scholarly journals HYDROGEN ROLE IN SELECTIVITY OF SUBSTITUTED NITRO-AZOBENENES HYDROGENI-ZATION ON SKELETAL NICKEL IN 2-PROPANOL AQUEOUS SOLUTIONS

2020 ◽  
Vol 63 (6) ◽  
pp. 65-71
Author(s):  
Olga V. Lefedova ◽  
Hoang Anh ◽  
Dmitriy V. Filippov
Keyword(s):  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Nitro Group ◽  
Intramolecular Rearrangement ◽  
Transformation Rate ◽  
Group Transformation ◽  
Skeletal Nickel ◽  
Starting Compound ◽  
Azo Group ◽  
The Individual

Elucidation of the substituted nitrobenzenes transformations sequence, in particular, containing several reactive groups and the development of approaches to the control of the selectivity of processes involving them is of interest from both theoretical and practical points of view. The article is devoted to the analysis of the hydrogenation kinetics of 2-nitro-2'-hydroxy-5'-methylazobenzene, 4-nitro-2'-hydroxy-5'-methyl-isobenzene, 4-nitroaniline, 4-amino-2'-hydroxy-5'-methylazobenzene on skeletal nickel in 2-propanol aqueous solutions of different composition, including with the addition of acetic acid or sodium hydroxide with various initial amounts of organic compound. The rise in the 4-nitro-2'-hydroxy-5'-methylazobenzene initial amount leads to increase in the nitro group transformation rate in the starting compound and to decrease in the azo-group transformation rate. The effect of sodium hydroxide additives in the 2-propanol aqueous solution on the nitro- and azo-groups conversion rate into 4-nitro-2'-hydroxy-5'-methyl-isobenzene is analogous to the change in the individual compounds hydrogenation rates (4-nitroaniline and 4-amino-2'-hydroxy-5'-methylazobenzene). Obtained results do not contradict the parallel-sequential scheme concept for the 4-nitro-2'-hydroxy-5'-methylazobenzene transformations. One of the directions is associated with the azo-group transformation into 4-nitro-2'-hydroxy-5'-methylazobenzene and 4-nitroaniline and 2-amino-4-methylphenol formation, and the second with the 4-nitro-2'-hydroxy-5'-methyl-isobenzene conversion through 4-amino-2'-hydroxy-5'-methyl-isobenzene by the nitro-group reducing. At the reaction end, all intermediate compounds are reduced to 2-amino-4-methylphenol and 1,4-phenylenediamine. When 2-nitro-2'-hydroxy-5'-methylazobenzene is hydrogenated, one of the directions leads to the 2-nitro-2'-hydroxy-5'-methylhydrazobenzene formation, and the second to the product containing the triazole cycle - N-oxide 2-2'-hydroxy-5'-methylphenylbenzotriazole. At the reaction end, these compounds are reduced to 2-2'-hydroxy-5'-methylphenylbenzotriazole and 2-amino-4-methylphenol and 1,2-phenylenediamine, respectively. In the solution at the sodium hydroxide presence, 2-nitro-2'-hydroxy-5'-methylhydrazobenzene transforms into the N-oxide 2-2'-hydroxy-5'-methylphenylbenzotriazole as a result of intramolecular rearrangement.

scholarly journals INFLUENCE OF SODIUM HYDROXIDE ADDITIVES ON HYDROGENIZATION KINETICS OF 4-NITRO-2'-HYDROXY-5'-METYLAZOBENZENE ON SKELETAL NICKEL IN AQUEOUS SOLUTION OF 2-PROPANOL

2018 ◽  
Vol 61 (8) ◽  
pp. 66
Author(s):  
Anh Hoang ◽  
Vera A. Kalashnikova ◽  
Olga V. Lefedova ◽  
Dmitriy V. Filippov
Keyword(s):  
Aqueous Solution ◽  
Sodium Hydroxide ◽  
Nitro Group ◽  
Skeletal Nickel ◽  
Starting Compound ◽  
Azo Group ◽  
Reactive Groups ◽  
Kinetics Of ◽  
Neutral Solvent

The elucidation of the sequence of transformations in compounds containing several reactive groups and the development of approaches to controlling the selectivity of the processes with their participation is of interest both from the theoretical and practical points of view. The article is devoted to the analysis of the kinetics of hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene in aqueous solution of 2-propanol with addition of sodium hydroxide on skeletal nickel at different initial amounts of the starting compound. An increase in the initial amount of 4-nitro-2'-hydroxy-5'-methylazobenzene leads to an increase in the rate of conversion of the nitro group in the starting compound and to a decrease in the rate of conversion of the azo-group. The effect of the introduced sodium hydroxide in the neutral solvent 2-propanol-water on the rate of conversion of the nitro and azo-groups to 4-nitro-2'-hydroxy-5'-methylazobenzene is consistent with the nature of the rate changes for the hydrogenation of individual compounds containing nitro and azo-groups, in the quality of which 4-nitroaniline and 4-amino-2'-hydroxy-5'-methylazobenzene were chosen. The results obtained do not contradict the notion of a parallel-sequential scheme of 4-nitro-2'-hydroxy-5'-methylazobenzene transformations. One of the directions involves the conversion of 4-nitro-2'-hydroxy-5'-methylazobenzene due to the hydrogenation of the azo-group to 4-nitroaniline and PC, and the second one is the conversion of 4-nitro-2'-hydroxy-5'-methylazobenzene through 4-amino-2'-hydroxy-5'-methylazobenzene due to the reduction of the nitro group. By the end of the reaction, all the intermediate compounds are restored to PC and 1,4-phenylenediamine. When sodium hydroxide is introduced into the neutral solvent 2-propanol-water, the effect of the direction providing the formation of 4-amino-2'-hydroxy-5'-methylazobenzene to the overall reaction rate increases. It was experimentally established that the amount of 4-amino-2'-hydroxy-5'-methylazobenzene during the hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene in the presence of sodium hydroxide increases by 15%, on the contrary, the amount of 4-nitroaniline decreases by 4 % in comparison with the neutral solvent.

scholarly journals INFLUENCE OF ADDITIVES OF ACID ON STAGE OF TRANSFORMATIONS OF 4-NITRO-2'-HYDROXY-5'-METHYLASOBENZENE ON SKELETONIC NICKEL IN WATER SOLUTION OF 2-PROPANOL

2020 ◽  
Vol 63 (7) ◽  
pp. 41-47
Author(s):  
Hoang Anh ◽  
Olga V. Lefedova ◽  
Alexandra.V. Belova
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Maximum Yield ◽  
Bulk Solution ◽  
Skeletal Nickel ◽  
Acid Addition ◽  
Starting Compound ◽  
Conversion Rates ◽  
Azo Group ◽  
Neutral Aqueous Solution

The article is devoted to the analysis of the reaction kinetics of hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene in an aqueous solution of 2-propanol with acetic acid addition on skeletal nickel at different initial quantity of the starting compound. Clarification of the sequence of transformations of compounds containing several reactive groups, and the development of approaches to controlling the selectivity of processes with their participation is a practically significant task. According to the data obtained, at both low and high initial concentrations the hydrogenation of 4-nitro-2'-hydroxy-5'-methylazobenzene on skeletal nickel in a 2-propanol aqueous solution-0.01 M CH3COOH solvent proceeds in two parallel directions. The largest contribution in the first phase of the reaction is made by the azo group conversion of the starting compound, in contrast to the reaction in an aqueous solution of 2-propanol without acid addition. An increase in the initial quantity of the hydrogenated compound above its solubility limit leads to an increase in the rate of conversion of the azo group in 4-nitro- and 2-amino-2'-hydroxy-5'-methylazobenzene. Consequently, optimum quantity of 4-nitroaniline and 2-amino-2'-hydroxy-5'-methylazobenzene in the bulk solution during hydrogenation of the specified quantity of 4-nitro-2'-hydroxy-5'-methylazobenzene practically didn’t change, in contradiction to the hydrogenation on skeletal nickel in a neutral aqueous solution of 2-propanol. In a neutral aqueous solution of 2-propanol, when passing to high concentrations of the hydrogenated compound, the maximum yield of 4-nitroaniline increases twice as long the better, while as 4-amino-2'-hydroxy-5'-methylazobenzene, is reduced conversely. The results obtained do not contradict the concept of a parallel-sequential scheme for the conversion of 4-nitro-2'-hydroxy-5'-methylazobenzene. One of the directions involves the conversion of 4-nitro-2'-hydroxy-5'-methylazobenzene through 4-nitroaniline and 2-amino-4-methylphenol due to the hydrogenation of the azo group, and the second is the conversion of 4-nitro-2'-hydroxy-5'- methylazobenzene via 4-amino-2'-hydroxy-5'-methylazobenzene by reduction of the nitro group. At the end of the reaction, all the intermediate compounds are reduced to 2-amino-4-methylphenol and 1,4-phenylenediamine. When acetic acid is introduced into the composition of the neutral solvent 2-propanol-water, the contribution of the direction that ensures the formation of 4-nitroaniline and 2-amino-4-methylphenol to the overall reaction rate increases. An increase in the initial amount of 4-nitro-2′-hydroxy-5′-methyl-azobenzene leads to an increase in the rate of conversion of the azo group in the starting compound and to a decrease in the rate of conversion of 4-amino-2′-hydroxy-5′-methylazobenzene. The effect of the acid on the change in the conversion rates of nitro and azo groups to 4-nitro-2′-hydroxy-5′-methylazobenzene does not contradict the previously obtained results for the hydrogenation of its analogue, 2-nitro-2′-hydroxy-5-methylazobenzene, as well as individual compounds containing a nitro and azo group.

The preparation of sodium 4-Amino-3-nitro-benzenesulfonate and some related compounds

1982 ◽  
Vol 35 (8) ◽  
pp. 1727 ◽  
Author(s):  
J Rosevear ◽  
JFK Wilshire
Keyword(s):  
Sodium Hydroxide ◽  
Nitro Group ◽  
Sodium Salt ◽  
Sulfonic Acid ◽  
Sodium Hydroxide Solution ◽  
Hydroxide Solution ◽  
Dilute Sodium Hydroxide ◽  
Related Compounds

The sodium salt of 4-amino-3-nitrobenzenesulfonic acid (O-nitroaniline-p-sulfonic acid) has been prepared by the action of dilute sodium hydroxide solution on ethyl [(4-chlorosulfonyl-2-nitro)- phenyllcarbamate. Central to this synthesis is the finding that the N-ethoxycarbonyl group, when located ortho to a nitro group (but not to a bromo group), is readily removed by dilute sodium hydroxide solution.

scholarly journals Inhomogeneities in PNIPAM Aqueous Solutions: The Inside View by Spin Probe EPR Spectroscopy

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3829
Author(s):  
Ekaterina M. Zubanova ◽  
Sergei V. Kostjuk ◽  
Peter S. Timashev ◽  
Yury A. Rochev ◽  
Alexander I. Kokorin ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Coming Out ◽  
Epr Spectroscopy ◽  
Spin Probe ◽  
Guest Molecule ◽  
Continuous Wave ◽  
Paramagnetic Resonance ◽  
Molten Globules ◽  
The Individual ◽  
Tempo Radical

Coil to globule transition in poly(N-isopropylacrylamide) aqueous solutions was studied using spin probe continuous-wave electronic paramagnetic resonance (CW EPR) spectroscopy with an amphiphilic TEMPO radical as a guest molecule. Using Cu(II) ions as the “quencher” for fast-moving radicals in the liquid phase allowed obtaining the individual spectra of TEMPO radicals in polymer globule and observing inhomogeneities in solutions before globule collapsing. EPR spectra simulations confirm the formation of molten globules at the first step with further collapsing and water molecules coming out of the globule, making it denser.

The alkali-induced elimination of phosphate from β-casein

1972 ◽  
Vol 39 (2) ◽  
pp. 189-194 ◽  
Author(s):  
W. Manson ◽  
T. Carolan
Keyword(s):  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Inorganic Phosphate ◽  
Type A ◽  
Dilute Aqueous Solutions

SummaryThe dephosphorylation of β-casein, type A1, by dilute aqueous solutions of sodium hydroxide has been studied. It has been found that the mechanism whereby inorganic phosphate is liberated by the action of alkali is one of β-elimination from O-phosphoserine residues which are themselves converted initially to dehydroalanyl residues.

scholarly journals Solar photodegradation of carbamazepine from aqueous solutions using a compound parabolic concentrator equipped with a sun tracking system

2019 ◽  
Vol 17 (1) ◽  
pp. 477-484 ◽  
Author(s):  
Ahmadreza Yazdanbakhsh ◽  
Reza Nemati ◽  
Mohamadreza Massoudinejad ◽  
Mohamadjavad Jafari ◽  
Masoomeh Dashtdar
Keyword(s):  
Organic Compound ◽  
Aqueous Solutions ◽  
Tracking System ◽  
Transformation Rate ◽  
Solution Ph ◽  
Photo Degradation ◽  
Compound Parabolic Concentrator ◽  
Reactor Temperature ◽  
By Products ◽  
Complete Mineralization

AbstractThe primary purpose of this study was to investigate the efficiency of a Compound Parabolic Concentrator (CPC) equipped with a sun tracking system in the photolysis of carbamazepine as a refractory organic compound. The natural sunlight experiments were accomplished during the period May–July 2017 in Tehran, Iran. The intermediate by-products of the process of solar photodegradation of carbamazepine (CBZ) were characterized using LC–MS. The results showed that increasing the reactor temperature did not significantly change CBZ degradation efficiency. However, the solution pH played a comparatively important role in CBZ solar photo degradation: removal efficiency increased considerably with pH from about 49% at pH 7 to almost 61% at pH 9. According to our findings, using a CPC reactor equipped with a sun tracker system promotes the solar photo-transformation rate of CBZ by 2-3 fold. In addition, LC/MS analysis showed that eight main intermediates were formed in the treated solution after solar photodegradation of CBZ. Therefore, complete mineralization of CBZ was not accomplished.

Electrolytic Interaction of Nylon with Aqueous Solutions of Sodium Hydroxide

1952 ◽  
Vol 56 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Frederick T. Wall ◽  
Thomas J. Swoboda
Keyword(s):  
Aqueous Solutions ◽  
Sodium Hydroxide

Pulse Radiolysis and Simulation Computation Studies on Acridine Orange in Aqueous Solutions

1982 ◽  
Vol 37 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Sonja Solar ◽  
Wolfgang Solar ◽  
Nikola Getoff
Keyword(s):  
Aqueous Solutions ◽  
Acridine Orange ◽  
Pulse Radiolysis ◽  
Simulation Method ◽  
Energy Utilization ◽  
Simultaneous Formation ◽  
Chromophore Group ◽  
Extinction Coefficients ◽  
Solar Energy Utilization ◽  
The Individual

Abstract A combined pulse radiolysis-computer simulation method was applied for the elucidation of the complicated multiple H-attack on acridine orange in aqueous solutions at pH = 1 to 3. The simultaneous formation of three intermediates was established: semiquinone (H-addition on the N-atom of the chromophore group), R--species (reaction on the meso-C-atom) and H-adducts on the aromatic ring carbon. Their superimposed spectra were resolved, the individual extinction coefficients and the rate constants for their formation and decay were determined. The results are of importance in particular for understanding the decomposition of acridine orange applied as sensitizer in various devices for solar energy utilization.

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