Abstract: An apparatus for quenching pyrolysis gas, in which cooling of pyrolysis gas of hydrocarbons can be carried out very rapidly, decoking of pyrolysis furnace can be carried out easily and the life of apparatus can be extremely extended, is provided according to the apparatus in which the upper outlet of each of cracking tubes of a multi-tubular pyrolysis furnace for hydrocarbons is connected directly with each of vertical introducing pipes for pyrolysis gas, having a diameter larger than that of said upper outlet, and situated on a level upper than that of said upper outlet; cooling pipes for pyrolysis gas having closed lower ends are inserted in said introducing pipes in the same direction therewith; pipes for flowing-in a cooling medium, the lower ends of which pipes open into said cooling pipes at the position close to the closed ends of the cooling pipes are provided and opening parts for each of fluids are provided in the neighborhood of the upper ends of said introducing pipes and said cooling pipes, respe

Abstract: Polycarbonate oligomer having uniform qualities is prepared by reacting an aqueous alkaline solution of 2,2-(4,4'-dihydroxydiphenyl) propane with phosgene in the presence of methylene chloride and as a characteristic point of this method, in the presence of an inert gas in an amount of 1 to 10 mol % based upon the phosgene.

Abstract: In the method for producing a high impact polystyrene from a monomer of styrene or/and its derivative and a rubbery polymer as reactants, an improvement is provided which comprises passing said reactants through a tubular reactor having parts where the passage way of flow of said reactants is constricted, while keeping said reactants in a laminar flow as much as possible in the parts other than said parts, in a first stage polymerization to prepare a reacted mixture containing a prepolymer until the conversion of monomer to polymer becomes 10 to 60%, and subjecting the resulting reacted mixture to a second stage polymerization in the state where almost no shearing is exerted thereupon.The shearing during said first stage polymerization can be uniformly carried out.The resulting product has superior high impact properties.

Abstract: A method for rapid cooling of high temperature reaction gases obtained by ermal cracking of hydrocarbons, which comprises conducting an indirect heat exchange between a high temperature reaction gas obtained by thermal cracking of a hydrocarbon and a molten metal maintained at a prescribed temperature, lest heavy components in the high temperature gas be substantially condensed. In this method, the molten metal can be circulated by the use of a pressurized inert gas. In practice of this method, there can be effectively used a high temperature reaction gas cooling apparatus comprising a double-tubular heat exchanger, a cooling tank connected to said heat exchanger, and an inert gas circulating passage connected to a conduit connecting said heat exchanger and said cooling tank.