Adolph L. Beyerlein

Properties of novel fluorinated compounds and their mixtures as alternative refrigerants

The liquid density, boiling point, critical temperature and critical density are investigated for R-161 (CH 3 CH 2 F, bp = - 37.3°C), CF 3 SCF 3 (bp = - 20.1°C), and RE-218 (CF 3 OCF 2 CF 3 , bp = - 23.7°C); which are potential R-12 and R-22 alternatives. Since the range of applicability of chemicals may be improved by considering their mixtures, the vapor pressure of the mixtures; CH 3 CH 2 F/CF 3 SF 5 , CF 3 CH 2 F/CF 3 SF 5 , and CF 3 (CF 2 ) 2 CH 2 F (R-338mccq)/isopentane; were also investigated. The critical mixing temperature of the CH 3 CH 2 F/CF 3 SF 5 mixtures is above - 30°C which is greater than the normal boiling point of -40°C. Therefore, these mixtures would have limited application as R-12 and R-22 alternatives. The normal boiling point of the R-134a (CF 3 CH 2 F)/CF 3 SF 5 mixtures at the azeotropic R-134a mole fraction, 0.60, is -30.0°C. The critical mixing temperature of the latter mixtures is well below the boiling point and is not a factor in refrigeration applications. The CF 3 (CF 2 ) 2 CH 2 F (R-338mccq)/isopentane mixtures have a normal boiling point of 15.1°C and a critical mixing temperature of about - 5°C which may be acceptable for some applications as a R-1 1 alternative.

Isotope effects on order in nematic solutions. Deuterium quadrupole coupling constants for CDH2I

In a previous publication [J. Chem. Phys. 66, 4226 (1977)] it was noted that dipolar coupling constants obtained from the NMR spectra of mixtures containing 13CH3I and 13CDH2I dissolved in nematic solvents revealed the presence of an isotope effect. In order to investigate this phenomenon quantitatively we have carried out vibrational averaging of the dipolar couplings, and derived the order parameters, Sαβ, for the two molecules. We also derived the quadrupole coupling constant, QD, for deuterium in 13CDH2I from the splitting observed in the deuterium spectrum and values of Sαβ obtained from vibrationally corrected dipolar couplings. The average value of QD was found to be 160.7±1.7 KHz if the asymmetry parameter, η, is assumed zero, and 153.9±1.6 KHz or 168.2±1.8 KHz for values of η=−0.04 and +0.04, respectively.

NMR of oriented CDH2I and symmetry related isotope effects

Measurements of the orientation parameters of a 13C enriched sample of CDH2I in nematic solvent employing 1H, 2H, and 13C NMR are reported. These parameters denoted as SCH, SCD, SHH, and SHD, obey the following relation which assumes mirror plane symmetry: SCD=−2cosα (SHH+2SHD)−2SCH, rather than the following relations which assume C3 rotational symmetry: SCD=SCH=−2cosα SHH=−2cosαSHD, where α equals the HCH or HCD bond angle. Consequently it is concluded that isotope effects on the orientation parameters, such as SCH≠SCD, reported earlier [J. B. Wooten, A. L. Beyerlein, J. Jacobus, G. B. Savitsky, J. Chem. Phys. 65, 2476 (1976)] result from a change in symmetry upon deuteration. The value of α=112.67° that best describes the reported data on CDH2I and CH3I in nematic phase differs from the gas phase microwave value 111.6° suggesting bond angle distortions in the nematic phase. Thus the preferable method of obtaining SCD for quadrupole coupling constant determinations of the CD bond is from the 13CD dipola...

The vibrational and asymmetry corrections to quadrupole coupling constants determined from 13C satellites in 2 NMR spectra of benzene-d1 and acetonitrile-d1

The vibrational corrections have been made to the quadrupole coupling constants of benzene-d1 and acetonitrile-d1 previously determined by data from the 13C satellites in nematic oriented phase. A significant isotope effect on such corrections has been evidenced. The vibrational corrections together with asymmetry corrections result in values for the quadrupole coupling constants which are in good agreement with values obtained by other methods.

Correlation functions for the distribution coefficients of U(IV) and Pu(III) ions between aqueous nitric acid and 30% TBP in an aliphatic diluent

Distribution coefficient correlations for U(IV) and Pu(III) are obtained in terms of a modified form of the total nitrate ion salting strength that was successfully used to obtain distribution coefficient correlations for U(VI) and Pu(IV) in the earlier work of G.L. Richardson. The modification of salting strength was needed to account for the fact that the U(IV) distribution coefficients measured under conditions where U(VI) is present consistently fall below those obtained when it is absent. The correlations were incorporated into the mixer-settler computer model PUBG, and in the simulation of a 20-stage 1B partitioning contactor, calculated product stream concentrations were in excellent agreement with experiment. Earlier mixer-settler computer models, which failed to account for U(IV) distribution coefficients, predicted that U(IV) remained in the aqueous product stream, which is contrary to the experimental measurements.

Deuteron quadrupole coupling constant of deuterochloroform determined from direct 13C2H couplings in 2H NMR spectra

Abstract The deuteron quadrupole coupling constant, Q D , of 13 CDCl 3 was measured in three different nematic solvents employing the quadrupolar and the direct dipolar 13 C 2 H splittings in 2 H NMR. The values of Q D found in Phase IV and EBBA were 158.9 ± 1 and 157.8 ± 1 kHz, respectively, while the value of Q D in ZLI-1167 was found to be 170.5 ± 1 kHz. These results are discussed and compared with literature values obtained in various media in liquid and solid states.

The 2H thermal diffusion isotope effect in benzene and methanol

The 2H thermal diffusion isotope effect is investigated for mixtures benzene−benzeed benzene−o dideuterobenzene, benzene−p didouterobenzen, mathanol d−methanold4, methanol−melhanol d. The thermal diffusion measurements wre made using a cylindrical thermo gravitational diffusion apparatus. (AIP)

Solvent dependence of the deuteron quadrupole coupling constant of CDCl3 determined by 2H spin‐lattice relaxation and Raman line shape studies

The deuterium quadrupole coupling constant in deuterochloroform was determined in an inert solvent (C6H12) and in polar solvents (neat liquid, C6H6, and THF), by combining NMR relaxation data with Raman line shape analysis of the ν1 band (2253 cm−1) of deuterochloroform. The QD value in a 20 mol % solution of CDCl3 in C6H12 was found to be (186±4 kHz), significantly higher than any previously reported value obtained in liquid crystals. A substantial lowering of the quadrupole coupling constant was observed in polar solvents.

Isotope effects on the carbon-hydrogen bond orientation of methyl iodide in nematic phase

Abstract Deuterium substitution which results in no change in molecular symmetry is demonstrated to produce negligible change in the orientation parameter (SCD) of methyl iodide dissolved in nematic phase. Previous indirect estimates of quadrupolar coupling constants (QD), which have assumed SCD = SCH, are high in relation to those obtained by a direct method. This discrepancy is attributed to geometric distortion caused by dissolution of the probe molecule in nematic phase and not to the inequality of orientation parameters.

PUMA — A New Mathematical Model for the Rapid Calculation of Steady- State Concentration Profiles in Mixer-Settler Extraction, Partitioning, and Stripping Contactors Using the Purex Process

The mathematical basis for a computer code PUMA (Plutonium-Uranium-Matrix-Algorithm) is described. The code simulates steady-state concentration profiles of solvent extraction contactors used in the Purex process, directly without first generating the transient behavior. The computational times are reduced, with no loss of accuracy, by about tenfold over those required by codes that generate the steady-state profiles via transient state conditions. Previously developed codes that simulate the steady-state conditions directly are not applicable to partitioning contactors, whereas PUMA is applicable to all contactors in the Purex process. Since most difficulties are encountered with partitioning contactors when simulating steady-state profiles via transient state conditions, it is with these contactors that the greatest saving in computer times is achieved.