The arbuzov reaction of triethyl phosphite with elemental iodine

Triethyl phosphite and elemental iodine in solution give transient iodotriethyl-phosphonium iodide which eliminates ethyl iodide to form diethyl phosphoroiodidate. An examination of the ³¹P NMR and IR spectra over the temperature range ?100° ? 0°C fails to disclose any evidence for triethoxydi-iodophosphorane, contrary to a previous claim.     

Influence of the stage of the hair cycle on Cd deposition in hair

Shortly after a single injection of Cd a much higher deposition of Cd was observed in growing hair (anaphase) than in resting hair (telophase). Shifting the time of the administration between 7 d before the onset of matrix production and full hair growth did not appreciably alter the initial deposition in spite of the rapid decline of Cd in blood plasma between the injection and the start of hair growth. After the initial deposition the concentration decreased in growing as well as in resting hair. In growing hair this is attributed to the addition of new matrix containing less Cd due to its declining supply via blood. In the resting hair it may reflect the decline of Cd in the follicular tissue adhering to the hair roots. The study demonstrates that the deposition of internal Cd in hair occurs mainly in those sections of hair growing at the time of the actual intake of Cd into the organism. The quantity of Cd found in a particular section of hair in the absence of external contamination, therefore, indicates first and foremost the quantity of Cd taken up into the blood stream—after ingestion or inhalation—at the time of the actual formation of this section notwithstanding the actual body burden at that time. This work was done under a contract of the International Atomic Energy Agency, Vienna.     

Uniform-sized silicone oil microemulsions: preparation, investigation of stability and deposition on hair surface

Emulsions are commonly used in foods, pharmaceuticals and home-personal-care products. For emulsion based products, it is highly desirable to control the droplet size distribution to improve storage stability, appearance and in-use property. We report preparation of uniform-sized silicone oil microemulsions with different droplets diameters (1.4-40.0 μm) using SPG membrane emulsification technique. These microemulsions were then added into model shampoos and conditioners to investigate the effects of size, uniformity, and storage stability on silicone oil deposition on hair surface. We observed much improved storage stability of uniform-sized microemulsions when the droplets diameter was ≤22.7 μm. The uniform-sized microemulsion of 40.0 μm was less stable but still more stable than non-uniform sized microemulsions prepared by conventional homogenizer. The results clearly indicated that uniform-sized droplets enhanced the deposition of silicone oil on hair and deposition increased with decreasing droplet size. Hair switches washed with small uniform-sized droplets had lower values of coefficient of friction compared with those washed with larger uniform and non-uniform droplets. Moreover the addition of alginate thickener in the shampoos and conditioners further enhanced the deposition of silicone oil on hair. The good correlation between silicone oil droplets stability, deposition on hair and resultant friction of hair support that droplet size and uniformity are important factors for controlling the stability and deposition property of emulsion based products such as shampoo and conditioner.     

Amylose and amylopectin as reagents for the flow-injection determination of elemental iodine

The complexation reactions of elemental iodine with amylopectin and amylose were studied under flow conditions with spectrophotometric signal detection. It was found that the average hydrodynamic molecular weights of amylose and amylopectin are 260 000 and 430 000, whereas the coefficients of sedimentation are 3.44 × 10^?13 and 7.15 × 10^?13 s, respectively. It was demonstrated that the optimum configuration of a flow system depends on the properties of polymer reagent solutions, their viscosity, and the different effects of clath-rate formation with iodine. It was found that the reaction somewhat accelerated in the presence of iodide ions, and amylose as a reagent exhibited the best properties, when the calibration function was described by a linear regression equation. The throughput capacity of this technique was as high as 220 or 140 samples per hour with the use of amylose or amylopectin, respectively. The technique is suitable for the direct determination of elemental iodine in seawater and salt. The detection limit of iodine with amylose was as low as 40 ng/mL.     

The University of Surrey database of elemental composition of human hair

The elemental composition of human hair obtained from different studies at Surrey University over a period of 25 years has been recorded and forms part of a database, for biological and environmental samples, which is being developed. Instrumental neutron activation analysis (INAA), using reactor neutrons, was the principal method employed and from which reported data are presented.Elemental concentrations of Br, Ca, Ce, Cl, Co, Cr, Cs, F, Fe, Hf, K, Mg, Mn, Na, Rb, Sb, Sc, Se, V and Zn were obtained and recorded in the database. Chronological variations in two sets of subjects separated by a period of time of 16 years are also given. Variations in the concentration values of some elements related to the state of health and disease were reported for hair samples collected from subjects suffering from manic depression, senile dementia and breast cancer. Concentration values of some elements with relation to the nationality of subjects from Bulgaria, England, Kenya, Nigeria and Wales are presented and compared. This study is part of on-going research in the analysis of biomedical and bioenvironmental materials. The database is still in its infancy. This revised version was published online in August 2006 with corrections to the Cover Date.     

Diastereoselective thioglycosylation of peracetylated glycosides catalyzed by in situ generated iron(III) iodide from elemental iodine and iron

A facile in situ preparation of Fe(III) iodide from cheap, abundant elemental iodine and iron metal served as an efficient catalyst for the thioglycosylation of peracetylated glycosides with various alkyl and aryl mercaptans. Due to neighboring participation, the anomerically pure β-thioglycosides were obtained in good to high yields with exclusive diastereocontrol.     

Dimerization of a mixed‐carbene PdII dibromide complex by elemental iodine

A monomeric Pd^II complex bearing a mixed carbocyclic/N‐heterocyclic carbene ligand and two bromides was reacted with an excess of elemental iodine, which resulted in the surprising removal of one bromide ligand and dimerization of the mixed‐carbene complex to form di‐μ‐bromido‐bis{[1‐(cyclohepta‐2,4,6‐trien‐2‐yl‐1‐ylidene‐κC ¹)‐3‐(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]palladium(II)} bis(pentaiodide) dichloromethane monosolvate, [Pd₂Br₂(C₂₂H₂₄N₂)₂](I₅)₂·CH₂Cl₂. The dimeric complex features a slightly distorted square‐planar core of two Pd^II centres bridged by two bromide ligands, which lie in the same plane as the seven‐ and five‐membered rings of the bidentate carbene ligand. The counter‐ions in the single crystal were found to be pentaiodide monoanions featuring their typical V‐shape, whereas for the bulk material, a mixture of Br/I interhalides is proposed.     

Selectfluor F-TEDA-BF4 mediated and solvent directed iodination of aryl alkyl ketones using elemental iodine

Reactions of aryl alkyl ketones with methanol solution of elemental iodine and 1-fluoro-4-chloromethyl-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor F-TEDA-BF4) result in the formation of corresponding alpha-iodo ketones, while switch over of the regioselectivity can be directed by using acetonitrile as the solvent and selective iodination of the aromatic site of target molecules is thus achieved.     

Resonance neutrons for determination of elemental content of moss,lichen and pine needles in atmospheric deposition monitoring

Experience in the use of epithermal neutron activation analysis (ENAA) in the monitoring of atmospheric deposition by means of moss, lichens and pine needles is summarized. It is shown that 45 elements (Mg, K, Ca, Al, Cl, Sc, V, Cr, Mn, Fe, Co, Ni (using (n,p)-reaction), Zn, Cu, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, W, Au, Th and U, as well as Ir and Re in pine needles in the presence of anthropogenic pollution by the nickel mining plant) are reliably determined. Examples of the use of lichens, moss and pine needles as biomonitors of atmospheric deposition in Franz Josef Land the Kola peninsula and in the Tver region are given.     

One-pot assembling of selenazolines from elemental selenium,alkenes and acetonitrile

A new method for assembling 1,3-selenazolines by the iodine- mediated reaction of the simplest building blocks such as elemental selenium, alkenes and acetonitrile has been discovered. A proposed mechanism includes the addition of the intermediate selenium iodides to alkene with subsequent solvent interception by the formed seleniranium ion.     

Comparison of elemental composition of hair between osteoporotic and normal women by instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) was carried out on hair samples from a group of twenty patients undergoing a study of osteoporosis. Half of these were judged normal. Fourteen elements were measured but only calcium was found to have a correlation with the disease state. Calcium levels in hair were significantly lower (99% confidence level) in patients with osteoporosis. Conversely, calcium levels in the blood of osteoporotic patients were significantly higher (95% confidence level) than those in normals. Though the group studied was small it is felt that the levels of calcium in hair may be of value in diagnosing osteoporosis.     

Trace analysis of iodine in air with an iodide-selective electrode

Summary For trace determination of iodine in air 40–400 1 air are drawn through a washing bottle filled with 13% K₂CO₃ solution. After neutralization against phenolphthaleine the iodide concentration is measured with an iodide selective electrode using the standard addition method. The slope of the electrode response curve is checked after each sample measurement. This method allows the rapid and simple determination of iodine contents 0.5gmg/m³. The results are compared with those obtained by a kinetic photometric method. Measurements were carried out in the area of Bad Hall (Upper Austria) known for its iodide containing brine springs.This paper is dedicated to Univ.-Prof. Dr. Karl Winsauer on the occasion of his 60th birthday.     

Lipid bilayer deposition and patterning via air bubble collapse

We report a new method for forming patterned lipid bilayers on solid substrates. In bubble collapse deposition (BCD), an air bubble is first "inked" with a monolayer of phospholipid molecules and then touched to the surface of a thermally oxidized silicon wafer and the air is slowly withdrawn. As the bubble shrinks, the lipid monolayer pressure increases. Once the monolayer exceeds the collapse pressure, it folds back on itself, depositing a stable lipid bilayer on the surface. These bilayer disks have lateral diffusion coefficients consistent with high quality supported bilayers. By sequentially depositing bilayers in overlapping areas, fluid connections between bilayers of different compositions are formed. Performing vesicle rupture on the open substrate surrounding this bilayer patch results in a fluid but spatially isolated bilayer. Very little intermixing was observed between the vesicle rupture and bubble-deposited bilayers.     

Electrosynthesis of tetraethylsilane from elemental silicon

Electrolysis of alkylation reagents at silicon-containing electrodes results in alkylsilanes in both cathodic and anodic processes. A mechanism for the reaction is proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 388–389, February, 1995.This work was carried out with the financial support of the Russian Foundation for Basic Research (Grant No. 94-03-09098).     

The formation of charge-transfer complexes from N-vinylindole and chlorine,bromine, and iodine

The reaction of vinylindole with bromine, chlorine, and iodine in CCl₄ solution in the cold leads to the formation of charge-transfer complexes (CTC). The formation of CTC has been confirmed by a study of the physicochemical properties and the IR and UV spectra of the reaction products.     

Syntheses based on elemental phosphorus,sulfur, and their derivatives

This review summarizes the data on the synthesis of various phosphorus-and-sulfurcontaining organic compounds based on the reactions of elemental phosphorus and sulfur and their derivatives (various types of esters of trivalent phosphorus thioacids) with a variety of organic compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1706–1711, October, 1993.     

Radiological and elemental analysis of well cuttings from Rajian oil field,Potohar Basin,Pakistan

Journal of Radioanalytical and Nuclear Chemistry - A study was undertaken to assess the trace elemental concentrations and changes in these elemental concentrations with well depth of Well-09 of...     

Mechanism of positive iodine reactions: Kinetics of oxidation of semicarbazide by iodamine-T, iodine monochloride and iodine

Kinetics of oxidation of semicarbazide (SC) by iodamine-T (IAT), iodine monochloride and aqueous iodine has been studied in aqueous perchloric acid medium. The rate laws followed by the oxidation of SC were determined. The rates decreased slightly with increase in ionic strength of the medium in IAT and ICI oxidations, while the reverse trend was observed with I₂. Decrease in dielectric constant of the medium increased the rates with IAT and ICI, while it decreased the rate in I₂ oxidations. Addition of the reduced product,p-toluene-sulphonamide had no effect on the rate with IAT. Addition of I⁻ had slight negative and positive effects on the rates of oxidations with IAT and ICI, respectively, but the negative effect was considerable in I₂ oxidations. Mechanisms consistent with the observed rate laws have been proposed and discussed. Rate determining steps have been identified and their coefficients calculated. These constants were used to predict the rate constants from the deduced rate laws as [SC], [H⁺] and [I⁻] varied. Reasonable agreement between the calculated constants and experimental values provide support for the suggested mechanisms.