Abstract: A process for producing a mesophase pitch by heating a carbonaceous pitch at 350.degree. to 550.degree. C. wherein the heat treatment is conducted while supplying a hydrogen donor to the pitch. The mesophase pitch thus produced has an excellent spinnability.

Abstract: Mesophase pitch containing quinoline soluble mesophase is produced from a pitch having a specific aromatic hydrogen content with a short heat treatment time without conducting any special treatment such as extraction.

Abstract: A process for producing an alkenyl-substituted aromatic compound which comprises catalytically reacting an alkyl-substituted aromatic compound in the vapor phase in the presence of molecular oxygen and a catalyst composed of palladium metal and a metal halide compound supported on an alumina carrier to convert it to the corresponding alkenyl-substituted aromatic compound, wherein said reaction is carried out in the presence of a catalyst composed of palladium metal and a metal halide compound supported on a carrier consisting substantially of .alpha.-alumina.

Abstract: A process for producing a halobiphenyl derivative represented by the following formula (I) comprises dehydrogenating a cyclohexylhalobenzene represented by the following formula (II) under such conditions that substantially no dehalogenation occurs. ##STR1## wherein X represents a halogen atom, and each of R.sup.1 and R.sup.2 independently represents a group represented by the formula ##STR2## wherein A represents carboxyl or an alkoxycarbonyl group and R represents a hydrogen atom or a lower alkyl group; an alkylcarbonyl; alkenyl; alkynyl; alkyl; aryl; arylcarbonyl; hydroxyalkyl; cyanoalkyl or cyanoalkenyl group.

Abstract: A process for preparing corresponding alkyl-substituted aromatic compounds by the gas phase catalytic dehydrogenation of vinylcycloalkenes in the presence of a dehydrogenation catalyst supported on a carrier, said catalytic dehydrogenation being carried out(i) in the presence of a dehydrogenation catalyst in which at least one of elements belonging to periods 5 and 6 in the group VIII of the periodic table selected from the group consisting of palladium, rhodium, platinum, iridium and ruthenium is supported on active carbon(ii) by introducing steam into the reaction system,(iii) but without introducing hydrogen into the reaction system,(iv) at conditions of temperatures ranging from 300.degree. C. to less than 350.degree. C. and pressure less than 2.5 atm (absolute pressure),wherein a liquid hourly space velocity (LHSV) is set at about 5 hr.sup.-1 or less when the catalytic dehydrogenation is effected in the presence of said catalyst in which palladium alone is supported on active carbon.