carbon in the water phase for the first equilibration and the last equilibration can be calculated, plotted on semilog paper, and extrapolated back to zero equilibration. Dr. McAuliffe has found that the first equilibration removes the majority of alkane hydrocarbons, and three equilibrations remove the majority of cycloalkanes. This leaves predominantly aromatic hydrocarbons in the aqueous phase. Olefin and acetylene hydrocarbons distribute between the water and gas phases with different distribution coefficients from alkane, cycloalkane, and aromatic hydrocarbons. If present in the water sample, they can also be identified and measured. For example, the percentages in the gas phase, calculated from solubilities and vapor pressures (for equal volumes of gas and distilled water), for 1-pentene, 1,4-pentadiene, and 1-pentyne are 94, 83, and 5 1 % , respectively. One of the principal advantages of the method is its ability to determine hydrocarbon concentrations accurately in solutions of varying ionic composition, Dr. McAuliffe points out. It doesn't matter whether the water is fresh or brackish, or is sea water, or subsurface brine. Within 1%, the same final value is obtained from waters of widely varying salinity, even though the distribution coefficients are changed markedly. Separation. The method gives good separation of hydrocarbons from highly water-soluble organic compounds, such as alcohols, aldehydes, ether, and acids, the Chevron scientist says. Because of the high water solubilities of these organic compounds, the distributions are highly favored toward the water phase, and little or none of these compounds is found in the gas phase. Dr. McAuliffe says that the method can detect alkane and cycloalkane hydrocarbons in water if they are present in amounts of one to three parts in 10 12 of water by weight (parts per trillion, p.p.t. ). Because of their lower partitioning into the gas phase, aromatic hydrocarbons can be detected in concentrations of 4 to 12 p.p.t. Methane partitions between the atmosphere and surface waters with about 3.5% in fresh waters, and is present in open ocean waters in amounts of 28 to 36 p.p.t. With the Chevron scientist's procedure, methane can be detected at 1 p.p.t. or less. Sensitivity of the method can be increased by analyzing a larger sample of the gas phase and by increasing the ratio of water to gas, Dr. McAuliffe says. The method should be valuable in water pollution studies in which a complex mixture of hydrocarbons is dissolved in fresh or salt water.
Hydrogen polyoxides found at low temperatures Infrared and Raman spectroscopy used to identify H203 and possibly H204 The existence of hydrogen polyoxides—including hydrogen trioxide, H203, and possibly H 2 0 4 —has been reported by Dr. Paul A. Giguère, Laval University, Quebec. Dr. Giguère related his findings—based on evidence from infrared absorption and Raman spectroscopy—to the Physical Chemistry Divisions ( A C S / C I C ) . Controversy and doubt have long swirled around the existence of these exotic higher hydrogen oxide species, and a few investigators have claimed to observe them, particularly a group of Moscow chemists led by L. I. Nekrasov. Now, a lengthy and difficult series of experiments, carried out over several years by Dr. Giguère and coworker K. Herman, has thrown new light on the higher oxides of hydrogen. The Laval chemists measure infrared absorption, between 300 and 4000 c m . - 1 , of the products from electri-
cally dissociated H 2 0 or D 2 0 vapor, or related systems, trapped at liquid nitrogen temperature. They use the isotope effect of deuterium to overcome blocking of O-O vibration bands by strong libration bands of H 2 0 and H 2 0 2 in the 600 to 900 cm.-^region. Frequencies shifted. Three new absorption bands are thus obtained in the deuterated systems, at 440, 760, and 820 c m . - 1 . By a second isotopic substitution, of 1 8 0 to get D 2 0 1 8 , these frequencies are shifted to about 420, 717, and 775 c m . - 1 , precisely as Dr. Giguère expects for 0 3 skeletonstretching (760 and 820) and chainbending (440) modes. He therefore identifies the IR spectra as those of H 2 0 3 molecules—or rather D 2 O a here—trapped in the frozen products of dissociated water vapor. Mixtures of the two oxygen isotopes indicate, moreover, that the molecule responsible for the IR absorption must contain more than two oxygen atoms. Additional identification of the new IR bands is provided by following their disappearance with time on raising the temperature of the sample. For example, at - 6 5 ° C. the 760 c m . - 1 band drops in five hours to half its original intensity, showing breakdown of H 2 0 3 .
Deuterium reveals three new IR bands, attributed to D2O3 g 0.00
JUNE 8, 1970 C&EN 73
Is Glass the Answer
tration—perhaps 5 mole per cent in dis-^ sociated water, and somewhat more in systems richer in oxygen. The existence of these hydrogen polyoxides has significance for chemical valence bond theory, thermodynamics, and reaction kinetics. It has been postulated by some scientists that the polyoxides occur as intermediates in hydrogen-oxygen reactions, combustion, flames, and in pulse radiolysis of aqueous solutions of acids. As members of a homologous series beginning with H 2 0 and H 2 0 2 , they illustrate the reluctant catenation (chain formation) of oxygen, unlike its congener in the periodic table, sulfur, which forms compounds u p to H 2 S 8 . T h e prospects for stabilizing and isolating H 2 0 3 or H 2 0 4 in a bottle are therefore rather poor, says Dr. Giguère.
Raman spectra. The two Quebec scientists, together with Dr. X. Deglise, have also investigated the Raman spectra of the materials, observing a fourth band at 500 c m . - 1 , besides the three bands in the IR spectra. Furthermore, they cannot account for the intensity pattern of the first three bands in terms of H 2 0 3 molecules only. Dr. Giguère therefore concludes that a species besides H 2 0 3 is present, and hypothesizes it to be H 2 0 4 . Chemical bond energy considerations indicate that H 2 0 4 molecules should be too unstable to exist, except at temperatures even lower than liquid nitrogen, but he suggests that extra stabilization in both species—H 2 0 3 and H 2 0 4 —might be provided by hydrogen bonding. At any rate, the higher oxides would exist only in low concen-
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ing carbonyls in [ N i ( ^ C 5 H 5 ) C O ] 2 ,
The oxygen end of a bridging carbonyl group may exhibit basicity toward aluminum alkyls. And this Lewis basicity appears to be a general phenomenon, according to D . F . Shriver and coworkers at Northwestern University, Evanston, 111. Although many compounds are known in which cyanide is coordinated through both carbon and nitrogen, until recently the isoelectric CO ligand had been known to bond only through carbon. Last year, the Northwestern group described the first observation of carbon and oxygen coordinated CO in the compounds [ F e ( ^ C 5 H 5 ) ( C O ) 2 ] 2 • 2A1(C 2 H 5 ) 3 and [ F e ( ^ C 5 H 5 ) C O ] 4 · 4A1(C 2 H 5 ) 3 . Dr. Shriver told the inorganic Chemistry divisions (ACS/CIC) that bridg-
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