Photometric Determination of Chlorine in a Gas Flow in the Presence of Ozone

A method was proposed for the determination of chlorine in a gas mixture containing ozone. The method is based on passing the mixture before absorption with a potassium iodide solution through a furnace, where the ozone is decomposed. The concentration of chlorine at the outlet of the furnace is determined photometrically.     

Neue verfahren zur jodometrischen mikrobestimmung von jodid- bzw. Bromidion

The methods described above are based on the fact, that iodide can be determined as iodate on iodometric way after oxidation with freshly prepared chlorine water and after removal of excess of free chlorine by means of potassium cyanide. However oxidation may be carried out by adding of hypobromite the excess of which can be removed by adding of phenol water.Bromide can be transformed to BrCl by means of an excess of chlorine water. BrCl reacts with potassium cyanide under formation of cyanogen bromide and chloride. The excess of free chlorine would be removed as cyanogen chlorine and chloride. The cyanogen bromide formed can be measured on the usual iodometric way.     

Chlorine Dioxide–Iodide–Methyl Acetoacetate Oscillation Reaction Investigated by UV–Vis and an Online FTIR Spectrophotometric Method

In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide–iodide ion–methyl acetoacetate reaction system, a series of experiments were done by using UV–vis and an online FTIR spectrophotometric method. The initial concentrations of methyl acetoacetate, chlorine dioxide, potassium iodide, sulfuric acid, and the pH have great influences on the oscillations observed at the wavelength 350 nm. There is a pre-oscillatory or induction period, and the amplitude and number of oscillations are dependent on the initial concentration of the reactants. Equations were obtained for the variation of the triiodide ion reaction rate with the reaction time and the initial concentrations in the oscillation stage. The oscillation reaction was accelerated by increasing the temperature. The apparent activation energies for the induction period and the oscillation period are 55.65 and 33.00 kJ·mol^?1, respectively. The intermediates were detected by the online FTIR analysis. Based upon the experimental data in this work and in the literature, a plausible reaction mechanism is proposed for the oscillation reaction.     

Synthesis of Isomeric Aminomethyl Derivatives of Furylmethanephosphonates

By chloromethylation of diethyl 2- and 3-furylmethanephosphonates 5-chloromethylfur-2(3)-ylmethanephosphonates were synthesized. The other four isomers of chloromethyl derivatives of furylmethanephosphonates were prepared by substitution of hydroxy groups in the corresponding phosphorylated furylmethanols via the reaction with thionyl chloride in the presence of pyridine. Thermal stability of these chlorides was sufficiently high, and they were involved in nucleophilic substitution of chlorine with azido group by treating with sodium azide in boiling acetonitrile in the presence of potassium iodide. No decomposition of substrates was observed. The azides obtained were reduced to amines with triphenylphosphine in ethanol.     

Kinetic determination of iodide, based on the chlorpromazine-bromate reaction

A kinetic method based on the catalytic effect of iodide on the chlorpromazine-bromate reaction is described. The reaction was followed spectrophotometrically by measuring the increase in the absorbance at 525 nm. Under optimal experimental conditions (10(-4)M chlorpromazine hydrochloride, 1.5(itM) phosphoric acid, 5 x 10(-4)M potassium bromate, 40 degrees ), iodide was determined between 5 and 70 ng/ml by the tangent method. The influence of reaction variables, the precision and accuracy of the method and the effect of foreign ions were studied. The procedure was applied to the determination of iodide in iodinated salts and in rat thyroid.     

Heterocyclic nitro compounds. 25. 1-Hydroxymethyl-3-nitro-1,2,4-triazoles and their derivatives

1-Hydroxymethyl derivatives of tetrazoles were obtained by the reaction of 1,2,4-triazole and 3-nitro-5-substituted triazoles with formaldehyde in water. The hydroxy groups were replaced by chlorine, and the hydroxymethyltriazoles were acetylated and tosylated. The chloro and tosyl groups are readily replaced by iodine by the action of potassium and ammonium iodide in acetone. See [1] for communication 24. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 251–256, February, 1980.     

固相配位化学反应——ⅩⅩⅩ.室温下铁氰化钾的固相反应

本文首次报道了铁氰化钾在室温下与碘化钾、硫化钾的固相氧化还原反应,实验发现在固相下铁氰化钾与碘化钾混合后,生成单质碘和亚铁氰化钾,而在溶液中该反应是反方向进行的.实验还发现,在固相下铁氰化钾与还原剂硼氢化钠不反应,而在溶液中,该反应却能进行.对反应机制进行了初步探讨.     

固相配位化学反应——ⅩⅩⅩ.室温下铁氰化钾的固相反应

本文首次报道了铁氰化钾在室温下与碘化钾、硫化钾的固相氧化还原反应,实验发现在固相下铁氰化钾与碘化钾混合后,生成单质碘和亚铁氰化钾,而在溶液中该反应是反方向进行的.实验还发现,在固相下铁氰化钾与还原剂硼氢化钠不反应,而在溶液中,该反应却能进行.对反应机制进行了初步探讨.     

Reactions of pentaamminechloroplatinum(IV) with iodide and sulfite ions

The reactions of pentaamminechloroplatinum(IV) with potassium iodide and sodium sulfite are studied. In the presence of an equimolar amount of the iodide, the chloride ions are completely substituted without subsequent displacement of the ammonia molecules that are in the trans position to the entering iodide ions. The reaction with sodium sulfite is accompanied by the reduction of Pt(IV) to Pt(II). The reaction kinetics of pentaamminechloroplatinum(IV) with potassium iodide at 22, 40, and 50°C are studied. The rate constants and activation energy of this reaction are calculated.     

Determination of thiourea and its organic derivatives with iodine trichloride

Thiourea and its organic derivatives and thiosemicarbazide are determined in water, methanol or glacial acetic acid medium by reaction with an excess of iodine trichloride in the presence of mercuric chloride. The reaction is complete in 15 min. The excess of iodine trichloride is evaluated by adding potassium iodide and titrating the liberated iodine with thiosulphate. A variety of organic thioureas can be determined with an average accuracy and precision of 0.2%.     

Iodometric determination of ferricyan in the presence of copper,silver, cadmium and zinc

Ferricyan can be determined in the presence of copper, silver and cadmium by addition of potassium ferrocyanide, filtration of the ferrocyanides of copper, silver and cadmium formed in this reaction, and titration of the potassium ferricyanide contained in the filtrate. In the case of silver, the ferricyan can also be determined without filtration by addition of potassium iodide and titration of the ferricyanide. In the case of zinc, potassium, ferrocyanide is added and without filtration the ferricyanide titrated.     

Polymers as reagents and catalysts. part x. Halogenations of acetophenone and 1,3-diketones with polymer-supported reagents

A crosslinked copolymer of styrene and 4-vinylpyridine (40-43% of monomer units) was reacted with hydrogen iodide to give a polymer containing pyridinium iodide residues. Reaction of this with chlorine in chloroform at 0° gave a polymer containing pyridinium tetrachloroiodate residues. In a similar manner but using methyl iodide in place of hydrogen iodide, crosslinked polymers containing N-methylpyridinium iodide and N-methylpyridinium tetrachloroiodate residues were prepared. The latter contained up to three chlorine molecules per iodine atom. Both reagents reacted with acetophenone, thus forming iodomethyl-phenyl ketone ($\text{4}$) and chloromethyl-phenyl ketone ($\text{5}$), the ratios depending on the reagent used and the reaction time. Chlorinations of 5,5-dimethyl cyclohexane-l,3-dione and indane-1,3-dione with polymer-supported reagent ($\text{2}$) resulted in the formation of geminal dichlorides in high yields.     

“离子键”课堂演示实验的改进——碘化钠的简易制备

从教材中钠和氯气反应的演示实验出发,设计独特的实验装置,在实验室里完成了碘化钠的制备。避免了氯气的危害,也满足教学的需要。从热力学角度进行相关计算,证明本实验的可行性。     

Electroconductivity of potassium iodide solutions in the system ethyl alcohol-water

The electrical conduction of potassium iodide solutions in the ethanol-water system in the temperature range 292–323 K was studied using the conductometric method. Specific and molar electrical conductions of the solutions depending on water and potassium iodide contents were determined.     

Catalytic determination of molybdenum(VI) by means of an iodide ion-selective electrode and a landolt-type hydrogen peroxide-iodide reaction

A trace amount of molybdenum(VI) can be determined by using its catalytic effect on the oxidation of iodide to iodine by hydrogen peroxide in acidic medium. Addition of ascorbic acid added to the reaction mixture produces the Landolt effect, i.e., the iodine produced by the indicator reaction is reduced immediately by the ascorbic add. Hence the concentration of iodide begins to decrease once all the ascorbic acid has been consumed. The induction period is measured by monitoring the concentration of iodide ion with an iodide ion-selective electrode. The reciprocal of the induction period varies linearly with the concentration of molybdenum(VI). The most suitable pH and concentrations of hydrogen peroxide and potassium iodide are found to be 1.5, 5 and 10mM, respectively. An appropriate amount of ascorbic acid is added to the reaction mixture according to the concentration of molybdenum(VI) in the sample solution. A calibration graph with good proportionality is obtained for the molybdenum(VI) concentration range from 0.1 to 160 μM. Iron(III), vanadium(IV), zirconium(IV), tungsten(VI), copper(II) and chromium(VI) interfere, but iron(III) and copper(II) can be masked with EDTA.     

甲基紫分光光度法测定食盐中的添加剂碘酸钾

研究了碘酸钾、碘化钾与甲基紫在盐酸介质中的显色反应 ,反应产物之最大吸收波长λmax为 650nm ,并由此建立了一个简单、快速、实用的分光光度测定食盐中微量碘酸钾的新方法。在最佳实验条件下 ,碘酸钾质量浓度在 0～ 1 60 μg/ 2 5mL内服从比耳定律 ,其线性相关系数r为 0 .9996。本法用于加碘食盐中微量碘酸钾的测定 ,结果与紫外光度法所得结果基本一致     

Bifunctional Onium and Potassium Iodides as Nucleophilic Catalysts for the Solvent-Free Syntheses of Carbonates,Thiocarbonates, and Oxazolidinones from Epoxides

The catalytic potential of organo-onium iodides as nucleophilic catalysts is aptly demonstrated in the synthesis of cyclic carbonates from epoxides and carbon dioxide (CO₂), as a representative CO₂ utilization reaction. Although organo-onium iodide nucleophilic catalysts are metal-free environmentally benign catalysts, harsh reaction conditions are generally required to efficiently promote the coupling reactions of epoxides and CO₂. To solve this problem and accomplish efficient CO₂ utilization reactions under mild conditions, bifunctional onium iodide nucleophilic catalysts bearing a hydrogen bond donor moiety were developed by our research group. Based on the successful bifunctional design of the onium iodide catalysts, nucleophilic catalysis using a potassium iodide (KI)-tetraethylene glycol complex was also investigated in coupling reactions of epoxides and CO₂ under mild reaction conditions. These effective bifunctional onium and potassium iodide nucleophilic catalysts were applied to the solvent-free syntheses of 2-oxazolidinones and cyclic thiocarbonates from epoxides.     

Study of the effect of the chloroallyl group content on the thermal dehydrochlorination of PVC

The chloroallyl group contents of PVC and its low molecular weight fractions, soluble in chloroform or acetone, have been determined on the assumption that the reaction of AgNO₃ with labile chlorine atoms occurs only with the allylic chlorines. Their amount is highest in the low molecular weight fractions. The thermal stability of the polymer in inert atmosphere increases if these groups are removed. Neither the labile chlorine content nor the dehydrochlorination rate (in the subsequent degradation) of the initial polymer, or the fractions insoluble in the two solvents, is affected by heat treatment at 180 for 60 min, whereas the amount of labile chlorine in the low molecular weight fractions increases on heat treatment exceeding 30 min. No direct dependence of the dehydrochlorination rate on the amount of labile chlorine in the polymers under study has been established.     

Reaction of Bis[trialkyl(aryl)arsonium]-1,4-dihydronaphtalene Iodides with Mercuric Iodide in Water-Ethanol Solutions of Potassium Iodide

The reaction of bis[trialkyl(aryl)arsonium]-1,4-dihydronaphtalene iodides with mercuric iodide in water-alcohol solutions in the presence of excess potassium iodide gives rise to bisarsonium triiodomercurates.     

Spectrophotometric Study on Kinetics of Solvatochromism of Methyl Violet in Aqueous Methanol

The kinetics of the reaction of methyl violet with iodide in aqueous methanol system was studied by spectrophotometric method. The rate of reaction of methyl violet in different alcoholic composition in presence of potassium iodide was observed at pH 4 and 6 at various temperatures (298–318 K). Solvatochromic effect was studied in different percentages of methanol (0–50%). Bathochromic shift was observed with the decrease in polarity of solvent. The color change was attributed to molecule's structure, the delocalization of unit electrical charge causes deepening of color and decrease of delocalization causes fading of color due to reduction of dye. Increase in the rate of reaction was observed with increase in alcoholic content and also affected by potassium iodide salt and increased with increase in concentration of potassium iodide. Energy of activation (E_a) and transition energy (E_T) were calculated with the help of kinetic data. Thermodynamic parameters such as enthalpy change of activation (ΔH*), Gibbs free energy change of activation (ΔG*) and entropy change of activation (ΔS*) were evaluated as a function of concentration of solvent and salt.