14989-30-1Relevant articles and documents
Connick, R. E.
, p. 1509 - 1514 (1947)
Zimmermann, C.,Strong, F. C.
, p. 2063 - 2066 (1957)
Heterogeneous Reactions of Chlorine Nitrate and Hydrogen Chloride on Type I Polar Stratospheric Clouds
Leu, Ming-Taun,Moore, Steven B.,Keyser, Leon F.
, p. 7763 - 7771 (1991)
The heterogeneous reactions ClONO2 + HCl -> Cl2 + HNO3 (1) and ClONO2 + H2O -> HOCl + HNO3 (2) on vapor-deposited HNO3-H2O ice substrates have been investigated at 196 K by using a fast-flow reactor coupled with a quadrupole mass spectrometer.The reaction probability for (1) is 0.10 +/- 0.02 and independent of both the HNO3 and HCl concentrations in the substrate compositions studied.For (2), the reaction probability is approximately 1 * 10-5 near 53.8 wtpercent HNO3, the composition of pure nitric acid trihydrate (NAT), and is about 1 * 10-3 at 46 wtpercent HNO3.The sticking coefficient of HCl on these substrates was also found to be strong function of the substrate composition, ranging from about 2 * 10-5 at NAT composition to 6 * 10-3 at 45 wtpercent HNO3.The HNO3-H2O ice substrates were found to have large internal surface areas, and corrections for gas-phase diffusion within the porous ices were applied to observed loss rates.The large decrease in the HCl sticking coefficient and the reaction probability for (2) as the composition of pure NAT is approached from the water-enriched side can be semiquantitatively explained in terms of a simple two-solid-phase model.Finally, the relation of these results to the depletion of polar ozone is discussed.
Makower, B.,Bray, W. C.
, p. 4765 - 4776 (1933)
Lifshitz, A.,Perlmutter-Hayman, B.
, p. 701 - 705 (1962)
Lifshitz, A.,Perlmutter-Hayman, B.
, p. 753 - 757 (1961)
State selected unimolecular dissociation of HOCl near threshold: The 6vOH vibrational state
Dutton, Gregory,Barnes, Rhett James,Sinha, Amitabha
, p. 4976 - 4992 (1999)
The spectroscopy and unimolecular dissociation dynamics of HOCl are examined by accessing rotational resonances of the 6vOH vibrational level over the Ka=0-5 manifolds using overtone-overtone double resonance. The spectroscopic analysis indicates that state mixing between the zeroth-order bright O-H stretching overtone state, 6 0 0, and dark background vibrational levels is incomplete as the bright state couples to only a fraction of the available states. The coupling of 6 0 0 to a set of nearby dark states is mediated primarily by anharmonic coupling with the fourth-order vibrational resonance k1,233 playing a particularly important role through its ability to couple the 6 0 0 state directly to the 5 2 1 vibration and indirectly to the 4 4 2 vibration. The measured state-specific unimolecular dissociation rates for 6 0 0 show large fluctuations with J and Ka and are substantially slower than that expected on the basis of statistical theory. The rate fluctuations are interpreted on the basis of spectroscopic data which suggest that the fluctuations arise as a result of variation in state mixing as different dark vibrational states come in and out of resonance with the bright state for different values of J and Ka.
Studies of reactions of importance in the stratosphere. IV. Rate constant for the reaction Cl + HOCl--> HCl + ClO over the temperature range 243-365 K
Cook, Jac-E L.,Ennis, Christine A.,Leck, Thomas J.,Birks, John W.
, p. 545 - 549 (1981)
The title reaction was studied over the temperature range 243-365 K using the discharge flow technique with mass spectrometry for detection.The rate constant was measured by detecting the loss of HOCl in the presence of a large excess of chlorine atoms.The resulting temperature dependent rate constant is given by k = (3.0 +/- 0.5) * 10-12exp cm3 molecule-1 s-1, where the stated errors include our estimate of the maximum possible systematic error.This reaction becomes a significant pathway to HCl in the stratosphere when the total ClX exceeds 10 ppbv.Upper limits for rate constants for the reactions HOCl + NO --> products and HOCl + O3 -> products at 300 K were established to be 1.0 * 10-17 and 4.0 * 10-16 cm3 molecule-1 s-1, respectively.
Anbar, M.
, p. 2031 - 2035 (1961)
The hydrolysis of chlorine nitrate on ice is autocatalytic
Geiger, Franz M.,Pibel, Charles D.,Hicks, Janice M.
, p. 4940 - 4945 (2001)
A key chemical reaction in stratospheric ozone depletion is the reaction of chlorine nitrate (ClONO2) with water. This reaction is known to be catalyzed in the presence of ice particles found in polar stratospheric clouds (PSCs). However, the mechanism and time scale of the reaction, and the role of the ice surface, are not well understood. This surface second harmonic generation study shows that the submonolayer ClONO2 hydrolysis on basal ice (Ih) surfaces at 185 K occurs autocatalytically, with the product molecule HOCl acting as the autocatalyst. The other product, HNO3, acts to delay the reaction. The hydrolysis reaction is surprisingly slow, with induction times that range from 100 to 1000 s, depending upon how much reactant is initially present. It is proposed that the ice surface serves as a reservoir, enabling the reaction to be acid catalyzed.
Chapman, D. L.,Vodden
, p. 138 - 138 (1909)
Reaction of ClONO2 with H2O and HCl in sulfuric acid and HNO3/H2SO4/H2O mixtures
Hanson, David R.
, p. 4794 - 4807 (1998)
Measurements of the reaction probabilities (γ) for ClONO2 onto sulfuric acid solutions at 200-270 K are described. ClONO2 uptake due to reaction with H2O and with HCl in H2SO4 solutions (45-55 wt percent) was investigated at 203-205 K. ClONO2 hydrolysis was also investigated on 36.5, 40, and 75 wt percent sulfuric acid solutions over a range of temperatures. The measured γ are generally in good agreement with previously reported values. In addition, the solubility of HCl was determined for 45 and 50 wt percent sulfuric acid from 200 to 225 K. The uptake of ClONO2 onto small sulfuric acid particles was studied resulting in a lower limit to the sticking coefficient of 0.5. ClONO2 reaction probabilities were also measured on H2SO4 solutions containing significant amounts of HNO3. In opposition to previous reports, HNO3 was found to have a significant effect on γ for ClONO2: it is as low as one-half of that expected for the comparable HNO3-free solutions. The measured γ on sulfuric acid solutions at 203 ± 2 K are discussed in terms of solubility, diffusivity, and bulk and surface reactions. Within this framework, the measured γ were fit as a function of H2SO4 and HCl content, thus allowing for the measurements to be extrapolated to atmospheric conditions.
Thermodynamic and kinetic properties of the reaction Cl + O2 + MClOO + M in the range 160-300 K and 1-1000 bar
Baer, S.,Hippler, H.,Rahn, R.,Siefke, M.,Seitzinger, N.,Troe, J.
, p. 6463 - 6470 (1991)
The reaction Cl + O2 + MClOO + M was studied by laser flash photolysis in the bath gases M = He, Ar, N2, and O2 over the temperature range 160-300 K and the pressure range 1-1000 bar.UV absorptions of ClOO were monitored, a maximum absorption cross section of ?(248 nm) = 3.4*10-17 cm2 was determined.An expression for the equilibrium constant Kp = 5.3*10-6 exp( + 23.4 kJ mol-1/RT) bar-1 was derived between 180 and 300 K, which, by a third law analysis, yields Η0 deg = -20.2 +/- 0.2 kJ mol-1.Limiting low pressure rate coefficients for Cl + O2 recombination of k0 = 8.8*10-34 (T/300 K)-3.0, k0 = 1.6*10-33 (T/300 K)-2.9, k0 = 1.4*10-33 (T/300 K)-3.9 cm6 s-1 were obtained over the range 160-260 K, as well as k0 (160 K) = 2.2*10-32 cm6 s-1.Rate constants for the reactions Cl + ClOO -> Cl2 + O2 or 2ClO, ClOO + ClOO -> products, and ClOO + Cl2 -> Cl2O + ClO were also derived.The recombination Cl + O2( + M) -> ClOO( + M) at pressures above 10 bar shows a transition to a high pressure plateau and, at pressures above 200 bar, to diffusion control.It is suggested that, like O + O2( + M) -> O3( + M), the reaction is governed by a radical complex mechanism.
Heterogeneous Reactions of ClONO2, HCl, and HOCl on Liquid Sulfuric Acid Surfaces
Zhang, Renyi,Leu, Ming-Taun,Keyser, Leon F.
, p. 13563 - 13574 (1994)
The heterogeneous reactions of ClONO2 + H2O -> HNO3 + HOCl (1), ClONO2 + HCl -> Cl2 + HNO3 (2), and HOCl + HCl -> Cl2 + H2O (3) on liquid sulfuric acid surfaces have been studied using a fast flow reactor coupled to a quadrupole mass spectrometer.The main objectives of the study are to investigate (a) the temperature dependence of these reactions at a fixed H2O partial pressure typical of the lower stratosphere (that is, by changing temperature at a constant water partial pressure, typical of the lower stratosphere that is by changing temperature at a constant water partial pressure, the H2SO4 content of the surfaces is also changed), (b) the relative importance or competition between reactions 1 and 2, and (c) the effect of HNO3 on the reaction probabilities due to the formation of a H2SO4/HNO3/H2O tern m.The measurements show that all the reactions depend markedly on temperature at a fixed H2O partial pressure: they proceed efficiently at temperatures near 200 K and much slower at temperatures near 220 K.The reaction probability (γ1) for ClONO2 hydrolysis approaches 0.01 at temperatures below 200 K, whereas the values for γ2 and γ3 are on the order of a few tenths at 200 K.Although detailed mechanisms for these reactions are still unknown, the present data indicate that the competition between ClONO2 hydrolysis and ClONO2 reaction with HCl may depend on temperature (or H2SO4 wt percent): in the presence of gaseous HCl at stratospheric concentrations, reaction 2 is dominant at lower temperatures (200 K), but reaction 1 becomes important at temperatures above 210 K.Furthermore, reaction probability measurements performed on the H2SO4/HNO3/H2O ternary solutions do not exhibit noticeable deviation from those performed on the H2SO4/H2O binary system, suggesting little effect of HNO3 in sulfate aerosols on the ClONO2 and HOCl reactions with HCL. The results reveal that significant reductions in the chlorine-containing reservoir species (such as ClONO2 and HCl) can take place on stratospheric sulfate aerosols at high latitudes in winter and early spring, even at temperatures too warm for polar stratospheric clouds (PSCs) to form or in regions where nucleation of PSCs is sparse.This is particularly true under elevated sulfuric acid loading, such as that after the eruption of Mt.Pinatubo.Comparisons between our results and those presently available have also been made.
Dees, H. M.,Parry, R. W.,Vidale, G. L.
, p. 5730 - 5734 (1956)
ESR spectrum of ClO (2Π3/2) isolated in a CO2 matrix
Trainer, M.,Helten, M.,Knapska, D.
, p. 3648 - 3653 (1983)
Upon isolation of ClO in a CO2 matrix at 10 K, a highly anisotropic ESR spectrum is observed which is attributed to ClO.This might be the first observation of a neutral radical with a 2Π ground state in a nonpolar matrix.Some of the structure discernible on the spectrum at 10 K may be related to ClO at different trapping sites.After annealing the sample at T > 45 K, the radical concentration diminishes and the g peak of the most prominent site splits into four peaks which may correspond to the hyperfine splitting of ClO.The spectrum can be explained by the following g and A tensors, gx = 1.889, gy = 1.899, gz = 2.66 and Ax = 111 MHz, Ay 20 MHz, Az 55 MHz.In a simple crystal field model these values are compared with molecular parameters of ClO deduced from gas phase spectra.
State selected unimolecular dissociation of HOCl
Barnes, Rhett James,Sinha, Amitabha
, p. 3730 - 3733 (1997)
The unimolecular decomposition of HOCl is investigated by exciting the molecule to the region of the sixth overtone of its OH stretching vibration (7νOH) using overtone-overtone double resonance.The excitation scheme is sufficiently selective to allow preparation of a single angular momentum quantum state within the 7νOH vibrational manifold lying ca. 2500 cm-1 above the dissociation limit.From the measured linewidths associated with the rotational features appearing in the action spectrum, we obtain an upper limit estimate for the dissociation rate of kuni9 s-1 which is substantially slower than that expected on the basis of RRKM theory.The nascent OH fragment product state distribution exhibit strong oscillations which depend on the rotational quantum numbers of the parent HOCl molecule.From the measured energy release associated with the OH fragment, the heat of formation of HOCl is estimated to be ΔH00(0K)=-16.7+/-0.6 kcal/mol.
Allmand,Cunliffe,Maddison
, p. 822 - 822 (1925)
AQUEOUS SOLUTION HAVING HYPOCHLOROUS ACID AS MAIN COMPONENT
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Paragraph 0038-0048, (2021/11/02)
PROBLEM TO BE SOLVED: To provide a solution having hypochlorous acid with improved storage stability as a main component. SOLUTION: The present invention discloses an aqueous solution having hypochlorous acid as a main component in which 40 mol% or more of the total sum of chlorine in the aqueous solution is chlorine of hypochlorous acid: particularly, an aqueous solution having hypochlorous acid as a main component in which 40 mol% or more of the total sum of chlorine in the aqueous solution is chlorine of hypochlorous acid, in which the total sum of alkali metal ions and alkaline earth metal ions is less than 1 mEq/L, and in which the total sum of negative ions in the aqueous solution other than hypochlorous acid is less than 10 mg/L, and which suppress metal corrosion. SELECTED DRAWING: None COPYRIGHT: (C)2022,JPOandINPIT
COMPOSITIONS OF HYPOCHLOROUS ACID(HOCl) AND METHODS OF MANUFACTURE THEREOF
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Paragraph 0029-0032, (2015/06/10)
The invention generally relates to compositions of hypochlorous acid (HOCl) and methods of manufacture thereof. In certain aspects, the invention provides air-free compositions of HOCl. In other aspects, the invention provides methods of making HOCl that involve mixing together in water in an air-free environment, a compound that generates a proton (H+) in water and a compound that generates a hypochlorite anion (OCl?) in water to thereby produce air-free hypochlorous acid.
