REPORT FOR MANAGEMENT
The Importance of Analytical Chemistry in Industry This month, we bring to a close our series on the relationship of the analytical department to other departments of a modern chemical process industry. Our purpose has been to create a better understanding of the over-all relationship of analysis in the operation and management of a company. Our topflight authors of the several articles in the series have authoritatively accomplished this aim. Our concluding author is John Haslam, chief analyst, Plastics Division, Imperial Chemical Industries, Ltd. Coming as they do from Great Britain, and taken in conjunction with the other articles that have appeared in this series, his observations and remarks draw attention to the live interest which analysts everywhere are taking in their subject. Being an enthusiast, he takes the view that a great deal of the success, or otherwise, of the chemical industry depends in the long run on accurate chemical analysis. As he puts it: " I have met some very good chemists in my time and never one who could prosper on the basis of inaccurate chemical analysis."
JOHN HASLAM Imperial Chemical Industries, Ltd., Plastics Division, Welwyn, Garden City, England
V O L U M E 28, NO. 7, J U L Y
1956
TpOR many years, I have advocated that analytical chemistry is far more than a service function. In fact, its description as such has been a discredit to the field and has in many cases implied that it is an inferior branch of chemistry. Many times I have said that just as much first class chemical knowledge is required to develop a good new method of analysis as to do a piece of chemical research. In fact, many analysts have excellent research minds. Last fall, I gave a lecture at the North West Kent College of Technology, Dartford, which outlined my own experience in the chemical industry and in which I stressed the importance of analytical chemistry in industry. I was naturally glad to see the series begin in ANALYTICAL CHEMISTRY shortly thereafter, in which industrial leaders with great experience were to depict the place of the analytical department in a modern industrial organization. It is a pleasure to have the opportunity of relating my own experiences as the final installment in the series. Many years ago I joined the Analytical Laboratory of the Alkali Division of the large industrial company with which I am connected. It happens that I had considerable experience of analytical work before entering industry, having been engaged, at various times as a pupil of a public analyst, a research worker in a large university (red-brick) engaged in postgraduate research work but with an analytical bias, and a member of the main Government Laboratory, a great training ground for analysts. In those days in that laboratory there were of the order of 100 graduate chemists (besides other assistants) all working alongside one another on quite varied analytical pursuits, including food analysis, water, stronger stuff— i.e., beer and alcoholic liquors—metals, Crown contracts (postage stamps and
postmen's raincoats, etc.), paints and hydrocarbon oils, reagents and equipment covered by the Key Industries Acts, silks, and tobacco. With that background I entered a large scale chemical industry. I think my first impressions were of the size of the industry and, because of that, the prime importance of efficient sampling to the analyst. That particular industry, of course, was concerned with the manufacture of such substances as sodium bicarbonate, carbonate, sesquicarbonate, carbonate monohydrate, silicate, aluminate, and hydroxide; ammonium chloride and carbonate; and calcium chloride through the medium of the Solvay process. In simple terms we can express the fundamental equation of the Solvay process as NH 3 -f- C0 2 + NaCl + H 2 0 i c d u r c - i i i w i K i u ^ liiikuiL'. D r i i i i : . ' . Ι Ί ν - Ι ι ι - a l i i i » . > ' i ' n l i r : i l i m i . .Vuinu. T - n i p - r i i i i : . ' • ii ι· li Ι ϊ· -ι • ι H I · - I i Also available in Stainless. Steel Exturior. It Πιμι-ι.ιΙιιι·' ΚΪΙΙΙ::!-- I ( l i l i e s
|.
I d -|»in -ι 1 "N-ii-ili· i i . Ι" Ι. \ | - | · Ι Ο · Γ · Ι
•_ '..
(
Write Dep't E O - Γ for S u p p l e m e n t N o . 1
2606-1
ACE GLASS I N C O R P O R A T E D V I N E L A N D * N E W JERSEY LOUISVILLE, KY„ 639-41 SOUTH HANCOCK ST
^C^^cnatc
SfredaCi-âte to *?Hdc(4ttif and
^c
ALSO IN STOCK AT OUR I LOUISVILLE WAREHOUSE
For further information, circle number 10 λ on Readers' Service Card, page 51 λ
10 A
the plant, denuded of its bromine, and returned to the sea in such a way that it was not subsequently returned to the plant as sea water of low bromine con tent. He determined the lactometer read ing (as a measure of the specific gravity) and the temperature, and related these figures, from previous calibration data, to salinity (in grams of salts per 1000 grams of water). From previous work he knew that a good factor to use to convert salinity TT^L to bromine content was Bromine content (grams per cu. meter) = ατ^Α Χ 1 • 956 There were other analytical matters which were of importance and which had to be attended to. He had to exercise a rapid volumetric control over the whole process, involving considera tion of the following: 1. Addition of dilute sulfuric acid to bring the pH of the water to 3.5. 2. Addition of sufficient chlorine to liberate the bromine. 3. Aeration of the acidified and chlorinated brine and absorption of the bromine and chlorine in sodium carbo nate solution. That involved the analyst in the analysis of rather complex sys tems containing bromides, bromates, chlorides, chlorates, hypochlorites, hypobromites, carbonates, and bi carbonates. It is true that nowadays sulfur dioxide is used as absorbing agent, but similar considerations apply. 4. Acidification of these absorption liquors. It was an analytical matter how much bromine was being evolved and how much chlorine (undesirable in this case) was being liberated with it. 5. Distillation and purification of liberated bromine. It was an analytical matter to decide on the purity of the finished product. One of the most im portant determinations was that of the chlorine. That determination was car ried out by allowing the sample to re main in contact with pure potassium bromide solution, then boiling out excess bromine and carrying out a potentiometric examination of the residual potassium bromide and chloride. There were other important matters in connection with that plant. Large volumes of air were used in absorption work and, after absorption of bromine from it, that air found its way into the general atmosphere of Hayle. It was an analytical matter to decide whether the bromine content of that atmosphere was excessive. There were medical questions to answer as well, concerned with the intake of bromine. Finally, in another part of this work the analytical work was of fundamental importance. The efficient absorption in sodium carbonate solution of the small ANALYTICAL
CHEMISTRY
REPORT FOR MANAGEMENT
Courtesy Esso Research & Engineering Co.
THE IDEAL PRESS FOR MAKING KBR PELLETS FOR INFRARED SPECTROSCOPE ANALYSIS • 2 0 Ton Press
Capacity
• Accurate eration
alignment
Hydraulic in
op
• Guided moving platen • Sturdy 3 column construction • Even pressure distribution uniformly dense pellets •
amounts of bromine in large amounts of air required well designed absorption vessels. That involved a lot of fundamental work by physical chemists on the study of the absorption of bromine and chlo rine by sodium carbonate under differ ent circumstances. That in its turn meant a lot of important analytical work in connection with the deter mination of the proportions of bromine and chlorine wrhich had interacted with certain sodium carbonate solutions and, further, the amounts of bromine and chlorine present in the atmosphere above such sodium carbonate solutions. It was only with the aid of accurate work of this kind that really sound in formation could be obtained about the equilibria involved.
Organic Analyses
I have dealt with two industries, basically inorganic in character, and at this stage I should like to turn to the organic side. I was concerned, at one time, during the war, in the manufacture of two or ganic substances which may help to give pointers to the importance of anal ysis in industrial work. We were concerned on the one hand with the production of carbamite and on the other with that of monomethylaniline.
for
Carbamite
Self-contained
• Bench mounted
ΟδΗδ
\
• Hand operated
vertical
opening,
A multi-purpose unit with quickly adjusted vertical opening, by handwheel, per mits many different set-ups in minimum time. Used around the world for RESEARCH, C O N T R O L & TESTING. Available accessories include: Heat ing and Cooling Platens; Temp. Con trols; Auxiliary low pressure gauges; Fast air closing; Extruding units; Testing units, etc. Other capacities and sizes available. Write for Bulletin.
LOOMIS ENGINEERING & MANUFACTURING CO. 133 So. 14th St., N e w a r k 7, N . J . Circle No. 12 A on Readers' Service Card, page 51 A
12 A
ΟβΗά
IL / Ν—C—Ν
• 9 " χ 9 " platen area • 22" max. adjustable
Ο
/ C2H5
\ C,H5
was made, if I remember rightly, as a constituent of flashless cordite. Carbamite was produced by the interaction of a monoethylaniline-diethylaniline mixture of high diethylaniline content with phosgene in the presence of sodium carbonate. The point I want to emphasize, however, is that the secondary and tertiary amines had been produced by ethylation of aniline with ethyl chloride. The aniline was produced by the hydrogénation of nitrobenzene. That particular preparation involved the very efficient fractionation of aniline from traces of nitrobenzene (order of 0.02%). We had to determine those amounts. Inconsistent results indicated that our analytical method was not good enough. We were using the established method—i.e., reduction of the nitrobenzene in a stream of carbon dioxide with titanous salt, followed by back-titration of the excess titanous with ferric solution using thio-
cyanate as indicator. We had to employ a large amount of titanous in order to make sure that the nitrobenzene was reduced immediately and not lost in the stream of carbon dioxide. That, of course, involved arriving at the proportion of nitrobenzene by means of the difference between two very large titrations. Really that was a variation of the old flea and elephant idea, and unsatisfactory. Obviously we had to think in other terms, and that is how we came to think in terms of polarographic reduction—i.e., in terms of a simple and direct determination of that nitrobenzene. Briefly, the method we employed was as follows : To 2 ml. of the sample of nitrobenzene is added 0.5 ml. of a solution of 0.1 gram of nigrosine in 100 ml. of concentrated hydrochloric acid. The nigrosine is added as maximum suppressor. The mixture is shaken thoroughly until the aniline hydrochloride fumes eventually produced have dissolved completely. The liquid is then transferred to the cell of the polarograph (Cambridge) and polarographed over the range 0 to —1.4 applied voltage. In deducing a step height, 45° tangents are drawn to the curve at the beginning and end of the nitrobenzene step and the vertical distance between the points of contact of the curve is then measured. The test is standardized in terms of known nitrobenzene-aniline mixtures. As a result of all this, our accuracy was now of the order of two in the third place, instead of two in the second place, thus enabling more satisfactory calculations to be made of the performance of fractionating columns. I would like to mention another matter. During the war, when it became very important to increase aircraft speed, various substances like monomethylaniline were added to the liquid fuel with this object in view. This was made by the methylation of aniline which was produced by the hydrogénation process previously described. Now the effective control of the purity of the product obtained from that plant was an analytical control. It did, in effect, mean boxing of the aniline, monomethylaniline, dimethylaniline compass and, moreover, by relatively simple and direct methods. We had to get away from the diazotization procedure. In the case of the determination of the aniline, we took advantage of the fact that aniline reacts with picryl chloride in ethyl acetate solution to yield a picrylamine and, in turn, liberates hydrochloric acid. On treatment of the reaction mixture with sodium bicarbonate solution, an equivalent of sodium chloride is produced, which is titrated electrometrically with standard silver ANALYTICAL
CHEMISTRY
THE
REPORT FOR MANAGEMENT
BETHLEHEM LAB-LATHE All steel Table w i t h fireproof shelf
VERSATILE
j
LOW IN PRICE l Vertical Set-up (additional charge)
s p e c i f i c a t i o n s : Self-centering sleeve grip chuck; length between chucks 36"; total chuck capacity 0" to 14"; radial clearance 8"; motor %2 H.P., A.C. 115 volts. Complete with motor, chucks and variable speed drive.
Ask for Catalog 54 I Ready to use $ 9 6 0 . 0 0
I
BETHLEHEM Apparatus Company, Inc. HELLERTOWN, PENNSYLVANIA For further information, circle number 14 A-1 on Readers' Service Card, page 51 A
Analysis of Plastics
NALGENE
centrifuge tubes M a d e from the new high density POLYETHYLENE, much publiciz;ed for its high temperature resistance, higher tensile strength, greater rigidity, a n d superior chemical resistance. I t has been tested a t continuous temperatures of 250 °F. compared with 170 °F. for standard polyethylene which means that, now, polyethylene tubes can | H H | TUBES, CENTRIFUGE or TEST Capacity ml Dimensions mm Price ea. be sterilized in a standard autoclave! 75x12 3.5 100 X 13 6.5 100 χ 16 12 115 X 16 13 115 X 19 18 105 X 29 50 162 X 32 100 Conical Type 15 ml capacity Less quantity discounts
.27 .28 .31 .35 .42 .45 .65 .30
At Laboratory Supply Dealers
The
Everywhere
And now, since I wish to draw my examples from first-hand experience, I will turn to the industry with which I am at present connected—the plastics industry. Somehow or other I never feel that the emphasis is the same in this new and rapidly developing industry as in the much older alkali industry. In the latter case one always felt that our real purpose was to try to carry on an old industry with the maximum efficiency. It is true that modern polymers and polymer compositions must be made with maximum efficiency and that in volves a certain measure of shift and day laboratory control. The emphasis I feel, however, is always on change and development. That reflects itself straight away in
NALGE CO., INC.
R O C H E S T E R 2, Ν E W For further information, circle number 14 A-2 on Readers' Service Card, page 51 A
14 A
nitrate solution. Under conditions of the test, monomethylaniline exerts a slight influence which has to be al lowed for. In the determination of small amounts of monomethylaniline, it is necessary to treat the mixture of amines, in ice cold conditions and in the presence of potas sium bromide, with nitrite and acid producing the iV-nitroso compound from the secondary amine, subse quently extracting this with ether, and evaporating the ether solution under carefully regulated conditions prior to weighing. The most novel and yet simplest method involved the determination of the most important impurity in mono methylaniline—i.e., the dimethylaniline. In order to avoid side reactions, the mixture of amines was treated with acetic anhydride at 0° C. The acetylation product was dissolved in water and the solution diluted to volume. An aliquot of this solution was treated with sodium nitrite and hydrochloric acid and the yellow-colored p-nitrosodimethylaniline hydrochloride subse quently measured in a Spekker absorptiometer using dark blue filters. We were able to make use of that principle of acetylation of the primary and secondary base to determine much larger proportions of dimethylaniline by a rather novel, and, this time, volumetric procedure. The acetylation product of the three amines was dissolved in glacial acetic acid and titrated with perchloric acid in glacial acetic acid media using α-naphtholbenzein as in dicator. Under these conditions only the dimethylaniline titrates. Those methods were speedy and, I believe, trustworthy and, moreover, I have good reason to believe were of value in helping to secure, quite rapidly, supplies of monomethylaniline.
YORK
ANALYTICAL
CHEMISTRY
REPORT FOR MANAGEMENT
ast Neutron Survey Meter MODELS E-l and E-1A
rtâuûHat
/
