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CATALYTIC REDUCTION OF AROMATIC MONO NITRO
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| CATALYTIC REDUCTION OF AROMATIC MONO NITRO
COMPOUNDS OF DIFFERENT STRUCTURE IN LIQUID PHASE Kairdenov Sh.A., Zharkyn M.K. Karimbaev S.E. Supervisor Prof. L.R. Sassykova Al-Farabi Kazakh National University larissa.rav@mail.ru Aromatic mono-, di- and polyamines are widely applied in the production of synthetic dyes, photochemicals, fuel stabilizers and additives lubricating oils, chemical plant protection products, synthetic fibers, sorbents, medicines. The total production of amines in the world is more than 3-4 million tons/year. Obviously that the problem of improving the technology of obtaining these compounds can be considered actual. The most important way of amines producing is catalytic reduction of nitro compounds by hydrogen on catalysts. In this work catalytic reduction of mono nitro compounds, nitrobenzene (NB), ortho, para-, ortho-nitrophenols (o-NP, p-NP, o-NP), ortho, meta-, para-nitroanilines (o-NA, m-NA, p-NA) and p-nitrodiethyl aniline (p-NDA) has been investigated. The enlarged laboratory tests on the synthesis of p-phenylenediamine, o-aminophenol, and p-aminophenol under optimal process conditions on the most effective and selective catalysts have been performed. For the charge, 50 g of the substance and 200 ml of solvent were taken. The distilled water, C 1 -C 5 alcohols of the grade “CP” were used as solvents. The reaction was carried out at the installation on the basis of “catalytic duck” and a high-pressure kinetic unit (HPKU), consisting of an advanced Vishnevsky autoclave with intensive mixing and a measuring part. The process was performed with electrolytic hydrogen from a balloon (99.8%); for gas-liquid chromatography (GLC) helium (99.992%) was used. For the research the catalysts based on Pt and Pd and deposited on γ-Al 2 O 3 and coal (C), prepared by applying appropriate compounds to the carrier by impregnation have been applied. It was found that the studied nitro compounds on decreasing the initial rate of hydrogenation form a series: NB> p-NA > m-NA> p-NDA (p-NP) >> o-NP. The high catalytic activity of Pd-based catalysts compared to the Ni catalyst allowed the reaction to be carried out under milder conditions. The results of enlarged tests show that using relatively small amounts of catalysts (0.48-0.6 g of catalyst by hydrogenating 50 g of an aromatic nitro compound) it is possible to obtain high amine yields of 90-98.7%. жүктеу/скачать 0,93 Mb. Достарыңызбен бөлісу:
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