Showing papers on "Iodide published in 1974"
TL;DR: In this paper, an improved high-yield synthesis of trimethylphosphine from the reaction of triphenylphosphite with methylmagnesium iodide is described, which has been extended to prepare triethyl-, tripropyl-, and triisobutyl phosphine.
Abstract: An improved high-yield synthesis of trimethylphosphine from the reaction of triphenylphosphite with methylmagnesium iodide is described. This route has been extended to prepare triethyl-, tripropyl-, and triisobutylphosphine.
145 citations
TL;DR: In this paper, the sorption of iodide by several soil component materials was examined over a range of pH values and compared with sorption by a surface soil A compost, prepared from grass roots which had been allowed to decompose for 24 weeks, showed changes in sorption, due to pH and drying, similar to those shown by the soil.
Abstract: The sorption of iodide by several soil component materials was examined over a range of pH values and compared with sorption by a surface soil A compost, prepared from grass roots which had been allowed to decompose for 24 weeks, sorbed substantial amounts of iodide from solution and showed changes in sorption, due to pH and drying, similar to those shown by the soil Freshly precipitated hydrated ferric oxide also sorbed substantial amounts of iodide from solutions of pH < 55 but the amount decreased to zero as the pH approached 7 Sorption by freshly precipitated hydrated aluminium oxide was impossible to assess at pH < 5 owing to its solubility but at pH 55 to 75 its sorption was similar to that of ferric oxide No sorption of iodide was detected by kaolinite, montmorillonite, chalk or limestone
Drying markedly reduced the capacity for iodide sorption of the compost and soil and had a smaller effect on the ferric and aluminium oxides
96 citations
TL;DR: In this paper, a new method for determining iodate and total iodate in seawater is described, where iodate is directly measured by differential pulse polarography with a precision (1σ) of 2·5%.
88 citations
TL;DR: Iodimetric titrations and pH profiles suggest that the oxidation and oxidative cleavage of tryptophan peptides during iodination proceeds via the mechanism proposed for brominating agents.
76 citations
75 citations
TL;DR: In this paper, the formation of carbon surface oxides on platinum-catalyzed carbon was examined by a linear potentiodynamic sweep technique and it was shown that the faradaic reactions associated with platinum were inhibited by the selective adsorption of iodide ions onto the platinum surface and thereby allowed the separation of the coulombic change due to the electroactive carbon species.
74 citations
TL;DR: In this article, the surface tension and its temperature derivative, dγ / dT, were measured by means of Wilhelmy slide techniques for dilute (≤ 1.5 m) aqueous solutions of NaCl, KCl, NaI, and KI.
70 citations
01 Jan 1974
TL;DR: In this article, the intracellular site of operation of the myeloperoxidase-H202-halide antibacterial system of granulocytes was determined by utilizing measurements of the fixation of iodide to trichloracetic acid (TCA) precipitates of subcellular fractions, including intact phagocytic vesicles.
Abstract: A B S T R A C T The intracellular site of operation of the myeloperoxidase-H202-halide antibacterial system of granulocytes has been determined by utilizing measurements of the fixation of iodide to trichloracetic acid (TCA) precipitates of subcellular fractions, including intact phagocytic vesicles. Na'I was added to suspensions of guinea pig granulocytes in Krebs-Ringer phosphate buffer, and they were then permitted to phagocytize different particles. Phagocytic vesicles were formed by allowing cells to ingest a paraffin oil emulsion (POE) and collected by flotation on sucrose after homogenization. Measurement of 'I bound to TCA precipitates of the different fractions and the homogenates disclosed that the lysosome-rich fraction obtained by centrifugation from control (nonphagocytizing) cells accounted for a mean 93.1% of the total cellular activity. With phagocytosis of POE, TCA-precipitable iodination increased two- to sevenfold, and the lysosomal contribution fell to a mean 36.9% of the total. The appearance of activity within phagocytic vesicles accounted for almost the entire increase seen with phagocytosis (a mean 75.7%), and iodide was bound within these structures with high specific activity. More iodide was taken up by cells than fixed, regardless of iodide
70 citations
TL;DR: Iodate solubility in both 0.01 M CaCl2 and 1.0 M NK4 acetate (pH 4.8) was determined after various periods of incubation as mentioned in this paper.
Abstract: Summary
Iodine in each of the forms iodide, elemental iodine, and iodate was added, at a rate of 5 mg/kg to a sandy loam and to mixtures of the soil with composted grass roots, chalk and sesquixoides, and its solubility determined after various periods of incubation.
With iodide, solubility in both 0.01 M CaCl2 and 1.0 M NK4 acetate (pH 4.8) declined rapidly over the period o to 3 days and subsequently reached approximate equilibrium levels of 2.8 per cent solubility in CaCl2 and 7.8 per cent in NH4 acetate, these values being the means of samples incubated for 48, 103, and 160 days. The partial (5 per cent) replacement of the soil by composted grass roots had no appreciable effect on the solubility of added iodide, while chalk, incorporated at a rate of 5 per cent, depressed the solubility of iodide in CaCl2 to 1.8 per cent but caused a slight increase in solubility in NH4 acetate. The incorporation of 2 per cent hydrated ferric oxide or of 2 per cent hydrated aluminium oxide reduced the solubility of iodide in CaCl2 to 0.1 and 0.3 per cent, and in NH4, acetate to 3.8 and 5.7 per cent respectively. Elemental iodine was similar to iodide in its solubility in the two extractants and in its response to the various soil treatments. Iodate, however, differed considerably from the other two forms of iodine. With soil alone, and with the soil/chalk mixture, its decline in solubility with increasing incubation time was relatively slow, although after 160 days its solubility was similar to that of iodide and elemental iodine. The incorporation of composted grass roots caused a rapid reduction in iodate solubility, suggesting that the organic matter accelerated the reduction of iodate to elemental iodine or iodide. With the treatments involving the incorporation of ferric and aluminium oxides, there appeared to be considerable sorption of iodate during the 16 h extraction period and the effects of these materials on iodate solubility during incubation were therefore difficult to assess.
56 citations
TL;DR: The thermal stability of the Grignard reagent and the products of the thermal decomposition have been estimated in diethyl ether and tetrahydrofuran as mentioned in this paper.
55 citations
TL;DR: A new and convenient esterification procedure for both synthetic and analytical purposes has been developed that can be substituted for more complex and lengthier reactions, such as transesterifications, which are often employed.
TL;DR: The mechanism of energy conservation associated with Photosystem II may be only operative when the removal of electrons from the donor results in release of protons (i.e. with water, hydroquinones, phenylamines, etc.).
TL;DR: In this article, the heats and entropies of gas phase association of chloride, bromide and iodide with the respective methyl halides are reported, and it is shown that the solvent is the dominant factor in determining relative halide nucleophilicities for the reactions in solution.
Abstract: The heats and entropies of gas phase association of chloride, bromide and iodide with the respective methyl halides are reported. Comparison of these results with results published for SN2 reactions in solution suggests that the solvent is the dominant factor in determining relative halide nucleophilicities for the reactions in solution.
TL;DR: In this article, the optical absorption of the vapors above neodymium iodide and cerium ionide were studied and it was shown that a stable complex molecule CsI · NdI3 is formed that increases the amount of Nd vaporized.
Abstract: The optical absorption of the vapors above neodymium iodide and cerium iodide were studied: (1) individually, (2) in combination with cesium iodide, and (3) in combination with cesium iodide and mercury between 600 and 1100°C. Changes in the spectra show that a stable complex molecule CsI · NdI3 is formed that increases the amount of Nd vaporized. A similar enhancement of the vaporization of Ce appears to occur with the cerium plus cesium iodide system, but no changes in absorption structure were found. At high mercury pressure a weak complex between Hg and CsI · NdI3 apparently forms. Vapor pressures and thermodynamic quantities have been deduced from the data.
TL;DR: In dispersed thyroid cells, iodide concentrating activity was depressed as much as 70% following preincubation with iodide (4 to 60 µM) and appears to represent an in vitro counterpart of the autoregulation of iodide transport that has been observed in rats and mice given injections of iodides.
Abstract: In dispersed thyroid cells, iodide concentrating activity was depressed as much as 70% following preincubation with iodide (4 to 60 µM). This effect of iodide appears to represent an in vitro counterpart of the autoregulation of iodide transport that has been observed in rats and mice given injections of iodide. The depression of iodide accumulation was increased in proportion to the duration of the preincubation, to the iodide concentration used, and to the magnitude of iodoprotein formation during the preincubation. It was completely abolished by methimazole present during the preincubation. The depression of iodide concentrating activity induced by iodide was attributable to decreases in the rate constant for unidirectional iodide influx without alteration in the iodide efflux process, so that at any particular concentration of iodide in the medium, the rate of iodide influx was lower in iodide pretreated cells than in the corresponding control cells. This depression of the influx process was associate...
TL;DR: Molecular iodine is shown to be unstable in seawater and at least two reduction reactions proceed simultaneously, and with higher initial molecular iodine concentrations production of iodate was observed.
TL;DR: Micelles of sodium dodecyl sulfate and cetyltrimethylam- monium bromide containing anthracene were used to char- acterize the quenching properties of pyridinium and iodide ions in a model system where the fluorophore and charge distribution are known with certainty.
Abstract: The accessibility of fluorescent groups in proteins can be determined with charged quenching agents which provide information about conformational topography and local charge distribution surrounding the fluorescent moiety. Micelles of sodium dodecyl sulfate and cetyltrimethylam- monium bromide containing anthracene were used to char- acterize the quenching properties of pyridinium and iodide ions in a model system where the fluorophore and charge distribution are known with certainty. Iodide ions were ef- fective quenchers only with positively charged cetyltrimeth- ylammonium bromide micelles. Pyridinium ions quenched anthracene fluorescence only in negatively charged sodium dodecyl sulfate micelles. The quenching constants for pyri- dinium chloride in ethanol and sodium dodecyl sulfate micelles were 42 and 520 M-~, respectively. For potassium iodide the corresponding values in ethanol and cetyltri-
TL;DR: In this paper, a microwave-excited (2450 MHz) electrodeless arsenic discharge lamp, a solar-blind photomultiplier, and a lock-in amplifier are used.
TL;DR: In this paper, the halogenosulphinate ion SO2X was modified by CH 2CH2CH2NH3X where X is chlorid, bromide, or iodide adsorbs sulphur dioxide selectively to form the SO 2X; the process reverses upon warming.
Abstract: Silica gel modified by –CH2CH2CH2NH3X where X is chlorid, bromide, or iodide adsorbs sulphur dioxide selectively to form the halogenosulphinate ion SO2X–; the process reverses upon warming.
TL;DR: In this article, the standard enthalpy change for solution of gaseous hydrogen iodide in water was found by direct solution calorimetry to be ΔH soln o (298.15K) = −(19905 ± 20) cal th mol −1.
TL;DR: In this article, the surface bonding of iodide was shown to result from a reaction of these sites with halogen intermediates formed in the aqueous phase, predominantly by reaction of OH radicals with iodide.
Abstract: At a population of 1.4 X 1012 particles of 0.234-um diameter cc-', the yield of surfacebonded halogen in 5 X 10-4 M iodide corresponds to 0.02 iodine atoms bonded to the particle surface per 100 eV of total energy absorbed. In 5 X 10-4 M iodide, the reaction rate is proportional to the surface area and depends upon the first power of the radiation intensity. The experimental results are consistent with a reaction mechanism in which radical sites are produced on the particle surface by reaction of OH and other radicals from the bulk phase. A surface bonding of iodine results from a reaction of these sites with halogen intermediates formed in the aqueous phase, predominantly by reaction of OH radicals with iodide. Energy absorbed in the particle apparently plays no major role in the reaction, and a complex dependence of the reaction upon the iodide concentration suggests that a surface adsorption of halogen intermediates plays an important role in the reaction.
TL;DR: An analytical method for determining sup 129/I in environmental milk and water samples is described, which depends on the specificity of elemental iodine separation by solvent extaction, followed by liquid scintillation counting of the lowenergy beta emissions from /sup 129/ I.
Abstract: An analytical method for determining sup 129/I in environmental milk and water samples is described. The method depends on the specificity of elemental iodine separation by solvent extaction, followed by liquid scintillation counting of the lowenergy beta emissions from /sup 129/I. Iodine, as iodide, is concentrated by sorption on an anion exchange column and eluted with NaOCl. After reduction to I/sub 2/, the iodine is extracted into CCl/sub 4/, back extracted into water, cleaned by one toluene-water extraction cycle, and finally extracted into toluene. Chemical recovery of the added carrier is determined spectrophotometrically on a small aliquot of the toluene extract. The /sup 129/I concentration is determined by liquid scintillation counting of the toluene solution. Average % recovery of iodine carrier is 74 plus or minus 2 for water 58 plus or minus 3 for raw milk, and 80 plus or minus 4 for pasteurized milk. Analytical sensitivity is 0.3 pCi /sup 129/I/l. for a 4 -- 1. sample. (auth)
TL;DR: A 25-yr-old woman with no clinical hypothyroidism had a goiter since childhood, and the thyroid tissue obtained at thyroidectomy contained a high concentration of thyroid peroxidase, indicating a partial iodine organification defect.
Abstract: A 25-yr-old woman with no clinical hypothyroidism had a goiter since childhood. Her mother and first cousin also had goiters. 33% of the thyroidal iodine was released by perchlorate indicating a partial iodine organification defect. Plasma thyroxine as well as the concentration inorganic iodide were very low. Thyroid iodine uptake was very high. The thyroid tissue obtained at thyroidectomy contained a high concentration of thyroid peroxidase (I2 formation from I−, when tested after solubilization of the enzyme by trypsin and digitonin treatment of the particulate material. 1. The enzymatic activity behaved on DEAE column chromatography exactly as those of hog or sheep. Its sedimentation coefficient (5.5 S) and molecular weight (97,000) were almost identical to those of the hog enzyme (5.2 S and 103,000). 2. Both hog and goiter enzyme catalyzed iodide peroxidation (I− → I2) and gaiacol oxidation to tetragaiacol. The km (iodide) values (3 × 10−3m) were almost identical for the two enzymes; km (gaia...
TL;DR: In this article, a model based on the ion-ion interactions rather than ion-electrode interactions was proposed to explain the results of aqueous tetramethylammonium fluoride, chloride, bromide and iodide solutions.
TL;DR: In this article, the PMR spectra of quaternary pyrimidinium ion demethylates were measured and it was shown that the demethylation reaction occurs via an Addition-Nucleophile-Ring-Opening-Ring Closure mechanism.
Abstract: On treatment with liquid ammonia at −33°C, the quaternary pyrimidinium salts, i.e. 1-methylpyrimidinium methyl sulfate (4a), 1,2-dimethylpyrimidinium iodide (4b), 1,4,6-trimethyl-pyrimidinium iodide (4c) and 1,2,4,6-tetramethylpyrimidinium iodide (4d) demethylate yielding pyrimidine, 2-methyl-, 4,6-dimethyl- and 2,4,6-trimethylpyrimidine, respectively. It was observed that under these conditions 1-methyl-[1.3-15N]-pyrimidinium methyl sulfate yields [1-15N]-pyrimidine. By measuring the PMR spectra of above-mentioned pyrimidinium salts in liquid ammonia it is shown that these salts undergo covalent amination on the 1,6-azomethine bond. These results indicate that the demethylation reaction occurs via an Addition-Nucleophile-Ring-Opening-Ring Closure mechanism.
TL;DR: Wittig condensation of indole-1-(p-toluenesulfonyl)-3-methyltriphenylphosphonium iodide (8) with aromatic and heterocyclic aldehydes gives good yields of the 3-(2-aryl)-vinylindole derivatives 9a-g...
Abstract: Wittig condensation of indole-1-(p-toluenesulfonyl)-3-methyltriphenylphosphonium iodide (8) with aromatic and heterocyclic aldehydes gives good yields of the 3-(2-aryl)-vinylindole derivatives 9a–g...
TL;DR: In this article, the 590 nm absorption band is assigned to the I radical anion which presumably could be formed by the equilibrium reaction: I + I 3 − ⇌ I.