THE CHEMICAL WORLD THIS WEEK
Left. C. F . Tufts, Sylvania, points up surface geometry and structure effects on a hlackboard sketch. Right. Keynote speaker, S. E . Q. Ashley of General Electric ( l e f t ) , is being introduced by the symposium chairman, R. P. C h a p m a n of American C y a n a m i d C&EN REPORTS: ACS Division of Analytical Chemistry
Instruments Face A d v a n c e m e n t of A n a l y t i c a l Chemistry Role of three orders chemistry e v a l u a t e d EAST L A N S I N G , M I C H . - I n the sleek surroundings of Michigan State College's ultra-modern Kellogg Center, the fifth annual summer symposium on analytical chemistry found here last week the proper background to support its premise that analytical is a most modern and progressive branch of chemical endeavor. About 250 chemists attended the symposium, sponsored
by
the
AMERICAN
CHEMICAL
SOCIETY'S Division of Analytical Chemistry, and by t h e Society's publication Analytical Chemistry. Keynote speaker for t h e two-day conference was S. E . Q. Ashley of General Electric, w h o proposed a new approach in evaluating t h e role of analytical chemistry as a science. Rather than consider it to consist of only two orders—professional a n d subprofessional, or research and "routine"—Dr. Ashley cited three orders in which analytical is exercised on a professional level. Of t h e three, research, teaching, and practice, Dr. Ashley singled out the "practice" of analytical chemistry as the least well recognized, although it provides t h e major professional outlet for chemists in the field today. Likening t h e professional practice of analytical to t h e professional practice of medicine, D r . Ashley observed that this phase of chem2698
of
professional
analytical
istry demands a high order of professional skill, calling for the broadest a n d best informed sort of chemical education. T h e symposium itself, devoted to problems in the analysis of materials for ingredients of unknown constitution, was divided into two sections which covered first the tools, techniques, and m e t h o d s used by t h e analytical chemist, a n d second t h e application of those devices to specific problems in chemical analysis. S p e c t r o s c o p y . In t h e examination of many mixtures of unknown or ill-defined composition, particularly such complex ones as petroleum and coal tar fractions, animal and vegetable oils, or packingT H I S IS I N D E X ISSUES Because of the l a r g e size of C & E N many readers now f i n d i t convenient t o b i n d the annual v o l u m e in f o u r parts. For those readers a se+ o f suitable t i t l e pages, which always a p pear in the " i n d e x " issue, w i l l be furnished f r e e . Address requests t o C h e m i c a l and Engineering News, 1155 Sixteenth St., N . W . , W a s h i n g t o n 6, D. C . C H E M I C A L
house by-products, m u c h useful information can be gleaned by means of infrared, Raman, and ultraviolet spectroscopy, said O. D . Shreve of D u Pont. O n e t y p e of spectrum may give information where t h e others will not, while in some instances t h e data may overlap to provide supplementary or confirmatory evidence. A fairly recent development in t h i s area, said Dr. Shreve, is t h e use of spectroscopic d a t a to establish, empirically, a suitable set of characteristics for complex m a t e rials, without regard to their actual chemical composition. T h u s it may be possible to identify a given manufacturer's phenolformaldehyde resin, for example, by its characteristic absorption pattern, even though the exact chemical m a k e - u p of t h e resin is not determined. T r a c e r Techniques. T h e increased availability of radioactive isotopes has furnished t h e analytical chemist with a timesaving tool for solving many difficult p r o b l e m s , according to James E. H u d g e n s of the A E C . Tracer techniques have b e e n used successfully in determining trace element concentrations, and in revealing t h e c o m position of materials; the sensitivity of the methods makes t h e m particularly useful in the determination of impurity concentrations in samples of p u r e materials. Several tricks have been developed to increase the utility of the tracers. For example, said Dr. Hudgens, a m i n u t e sample of unknown to be analyzed may b>e r a d i o activated and then mixed with a l a r g e amount of the element in question in its inactive form; this provides quantities of material sufficient to allow t h e use of ordinary analytical procedures. After applying corrections for losses, it is t h e n possible to calculate back to establish desired values for t h e original small sample of unknown. Surface Phenomena. There i s danger of serious error in attempting to interpret a material's complete behavior i n a variety of environments, if the sample's surface geometry and structure are n o t t a k e n fully into account, w a r n e d C. F. Tufts of Sylvania Electric Products. In current analytical procedures, h e said, interpretations of bulk sample behavior a r e often m a d e on the basis of examinations cond u c t e d at critically prepared surfaces. D a t a from light microscopy, electron microscopy, and electron diffraction, h o w ever, can be integrated to give precise surface descriptions, allowing appraisal of t h e fidelity of the surface, and correlation of surface properties with the properties of t h e bulk sample. Analysis by Pyrolysis. Certain classes of materials not normally a m e n d a b l e to analysis by mass spectrometry may b e pyrolyzed to give characteristic, volatile decomposition products readily analyzed in conventional mass spectrometers; the records thus secured m a y b e interpreted AND
ENGINEERING
NEWS
so as to identity the original material. In most cases, said Paul D. Zemany of General Electric, very rapid heating of the sample gives the simplest decomposition products, which usually have obvious relationships with the original material. In the case of linear homopolymers, the monomer comprises the bulk of the volatile material obtained by rapid, high temperature (above 800° C.) pyrolysis. Slow, low temperature pyrolysis may give a very complicated mixture of products. In the case of more complex materials such as biological samples, said Dr. Zemany, the pyrolysis products may not all be identified, but standardizing the conditions of pyrolysis results in characteristic mixtures which may be compared with known materials. Nonmetallic Compounds in Steels. The two basic problems in determining the nature and extent of nonmetallic constituents in metals are the isolation of the compounds by a valid method, and identification and analysis of the isolated constituents, said H. F. Beeghly of Jones and Laughlin Steel Corp. One of the oldest methods of isolation, that of the reaction of halogens with the metals under various controlled conditions, is in perhaps the most active state of development of all the methods in current use. It is of particular importance in isolating compounds of nitrogen, present in all steels, and lately much in the limelight in metallurgical research. Solutions of bromine or iodine in anhydrous aliphatic esters have been found most useful in this work, Dr. Beeghly reported; bromine in methyl acetate is most commonly used. So far as can be determined, the esterhalogen methods are the simplest devised to date, and are the only ones available for separating from steel the nitrides that are not stable in the presence of aqueous acids or alkali; aluminum nitride is an example of such a compound. The esterhalogen method has also brought to light the fact that the thermal history of a specimen must be taken into account in selecting a sample for the isolation of nitrogen compounds. Thus, said Dr. Beeghly, the extent of recovery of aluminum nitride nitrogen from commercial heats of steel deoxidized with aluminum may vary widely, depending upon the stage in production at which the specimen is removed from the heat. There is no fixed rule that can be applied to the isolation and identification of nonmetallic compounds from metals, Dr. Beeghly stated; the methods must be tailored to suit the particular metal and the compounds to be isolated. When two or more deoxidizing agents (e.g., aluminum, silicon, and zirconium) have been used in the same steel, the problem of identifying the nitrides and determining the amounts of each present becomes more complicated. However, said Dr. Beeghly, recent work with different wash solutions following the ester-halogen isolation step indicates the possibility of distinguishing the soluble nitrogen combined with aluminum from that associated with silicon or zirconium. V O L U M E
3 0,
NO.
26
•
»
C&EN REPORTS: National Fertilizer Association
Small Fertilizer Plants M a y Be Replaced w i t h Large Installations Nitric acid acidulation of phosphate rock on large scale foreseen WHITE SULPHUR SPRINGS, W. VA.Monumental changes must take place in the fertilizer industry in the next few years if the nation's ever-increasing needs for plant food are to b e met. This prediction was made by James E. Totman before 800 members and guests at the National Fertilizer Association's 27th annual convention held here June 16 to 18. The convention was the largest in the association's history. One of the principal developments envisioned by Mr. Totman, chairman of the board of NFA, will be the production of available phosphoric acid in forms other than superphosphate. The shortage of sulfur and consequently of the sulfuric acid necessary to acidulate phosphate rock to produce superphosphate may be overcome b y developing other sulfur sources than brimstone. This development, however, will greatly increase sulfur costs. Several possible methods of producing phosphoric acid are being studied. Pilot
plant research is being carried on by TVA. One promising TVA method, Mr. Totman noted, uses a mixture of nitric and sulfuric acids for acidulation, followed by ammoniation of the acidulated products and finally addition of potash, producing a complete fertilizer. The ammoniation step alone requires as much anhydrous ammonia as that used in the manufacture of the nitric acid used for acidulation. If this method were to be used, it would probably require large, multimillion-dollar, completely integrated plants including nitrogen fixation facilities, nitric and sulfuric acid plants, and acidulating and mixing plants. A few large integrated plants might pose a severe problem for many of the 205 separate acidulation plants which produce superphosphates for sale to 800 dry mixing plants. Mr. Totman believes that if this stage is reached, large plants will be used to supply a few of the 900 separate and distinct grades of fertilizer
O/^d0l>
excellent medium-boiling solvent
for
nitrocellulose
resins. It is f a v o r a b l y
METHYL
lacquers
and
vinyl
priced—compare
it
with other solvents. MIK is one of the many solvents that
is r e a d i l y
available
in com-
mercial quantities from C a r b i d e . SPECIFICATIONS
w&gfflmm
Boiling Range, °C. at 760 mm. Hg. ... Flash Point, CF. (Cleveland open cup). Pounds per Gallon Maximum Color, Pt-Co scale
14-117 ....75 ..6.77 ....15
For prices a n d a d d i t i o n a l inf o r m a t i o n , call
the
Carbide
office nearest y o u .
CARBIDE Am CARBON
xmmickis COUPANT A Division of
Union Carbide and Carbon Corporation
um 30 É. 4.2ficTSt.,.Nêw York 17, N.Y. Offices in^Principal. Cities^ .InCanadd: Carbide arid Carbon Chemicals, Limited1, Toronto »
JUNE
3 0,
1952
2699
