Abstract: There is provided a catalyst exhibiting a high activity and less catalytic deterioration, as well as a high selectivity, suitable for use in allowing aromatic hydrocarbons of 9 or more carbon atoms to react, and thereby converting them into toluene and aromatic hydrocarbons of 8 carbon atoms more useful as gasoline bases, and a conversion method using the catalyst. The catalyst is used for converting aromatic hydrocarbons of 9 or more carbon atoms in a material oil containing a component with a boiling point exceeding 210° C. into toluene and aromatic hydrocarbons of 8 carbon atoms in the presence of hydrogen, and contains a carrier containing one or more than one zeolites in which the maximum pore diameter of micropores is in a range of 0.6 to 1.0 nm; and one or more than one metals selected from the Group VIA metals of the Periodic Table or compounds thereof.

Abstract: A manufacturing process of a diesel gas oil with a high cetane number and a low sulfur, where the cetane number thereof is at least 45, the sulfur content thereof is less than 350 ppm, and the storage stability is superior, from a petroleum distillate oil with a low cetane number and a high sulfur content is provided.

Abstract: A process for the production of a low-sulfur diesel gas oil having a sulfur content of 0.05% by weight or lower and having a Saybolt color number of -10 or higher, from a petroleum distillate having a sulfur content of 0.1 to 2.0% by weight and having an inferior color and inferior oxidation stability comprises contacting the petroleum distillate with hydrogen in the presence of a hydro-treating catalyst which has at least one metal supported on said porous carrier, at a temperature of 350.degree. to 450.degree. C., and a pressure of 45 to 100 kg/cm.sup.2 in the first step to thereby produce materials having a sulfur content of 0.05% by weight or lower, and contacting further the materials issued from the first step with hydrogen in the presence of a hydro-treating catalyst which has at least one metal supported on said porous carrier, at a temperature of 200.degree. to 300.degree. C., and a pressure of 45 to 100 kg/cm.sup.2 in the second step to thereby produce the finished low-sulfur diesel gas oil.

Abstract: There is provided a method of selectively hydrogenating acetylenes in a C.sub.4 -hydrocarbon mixture containing butadiene for removing said acetylenes wherein a hydrogen containing gas and the liquid C.sub.4 -hydrocarbon mixture are continuously fed through the upper portion of a reactor filled with catalyst particles carrying one or more precious metals selected from the Group VIII elements of the Periodic Table, the hydrogen containing gas is present in the reactor forming a substantially continuous phase at the hydrogen partial pressure of less than 1.5 kg/cm.sup.2.a, while the C.sub.4 -hydrocarbon mixture is allowed to flow down over the surfaces of the catalyst particles in the liquid form and to react at 5 to 80.degree. C., and the reaction mixture is withdrawn through the bottom of the reactor.