When petroleum naphthas are oxidized with air for the purpose of preparing lower fatty acids, in most cases, crystalline matter which mainly consists of succinic acid are discovered when the aqueous layer of reaction products are concentrated. If pure succinic acid can be recovered from this crystal, the economical advantage should become very important. However, since this crystal includes various kinds of impurities, it was impossible to obtain satisfactory results by the known methods which have been applied for the purification of succinic acid.
After a number of experiments, the authors established a suitable process as outlined below for the purpose.
(1) At first, remove the benzene polycarboxylic acids as residue by means of hot water extraction at 100°C. (2) By solvent extraction, remove the materials which easily forms tarry matter when heated in the next dehydrating treatment. For the solvent, benzene, cyclohexane, etc. are desirable. (3) Then succinic acid in the crystal is dehydrated into succinic anhydride at 250°C. Ferrous succinate accelerates the reaction. (4) Separate succinic anhydride from adipic acid, etc. by vacuum distillation with 4 theoretical plates, reflux ratio of 3, and a operation pressure of 30∼50mmHg. (5) Remove the small quantities of impurities included in distillated succinic anhydride by solvent extraction.
According to these processes, succinic anhydride of at least 99.8% purity was obtained with a recovery yield of 80.5%. Succinic anhydride can be easily hydrated to succinic acid.

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Examining the oxidation of o-xylene in the presence of the vanadium oxide-potassium sulfate catalysts suported on silica gel or titanium oxide, it has been found that considerable difference was had in the yield of phthalic anhydride due to the use of these catalysts, which although showed no difference in the yield during naphthalene oxidation.
In order to clarify the effect of these catalysts, change in the composition of the catalysts during the course of the reaction of o-xylene with the catalysts in nitrogen stream has been examined.
From the experimental results we have arrived at the following conclusion.
1. In V₂O₅-K₂SO₄ type catalyst, V₂O₅-SO₃ is responsible for the catalytic action, while K₂SO₄ is carrier of SO₃ and has the role of "fused mixture" formation.
2. This catalytic o-xylene oxidation is constituted mainly of two simultaneous reactions: phthalic anhydride formation and toluic acid formation. The lower yield of phthalic anhydride from o-xylene compared with that from naphthalene has been explained on the basis of the easy oxidation of toluic acid to form carbon dioxide.
3. The difference observed in the yield of phthalic anhydride during the o-xylene oxidation with these catalysts, may be attributed to the difference in their toluic acid formation action.

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A strange behaviour was observed in an experimental work undertaken with the object of determining the accurate viscosities of some solvent refined viscous oils at 20°C using glass tube master viscometers of about 50∼55cm capillary length. The behaviour was that the flow rate increased gradually with repeated measurement and the increment in some case was observed to have maximum value as much as 0.4 per cent or more. The same behaviour was also found when the NBS viscosity standard oil N was filled in the same instruments and repeated for the determination of flow time at 20°C and 25°C.
The authors arranged a research programme with the purpose of explaining this strange behaviour. The solvent refined viscous oil above mentioned was separated to nine fractions by chromatography on Alminagel. Each fraction was then determined the flow rate at 20°C by using the same instruments. Also various analyses including elemental analysis and chromatographic analysis by Alminagel were performed.
It was believed as a result of this investigation, that the reason for this behaviour is probably due to the adsorption of surface-active material in the oils on the surface of glass wall of capillary and to the resulting reduction of bore of capillary tube of the viscometer.

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The disproportionation of toluene to benzene and xylene with the SiO₂-Al₂O₃ catalysts containing various transition metal oxides was studied by a flow method under atmospheric pressure and within the temperature range of 465∼575°C.
The catalyst containing V₂O₃ or Cr₂O₃ showed relatively higher activity, especially V₂O₃-MoO₂ (3:1 molar ratio)-SiO₂-Al₂O₃ catalyst was the most active and was comparatively durable in the carrier gas of H₂ instead of N₂. The kinetical study by this catalyst showed that the kinetic order of this reaction for the concentration of toluene was of the 1st order and the activation energy was 14.4kcal/mol.
Further studies by this catalyst revealed that the addition of phosphoric acid (8%) to this catalyst improved its activity, and the addition of small amount of water vapour in carrier gas resulted in increased reactivity and selectivity to the disproportionation. From the studies on the correlation between the activities and the total acidities of the catalysts, it was found that the acidity improved the activity, but the demethylation of toluene was selectively accelerated in the range of acidity larger than 8×10^-4mol/g.
The results with the AlCl₃ catalyst by the static method at 110°C showed that the rate was proportional to the 2nd order with respect to the concentration of toluene and the 1st order to the amount of catalyst.

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