C2 H6 Research Articles

Scrubbing characteristics of CCl4 and C2F6 with a titanium sublimation trap

A quadrupole mass spectrometer with a mass range from 1 to 200 amu gives much useful information about scrubbing of contaminated effluent gases with a titanium sublimation trap. The gases investigated are CCl4 and C2 F6, which have been used to etch semiconductor materials in a glow discharge. The total pressure of test gases was measured with a capacitance manometer. The detailed experimental results of CCl4 for both continuous and intermittent titanium evaporation under various conditions are presented. It is shown that the major constituents in the residual atmosphere are always H2, CH4, and C2 H6. The toxic gas, comprised of mostly chlorine rather than the parent CCl4, was of the order of 0.1% of the total pressure. The efficiency of the trap was demonstrated even though the stainless-steel trap was not cleaned over one month. However, the titanium surface was almost inert for C2 F6.

Diffusive motions in 2D phases of ethane adsorbed on graphite

The diffusive rotational and translational mobility of a simple rod-like molecule, i.e. ethane (C2H6) adsorbed on graphite (0001), has been studied by quasi-elastic neutron scattering, between 5 and 122 K. The motion of the molecules packed in two typical two-dimensional (2D) solids has been investigated One solid (S1) has a herring-bone structure with molecules lying down on the graphite substrate. The second solid (S 3) of higher density is made of molecules standing up on the adsorbing surface. With increasing temperature, a rotational transition is observed, between the rotationally ordered solids and 2D crystals where the C2 H6 molecules exhibit uniaxial rotations about the C-C axis. The characteristic times for these rotations have been measured. At higher temperatures, the S1 and S3 solids melt The molecules in the higher density phase keep their uniaxial rotational motion and in addition exhibit a Brownian diffusion with diffusion coefficient ranging from 2 to 14 x 10-6 cm2. s-1 at 87 and 122 K respectively. For the S1 melted solid, the rotational motion becomes isotropic and the diffusion coefficient ranges from 0.4 x 10-6 Cm2.s-1 at 71.4 K to 50 x 10-6 cm2 . s-1 at 122 K. The activation energy of translational diffusion is about 1.4 kcal. mole-1. These results are compared with the mobility of C2H6 in its bulk phases.

Solubility of non-polar gases in 1,4-dioxane, at 285.15 to 303.15 K

Solubility measurements of several non-polar gases (He, Ne, Ar, Kr, Xe, H2 , D2 , N2 , CH4 , C2 H4 , C2 H6 , CF4 , SF6 and CO2 ) in 1,4-dioxane, at 285.15 to 303.15 K and a partial pressure of gas of 101 kPa, are reported.Experimental results are compared with those obtained from Hildebrand’s semiempirical approach. The special behaviour of CO2 is made plain.Gibbs free energy, enthalpy and entropy of solution, at 298.15 K and 101 kPa partial pressure of gas, are evaluated.Besides, using the scaled-particle theory, Lennard-Jones (6, 12) pair potential parameters for 1,4-dloxane were also determined.

Dissociation of ethane by electron impact

The absolute total dissociation cross section for ethane is reported for electron energies between 10 and 600 eV. A maximum value of 7.6 × 10−16 cm2 occurs at 80 eV while the apparent threshold is ≈ 10 eV. Dissociative ionization is more probable than dissociation into neutral fragments at all energies except in the threshold region. The data indicates that fragmentation involving methane elimination (c− + C2 H6 → e− + CH4 + CH2) occurs in less than 2% of the dissociative events for 50 < E < 600 eV. Arguments are presented which suggest that some of the lower excited states of ethane are stable against dissociation.

Crystal and molecular structure of monoglycine nitrate

The crystal and molecular structure of monoglycine nitrate (C2 H6 NO+ 2, NO− 3) has been determined by single-crystal X-ray diffraction methods. The crystals are orthorhombic: space groupP212121,a = 16.42(6),b = 6.10(4),c = 5.61(5) A andZ = 4. The structure has been solved by direct phase determination methods, using visually-estimated intensity data, and was refined to anR -value of 0.064, using counter-measured intensity data for 660 reflections. The anomalous scattering by oxygen and nitrogen atoms suggests the present configuration. The molecule in the structure exists as+NH3CH2CO2H, NO− 3. The glycinium molecule is planar, except for the N(amino) atom, which deviates by 0.48 A from the molecular plane defined by the atoms C(1), C(2), O(1) and O(2). The torsion angle N(1), C(2), C(1), O(1) is 20.7 °. The NH3 group is a donor of three hydrogen bonds of equal strength (N ... 0 = 2.85 A). Two of the hydrogen atoms of the NH3 group also form weak bifurcated hydrogen bonds (N ... 0 = 3.04 A). One of the carboxyloxygen atoms is a donor of a hydrogen bond (0 ... 0 = 2.65 A). The oxygen atom of the carboxyl group and the oxygen atoms of the nitrate group are all acceptors of hydrogen bonds.

New ferroelectric compound SrTeO3

A synthetic compound SrTeO3 was discovered to exhibit ferroelectricity in the temperature range between 312 and 485°C. Small single crystals could be grown by the Kyropoulos method. The crystal belongs to the monoclinic system and its space group is C2/ c − C2 h6 at room temperature. A pronounced dielectric anomaly was observed along the b axis at 485°C. The value of the spontaneous polarization, obtained by the D-E hysteresis loops at 50 Hz, is 3.7 μC/cm2 at 312°C.

Low Frequency Vibrations of Molecular Crystals. XIII. CH3AsCl2, CH3AsBr2, CH3Asl2, and CD3Asl2

The ir spectra from 4000 to 33 cm−1 have been recorded of CH3AsCl2, CH3AsBr2, CH3Asl2, and CD3Asl2. The Raman spectra of each of these compounds have been recorded and depolarization values measured for CH3AsCl2 and CH3AsBr2. The observed spectra have been successfully interpreted on the basis of a pyramidal skeletal structure of Cs symmetry. The observed values for the Teller–Redlich product rule for the assignments of the normal modes of the CH3Asl2 and CD3Asl2 molecules are in reasonable agreement with the theoretical values for both symmetry species. The As–CH3 torsional mode was tentatively assigned in the ir spectrum of solid CH3AsBr2 at 134 cm−1 and the torsional barrier calculated to be 461×30 cm−1 (1.32×0.08 kcal/mole). The low frequency bending modes of solid CH3AsI2 and CD3AsI2 have been found to show correlation field splitting and have been successfully explained in terms of the four molecules per unit cell with a space group of C2 h6.