1961 年 19 巻 2 号 p. 124-130
The methods of starting of reaction, conditions for starting of reaction (amount of flow of methanol and the mixing ratio of air and methanol) in manufacturing of formaldehyde from methanol and in connection with the forms of catalyst, the effect of the methods of starting of reaction on the following reaction stages have been investigated. In the methods of starting of reaction, the methods of using of platinum oxide-asbestos was studied at first. The reaction was started by preliminary heating at 80-90°C under a suitable condition but it was shown that there were some increased formation rate of carbon monoxide and carbon dioxide. Then the standard method of starting of reaction in a tube with small diameter by heating the wall filled with catalyst was investigated and it was found that the necessary temperature for preliminary heating was about 240°C in case of using of activated silver catalyst. The method of starting of reaction in a tube with large diameter by using the internal heating equipment in the reaction vessel was investigated and it was indicated that using of an electric heater with about 1/7 of heating area of total section area of reaction tube gave a satisfactory result. The rate of flow of methanol and the ratio of air/CH30H at the time of starting of reaction were investigated and these values were found to be 0.3-1.0g/cm2/min and 0.3-0.4l/g, respectively In case of using of piled layer of circular net catalyst having a diameter equal to that of reaction tube, by the simple heating of the wall, good yield was not obtainable but replacing it for platinum oxideasbestos method gave the result comparable to that of using rolled-type catalyst. Thns, the selection of the method of reaction must be done carefully in consideration of the form of catalyst.