By the method reported in the previous paper, thermal cracking of radically polymerized poly-α-cyanoacrylates and its mechanism have been studied. The weight reduction velocities at 200°C were found to decrease in the following order: ethyl>methyl>isopropyl>2-ethyihexyl>n-butyl>isobutyl. This could be expressed by a first order reaction in polymer concentration, and the activation energieswere calculated to be : methyl 22.7, ethyl 22.9, isopropyl 24.2, n-butyl 32.1, isobutyl 31.4, and 2-ethylhexyl 25.5 Kcal/mol. It was found that heat decomposition took place by a radical mechanism. In all cases excluding cyclohexyl polymers, the scission reaction occured on the skeletal chain. Under intense heating, however, side chain degradation also became detectable. Cyclohexyl polymers tend to liberate a large amount of cyclohexene under relatively mild conditions indicating the occurrence of side chain cleavage.
The Fries rearrangement of phenyl caprate was carried out in the presence of anhydrous aluminum chloride in carbon disulfide, and the resulting o-decanoylphenol (b.p. 174°C/6mmHg) and p-decanoylphenol (b.p. 224°C/6mmHg) isolated. The O-isomer was insoluble in, an aqueous sodium hydroxide due to its cyclic chelate structure. Oximes, semicarbazones, and decanoylphenoxyacetic acids were prepared from the decanoylphenols. Decanoylphenols were also converted by the Clemmensen's reduction into decylphenols, which, with subsequent treatment with monochloroacetic acid, gave decylphenoxyacetic acids. Melting points of decanoylphenol oximes, decanoylphenoxyacetic acids, and decylphenoxyacetic acids were determined in order to establish their relationships to the compositions of o-and p-isomer mixtures.
In an attempt to find a new method for the synthesis of trimethyl-hydroquinone (TMH), an intermediate for vitamin E, from pseudocumene (1), the rearrangement of N-(2, 4, 5-trimethylphenyl)hydroxylamine (2) has been studied under various conditions. The hydroxylamine (2), prepared by nitration and partial reduction of (1), was rearranged into TMH in 10% yield on treatment with 10% sulfuric acid at 0-2°C with subsequent heating with 5% sodium hydroxide solution at 90-95°C. Pseudocumoquinol (3), an intermediate for TMH, could be isolated from the reaction mixture in 59% yield when the hydroxylamine (2) was treated with acid. The base-catalyzed rearrangement of (3) gave TMH in 13% yield. In order to clarify the effects of methyl substituents, the rearrangement of other N-(trimethylphenyl)hydroxylamines obtained from mesitylene and hemimellitene was also examined.