Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-...Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-linked-immunoassay(ELISA)method was developed to determine 3-NT in modified model protein(bovine serum albumin,BSA)and ambient aerosol samples.The nitration degrees(NDs)of BSA in the exposure experiments with different durations were detected by both the ELISA and spectrophotometric methods(i.e.,ND_(ELISA) and ND_(SEC-PDA)),which show good coincidence.The kinetic investigation by both ΔND_(ELISA) and ΔND_(SEC-PDA) in the exposure experiments shows that the rate coefficients(k)of the pseudo-first-order kinetic rate reactions of protein nitration were comparable.These results indicate that direct detection of 3-NT by the ELISA method can be applied for laboratory exposure samples analysis for kinetic studies.Based on the selective detection of 3-NT,ND_(ELISA) provides a promising measure for the assessment of ND in model proteins.3-NT was alsomeasured in PM_(2.5) samples in summer in Guangzhou,southern China,ranging from 10.1 to 404 pg/m^(3),providing clear evidence of protein nitration in ambient aerosols.We further proposed that 3-NT/protein can be used as a proxy to evaluate protein nitration in ambient aerosols.A significant correlationwas observed between 3-NT/protein and O_(3),confirming the crucial role of O_(3) in protein nitration.Our results show that the direct detection of 3-NT by the ELISA method can be more widely applied in the laboratory and field-based studies for understanding the mechanisms of protein nitration.展开更多
CeO_(2)-based catalysts are widely investigated for selective catalytic reduction(SCR)of NO with NH3.Interaction of NO/O_(2) with CeO_(2) generally produces two surface species,i.e.,nitrates and nitrites.However,the e...CeO_(2)-based catalysts are widely investigated for selective catalytic reduction(SCR)of NO with NH3.Interaction of NO/O_(2) with CeO_(2) generally produces two surface species,i.e.,nitrates and nitrites.However,the explicit quantification of these two species is still unresolved.Herein,we reported that spectrophotometry characterization was effective in determining surface adsorbed NOx species on CeO_(2) by measuring the corresponding ions(NO_(2)-and NO_(3)^(-))dissolved in aqueous solution.Experimental results show that both nitrate(-NO_(3))and nitrite(-NO_(2))species can be quantitatively evaluated and the accuracy is verified by calibrating with NOx-TPD result.Exclusive transfer of adsorbed NOx from catalyst surface to aqueous solution is confirmed and the dissolution process can be accelerated by ultrasonic treatment.Moreover,useful information related to evolution of surface NOx species under various conditions(O_(2) treatment,different adsorption temperature and duration)and over different catalysts(Fe_(2)O_(3),MnO_(2) and MnOx—CeO_(2))are provided.The result of present study demonstrates the potential of spectrophotometry for quantitative discrimination of surface NOx species on CeO_(2) and other oxide-based materials,which is conducive to mechanism analysis of SCR reaction.展开更多
Many derivatives of industrially useful cellulose have hydroxyls of the anhydroglucose(AHG) units uncompletely substituted. Since each AHG unit of a cellulose molecule is a trihydric alcohol,consisted of one primary(p...Many derivatives of industrially useful cellulose have hydroxyls of the anhydroglucose(AHG) units uncompletely substituted. Since each AHG unit of a cellulose molecule is a trihydric alcohol,consisted of one primary(position 6) and two secondary hydroxyl groups(positions 2 and 3), the distribution of substituents in these trihydric alcohol units could be different for different derivatives. The展开更多
In this paper, the nitration characteristic of alcohols with mixed acid for the synthesis of energetic mate-rials in a stainless steel microreactor was investigated experimentally. The nitration of iso-octanol with HN...In this paper, the nitration characteristic of alcohols with mixed acid for the synthesis of energetic mate-rials in a stainless steel microreactor was investigated experimentally. The nitration of iso-octanol with HNO3-H2SO4 mixed acid was chosen as a typical model reaction which involved fast and strong exothermic liquid-liquid heterogeneous reaction process. The influences of mixed acid composition, flow rate, organic/aqueous flow ratio and reaction temperature have been investigated. The results indicated that the reaction could be con-ducted safely and stably in the microreactor at 25-40°C, which are enhanced compared to 15°C or below for safe operating conditions in the conventional reactors. Moreover, the 98.2% conversion of iso-octanol could be obtained and no by-products were detected in all cases.展开更多
Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature.
A selective and efficient process for the electrophilic nitration is described using N_2O_5 as a green nitrating agent,Hβ zeolite as a solid acid catalyst and shape controlling agent under mild conditions.
Certain phenols and naphthols were nitrated regioselectively with Zn(NO)·6HO/TCT in acetonitrile as solvent at room temperature and short reaction time in good yields.The reaction condition was mild.TCT is a chea...Certain phenols and naphthols were nitrated regioselectively with Zn(NO)·6HO/TCT in acetonitrile as solvent at room temperature and short reaction time in good yields.The reaction condition was mild.TCT is a cheap and commercially available reagent.It performed as an acid catalyst in this transformation.展开更多
A mild,efficient and regioselective method for the mononitration of phenolic compounds is described using bismuth subnitrate/ charcoal in the presence of trichloroisocyanuric acid in CH2Cl2 at room temperature.
Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)...Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)and Fourier Transform Infrared Spectroscopy(FTIR)techniques.X-ray parameters of coal like interlayer spacing(d_(002)),crystallite size(L_(c)),aroamticity(f_(a)),average number of aromatic layers(N_(c)),and coal rank(I_(26)/I_(20))have been determined using profilefitting software.Considerable variation is observed in treated coals in comparison to the demineralized coals.The d_(002)values of treated coals have increased in both the media showing increase in disordering of organic moieties.A linear relationship has been observed between d_(002)values with the volatile matter of the coals.Similarly,the d_(002)values show linear relationship with C_(dmf) contents for demineralized as well as for the treated coals in both the media.The L_(c) and N_(c) values have decreased in treated coals corresponding to demineralized coals.The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity(f_(a))increases with increase in rank and shows a linear relationship with the vitrinite reflectance.The corresponding I_(26)/I_(20)values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium.FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals(SMCs)in both the media,the corresponding bands at 1550-1490 and 1355-1315 cm^(-1) respectively.FTIR study confirms that nitration is the predominant phenomenon,though,oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs.In comparison to raw coals,the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.展开更多
A mixture of guanidinium nitrate and silica sulfuric acid acts as mild and heterogeneous media for the efficient mono nitration of phenolic compounds in dichloromethane at room temperature.
A mild,efficient and eco-friendly process for the electrophilic nitration is described using N_2O_5 as a green nitrating agent in the presence of rare earth metal triflates[RE（OTf）_3]under mild conditions.
The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO3) binary reagent and zinc chloride (ZnCl2) were reported here as a homogeneous nit...The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO3) binary reagent and zinc chloride (ZnCl2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition, fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development, which needs to be studied as part of future investigations.展开更多
Experimental results in this work demonstrate that PW12-H2SO4/SiO2 catalyst is a good and durable catalyst for vapor phase nitration of benzene to nitrobenzene (NB) using 65% nitric acid at normal pressure. It retains...Experimental results in this work demonstrate that PW12-H2SO4/SiO2 catalyst is a good and durable catalyst for vapor phase nitration of benzene to nitrobenzene (NB) using 65% nitric acid at normal pressure. It retains the advantages of using H2SO4 as catalyst and the addition of phosphotungstic acid holds back the effusion of sulfuric acid. This new catalyst keeps high activity (the conversion of HNO3 is more than 92%), high selectivity of NB (more than 97%) and high space time yield (STY 1.5 kg NB/kg cat.h) even after 150 h on stream, under condition of 423 K, SV=3200 ml/g h.展开更多
Nitration of aromatic Compounds is triggered by Vilsmeier-Haack reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of KNO3 or NaNO2 under conventional and non-conventional conditions. The reactions af- forded correspo...Nitration of aromatic Compounds is triggered by Vilsmeier-Haack reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of KNO3 or NaNO2 under conventional and non-conventional conditions. The reactions af- forded corresponding Nitro derivatives in very good yield with high regioselectivity. The results obtained in non-conventional methods (Micro wave irradiation, Grinding, Sonication) are comparable with those ob- tained under conventional conditions, but the reaction times of former conditions are substantially shorter than that of the latter.展开更多
This procedure works efficiently for high selective mono nitration of phenol and substituted phenol to corresponding nitro compounds in moderate to high yield using poly（4-vinylpyridinium nitrate） and silica sulfuri...This procedure works efficiently for high selective mono nitration of phenol and substituted phenol to corresponding nitro compounds in moderate to high yield using poly（4-vinylpyridinium nitrate） and silica sulfuric acid in dichloromethane at room temperature.展开更多
Solvent – free Mortar-pestle (grinding) and microwave-assisted nitration reactions (MWANR’s) underwent smoothly in the presence of group V and VI metal salts with high regio-selectivity for anilides, moderately- and...Solvent – free Mortar-pestle (grinding) and microwave-assisted nitration reactions (MWANR’s) underwent smoothly in the presence of group V and VI metal salts with high regio-selectivity for anilides, moderately- and non-activated aro-matic compounds. The reactions were conducted under solvent-free conditions, which afforded good to excellent yields. The observed reaction times in MW assisted conditions are in the range of only few minutes.展开更多
Thiourea nitrate （TN） was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent, Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied...Thiourea nitrate （TN） was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent, Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied, TN could convert aromatic compounds to the corresponding nitrated derivatives with various abnormal yields under mild conditions. The results suggested that the reaction mechanism might be different from those of traditional nitration reagents.展开更多
Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e...Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e., 2,6-diamino-3,5-dinitropyridine(DADNP). The active intermediates determining the product selectivity are theoretically studied. The HSO_(4)^(-)-NO_(2)^(+) complex is proposed as the dominant active nitrating intermediate for the first time, which shows low energy barrier(i.e., 10.19 kcal·mol^(-1),1 kcal = 4.186 k J) for direct dinitration of DAP to DADNP. The formed water during the reaction results in not only the formation of less active SO_(4)^(2-)-NO_(2)^(+) complex, but also the occurance of DAP sulfonation(DAP-SO_(3)H intermediate)to facilitate the formation of mononitration byproduct. Meanwhile, the accompanied thermal effects cause the generation of undesirable pyridine-NHNO_(2) intermediate, which is difficult to be rearranged to yield DADNP, inhibiting the reaction and thus giving low DAP conversion. The insights reported here elucidates the importance of thermal effects elimination and water content control, confirmed experimentally in the batch-and micro-reaction systems.展开更多
A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to th...A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to the traditional nitration protocols.展开更多
Melamine and poly vinylpyrrolidone （PVP） reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-（H2SO4）3 and PVP-（H2SO4）n. These solid acids were used for the first nitration...Melamine and poly vinylpyrrolidone （PVP） reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-（H2SO4）3 and PVP-（H2SO4）n. These solid acids were used for the first nitration of bisphenol A as well as other phenols in the presence of NHaNO3. Mono- and di-nitro bisphenol A have been characterized with IR and ^1H NMR techniques.展开更多
基金supported by the National Natural Science Foundation of China(No.41975156).
文摘Tyrosine residues in proteins can be nitrated to form 3-nitrotyrosine(3-NT)under the influence of ozone(O_(3))and nitrogen dioxide(NO_(2))in the air,which may introduce health impacts.A selective and sensitive enzyme-linked-immunoassay(ELISA)method was developed to determine 3-NT in modified model protein(bovine serum albumin,BSA)and ambient aerosol samples.The nitration degrees(NDs)of BSA in the exposure experiments with different durations were detected by both the ELISA and spectrophotometric methods(i.e.,ND_(ELISA) and ND_(SEC-PDA)),which show good coincidence.The kinetic investigation by both ΔND_(ELISA) and ΔND_(SEC-PDA) in the exposure experiments shows that the rate coefficients(k)of the pseudo-first-order kinetic rate reactions of protein nitration were comparable.These results indicate that direct detection of 3-NT by the ELISA method can be applied for laboratory exposure samples analysis for kinetic studies.Based on the selective detection of 3-NT,ND_(ELISA) provides a promising measure for the assessment of ND in model proteins.3-NT was alsomeasured in PM_(2.5) samples in summer in Guangzhou,southern China,ranging from 10.1 to 404 pg/m^(3),providing clear evidence of protein nitration in ambient aerosols.We further proposed that 3-NT/protein can be used as a proxy to evaluate protein nitration in ambient aerosols.A significant correlationwas observed between 3-NT/protein and O_(3),confirming the crucial role of O_(3) in protein nitration.Our results show that the direct detection of 3-NT by the ELISA method can be more widely applied in the laboratory and field-based studies for understanding the mechanisms of protein nitration.
基金Project supported by the National Natural Science Foundation of China(22276097,21976081)the Major Scientificand Technological Project of Bingtuan(2018AA002)。
文摘CeO_(2)-based catalysts are widely investigated for selective catalytic reduction(SCR)of NO with NH3.Interaction of NO/O_(2) with CeO_(2) generally produces two surface species,i.e.,nitrates and nitrites.However,the explicit quantification of these two species is still unresolved.Herein,we reported that spectrophotometry characterization was effective in determining surface adsorbed NOx species on CeO_(2) by measuring the corresponding ions(NO_(2)-and NO_(3)^(-))dissolved in aqueous solution.Experimental results show that both nitrate(-NO_(3))and nitrite(-NO_(2))species can be quantitatively evaluated and the accuracy is verified by calibrating with NOx-TPD result.Exclusive transfer of adsorbed NOx from catalyst surface to aqueous solution is confirmed and the dissolution process can be accelerated by ultrasonic treatment.Moreover,useful information related to evolution of surface NOx species under various conditions(O_(2) treatment,different adsorption temperature and duration)and over different catalysts(Fe_(2)O_(3),MnO_(2) and MnOx—CeO_(2))are provided.The result of present study demonstrates the potential of spectrophotometry for quantitative discrimination of surface NOx species on CeO_(2) and other oxide-based materials,which is conducive to mechanism analysis of SCR reaction.
文摘Many derivatives of industrially useful cellulose have hydroxyls of the anhydroglucose(AHG) units uncompletely substituted. Since each AHG unit of a cellulose molecule is a trihydric alcohol,consisted of one primary(position 6) and two secondary hydroxyl groups(positions 2 and 3), the distribution of substituents in these trihydric alcohol units could be different for different derivatives. The
基金Supported by the National Natural Science Foundation of China (20490208)the National High Technology Research and Development Program of China (2007AA030206)the Open Fund of State Key Laboratory of Explosion Science and Technology,BIT (KFJJ06-1)
文摘In this paper, the nitration characteristic of alcohols with mixed acid for the synthesis of energetic mate-rials in a stainless steel microreactor was investigated experimentally. The nitration of iso-octanol with HNO3-H2SO4 mixed acid was chosen as a typical model reaction which involved fast and strong exothermic liquid-liquid heterogeneous reaction process. The influences of mixed acid composition, flow rate, organic/aqueous flow ratio and reaction temperature have been investigated. The results indicated that the reaction could be con-ducted safely and stably in the microreactor at 25-40°C, which are enhanced compared to 15°C or below for safe operating conditions in the conventional reactors. Moreover, the 98.2% conversion of iso-octanol could be obtained and no by-products were detected in all cases.
文摘Nitro aromatic compound can be obtained in high yields via nitration of aromatic compound with wet carbon-based solid acid and NaNO_3 under solvent free oxidation at room temperature.
基金the financial support from the National Natural Science Foundation of China-Academy of Engineering Physics(No.10976014)the Natural Science Foundation of Jiangsu Province(No.BK2011697)Independent Scientific Research Special Plan of NJUST(No.2011YBXM06)
文摘A selective and efficient process for the electrophilic nitration is described using N_2O_5 as a green nitrating agent,Hβ zeolite as a solid acid catalyst and shape controlling agent under mild conditions.
文摘Certain phenols and naphthols were nitrated regioselectively with Zn(NO)·6HO/TCT in acetonitrile as solvent at room temperature and short reaction time in good yields.The reaction condition was mild.TCT is a cheap and commercially available reagent.It performed as an acid catalyst in this transformation.
基金Financial support by DUBS Research Council is gratefully acknowledged
文摘A mild,efficient and regioselective method for the mononitration of phenolic compounds is described using bismuth subnitrate/ charcoal in the presence of trichloroisocyanuric acid in CH2Cl2 at room temperature.
基金We thank the Director,CSIR-Central Institute of Mining and Fuel Research,Dhanbad for permission to publish this paper.We also thank our colleagues at the Resource Quality Assessment and CTL Research Group for their support.
文摘Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRD)and Fourier Transform Infrared Spectroscopy(FTIR)techniques.X-ray parameters of coal like interlayer spacing(d_(002)),crystallite size(L_(c)),aroamticity(f_(a)),average number of aromatic layers(N_(c)),and coal rank(I_(26)/I_(20))have been determined using profilefitting software.Considerable variation is observed in treated coals in comparison to the demineralized coals.The d_(002)values of treated coals have increased in both the media showing increase in disordering of organic moieties.A linear relationship has been observed between d_(002)values with the volatile matter of the coals.Similarly,the d_(002)values show linear relationship with C_(dmf) contents for demineralized as well as for the treated coals in both the media.The L_(c) and N_(c) values have decreased in treated coals corresponding to demineralized coals.The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity(f_(a))increases with increase in rank and shows a linear relationship with the vitrinite reflectance.The corresponding I_(26)/I_(20)values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium.FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals(SMCs)in both the media,the corresponding bands at 1550-1490 and 1355-1315 cm^(-1) respectively.FTIR study confirms that nitration is the predominant phenomenon,though,oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs.In comparison to raw coals,the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.
基金supported by the research affairs of Ilam University,Ilam,Iran
文摘A mixture of guanidinium nitrate and silica sulfuric acid acts as mild and heterogeneous media for the efficient mono nitration of phenolic compounds in dichloromethane at room temperature.
基金the financial support from the National Nature Science Foundation of China Academy of Engineering Physics(No.10976014)Nature Science Foundation of Jiangsu Province(No.BK2011697)
文摘A mild,efficient and eco-friendly process for the electrophilic nitration is described using N_2O_5 as a green nitrating agent in the presence of rare earth metal triflates[RE（OTf）_3]under mild conditions.
文摘The development of a new silane reagent derived from tetrachlorosilane (TCS) was applied in the present work. TCS-sodium nitrate (NaNO3) binary reagent and zinc chloride (ZnCl2) were reported here as a homogeneous nitrating system. The later was used for the efficient mono nitration, in most cases, with high para-regioselectivity. The nitration proceeded smoothly under mild condition, fairly clean and in good yields. This readily available and inexpensive system is superior to other methods by avoidance of the use of corrosive nitrating reagents and therefore considered to be convenient in terms of risk reduction, economic advantages and environment protection. The present protocol was convenient and applicable to a variety of aromatic hydrocarbons and could be amenable to high throughput synthesis of combinatorial libraries for potential drug development, which needs to be studied as part of future investigations.
文摘Experimental results in this work demonstrate that PW12-H2SO4/SiO2 catalyst is a good and durable catalyst for vapor phase nitration of benzene to nitrobenzene (NB) using 65% nitric acid at normal pressure. It retains the advantages of using H2SO4 as catalyst and the addition of phosphotungstic acid holds back the effusion of sulfuric acid. This new catalyst keeps high activity (the conversion of HNO3 is more than 92%), high selectivity of NB (more than 97%) and high space time yield (STY 1.5 kg NB/kg cat.h) even after 150 h on stream, under condition of 423 K, SV=3200 ml/g h.
文摘Nitration of aromatic Compounds is triggered by Vilsmeier-Haack reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of KNO3 or NaNO2 under conventional and non-conventional conditions. The reactions af- forded corresponding Nitro derivatives in very good yield with high regioselectivity. The results obtained in non-conventional methods (Micro wave irradiation, Grinding, Sonication) are comparable with those ob- tained under conventional conditions, but the reaction times of former conditions are substantially shorter than that of the latter.
基金supported by the research affairs of Ilam University,Ilam,Iran
文摘This procedure works efficiently for high selective mono nitration of phenol and substituted phenol to corresponding nitro compounds in moderate to high yield using poly（4-vinylpyridinium nitrate） and silica sulfuric acid in dichloromethane at room temperature.
文摘Solvent – free Mortar-pestle (grinding) and microwave-assisted nitration reactions (MWANR’s) underwent smoothly in the presence of group V and VI metal salts with high regio-selectivity for anilides, moderately- and non-activated aro-matic compounds. The reactions were conducted under solvent-free conditions, which afforded good to excellent yields. The observed reaction times in MW assisted conditions are in the range of only few minutes.
基金Fundamental Research Funds for the Central Universities(2011)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,PR China(2011)for the financial support
文摘Thiourea nitrate （TN） was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent, Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied, TN could convert aromatic compounds to the corresponding nitrated derivatives with various abnormal yields under mild conditions. The results suggested that the reaction mechanism might be different from those of traditional nitration reagents.
基金financially supported by the National Natural Science Foundation of China, China (21922803, 22122807, and 22008072)the Innovation Program of Shanghai Municipal Education Commission, China+1 种基金the Program of Shanghai Academic/Technology Research Leader, China (21XD1421000)the China Postdoctoral Science Foundation, China (2020M671025 and 2019TQ0093)。
文摘Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e., 2,6-diamino-3,5-dinitropyridine(DADNP). The active intermediates determining the product selectivity are theoretically studied. The HSO_(4)^(-)-NO_(2)^(+) complex is proposed as the dominant active nitrating intermediate for the first time, which shows low energy barrier(i.e., 10.19 kcal·mol^(-1),1 kcal = 4.186 k J) for direct dinitration of DAP to DADNP. The formed water during the reaction results in not only the formation of less active SO_(4)^(2-)-NO_(2)^(+) complex, but also the occurance of DAP sulfonation(DAP-SO_(3)H intermediate)to facilitate the formation of mononitration byproduct. Meanwhile, the accompanied thermal effects cause the generation of undesirable pyridine-NHNO_(2) intermediate, which is difficult to be rearranged to yield DADNP, inhibiting the reaction and thus giving low DAP conversion. The insights reported here elucidates the importance of thermal effects elimination and water content control, confirmed experimentally in the batch-and micro-reaction systems.
基金support by New-Shoot Talented Man Plan Project of Zhejiang Province(No. 2011R429012)
文摘A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to the traditional nitration protocols.
基金financial support for this work from the research affairs of Hamedan University of Medical Sciences, Hamedan,I.R.Iran and partial support of this work by the Research Affairs Office of Bu-Ali Sina University(Grant number 32-1716 entitled development of chemical methods,reagent and molecules.) Hamedan,I.R.Iran
文摘Melamine and poly vinylpyrrolidone （PVP） reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-（H2SO4）3 and PVP-（H2SO4）n. These solid acids were used for the first nitration of bisphenol A as well as other phenols in the presence of NHaNO3. Mono- and di-nitro bisphenol A have been characterized with IR and ^1H NMR techniques.
