Abstract: The process for the catalytic oxidation of hydrocarbons and more particularly of petrolatum of similar raw material having a high content in microcrystalline waxes comprises introducing a molecular oxygen-containing gas into melted petrolatum in the presence of a usual oxidation catalyst and in the presence of water, which is used in an amount comprised between about 1% and 25%, based on the weight of petrolatum.The acid products resulting from this oxidation reaction and their calcium soaps are anti-rust compounds.

Abstract: Disclosed is a process for the purification of a crude terephthalic acid product contaminated with up to 10% by weight of partially oxidized impurities including p-toluic acid and 4-carboxybenzaldehyde, comprising the steps of dissolving the crude product in water by heating up to a temperature at least about 5.degree. C. higher than necessary for having the resulting solution saturated with terephthalic acid; cooling the resulting solution down to a temperature not lower than about 185.degree. C. to precipitate purified crystals; recovering the purified crystals by solid-liquid separation at a temperature not lower than that used for the precipitation of the purified crystals; and washing the recovered crystals by contacting with water at a temperature which is at least as high as the temperature of the recovery step.

Abstract: The reaction mixture obtained by oxidizing p-xylene in the presence of water as diluent, at a temperature comprised between 140.degree. and 220.degree. C., and consisting of terephthalic acid crystals in suspension in an aqueous solution comprising unreacted p-xylene, intermediate oxidation products thereof, the heavy-metal catalyst and water is introduced in the upper part of a sedimentation column wherein the acid is separated by gravity and is washed with a counter current of water introduced near the bottom of said column, the temperature of the washing zone being higher than the minimum value T.sub.w given by the equation T.sub.w =144+0.225 T.sub.R, wherein T.sub.R is the oxidation temperature.