Sealed Glass Tube Research Articles

Preparation, Thermal Behaviour and Crystal Structure of the Basic Mercury(II) Tetraoxotellurate(VI), Hg2TeO5, and Redetermination of the Crystal Structure of Mercury(II) Orthotellurate(VI), Hg3TeO6

AbstractSingle crystals of Hg2TeO5 were obtained as dark‐red parallelepipeds by reacting stoichiometric amounts of Hg(NO3)2 · H2O and H6TeO6 under hydrothermal conditions (250 °C, 10d). The crystal structure (space group Pna21, Z = 4, a = 7.3462(16), b = 5.8635(12), c = 9.969(2)Å, 1261 structure factors, 50 parameters, R[F2 > 2σ(F2)] = 0.0295) is characterized by corner‐sharing [TeO6] octahedra forming isolated chains [TeO4/1O2/2] which extend parallel to [100]. The two crystallographically independent Hg atoms are located in‐between the chains and interconnect the chains via common oxygen atoms. Amber coloured single crystals of Hg3TeO6 were prepared by heating a mixture of Hg, HgO and TeO3 together with small amounts of HgCl2 as mineralizer in an evacuated and sealed silica glass tube (520 °C). The previously reported crystal structure has been re‐investigated by means of single crystal X‐ray data which reveal a symmetry reduction from Ia3¯d to Ia3¯ (Z = 16, a = 13.3808(6) Å, 609 structure factors, 33 parameters, R[F2 > 2σ(F2)] = 0.0221). The crystal structure is made up of a body‐centred packing of [TeO6] octahedra with the Hg atoms situated in the interstices of this arrangement. Upon heating, both title compounds decompose in a one‐step mechanism under formation of TeO2 and loss of the appropriate amounts of elementary mercury and oxygen.

Hydrothermal synthesis and structural characterisation of a vanadium (V) borophosphate cluster containing solid: [Co(en) 3][enH 2]{V 3BP 3O 19}·4.5H 2O

Hydrothermal reaction of VOPO 4·2H 2O and [Co(en) 3]Cl 3 in sealed borosilicate glass tube yielded a vanadium (V) borophosphate cluster based solid, [Co(en) 3][enH 2]{V 3BP 3O 19}·4.5H 2O ( VBPO). Crystal data: monoclinic space group, P2 1/c, Z=4, a=12.0709(7), b=14.2261(8) and c=18.1104(9) Å, β=95.067(1) 0°, V=3097.8(3) A ̊ 3 . Single crystal X-ray diffraction studies revealed that discrete [V 3BP 3O 19] clusters are linked to counter cations and water molecules through a complex hydrogen bonding network.

Preparation and crystal structure of [Bi 3I(C 4H 8O 3H 2) 2(C 4H 8O 3H) 5] 2Bi 8I 30 containing the novel polynuclear [Bi 8I 30] 6− anion

Preparation and crystal structure of the novel compound [Bi 3I(C 4H 8O 3H 2) 2(C 4H 8O 3H) 5] 2Bi 8I 30 are reported. The title compound is prepared by heating of BiI 3 and diethylene glycol at 413 K in a sealed quartz glass tube filled with argon. Deep red single crystals are grown and applied to perform X-ray powder diffraction and X-ray single-crystal diffraction measurements. The compound crystallizes triclinic with space group P-1: Z=2, a=13.217(1) Å, b=15.277(1) Å, c=22.498(1) Å, α=84.33(1), β=73.18(1), γ=67.48(1). [Bi 3I(C 4H 8O 3H 2) 2(C 4H 8O 3H) 5] 2Bi 8I 30 comprises the novel polynuclear [Bi 8I 30] 6− anion and [Bi 3I(C 4H 8O 3H 2) 2(C 4H 8O 3H) 5] 3+ as the cation. Cation as well as the anion can be assumed to represent intermediates between solid BiI 3 and BiI 3 completely dissolved in diethylene glycol.

Network Motifs and Thermal Properties of Copper(I) Halide and Pseudohalide Coordination Polymers with 1, 7‐ and 4, 7‐Phenanthroline

AbstractThe coordination polymers [CuBr(1, 7‐phen‐κN7)] (1a), [CuI(1, 7‐phen)] (2a) and [(CuI)2(1, 7‐phen‐κN7)] (2b) may be prepared by treatment of the appropriate copper(I) halide with 1, 7‐phenanthroline (1, 7‐phen) in acetonitrile. 1a exhibits staircase CuBr double chains, 2a novel quadruple CuI chains. Their thermal properties were investigated by DTA‐TG and temperature resolved powder X‐ray diffraction. On heating, both 1:1 compounds decompose to 2:1 polymers and then finally to CuBr or CuI. With 4, 7‐phenanthroline (4, 7‐phen), CuBr affords both 1:1 and 2:1 complexes (5a, 5b), CuI 1:1 , 2:1 and 3:1 complexes(6a, 6b, 6c) in acetonitrile at 20 °C. 5a and 6a display lamellar coordination networks, with the former containing zigzag CuBr single chains, the latter 4‐membered (CuI)2 rings. A second 2:1 complex [(CuI)2(4, 7‐phen‐μ‐N4, N7)] (6b′) with staircase CuI double chains can be obtained by reacting CuI with 4, 7‐phen in a sealed glass tube at 110 °C. Both 5a and 6a exhibit thermal decomposition pathways of the general type 1:1 → 2:1 → 3:1 → CuX, and novel CuX triple chains are proposed for the isostructural 3:1 polymers 5c and 6c. X‐ray structures are reported for complexes 1a, 2b, [(CuCN)3(CH3CN)(1, 7‐phen‐μ‐N1, N7)] (3c·CH3CN), [CuSCN(1, 7‐phen‐κN7)] (4a), 5a, 6a and [CuCN(4, 7‐phen‐μ‐N4, N7)] (7a).

Comparison of delta18O measurements in nitrate by different combustion techniques.

Three different KNO3 salts with delta18O values ranging from about -31 to +54 per thousand relative to VSMOW were used to compare three off-line, sealed glass tube combustion methods (widely used for isotope studies) with a more recently developed on-line carbon combustion technique. All methods yielded roughly similar isotope ratios for KNO3 samples with delta18O values in the midpoint of the delta18O scale near that of the nitrate reference material IAEA-NO-3 (around +21 to +25 per thousand). This reference material has been used previously for one-point interlaboratory and intertechnique calibrations. However, the isotope ratio scale factors by all of the off-line combustion techniques are compressed such that they are between 0.3 and 0.7 times that of the on-line combustion technique. The contraction of the 6180 scale in the off-line preparations apparently is caused by O isotope exchange between the sample and the glass combustion tubes. These results reinforce the need for nitrate reference materials with delta18O values far from that of atmospheric O2, to improve interlaboratory comparability.

Isothermal phase relations in the Au-Sb-Te system at 350 C

Isothermal phase relations in the Au-Sb-Te system have been investigated at 350°C by the reactions of pure elements of Au, Sb and Te in evacuated sealed glass tubes. Microprobe techniques were employed to determine the composition of each phase of the products. Most efforts were concentrated on the pseudo-binary join between AuSb2, aurostibite and AuTe2, calaverite and the phase relations between these phases and phases in the Sb and Te binary system. Two ternary phases whose compositions are Au1.9(Te2.645b0.46)3.1 and AuSbTe(phase A) were found to exist stably at 350 °C. The XRD pattern of the former phase is almost similar to that of montbrayite reported by BACHECHI (1972), but the composition of the former phase does not agree well with that, and the latter phase does not seem to have been reported as a distinct phase. Montbrayite shows some little solid solution field and has non-stoichiometric compositions. The composition of montbrayite in the present study is not located on the (Au,Sb)2Te3 stoichiometric line, but near the Au2(Te,Sb)3 line. Calaverite, AuTe2 dissolved AuSb2 components up to 11.8 mole per cent and aurostibite, AuSb2 dissolve less than 1 mole per cent AuTe2 component. The phase relations in the system were characterized by the tie line of tellerantimony, Sb2Te3 and gold, Au in the central portion of the diagram, by which independent two ternary systems were introduced, that is, the Au-Sb-Sb2Te3 and the Au-Sb2Te3-Te systems. As a result, right side phases in Figure 3, aurostibite(AuSb2), antimony(Sb) and δ phase ((Sb,Te) solid solutions,ss) in the former system do not coexist with left side phases, calaverite(AuTe2 ss), montbrayite, and tellurium(Te) in the latter system.

A facile preparation of (2,4,6‐14C)‐cyanuric acid under solvent‐free conditions

Abstract(2,4,6‐14C)‐Cyanuric acid was prepared from 14C‐urea by the heterocyclization of the latter in the presence of ammonium chloride. This procedure involves solvent‐free fusing of the reactants in a vacuum sealed glass tube. The product was purified by ion‐exchange column chromatography using Sephadex SE C‐25. A radiochemical yield of 60.5% was obtained based on 14C‐urea and the product had a specific activity of 19.06 mCi/mmol. Copyright © 2002 John Wiley & Sons, Ltd.

Measurements of JNO 3− in snow by nitrate-based actinometry

Chemical actinometry was used to measure nitrate photolysis rate coefficients, J NO 3 − , on and in snowpack at Summit, Greenland. Sealed glass tubes containing nitrate and a hydroxyl radical trapping system were buried in snow and exposed for between 2 and 24 h. Average J NO 3 − values for 2-h midday exposures in early June on surface snow were 10–14×10 −7 s −1. Averages over 24 h were 3.5–4.5×10 −7 s −1. These values reflect the integrated photon flux and also any variation of the nitrate photolysis rate with temperature. Attenuation of J NO 3 − within the firn was 0.03–0.04 cm −1 for 24-h exposures and 0.08 cm −1 for a 2-h exposure. Different attenuation coefficients may relate to differential light penetration due to changes in sun angle over the course of 24 h.

PHASE SEPARATION IN (Fe,Co)1 xS MONOSULFIDE SOLID-SOLUTION BELOW 450 C, WITH CONSEQUENCES FOR COEXISTING PYRRHOTITE AND PENTLANDITE IN MAGMATIC SULFIDE DEPOSITS

Phase relations for (Fe,Co) 1‐xS coexisting with cobalt pentlandite have been studied up to 450 °C using sealed silica glass tube experiments. The (Fe,Co) monosulfide solid-solution with the NiAs-type structure (Fe,Co- mss) unmixes abruptly below 425°C, to coexisting Fe-rich (Fe,Co-mss1; 1C structure) and Co-rich (Fe,Co- mss2; 3C structure) phases. For bulk compositions with 52.0 at.% S, the equilibrium Fe,Co-mss1 solvus is located at about 0.83 molar Fe/(Fe + Co) at 400 °C and progressively diverges toward the Fe1‐xS end-member composition with decrease in temperature to 0.98 molar Fe/(Fe + Co) at 105 °C. At 400°C, the equilibrium Fe,Co-mss2 solvus is at about 0.37 molar Fe/(Fe + Co) and does not appear to vary significantly with decrease in temperature. There is a metastable solvus within the equilibrium miscibility-gap, with a critical temperature at 425 °C between 0.45 and 0.50 molar Fe/(Fe + Co), as indicated by single-phase products that persist even with prolonged annealing. A narrow field of spontaneous phase-separation is centered at 0.75 molar Fe/(Fe + Co), and results in satellite reflections of h0l NiAs-type subcell reflections in products quenched from a high temperature (800 °C). The miscibility gap in Fe,Co-mss is similar to the phase separation of mss in the system Fe‐Ni‐S. However, phase separation occurs at a slightly higher temperature in Fe,Co-mss (between 425 and 400°C) than in mss (between 400 and 300°C), and is initially discontinuous.

Analysis of pyrolysis products of dimethylamphetamine.

This study examines the pyrolysis products of dimethylamphetamine (DMAMP) and its pyrolysis mechanism. A sealed glass tube, in which DMAMP-HCI was placed, was wrapped with pyrolysis-foil and heated at the Curie point of the pyrolysis-foil. The pyrolysis products of DMAMP were detected by gas chromatography-mass spectrometry (GC-MS), headspace (HS)-GC-MS and liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). DMAMP-d6-HCl, in which all the hydrogen atoms of the two methyl groups of DMAMP were substituted with deuterium atoms, was pyrolyzed to investigate the elimination and transformation reactions of the methyl group. Methamphetamine (MAMP) and amphetamine (AMP) were produced via demethylation reaction by heating DMAMP, and the maximum amounts of MAMP and AMP were about 31.8% and 13.7% of the starting DMAMP at 358 degrees C and 386 degrees C, respectively. The reactions of a chlorine anion and DMAMP with a methyl group eliminated from the dimethylamino group of DMAMP resulted in the formation of methyl chloride and benzylethyltrimethylammonium, respectively. These results indicate that one of the demethylation and methylation reactions occurs in the form of a methyl cation.

NMR Study of Hydrothermal Reactions of Dichloromethane with and without Alkali

Abstract Hydrothermal reactions of considerably concentrated (ca. 1 M; M = mol dm-3) dichloromethane, CH2Cl2, were investigated with and without alkali in the temperature range of 150—300 °C by using batch reactors, such as an autoclave and sealed glass tubes. 1H, 2H, and 13C NMR spectra were taken at room temperature as a function of reaction time to analyze the quenched reactants, intermediates, and products. In the presence of NaOH at 2 M, the complete dechlorination was achieved in 270 min at 250 °C and in 60 min at 300 °C. Such gaseous by-products as CO, CO2, and H2 were generated by the decomposition of the disproportionation product, HCOO-. Without alkali, CH2(OH)2 could be detected by 1H and 13C NMR as an intermediate in the hydrolysis of CH2Cl2, before such Cannizzaro products as methanol and formate ion were formed. The mechanism of the hydrothermal reactions of CH2Cl2 is discussed in terms of the hydrolysis intermediate, CH2(OH)2.

Thermal dealkylation of dodecylbenzene and dodecylcyclohexane

Rate constants for thermal decomposition of isotopically labeled dodecylbenzene and dodecylcyclohexane doped in n-C 16 and crude oil matrices were measured in sealed glass tubes at 310–360°C. The rate varied by a factor of 1.5 in the various matrices, but there was no clear relationship with matrix composition. The decomposition rate of dodecylcyclohexane is very close to that of n-C 16, and comparison to literature data suggests that the activation energy is similar as well. The decomposition rate of dodecylbenzene is about 4 times faster than of n-C 16, and the activation energy may also be lower. This is consistent with the dealkylation of aromatics to form additional saturates as being a significant reaction during the early stages of oil maturation.

Advances in the radiotherapy of gynecologic malignancies.

The use of radiation in the treatment of gynecologic malignancies dates back to the early years of the century. The particular anatomy of the vagina and uterus allowed early investigators to readily use primitive radiation sources in the therapy of cervical cancer. Margaret Abigail Cleaves, a New York electrotherapist, is credited with being one of the first to use radium to treat cervical cancer. In 1903, she described how she applied a sealed glass tube containing radium to an advanced cervix cancer [1]. Impressed by the result, she then developed a specially shaped x-ray tube with a long neck that could be used for transvaginal irradiation of the cervix [2]. The first intrauterine radium applicator was made by Wickham and Desgrais in Paris around 1908, and in 1909 Forsell in Stockholm reported on the treatment of 32 cervix cancer patients with silver tubes containing radium, coining the term brachytherapy for his treatment [3]. Over the next several decades, an understanding of anatomy and dose delivery allowed the development of standardized treatment systems at Stockholm, Paris, and Manchester. With advances in external beam equipment, it became possible to combine brachytherapy with external beam radiotherapy to optimize treatment. Technical advances in treatment planning and dose delivery equipment continue to be made at a rapid rate, the clinical benefits of which are being realized.

The high temperature titration of biogenic silica

A new method has been developed for measuring biogenic silica (amorphous) in marine sediments. It is based on the Högbom–Urey reactionCaCO3+SiO2(biogenicsilica)→CaSiO3(wollastonite)+CO2.The reaction is carried out in evacuated sealed glass tubes with added excess reagent grade calcite at 500°C for 3d. The product CO2 is measured in a calibrated manometer. The dependence of the reaction on time, temperature, product CO2 pressure, and other factors is examined.

Determination of traces of water in liquid dinitrogen tetroxide‐nitric oxide propellant mixtures by Fourier transform proton magnetic resonance spectrometry

AbstractLiquid dinitrogen tetroxide, N2O4, and mixed oxides of nitrogen as used as rocket propellant oxidizers, contain the products of the reaction of N2O4 with adventitious water. The determination of the total concentration of water and water‐derived species, called the water equivalent content, is essential in view of the effect of the hydrolysis products upon the rate of corrosion of containment metals and the physical state of the corrosion products. High field Fourier transform proton magnetic resonance spectrometry has now been validated for the direct measurement of water equivalent for MON blends up to MON‐3, without prior oxidation. Oxidation does, however, give slightly better precision. The technique is shown to be a reliable, absolute method for the determination of water equivalent contents as low as 0.003 wt% and up to at least 0.2 wt%. The precision of the method in this range is within 5%: it is estimated that the water equivalent content could be determined at levels as low as 0.0001 wt%. Samples of N2O4 prepared for NMR analysis are stable in sealed glass tubes for more than 1 year.

Characterization of tetramethylammonium hydroxide thermochemolysis products of near-shore marine sediments using gas chromatography/mass spectrometry and gas chromatography/combustion/isotope ratio mass spectrometry

The study describes the application of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) to characterize the molecular and compound-specific stable carbon isotope composition, respectively, of tetramethylammonium hydroxide (TMAH) thermochemolysis products of organic matter present in marine sediments. The objective of the study was to examine the usefulness of TMAH thermochemolysis products in identifying organic markers of terrestrial-derived sources in marine sediments. ‘Batch-wise’ thermochemolysis conditions (excess TMAH. 250 °C, sealed glass tube, 30 min) were used on sediments and standards. Compound-specific isotope analysis (CSIA) of standards showed no evidence of isotopic fractionation at methyl carbon during methylation of a number of phenolic acid and fatty acid compounds. It was also shown that no appreciable isotopic affect occurs during bond cleavage and methylation of fatty acid groups of the standard triglyceride, tricaprin. These preliminary tests indicate that the initial δ 13C composition of chemical markers containing acidic functional groups can be obtained by measuring the δ 13C of the corresponding methyl esters and/or ethers after TMAH methylation. In order to confirm the number of methoxy groups in lignin-derived markers, tetraethylammonium hydroxide was employed. Useful chemical markers found in near-shore sediments in reasonable abundance were a range of fatty acids, vanillin, vanillic acid and P-coumaric acid. Preliminary results of CSIA of these phenolic markers and selected saturated fatty acids in three different marine sediment cores are reported.

Temperature-Jump Relaxation Magic-Angle Spinning NMR Study of the Methyl tert-Butyl Ether Reaction in a Boron Pentasil Zeolite

Temperature-jump relaxation magic-angle spinning NMR experiments are for the first time applied to study a heterogeneously catalyzed reaction. A temperature jump from 20 to 100−150 °C creates a nonequilibrium state of the system consisting of methyl tert-butyl ether (MTBE), methanol, and isobutene, which are adsorbed on a boron pentasil zeolite in a sealed glass tube. The rate constants of MTBE decomposition and formation were determined, and the corresponding apparent energies of activation are 51 and 32 kJ mol-1, respectively. The NMR findings are in agreement with experimental results obtained in a fixed bed reactor or in an autoclave.

R‐134a compatible lubricants based on C4‐C6 esters of pentaerythritol and polyalkyleneglycol

AbstractThe results of work intended to produce inexpensive, synthetic lubricants compatible with R‐134a using waste carboxylic acids C4‐C6 as the base are presented in this paper.The suitability of the products synthesised was first evaluated considering their physical and chemical properties, and their thermostability determined by the standard Philipp test (sealed glass tube method). Two ester bases were then selected for further testing — a pentaerythritol esterified with C4‐C6 monocarboxylic acids and a polyalkyleneglycol similarly esterified with monocarboxylic acids C4‐C6.The base oils chosen were tested for their corrosive action on metals in the presence of water in different concentrations. The pentaerythritol ester proved to have the most advantageous properties at that stage. The results of the laboratory tests have been corroborated by trials conducted on real refrigerating compressor systems. Only the lubricant that was obtained using pentaerythritol esterified with monocarboxylic acids C4‐C6 as the base withstood the severe test.

Containerless protein crystallization in floating drops: application to crystal growth monitoring under reduced nucleation conditions

A micromethod was developed for the batch crystallization of proteins under conditions were the solution has no contact with the container walls. Drops of crystallization solutions (5 to 100 μl) are placed at the interface between two layers of inert and non-miscible silicone fluids contained in square glass or plastic cuvettes. The densities of the fluids are either lower or higher than those of the major precipitating agents of macromolecules, including aqueous solutions containing salts, polyethylene glycols or alcohols. Several proteins and a spherical plant virus were crystallized in the temperature range 4°C–20°C using this set-up. A thermostated device was built for the dynamic control of the temperature of crystallization drops and the monitoring of crystal growth by video-microscopy. In all cases, the habit of the crystals grown in floating drops are identical to those of controls grown in sealed glass tubes without silicone fluid. The comparison of the number of crystals in drops kept under one layer of fluid and in floating drops of the same volume indicates that heterogeneous nucleation is minimized when protein crystallization is performed in floating drops. The advantages and limitations of this novel containerless crystallization method are discussed.

Partitioning of platinum-group elements (Os, Ir, Ru, Pt, Pd) and gold between sulfide liquid and basalt melt

New measurements on partitioning of platinum-group elements (PGE) Os, Ir, Ru, Pt, Pd, and Au between (Fe,Ni)-sulfide liquid and basaltic melt using low pressure, sealed silica glass tube, and controlled atmosphere methods at 1200–1250°C show an extremely wide variation, which spans much of the range reported in the literature. In spite of their geochemical coherence in natural high-temperature assemblages, PGE-Au apparently behave as seven different metals in individual laboratory experiments with silicate melts. Sulfide/silicate partition coefficients, D, generally increase with run time, in a manner consistent with either serial change in chemical state of the metals in the silicate melt or passivation of alloy phases. Ruthenium is the only metal presently investigated that exhibits reversible behaviour. Summary partition coefficients for the lowest PGE contents investigated under reducing conditions and low Ni contents remain unchanged, except for the addition of a value of (4.4 ± 2.4) × 10 3 for Ru. Absence of interference from the nugget effect and homogeneity and equilibration of silicate melt in the earlier experiments is demonstrated by new measurements on Ir in different grain-size fractions of glass. An additional set of partition coefficients for 37 mol% NiS and 100–1000 ppm PGE in the sulfide is: D(Os) = (30 ± 6) × 10 3, D(Ir) = (26 ± 11) × 10 3, D(Ru) = (6.4 ± 2.1) × 10 3, D(Pt) = (10 ± 4) × 10 3, and D(Pd) = (17 ± 7) × 10 3.