T H E J O I - R L V d L O F I.VDL.STRIAL
600
the absorbed color. The color of t h e dry colored e a r t h is not altered b y mixing with linseed oil, b u t t h e drying property of t h e oil is decreased. X E T H Y L ORANGE--A dilute solution is almost decolorized b y an e a r t h and t h e earths themselvey change co,lor as follows: Kambara earth Iga, Echigo, Ritchu
Pink
Brown to reddish brown
A concentrated solution changes all t h e earths t o orange-red. C R U D E CHLOROPHYLL---Crude chlorophyll solution is prepared by extracting green leaves with ether a n d mixing with bleached rape oil ( R 0 . 0 , Y 0 . 3 2 ) a n d t h e t i n t of t h e solution is R 0.74. I' 2 0 . 4 2 . B 0.16. Five grams of t h e e a r t h were mixed with IOO grams of t h e chlorophyll oil solution, treated a t 110' C., filtered. cooled; t h e result was R o . j o , Y 3 . j , B 0 . 0 0 . A L C O H O L I C S O L ~ T I O KO F C R U D E C H L O R O P H Y L L (1-2.3. B 0.86)-100 grams of t h e chlorophyll solution were mixed with j grams of t h e e a r t h a n d treated a t 2 2 O C . , I O minutes; t h e result was Y I . ; j. B 0.16. AN OIL DYESTUFF-GREEN C O R 1 BASE (Y 1.9, B 3.1) was dissolved in bleached rape oil, treated with j per cent of t h e e a r t h a t a temperature of 2 2 ' C. for I O minutes: t h e result was Y 1 . 7 j . B 0.10. I t appears t h a t t h e bleaching action of t h e e a r t h is not similar in t h e cases of t h e oil dyes a n d t h e dyestuff solutions tested. Although t h e e a r t h has a n effective bleaching power o n a dyestuff solution, i t did not bleach t h e oil so effectively. 13-a C O L O R REACTIOS o s C O D L I V E R OIL .I few grams of t h e e a r t h were mixed with cod liver oil i n a test t u b e a n d t h e n shaken: t h e earth became a beautiful bluish green color. The coloration seems due t o t h e presence of coloring principles i n t h e oil a n d is a \-ery characteristic one. According t o my experiments most other oils have not such a coloration, so t h a t t h i s coloration mould seem applicable t o t h e detection of cod liver oil. SU
M A R Y A i%D C O K C L T S I 0S S
The foregoing investigations seem t o have established t h e following conclusions: I-The K a m b a r a e a r t h has a remarkable bleaching action o n f a t t y oils. a---The bleaching action of t h e e a r t h is affected by the presence of impurities in oils. 3-The bleaching power of t h e earth on oils varies with t h e time a n d temperature of t h e treatments. At low temperatures t h e longer t r e a t m e n t is more effective t h a n t h e shorter. I n t h e case of high temperatures. shorter t r e a t m e n t is better t h a n longer. 4-The presence of air while t h e oil is under t r e a t ment influences t h e color of t h e bleached oil. j-Contact with hydrogen or carbon dioxide while t h e oil is undergoing t r e a t m e n t does not lessen t h e bleaching power of t h e earth. 6---In t h e current of hydrogen or carbon dioxide gas, t h e bleached oil i s very little affected b y tiine a n d temperature. ;-The presence of free water with t h e e a r t h seriously decreases its bleaching power.
. I S D E S G I ~ Y E E R I , V GC H E M I S T R Y
YO^. 7 . S O .
8---The presence of strong inorganic acid with t h e e a r t h lessens t h e bleaching power, b u t phosphoric acid does not affect it. 9-The bleaching power of t h e earth is greatly decreased b y t h e presence of alkalies. Io-Kambara e a r t h heated t o dull redness loses some of its bleaching power. E a r t h heated t o a bright red condition loses its bleaching power entirely. I I-The acid value a n d other chemical characteristics of t h e bleached oil are not different from those of the original oil. 12-0il bleached b y t h e e a r t h method is a desirable raw material for t h e manufacture of hardened oil. 13-The color of t h e spent residual e a r t h depends upon t h e degree of bleaching accomplished. 14-Spent residual earths have no bleaching power. b u t if well washed with solvent, t h e y bleach oil effectively. Well washed spent residual e a r t h has a n acidic reaction t o litmus paper. I j-When K a m b a r a e a r t h is mixed with cod liver oil. t h e e a r t h soon assumes a beautiful bluish green color. This coloration appears t o be applicable for t h e detection of cod liver oil. The author's best t h a n k s are due t o SIr. h l . Tsujimoto, for kind advice i n connection with t h e work reported i n this article. Tns I M P E R I A L L B~~R (Kocuo AT~ SHIKEXJO) RY YETCHIJ-SHIMA, KYVBASHI
TOKYO, JAPAN
THE DETERMINATION OF SULFATES IN WATER BY BENZIDINE HYDROCHLORIDE B y F. W. BRUCKMILLER Received March 25, 1915
Benzidine hydrochloride was first used i n t h e determination of sulfates b y Raschig' who thoroughly developed t h e technic of t h e method for i t s use in coal analysis. Friedham a n d Nydegger' investigated t h e errors i n t h e method with some thoroughness a n d concluded t h a t t h e method was quite as accurate for determining soluble sulfates as t h e quick precipitation b y means of barium chloride. Jacobson," in a search for a rapid method for sulfates i n connection with t h e control of water softening, was t h e first t o use t h e method in water analysis. His conclusions were t h a t t h e method was quite accurate enough for rapid boiler water analysis. His d a t a , however. are meager. t h e results of only six determinations being given wit.h an error of 8 per cent on a n average of 13; p a r t s per million of SO,. With t h e idea in mind of further investigating t h e method a n d obtaining more d a t a on i t s use in water analysis, t h i s work was undertaken. T h e method consists in precipitating t h e sulfate b y means of benzidine hydrochloride. as benzidine sulfate, which, being insoluble i n water, is filtered off suspended in water a n d t i t r a t e d in t h e hot with s t a n d a r d alkali, using phenolphthalein as indicator. This titration is rendered possible b y t h e TTery weak basic properties of benzidine. 1
J
Z . a n g e w C h e i n . , 1903, pp. 617, 818. I b i d . , 1907, p. 9. Illinois \Vater Survey, Bull. 8 (1911), p . 112
601 T h e method of procedure a t first used was t h e same a s t h a t employed b y Jacobson. To 2 j o cc. of t h e water t o be tested. ~ j cc. o of t h e henzidine hydrochloride solution ( z grztms benzidine per liter) were a d d e d . T h e solution was stirred. alloxx-ed t o settle, filtered rapidly b y means of suction. a n d washed with a b o u t 2 5 cc. of water. T h e precipitate was returned t o t h e heaker a n d water a d d e d ; t h e mixture mas heated t o boiling a n d t i t r a t e d with 0 . 0 j S S a O H . using phenolphthalein as t h e indicator. R a p i d filtration w a s best accomplished b y filtering on a disc of filter paper (preferably Schleicher-Schiill S o . j 8 9 ) placed in a Gooch crucible a n d protected b y a W i t t plate. T h e influence of concentration of benzidine hydrochloride was first determined. F o r this work a 0.10 N solution of sodium sulfate was used, being prepared b y exactly neutralizing a given q u a n t i t y of 0.2 1' sulfuric acid with 0 . 2 S sodium hydroxide, Suitable portions of this solution x e r e diluted n-ith distilled water t o give fix-e solutions containing t h e specified a m o u n t s of SO,. Using a variable excess of benzidine hydrochloride. a series of sulfate determinations were, made on each of t h e above solutions. 2 j 0 cc. being t a k e n for each determination. Talile I contains t h e ax-erage of three determinations in each series. Judging from these results. a n excess ot' n o t less t h a n z j per cent of benzidine hydrochloride a p pears satisfactory in obtaining a cornpletc precipitation. I-EXCESS O F BENZIDINE HYDROCHLORIDE REOUIRED T o t a l volume, 500 cc.. benzidine hydrochloride, 2 g . per liter. Excess benzidine P a r t s per million SO4 hydrochloride Per cent Present 0 48 96 192 384 480 Found 10 26 80 180 300 400 1.5 ,3 8 88 186 37.5 460 2.5 48 96 192 384 480 96 I92 35 48 ,384 480 45 48 96 192 ,3 84 480 60 48 96 192 384 480 TABLE
- --_-
-_--
W i t h t h e idea of reducing t h e volume of liquid t o be filtered. a stronger solution of benzidine hydrochloride (8 g . benzidine per liter) 17-as tried with t h e results a s sh0n.n in Table 11.
solution was added in those waters t h a t containc(1 ferric iron. Ferric iron, a s pointed o u t liy Raschig.' reacts with t h e benzidine hydrochloride in such :L manner a s t o give low results. Ferrous iron, however. does not ha\-e this disturbing influence. By using hydroxylamine hydrochloride t h e ferric iron present can be readily reduced t o t h e ferrous condition. T h c hydroxylamine will n o t react with t h e benzidine h y cl r o ch 1ori de. * Using barium chloride, the procedure was as follon-s: 2 5 0 cc. of t h e water t o be tested were evaporatetl t o dryness in a casserole. T h e residue was moistenctl with j cc. of concentrated HCl, diluted with hot ivater a n d filtered. T h e filtrate n-as made u p t o 200 cc. a n d after heating t o boiling I O cc. o f barium chloride i j o g . per liter) were added a t once with \-igorous stirring. After allowing t h e precipitate t o settle over night, t h e B a S 0 4 was filtered off on t o n Gooch crucible. dried a t 180' C . . ignited j minutes on a 3feker burner a n d weighed. . Table 111 contains a few typical results. The rcsults obtained b y both methods agree closely enough for all practical purposes. T h e benzidine hydroT.4BI.E III--CO>fP.4RISOS
Lab. So. 6678 6682 6723 6729 hi42 6804 6887 6941 7081 7082
P a r t s p e r million SO, I.ab. BenziS o . BaClt dine Dit?' 7084 7087 7114 7128 7 1,311 7142 7144 7148 7I 55 iI ih
48 0 16.2
2L.3 51.8
46.0 21.0 2.5 0 6 . 4
--2 0 4 4 x -1 3 +I 6
chloride method. hov-e\-er, has t h e advantage. since xvith i t results can be had in 3 0 ininutes while with t h e barium chloride method 6 hours a n d rnorc. generally 1 2 . are required. Table 11- contains a coniplctc analysis of the [Talers used in Table 111. a n d will gix-c some idca of thc character of the waters on n-hich t h e method was usc~tl. 'rABI.TI I\----COJlPOSITION
Lab. No. City 6678 .itchison TABLE II-SCLF.4Tl3 I S S O D 1 I . M S U L F 4 T E B Y ~ I E I I N PO F B E N Z I D I S ~ HSY D R O - 6682 Arkansas City 6723 Waldo CHLORIDE 6729 Pittsbure Benzidine hydrochloride, 8 g . per 1. 30 per cent excess usrd i n each 2742 Hutchinson determination. T o t a l volume, 300 c c . 6804 Osborne P a r t s per million SOi P a r t s per million SO1 P a r t s per million SO; 6887 XX'ashington Present F o u n d E r r o r P r e s m t F o u n d E r r o r Present F o u n d Error 6942 St. I l a r y s 7081 St. Francis ,300 298 0 --o ;o 10 10.0 0.00 I00 1 0 0 . 1 - 0 . 2 0 7084 Cimaron 30 m.n 0.00 1 5 0 150.1 t 0 . 0 1 3 5 0 3 5 1 . 0 t o ,311 ,io i0.0 n.oo 200 1 9 9 8 -0.10 400 4 0 1 . 0 t o . ? . < 7087 Mineral 7 I I4 \Tinfield i I28 Kanopolis T h e results seem t o be quite a s accurate as those 71.74 Tunction City 7 1 4 2 'F,llis obtaincci with t h e weaker solution, so t h a t in all of 7144 T u r o n 148 Neodesha t h e subsequent n-ork t h e sf-ronger solution of lienzi- 771.55 Ahilene 7 156 Rlue Rapids dine hydrochloride was used.
F o r t h e purpose of investigating t h e adaptaliility a n d accuracy of t h e m e t h o d in determining sulfates in n a t u r a l waters. t h e method was used in parallel with t h e quick precipitation of sulfates b y harium chloride o n about I O O waters of 7-arying composition. T h e procedure with benzidine hydrochloride \vas t h e same as previously outlined with t h e exception t h a t t h e strong 1, en zi di ne hydro ch 1or i d e s ol uti o n ( 8 g. benzidine per liter) was used. a n d t h a t I O CC. of :1 I per cent hydroxylamine hydrochloride
CH1,ORIDE
OF REScI.TS OBT.41NEI) W I T H B.4RII.M A N D WIT11 ~ 3 E X Z I D I N E
P a r t s per million SO4 RenziBaCI? dine Diff. 80.6 84,s +3.9 76.5 80.6 -4.1 2 5 4 . 2 257 1 - . ? , I 87.6 96.0 -8.4 68.i 7 6 8 -8.1 40.3 ---5.1 45.4 5 8 4 . 7 5 8 3 . 7 --LO 62 2 6,3.4 + I 2 29 6 32.6 +3.0 1 7 1 2 180.5 - 7 . 3
Total :;olids 342 800 8 7 ,3 329 0 15 464
129; 5 82
268 844 100.5
24 I 30 1 3.32 .Z 7 3 803
I84 2I5 394
OF \ v A T E R
;\S41,YZlSD
Fe
(p.4KTli P U R ~ I I L I , I ( J X I
tic) C a SIp N a C1 . 10.0 4 0 47.6 19.8 0 3 1 1 6 . 9 2 0 . 2 i 0 i 240.0 4.4 .i 0 6 6 : 5 2 . 0 iii 88.0 9 . 5 io7.n 3 1 . 7 243 406.0 2 . 5 109.0 14 4 31 l Y . O 1 5 . 2 154.7 2 2 . 7 . . 0 . 5 5 8 . 5 26 8 71 1 4 5 6 . 7 4 . 1 28
..
i ' 0 6l..3 8 . 4 5.5 0 I .0 1 2 52.0 I .1 7 8 . 0 1 0 I .2 1 1
...
R?.? 10.8
H C O ? SOr 119 5 268.0
p.6 jfi. i
307.8 2 5 4 . 2 ,330.0 8 7 . 6 264 0 6 8 . 7 39.3 0
4.5
SOX 11 i
2 0 1 . i
+
..
271
..
..
l%X 14.6
.55
.3,3
I ?
F o r ordinary routine water nnalysis t h e follon-in:: procedure is recommended: T o 2 ; o cc. of the w a t e r ( l e s s if t h e SO, content is greater t h a n j o o p a r t s permillion) a d d I O cc. of a I per cent solution of hydroxylamine hydrochloride (more if t h e iron c o n t t n t of t h c water is 1-ery high) and 2 0 cc. of henzidine hydrochloride. Stir \-igorously and allon- t h e silk>- white prc>cipitate t o settle. Filter on a disc of hlaok riblion I
i
LOC.rit. Raschig, LGC.r i i
602
T H E J O C R N . 4 L O F I i V D C S T R I A L A - Y D EAVGISEERI.VG C H E M I S T R Y
filter paper i n a Gooch crucible with suction. Wash twice with cold distilled mater without allowing t h e precipitate t o become d r y . Transfer t h e precipitate t o t h e original beaker. a d d water a n d heat t o boiling. T i t r a t e with 0.0j S N a O H . using phenolphthalein as t h e indicator. 9.6 X cc. 0.0jiV N a O H = p a r t s per million SO,. T h e benzidine hydrochloride solution is made up as follows: Place 8 g. of benzidine i n an agate mortar a n d a d d enough water t o make a paste. Wash t h e paste i n t o a I liter flask, a d d I O cc. concentrated H C l ? a n d make u p t o t h e m a r k . Filter, if necessary. I cc. = 0 . 0 0 2 6 g. Sod. coscLcsIoss I-The benzidine hydrochloride method is applicable for t h e determination of sulfates in water. 11-The results with t h e use of benzidine hydrochloride compare favorably with those obtained with t h e use of barium chloride. 111-The benzidine hydrochloride method is much more rapid t h a n t h e barium chloride method. for which reason it is very well a d a p t e d t o routine water analysis. W A T E R AND S E W A G E LABORATORY U N I V E R S I T Y OF K A N S A S . L A W R E K C E
__~_~___ EXAMINATION OF TOMATO PULP By TV. D. BIGELOW A H D F. F. F I T Z G E R A L D Received June 1, 1915
T o m a t o pulp is prepared i n very large quantities for t h e manufacture of ketchup a n d pulp. While a considerable a m o u n t of pulp used for t h i s purpose is made b y t h e ketchup manufacturers, t h e preparation of pulp for sale as such has reached considerable proportions. There is also a n increasing a m o u n t of t h i s product placed on t h e market in small containers for household use i n t h e preparation of soup. While t h e greater p a r t of t h e pulp placed on t h e market is made from whole tomatoes, t h e r e are a number of plants t h a t manufacture pulp i r o m trimming stock in connection with t h e canning of tomatoes. Since t h e l a t t e r product is given a lower grade commercially t h a n whole t o m a t o pulp a n d has a somewhat different composition, it becomes i m p o r t a n t t o be able t o distinguish t h e t w o b y examination in t h e laboratory. I t is found t h a t t h e results of t h e samples examined in t h i s laboratory during t h e last season afford a basis for t h i s distinction. T h e y also make it possible t o simplify t h e examination which we ha\-e heretofore found necessary. COMPOSITIOS
O F IVHO1.F.
TOJIATO P U L P
T h e results obtained b y t h e examination of 3 3 samples of whole t o m a t o pulp are given in Table I . T h e concentration of t h e samples \-aries from unconcentrated pulp as it r u n s from t h e cyclone, t o pulps of very heavy consistency. This table contains t h e d a t a from m-hich Table I11 a n d IT‘ were calculated, although during t h e season a partial analysis was made of a large n u m ber of other samples, a n d t h e d a t a secured therefrom were in all respects confirmatory of t h e relations calculated from Table I .
Vol.
j ,
50.j
I n addition t o t h e d a t a obtained b y t h e Yarious determinations. Table I gives t h e relation between t h e results of t h e determinations for each individual sample. F o r instance, t h e ratio of pulp solids t o filt r a t e solids (pulp solids divided b y filtrate solids) varies in t h e different samples from 1.091 t o 1 . 1 5 4 , a n d , with t h e exception of t w o samples, it varies from 1.100 t o 1 . 1 4 j . T h e average of t h e 33 samples was 1 . 1 2 . T h e relation of insoluble solids t o t o t a l solids (expressed as per cent of insoluble solids in total solids) is shown in Table I . Considering t h e variations in t h e methods employed b y different manufacturers in t h e preparation of t o m a t o pulp, t h e per cent of insoluble solids in t h e t o t a l solids as shown b y t h i s column is closer t h a n we might expect. Trarying in most of t h e samples from 11 t o 1 4 per cent. T h e per cent of sugar in t h e soluble solids, as shown b y Table I . varies in most of t h e samples from jo t o j j per cent. This figure cannot be expected t o be constant in different localities a n d i n different years. T h e acid, estimated as citric, constitutes in most of t h e samples from 9 t o I O per cent of t h e soluble solids. Of especial interest is t h e refractive constant of t h e filtered liquor? shown in t h e last column of Table I . T h e refractiT-e constant of t h e various samples is much more uniform t h a n might be expected from a product of this nature. On t h e whole, Table I is chiefly interesting as affording t h e d a t a from which Tables I11 a n d IT’ were calculated. T h e uniformity of t h e relations shown in Table IS: is such t h a t i t is usually possible from one determination on t h e filtrate a n d t h e determination of solids i n t h e pulp b y drying t o distinguish pulp made from whole tomatoes from t h a t made from t r i m ming stock. For instance, if t h e specific gravity or index of refraction of a filtrate prepared from a pulp of unknown origin, a n d t h e per cent of solids in t h e pulp b y drying, do not agree with t h e relation between these determinations as shown i n Table I\--i t m a y be assumed t h a t t h e sample was not prepared from whole tomatoes, or t h a t some other substance, such as s a l t , has been added. Moreover, trimming stock pulp rarely conforms t o t h e relations found in whole t o m a t o pulp. For instance, t h e insoluble solids are usually higher a n d t h e acid lower in trimming stock pulp. COJIPOSITIOS
O F T R I h I M I S G STOCK PULP
In Table I 1 are given t h e results of t h e examination of 2 1 typical samples of trimming stock pulp prepared a t different plants a n d i n different localities. This table is of especial interest in showing t h a t t h e relations between t h e results of t h e various analytical determinations differ from those of whole t o m a t o pulps as given i n Table IT. For instance, in S o . 14 j o t h e immersion refractometer reading is .4j.go, a n d t h e per cent of solids is 9 . j 4 , whereas, according t o Table I\’, t h e per cent of solids i n t h e pulp corresponding t o a n index of refraction of 4 j . 9 0 should be 8. j j. T h e specific gravity of t h e pulp is 1 . 0 3 j 3 , which. according t o Table I\-. should correspond t o 8.98 instead of 9 . jq. Of course it cannot be said definitely t h a t a pulp
