Synthesis and Reaction Chemistry of the Disodium Alkoxide of 2,6-Bis(trifluoromethyl)-2,6-dihydroxy-3,3,4,4,5,5-hexafluorooxane

The disodium alkoxide of 2,6-bis(trifluoromethyl)-2,6-dihydroxy-3,3,4,4,5,5-hexafluorooxane, C(7)F(12)O(3)Na(2), 1, was prepared by reaction of the corresponding diol with MeONa in MeOH. This cyclic alkoxide readily mimics the reaction chemistry of the lithium and sodium alkoxides of perfluoropinacol. The reaction of the alkoxide 1 with covalent dichlorides and metallocene dichlorides yields a series of novel bicyclic ring systems. The crystal structure of the trioxasilane, 3, formed from (CH(3))(2)SiCl(2) was determined to provide structural information about these ring systems. Crystal data: C(9)H(6)O(3)F(12)Si, fw = 418.21 u, orthorhombic space group, Pnma (No. 62), a = 15.822(3) ?, b = 12.163(3) ?, c = 7.373(2) ?, V = 1418.9(4) ?(3), and D(calc) = 1.96 g cm(-)(3) for Z = 4 (molecule possesses mirror symmetry). Least-squares refinement on 1075 observed reflections (I > 3sigma(I)) converged with R = 0.0357 and R(w) = 0.0478.     

Accurate electrical and spectroscopic properties ofX 1Σ+ BeO from coupled-cluster methods

Summary This paper reports a series of coupled-cluster (CC) calculations through CCSDT on the theoretically challenging ground state of the BeO molecule. Along with CC methods, quadratic configuration interaction (QCI) approximations to CC theory have been used (QCISD and QCISD(T)), which show several dramatic failings. Equilibrium electrical properties (, _xx , and _zz ) and basic spectroscopic properties (r _e, _e,D _e, and infrared intensity (I)) have been computed. Basis set and electron correlation effects are analyzed in order to arrive at accurate values of the dipole moment and polarizability, which are not known experimentally. For the dipole moment, we obtain a value of 6.25 D, with an uncertainty of about 0.1 D. For _xx and _zz , we suggest respective values of 32 and 36 atomic units (a.u.) and error bars of about 1 and 2 a.u. With extended basis sets, the spectroscopic propertiesr _e, _e, andD _e are reproduced to high accuracy, which is the first time this has been achieved for this species byab initio methods. At the highest calculation levels,I is predicted to be very small. AlthoughI has not been measured, some support for this prediction comes from a recent infrared study of BeO-rare gas complexes. The QCI methods are shown to be much more sensitive to basis set, and even with large basis sets yield values of _zz andI which differ from CC results by an order of magnitude and three orders of magnitude, respectively. These differences doubtless arise from the importance of single excitations (T ₁) for this molecule, as several terms involvingT ₁ are neglected in the QCISD approximation compared with CCSD. We also report CC calculations with Brueckner orbitals, which yield results similar to those obtained with restricted Hartree-Fock orbitals.     

Infrared spectra of Cs3CoCl5

The infrared spectra, transmittance, and polarized reflectance of Cs₃CoCl₅ are reported. The group theoretical analysis was executed and a vibrational assignment proposed on the basis of D_4h symmetry. Factor group and site effects are discussed.     

Rapid separation of microgram amounts of metal ions on stannic antimonate ion-exchange paper

Summary Microgram amounts of metal ions have been separated using stannic antimonate paper. Most of the separations can be accomplished within 15 minutes.

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Zusammenfassung Unter Verwendung von Zinn(IV)antimonat-Papier lassen sich Mikromengen zahlreicher Metallionen trennen. Die meisten Trennungen lassen sich innerhalb 15 min durchführen.

     

Thermoplastic polyurethanes containing 12-hydroxymethylabietanol

Thermoplastic polyurethane elastomers incorporating the resin acid-derived 12-hydroxymethylabietanol (12-HMA) were prepared, and some physical properties are reported. A polyester macroglycol was prepared from 12-HMA, adipic acid, and ethylene glycol. This macroglycol then was combined with either poly(tetramethylene adipate) glycol (PTAd) or poly(ethylene adipate) glycol (PEAd) and 1,4-butanediol to give a glycol blend of 300 average hydroxyl equivalent weight (OHE). The glycol mixture then was combined with diphenylmethane 4,4′-diisocyanate (MDI) (NCO/OH = 1.0) to give urethane polymers soluble in tetrahydrofuran. Polymers were prepared with 0, 5, 10, 15, 20, and 25%, by weight, 12-HMA with PTAd as the other macroglycol and with 0, 10, 15, and 20% 12-HMA with PEAd as the other macroglycol. At 15% 12-HMA, polymers were made from glycol mixtures having 275 and 350 average OHE to demonstrate the effect of changing the hard-segment concentration. The presence of 12-HMA is shown to have its maximum effect on tensile properties at 15–20% in the PTAd series and at 10% in the PEAd series. In general, this effect is an increase in tensile strength and modulus and a decrease in elongation when compared with a similar polymer without the 12-HMA.     

[C7H7] radicals studied by neutralization reionization mass spectrometry; the ortho-tolyl to benzyl radical rearrangement

The collision-induced dissociation characteristics of the benzyl, tropyl and tolyl cations which serve to identify these [C₇H₇]⁺ isomers (the m/z 74–77 relative abundances) were not preserved in their neutralization-reionization (NR) mass spectra. However, analyses of mixtures of the [C₇H₇]⁺ isomers made by comparison of NR mass spectra gave similar results to those obtained from collisional activation (CA) mass spectra. The radicals produced by electron transfer from Xe to tolyl cations were not observed to rearrange to benzyl radicals on the time-scale of the NR experiment, a result in conflict with other gas-phase studies.     

Significance of oligomerization reactions in the transesterification of dimethyl terephthalate with ethylene glycol

Experimental investigations dealing with and mathematical models proposed for the kinetics of the transesterification of dimethyl terephthalate with ethylene glycol were critically reviewed. The models were found to be inadequate, while the investigations were found to be entirely lacking in information about the significance of oligomerization reactions. The significance of these reactions was deduced to be negligible by carrying out an analysis of the kinetics of possible ester interchange and transesterification reactions by use of data on methanol reported in the reviewed literature. This analysis was made possible by the application of numerical quadrature routines in testing the assumed models by the integral method.     

Reference materials for marine science

Summary The second edition of the catalog of reference materials suited for use in marine science, originally compiled in 1986 for NOAA, IOC and UNEP, has been recently completed. The catalog lists more than 900 reference materials from thirteen producers and contains information about their proper use, sources, availability, and analyte concentrations. The reference material matrices include ashes, airborne particulate matter, gases, oils, rocks and sediments, sludges, tissues and waters. Reference materials used for the evaluation of instruments and the determination of sample physical properties are also included. Indices are available for elements, isotopes and organic compounds, as are cross references to CAS registry numbers, and alternate names and chemical structures of selected organic compounds.