Makoto Takahasi

Study on the photochemical reaction of HCN and its polymer products relating to primary chemical evolution

The photochemical reaction of HCN at 184.9 nm is studied in the gas phase. (CN)2, H2, CH4, NH3, N2H4, C2H6, and CH3NH2 are identified as gas phase products, and a reaction mechanism is proposed. HCN polymers** are also obtained as solid reaction products, and their structure is investigated by Infrared Spectroscopy, UV-Visible Spectroscopy, Mass Spectrometry, and Amino acid Analysis. The process and nature of the formation of the polymers are discussed.

Infrared photochemical reaction of C2F3 C1 induced by a tea CO2 laser

Abstract An infrared photochemical reaction of C 2 F 3 Cl induced by a TEA CO 2 laser was observed. Main reaction products were C 2 F 4 and ClFCCFCl(trans), being quite different from those obtained by thermal or ultraviolet photochemical reactions.

Photolysis of dimethyl ether by 184.9 nm radiation

Abstract The photolysis of dimethyl ether (DME) by 184.9 nm radiation at room temperature was studied. The products CH 4 , C 2 H 6 , CH 3 OH, CH 3 OC 2 H 5 , CH 3 OCH 2 OCH 3 , (CH 3 OCH 2 ) 2 and CH 3 O 2 CH 3 were identified and their quantum yields were determined as a function of the DME pressure in the range 5.3–46.6 Torr. The results of a scavenging experiment with NO and photolysis of the mixture of DME and DME-d 6 led to the conclusion that the photolysis proceeds dominantly through a radical process of CH 3 OCH 3 fission. The quantum yield φ(CH 3 ) of the primary process was estimated to be nearly unity from the calculation of the final product yields.

Photolysis of diethyl ether in the vapour phase by 184.9 nm radiation

Abstract The products in the photolysis of diethyl ether (DEE) were methane, ethane, ethylene, propane, n -butane, ethanol, acetaldehyde, 2-ethoxybutane and 2,3-diethoxybutane (and formaldehyde), and their quantum yields were determined. An appreciable effect of DEE pressure on the quantum yields was not observed within the range 10 – 45 Torr. The effect of addition of nitric oxide, hydrogen iodide and hydrogen sulphide was studied. The dominant primary process is the fission of the C 2 H 5 OC 2 H 5 bond and its primary quantum yield is 0.61±0.05. In addition, methyl radicals (and formaldehyde) are formed through the secondary decomposition of hot ethoxy radicals and/or the direct decomposition of excited DEE. The primary quantum yield of the methyl radicals is 0.20 ± 0.03. Whilst the sum of the quantum yields of the methyl and ethoxy radicals is 0.81 ± 0.07, that of the ethyl radicals is estimated to be 0.87 ± 0.08.

Ion Impact Reaction of Methanol in the Vapor Phase with Accelerated Rare Gas Ions

Methanol at 5 30 mTorr was irradiated with Ne, Ar, Kr, Xe and Nj ions extracted from an RF discharge ion source and accelerated mainly at 5.7 kV. For this ion impact reaction the yields of the identified products (H2, CO, CH„ and HCHO) were determined in terms of irradiation time, ion current and the pressure of methanol. The effects of adding butadiene and water were also investigated. For Kr ion, the dependence of ion energy on the product yields was determined in the energy range 2 6 kV. of ions with molecules are using tandem type mass spectrometers to deal with the dependence of the relative intensities of secondary ions on the energy of projectile ions. The translational energy dependence of the reactions probability of dissociative charge transfer is interpreted on the basis of Masseys adiabatic maximum rule. The main goals of the present study are to identify the reaction channels involved in the impact of rare gas ions with methanol and to determine the excitation functions of the channels, although the detailed elucidation of the reaction mechanism is now only in the preliminary stage of development.

The mercury-photosensitized reaction of tetrahydrothiophene-1, 1-dioxide (sulfolane)

Abstract The mercury-photosensitized reaction of tetrahydrothiophene-1, 1-dioxide (hereafter called sulfolane) was studied in the vapor phase in the temperature range 70 – 130 °C. The major products are SO 2 , C 2 H 4 , C 2 H 2 and c-C 4 H 8 , and the minor products are CH 4 , C 2 H 6 , C 3 H 8 and C 3 H 6 . From a study of pressure effect of sulfolane and several quenching gases on the rate ratios R c 2 h 4 / R c 2 h 4 and R c- c 4 h 8 / R c 2 h 4 , the formation of energy-rich ethylene and normal ethylene in equal amounts is presumed, and the following reaction scheme is proposed: The limiting values of quantum yields at high sulfolane pressure, Φ so 2 , Φ c- c 4 h 8 and Φ c 2 h 4 * were found to be 0.21, 0.04 and 0.17 respectively. From the pressure effect of the quenchers, the values k s / k d and k α / k β for sulfolane, SF 6 , Xe, Ar, He and N 2 were determined. To elucidate further the detailed mechanism, mercury-photosensitized reaction of sulfolane-2,2,5,5- d 4 was carried out. From the analysis of the deuterated ethylenes, it is found that ethylene- d 2 is the major product. It is concluded that ethylene is formed through the fission of the C 3 C 4 bond of sulfolane.