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Nucleation of neutral iodine particles has recently been found to involve both iodic acid (HIO3) and iodous acid (HIO2). However, the precise role of HIO2in iodine oxoacid nucleation remains unclear. Herein, we probe such a role by investigating the cluster formation mechanisms and kinetics of (HIO3)m(HIO2)n(m = 0-4, n = 0-4) clusters with quantum chemical calculations and atmospheric cluster dynamics modeling. When compared with HIO3, we find that HIO2binds more strongly with HIO3and also more strongly with HIO2. After accounting for ambient vapor concentrations, the fastest nucleation rate is predicted for mixed HIO3-HIO2clusters rather than for pure HIO3or HIO2ones. Our calculations reveal that the strong binding results from HIO2exhibiting a base behavior (accepting a proton from HIO3) and forming stronger halogen bonds. Moreover, the binding energies of (HIO3)m(HIO2)nclusters show a far more tolerant choice of growth paths when compared with the strict stoichiometry required for sulfuric acid-base nucleation. Our predicted cluster formation rates and dimer concentrations are acceptably consistent with those measured by the Cosmic Leaving Outdoor Droplets (CLOUD) experiment. This study suggests that HIO2could facilitate the nucleation of other acids beyond HIO3in regions where base vapors such as ammonia or amines are scarce. publishedVersion

In this study, a low temperature hydro iodic acid (HI) vapor treatment of the self-assembled graphene films has been developed, and the electrical, optical, structural and morphological properties were investigated by four point probe, UV-Visible spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). Mono-, doubleand triple-layer of graphene flakes were deposited on glass substrates by using the Double Self-Assembly (DSA) process. The self-assembled graphene films were treated with HI vapors at 40 degrees C for different time intervals between 1 and 24 h. In addition, graphene deposition and HI-vapor treatment (at 40 degrees C for 1 h) was enforced three times to the same substrate. The optical transparency values of the self-assembled mono- (MGFs), double- (DGFs) and triple-layer graphene flakes (TGFs) were measured as 91, 85 and 80%, respectively (values at 550 nm). Due to the HI-vapor treatment, the sheet resistance of MGFs significantly reduced from 1.1 x 10(7) Omega omega square(-1) to 2.9 x 10(4) omega square(-1), the transparency of the graphene films slightly reduced by 2-5%, the I-D/I-G ratio of the DGFs decreased from 1.01 to 0.81, while the I-2D/I-G ratio increased from 0.43 to 0.48 in the Raman spectrum. Thanks to its impressive reducing effect on sheet resistance, HI-vapor treatment can be a suitable method to improve the conductivity of low-cost large area graphene films. Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK)

Open Access Article. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/., Emitted from the oceans, iodine-bearing molecules are ubiquitous in the atmosphere and a source of new atmospheric aerosol particles of potentially global significance. However, its inclusion in atmospheric models is hindered by a lack of understanding of the first steps of the photochemical gas-to-particle conversion mechanism. Our laboratory results show that under a high humidity and low HOx regime, the recently proposed nucleating molecule (iodic acid, HOIO2) does not form rapidly enough, and gas-to-particle conversion proceeds by clustering of iodine oxides (IxOy), albeit at slower rates than under dryer conditions. Moreover, we show experimentally that gas-phase HOIO2 is not necessary for the formation of HOIO2-containing particles. These insights help to explain new particle formation in the relatively dry polar regions and, more generally, provide for the first time a thermochemically feasible molecular mechanism from ocean iodine emissions to atmospheric particles that is currently missing in model calculations of aerosol radiative forcing. © 2020, The Author(s)., This study has received funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation programme (Project “ERC-2016-COG 726349 CLIMAHAL”). J.C.G.M. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), the Ramon y Cajal Program (RYC-2016-19570) and the National I + D + i Program (RTI2018-095330-B-100). We thank the Holland Computing Center of the University of Nebraska—Lincoln for providing computing resources.

Iodine is enriched in marine aerosols, particularly in coastal mid-latitude atmospheric environments, where it initiates the formation of new aerosol particles with iodic acid (HIO3) composition. However, particle formation in polluted and semipolluted locations is inhibited when the iodine monoxide radical (IO) is intercepted by NO2 to form the iodine nitrate (IONO2). The primary fate of IONO2 is believed to be, besides photolysis, uptake by aerosol surfaces, leading to particulate iodine activation. Herein we have performed Born-Oppenheimer molecular dynamics (BOMD) simulations and gas-phase quantum chemical calculations to study the iodine acids-iodine nitrate [HIOx (x = 2 and 3)-IONO2] dynamics at the air-water interface modeled by a water droplet of 191 water molecules. The results indicate that IONO2 does not react directly with these iodine acids, but forms an unusual kind of interaction with them within a few picoseconds, which is characterized as halogen bonding. The halogen bond-driven HIO3-IONO2 complex at the air-water interface undergoes deprotonation and exists as IO3--IONO2 anion, whereas the HIO2-IONO2 complex does not exhibit any proton loss to the interfacial water molecules. The gas-phase quantum chemical calculations suggest that the HIO3-IONO2 and HIO2-IONO2 complexes have appreciable stabilization energies, which are significantly enhanced upon deprotonation of iodine acids, indicating that these halogen bonds are fairly stable. These IONO2-induced halogen bonds explain the rapid loss of IONO2 to background aerosol. Moreover, they appear to work against iodide formation. Thus, they may play an important role in enhancing the amount of atmospherically nonrecyclable iodine (iodate) in marine aerosol. © 2020 American Chemical Society, This work was supported by the University of Nebraska Holland Computing Center.

11 pags., 4 figs.-- Correction: https://www.nature.com/articles/s41467-020-19533-y, In the central Arctic Ocean the formation of clouds and their properties are sensitive to the availability of cloud condensation nuclei (CCN). The vapors responsible for new particle formation (NPF), potentially leading to CCN, have remained unidentified since the first aerosol measurements in 1991. Here, we report that all the observed NPF events from the Arctic Ocean 2018 expedition are driven by iodic acid with little contribution from sulfuric acid. Iodic acid largely explains the growth of ultrafine particles (UFP) in most events. The iodic acid concentration increases significantly from summer towards autumn, possibly linked to the ocean freeze-up and a seasonal rise in ozone. This leads to a one order of magnitude higher UFP concentration in autumn. Measurements of cloud residuals suggest that particles smaller than 30 nm in diameter can activate as CCN. Therefore, iodine NPF has the potential to influence cloud properties over the Arctic Ocean., The Swedish Polar Research Secretariat (SPRS) provided access to the I/B Oden and logistical support in collaboration with the U.S. National Science Foundation. This work was supported by the Swiss National Science Foundation (grant no. 200021_169090), the Swiss Polar Institute, the BNP Paribas Swiss Foundation (Polar Access Fund 2018), the Knut-and Alice-Wallenberg Foundation within the ACAS project (Arctic Climate Across Scales, project no. 2016.0024), the Bolin Centre for Climate Research (RA2), the Swedish Research Council (project nos. 2018-05045 and 2016-05100) and by the Natural Environment Research Council (grant no. NE/R009686/1). J.S. holds the Ingvar Kamprad Chair, sponsored by Ferring Pharmaceuticals. A.S.-L. acknowledges the funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation program (Project ‘ERC-2016-COG 726349 CLIMAHAL’). Funding of the expedition AO2018 was provided to Caroline Leck by the NSF and SPRS’s Cost sharing Understanding Arctic Ocean 2018 Reg. no. 2018-113, and by the Swedish Research Council projects nos. 824-2013-222 and 2016-03518. We are grateful to Xu-Cheng He (University of Helsinki, Finland) for the insightful discussions about iodine NPF and for helping with the calibration of the nitrate CIMS. We would like to thank Michael Wheeler and Richard Leaitch (Environment and Climate Change Canada) for lending the CVI inlet and the technical support and Silvia Henning (TROPOS, Germany) for lending and calibrating the cloud condensation nuclei counter. We also thank Heini Wernli (ETH Zürich, Switzerland) for calculating the air mass backtrajectories, Barbara Brooks (National Centre for Atmospheric Science, U.K.) for processing the FSSP data and John Prytherch (Stockholm University, Sweden) for processing temperature and wind speed data. We acknowledge the CABM network for providing the iodine measurement at Alert and CFS Alert for maintaining infrastructure for Alert location.

An oxidation system in which iodic acid (HIO3) is used as an oxidant in the presence of N-hydroxyphthalimide (NHPI) permitted the selective hydroxylation of tertiary C-H bonds and the lactonization of carboxylic acids containing a tertiary carbon center. These reactions are operationally simple and proceed under metal-free conditions using commercially available reagents, thus offering an ideal tool for the efficient oxidation of C-H bonds at tertiary carbon centers.

The effect of processing liquids on particle surface hydration and subsequent reactivity of mixtures containing aluminum (Al) with different oxidizing agents was investigated. Recently, polar processing liquids were shown to significantly increase the surface hydration layer on Al particles and effect the reactivity of Al combined with polytetrafluoroethylene (PTFE). Processing mixtures of Al and PTFE using hexane (e.g., a non-polar liquid) limited surface hydration and produced significantly lower flame speeds than the same mixture processed in isopropanol (e.g., a polar liquid). Increased surface hydroxyl concentration was linked to higher exothermic behavior within a pre-ignition reaction (PIR) which may contribute to higher overall flame speed. This study extends the previous analysis toward assessing the influence of processing liquid on reactivity of aluminum with other oxidizing agents, specifically CuO, MoO 3 and I 2 O 5 . Results from DSC analysis show no PIR kinetics associated with Al and CuO or MoO 3 , and Al+ CuO showed no difference in reactivity as a function of processing liquid. But, MoO 3 FTIR shows modified surface structures after treatment in a polar solvent. Correspondingly, Al + MoO 3 processed in polar solvent exhibited increased flame speed by 19% when compared to Al + MoO 3 processed in a non-polar liquid. For Al + I 2 O 5 , water in polar processing liquids produces various hydrated states of iodic acid (i.e., HIO 3 and HI 3 O 8 ). Changing the hydration state of I 2 O 5 significantly impacts reactivity. Results from this study confirm that carrier fluid used to process Al with metal oxides can also alter the surface structure of the metal oxide, thereby promoting greater reactivity with Al. A polar carrier fluid not only modifies the surface of Al but also hydration sensitive metal oxides such as MoO 3 and correspondingly promotes greater reactivity.

Iodic acids are widely studied in atmospheric and biological applications but their inherent hydrophilic properties introduce complexities that affect their functionality and reactivity. We have shown that iodic acid (HIO3) dehydrates directly into iodine pentoxide (I2O5) in contradiction to the generally accepted multi-step dehydration mechanism where HIO3 dehydrates into HI3O8 first, then dehydrates into I2O5. The generally accepted mechanism is used to determine the concentration of iodic acid by TGA and is only valid for special conditions. The revised mechanism allows for the determination of concentrations of iodic acids under all conditions, and the more specific conditions where the accepted mechanism is valid are shown. The determination of concentration of iodic acid with the revised dehydration mechanism is dependent on assumptions of residual water and initial concentration of HI3O8. The validity of these assumptions is established by studying the absorption and hydration behavior of I2O5 from atmospheric water. These results will have an impact on the handling and use of iodine.

A crystalline aluminum iodate acid salt has been synthesized from aluminum particles dissolved in iodic acid solution. The precipitate from solution is aluminum iodate hexahydrate [Al(H2O)6](IO3)3(HIO3)2, as confirmed by X-ray diffraction (XRD) analysis. The method of synthesis first dissolves iodine oxide in water, creating an IO3− solution with pH

In coastal regions, intense bursts of particles are frequently observed with high concentrations of iodine species, especially iodic acid (IA). However, the nucleation mechanisms of IA, especially in polluted environments with high concentrations of sulfuric acid (SA) and ammonia (A), remain to be fully established. By quantum chemical calculations and atmospheric cluster dynamics code (ACDC) simulations, the self-nucleation of IA in clean coastal regions and that influenced by SA and A in polluted coastal regions are investigated. The results indicate that IA can form stable clusters stabilized by halogen bonds and hydrogen bonds through sequential addition of IA, and the self-nucleation of IA can instantly produce large amounts of stable clusters when the concentration of IA is high during low tide, which is consistent with the observation that intense particle bursts were linked to high concentrations of IA in clean coastal regions. Besides, SA and A can stabilize IA clusters by the formation of more halogen bonds and hydrogen bonds as well as proton transfers, and the binary nucleation of IA-SA/A rather than the self-nucleation of IA appears to be the dominant pathways in polluted coastal regions, especially in winter. These new insights are helpful to understand the mechanisms of new particle formation induced by IA in clean and polluted coastal regions.

The formation of oriented nanostructures of iodic acid (HIO3) on track-etched membranes has been studied. The study has shown that the method of forced filtration of supersaturated crystallization solutions through track membrane pores can be used to grow needlelike faceted microcrystals that have the cross size and preferential growth direction corresponding to those of the pores.

Alfred Ditte (1843–1908), a student of Henri Sainte-Claire Deville, carried on a large number of important researches in the areas of mineralogy, chemistry, and thermodynamics, in particular, vanadium and its compounds, properties of aluminum, alumina, and aluminates, the Leclanché cell, dissociation mechanism, and iodic acid and iodates.

A facile and efficient way of generating oxygen vacancies in visible light activated one-dimensional iodine doped TiO2 photocatalysts was first reported in this work. A two-step hydrothermal synthesis was used to synthesize TiO2 nanomaterials modified by iodic acid (HIO3) as a dopant. Detailed analysis was conducted to illustrate the intrinsic doping/reaction mechanisms of iodic acid in the modification of the TiO2 matrix. The phase and structure evolution were deduced from X-ray diffraction (XRD), Raman, and scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) was conducted to analyze the generation of oxygen vacancies and the formation of I–O–Ti bonds in the TiO2 lattice. Multi-valences of iodine, due to the reduction of iodic acid, facilitated the generation of oxygen vacancies and 3d state Ti3+ species in the TiO2 lattice. The visible light absorption and enhanced photocatalytic activity of the TiO2 nanomaterials were attributed to existing oxygen vacancies, iodine multi-valences in I–O–Ti bonds, and 3d state Ti3+ sites in the TiO2 lattice. The photocatalytic degradation efficiency under visible light (λ > 400 nm) followed a pseudo first-order kinetic model. Rutile nanowires using a two-step synthesis method produced the highest methylene blue (10 mg L−1) degradation rate constant, Kap, of 7.92 × 10−3 min−1 compared to other synthesized nanomaterials. The Kap value obtained was an order of magnitude greater than commercial P25 (3.87 × 10−4 min−1) and pristine TiO2 nanowires (4.18 × 10−4 min−1). The iodine doped TiO2 photocatalysts can be used in TiO2/light irradiation advanced oxidation processes (AOPs) in water treatment using sunlight or a visible light source, rather than an ultraviolet irradiation source.

The Ritter-type amination of a tertiary C–H bond using iodic acid (HIO3) as an oxidant, in the presence of N-hydroxyphthalimide (NHPI) is reported. This operationally simple method is conducted under metal-free conditions, is scalable, and efficiently provides valuable α-tertiary amine derivatives.

Iodine doped titanium dioxide has been successfully prepared by simple hydrolysis of tetrabutyl titanate in the presence of iodic acid. The adopted method allowed for the production of spherical iodine doped titaniun dioxide nanoparticles with varied amount of iodine content. Analysis by X-ray diffraction, Raman, transmission electron microscopy as well as UV–vis DRS revealed that titanium dioxide nanostructures were doped with iodine which existed in two different valence states I 5+ and I − . The iodine in the form of I 5+ is believed to have doped into the lattice whereas I − was well dispersed on the surface of TiO 2 probably as iodine adducts hence rendering it to be highly absorbing in visible light region. The I-TiO 2 exhibited improved photocatalytic activity toward degradation of acid orange 7 (AO7), methyl orange (MO) and 2,4-dichlorophenol (2,4-DCP) under visible light over the pristine TiO 2 prepared by the same method. High catalytic properties are attributed to iodine doping which led to high specific surface area, absorption in visible region as well as alleviation of charge carrier recombination. The most probable route undertaken in the degradation of AO7 is through indirect oxidation by the hydroxyl radicals.

Zirconium and iodine co-doped titanium dioxide (Zr–I–TiO 2 ) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer–Emmett–Teller method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV–vis absorption spectroscopy. The catalytic activity of the catalyst was evaluated by monitoring the photocatalytic decolorization of methyl orange under visible light irradiation. The results showed that the activities of Zr–I–TiO 2 catalysts were higher than that of TiO 2 doped with iodine alone (I–TiO 2 ), and the optimal doping concentration in the Zr–I–TiO 2 calcined at 400 °C was determined to be about 0.05 (molar ratio of Zr:Ti). In addition, the photocatalytic activity of Zr–I–TiO 2 calcined at 400 °C was found to be significantly higher than that calcined at 500 or 600 °C. Based on the physico-chemical characterization, we concluded that the role of zirconium on the I–TiO 2 surface is to increase the number of reactive sites by generating a small crystal size and large surface area. The inhibition of electron–hole pair recombination, by trapping photo-generated electrons with Zr 4+ , did not contribute markedly to the improved photocatalytic activity of Zr–I–TiO 2 .

The synthesis and crystal structure are presented for the ethylenediammonium bis iodate tetra iodic acid. An X-ray investigation has shown that this compound crystallizes in a centrosymmetric monoclinic system, space group P21/c with the lattice parameters: a = 7.2536(2) A, b = 18.5351(5) A, c = 7.5685(2) A, β = 107.937(1)°, V = 968.10(3) A3. The structure was solved from 5281 independent reflections with R 1 = 0.0229 and wR 2 = 0.0428, and refined with 156 parameters. The structure is built up of [(CH2)2(NH3)2]2+ cations connected to the one-dimensional [HIO3]n chains and to the [H2I4O12]2− clusters by a weak N–H···O hydrogen bonds. [100] view of the structure of [C2H10N2] (IO3)2·4HIO3. Hydrogen bonds are represented by broken lines.

Green, mild and efficient iodination of hydroxylated aromatic aldehydes and ketones using iodine and iodic acid in the solid-state by grinding under solvent-free conditions at room temperature. This method provides several advantages such as environmentally friendly, short reaction times, high yields, non-hazardous and simple work-up procedure.

This work focuses on the structure, morphology and photocatalytic performance of pure TiO2 and IO3--doped TiO2 nanoparticles. The photocatalytic activity IO3--doped TiO2 nanoparticles in the decomposition of monocrotophos (MCP) are illustrated and discussed in comparison with standard Degussa P-25. Furthermore, IO3--doped TiO2 showed high relative photonic efficiency compared with some of the commercial photocatalysts. The obtained results show a significant dependence of the degradation performance on IO3--doped TiO2 nanoparticles’s structural, morphological and composition properties. In particular, smaller particle size, large surface area and the formation of mixed phases of TiO2 by the addition of iodic acid have a beneficial influence to enhance the photocatalytic activity of IO3--doped TiO2 nanoparticles for the degradation as well as mineralization of MCP.

Bismuth iodate was synthesized by precipitation from bismuth nitrate and iodic acid. The powder was dissolved in dilute nitric acid and single crystals were obtained by slow evaporation at 70°C. Bi(IO3)3 crystallizes in the monoclinic system, space group P21/n (N° 14), a = 8.8882(2) A, b = 5.9445(2) A, c = 15.2445(5) A, β = 97.064(1) A. BiO9 polyhedra are edge-connected forming chains parallel to the b axis; these chains are linked through (IO3) groups forming layers parallel to (101). The 3D framework is designed by linking these layers through long I–O bonds. DSC analysis shows a remarkable thermal stability.

The mechanism of the hypercoordination of the iodine atom and its role in the crystal packing of iodic acid were examined within the topological analysis of the experimental electron density function.

A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions.

The structure of the solud solution Li1-xHxIO3 (x = 0.33) is determined at room temperature by X-ray single crystal and neutron powder diffraction. The space group is found to be P63 like α-LiIO3. Hydrogen atoms are in general positions with the occupation factor 0.33 and form weak bonds with neighbouring oxygens. The structure is briefly compared with that of α-LiIO3.

Soret coefficients of aqueous phosphoric acid and aqueous iodic acid are determined conductimetrically at 25 °C. As the molality of phosphoric acid drops from 0.05 toward 0.00 mol kg−1, the enthalpy of transport jumps from 2 to 15 kJ mol−1. For iodic acid, a stronger electrolyte, the corresponding increase is smaller, from 12 to 17 kJ mol−1. Equations are developed for the enthalpy of transport of 1:1 weak electrolytes. The equations are used to evaluate the reactive enthalpy of transport and the intrinsic enthalpies of transport of the ionized and molecular forms of phosphoric and iodic acids. Equating the enthalpies of transport of the acid molecules and the acid anions provides estimates of single-ion enthalpies of transport. Thermal diffusion measurements are reported for potassium dihydrogen phosphate and potassium iodate to help interpret the results. Keywords: thermal diffusion, enthalpy of transport, Soret coefficients, weak electrolytes, phosphoric acid, iodic acid.

Benzoins are rapidly oxidised to benzils in high yields by iodic acid supported on alumina under solvent-free conditions and microwave irradiation

A new reagent system, a combination of iodic acid and sodium nitrite has been investigated for oxidative coupling of N,N-disubstituted anilines. A facile para-selective coupling occurs to give benz...

Crystals of commercial iodic( V) acid, HIO3, were investigated using single-crystal and powder X-ray diffraction. The crystals turned out to be HI3O8 or (HIO3I2O5)-I-. [iodic acid-diiodine pentaoxi ...

The paper reports on the preparation and photocatalytic activity of thin films of iodine-doped ZnO nanoflowers deposited on glass substrate using a simple growth process based on hydrothermal synthesis. Addition of iodic acid (5-20 vol%) in the reaction mixture allows the introduction of iodine ions in the form of I− or IO3− in the ZnO lattice, as suggested by X-ray photoelectron spectroscopy. Doping ZnO nanostructured films with iodine did not impact their morphology, while it has a significant influence on their optical properties. Indeed, the nanostructured ZnO films, prepared in the presence of iodic acid, display a large increase of the visible luminescence, which reaches a maximum at a concentration of 10 vol%. Finally, the photocatalytic activity of the ZnO nanostructured films for the photodegradation of a model pollutant, rhodamine B, was evaluated under UV and visible light irradiation. While under UV light irradiation, both undoped and iodine-doped ZnO films show a similar behavior, the photocatalytic performance of iodine-doped under visible light irradiation is significantly enhanced in comparison to that of undoped ZnO.

There have been a number of recent reports of the oxidation of phenols to quinones in good to excellent yields under exceptionally mild conditions when promoted by Montmorillonite K101-3 or silica gel.4 The oxidants are perborate,1 iodic acid,2 so-called percarbonate,3 and peroxydisulfate.4 I have been unable to reproduce these results. Table 1 summarizes the published yields for the oxidations of phenol and hydroquinone together with my findings. Reactions were carried out according the references except that analyses were done by extraction into chloroform and measurement of the absorbance at 440 nm where p-benzoquinone has e = 22.3 mol-1 L cm-1.5 The temperature was not specified for the oxidations by percarbonate and perborate; I used 25o C.

The spectra of iodine in the presence of iodide, iodic acid, and polyvinylpyrrolidone (PVP) were obtained. Large effects of PVP concentrations on the spectra were observed. Changes in iodine spectra in the presence of N-methyl-2-pyrrolidone and N, N-diethyl-propionamide in various solvents indicated charge-transfer type interaction in less polar solvents. The spectra of the aqueous iodine solution were more affected by the addition of PVP with a smaller degree of polymerization. Kinetic studies of hydrolysis of iodine in the absence and presence of PVP indicated that PVP accelerates hydrolysis of iodine except for the initial period. The possible mechanism of accelerated hydrolysis of iodine in the presence of PVP is complexation of triiodide ion with PVP and subsequent shifts in the hydrolysis equilibrium of iodine.

Three rate laws have been postulated for the Dushman reaction, 6H++5I−+IO3−=3H2O+3I2, with total reaction orders of four, five and six, at iodide ion concentrations below 10−8 M. New direct measurements of the rate and an examination of thermodynamic data for iodic acid solutions have eliminated some of the confusion. The complexity of iodic acid solutions, with and without added salt, makes it impossible to establish a single reaction order from the radioactive iodine exchange measurements. The new results are best expressed by a quasiempirical rate equation, −d[IO3−]⁄dt=8.59×104[H+]2(I−)[IO3−] mol l−1 min−1, which is closely approximated by −d[IO3−]⁄dt=γ±p4(H+)2(I−)(IO3−){k′+k″(HIO3)} mol l−1 min−1, with k′=2.83×105 mol−3 l3 min−1 and k″=6.60×106 mol−4 l4 min−1 for 25 °C. The second rate law is interpreted in terms of a reasonable mechanism that takes into account the thermodynamically established polymerization in iodic acid solutions.

(1) The iodic acid decomposition method for the determination of nitrogen in organic compounds, which has been reported already by the author, was extended to analyses of nitro and oxime compounds. (2) In a reaction vessel, a samplew as dissolved in acetone, reduced with a reducing agent to the corresponding amine, and then decomposed by heating with a mixture of iodic acid and strong phosphoric acid. The liberated nitrogen was determined by means of an azotometer. (3) After testing many reducing agents it was concluded that a mixture of iron metal powder and diluted sulfuric acid was the best. (4) For various nitro and oxime compounds satisfactory results were obtained by means of this modified method. (5) The specific gravity and the chemical composition of strong phosphoric acid prepared in the various conditions have been described complementally.

The Oxidation of iodine by ceric sulfate in sulfuric acid solution has been found to be of second-order with respect to iodine and first-order with respect to Ce(IV), by spectrophotometric measurements. CeSO4+2 was assumed to be the active species of ceric sulfate. The over-all rate constants were found to be k0=2.66x IC4 l2/M2Imin for the reaction rate, -d[I2]/dt=k0[C3 (IV)][I2]2 in 1.0 M H2SO4 and K″ = 1.12×108 I2/M2·min for the reaction rate, -d[I2]/dt=k′[CeSO42+] [I2]2.

(1) The strong phosphoric acid-iodic acid decomposition method for the determination of nitrogen in organic compounds, which was already reported, has been extended to the analysis of nitrate nitro...

The polarisation of Raman lines of nitric, iodic, sulphuric, selenic and selenious acids is investigated making use of the usual double-image prism method. All the lines of the concentrated nitric acid except one at 1538 which is attributed to the deformation oscillation of the hydroxyl group, show varying degrees of depolarisation which are less than the limiting value 6/7. The lines due to the nitrate ion possess a state of polarisation which is in agreement with the plane equilateral structure attributed to it. From the results of polarisation six lines belonging to the undissociated nitric acid molecule are identified with the known modes of oscillation of an unsymmetrical pyramidal model having a structure . The state of polarisation of the Raman lines of the H2SO4 molecule and its dissociation products, HSO4′ and SO4″ ions generally supports the assumption that all the three forms are tetrahedral and that HSO4′ ion is the most distorted of the three. Structural formulae of the three species and the mechanism of dissociation from one form to the other are discussed in relation to the degree of depolarisation of the breathing frequency. Polarisation of the Raman lines of selenic acid is analogous to those of sulphuric acid. The results of polarisation of the bands of iodic acid as well as selenious acid generally support the previous assignments of these bands to different molecular species.

A new method has been developed to permit accurate and rapid determination of oxidation values of organic compounds. The oxidation value of a compound can be readily obtained by determining the iodine produced from the reaction of the organic compound and potassium iodate in strong phosphoric acid. The iodine produced is absorbed into the sodium arsenite solution and the excess arsenite is titrated with the standard solution of iodine. The apparatus and procedures for this method have been investigated. According to the data obtained on some pure nonvolatile organic compounds, utilizing sample weights of 10 to 80 mg., it is indicated that this method is very accurate and an analysis can be accomplished as rapidly as in twenty to thirty minutes.

(1) A new wet combustion method for the determination of carbon in organic compounds has been developed. (2) A sample is decomposed by heating with a mixture of potassium iodate and strong phosphoric acid. The liberated carbon dioxide is absorbed in 0.1 N sodium hydroxide, using a spiral type absorber. After adding barium chloride solution the excess sodium hydroxide is titrated with 0.1 N hydrochloric acid, using thymol blue as indicator, in the absorber. (3) A part of the liberated iodine is absorbed into the tube filled with anhydrous sodium thiosulfate in order to avoid the absorption of the iodine in the alkali solution in the absorber. (4) Analyses for several organic compounds gave satisfactory results. Using 10 to 60 mg. of samples, the accuracy was with in ±2%. Analysis time for one sample is about fifty minutes.

A new method has been developed to permit the rapid determination of nitrogen in organic compounds. The sample is decomposed with iodic acid-strong phosphoric acid reagent in a glass reaction vessel, and the liberated nitrogen is collected in an azotometer filled with potassium hydroxide solution by the flow of pure carbon dioxide. From the volume of the nitrogen thus collected the percentage of the nitrogen in the sample can be readily determined. This method is, so to speak, the wet modification of the Dumas method. For various types of compounds containing nitrogen, ammonium salts, amine, azo-compound, pyrrol, thiazole, etc., satisfactory results were obtained by means of this method. The nitrogen in a 10 to 50 mg. sample can be determined for thirty to forty minutes with a simple and inexpensive apparatus. But volatile compounds, nitro- or nitroso-compounds, compounds having purine, pyridine, quinoline, and other complicated rings, etc., can not give good results.