Abstract: A process for preparing substantially purified aqueous indole solution. In the process of the present invention, crude indole containing an organic impurity is dissolved in an organic solvent which is immiscible with water, the distribution ratio of the impurity to the organic phase, when two-phase liquid system is formed with the organic solvent and an aqueous medium, being greater than that of indole; and the indole solution is contacted with water or an aqueous reaction medium for conducting the reaction to form two-phase liquid system and to distribute indole to the aqueous phase.

Abstract: An aqueous solution containing amino acids of which the solubility in water at isoelectric point is low, can be highly concentrated by means of semipermeable membranes in the presence of a water-soluble organic solvent while increasing the solubility by adjusting a pH.

Abstract: Enzyme-containing granules are produced by forming drops of a gellable enzyme-containing liquid with a rotating disc and bringing the drops in contact with a gelling solution. The disc is preferably contained in a column, and the gelling solution flows down walls of the column to a reservoir in a lower legion of the column. Drops of the enzyme-containing liquid from the rotating disc contact the gelling solution while flowing down the walls and are carried to the reservoir. Preferably, the enzyme-containing liquid is an aqueous alginate solution containing the enzyme and the gelling solution is an aqueous calcium chloride solution.

Abstract: In an industrial process for preparing indole by reacting aniline and ethylene glycol, high boiling-point impurities and non-volatile substances are removed in advance from the reaction mixture either before the recovery of aniline from the reaction mixture or before the subsequent rectification of the resultant indole. Indole of a high purity can thus be obtained.

Abstract: A process for producing an indole which comprises reacting an aniline and a diol in the presence of a catalyst to produce a reaction mixture containing the indole, unreacted aniline and by-products, condensing the reaction mixture to obtain a liquid reaction product, recovering the unreacted aniline from the liquid reaction product, reducing the contents of specified by-products in the recovered aniline below specified levels and reutilizing the resulting recovered aniline. To reduce the contents of the specified by-products in the recovered aniline below specified levels, it is preferred to subject the liquid reaction product or an aniline fraction separated therefrom to a heat-treatment and then to distillation. In the above manner, the recovered aniline can be reutilized in the reaction without causing the activity of the catalyst to deteriorate.

Abstract: A process for the liquid phase oxidation of an organic substance-containing effluent which comprises subjecting said effluent to a liquid phase oxidation treatment in the presence of a copper catalyst at a copper ion concentration of 50-5000 ppm and also in presence of an ammonium ion concentration of five or more times the copper ion concentration thereby to oxidize the organic substances in the effluent, and recovering the copper catalyst from the treated effluent for reuse. The recovery of the copper catalyst may be effected either by a process in which the copper catalyst is separated as a precipitate or by a process using a resin adsorption.