Abstract: An object of the present invention is to provide a manufacturing process by which a pellet-shaped nonionic alkylene oxide resin can be obtained in a manner which is excellent in stability, economical efficiency and productivity and easy, wherein the pellet-shaped nonionic alkylene oxide resin, as a high-molecular material useful in a variety of applications, has a suitable molecular weight Mw and physical properties and is also excellent in the stability of the physical properties and further is also excellent in the handling property after the manufacture. As a means of achieving this object, the process for manufacturing a pellet-shaped nonionic alkylene oxide resin, according to the present invention, comprises the steps of: obtaining a nonionic alkylene oxide resin having fluidity by volatilizing a solvent from a nonionic alkylene oxide resin solution obtained in advance by solution polymerization; and then pelletizing the nonionic alkylene oxide resin having fluidity.

Abstract: The residual amount of a solvent in a water soluble nonionic alkylene oxide resin is decreased in an apparatus including an evaporation vessel and a stirring blade which scrapes-up and coats resin solution onto the inner wall surface of the evaporation vessel. A water soluble nonionic alkylene oxide resin having a crystallization temperature of 10 to 60° C. is extruded to a predetermined thickness in a molten state, the extruded molten resin is brought into contact with a metal surface which is at the crystallization temperature (Tc) or lower, and the thereby solidified resin may be cut into pellets. The resin pellets preferably are of rectangular shape and prescribed dimensions. The resin may be pulverized in a pulverizer by shearing force between a rotary blade and a fixed blade. In the pulverizer, grains smaller than a predetermined size pass through the screen, while larger grains are again pulverized.

Abstract: The present invention provides a production process, in which, when an ethylene oxide copolymer is obtained, conditions for obtaining this copolymer having a desirable molecular weight with ease and good reproducibility are provided. The production process for an ethylene oxide copolymer, according to the present invention, comprises the step of carrying out polymerization of a monomer mixture under stirring in a solvent, thereby obtaining the ethylene oxide copolymer, wherein the monomer mixture includes ethylene oxide and a substituted oxirane compound of a structural formula (1) as essential raw materials; with the production process being characterized in that the stirring is carried out by a stirring power of not less than 0.6 kW/m3.

Abstract: The present invention provides a novel production process for an ethylene oxide resin, in which, when the ethylene oxide resin is obtained, it is arranged that the resin should contain no antistatic agent, and further its water content is also easily controlled in not more than a definite amount, and the thermal damage of the above resin is prevented, and besides, the reduction of the cost can also be actualized. The production process for an ethylene oxide resin, according to the present invention, comprises the step of carrying out devolatilization of a solvent from a polymerization reaction liquid containing the solvent, thereby obtaining the ethylene oxide resin; with the production process being characterized by arranging that: after the devolatilization, the resin should have a solvent concentration of 0.01 to 30 weight % and a water content of not more than 200 ppm, and the resin should contain no antistatic agent.

Abstract: A reversely subliming substance is efficiently collected on a commercial scale from a gas containing the substance. This is achieved by introducing the gas containing the substance into a shell-and-tube collecting apparatus by controlling the resistance offered to the gas during the passage thereof through the cooled tubes retained inside the collecting apparatus or by utilizing gas-introducing tubes excelling in dispersibility.

Abstract: The present invention provides a production process, in which, when an ethylene oxide copolymer is obtained, conditions for obtaining this copolymer having a desirable molecular weight with ease and good reproducibility are provided. The production process for an ethylene oxide copolymer, according to the present invention, comprises the step of carrying out polymerization of a monomer mixture under stirring in a solvent, thereby obtaining the ethylene oxide copolymer, wherein the monomer mixture includes ethylene oxide and a substituted oxirane compound of a structural formula (1) as essential raw materials; with the production process being characterized in that the stirring is carried out by a stirring power of not less than 0.6 kW/m3.

Abstract: The present invention provides a novel production process for an ethylene oxide resin, in which, when the ethylene oxide resin is obtained, it is arranged that the resin should contain no antistatic agent, and further its water content is also easily controlled in not more than a definite amount, and the thermal damage of the above resin is prevented, and besides, the reduction of the cost can also be actualized. The production process for an ethylene oxide resin, according to the present invention, comprises the step of carrying out devolatilization of a solvent from a polymerization reaction liquid containing the solvent, thereby obtaining the ethylene oxide resin; with the production process being characterized by arranging that: after the devolatilization, the resin should have a solvent concentration of 0.01 to 30 weight % and a water content of not more than 200 ppm, and the resin should contain no antistatic agent.

Abstract: A method for producing crystals of pyromellitic dianhydride is disclosed which is characterized by setting the water content of an atmosphere used in handling the crystals of pyromellitic dianhydride at a temperature of not higher than 120° C. at a level of not more than 4 vol. %. Particularly by supplying an inert gas having a water content of not more than 4 vol. % to the step of production, it is made possible to prevent the conversion of pyromellitic dianhydride by hydration very efficiently.

Abstract: A method for producing crystals of pyromellitic dianhydride is disclosed which is characterized by setting the water content of an atmosphere used in handling the crystals of pyromellitic dianhydride at a temperature of not higher than 120° C. at a level of not more than 4 vol. %. Particularly by supplying an inert gas having a water content of not more than 4 vol. % to the step of production, it is made possible to prevent the conversion of pyromellitic dianhydride by hydration very efficiently.

Abstract: A reversely subliming substance is efficiently collected on a commercial scale from a gas containing the substance. This is achieved by introducing the gas containing the substance into a shell-and-tube collecting apparatus by controlling the resistance offered to the gas during the passage thereof through the cooled tubes retained inside the collecting apparatus or by utilizing gas-introducing tubes excelling in dispersibility.