Sodium Bromate Research Articles

Synthetic Methods and Reactions; 951. Ceric Ammonium Nitrate-Catalyzed Oxidative Cleavage of Alkyl and Silyl Ethers with Sodium Bromate

Synthetic Methods and Reactions; 95¹. Ceric Ammonium Nitrate-Catalyzed Oxidative Cleavage of Alkyl and Silyl Ethers with Sodium Bromate

Electronmicroscopic Findings of the Stria Vascularis after Administration of Sodium Bromate in Guinea Pigs

Electronmicroscopic Findings of the Stria Vascularis after Administration of Sodium Bromate in Guinea Pigs

Period of homogeneous oscillations in the ferroin-catalyzed Zhabotinskii system

This work is primarily an experimental investigation of the ferroin-catalyzed Zhabotinskii system [malonic acid (MA), sulfuric acid, sodium bromate, traces of bromide ions, and ferroin]. We measure the transmittance as a function of time at 546 nm. The emphasis is placed on the properties of the period of homogeneous oscillations. It is found that T depends on the initial concentrations of reactants: T (s) = C [BrO−3]−1.60 [H2SO4]−2.70 [MA]−0.270 s (mol dm−3)4.57. The period is not perfectly constant. We investigate the conditions which favor irregularities: Low concentrations of BrO−3, H2SO4, or MA; high concentrations of catalyst or reaction products. The irregularities in the period of homogeneous oscillations are of direct interest for our understanding of the formation of waves in the distributed system. Also, we find bifurcations in which a transition from steady-state to full-blown oscillations is observed. Such bifurcations may be due to an unstable limit cycle or to a saddle-node transition. We discuss the saddle-node case in terms of the Bautin model. Finally, two steady states are observed. One of them has not been reported previously: In this state, the catalyst is mostly oxidized (blue). The oxidized steady state occurs at low [MA]0. Under the same conditions of low [MA]0, the distributed system exhibits both oxidizing (blue) and reducing (red) waves. This interesting new observation shows how much the ferroin-catalyzed Zhabotinskii system is still underinvestigated.

Thermoluminescence and Optical Absorption of X-Ray Irradiated NaBrO32

Single crystals of sodium bromate grown by slow cooling of a saturated aqueous solution, are subjected to X-irradiation at 77 K. Thermoluminescence glow curves of the irradiated crystals recorded in the temperature range from 77 to 400 K show four glow peaks. Optical absorption spectra of the damaged crystals also are recorded as a function of radiation dose and at different stages of thermal annealing between 77 and 400 K. On the basis of the results of optical measurements, the glow peaks at 115, 159, 229, and 300 K are identified as due to O2− in the vicinity of BrO3, BrO3 itself, O2− in the neighbourhood of BrO2, and BrO2 itself, respectively. The variations in the thermoluminescence spectrum with the dose of irradiation are consistent with the assignment of secondorder kinetics for all four glow peaks. The trapping parameters also are determined for these centers.

Die Struktur der durch Halogenierung von Furfural in Wasser gebildeten Oxydationsprodukte

The Structures of the Oxidation Products formed by Hologenation of Furfural in WaterThe oxidation products formed on halogenating furfural in water are cis/trans‐2,5‐dihydroxy‐2‐(dihydroxymethyl)‐2,5‐dihydrofuran (5) and cis/trans‐2,6‐dihydroxy‐2 H‐pyran‐3 (6H)‐one (6) as shown by 1H‐ and 13C‐NMR.‐spectroscopy. A new, simple high‐yield preparation of 5‐ and 6‐ solutions is described, in which sodium bromate is used as the oxidizing agent.

X-ray determination of lattice parameters, thermal expansion and defect formation energy of sodium bromate

X-ray determination of lattice parameters, thermal expansion and defect formation energy of sodium bromate

Raman spectra of halate ions as solid solutions in sodium chlorate and bromate lattices

AbstractThe fundamental vibrational modes of the halate ions as solid solutions in NaClO3 and NaBrO3 lattices have been studied by laser Raman spectroscopy, both at room and at low (80 K) temperature. The four predicted modes have all been observed and assigned for each halate ion. The local symmetry of the doping ions in the host lattices at both temperatures is discussed.

Remeasurement of optically active NaClO3 and NaBrO3

Remeasurement of optically active NaClO₃ and NaBrO₃

The x-ray anomalous dispersion and optical rotation in the crystalline solid solution NaClO3: NaBrO3

Sodium chlorate and sodium bromate crystals of thes ame structural configuration have opposite senses of optical rotation. It is also known that these halates exhibit continuous miscibility in solid solution. In the present work, the conjecture of Bijvoet that in the solid solution of these halates, the crystalline configuration would continue itself, has been directly verified by two approaches: (i) by optical rotation measurements on single crystals which show an annulling trend in proportion with composition and (ii) by measuremerts of Bijvoet inequality for several reflections from a single crystal (rich in chlorate) which shows an agreeable trend with the calculated values for chlorate.

Magnetic Gyration of Mixed Crystals of Sodium Chlorate and Sodium Bromate

The magneto-optical rotary dispersion exhibited by mixed crystals of sodium chlorate and sodium bromate has been measured. The measured data could not be accounted on the basis of usual additive laws. Assuming that in a solid solution a cation is surrounded by dissimilar anions, an expression for the Verdet constant of the mixed crystal has been arrived at. This formula explains the observed data well.

Viscosity of Solutions of Sodium Bromate and Potassium Iodate at 30°, 35° and 40° ; Calcium Chloride at 35°, 40° and 45° and Barium Chloride at 30°, 40° and 45°

Viscosity of Solutions of Sodium Bromate and Potassium Iodate at 30°, 35° and 40° ; Calcium Chloride at 35°, 40° and 45° and Barium Chloride at 30°, 40° and 45°

Optical rotation of solid solutions of sodium chlorate and sodium bromate

The optical rotary dispersion (ORD) data for a mixed crystal of sodium chlorate and sodium bromate have been analysed. It is found that the ORD exhibited by these solid solutions cannot be explained using Vegard's law of additivity. Based on the model proposed by Wasastjerna, a special form of additivity of polarisability is assumed in which the asymmetric distribution of the anions around the cation is considered. A formula has been proposed for the additivity of optical rotation in solid solutions and this is found to fit the data for optical rotation in mixed crystals of NaClO 3-NaBrO 3 of different compositions.

Optical rotation of solid solutions of sodium chlorate and sodium bromate: V. Sivaramakrishnan and K.A. Arunkumar, Department of Physics, Indian Institute of Technology, Madras 600 036, India

A simple unification of various relations for the temperature dependence of interatomic separation is presented. It is found that the relations reported by the earlier workers as new are contained in a simple thermodynamic relation. Some other relations based on different physical origins are also included in the study and compared with the thermodynamic relation. The results are reported for ten crystals, viz. KF, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, MgO and CaO. A good agreement between unified relation and experiment demonstrates the superiority of the simple theory based on the thermodynamic analysis.

A note on the elastic constants of sodium bromate from 350 K to 77 K

The elastic constantsC 11,C 12 andC 44 of sodium bromate single crystals have been evaluated using 10 MHz ultrasonic pulse echo superposition technique. The values areC 11=5.578,C 12=1.075,C 44=1.510 (×1010 N/m2) at 290 K and 6.35, 1.98 and 1.65 (×1010 N/m2) at 77 K. The present room temperature values agree closely with the recent values of Gluyaset al. but the other earlier measurements show some scatter. A comparison between the elastic constants of sodium bromate and sodium chlorate is also made.

The elastic constants of isomorphous sodium bromate and sodium chlorate from 77 to 350 K

The elastic constants of NaBrO 3 and NaClO 3 are evaluated from ultrasonic velocity measurements using pulse superposition techniques. The values of C 11, C 12 and C 44 for NaBrO 3 at 298°K are 5.57 8, 1.70 5, 1.51 0 (x 10 10 N/m 2) and for NaClO 3 the values are 4.89 7, 1.38 9, 1.17 4. The values at 77°K are respectively 6.35, 1.98 and 1.65 for NaBrO 3 and 6.15, 2.16 and 1.32 for NaClO 3.

The elastic constants of sodium bromate from 150 to 300K

The elastic constants c11,c12 and c44 of sodium bromate have been calculated from measurements of the velocities of 10 MHz ultrasonic waves transmitted through a single crystal specimen in the following directions: longitudinal waves transmitted in the (100) and (111) directions, and shear waves transmitted in the (111) direction. The measurements have been made over the range 150-300K. The results have been extrapolated to 0K to permit the calculation of the Debye characteristic temperature which at 0K was found to be 238K.

Precipitation of lead as lead sulphate by destructive oxidation of EDTA

Gravimetric determination of lead (5–100 mg) by homogeneous precipitation of lead sulphate from a solution containing lead(II), EDTA and sulphate by destructive oxidation of EDTA with hydrogen peroxide or sodium bromate is described. Aluminium(III), iron(III), zinc(II), manganese(II), copper(II), nickel(II), tin(II) and antimony(III) do not interfere in the method. The method can successfully be applied to the analysis of type metal.

Indirect electronic transitions in alkali halate crystals-II (sodium bromate and iodate) crystals

In the case of NaClO 3 and KClO 3 crystals, analysis of the long wavelength tail of their fundamental absorption revealed the active participation of the internal vibrations of the chlorate ion (Part I). In order to test the validity of the above interpretation the absorption spectra of two more halates with different anions namely sodium bromate and sodium iodate are analysed in a manner similar to that given in Part I. It is found that the principle internal vibrations of bromate and iodate ions are involved in the indirect transitions. The variation of indirect band gap with temperature is found to be −2·5 × 10 −4 eV/K and −2·9 × 10 −4 eV/K for sodium bromate and sodium iodate respectively.

Light Scattering from Polaritons in NaBrO3 and NaClO3

Light Scattering from Polaritons in NaBrO₃ and NaClO₃

Kinetics of defect and radiolytic product formation in single crystal sodium bromate determined from color-center measurements

Kinetics of defect and radiolytic product formation in single crystal sodium bromate determined from color-center measurements