Nippon Steel Chemical Co., Ltd.

Nobuyoshi Nakamura

Tadanori Hara

Yasuhiko Watanabe

Takuji Motegi

Yoshinori Kuriyama

This invention relates to the vapor-phase oxidation of hydrocarbons by passing a gaseous mixture comprising of a molecular oxygen-containing gas and hydrocarbons which may contain substituents to a fixed bed of catalyst and provides a process for vapor-phase oxidation to be effected by passing a gaseous mixture of raw materials to a fixed bed of catalyst in which the void ratio of the catalyst layers increases by stages in one step or more from upstream downward in the flow of the gaseous mixture of raw materials. For example, the process can oxidize in vapor phase such hydrocarbons as naphthalene, xylene, benzene, toluene, durene, butene, acenaphthene, anthracene, indene and their derivatives in high yields with high productivity. Moreover, the process can prepare phthalic anhydride in high yields with high productivity by the vapor-phase oxidation of naphthalene or ortho-xylene.

Gas-phase oxidization process and process for the preparation of phthalic anhydride

This invention discloses lightweight panels consisting of a honeycomb, boards on both sides, and phenolic foam of a density of 7-20 Kg/m.sup.3 in the cavities of the honeycomb and a method of making a honeycomb core, with the panels characterized by being light, fireproof, fire-resistant, thermally insulating, and of high strength and useful for building panels, particularly for panels in transportation equipment.

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Kitakyushu, Japan

Nobuyoshi Nakamura