A number of new red phthalone pigments were synthesized by the reaction of 2-methylpyridinoanthrones with substituted phthalic anhydrides. These were synthesized easily by the same method for the preparation of the analogous quinophthalone pigments. The red phthalone pigments have the same indigoid chromophore as that of quinophthalone pigments which are yellow in colour. It was found that the difference in colour of both pigments was attributed to the difference in the UV spectra of quinoline component. Some pigment properties of these new phthalone pigments were studied. The lightfastness of these were very poor but it could be improved markedly by the substituent at 11-position which could take part in the intramolecular interaction such as intramolecular hydrogen bonding or chelate formation. These new type of red phthalone pigments were suggested as the substitutes for the heavy metal inorganic pigments.
Commercial lacquered bowls, i. e., two black-, two vermilion- and one Suriurushi-Japanese-lacquer finished, and two polyurethane-lacquer finished, were investigated for the effects of the extraction with 4% acetic acid solution and glacial acetic acid. The extraction was carried out at 60°C for half an hour to 7 hours. The Japanese-lacquered bowls, in general, were hardly attacked by 4% acetic acid solution and glacial acetic acid, among which two black bowls resisted more than the vermilion ones. However, the Suriurushi bowl, transparent dark-yellow-colored, was easily attacked by 4% acetic acid solution and glacial acetic acid since the applied Urushi lacquer contained Sienna, an acid-weak yellow pigment. The polyurethane-lacquered bowls (the bodies were made of ABS and Bakelite respectively) well resisted 4% acetic acid solution, but were easily attacked by glacial acetic acid. The spectroscopic and chemical analysis of the coating films of these bowls showed that the black lacquers were colored using some iron compounds as usual, the vermilion lacquers contained cadmopone-type cadmium-mercury red and one of them contained a small amounts of red iron oxide. The yellow lacquer of the Suriurushi bowl was colored with Sienna, and the polyurethane-lacquered bowls were colored with red iron oxide and small amounts of chrome yellow pigment. All the extracts with 4% acetic acid solution showed no contents of Cd and Hg on atomic absorption spectroscopic analysis. The extract from the Suriurushi bowl contained a little amount of iron, whose concentration was still below 1 ppm after 7 hr-extraction. Small amounts of lead without the accompaniment of chromium were extracted from the polyurethane bowls. However, the concentrations of lead in the extracts were still below the maximum permissible concentration of 1 ppm. The amounts of dissolved organic materials in the extracts with 4% acetic acid solution were determined from the potassium permanganate consumption and found to be below the maximum permissible concentration of 10 ppm.