10025-85-1Relevant articles and documents
Electrochemical behavior of chloramines on the rotating platinum and gold electrodes
Piela, Barbara,Wrona, Piotr K.
, p. E255-E265 (2003)
Electroreduction of chloramines (mono-, di-, and trichloramine) in 1 M NH4Cl solutions of different pH was investigated at the rotating platinum and gold electrodes. It was found that all chloramines are present in the solution in nonprotonated forms and give well-formed one-step or two-step current-potential waves. The final products of reduction are ammonium (or ammonia) and chloride ions. Monochloramine is reduced in a single two-electron irreversible wave. Hydrazine is not an intermediate in monochloramine reduction. Dichloramine reduction generally proceeds in two two-electron steps (via monochloramine). Below pH 4.3 a kinetic current due to the protonated dichloramine reduction (single four-electron wave) is in force, appearing as an increase of the height of the first step on lowering pH. Due to this process below pH 2.5 only one four-electron reduction wave is observed. Trichloramine reduction occurs in two steps: two-electron trichloramine to dichloramine reduction and four-electron dichloramine reduction. In strong acidic solutions the kinetic current due to the protonated trichloramine reduction has to be taken into account. A reaction mechanism common for all chloramines was proposed with [NXCl·] as an intermediate (X = H2, HCl, and Cl2 for mono-, di-, and trichloramine, respectively). The rate-determining step does not involve proton transfer.
Energetics of halogen amine reactions with triplet metastables: NFCl2 with Ar(3P0,2), He(23S), and N2(3Σ+u) and NCl3 with Ar(3P0,2)
Gershanovich,Gilbert
, p. 840 - 848 (1997)
The collisions of NFCl2 with the metastable species Ar(3P0,2), He(23S, 21S), and N2(3Σ+u) and of NF2Cl and NCl3 with Ar(3P0,2) were carried out using a discharge flow system, and diatomic product channels were identified on the basis of emission from the fragments. The mechanisms for these reactions were determined from the emission spectra of the products, the energy available in the reacting species and released in the fragments, and the conservation of spin angular momentum. To carry out the energy analysis, the ΔHform's of NF2Cl, NFCl2, and NCl3 were calculated using G1 and G2 methods with Gaussian 94, yielding average theoretical values of -5.3, 23.0, and 48.3 kcal/mol, respectively. These values are compared to estimated experimental ΔHform's which have been reported for NF2Cl and NCl3.
VIBRATIONAL SPECTRA AND FORCE CONSTANTS FOR THE MOLECULAR SERIES NH3-nCln
Sawodny, Wolfgang,Haertner, Heinz,Minkwitz, Rolf,Bernstein, Dirk
, p. 145 - 154 (1989)
The IR spectrum of NCl3 has been remeasured in an N2 matrix and reassigned.Force constants have been calculated by ab initio methods for the molecular series NH3-nCln.For the still unknown HNCl2, the force field was used to calculate
The mechanism of monochloramine disproportionation under acidic conditions
Fehér, Péter Pál,Purgel, Mihály,Lengyel, Adrienn,Stirling, András,Fábián, István
, p. 16713 - 16721 (2019)
Monochloramine is a widely employed agent in water treatment technologies. However, its utilization has some drawbacks like the transformation of the active species into the undesired dichloramine. Although it is more pronounced in acidic solutions, the f
Photolysis of Nitrogen Trichloride
Gilbert, J. V.,Wu, X. L.,Stedman, D. H.,Coombe, R. D.
, p. 4265 - 4269 (1987)
Spectra and time profiles of the emission resulting from pulsed irradiation of NCl3 at 248 and 308 nm were collected and analyzed.Two distinct spectral features were observed, one a long series of bands separated by 320 +/- 30 cm-1, the second an unresolved emission underlying the bands.The two features exhibit different time behavior and lifetimes in the limit of zero pressure.The photochemistry is interpreted via a model which involves the interaction of three electronic states of NCl3.
The role of cobalt oxide or magnesium oxide in ozonation of ammonia nitrogen in water
Anggo Krisbiantoro, Philip,Togawa, Tomokazu,Mahardiani, Lina,Aihara, Haruka,Otomo, Ryoichi,Kamiya, Yuichi
, (2020/03/23)
In this study, the reaction mechanisms for ozonation of ammonia nitrogen in the presence of Co3O4 or MgO were investigated. For the reaction over Co3O4, Cl– in the reaction solution was indispensable and ClO– was formed by a non-catalytic oxidation of Cl–. Co3O4 promoted the reaction of NH4+ with ClO– to give the products including NO3–, chloramines and gaseous products. In contrast, Cl– was unnecessary for the reaction with MgO. pH of the reaction solution was maintained at around 9 throughout the reaction owing to partial dissolution of MgO. Ammonia nitrogen was decomposed to mainly NO3– by non-catalytic radical reaction involving OH·, which was formed by the reaction of OH– with O3 in weakly basic solution. To keep the reaction solution weakly basic, H+ formed with the decomposition of NH4+ was neutralized. As a result, about the same amount of Mg2+ as that of decomposed ammonia nitrogen was dissolved.
Diamondoid derivatives possessing therapeutic activity in the treatment of neurologic disorders
-
Page/Page column 25, (2008/06/13)
This invention relates to diamondoid derivatives which exhibit therapeutic activity. Specifically, the diamondoid derivatives herein exhibit therapeutic effects in the treatment of neurologic disorders. Also provided are methods of treatment, prevention a
Non-metal redox kinetics: Oxidation of bromide ion by nitrogen trichloride
Gazda, Michael,Kumar, Krishan,Margerum, Dale W.
, p. 3536 - 3542 (2008/10/08)
Bromide ion reacts with NCl3 to generate NBrCl2 with the rate expression d[NCl3]/dt = 12[Br-][NCl3] (M s-1 at 25.0°C, μ = 0.50 M). The NBrCl2 intermediate subsequently reacts with Br- to give N2, Br2, and Cl- with the rate expression -d[NBrCl2]/dt = (0.05 + 5.3[Br-])[NBrCl2]. The overall stoichiometry from pH 3.2 to 6.5 corresponds to 2NCl3 + 6Br- → N2 + 3Br2 + 6Cl-. Rate constants for NCl3 reactions show extreme sensitivity to nucleophilic strength with SO32- > CN- > I- ? Br-. Aqueous absorption spectra are determined for NCl3 with maxima at 336 nm (∈ 190 M-1 cm-1) and 220 nm (∈ 5320 M-1 cm-1) and for NBrCl2 with a maximum at 228 nm (∈ 4800 M-1 cm-1). Spectral bands for NCl3, NBrCl2, NBr2Cl, and NBr3 shift systematically with the number of bromine atoms from 220 to 256 nm. The rate constants for the reactions of NHCl2 with Br2, HOBr, and Br- are much larger than that for the reaction of NCl3 with Br-.
Non-metal redox kinetics: Reactions of sulfite with dichloramines and trichloramine
Yiin, Boudin S.,Margerum, Dale W.
, p. 1942 - 1948 (2008/10/08)
Pulsed-accelerated-flow (PAF) and stopped-flow techniques are used to study the kinetics of HNCl2 and CH3NCl2 reactions with sulfite. Pseudo-first-order rate constants with excess sulfite at p[H+] 3.7-6.4 are measured from 35-45000 s-1 (25.0°C, μ = 0.50). Acid suppresses the rate because SO3H- is much less reactive than SO32-. The rate expression is -d[RNCl2]/dt = k1[RNCl2][SO32-], where k1 (M-1 s-1) is 5.8 × 106 for HNCl2 and 2.4 × 107 for CH3NCl2. The initial nitrogen product is RNHCl, which reacts further with sulfite. Trichloramine reactions with sulfite are measured by the PAF method under second-order conditions with unequal concentrations (25.0°C, μ = 0.50) from p[H+] 3.8 to 4.6. The rate expression is -d[NCl3]/dt = (k1[SO32-] + k2[SO3H-])[NCl3], where k1 is 4.5 × 109 M-1 s-1 and k2 is 1.4 × 107 M-1 s-1. The initial nitrogen product is HNCl2, which reacts further with sulfite. A Cl+-transfer mechanism is proposed for all the reactions with sulfite to give ClSO3- as an initial product that hydrolyzes to give Cl- and SO42-. The relative reactivities of active chlorine species with SO32- are NCl3 ? HNCl2 ? NH2Cl ? OCl-, where the NCl3 and HNCl2 reactions are suppressed by acid whereas the NH2Cl and OCl- reactions are acid assisted.
Non-metal redox kinetics: Reactions of trichloramine with ammonia and with dichloramine
Yiin, Boudin S.,Margerum, Dale W.
, p. 2135 - 2141 (2008/10/08)
Trichloramine reacts with excess NH3 and base (B) with the rate expression -d[NCl3]/dt = 2kB[B][NH3][NCl3], based on the overall stoichiometry 2NCl3 + 3NH3 + 3OH- → 3NH2Cl + N2 + 3Cl- + 3H2O. The reaction is general-base assisted with kB values (M-2 s-1, 25.0°C, μ = 0.50 M) of 4.46 × 103 for OH-, 3.3 × 103 for PO43-, and 22 for NH3. A water path with kH2O = 2.2 M-1 s-1 and an acidic phosphate path for H2PO4- (kHB = 450 M-2 s-1) are also found. The rate-determining step in the proposed mechanism is a Cl+ transfer between NCl3 and NH3 to give HNCl2 and NH2Cl. This is followed by N2 formation in a rapid base-assisted reaction between NCl3 and HNCl2 with the rate expression -d[NCl3]/dt = kB′[B][HNCl2][NCl3], based on the stoichiometry NCl3 + HNCl2 + 3OH- → N2 + 2HOCl + 3Cl- + H2O. Values of kB′ (M-2 s-1, 25.0°C, μ = 0.50 M) are 2.92 × 104 for HPO42- and greater than 4 × 107 for OH-. The HOCl released in the formation of N2 reacts with excess NH3 to give more NH2Cl, which accounts for the overall stoichiometry of 1.5 NH2Cl formed per NCl3. The reaction between NCl3 and HNCl2 is of critical importance in the explanation of breakpoint chlorination processes.
