Abstract: To provide a filter for highly viscous fluid permitting a foreign matter in a supporting layer to be easily removed and its final layer to be directly washed, a method for efficiently producing a refined polymer by using said filter and a method for producing moldings by molding said refined polymer.

Abstract: A process for purifying and recovering phenol present in a mixed solution containing phenol and one or more compounds capable of forming azeotropic mixtures with phenol wherein an additive which is at least one compound belonging to the following groups 1 to 5 is added to the mixed solution and the resulting mixture is distilled:group 1: dialkylene glycols having 2-10 carbon atoms, polyalkylene glycols having 2-10 carbon atoms, and the ethers thereof,group 2: alkanediols having 2-20 carbon atoms,group 3: ethanolamine-type compounds represented by the formula (1) shown below,group 4: lactam compounds represented by the formula (2) shown below,group 5: quinoline, sulfolane, and N,N-dimethylimidazolidinone, ##STR1## wherein R.sub.1 represents an alkyl group having 1-6 carbon atoms, a cycloalkyl group having 1-6 carbon atoms, a monohydroxyalkyl group having 1-6 carbon atoms or a hydrogen atom, m represents an integer of 1-4, and X represents a hydroxyl group, an amino group or a hydrogen atom provided that R.sub.

Abstract: A process for preparing an N-alkyl-substituted aminophenol is disclosed, comprising continuously feeding an aldehyde or a ketone to a reaction system containing an organic solvent, a catalyst for reduction, hydrogen, and an aminophenol to conduct a reductive alkylation reaction, wherein said reductive alkylation reaction is carried out while continuously adding an organic carboxylic acid into the reaction system. The process attains a high yield even when the catalyst is repeatedly used and does not cause corrosion of equipment.

Abstract: A process for preparing an N-alkylaminophenol is disclosed, comprising subjecting an aminophenol to reductive alkylation with an aldehyde or a ketone in the presence of an organic solvent and hydrogen, wherein the reductive alkylation is carried out at a temperature of from 20.degree. to 70.degree. C. in the further presence of a catalyst for reduction comprising platinum and at least one metal element selected from metal elements belonging to the IB group, IIB group, IVB group, VB group, and VIB group of the Periodic Table, supported on activated carbon, or comprising palladium and at least one metal element selected from metal elements belonging to the IB group, IIB group, IVB group, VB group and VIB group of the Periodic Table, supported on activated carbon.