Abstract: An improved process for preparing a hydroxyl-amine salt by reduction of a solution of nitrate ions or nitrogen monoxide. Dissolved molybdenum in amounts as low as about two milligrams per liter of nitrate/nitrogen monoxide solution are known to interfere with the reduction reaction. The present invention provides a simple method of reducing molybdenum contamination, and hence enhancing the efficiency of the reduction reaction. Dissolved molybdenum is removed from the nitrate/nitrogen monoxide solution by coprecipitation with a complex iron-ammonium phosphate. If chromium is present, it will also be removed by this coprecipitation.

Abstract: A process for recovering substantially pure .epsilon.-caprolactam from a contaminated solution thereof is disclosed by concentrating, if needed, the caprolactam content of the solution to about 60-75 weight percent then extracting the concentrated solution with an organic solvent such as benzene or the like, then recovering the resulting caprolactam-laden organic solution.

Abstract: In commercial processes for producing epsilon-caprolactam, the caprolactam product is in admixture with sulfuric acid. An improved process for removing sulfuric acid from the caprolactam results from treating the admixture with ammonia at superatmospheric pressure.

Abstract: An improved cyclic process for producing cyclohexanone oxime is provided wherein the circulating reaction medium is subjected to a heat treatment, at a temperature of at least 120.degree. C in the presence of nitrous gases, and at an absolute pressure of over 1 atmosphere, as it circulates between the oxime synthesis zone and the hydroxylamines synthesis zone. Cyclohexanone oxime is a valuable commercial commodity e.g. for the preparation of nylon-6 via .epsilon.-caprolactam.

Abstract: An improved cyclic process for producing cyclohexanone oxime is provided wherein the circulating reaction medium is subjected to a heat treatment of at least 40.degree.C in the presence of nitrous gases as it circulates between the oxime synthesis zone and the hydroxylamine synthesis zone. The residual cyclohexanone oxime is hydrolyzed to cyclohexanone in said heat treatment in the presence of nitrous gases. The reaction medium is then stripped of cyclohexanone prior to recirculating to the hydroxylamine synthesis zone. In another embodiment of the invention the recirculating reaction mixture is heated to at least 50.degree.C in the presence of nitrous acid as the mixture circulates between the oxime synthesis zone and the hydroxylamine synthesis zone, thus reducing the amount of residual cyclohexanone oxime and cyclohexanone to an insignificant amount.

Abstract: Organic sulfoxides such as dimethylsulfoxide are used in the transformation of alicyclic ketoximes into the corresponding lactams according to the Beckmann rearrangement in the presence of a strong acid cation exchange resin as disclosed. Thus cyclohexanone is dissolved in DMSO and contacted with a sulfonated copolymer of styrene and divinyl benzene to produce caprolactam in a continuous process.

Abstract: Polymerizable quality .epsilon.-caprolactam having an alkalinity of less than 0.05 meq. per kg. of lactam is produced in the improved disclosed process which includes extracting an aqueous lactam-rich solution with an organic solvent having a high distribution coefficient for the lactam with respect to the aqueous solution, and evaporating the lactam-rich organic solvent solution and recovering by distillation the lactam. Evaporation of the organic solvent requires considerably less thermal energy than evaporation of a similar aqueous solution.

Abstract: An improved recycle process for the production of cyclohexanone oxime comprising circulating an acidic, aqueous solution containing phosphoric acid or ammonium bisulphate or a mixture thereof between a hydroxylamine synthesis zone and a cyclohexanone oxime synthesis zone. Nitrate ions are added to the aqueous solution just prior to the hydroxylamine synthesis zone and catalytically reduced with molecular hydrogen. The aqueous solution from the hydroxylamine synthesis zone is then fed to the cyclohexanone oxime synthesis zone along with a ketone. The aqueous solution is then separated from the oxime formed, either (a) treated at an elevated temperature for a sufficient time to decompose any trace amounts of oxime and cyclohexanone or (b) subjected to a stripping step to remove any trace amounts of oxime and cyclohexanone before being recirculated to the hydroxylamine synthesis zone. The oxime formed by this process is a valuable commercial commodity.