Five ionic liquids based on a quaternary ammonium core substituted with a D-glucose moiety and alkyl chains of varying length were synthesized as prospective phase-transfer catalysts. The catalytic activity of the obtained ionic liquids was tested in the dehydrochlorination of 3,4-dichloro-1-butene to chloroprene. The reaction proceeded in a two-phase system in the presence of an aqueous solution of sodium hydroxide. The results showed that the longer the alkyl chain in the cation, the higher the activity of the ionic liquid as a phase-transfer catalyst. The tested ionic liquids gave an easily recyclable system compared to classical phase-transfer catalysts that were soluble in the reaction system, with no leaching observed over five cycles (chloroprene yield >99%). The cytotoxicity and biodegradability of a series of synthesized ionic liquids based on D-glucose were determined so that a preliminary hazard assessment could be undertaken.
This paper reports cyclopentane, cyclohexane and cyclooctane oxidation in the presence of N-hydroxyphthalimide or 4-dodecyloxycarbonyl-N-hydroxyphthalimide in combination with Co(II) and Fe(II) salts using O 2 /CO 2 mixture (0.5 MPa O 2 , 9.5 MPa CO 2 ). The studies demonstrated that the application of scCO 2 in cyclohexane and cyclooctane oxidation processes results in higher conversion and yield of respective ketone and alcohol in comparison to processes performed using air under pressure (0.7 MPa).Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Nicotinic acid is a naturally occurring pyridine carboxylic acid, contained in vitamin PP, an essential nutrient for humans and animals, and used as an antipelagic agent. Nicotinic acid can be made from tryptophan by plants and animals but is usually not completely bioavailable. Industrially, nicotinic acid is produced mainly by oxidation of 5-ethyl-2-methylpyridine with nitric acid. One of the by-products of the process is nitrous oxide, a gas that is difficult to recycle and manage, with a greenhouse effect 300 times stronger than CO2. A new technology for the industrial production of nicotinic acid is undoubtedly necessary to meet the needs of green chemistry and not burden the environment. We carried out a literature review on ecological methods to produce nicotinic acid from commercially available raw materials such as 3-methylpyridine and 5-ethyl-2-methylpyridine, especially focusing on those methods with potential industrial applications.
This paper reports the results of studies concerning an alternative method of obtaining dicarboxylic acids, which consist of the oxidation of cyclic ketones with oxygen or air. The raw materials used were cyclopentanone, cycloheptanone, cyclooctanone, cyclododecanone, 1-tetralon, 2-methylhexanone, 3-methylcyclohexanone and 4-methylcyclohexanone. Oxidation reactions were conducted at 70-100 o C, under pressure of 0.1 or 0.4 MPa, for 6 h, utilizing the salts of transition metals as catalyst and acetic acid as solvent. For example, when cyclopentanone was oxidized in the presence of Mn(II) salt, a conversion above 98% and selectivity to glutaric acid up to 68% were obtained. Among synthesized dicarboxylic acids, 1,12-dodecanoic acid was obtained with the highest selectivity of 76%.
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 O2 or air under mild conditions in the presence of N-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. This was due to the greater oxidizability of CH=O compared to CH. The peroxyl radicals formed by CH=O oxidation initiated the oxidation of the less reactive CH. Additionally, CH=O increased the polarity of the reaction mixture, promoting the solubility of NHPI. The influence of type and amount of catalyst, cyclohexane to cyclohexanone ratio, temperature, time, type of oxidizing agent on the composition of CH/CH=O oxidation products have been reported.
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