A method for preparing methyl methacrylate from methacrolein and methanol; said method comprising contacting in a reactor a mixture comprising methacrolein, methanol and oxygen with a catalyst bed of heterogeneous catalyst comprising a support and a noble metal, wherein mass transfer rate of oxygen in hour.sup.1 divided by space-time yield in moles methyl methacrylate/kg.Math.catalyst hour in the catalyst bed is at least 20.

An apparatus for producing water-absorbing resin particles for which surface cross-linking treatment is conducted, the surface cross-linking treatment being conducted by spraying a surface cross-linking agent to a water-absorbing resin particle precursor and heating the agent and the precursor, the apparatus includes a treatment container in which the surface cross-linking treatment is conducted, a stirring device including a stirring member disposed in the treatment container, a heating device that heats an inside of the treatment container; and a spray nozzle disposed in the treatment container, the spray nozzle spraying into the treatment container the surface cross-linking agent supplied from a surface cross-linking agent supply source in an exterior of the treatment container through a supply pipe. In a flow path in the spray nozzle spanning from an entrance of the spray nozzle to a spray exit, a point whose opening cross-section is smallest in a flow path through which a fluid passes is the spray exit. A product with further stable physical properties can thereby be acquired.

Vortex arc reactor apparatus and method provide a nozzle with converging, throat, and diverging portions. Input structure inputs a reactant and an oxidant into the converging portion. Ignition structure ignites the input reactant and oxidant. A vortex-creating structure creates a vortex of the ignited reactant and oxidant in the converging portion. The input structure, the vortex-creating structure, and the nozzle converging and throat portions are configured to provide a throat-portion-vortex of ignited reactant and oxidant that has an angular velocity which provides (i) negatively-charged particles in an exterior portion of the throat-portion-vortex, (ii) positively-charged particles in an interior portion of the throat-portion-vortex, and (iii) at least one arcing reaction between the positively-charged particles and the negatively-charged particles, to form syngas and at least one aromatic liquid in the nozzle diverging portion. Gas/liquid separation structure is preferably configured to separate the formed syngas from the at least one aromatic liquid.

A hydrogenation method for increasing the yield of cyclohexane-1,4-dicarboxylic acid diisooctyl ester is provided. The hydrogenation method uses a hydrogenating reaction tank, which is equipped with a hollow-shaft gas-introducing mixer having air-extracting, air-exhausting and mixing functions, to allow hydrogen gas to be uniformly dispersed in a reaction solution. A ruthenium-on-alumina (Ru/Al.sub.2O.sub.3) hydrogenation catalyst can be used for carrying out a hydrogenation reaction under gentle conditions. Therefore, the hydrogenation catalyst can be used in a reduced amount, the risk of side reaction(s) can be reduced, and the yield of cyclohexane-1,4-dicarboxylic acid diisooctyl ester can reach at least 99% with a cis isomer proportion of at least 85.0%. The hydrogenation method shows extremely high economic benefit.

In order to suppress discharge of an unreacted content in a chemical reaction apparatus for irradiating a content with microwaves, a chemical reaction apparatus includes: a horizontal flow-type reactor in which a liquid content horizontally flows with an unfilled space being provided thereabove; a microwave generator that generates microwaves; and a waveguide that transmits the microwaves generated by the microwave generator to the unfilled space in the reactor, wherein the inside of the reactor is partitioned into multiple chambers to by overflow-type partition plates and that allow the content to flow thereover and an underflow-type partition plate that allows the content to flow thereunder.

An apparatus for producing water-absorbing resin particles for which surface cross-linking treatment is conducted by spraying a surface cross-linking agent to a water-absorbing resin particle precursor and heating the agent and the precursor, the apparatus includes a treatment container in which the surface cross-linking treatment is conducted, a stirring device including a stirring member disposed in the treatment container, a heating device that heats an inside of the treatment container; and a spray nozzle disposed in the treatment container, the spray nozzle spraying into the treatment container the surface cross-linking agent supplied from a surface cross-linking agent supply source in an exterior of the treatment container through a supply pipe. In a flow path in the spray nozzle spanning from an entrance of the spray nozzle to a spray exit, a point whose opening cross-section is smallest in a flow path through which a fluid passes is the spray exit.

The present invention consists in a reactor, a system and a method to process products such as polymers, where the reactor is formed by a vertical structure made up by a concentric ferrous inner tank and an external tank opened by the lower end, between which a jacket is arranged, where said reactor comprises: an upper lid; at least an inlet for material; an overhead valve in the at least inlet duct for material; at least one chimney; a stirring unit comprising a vertical axis connected to: a plurality of main blades fixed to it in a perpendicular way; a set of secondary blades perpendicularly joint to a sub-axis connected in angle to said vertical axis; a structure of lower blades; a discharge element comprising an opening and closing valve connected to a tray; and an air inlet located in one of the faces of the external tank.

A hydrogenation method for increasing the yield of cyclohexane-1,4-dicarboxylic acid diisooctyl ester is provided. The hydrogenation method uses a hydrogenating reaction tank, which is equipped with a hollow-shaft gas-introducing mixer having air-extracting, air-exhausting and mixing functions, to allow hydrogen gas to be uniformly dispersed in a reaction solution. A ruthenium-on-alumina (Ru/Al.sub.2O.sub.3) hydrogenation catalyst can be used for carrying out a hydrogenation reaction under gentle conditions. Therefore, the hydrogenation catalyst can be used in a reduced amount, the risk of side reaction(s) can be reduced, and the yield of cyclohexane-1,4-dicarboxylic acid diisooctyl ester can reach at least 99% with a cis isomer proportion of at least 85.0%. The hydrogenation method shows extremely high economic benefit.

A method for preparing methyl methacrylate from methacrolein and methanol; said method comprising contacting in a reactor a mixture comprising methacrolein, methanol and oxygen with a catalyst bed of heterogeneous catalyst comprising a support and a noble metal, wherein mass transfer rate of oxygen in hour.sup.1 divided by space-time yield in moles methyl methacrylate/kg.Math.catalyst hour in the catalyst bed is at least 20.

Process for reclaiming useful products from a waste oil, comprising a thermal separation step performed in a vessel at conditions, of temperature and pressure, allowing to substantially avoid cracking of the waste oil and to assure the separation of said heated waste oil into a first heavy oil fraction and into a second light oil fraction having, in comparison with the waste oil, a low content in solids and/or in other contaminants that are different from water and from inert gas. The process is further characterized in that while, during the thermal separation treatment, the waste oil is heated to a temperature about the boiling temperature of the heavy oil fraction, and below the cracking temperature of the waste oil, and at a pressure that is preferably below the atmospheric pressure, the heavy oil fraction of the vapours existing the vessel, in contact with a cooler surface, condenses and falls back into the vessel, while the second fraction, in a gaseous state, is eventually submitted to at least one further separation treatment. When water is present in the waste oil, said water is used to improve the amount of recovered light oils; and/or when no water is present in the waste oil, water or at least one inert gas or at least one component that may become an inert gas by heating may be added to the waste oil or to the thermal separation unit. Uses of the process for environmental applications and for treating used oils and to prepare oil products. Systems for reclaiming useful products from waste oils comprising at least one rotating kiln and at least one self-refluxing condenser and/or at least one dephlegmator.