpropene, prepared by th e dehydration of pure trim ethyl carbinol and fractionation of the product, was absorbed in the neutralized mercuric nitrate reagent. The precipitate was filtered, washed w ith distilled water, and dried in vacuo over cal
cium chloride. M ercury was determined in this precipitate by dissolving in hot 70 per cent nitric acid, titra tin g w ith thiocya- n ate solution ((?), and precipitating as mercuric sulfide (7) or by th e pyridine-dichromate method (5).
Ta b l e I . Ef f e c t o f Wa t e r- Wa s h in g o n Me t h y l p r o p e n e- Me r c u r i c Ni t r a t e Pr e c i p i t a t e
N o. of W eig h t of H g C o n te n t
W eig h t of M e rc u ry in R esid u e from P p t. T a k e n W ashes R esid u e of R esid u e 1 00 -G ram P p t.
Qrams G ram s % Grams
3 7 7 .6 7 7 .6
4 .’8903 8 4 !8 0 2 3 7 8 .9 7 7 .5
4 .0 2 1 6 18 3 .9 0 5 0 7 9 .9 7 7 .6
3 .0 S 3 7 28 2 .9 7 8 9 8 0 .1 77 A
D eterm inations of th e m ercury co n ten t of th e p rec ip ita te gave concordant results b y th e th ree m ethods, b u t specim ens of th e p rec ip ita te prepared a t different tim es showed m ercury co n ten ts vary in g from a b o u t 78 to 82 p er cent. T h is v aria tio n w as traced to th e w ater-w ashing of th e precipitate. As shown in T able I, w ashing th e precip itate w ith successive 20-ml.
portions of w ate r a t room te m p eratu re (30° C.) decreased th e
w eight of th e precip itate b u t did n o t affect th e w eight of m ercury in it. N itra te could be de
tected in th e w ash w ate r a fte r all soluble m er
cury had been rem oved.
T h e change in w eight appears to be due to a replacem ent of n itra te groups in th e precip itate b y hydroxyl or possibly w ater. I t also appears th a t th is replacem ent is reversible.
C om bustion and gravim etric analysis showed th a t a p ro d u ct prepared, using th e neutralized reagent w ith th e m inim um of w ater-w ashing an d containing 78.3 p er cen t of m ercury, h ad a com position corresponding closely to 1 C^Ha (3.13 per cent b y w eight), 7 H g, 3 N 0 3, 2 H , and b y difference 9 0 , th e a p p a re n t m olecular w eight being 1793.
W hen a sam ple of th e precip itate w as boiled for 30 m inutes w ith a large q u a n tity of distilled w ater, a loss in w eight of 7.8 p er cen t resulted an d th e recovered precip itate contained 80.8 per cen t of m ercury corresponding to 74.4 gram s of m ercury p er 100 gram s of original p recipitate. T h is appreciable loss of m ercury w as accom
panied b y a change in color of th e p rec ip ita te from orange to deep red, and unlike th e p roducts obtained b y w ater-w ashing a t room te m p eratu re, th e color did n o t re v e rt to lig h t orange in c o n tac t w ith n itric acid.
I t is concluded from these results th a t th e to ta l w eight of p rec ip ita te obtained is n o t a satisfactory m easure of th e a m o u n t of m ethylpropene used. I t appears, however, th a t th e ratio of m ethylpropene used to m ercury in th e p rec ip ita te is constant.
VOL. 12, NO. 5
Ta b l e I I . Ra t io o f Me r c u r yi n Pr e c i p i t a t e t o Me t h y l p r o p e n e Us e d
V olum e of M e th y l
p ro p e n e T e m p . P ressu re
W eig h t of M e th y l
p ro p en e
W eig h t of M e rc u ry
A to m s of H g p er M ole of M e th y l
p ro p e n e
M l. 0 C. M m . Ho Gram Gram
12 .5 2 2 9 .5 7 5 8 .3 0 .0 2 8 2 3 0 .7 0 0 4 6 .9 4
12 .5 2 3 1 .0 7 5 8 .5 0 .0 2 8 1 1 0 .6 9 5 2 6 .9 2
12 .5 2 3 0 .0 7 5 8 .0 0 .0 2 8 1 8 0 .7 0 1 1 6 .9 6
M e r c u r y - M e t h y l p r o p e n e R a t i o . T h e a p p a ra tu s shown in F igure 2 w as used for determ ining th e ratio of m ercury to m ethylpropene in th e precip itate.
A sample of pure methylpropene was passed from reservoir D through stopcock W and drying tube C, containing calcium chlo
ride, into bulb P, fitted w ith mercury leveling bulb A . I ts pres
sure was adjusted to atmospheric by escape of excess gas through W and w ater seal B. After its tem perature and pressure had been recorded, th e sample was transferred from P to reaction bulb R , which had previously been charged w ith a suitable volume of neutralized reagent and evacuated. R was detached a t F and shaken vigorously for 10 minutes, air being adm itted through F to sweep methylpropene from th e capillary tubing. Finally, R was detached a t H , and the solution was washed into a beaker, heated to boiling, cooled to room tem perature, and filtered through a sinterea-glass crucible. After being washed w ith cold distilled w ater until the filtrate gave a negative te st for m ercury w ith ammonium sulfide, th e precipitate was dissolved in 7 0 per cent nitric acid, and th e mercury was determined w ith thiocya- nate.
T h e d a ta for th ree such determ in atio n s given in T ab le I I indicate th a t seven atom s of m ercury are present for each molecule of m ethylpropene in th e p recipitate.
R e a g e n t s
Me r c u r i c Ni t r a t e Re a g e n t. One hundred grams of pure mercuric oxide are mixed to a paste w ith about 100 ml. of distilled w ater and then dissolved in th e minimum quantity of 7 0 per cent
MAY 15, 1940 ANALYTICAL E D IT IO N 253
Q
Fi g u r e 3 . Ap p a r a t u s f o r Ro u t in e De t e r m i n a t i o n o f Me t h y l p r o p e n e i n
Ga s e s
nitric acid (about 90 ml.). About 10 grams of pure sodium hydroxide are dissolved in 15 ml. of water and the solution is added drop by drop to th e mercuric nitrate solution until a faint b u t perm anent white cloud of basic mercuric nitrate is produced.
G reat care m ust be taken not to add any appreciable excess of sodium hydroxide. The solution is diluted to 2 liters w ith distilled water, filtered, and stored in a dark, glass-stoppered bottle.
Po t a s s iu m Th io c y a n a t e. I t is convenient to use a solution about 0.07 N in potassium thiocyanate, which is prepared by dissolving 15 grams of the pure salt in distilled water and diluting to 2 liters. The solution is standardized against 0.2 to 0.3 gram of pure m ercury dissolved in 5 ml. of 70 per cent nitric acid.
A p p a r a tu s a n d P r o c e d u r e
Ap p a r a t u s. A convenient form of apparatus for the routine determ ination of methylpropene in refinery gases is shown in Figure 3 and consists of a water-jacketed gas buret, B, a com
pensator, L , and an absorption tube, S.
Pr o c e d u r e. About 1 ml. of w ater is drawn into the buret.
The gas sample, varying from 35 ml. for 20 per cent m ethylpro
pene to 150 ml. for 1 per cent methylpropene, is drawn into the buret, and after standing for about 30 seconds its volume and pressure are recorded. Into the absorption tube, S, are drawn about 50 ml. of neutralized reagent and the tube is then evacuated by a good w ater pump, closed, and attached to the apparatus.
The gas sample is transferred to the absorption tube, using the w ater to drive the gas through the connecting capillary tube, and taking care th a t no mercury is allowed to pass into the absorp
tion tube. After closing th e upper stopcock, R, the absorption tube is detached from the apparatus and shaken for 5 minutes and for a further 2 minutes after adm itting air.
T he liquid in the absorption tube is allowed to run into a 250-ml. beaker and the tube is washed out two or three times.
T h e beaker is heated gently to 100° C. (but not boiled), and
allowed to cool almost to room tem perature, and the liquid is filtered through a No. 4 sintered-glass crucible. (A No. 3 crucible is more rapid and usually satisfactory b u t occasionally allows some precipitate to pass.) Washing of the beaker and the crucible is carried out with cold distilled w ater until the filtrate gives no precipitate with ammonium sulfide, after which th e crucible is returned to the beaker and the precipitate dissolved by heating gently with about 10 ml. of 70 per cent nitric acid. When solu
tion is complete, the crucible is washed and removed.
The solution in th e beaker is oxidized to convert H g+ to H g++
by the dropwise addition of saturated perm anganate until the pink color persists and the excess of perm anganate is destroyed by th e addition of a very slight excess of 10 per cent oxalic acid solution.
After diluting to 100 to 150 ml., 2 ml. of saturated iron alum solu
tion in 50 per cent nitric acid are added and the solution is titra ted with standard potassium thiocyanate solution. One milliliter of 0.1 N potassium thiocyanate is equivalent to 0.01003 gram of mercury or 0.1C01 ml. of methylpropene a t 0° C. and 760 mm.
T i m e R e q u i r e d f o r A b s o r p t i o n . T o determ ine th e tim e required for th e absorption of m ethylpropene, a n um ber of analyses were carried o u t on a refinery Cj fraction containing 0.67 per cent of m ethylpropene, using approxim ately th e sam e volum e of gas and th e sam e volum e (50 ml.) of reagent b u t different tim es of shaking. T h e results are given in T ab le I I I . Ta b l e I II . Ef f e c t o f Tim e o f Sh a k in g o n Ab s o r p t i o n o f
Me t h y l p r o p e n e
V olum e of D ry T im e of M e th y lp ro p e n e
G as (S. T . P.) Sh ak in g H g in P p t. E x tra c te d
M l. M in . Gram %
1G5.1 7 0 .0 6 9 6 100
146 .7 1 0 .0 6 0 8 9 8 .2
161.4 0 .5 0 .0 6 4 2 9 4 .2
15 1 .9 0 .5 ° 0 .0 5 8 3 9 0 .4
° G as a d m itte d to a b so rp tio n vessel a n d th e n re m o v ed . N o s h ak in g .
All b u t th e la st traces of m ethylpropene are rem oved afte r shaking for 1 m in u te and 5 m inutes are ad e q u ate for com plete extraction.
V o l u m e o f R e a g e n t . A refinery C< fraction containing 19.73 p er cen t of m ethylpropene was used in each of a num ber of determ inations w ith different volum es of reag en t an d a co n stan t shaking tim e of 5 m inutes. T h e results are recorded in T able IV.
Ta b l e I V . Ef f e c t o f Vo l u m eo f Re a g e n t o n Ab s o r p t i o n o f Me t h y l p r o p e n e
V olum e of D ry
G as (S. T . P .) V olum e of
R e a g e n t H g in P p t. M e th y lp ro p e n e E x tra c te d
M l. M l. Gram %
4 1 .9 10 0 .2 0 7 0 4 0 .0
3 9 .6 25 0 .4 4 8 3 9 1 .5
4 1 .9 50 0.4 9 8 1 9 6 .4
4 0 .4 100 0 .4 9 9 2 9 9 .9
3 9 .8 200 0 .4 9 2 7 1 0 0 .0
T h e m ethylpropene present in the volum e of gas ta k en w as sufficient to com bine w ith all th e m ercury in 10 m l. of reagent.
Good results are obtained by using a volum e of reagent equal to ab o u t te n tim es th e volum e of m ethylpropene to be ab sorbed.
O t h e r G a s e s . E th en e, propene, an d 1,3-butadiene were slowly absorbed b y th e reagent b u t gave no p rec ip ita te when th e solution was boiled.
A m ixture of 1- and 2-butenes p repared b y th e d ehydration of sec-butanol w as slowly absorbed by th e reag en t and on w arm ing a fa in t yellow tu rb id ity was produced, th e m ercury co n ten t of th e precip itate corresponding to 0.37 per cen t of m ethylpropene in th e gas. T h e gas w as shaken w ith 67 p er cent sulfuric acid u n til one th ird of its volum e h ad been absorbed, w hen th e residue gave a b arely d etectable opales
cence w ith m ercuric n itra te reagent, corresponding to less th a n 0.006 per cent of m ethylpropene. A fter a second tr e a t
m e n t w ith sulfuric acid th e gas was slowly absorbed b y th e reagent b u t gave no p recipitate.
H u rd and G oldsby (2) rep o rt th a t 2-m ethyl-2-butene gives no precip itate w ith th e acid Denig^s reagent. W ith th e
254 IN D U STR IA L AND E N G IN E E R IN G CH EM ISTR Y VOL. 12, NO. 5 neutralized reagent, th e m ixture of pentenes obtained b y de
h y d ra tin g 2-m ethyl-2-b u tan o l gives a h eavy p rec ip ita te u n d er th e conditions for m ethylpropene d eterm ination, as also does a Cs c u t fractio n ated from d ebutanized cracked gasoline.
T his is probably due to th e presence of 2 -m eth y l-l-b u te n e in these tw o sam ples. T h e possibility of applying th is m ethod to th e pentenes is being studied.
Q u an titativ e te sts of th e effect of 1- and 2-butenes on th e estim ation of m ethylpropene were carried o u t b y preparing sy n th e tic m ixtures an d su b m ittin g th e m to th e d eterm ination.
T h e results are given in T able V.
T h u s 1- and 2-butenes neither give a p rec ip ita te w ith th e reagent nor interfere w ith th e d eterm in atio n of m ethylpro
pene. T h e m ethod is entirely satisfacto ry in presence of C2, Ca, and C4 olefins, b u t pentenes m u st be absent. T o te s t th e effect of air w hich is norm ally p rese n t d u rin g a d eterm in a
tion, a m ixture of m ethylpropene an d air containing 5.90 per cen t of th e form er co n stitu e n t was analyzed an d gave results of 5.96 an d 5.93 per cen t of m ethylpropene.
T a b l e V. A n a l y s i s o f S y n t h e t i c M i x t u r e s o f M e t h y l p r o p e n e WITH 1 - AND 2-BUTENES
S am p le V olum e of D ry G as (S. T . P.)
M e th y lp ro p e n e C o n te n t
N o. H g in P p t. C alcd. F o u n d
M l. Oram % %
1 9 .3 0 .5 8 1 5 1 0 0 .0 100.1
2 1 6 .9 0 .2 2 5 7 2 1 .3 2 1 .3
1 7 .4 0 .2 3 4 5 2 1 .3 2 1 .4
3 2 7 .0 0 .0 7 1 5 4 .1 4 4 .2 3
3 3 .3 0 .0 8 4 7 4 .1 4 4 .0 7
T ab le V I com pares a num ber of determ in atio n s of m e th y l
propene in refinery C* fractions b y th e present m ethod an d by a standardized form of th e sulfuric absorption m ethod. In th e la tte r m eth o d th e gas sam ple (100 m l.) is given tw o passes in to a special bead-packed absorption p ip e t containing 64 per cent sulfuric acid and on each pass is le ft in c o n tac t w ith th e acid for exactly 3 m inutes.
T h e am o u n t of 1- and 2-butenes presen t in th e sam ples of T able V I ranges from a b o u t 28 p er cen t for th e sam ples w ith 20 per cen t of m ethylpropene to ab o u t 12 per cen t for th e sam ples w ith 1 per cent or less of m ethylpropene. T h e sul
furic acid m ethod gives high results, th e percentage error in
creasing w ith increase in th e ratio of 1- and 2-butenes to
m ethylpropene an d , even in th e hands of a w ell-trained operator, is far less precise th a n th e present m ethod.
A single d eterm in a tio n requires ab o u t 2 hours, of w hich 40 to 45 m in u tes are a c tu a l w orking tim e. I n carrying o u t a nu m b er of determ in atio n s th e tim e required averages 40 m inutes for each analysis.
T a b l e V I. M e t h y l p r o p e n e D e t e r m i n a t i o n b y M e r c u r i c N i t r a t e R e a g e n t a n d b y 64 P e r C e n t S u l f u r i c
A c i d
---M eth y lp ro p e n e C o n te n t--- —>
Sam ple S u lfu ric aeid M ercu ric n itr a te
No. m e th o d m e th o d
% %
1 1 .9 0 .6 7
1 .6 0 .6 7
2 3 .1 2 .7 2
2 .8 2 .7 3
4 .4 3 .3
3 8 .8 7 .0 8
7 .2 8 .7 7 .4
4 1 2 .5 1 2 .8
1 2 .5
5 2 1 .1 2 1 .2
2 1 .2 2 1 .2
I f desired, m ercury can be v ery easily recovered from th e filtrates from th e d eterm in atio n s b y adding a n excess of caustic soda solution, w ashing th e yellow p rec ip ita te b y decan tatio n , filtering, drying, an d redissolving th e necessary q u a n tity of th e d ry m ercuric oxide in n itric acid.
A c k n o w le d g m e n t
T h e au th o rs are in d eb ted to M essrs. T rin id ad Leaseholds, L td ., for perm ission to publish th is paper.
L ite r a t u r e C ite d (1) Denigfcs, G., Compt. rend., 126, 1043 (1898).
(2) Hurd, C. D., and Goldsby, A. R,., J . Am. Chem. Soe., 56, 1812 (1934).
(3) McMillan, W. A., I n d . Eno. C h e m ., Anal. Ed., 9, 511 (1937).
(4) Matuezak, M. P., Ibid., 10, 354 (1938).
(5) Spacu, G„ and Dick, J., Z. anal. Chem., 76, 273 (1929).
(6) Treadwell, F. P., and Hall, W. T., ‘‘Analytical Chemistry” , Vol. II, p. 172, New York, John Wiley & Sons, 1930.
(7) Ibid., p . 602.
F ilter Aids
A LLEN L. O LSEN
K a n sa s S ta te College, M a n h a tt a n , K a n s.
K
A F IR f a t a t room tem p eratu res is a p a s ty solid, and in recent investigations considerable difficulty w as encountered in th e usual procedure of purification. E v en ex
cessive am o u n ts of h o t solvents did little to relieve th e diffi
cu lty because th e m a t of adsorbent, th e sm all pores of th e filter paper, and th e sm all holes of th e B üchner funnel pro
longed th e filtration tim e. M oreover, oily co n stitu en ts sepa
ra te d from th e f a tty solids of higher m elting point, so th a t th e p ro d u ct of extraction w as no longer representative.
Several different designs w ere trie d before th e following was chosen as m ost inexpensive and efficient. F o r a B üchner funnel 127 m m . in outside diam eter, an ord in ary 3.785-liter (1-gallon) b u ck e t was c u t to a 10-cm. (4-inch) w all an d a n air in le t an d a dispensing o u tle t wrere soldered to th e b ottom . T he form er served to introduce air from th e pressure line and bring ab o u t a m ore uniform te m p eratu re. T h e rem aining
p a rts of th e device are self-explanatory. T h e w eight of th e u n it rests securely on th e suction flask an d a n a tta c h e d b u re t
clam p serves to stabilize th e ap p a ratu s.
In ac tu a l operation, h o t w ate r is poured in to th e can, air is ad m itte d , an d a sm all flame is directed tow ard th e side of th e can. A fter 20 or 30 m inutes th e te m p eratu re of th e B üchner funnel has reached w orking conditions and th e tre a te d fat-solvent m ixture is poured through.
G re a t q u an titie s of th e m ix
tu re m ay be filtered w ith o u t difficulty.
Co n t r i b u t i o n N o . 2 3 9 , D e p a r t
m e n t of C h em istry , K a n sa s S ta te C ollege, M a n h a tta n , K a n s.
D eterm ination o f Cellulose in Fibrous Agricultural Wastes
A R apid M ethod U sing M on oeth an olam in e
J . DAVID R E ID , G. H . N ELSO N , a n d S. I. ARONOVSKY A g ric u ltu ra l B y -P ro d u c ts L a b o ra to ry , A m es, Iow a
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N A R E C E N T article (19) Wise, P eterson, and H arlow described a prelim inary experim ent in w hich th e y obtained from beechwood a cellulose fraction very sim ilar to Cross and B evan cellulose. T h ey extracted th e saw dust for 5.25 hours w ith h o t (170° C.) m onoethanolam ine, bleached th e residue for 20 m in u tes w ith sa tu ra te d chlorine w ater, and th e n tre a te d i t w ith h o t 3 p er cen t sodium sulfite solution for 0.5 hour.
O ther investigators h av e used dilute alcoholic solutions of m onoethanolam ine in th e isolation of holocellulose from woods, following chlorination (5, 17, 18). T h is lab o rato ry is interested in a rap id m ethod for th e determ ination of cellu
lose. T h e procedure should cause b u t little degradation of th e cellulose an d should be suitable for use on fibrous agri
cultu ral w astes such as straw s, stalks, etc., or th e residue left a fte r th e bacterial ferm entation of such wastes. Previously a critical investigation has been reported b y th is la boratory (16) on a nu m b er of such m aterials (and sprucewood), in w hich th e results obtained b y th e Cross an d B evan (8), N orm an-Jenkins (14), an d K urschner-H offer (5) m ethods of cellulose analysis are com pared. Sufficient q u an tities of th e original sam ples (w ith th e exception of w heat straw ) were still available for com parative analysis.
T h e presen t pap er is, therefore, concerned w ith th e developm ent of a m ethod using m onoethanolam ine as a reagent for cellulose analysis and com parison of th e results w ith those obtained b y th e m ethods of analysis m entioned above (16).
A pproxim ately 300 cellulose de
t e r m i n a t i o n s w e r e m a d e u s i n g m onoethanolam ine on th e various m aterials, a fte r w hich th e result
ing “ crude celluloses” were analyzed for alpha-cellulose, pentosans, lignin, and ash. I t was found from pre
lim inary results th a t m onoethanol
am ine is p articu la rly suitable for th e analysis of fibrous agricultural w astes. T h e cellulose fraction o b tain ed is v ery sim ilar to Cross and B evan cellulose, except th a t th e pentosan co n te n t is usually a little higher. T h e m anip u latio n tim e is from 45 to 60 m inutes per deter
m ination, or less th a n half of th a t required for th e usual Cross and B evan m ethod. T h e cellulose analy
sis of 8 to 10 sam ples of straw s or stalks m a y be com pleted (except for drying an d weighing) in an 8-hour day.
R e a g e n t
W hile technical m onoethanol
am ine m a y be used for th e de
t e r m i n a t i o n o f c e l l u l o s e , t h e
redistilled reag en t was found to be m ore satisfacto ry for this purpose. One sam ple of th e technical grade, w hich gave erratic results, was found to h av e corroded its m etal con
tainer. T h e m onoethanolam ine w as distilled, using a frac
tio n a tin g colum n, an d th a t p ortion distilling betw een 167°
an d 172° C. was retained for use. T h e technical m ono
ethanolam ine costs ab o u t 30 cents p er pound, am ounting to a b o u t 5 cents for each cellulose d eterm ination. A b o u t tw o th ird s of th e used reag en t m a y be recovered b y distillation, th u s reducing this cost m aterially.
S a m p le s
T h e samples, w ith th e exception of w heat straw , were those previously described (16) consisting of ground bagasse, rye straw , cornstalks of 40- to 60-mesh, an d sprucewood of 40- to 60- an d 60- to 80-mesh. T hese sam ples were hom ogeneous b u t n o t necessarily rep resen tativ e of th e whole p la n t m aterial from which th e y were prepared (16). W ashed w h ea t straw w as ground in a chopping mill an d th e portio n passing a 40- m esh sieve b u t retain ed on 60-mesh was used for analysis.
A sam ple of th e sam e washed w heat straw was ferm ented and
T O L E A D S ON H O T P L A T E T H E R M O S T A T
Fi g u r e 1. Ap p a r a t u s f o r Mo n o e t h a n o l a m i n e Ce l l u l o s e De t e r m i n a t i o n
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