Sodium Biphenyl Research Articles

Structure of alkali biphenyl ion pairs in solution and in the solid state

NMR experiments on sodium biphenyl (NaBp), potassium biphenyl (KBp) and rubidium biphenyl (RbBp), dissolved in various solvents are summarized with emphasis on the structural information which can be obtained from such experiments. The crystal structures of NaBp.2Tg (Tg = triglyme), KBp.2Ttg and RbBp.2Ttg (Ttg = tetraglyme) are discussed, in relation to the NMR results obtained for these systems in solution. In the solid state these crystals may be considered to be built up of solvent separated ion pairs. Magnetic experiments are reported for single crystals of the three systems. Susceptibility measurements revealed a ferromagnetic coupling in NaBp.2Tg and KBp.2Ttg and an antiferromagnetic coupling in RbBp.2Ttg. All crystals exhibit an exchange narrowed ESR line, with an orientation dependent linewidth. From the resonance positions the molecular g tensor of the biphenyl anion could be derived. The orientation dependent linewidth is due to dipolar interactions between the spins. A quantitative explanation of it could not be given at present.

Determination of chlorine in organic materials by potentiometric titration after decomposition with sodium biphenyl

Determination of chlorine in organic materials by potentiometric titration after decomposition with sodium biphenyl

On the polymerisability of 2-alkenylfurans with anionic initiators

Various attempts to induce the anionic polymerisation of 2-vinylfuran and some of its homologues were carried out. Negative results were obtained, except with sodium biphenyl in hexamethylphosphotriamide, a system which gave limited yields and not a living polymerisation. The results are interptreted on the basis of side reactions of the furan ring marring the normal vinyl propagation, A critical discussion of previous conflicting reports is also given.

On the association phenomena of poly(methyl methacrylate) in nonpolar theta solvents

AbstractOn a sample of poly(methyl methacrylate) prepared by an anionic polymerization technique with sodium biphenyl in tetrahydrofuran at –78°C, abnormal cloud‐point curves in nonpolar theta solvents, p‐xylene, and carbon tetrachloride were observed. The effect of solvent polarity on precipitation behavior of the sample solutions was examined. It is found that the more polar the solvent used, the more normal the cloud‐point curve becomes. Osmometry on the sample solutions in p‐xylene yielded much higher molecular weights than those obtained in a good solvent (toluene) and in a polar theta solvent (acetonitrile). The results obtained show that poly(methyl methacrylate) molecules prepared in this manner are liable to associate with each other in nonpolar media. This feature is considered to be responsible for the observed anomalies in the cloud‐point curves. This type of association is discussed and compared with the other two kinds of association phenomena reported in the literature.

Indirect determination of fluorine in organic compounds by atomic absorption spectrometry

In order to determine fluorine in organic compounds, the authors attempted the indirect determination of fluorine by decomposing fluorine-containing derivatives with sodium biphenyl, followed by atomic absorption spectrometry of iron in MIBK phase. The recommended procedure is as follows: The aqueous solution seperated after the decomposition with sodium biphenyl, was adjusted its pH at 3.0 with 0.2 N hydrochloric acid. To 5 ml of this solution, was added one ml of an excess of a ferric chloride solution which contains 10 μg/ml of Fe and then one ml of 2.5% ammonium thiocyanate solution. Excess iron was extracted with 2 ml of MIBK as ferric thiocyanate and the iron content extracted was measured by atomic absorption spectrometry. Fluorine is determined indirectly by this method and the calibration curve was linear in the range of (0.56.0) μg/ml. Metals which form more stable fluorine complexes than Fe (III) interfer, but the anions except CN- does not disturb the measurement.

Determination of fluorocarbon in blood.

Because fluorocarbons can dissolve relatively large quantities of oxygen and carbon dioxide, there is considerable interest in utilizing them to develop new methods of extracorporael circulation, artificial red blood cells, and liquid breathing techniques. A method for the assay of fluorocarbon in blood is presented. The fluorocarbon is extracted from the blood with toluene, and fluoride is released from the fluorocarbon in the toluene extract by reaction with sodium biphenyl. The inorganic fluoride is then extracted with aqueous sodium acetate, the pH of the extract is adjusted, and the activity of the fluoride ion is read with a fluoride-specific ion electrode. The assay was effective for fluorocarbon concentrations in the range of 1 to 30 ppm.

Collaborative Study of a Method for the Analysis of Dry Methoxychlor Formulations

A collaborative study has been completed on a method for determining methoxychlor content in dry formulations. The method is based on a total halogen determination plus a selective, qualitative thin lay chromatographic (TLC) measurement to establish the p,p'-methoxychlor is the primary halogen-containing organic species present in the formulation. After extraction of the sample with toluene, the toluene solution of methoxychlor is treated with sodium biphenyl to convert all halogen to the halide. The halide is then extracted with a solution of nitric acid and titrated with silver nitrate according to the Volhard procedure or potentiometrically, using a pH meter assembly. Based on the results obtained from 7 collaborators, the standard deviation of the method is about 0.48% at the 50% level. The qualitative TLC measurement is made on an aliquot of the initial toluene extract, using a selective halogen detection system. The method has been adopted as official first action.

Chemical and Thermal Aspects of Pesticide Disposal

AbstractPesticides, when treated with sodium biphenyl reagent, were decomposed to the extent of 80 to 99%. However, when these compounds were treated with a mixture of metallic sodium and liquid ammonia, 15 of the 19 compounds were completely degraded. When metallic lithium was substituted for metallic sodium, the mixture was less effective but still completely degraded 8 of 19 compounds. The decomposition products resulting from these reactions were not tested for toxicity.The pesticide formulations were incinerated, either singly or mixed, at 900C. Analyses of the volatile products revealed that at least four hazardous gases (chlorine, hydrogen chloride, hydrogen sulfide, and nitric acid) were produced.

Determination of Organically Bound Fluorine Using Sodium Biphenyl Reagent and a Fluoride-Specific Ion Electrode

A simple, accurate, and specific method for direct determination of carbon-bonded fluorine is described for various aromatic compounds of pharmaceutical interest, containing as little as 4% fluorine. Sodium biphenyl reagent was utilized for quantitative liberation of bound fluorine; a fluoride-specific ion electrode was used, in conjunction with a high ionic strength buffer solution, for direct measurement of the liberated fluoride. Incorporation of a subsequent „oxidation”︁ step, using hydrogen peroxide, resulted in quantitative determination of fluorine for certain organo-fluoro compounds which were difficult to ionize completely using a modified oxygen flask combustion technique. It was possible to determine fluorine routinely for up to 20 samples in an 8-hr. period. Precision and accuracy studies are included.

Thin-layer chromatographic determination of the β-fluoroethyl ester of xenyl acetic acid (M 2060) in the technical product and in 2% liquid formulations

Two methods, based on preliminary thin-layer chromatography, have been developed for determining the β-fluoroethyl ester of xenyl acid in the technical product and the 2% liquid formulation. The acaricide, or a convenient amount of the formulation, is dissolved in acetone and the solution is spotted on a thin-layer chromatographic plate. After development and identification by means of a UV lamp, the M 2060 area is isolated, detached and eluted. In the case of the determination of the active ingredient in the technical product, hydrolysis is conducted on the eluate residue, followed by titration of the resulting xenyl acetic acid. In the liquid formulation, dehalogenation of the eluate residue is carried out with sodium biphenyl and fluorine is determined colorimetrically, by means of cerium nitrate and alizarin complexone, under special conditions.

Rapid Analysis of Halogenated Organic Insecticides in Aqueous Animal Dips, Using Sodium Biphenyl

Abstract Pertinent parameters for an analytical method, using sodium biphenyl, are presented for the quantitative estimation of toxaphene, lindane, DDT, methoxychlor, dieldrin, chlordane, ronnel, Ruelene, eoumaphos, trichlorfon, and naled in aqueous dips. The method is applicable to both insecticide emulsion and wettable powder dips.

Determination of traces of organic fluorine in hydrocarbons

Organic samples containing down to 0.2 ppm of fluorine may be analysed by first converting the organic fluorine into inorganic fluoride by treatment with sodium biphenyl, followed by removal of diverse cations with a cation-exchanger before conductometric titration with lanthanum acetate. Effect of variables, sources of error, and control of reagent blanks are evaluated. For the 0.2-1 ppm organic fluorine level in synthetic blends made from 1-fluoronaphthalene, the relative estimated standard deviation was 7.8%; the mean relative error was 6.2 %. Based on the mean range from duplicate analyses of catalytically processed samples in the C(12) boiling range, at the 1 ppm fluorine level the estimated standard deviation was 0.087 ppm of fluorine. One analyst can determine the fluorine content of about 12 samples in 8 hr.

Analysis of Dursban in Livestock Dips and Sprays

Abstract Chemical and spectrophotometric procedures for Dursban in emulsifiable concentrates, dips, sprays, and hair and hide extracts are compared. Infrared spectrophotometric methods are more rapid, simple, free from interference, and specific than the UV or sodium biphenyl methods.

Microdetermination of trace quantities of organic chloride by combustion and microcoulometry: Application to low-boiling liquids

Methods for the determination of trace amounts of chloride in organic materials include procedures based on the reaction with sodium biphenyl reagent, the ASTM wick lamp combustion, and modifications of the tube combustion for the decomposition of the organic material. Methods utilizing potentiometric, amperometric, or colorimetric techniques have been reported to measure the chloride in the combusted material. Summaries of these methods are given in subsequent sections of this report. In addition to these methods we have applied a combustion tube technique utilizing a microcoulometric titration to determine trace chlorides in low-boiling organic liquids (kerosene range). This method is based on the work of Coulson et al. ( 3). It is possible by this technique to complete an analysis in 3–5 minutes as opposed to between 1–3 hours by the other methods. Preliminary results indicate comparable precision. In the analysis, a sample (up to 5 μl) is injected into a vaporization chamber and carried with nitrogen to the combustion zone which is maintained at 800 °C. The nitrogen flow is mixed with oxygen and passes through the combustion tube into the titration cell. The chloride is titrated according to the following reactions: Ag ++X−→ AgX Ag°→ Ag ++ e and the area of the recorded peak measured. Investigation will be carried out to expand the method to include high boiling liquids and solids.

Rapid Quantitative Vatside Check Test For Chlorinated Hydrocarbons in Aqueous Emulsions: Toxaphene and Lindane

Abstract A simple and rapid field test is described for the vatside determination of toxaphene and lindane in aqueous emulsions used for the eradication of ectoparasites in livestock. With appropriate modification, the test should also be useful for aqueous emulsions of other chlorinated hydrocarbons. The chlorinated hydrocarbon is “salted-out” of emulsion and extracted into an organic solvent, and the extract is reacted with sodium biphenyl, which strips the molecule of organic halogen. After solution of reaction products in a glycol-alcohol solvent and adjustment of pH, the resultant chloride is titrated with silver nitrate to a pink end point with 2″,7″-dichlorofluorescein. All procedures except extraction are carried out in one vessel and there is no need for special equipment. A field worker can perform an analysis in 15 minutes.

Narrow molecular weight distribution polystyrenes

AbstractA study of the scope and limitations of the anionic polymerization of styrene and substituted styrenes under conditions in which a chain termination reaction is lacking was made. Under these conditions polymers of very narrow molecular weight distributions were obtained. Ultracentrifuge data are presented as evidence confirming the formation of narrow distributions. All reagents used were carefully purified and subsequently were not exposed to the atmosphere. Standard procedure was to conduct the polymerizations by adding monomer solution slowly to initiator solution. Deviations from this procedure were designed to study various reaction conditions. Monomers used were styrene, α‐methylstyrene, and m‐ and p‐vinyltoluene. Solvents used were tetrahydrofuran, tetrahydropyran, 2‐methyl‐tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Initiators used were sodium–naphthalene, sodium–biphenyl, sodium–α‐methylstyrene, sodium–phenanthrene, and lithium–naphthalene. The choice of solvent had a great effect on the course of the polymerization and the temperature at which narrow distribution polymers could be produced. Solvents promoting rapid initiation and relatively slow propagation were best, and those promoting the reverse situation tended to give side reactions leading to termination and abroad distribution polymer. The order of promotion of rapid initiation and slow propagation for these solvents is dioxan > tetrahydrofuran > ethylene glycol dimethyl ether > diethylene glycol dimethyl ether. In dioxane solutions monodisperse polymer was prepared under a wide range of conditions. Monodisperse polymer could not be prepared under the most favorable conditions in diethylene glycol dimethyl ether. These effects were interpreted in terms of ion pair separation. Other factors which might lead to broad distribution polymers were examined. The age of the initiator was found to be very important, order initiator solutions giving broad distribution polymers. Aged initiator solutions were found to evolve hydrogen when allowed to react with water; freshly prepared initiator solutions evolved on hydrogen. In the presence of toluene there was chain transfer to the methyl group giving a broad distribution polymer. Similar transfer to benzene at the ring gave termination before polymerization was complete. Rusty iron, Fe2O3, and Fe3O4 adversely effected the course of polymerizations giving broad distribution polymers. Hydrogen‐reduced iron in the reaction mixture resulted in only minor deviation from narrow distribution.

Techniques Useful for Sodium Biphenyl Determination of Micro Quantities of Organic Chlorine

Techniques Useful for Sodium Biphenyl Determination of Micro Quantities of Organic Chlorine

Determination of Fluorine in Quantitative Organic Microanalysis

Determination of fluorine in organic microanalysis has become increasingly important because of the large number and variety of organic fluoro compounds being synthesized. Because of its peculiar properties, conventional micromethods for halogen determinatlon are not applicable without modification. The principal steps in the determination of fluorine are: decomposition to convert organically bound fluorine to the fluoride ion from ions interfering in the subsequent step, and measurement of the fluoride ion. Methods of decomposition include catalytic oxidation, alkali metal or carbonate fusion, reduction with sodium biphenyl, and heating with concentrated sulfuric acid. Fluoride ion has been separated by the volatility of silicon tetrafluoride, steam distillation of fluorosllicic acid, or ion exchange resin. It has been determined gravimetrically as lead chlorofluoride, volumetrically with sodium hydroxide or thorium nitrate, colorimetrically with ammoninm molybdate, and potentiometrically with calcium ions. (auth)

Determination of Organic Halogen with Sodium Biphenyl Reagent

Determination of Organic Halogen with Sodium Biphenyl Reagent