Abstract: In a freeze-concentrating apparatus, an aqueous solution is cooled by a cooling cylinder 22 serving as a heat exchanger for cooling to continuously produce a suspension containing ice crystals. A liquid component is separated and discharged from the suspension to increase the ratio of the ice crystals, and the ice crystals are grown to produce a column-shaped ice cake. The ice cake is cut into an ice pillar of a given length and a concentrated solution is taken out from the ice pillar.

Abstract: Disclosed is an electrophotographic member containing as a charge transport material a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative which is remarkably excellent in solubility in an organic solvent and/or a binder such as polycarbonate resin, etc., can show very excellent electrophotographic properties such as high sensitivity, low residual potential and high durability. Further, a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative usable as a charge transport material, and a process for producing the same are disclosed. Furthermore, a fluorine-containing diarylamine usable for producing the fluorine-containing N,N,N',N'-tetraarylbenzidine derivative, and a process for producing the same are disclosed.

Abstract: Disclosed is an electrophotographic member containing as a charge transport material a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative which is remarkably excellent in solubility in an organic solvent and/or a binder such as polycarbonate resin, etc., can show very excellent electrophotographic properties such as high sensitivity, low residual potential and high durability. Further, a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative usable as a charge transport material, and a process for producing the same are disclosed. Furthermore, a fluorine-containing diarylamine usable for producing the fluorine-containing N,N,N',N'-tetraarylbenzidine derivative, and a process for producing the same are disclosed.

Abstract: Disclosed is an electrophotographic member containing as a charge transport material a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative which is remarkably excellent in solubility in an organic solvent and/or a binder such as polycarbonate resin, etc., can show very excellent electrophotographic properties such as high sensitivity, low residual potential and high durability. Further, a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative usable as a charge transport material, and a process for producing the same are disclosed. Furthermore, a fluorine-containing diarylamine usable for producing the fluorine-containing N,N,N',N'-tetraarylbenzidine derivative, and a process for producing the same are disclosed.

Abstract: A process for producing an aromatic dicarboxylic acid which comprises subjecting a "K-region" arene to liquid phase oxidation with hydrogen peroxide in a water-insoluble organic solvent in the presence of a tungsten compound and a phase transfer catalyst and optionally a mineral acid.

Abstract: A polyoxyalkylene carbazole adduct represented by the following formula I: ##STR1## wherein R stands for at least one member selected from the group consisting of H, CH.sub.3 and C.sub.6 H.sub.5, R' for at least one member selected from the group consisting of CH.sub.3, C.sub.6 H.sub.5 and H, (providing that R' is at least one member selected from the group consisting of CH.sub.3 and C.sub.6 H.sub.5 when R is H, and R is at least one member selected from the group consisting of CH.sub.3 and C.sub.6 H.sub.5 when R' is H), n for an integer of the value of 0 to 500, m for an integer of the value of 0 to 500, and n+m for an integer of the value of 2 to 1000.