Abstract: Pure 1,4-dihydroxy-2-arylnaphthoate is prepared in high yield by allowing 1,4-dihydroxy-2-naphthoic acid to react with triarylphosphite in the presence of an acid catalyst selected from organic and inorganic acids and crystallizing from a mixed solvent consisting essentially of lower alcohols and water until 1,4-dihydroxy-2-naphthoic acid is isolated and is further purified by crystallization from a mixed solvent consisting essencially of lower alcohols, water and extraction solvent, i.e., alkyl-substituted aromatic hydrocarbons or halogen-substituted aliphatic or aromatic hydrocarbons.

Abstract: Pure 1,4-dihydroxy-2-arylnaphthoate is prepared in high yield by allowing 1,4-dihydroxy-2-naphthoic acid to react with triarylphosphite in the presence of an acid catalyst selected from organic and inorganic acids and crystallizing from a mixed solvent consisting essentially of lower alcohols and water until 1,4-dihydroxy-2-naphthoic acid is isolated and is further purified by crystallization from a mixed solvent consisting essentially of lower alcohols, water and extraction solvent, i.e., alkyl-substituted aromatic hydrocarbons or halogen-substituted aliphatic or aromatic hydrocarbons.

Abstract: A stabilized resin composition comprising a resin, a piperidine derivative represented by the formula (III) ##STR1## wherein R.sub.1 is a hydrogen atom or an alkyl group having 1 to 3 carbom atoms; R.sub.2 is a hydrogen atom or an alkyl group having from 1 to 2 carbon atoms; and R.sub.3 and R.sub.4 are each independently an alkyl group having 1 to 12 carbon atoms, a phenol-type antioxidant and a sulfur-containing antioxidant. The composition simultaneously meets heat resistance, oxidation resistance and light resistance requirements.

Abstract: 2,4-Dichloro-3-alkyl-6-nitrophenol, which is a precursor of 2,4-dichloro-3-alkyl-6-aminophenol useful for the production of a cyan coupler to be used with a sensitive material in the field of a photography in color, is industrially advantageously produced by (a) nitration of 2,4,5-trichloro-3-alkylbenzene, followed by hydrolysis of the resulting 2,4,5-trichloro-3-alkyl-6-nitrobenzene, or (b) hydrolysis of 2,4,5-trichloro-3-alkylbenzene-6-sulfonic acid or a salt thereof, followed by nitration of the resulting 2,4-dichloro-3-alkylphenol-6-sulfonic acid or a salt thereof, the starting material usable for these processes being 4-alkylbenzenesulfonic acid or a salt thereof, which is easily available.

Abstract: A stabilizer for synthetic resins containing as an effective ingredient a hindered piperidine compound represented by the general formula: ##STR1## wherein R.sub.1 represents a C.sub.1 -C.sub.18 alkyl group, R.sub.2 represents a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group, n represents an integer of 1 to 12, and C.sub.n H.sub.2n represents a straight-chain or branched alkylene group.

Abstract: Piperidine derivatives represented by the general formula (1) ##STR1## (wherein R.sub.1 is a hydrogen atom, an alkyl group of 1 to 3 carbon atoms or an acyl group of 2 to 18 carbon atoms; and k, m and n each are independently an integer of 1 to 3), a process for producing said derivatives, and stabilizers for organic substances containing said derivatives as an active component.

Abstract: A method for purifying 1-aminoanthraquinone which comprises previously subjecting a crude 1-aminoanthraquinone to a removal treatment of inorganic impurities so that their content is reduced to not more than 4 wt. % as converted to ash basis or to a removal treatment of iodine-consuming reductive inorganic impurities so that their content is reduced to not more than 2 wt. % as converted to consumed iodine basis, and then rectifying the 1-aminoanthraquinone.

Abstract: The present invention relates to a piperidine derivative represented by the general formula (I), ##STR1## wherein R.sub.1 is a uni- or divalent carboxylic acid residue, R.sub.2 is a hydrogen atom or a C.sub.1 -C.sub.3 alkyl or C.sub.1 -C.sub.18 acyl group, l is an integer of 1 to 3 and n is 1 or 2,its production and a stabilizer for organic substances containing it as an effective ingredient.

Abstract: The present invention relates to a piperidine derivative represented by the general formula (I), ##STR1## wherein R.sub.1 and R.sub.2 independently represent a hydrogen atom or a C.sub.1 -C.sub.3 alkyl or C.sub.2 -C.sub.20 acyl group, R.sub.3 represents a hydrogen atom or a C.sub.1 -C.sub.20 alkyl, C.sub.6 -C.sub.20 aryl, C.sub.7 -C.sub.20 aralkyl or C.sub.2 -C.sub.20 acyl group, and l represents 1 to 3, and a stabilizer for organic substances containing said piperidine derivative as an effective ingredient.

Abstract: A high melting, high boiling organic compound is easily and stably purified by continuously supplying the molten organic compound to a rectification zone under a subatmospheric pressure and continuously distilling off and recovering vapors from the top of the rectification zone, while continuously withdrawing bottoms containing higher boiling impurities and/or involatile impurities than the desired compound from a reboiling zone at the bottom of the rectification zone to the outside of rectification system by means of a barometric leg, without any pretreatment of removing lower boiling impurities therefrom before the rectification, and without disturbing a pressure balance in the rectification system.

Abstract: A process for producing 2-hydroxynaphthalene-3-carboxylic acid comprising reacting carbon dioxide with a homogeneous liquid mixture comprising an alkali metal salt of .beta.-naphthol, .beta.-naphthol and a specific alkylbenzene is disclosed.