Nitrosylsulfuric Acid Research Articles

Process Intensification: Continuous Synthesis of Nitrosyl Sulfuric Acid in a Rotating Packed Bed Reactor

Process Intensification: Continuous Synthesis of Nitrosyl Sulfuric Acid in a Rotating Packed Bed Reactor

Synthesis, characterization, spectroscopic properties and computational studies of some new azo dyes derived from 5-chloro-8-hydroxy quinoline

Purpose The purpose of this study, 3-aminopyridine, 8-aminoquinoline and some new synthesized 2-aminobenzothiazoles were diazotized with nitrosyl sulfuric acid and subsequently coupled with 5-chloro-8-hydroxy quinoline to synthesize the corresponding heteroarylazo dyes 6–13. Design/methodology/approach The structures of dyes were characterized by mass, Fourier transform infra red, 1H proton nuclear magnetic resonance and ultra violet-visible spectroscopic techniques. Absorption spectra of the dyes were measured in acetic acid, ethanol, chloroform, acetonitrile, dimethyl formamide and dimethyl sulfoxide and correlated with the nature of the solvents and substituents. The effects of varying pH on the absorption wavelengths of the azo dyes were also studied. In addition, the acidity constants (pKa) of the dyes were determined using the spectrophotometric method in an ethanol-water mixture (80:20, v/v) at 20–23°C. Besides, density functional theory (DFT) calculations were carried out to compare the energies of proposed azo and hydrazone tautomers of the dyes. Findings The results showed that the withdrawing chloro groups on the diazo moiety have significant influence (red shift) on the electron absorption spectra of these dyes. In addition, introducing electron withdrawing chloro groups into the benzothiazoles moiety increased the acidic character of dyes. Originality/value The synthesized 7-hetroarylazo-5-chloro-8-hydroxy quinoline dyes are new members in the 8-hydroxyquinoline azo dyes family, where very few details regarding the synthesis of such dyes are reported before in the literature. They are unique in terms of synthesis, spectral properties and DFT calculations.

Trapping nitrous gases during nitric acid leaching of sulfide concentrates

Gas-air mixtures that form in nitric acid leaching of sulfide raw materials possess the following peculiarities making a negative impact on trapping of nitrogen oxides: elevated temperature, different oxidation level of nitrogen oxides, slow oxidation of NO in region of low concentrations, and instability of the resulting gas-air mixture flow. Therefore, well-known methods of trapping nitrous gases shall be adapted to specific sulfide raw material. We propose a process flow diagram for trapping nitrous gases formed during nitric acid leaching of sulfide concentrates at atmospheric pressure on the example of Zhezkazgan concentrate. The paper addresses theoretical aspects of the use of water-ore pulp, concentrated sulfuric acid, process water and alkaline agents for trapping nitrous gases, and typical reactions of interaction of the proposed absorbents with nitrogen oxides. The choice of water-ore pulp as an absorber was made because of similarity between the mechanism of absorption of nitrogen oxides for neutral and alkali ore suspensions and the one for alkali solutions: nitrogen dioxide and nitrous anhydride are absorbed with formation of a solution of nitrates and nitrites. Due to availability in a liquid phase of ferrous iron along with NO2 and N2O3, acidic suspensions are also capable to absorb nitric oxide, to some extent, with formation of Fe(NO)SО4 complex. Process water absorbs only nitrogen dioxide, with formation of nitric and nitrous acids. Nitrous acid is an unstable compound in acidic environments and decomposes with formation of water and nitrogen oxide. At the stages of trapping nitrogen oxides with water-ore pulp and process water (circulating solution), it is recommended conditioning of gas-air mixtures by choosing the volume of additionally introduced air, in an amount to provide the highest rate of nitrogen oxide oxidation. At the stages of sulfuric acid and alkaline trapping of nitrogen oxides, it is recommended conditioning of gas-air mixtures by selecting the volume of additionally introduced air and the oxidation time of nitrogen oxide that provide an equimolecular mixture of NO and NO2. A distinctive feature of the use of water-ore pulp, concentrated sulfuric acid, process water and alkaline agents for trapping nitrous gases is possibility to use the products of absorption at the stage of sulfide concentrate leaching. The extended tests of trapping nitrous gases have been conducted. The plant capacity by the gas-air mixture ranged 17–21 m3/h, and by leached concentrate — 12–15 kg/h. In this case, the degree of capturing nitrous gases reached 96.8%. Return of the products of absorption of nitrous gases in the form of condensate, water-ore pulp, nitrosyl sulfuric acid, nitric acid solution, nitritenitrate lye allows to reduce the nitric acid consumption by 7–10 times relative the values obtained without using the trapping system. In this case, the degree of copper extraction into the leaching solution was 97.7%. The extraction degree of silver, rhenium, zinc was respectively 98.0%, 99.0%; 98.5%.

Синтез 5-гидрокси-10-R-бензо[а]феназин-12-оксидов циклизацией 2-ариламино-1,4-нафтохинон-1-оксимов под действием нитрующей смеси

The synthesis of рolycyclic quinoid compounds, which exhibit a wide range of biological activity is one of the most promising and actively developing areas of the fine organic synthesis. Heterocyclic compounds including those that can be donors of nitrogen oxide NO occupy a special place among biologically active structures. These substances include a number of N-oxides, e.g., 1,2-diazet-1,2-dioxides, furoxanes and their benzo analogs, and N,N′-pyrazole dioxides. The reason for the high biological activity of N-oxides of nitrogenous heterocycles, which cannot easily generate nitrogen oxide NO may be their oxidative properties. Thus, N-oxides of nitrogenous heterocycles are of interest due to their high biological activity. We have developed an approach to the synthesis of 5-hydroxy-10-R-benzo[a]phenazine-12-oxides that contain the N-oxide fragment, which makes these compounds promising for studying their biological activity. We have demonstrated that the treatment of 2-arylamino-1,4-naphthoquinones with hydroxylamine in ethanol at 50-60 °С leads to selective oximation at position 1 and the formation of 2-arylamino-1,4-naphthoquinone-1-oximes. It has been shown that the interaction of 2-arylamino-1,4-naphthoquinone-1-oximes with the nitrating mixture in acetic acid results in the formation of 5-hydroxy-10-R-benzo[a]phenazine-12-oxides. Our work is a continuation of the study on the interactions of 2-arylamino-1,4-naphthoquinones and 4-arylamino-1,2-naphthoquinones with nitrosylsulfuric acid in acetic acid and the interaction of 2-alkyl(benzyl)amino-1,4-naphthoquinones with nitrosylsulfuric acid or nitrating mixture in acetic acid. The former reactions lead to the formation of 3-R-benzo[b]phenazine-6,11-dione-5-oxides and 9-R-benzo[a]phenazine-5,6-dion-7-oxides, respectively. The latter reaction leads to the formation of 2-alkyl(aryl)naphtho[2,1-d][1,3]oxazole-4,5-dione-4-oximes and 2-alkyl(aryl)-1-hydroxy-1H-naphtho[2,3-d]imidazole-4,9-dione as main products.

Nitrosylsulfuric acid in the synthesis of 5-chloroisoxazoles from 1,1-dichlorocyclopropanes

Nitrosylsulfuric acid is shown to be a usable reagent for the synthesis of 5-chloroisoxazoles from readily available 1,1-di-chlorocyclopropanes via nitrosation–heterocyclization reaction. A cytotoxicity of some of the prepared 5-chloroisoxazoles towards MCF7, A549, HEK293T and VA13 cell lines was evaluated.

Nitrosylsulfuric acid as a tandem reagent in the synthesis of 3,5-diarylisoxazoles from 1,2-diarylcyclopropanes

It was demonstrated that nitrosylsulfuric acid can be successfully used as a tandem nitrosating and oxidizing agent in the synthesis of 3,5-diarylisoxazoles from 1,2-diarylcyclopropanes. The reaction proceeds highly regioselectively in the case of symmetric diarylcyclopropanes. The mixtures of regioisomeric 3,5-diarylisoxazoles were obtained from non-symmetric 1,2-diarylcyclopropanes.

On the Reaction of 2-Benzylamino-1,4-naphthoquinones with Nitrosylsulfuric Acid

The reaction of 2-benzylamino-1,4-naphthoquinone with nitrosylsulfuric acid in acetic acid results in preferential formation of 2,1- and 2,3-heterocyclization products: (E)-4-(hydroxyimino)-2-phenylnaphtho [2,1-d]oxazol-5(4H)-one and 2-phenyl-1-hydroxy-1H-naphtho[2,3-d]imidazole-4,9-dione. In addition, 2-phenylnaphtho[2,1-d]oxazol-4,5-dione and N-(3-nitro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)benzamide are also formed. The reaction of 2-benzylamino-3-chloro-1,4-naphthoquinone with nitrosylsulfuric acid in acetic acid gives 3-diazonapthalene-1,2,4(3H)-trione and benzaldehyde.

Nitrosylsulfuric acid as an oxidant in the synthesis of 3,5-diarylisoxazoles

By six examples, it was demonstrated that nitrosylsulfuric acid can be successfully used for oxidation of 3,5-diaryl-4,5-dihydroisoxazoles to the corresponding 3,5-diarylisoxazoles. If the starting isoxazolines contain the aromatic substituents activated towards electrophilic substitution, nitration of both newly formed isoxazole and substituted benzene rings occurred.

Anhydrous Dinitrogen Trioxide Solutions for Brønsted Acid Free Nitrous Acid Chemistry

Dinitrogen trioxide, N2O3, is readily prepared and stabilized in high concentrations in dry organic solvents at normal working temperatures. These conditions allow for facile acid and water free nitrosation and nitration reactions for which three examples are given here: the preparation of benzenediazonium nitrite, [PhN2][NO2]; nitrosyl chloride, NOCl, and nitrosylsulfuric acid, (ONOSO3H).

Oxysulfonation of coke coal by nitrosylsulfuric acid

The interaction of coke coal with nitrosylsulfuric acid NOHSO4 in acetonitrile at 20–25°C, times to 24 h, and the NOHSO4/coal ratio R ≤ 50 mmol/g was studied. The process leads to the formation of oxysulfonated coal accompanied by an increase in the weight (to 46%), a decrease (by a factor of 3.8–7.3) in the concentration of radicals, and the formation of the following O-, S-, and N-containing groups in the coal structure: carboxyl, phenol, sulfo groups (≤1.9 mmol/g), and nitroso groups (≤0.9 mmol/g). Changes in the characteristics of oxysulfonated coal under varying R and upon hydrolysis were established by IR and EPR spectroscopy and elemental analysis. The results were interpreted within the framework of a mechanism that included the formation of coal radical cations as a result of electron transfer from coal to the nitronium cation, the intercalation of the bisulfate anion into the coal structure, and the nitrosation and sulfonation of coal arenes. Side oxidation reactions occurred simultaneously with the formation of carboxyl, phenol, and quinoid groups.

Synthesis and investigation of antimicrobial activity and spectrophotometric and dyeing properties of some novel azo disperse dyes based on naphthalimides.

A series of novel disperse dyes containing azo group were synthesized through a diazotization and coupling process. The 4-amino-N-2-aminomethylpyridine-1,8-naphthalimide was diazotized by nitrosylsulphuric acid and coupled with various aromatic amines such as N,N-diethylaniline, N,N-dihydroxyethylaniline, 8-hydroxyquinoline, and 2-methylindole. Chemical structures of the synthesized dyes were characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), proton nuclear magnetic resonance ((1) H NMR), carbon nuclear magnetic resonance ((13) C NMR), elemental analysis, and ultraviolet-visible (UV-visible) spectroscopy. The spectrophotometric data of all dyes were evaluated in various solvents with different polarity. Eventually, the dyes were applied on polyamide fabrics in order to investigate their dyeing properties. The fastness properties of the dyed fabrics such as wash, light, and rubbing fastness degrees were measured by standard methods. Moreover, the color gamut of the synthesized dyes was measured on polyamide fabrics. Results indicated that some of the synthesized dyes were able to dye polyamide fabrics with deep shades. They had very good wash and rubbing fastness degrees and moderate-to-good light fastness on polyamide fabrics. The antibacterial and antifungal activities of the synthesized dyes were evaluated in soluble state and on the dyed fabrics. The results indicated that dye 2 containing N,N-dihydroxyethylaniline as coupler had the highest activity against all the bacteria and fungi used.

Synthesis and structural characterization of bisazocalix[4]arene with melamine: Metal ion extraction studies

In this study, the synthesis and characterization of novel bisazocalix[4]arene [2-amino-4,6-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)-1,3,5-triazine] (5), symmetrically derived from the diazo coupling of 2,4,6-triamino-1,3,5-triazine (melamine), were carried out. This compound was prepared by reacting 25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene (3) and melamine (4) in nitrosyl sulfuric acid and DMF. Purified product was characterized by elemental analyses, FT-IR, 1H-NMR, MS and thermogravimetric analysis (TGA) techniques. Complexation properties of synthesized compound were studied by the liquid–liquid extraction of selected metal cations (Na+, K+, Sr2+, Ag+, Hg+, Hg2+, Co2+, Ni2+, Cu2+, Cd2+, Pb2+, Zn2+, Cr3+, Al3+). It has been observed that bisazocalix[4]arene shows high affinity to Hg+ and Hg2+ ions, whereas almost less affinity to other metals. This sensor therefore present a very significant advantage in that it allows for determination of mercury ion in environmental and industrial wastewater.

Transformation of 2-alkylamino-1,4-naphthoquinones into 2-alkylnaphtho[2,1-d][1,3]oxazole-4,5-dione 4-oximes by the action of nitrosylsulfuric acid

2-Alkylnaphtho[2,1-d][1,3]oxazole-4,5-dione 4-oximes were synthesized by reaction of 2-alkylamino-1,4-naphthoquinones with nitrosylsulfuric acid in acetic acid.

ChemInform Abstract: The Synthesis of Benzo[a]phenazine‐5,6‐dione 7‐Oxides.

AbstractThe title compounds (II), a new type of tetracyclic azine heterocycles incorporating quinoid structures, are conveniently obtained by treatment of naphthoquinones (I) with nitrosylsulfuric acid.

Cyclohexane nitrosation to ϵ-caprolactam with high selectivity over HY supported transition metals and phosphotungstic acid catalysts

Transition metals and phosphotungstic acid were supported on HY by impregnation method. In addition, these prepared catalysts were used in the synthesis of ϵ-caprolactam from one-step nitrosation of cyclohexane in different reaction medium of oleum and concentrated sulphuric acid. Among these catalysts, the PW/HY gives better result of cyclohexane conversion of 9·9% and selectivity to ϵ-caprolactam of 75·9%. X-ray diffraction, Fourier transform infrared (FTIR), NH3–temperature programmed desorption, pyridine FTIR, SEM, Brunauer–Emmett–Teller and N2 adsorption–desorption were used to characterise the HY and PW/HY. The characterisation results as well as the catalytic performance indicate that the increment of the Brønsted acid sites has positive effect on the cyclohexane nitrosation to ϵ-caprolactam. The catalysts play an important role in promoting nitrosyl sulphuric acid to form nitroso radical and further to obtain ϵ-caprolactam. In addition, a possible mechanism for liquid phase nitrosation of cyclohexane in different reaction medium was proposed.

Synthesis, characterization and theoretical study of new hetarylazopyrazolone dyes and investigation of their absorption spectra

A series of hetarylazopyrazolone dyes were synthesized by coupling 1-(2-benzothiazolyl)-3-methylpyrazol-5-one with six heterocylic amines prepared in nitrosyl sulphuric acid. The dyes were characterized by spectral methods and elemental analysis. The solvatochromic properties of the dyes were investigated in various solvents. Additionally, acid–base, concentration, temperature and substituent effects on the visible absorbtion spectra were also examined.The ground-state geometry of the synthesized compounds were studied by using density functional theory (DFT) calculations at the B3LYP/6-31+G(d) level of theory. The absorption spectra of the dyes are obtained by using time-dependent density functional theory (TD-DFT) method associated with the integral equation formalism polarizable continuum model (IEFPCM). Tautomerism of 1-(2-benzothiazolyl)-3-methyl-4-(2-thiazolylazo)pyrazol-5-one has been examined by means of B3LYP/6-31+G(d) method. Calculated absorption maxima are evaluated via comparison with experimental values.

Synthesis, Characterization and Antimicrobial Activity of Heterocyclic Azodyes Derived from Thiadiazole

Ethyl-1,3,4-thiadiazole-2-amine have been synthesized by single step reaction. A series of heterocyclic azodyes were synthesized by coupling 8-hydroxyquinoline, 2,6-diaminopyridine, N,N -dimethyl aniline, 2-napthol and resorcinol with diazotized 5-ethyl-1,3,4-thiadiazol-2-amine in nitrosyl sulphuric acid. These dyes were characterized by UV, IR, 1 H NMR, 13 C NMR, elemental analysis and mass spectrometry for selected dyes. The synthesized compounds were also screened for biological activity.

Synthesis, Characterization, and Biological Activity of 5-Phenyl-1,3,4-thiadiazole-2-amine Incorporated Azo Dye Derivatives

5-Phenyl-1,3,4-thiadiazole-2-amine has been synthesized by single step reaction. A series of heterocyclic azodyes were synthesized by diazotisation of 5-phenyl-1,3,4-thiadiazole-2-amine by nitrosyl sulphuric acid followed by coupling with different coupling compounds such as 8-hydroxyquinoline, 2,6-diaminopyridine, 2-naphthol, N,N-dimethyl aniline, resorcinol, and 4,6-dihydroxypyrimidine. The dyes were characterized by UV-Vis, IR, 1H-NMR, 13C NMR, and elemental analysis. The synthesized compounds were also screened for biological activity.

Hetarylazoindoles 2. Spectroscopic and structural investigation of new benzothiazolylazo indole dyes

Synthesis of new benzothiazolylazo indole dyes were carried out by diazotization of 2-aminobenzothiazole, 6- and 5,6-disubstituted 2-aminobenzothiazoles using with nitrosyl sulfuric acid and coupling with various 2- and 1,2-disubstituted indole derivatives. The structures of the dyes were characterized by UV–vis, FT-IR, 1H NMR, mass spectroscopic techniques and elemental analysis. Their solvatochromic properties in different solvents were investigated and their absorption spectra were found to be solvent dependent. The azo-hydrazone tautomerism was discussed in relation to solvent and substituent effects. In addition, acid–base effect on this equilibrium was also evaluated. To determine the most tautomeric form of the prepared dyes in solid state, X-ray data for 2-Methyl-3-(6-methoxybenzothiazol-2-yldiazenyl)-1H-indole were recorded in different solvents. The X-ray results showed that the dye was stable as azo tautomer in the solid state.

Synthesis, spectral properties, biological activity and application of new 4-(benzyloxy)phenol derived azo dyes for polyester fiber dyeing

A series of hetaryl-azophenol dyes were prepared by coupling 4-benzyloxyphenol with eight heterocyclic amines in nitrosyl sulphuric acid. The structure of the prepared azo dyes was characterized by UV-Vis, FT-IR and 1H-NMR spectroscopic techniques, as well as elemental analysis (CHN). The solvatochromism of dyes was evaluated with respect to the wavelength of maximum absorption (λmax) in various solvents. The effects of temperature, concentration as well as acid and base on the visible absorption maxima are also reported. The newly synthesized dyes were screened for their potential antibacterial activities against four bacterial species and the results revealed significant activity against the test microorganisms in vitro. In addition, the dyes were applied to polyesters and afforded red-orange shades with excellent wash fastness properties.