In our previous report, we stated as follows: inhibitor-filmed catalyst can stop the hydrogenation reaction while inhibitor-film is on the metallic surface. However, as soon as the film is desorbed from the catalyst, it regains its activity.
In this report, we have studied about resisting power against acetic acid of the film, which formed on Ni-catalyst. The filmed Ni-catalyst is used for the hydrogenation reaction of acetoacetic acid ester after dipping it in 5% acetic acid solution. From the reaction products, we have observed that the catalyst would not be affected by the acid, so the film could protect metallic surface. We have also tested that filmed catalyst would be able to use in such a reactant as containing 1% of acetic acid by wt., in which non-filmed catalyst would be poisoned giving no catalytic behavior.
Amine-filmed catalyst was protected from the above mentioned two types of acid as acetic acid could not affect its activity. Acid-amide-filmed catalyst lost its activity gradually according to increasing concentration of acetic acid. Mercaptan-filmed catalyst gave some complex phenomenon. Cetyl mercaptan-filmed catalyst, prepared by dipping Ni-catalyst in mercaptan solution of alcohol or of dioxane, regained the activity above certain temperature at which the inhibitor-film was desorbed, but octyl mercaptan-filmed catalyst, prepared as same as above, could not recover its activity. And moreover, dodecyl mercaptan-filmed catalyst could not regain its activity but when it was prepared in alcoholic solution.

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Impressed current cathodic protection has been applied for protection of internal corrosion of steel pipes carrying sea water at N Co. and M Co. Diameters of pipes are in the range of 10-36 in. Higher current densities and larger anode distances than standard values, which were published by J. H. Morgan in Corrosion, Vol. 15, No. 8, are selected to reduce initial investment. Pipe to water potential at the midpoint of anodes was measured against zinc reference electrode. All sea water steel pipes at N Co. are successfully protected, but the results at M Co. were not satisfactory except 14 in diameter pipe line. The experiment will be continued to improve the performance of unsatisfactory pipes at M Co.

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In the earliest stage-within 72hr at 25°C-of corrosion of Zn, Cu, 7-3 brass and their gold-plated specimens by 5% ammonium polysulphide aq. solution, various corrosion products were observed by using X-ray back reflection and electron transmission diffraction method. On corrosion of zinc, ZnO, αZnS and ZnSO₄⋅3Zn(OH)₂⋅4H₂O were formed contacting with the surface of zinc matrix. In the case of copper, Cu_9-xS₅ alone was detected and corrosion products of 7-3 brass consisted of mixture of CuS, Cu₂S and Cu_9-xS₅ without any compound of zinc.
And moreover, corrosion products formed on the gold-plated specimens of Cu, Zn and 7-3 brass had the same crystallographic forms as the non-gold-plated ones, but the amount of corrosion products of the former is less than the latter. Comparing to corrosion mechanism of such metals and alloys by NaCl aq. solution¹⁾, it is concluded that corrosion in weak electrolyte such as aq. solution of ammonium polysulphide doesn't behave galvanic mainly but as normal solid reaction.

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