Abstract: A process for the continuous preparation of aniline by hydrogenating nitrobenzene with hydrogen is disclosed which comprises the steps of suspending, in an aniline solvent, a catalyst of palladium or palladium-platinum which is deposited on a lipophilic carbon having an oil absorbency of at least 100, and carrying out reaction at a temperature of from 150.degree. to 250.degree. C. substantially in the absence of water while aniline and water formed in said reaction are continuously distilled off as vapor from the reaction product, and the concentration of nitrobenzene in the reaction solution is maintained at 0.01% by weight or less, wherein a zinc compound is added to the reaction system as a promotor and carbon monoxide is added to the hydrogen at a concentration of 1-500 ppm.

Abstract: A novel polythiol having four or more functional groups, a process for producing the polythiol comprising reacting thiourea with a specific compound, a sulfur-containing urethane-based resin prepared from the polythiol and a lens made of the resin. The resin has a high refractive index, and low dispersion of refractive index, is lightweight, colorless and transparent, has no optical distortion, and has excellent characteristics in weatherability, dye-affinity, heat resistance, impact resistance and machinability.

Abstract: One aspect of the present invention relates to a process for preparing plastic lenses having a high-refractive index comprising forming a mixture containing one or more polyisocyanate compounds; one or more active hydrogen compounds selected from the group consisting of a polyol compound having no sulfur atom, a polyol compound having at least one sulfur atom, and a polythiol compound having at least one sulfur atom in addition to the sulfur atom contained in mercapto group and at least one internal releasing agent and then casting and polymerizing the mixture.

Abstract: A novel bis-urea compound, preparation process of the compound, and preparation process of 1,3-dialkyl-2-imidazolidinone are disclosed and the disclosure provides a novel preparation process of 1,3-dialkyl-2-imidazolidinone and simultaneously enables effective utilization of N,N',N"-trialkyldiethylentriamine which lacks a large amount use and is desired to develop new application.

Abstract: A novel bis-urea compound, preparation process of the compound, and preparation process of 1,3-dialkyl-2-imidazolidinone are disclosed and the disclosure provides a novel preparation process of 1,3-dialkyl-2-imidazolidinone and simultaneously enables effective utilization of N,N',N"-trialkyldiethylentriamine which lacks a large amount use and is desired to develop new application.

Abstract: A process for the preparation of 4-methoxy-2,2',6-trimethyldiphenylamine, which comprises heating and reacting 2,6-dimethylcyclohexanone and 2-methyl-4-methoxyaniline in the presence of a dehydrogenation catalyst while removing the resultant hydrogen and water from the reaction system.

Abstract: A processes for the preparation of diphenylamine or a nucleus-substituted derivative thereof, which comprise, upon feeding into a reaction system a phenol compound and reacting in the reaction system a cyclohexanone compound with an aniline compound in the presence of a hydrogen transfer catalyst and a catalytic amount of the cyclohexanone compound corresponding to the phenol compound while using the phenol compound as a hydrogen acceptor and forming the cyclohexanone compound in the reaction system, (1) conducting reaction while adding dropwise the aniline compound and (2) employing a hydroxide, carbonate or bicarbonate of an alkali metal and/or alkaline earth metal when the hydrogen transfer catalyst is one of noble metals of Group VIII of the periodic table, respectively.

Abstract: Disclosed are (1) a method for preparing an aromatic secondary amino compound which comprises reacting an N-cyclohexylideneamino compound in the presence of a hydrogen moving catalyst and a hydrogen acceptor by the use of a sulfur-free polar solvent and/or a cocatalyst, and (2) a method for preparing an aromatic secondary amino compound which comprises reacting cyclohexanone or a nucleus-substituted cyclohexanone, an amine and a nitro compound corresponding to the amine in a sulfur-free polar solvent in the presence of a hydrogen moving catalyst, a cocatalyst being added or not added. In a further aspect, a method is provided for the preparation of aminodiphenylamine by reacting phenylenediamine and cyclohexanone in the presence of a hydrogen transfer catalyst in a sulfur-free polar solvent while using nitroaniline as a hydrogen acceptor.

Abstract: A process is provided for the preparation of an aliphatic polyisocyanate. Upon reacting an aliphatic polyamine or its hydrochloride or carbonate with phosgene in an inert liquid medium, the reaction is conducted while charging an inert gas into a reaction system.

Abstract: The present invention relates to 1,3,6-Trialkylhexahydro-1,3,6-triazocine-2-on represented by the formula (1): ##STR1## wherein R is a C.sub.1 .about.C.sub.8 alkyl group and a preparation process of the compound comprising reacting N,N',N"-trialkyldiethylenetriamine represented by the formula (2): ##STR2## wherein R is a C.sub.1 .about.C.sub.8 alkyl group, with urea, phosgene or carbon dioxide.

Abstract: A diphenylamine with both the phenyl groups being substituted is prepared by reacting a phenol with ammonia in the presence of a hydrogen transfer catalyst and a cyclohexanone; or by converting a portion of the phenol to the cyclohexanone in the presence of a hydrogen transfer catalyst and under hydrogen pressure and then reacting the remaining portion of the phenol with ammonia in the presence of the cyclohexanone so converted and the hydrogen transfer catalyst. The diphenylamine can be obtained very efficiently.

Abstract: An internal release agent comprises a sulfur-containing acid phosphoric esters selected from the group consisting of thiophosphoric acid esters and dithiophosphoric acid esters of the formula, ##STR1## where X and Y are independently selected from the group consisting of an oxygen atom and a sulfur atom, at least one of X and Y is a sulfur atom, and R.sub.1 and R.sub.2 are independently alkyl groups.

Abstract: Disclosed are(1) a method for preparing an aromatic secondary amino compound which comprises reacting an N-cyclohexylideneamino compound in the presence of a hydrogen moving catalyst and a hydrogen acceptor by the use of a sulfur-free polar solvent and/or a cocatalyst, and(2) a method for preparing an aromatic secondary amino compound which comprises reacting cyclohexanone or a nucleus-substituted cyclohexanone, an amine and a nitro compound corresponding to the amine in a sulfur-free polar solvent in the presence of a hydrogen moving catalyst, a cocatalyst being added or not added.

Abstract: Disclosed is a method for extracting an amino acid ester from a hydrous solution which comprises adding thereto a water-insoluble organic solvent and then an amount of a base effective to liberate only a portion of the amino acid ester in free base form, and transferring the thus liberated amino acid ester in the free base form into the organic layer, and repeating the neutralization-extraction steps until all of the amino acid ester has been extracted.

Abstract: A method for stabilizing an isocyanate compound by adding 10-5000 ppm of phenol to the isocyanate compound, and also an isocyanate composition so stabilized. In the isocyanate composition stabilized by the above method, coloring due to time-dependent changes and the occurrence of turbidity through self-polymerization are both suppressed so that it shows outstanding storage stability compared with a corresponding isocyanate composition containing a conventional stabilizer.

Abstract: A preparation process of a bis(3-nitrophenoxy) compound represented by the formula: ##STR1## wherein X is a direct bond, divalent hydrocarbon having from 1 to 10 carbon atoms or a divalent group selected from --C(CF.sub.3).sub.2, --CO--, --S--, --SO--, SO.sub.2 --or --O--, which comprises reacting 4,4'-bisphenol with m-dinitrobenzene in the presence of an alkali metal carbonate or alkali metal hydrogen carbonate having a particle size of 250 .mu.m or less while removing generated water from the reaction system during the reaction. In one embodiment of the process, the reaction is carried out while simultaneously adding 4,4'-bisphenol and m-dinitrobenzene to a reaction vessel which was previously charged with the base and an aprotic polar solvent.

Abstract: A process for the continuous preparation of aniline by hydrogenating nitrobenzene is disclosed which comprises the steps of suspending, in an aniline solvent, a catalyst of palladium or palladium-platinum which is deposited on a lipophilic carbon having an oil absorbency of at least 100, adding a zinc compound and an alkali metal carbonate or a zinc compound and an alkali metal bicarbonate as promotors to the reaction system, and carrying out reaction at a temperature of from 150 to 250.degree. C. substantially in the absence of water while aniline and water formed in said reaction are continuously distilled off as vapor from the reaction product, and the concentration of nitrobenzene in the reaction solution is maintained at 0.01% by weight or less.

Abstract: Optical urethane resins according to the present invention are each obtained by reacting an active hydrogen compound with an isocyanate compound containing as a stabilizer a phenolic compound. Owing to their low yellowness, high light transmittance and optical-strain-free quality, these resins are useful as optical materials for plastic lenses or the like which are required to be colorless, transparent and uniform.

Abstract: This invention is an industrially efficient and improved process for the preparation of aliphatic polyisocyanates by using esters as the solvent for converting aliphatic polyamines to isocyanates.

Abstract: The present invention relates to a process for producing a plastic lens having a high refractive index and profile regularity comprising forming a mixture of one or more of sulfur-containing aromatic polyisocyanate compounds, one or more of active hydrogen compounds selected from the group consisting of polyol compounds and polythiol compounds, and at least one internal mold releasing agent, and subjecting the resulting mixture to casting polymerization, and a plastic lens obtained according to the process.