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The present paper is dedicated to the development of a method for the nitrobenzene production using solid acid catalysts, as an alternative to industrial nitration, based on a mixture of concentrated acids. 0000067855 00000 n
© 2016 Tomsk Polytechnic University. Most nitrobenzene produced is reduced to aniline; smaller amounts are converted to azobenzene, hydrazobenzene (the intermediate for benzidine), and phenylhydroxylamine. Carried below 50 o C to avoid further substitution of nitro groups. 0000007968 00000 n
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Nitration happens when one (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO 2. 167 32
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Conditions: concentrated nitric acid and concentrated sulfuric acid. 0000013129 00000 n
Benzene is treated with a mixture of concentrated nitric acid and concentrated sulphuric acid at a temperature not exceeding 50°C. A method for regeneration of the catalytic activity without unloading the catalyst was proposed. nitrobenzene: first to nitrosobenzene, next to phenylhy-droxylamine, and finally to aniline. 0000005289 00000 n
This reaction is known as nitration of benzene. 0
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Nitrobenzene undergoes nitration, halogenation, and sulfonation much more slowly than does benzene. 0000007359 00000 n
The mixture is held at this temperature for about half an hour. 0000103614 00000 n
We have already noted that benzene does not react with chlorine or bromine in the absence of a catalyst and heat. 0000000016 00000 n
x�b```b``�e`e`bd@ A6v�-�ܝ.���oY��=G3�iҟ���B'oom ``��`kr%5F�KD1� 2`�S0���:����S�iz%���,��_���x�s�J@`���B��Voq+��C��b�Ѭ�EV�mYt. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Nitration happens when one (or more) of the hydrogen atoms on the benzene ring is replaced by a nitro group, NO 2. Benzene is nitrated by replacing one of the hydrogen atoms on the benzene ring by a nitro group, NO 2. It may be reduced to a variety of compounds, depending on the reaction conditions. Benzene reacts with concentrated nitric acid at 323-333k in the presence of concentrated sulphuric acid to form nitrobenzene. Several of the most promising catalysts (MoO3/SiO2, WO3/ZrO2 and Nafion/support composite) for the process were tested in identical conditions. 0000011482 00000 n
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Benzene conversion was determined based on a predetermined calibrating curve (XB = f (d of)). 0000006102 00000 n
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We use cookies to help provide and enhance our service and tailor content and ads. 0000002514 00000 n
Common benzene reactions are Nitration of Benzene. 0000017676 00000 n
Recommendations for the selection of effective catalytic systems (high content of Brønsted acid sites with Ho < −4, high specific surface and resistance to HNO3) were developed and the best conditions for process reactions (temperature 200 °C, aqueous solution of nitric acid with concentration of 30 wt%, “nitric acid:benzene” ratio = 0.76) were found. The nitration of benzene. The influence of key parameters of the nitration process (temperature, reagent flow rate, nitrating agent concentration etc.) The nitration of benzene. 0000014029 00000 n
In strong sunlight or with radical initiators benzene adds these halogens to give hexahalocyclohexanes. on the conversion of the initial substrate, the degree of decomposition of nitric acid and the quantity of resulting oxygenates was studied. Nitrobenzene to phenylamine / reduction of nitro benzene. Yellow oily nitrobenzene is formed. trailer
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Benzene is more susceptible to radical addition reactions than to electrophilic addition. 167 0 obj <>
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Yellow oily nitrobenzene is formed. xref
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In the calibrating experiments a series of pure nitrobenzene (99.9%) and benzene (99.9%) solutions was used. The mixture is held at this temperature for about half an hour. If the concentrations of nitrosobenzene and phenylhydroxylamine are allowed to increase, the 0000072576 00000 n
As an example, MoO3/SiO2 sample was tested in a dual-mode nitration/regeneration process, which allowed us to increase the flow rates of reagents and obtain catalyst efficiency of up to STY = 4.09 g/(gcat ⋅ h). Reduction of both the nitro group and the … 0000010548 00000 n
Conditions: Tin and concentrated hydrochloric acid and excess sodium hydroxide and reflux. Benzene to nitrobenzene. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. Benzene is treated with a mixture of concentrated nitric acid and concentrated sulfuric acid at a temperature not exceeding 50°C. By continuing you agree to the use of cookies. Production and hosting by Elsevier B.V. https://doi.org/10.1016/j.reffit.2016.07.004. Peer review under responsibility of Tomsk Polytechnic University. In search of efficient catalysts and appropriate reaction conditions for gas phase nitration of benzene. The mixture is held at this temperature for about half an hour. Benzene to nitrobenzene / nitration of benzene. The benzene is treated with a mixture of concentrated nitric acid and concentrated sulphuric acid at a temperature not exceeding 50°C. startxref
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This path, we will see, is favored under conditions in which the concentrations of nitrobenzene are low, < 0.15 %. 0000007074 00000 n
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Yellow oily nitrobenzene is formed. 0000002365 00000 n
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The method embraces selecting and weighing (±0.001 g) of an OP aliquot (±0.01 mL) in normal conditions (20 ± 0.1 °С, 1 atm).