Yoshimasa Takezaki

Decomposition of Methanol Induced by Methoxy Radicals

Kinetical studies were made at 167°C on the decomposition of methanol induced by methoxy radicals, by pyrolyzing a small amount of dimethyl peroxide in methanol. A considerable amount of ethylene glycol was found. The following mechanism was proposed, and the kinetical equations derived therefrom could express the most part of the reaction quantitatively: CH3OOCH3    →2CH3O,CH3O+CH3OH→CH3OH+CH2OH,  (a)CH3O          →CH2OH,CH3O+CH2OH→CH3OH+HCHO,2CH3O         →CH3OH+HCHO,CH3O+HCHO  →CH3OH+CHO,  (b)CH3O+CHO   →CH3OH+CO  or  2CHO→HCHO+CO,2CH2OH        →CH2OH−CH2OH. The dissociation rate constant of dimethyl peroxide is represented by 4.1×1015 exp (—36.9 kcal/RT) sec—1, and the activation heat of (a) is 3.0∼4.3 kcal higher than that of (b).

Vacuum‐ultraviolet photolysis of ethylene oxide

The photochemical primary processes of ethylene oxide in the vacuum ultraviolet region have been studied with emphasis on the dependence on energy. It has been found that the decomposition into methyl and formyl radicals is the main process while the decomposition into ethylene and oxygen atoms is also important at shorter wavelengths. 1470 A1744 A1783 ∼ 1845 AC2H4O+ h ν→ CH3+CHO(CO+H)111(I)→ O+C2H4(C2H2+H2)0.70.10.1(II)→ H2+(CH2CO)0.10.1···(III)→ CH3CHO0.2······(IV)→ CH2+HCHO0.2······(V) The formation of excited ethylene in Process (II) which decomposes into acetylene and hydrogen has been suggested.

Primary processes of the photolysis of ethylenimine at Xe and Kr resonance lines

The direct and sensitized photolyses of ethylenimine vapor at Kr and Xe resonance lines have been studied. The hydrocarbon products are ethylene, ethane, methane, and small amounts of acetylene, propane, and n ‐butane. Other products detected are hydrogen, ammonia, and the dimers of ethylenimino radicals. The effect of added oxygen or ethylene has also been investigated. Emphasis being laid on the formations of methyl radicals, ethylene, and acetylene, the quantum yields of primary processes are determined as follows; (CH2)2NH + h ν → C2H4 + NH [I], CH3 + (H2CN) [II], and C2H2 + (NH3) [III]; at Xe resonance lines φI = 0.36, φII = 0.41, φIII = 0.028; at Kr resonance lines φI = 0.22, φII = 0.13, φIII = 0.028. Xe and Kr sensitized photolyses have also been studied. A very slight difference in the product distribution between the direct and sensitized photodecompositions has been observed.

Photolysis of Dimethyl Peroxide

Dimethyl peroxide has been photolyzed in vapor phase by 2537 A‐light under various peroxide pressures at temperatures from 21 to 60°C, and for various light intensities at 30°C. The over‐all rate was measured manometrically.The reaction is self‐inhibiting and is also greatly inhibited by a small amount of formaldehyde. The initial rate is expressed by AI+BI½[CH3OOCH3]½ (A≪B and I is absorbed light intensity), and it tends to 3I when formaldehyde is added sufficiently. Carbon monoxide, methanol, and formaldehyde were found in the reaction product. The amount of hydrogen was quite small in the normal run and also in the run where much formaldehyde was added. Based on these results the following mechanism has been proposed: CH3OOCH3+hν→2(H+HCHO),H+CH3OOCH3→CH3OH+CH3O,{CH3O+CH3OOCH3→CH3OH+CH3OOCH2,CH3OOCH2→CH3O+HCHO,CH3OOCH2+CH3O→CH3OH+2HCHO.From the temperature coefficient of the rate, Ea+Eb—Ec= 5.8 kcal, the difference of activation heats, has been obtained; the numerical value is supposed to be the upper l...

Study on the BF3-Catalyzed High Pressure Synthesis of Acetic Acid from Methanol.

さきに行った表題の原応に関する基礎研究に基づき,CH3OH・BF3+H2O・BF3(1:1.5モル比)なる原料を用いて流動法による実験を行い気液接触の方法と反応率との関係を調べた。その結果噴霧法,溢流皿流下法,ガス吹込法いずれも基礎実験結果を再現し, 反応の律速段階は液中反応自身にあり, 気液接触は大して重要な問題ではないことが明らかとなった。なお本合成の実施に関し上記各法の得失についても論及した。次にBF3の少ない場合について基礎実験を行い, 特にCH3OH:BF3:H2O=1:1/4:1の場合について検討した結果,温度を320℃にすれば前同様の収率および速度で反応が進行することがわかった。この場合メタノールの大部分はエーテルとして気相にあり, 反応は液体として存在する水-BF3系内の少量のメタノールにより進行する。またメタノールと生成酢酸が同時に分解するため全反応は複雑であり,連続操作にするには特別の考慮が必要である。