RESEARCH absorption of about 6 χ ΙΟ 1 9 electron volts per hour, wliich compares favor ably with doses obtainable from radon a n d accelerated electrons or tons. N o b l e gases, low voltcicje These latter sources of ionizing radia x-rays provide i n e x p e n tion are not readily available. Bardwell sive g a s phase r a d i a t i o n points out. By contrast, gamma rays from a cobaJt-GO s o u r c e are not attrac chemistry research tive for vapor phase work because they Low voltage x- are too pene*tratiii|*. Bardwell and P a l m e r studied the ef ACS rays a n d noble fect of various noble gases on the poly merization of acetylene and 1,3NATIONAL gases mav b e t h e butadiene. The a m o u n t of polymeriza MEETING a B S w e r f o r t i g h t . Physical I budgeted research tion caused l>y energy absorption in t h e Chemistry labs interested in hydrocarbon and the amount of poly vapor phase ra merization caused by energy absorption diation chemistry. in the noble gases are additive. Com And although it's pared with the polymerization rate p e r still too early to predict, industry may mole of the hydrocarbons alone, admix some d a y use this team for vapor phase ing the noble gases increased the rate per mole of gas b y these factors: polymerization of plastics.
Inert Gas Speeds Polymerization
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Dwight C. Bardwell of Yanderbilt University, and coworkers R. C. Pal mer ( n o w with Georgia T e c h ) a n d M. D. Peterson (now with Industrial Reactor Laboratories), have used soft x-rays to polymerize unsaturated or ganic gases. At the same time they've studied the energizing effects of admix ing noble (inert) gases. T h e results were surprising. One molecule of xenon, for example, absorbed as much energy as 150 molecules of acetylene. This absorbed energy, Bardwell told the Division of Phvsicai Chemistrv, is merization of acetylene. T h e noble gas thus acts as an intermediary for absorbing ionizing radiation. Since xenon itself does not react chemically, it passes the energy on to molecules such as hydrocarbons which react as if they h a d been energized directly by a b sorbing t h e radiation. This behavior. Bardwell feels, offers many experimental advantages; he anticipates that valuable fundamental information will be uncovered by vapor phase research using this system. E q u i p m e n t co^t is modest compared to high voltage accelerators or radon from radium. And placing the x-ray tube a n d radiation cell in a container with walls equivalent to * / 4 inch of iron, eliminates the radiation hazard. T h e researchers used a Vanderbilt 50 kv.-50 ma. x-ray unit with a Machlett O E G - 6 0 x-ray tube. A 12S ml. gastight cell was attached directly to the beryllium window of the rube. This unit polymerizes a charge of acetylene (at 700 mm.) at the rate of 1.4r£ per hour. This coiTesponds to an energy
Ace\ yt&ne Neon Argon Krypton Xenon
ο SO GO 14S
1,3-Butadiene 14 28 75
These accelerations, says Bardwell, should definitely b e beneficial because they shorten experimentation time. For example, with 100 mm. of xenon a d d e d to 6 T 6 mm. of acetylene (in t h e 128 ml. cell) at room temperature, 5 6 0 mm. of acetylene polymerized to cu-
prene in two a n d a half hours. Fare acetylene at 67S mm. Hg. on the other hand, polymerized at the rate of 10 mm. per hour.
High P-T Spectrophotometry Possible O R N L d e v e l o p s special cell assembly t o study liquid phase a b o v e normal boiling point
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A special absorption cell, de-
ACS
NATIONAL signed a n d huilt MEETING at Oak Ridge Na Physical tional Laboratory, Chemistry has been used to study aqueous so lutions of neptu nium photomet rically from temperatures near the freezing point t o ahove 250° C. W. C. Waggener of OR XL's chemistry divi sion says he believes this is the first time that spectrophotometry has heen adapted to study liquid phases over a range of 0° to 250° C , and 0 to 1000 p . si.a. Waggener points out that there are techniques for spectral studies of
W. C. Waggener of Oak Ridge National Laboratory checks special cell with which he measures photometric properties of liquid phases over wide temperature a n d pressure ranges. Cell has artificial sapphire windows in titanium mount SEPT.
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from E L E C T R O M E T Metals Research
VANADIUM for the Age of Atomic Power V A N A D I U M M E T A L , due t o
low "neutron capture/* chemi cal stability, and corrosion re sistance, is already In test for nuclear r e a c t o r applications. Vanadium's o t h e r q u a l i t i e s purity, excellent heat conduc tivity, strength a t high tem peratures, good tensile proper ties—have led to its successful application a s a n addition to special alloys prepared by vac uum melting· and consideration for a variety of structural uses in the electronics field. E L E C T R O M E T ' S t e c h n i c a l staff i s available to assist you in ex ploring new applications. The coupon will bring additional data.
Elecfromet FERRO-ALLOYS AND METALS
UNION CARBIDE Thetcrnis"Electromet"and "Union Carbide"are> reg istered trade-marks of Union Carbide Corporation.
Electro Metallurgical Company Division of Union Carbide Corporation Box 268, Niagara Falls, Ν . Υ. Please send m e the Vanadium Technical Data Sheet NAME COMPA2STY POSITION ADDRESS CITY ZONE.
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RE^EA«CH T e m p e r a t u r e h a d various effects o n liquids t o extremely high pressures a t room température a n d t h a t optical t h e profiles of t h e n e p t u n i u m b a n d s . measurements have b e e n m a d e o n Some bands experienced a r e d shift, Some b a n d s fused salt solutions of low vapor p r e s - others a b l u e shift. sures at temperatures u p to a red heat- broadened, while others showed a n u n However, the O R X L optical cell is t h e expected sharpening as t e m p e r a t u r e in W a g g e n e r attributes these first t o provide reliable containment o f creased. radioactive liquids under dual condi- variations to t h e differences in t h e in tions of elevated t e m p e r a t u r e and pres- teraction of the* electron states involved sure, such as those found in a q u e o u s with t h e solvate sphere of t h e solution. media above 100° C . h e told the Divi- H e plans further experiments t o e s t a b lish correlations between t h e effect of sion of Physical Chemistry. Waggener uses a standard G a r y t e m p e r a t u r e a n d solution environment Model 14 M recording spectrophotom- upon these spectra. Also in t h e works eter with t h e special cell assembly. a r e plans for a second, redesigned a s T h e cell, fabricated from annealed t i - sembly. T h e s e plans i n c l u d e : tanium, contains colorless, artificial • I n d e p e n d e n t thermostating of b o t h sapphire windows. Both titanium a n d s a m p l e a n d reference absorption cells sapphire w e r e selected because of their a t elevated temperatures and pressures. excellent corrosion resistance to w a t e r • Methods for rapidly equilibrating a n d aqueous solutions a t h i g h t e m p e r a a liquid sample with a vapor phase. tures. T h e window-mount design is unique, says W a g g e n e r . Spring-loaded, Waggener feels that speetrophotoTeflon ring seals make t h e w i n d o w metric studies of aqueous solutions leak-tight. T h e seals withstand 10ΘΟ a b o v e their boiling points will b e c o m e to 1600 p.s.i. of helium a t r e p e a t e d increasingly important. To support his temperature cycling b e t w e e n 3 0 ° a n d view, h e points to the growing tech 250° C. nology of "aqueous-homogeneous" Four fused-quartz legs with Inconel nuclear reactors, in which t h e fuel h X-trunnions cradle the sample cell arid a heavy w a t e r solution of a soluble reservoir assembly in a vacuum c h a m u r a n i u m c o m p o u n d . ber. These legs a r e fastened to a goldnlated metal base which is kinematically located on three pins. T h e h e i g h t Solid Proof of Solid of each pin is adjustable. T h e sample cell a t a n y o p e r a t i n g State Reactions temperature is optically c o m p a r e d w i t h N e w a p p r o a c h settles o l d a geometrically similar solvent cell thermostated at 25° C. Waggener argument on mechanism o f checked the cell's performance b y e x reactions between p o w d e r e d oeriments with water a n d aqueous s o solids lutions. T h e stability a n d reproduci bility of measurements over t h e entire It seems t h a t design r a n g e c o m p a r e favorably w i t h ACS reactions b e t w e e n those of room t e m p e r a t u r e operation. • N e p t u n y l Ion S t u d i e d . W i t h t h i s NATIONAL p o w d e r e d solids n e w analytical tool, W a g g e n e r m a d e _ _ Inorganic MEETING c a n proceed b y spectral measurements of neptunyl n i solid state dif trate i n 0.1 M d e u t e r a t e d nitric a c i d . Chemistry fusion process a t Deuterated solutions w e r e used to d e low temperatures. crease solvent background interference. Some 3 0 years T h e four ionic valence states of n e p t u ago t h e r e w a s nium (III, IV, V , V I ) all have charac teristic absorption b a n d s i n t h e visible h e a t e d controversy about w h e t h e r s u c h a n d near-infrared spectra, h e explained. "solid state" reactions really do occur Therefore, it was easy to follow the fate or whether mass transport t h r o u g h a of the N p ( V I ) ion speetrophotometri- gaseous or liquid phase is involved. cally a s a function of time a n d t e m Most scientists favored t h e solid state perature. Quantitative, irreversible r e mechanism, a n d the controversy d i e d down. duction of N p ( V I ) t o N p ( V ) o c c u r r e d Within t h e last few years, however, a at elevated temperatures. N p ( V ) r e group of Russian workers has reopened mained stable t h r o u g h o u t the rest of this controversy by reporting experi t h e heating and cooling cycle. mental evidence which indicates t h a t gas phase m a s s transfer is involved m
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