A Study on Byproducts in the High-Pressure Melamine Production Process.

The industrial production of melamine is carried out by the thermal decomposition of urea in two technological processes, using high or low pressure. The reaction may be accompanied by the formation of undesirable byproducts, oxoaminotriazines, and so-called polycondensates, mainly melam, melem, and melon, as well as their hydrates and adducts. Their presence leads to the deterioration of the quality of the final product and may lead to the release of troublesome deposits inside the apparatus of the product's separation node.

Selective Oxidation of Cyclohexanone to Adipic Acid Using Molecular Oxygen in the Presence of Alkyl Nitrites and Transition Metals as Catalysts.

This paper presents a not previously reported catalytic system consisting of transition metals Co and Mn and alkyl nitrites R-ONO for the oxidation of cyclohexanone with oxygen to adipic acid. The influence of type and amount of catalyst, temperature, time, and type of raw material on conversion and product composition were determined. In addition, the oxidation of selected cyclic ketones such as cyclopentanone, cyclohexanone, cyclooctanone, cyclododecanone, 2-methylcyclohexanone, 3-methylcyclohexanone, and 4-methylcyclohexanone in acetic acid as solvent was performed.

Oxidation of Cyclohexane/Cyclohexanone Mixture with Oxygen as Alternative Method of Adipic Acid Synthesis.

Herein, an alternative method for adipic acid (AA) synthesis of industrial importance has been reported. The proposed novel method involves the one-step, solvent-free oxidation of a cyclohexane/cyclohexanone (CH/CH=O) mixture, with a cheap oxidizing agent such as O or air under mild conditions in the presence of -hydroxyphtalimide (NHPI) and transition metals as catalysts. It has been showed that CH/CH=O mixture under applied mild conditions oxidized faster than CH and CH=O separately.

Oxidation of Cyclohexanone with Peracids-A Straight Path to the Synthesis of ε-Caprolactone Oligomers.

During Baeyer-Villiger (BV) oxidation of cyclohexanone with peracids, oligo(ε-caprolactone) (OCL) may be formed. In this work, a two-step one-pot method for the synthesis of OCL involving the BV oxidation of cyclohexanone with peracids and then oligomerization of the resulting ε-caprolactone has been developed. The process was carried out in two solvents: toluene and cyclohexane.

Recent Developments in Lactone Monomers and Polymer Synthesis and Application.

Lactones are a group of compounds that have been known for several decades. The commercial importance of lactones results from the possibility of manufacturing of a broad scope of derivatives and polymers with a wide spectrum of applications. In this work the synthesis and characterization of simple lactones are described, which due to the easy methods of the synthesis are of high importance for the industry.

Perdecanoic acid as a safe and stable medium-chain peracid for Baeyer-Villiger oxidation of cyclic ketones to lactones.

Stability studies dedicated to high-energy compounds for a series of linear peracids (C-C), including sensitivity to mechanical impulse (shock and friction), as well as electrical (spark) and thermal sensitivity (temperature and heat of decomposition), were presented in this work for the first time. Studies revealed that all peracids were insensitive to shock, while in the case of the other sensitivity tests sharp differences between results for C and C peracids were observed. Taking into account the relatively high initial temperature of decomposition (above 64 °C) perdecanoic acid was selected as a safe alternative to commonly used hazardous short-chain peracids.