Masao Suga

Isomerization of propyne to allene in shock waves

Abstract Propyne mixtures, highly diluted with Ar, were heated to the temperature range 1170–1440 K behind reflected shock waves. The absorption at 225 nm was followed in order to determine the rate constant of the isomerization of propyne to allene. For the rate constant, the value of k O-A = 7.76×10 11 exp(−55700/ RT ) s −1 was determined.

Experimental methods and techniques for negative-ion production by0 surface ionization. Part III. Compilation and criticism of experimental data on negative surface ionization

Abstract Negative surface-ionization techniques and conditions employed in 470 sample/surface systems in various research fields during the last half century are summarized in a table which presents data for: (1) the sample material (about 200 species in total); (2) the sample gas pressure; (3) the residual gas pressure; (4) the structure of the ion source (13 types classified); (5) the ionizing-surface material (about 40 species); (6) the surface temperature range; (7) the optimum surface temperature; (8) the methods for either separation or identification of ions; (9) the ion(s) produced (about 170 species); (10) the ionization efficiency; (11) the research subject and/or experimental purpose (24 categories sorted); and (12) reference(s) to each datum cited (about 160 references in total). Fundamental information about negative surface ionization may therefore be quickly referenced, in response to a specified research subject and/or a particular experimental purpose. Some problems that should be resolved by further investigations are also summarized briefly. The total number of references cited in this series of reviews is about 430.

Thermal decomposition of vinylacetylene in shock waves: Rate constant of initiation reaction

Abstract The thermal decomposition of vinylacetylene was studied behind incident shock waves over the temperature range 1200–1750 K and over the pressure range 0.3–0.6 atm by tracing the time variation of absorption at 230 nm. The initiation reaction and the rate constant in the thermal decomposition of vinylacetylene were determined from the initial slope of the absorption curve as C 4 H 4 → h 1 , C 4 H 3 +H, k 1 = 6.1 × 10 13 exp (−80 kcal/ RT ) s −1 .

Decyclization of cyclohexene in shock waves

Abstract Cyclohexene mixtures, highly diluted with Ar, were heated to the temperature range 1120–1490 K behind reflected shock waves. The absorption at 253 nm was followed in order to determine the rate constant of the reaction cycle-C6H10 →k 1,3-C4H6 + C2H4. As the rate constant below 1330 K, a value of k = 1.5 × 1015 exp(−66900/RT)s−1 was determined.

Mass spectrometric study of propane oxidation

Abstract By using a quadrupole mass spectrometer-shock tube system developed for fast reactions, the oxidation of propane was studied by observing the time variation of oxygen concentration over the temperature range 1300 – 1800 K and the total pressure range 250 – 450 torr. The relationship between the induction period I and concentrations of both propane and oxygen was determined as follows. I = 5.7 × 10 −13 (Ar) 0 [C 3 H 8 ] 0.7 [O 2 ] −1.3 exp(36000/R T ) Here the units are sec, cal, mol and cc.

Dissociative self-surface ionization of alkali-metal halides

Abstract The emission rates ( n o and n ± ) of neutral alkali halide molecules (MX o ) and of thermal positive or negative ions (M + or X − ) produced on the self surface of polycrystalline alkali halide (roughly 10 3 molecular layers) on a platinum plate (2.0 mm 2 ) were measured simultaneously as a function of surface temperature (about 700–800 K). Quantitative relations between n ± /√ n o and nine factors governing the rates were theoretically derived, and both effective work function and fractional surface area for emitting M + or X − were determined, thereby indicating that M + , X − , and MX o were emitted from different surface sites with quite different values in work function.

Inhibition of the H2O2 reaction by CF3Cl

In this study, the O2 concentration was monitored by the use of a quadrupole mass spectrometer connected to a shock tube, and the additive effect of CF3l on the oxidation of H2 below 1600 K was investigated. The mechanism in the CF3C1-H2-O2 reaction and the rate constant k2 at high temperature were reported. When 0.1 percent CF3C1 was added to the mixture (4 percent H2, 2 percent O2, and 94 percent Ar), the induction period (the elapsed time between reflected shock arrival and onset of the rapid decrease in oxygen concentration) showed little influence of the additive, while the induction period with the mixture containing CF3Cl above 0.5 percent was longer than with the CF3Cl-free mixture. CF3Cl was considered to act as an inhibitor below about 1500 K. 16 references.

Additive effect of CF3Cl on OH∗, CH∗, and C2∗ emissions: Shock tube study with C2H4O2CF3Cl and CH4O2CF3Cl mixtures

Abstract Mixtures of C 2 H 4 O 2 CF 3 Cl and CH 4 O 2 CF 3 Cl, highly diluted with argon, were heated to the temperature range 1350–2200K behind reflected shock waves, and the additive effects of CF 3 Cl on OH ∗ , CH ∗ , and C 2 ∗ emissions in the ethylene and methane combustion processes were examined by observing the delay time, and the intensities of OH ∗ , CH ∗ , and C 2 ∗ emissions. It was found that, in ethylene combustion, the addition of CF 3 Cl prolonged the delay times to the maximum intensities, decreased the intensities of OH ∗ and CH ∗ emissions, and had little influence on that of C 2 ∗ emission. However, in methane combustion, it was found that the addition of CF 3 Cl shortened the delay times to the maximum intensities and to the onset of ignition, increased the intensities of CH ∗ and C 2 ∗ emissions, and had little influence on that of OH ∗ emission.

The reaction of CF3Cl and H2 in shock waves

Abstract CF 3 ClH 2 mixtures highly diluted with Ar were heated to 1400–1600 K behind reflected shock waves. The HCl emission was followed in order to determine the rate constant ( k 1 ) of the reaction, CF 3 Cl + M  CF3 + Cl + M, and k 1 = 2.1 × 10 17 exp(−75000/ RT ) cm 3 mol −1 s −1 was computed.