Rate constant k 1 of CH 4 ϩ M " CH 3 ϩ H ϩ M was determined from time profiles of IR emission at 3.4 m obtained for a CH 4 /Ar mixture heated by incident shock waves at pressures 0.40-0.82 atm and temperatures 1400-2500 K. The emission decrease due to CH 4 decay in a very short period at the shockfront was investigated. Computer modeling for the decrease gave the k 1 value as: 3.0 ϫ 10 16 exp(Ϫ81.0 kcal/RT) cm 3 mol Ϫ1 s Ϫ1 . The k 1 value was almost the same as those reported by all authors except for the report by Klemm et al. The same technique was used for determining the rate constant k 2 of CH 3 OH ϩ M "CH 3 ϩ OH ϩ M and a new value was proposed as k 2 ϭ 4.2 ϫ 10 16 exp(Ϫ66.8 kcal/RT) cm 3 mol Ϫ1 s Ϫ1.

The thermal cyclization of ethyl α-isocyanopropionate (I) was performed to 5-ethoxy-4-methyloxazole (II) as an intermediate for the synthesis of pyridoxine. The similar reaction of several new alkyl esters of α-isocyanocarboxylic acid to the corresponding 5-alkoxy-4-substituted oxazole was also carried out. The reaction products of the thermal cyclization of I were investigated. When the cyclization was carried out at 180°C for 5 hr, the maximum yield of the main product, II, was 20%; unreacted I (30%), ethyl α-cyanopropionate(20%), and dimer of I (5%) were also obtained. The α-hydrogen of ethyl α-isocyanosuccinate (X) can be more easily removed than that of I, so X may be expected to be more readily converted to 5-ethoxy-4-ethoxycarbonylmethyloxazole (XI), which is also an intermediate of pyridoxine. The yield of XI from X did not exceed 30% because of the side reaction.

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The hydroformylation reactions of acrolein acetals and acetates were carried out in order to discuss the side reactions and any subsequent reactions. Acrolein cyclic acetals reacted with carbon monoxide and hydrogen in the presence of a dicobalt octacarbonyl catalyst to give n- and iso-aldehydes in a 2:1 ratio; they gave no further reaction products. Acrolein diethylacetal underwent hydroformylation using a rhodium catalyst to give n- and iso-aldehydes in a 1:2 ratio. In the presence of a cobalt catalyst, however, various products were obtained. As a result of the acidity of cobalt hydrocarbonyl and a high reaction temperature, n-aldehyde, first formed in benzene, underwent change to 2,5-diethoxytetrahydrofuran and 1,1,4-triethoxybutane. In ethanol, n- and iso-aldehydes gave the corresponding acetals. In the hydroformylation of acrolein acetate, only n-aldehyde was obtained. Iso-aldehyde seemed to be converted into 2-methyl-3-acetoxyacrolein by deacetylation. In ethanol, besides n-acetal, iso-acetal and propionaldehyde acetate, 2,5-diethoxytetrahydrofuran and 2-methyl-3-ethoxyacrolein were recognized. The former seemed to be formed from n-aldehyde by ring closure and ethanolysis. The latter seemed to be formed by the ethanolysis of 2-methyl-3-acetoxyacrolein. In ethyl orthoformate, no side reaction was observed and the yield of the main product, 1,1-diacetoxy-4,4-diethoxybutane, amounted to 80%.