Cryoscopic studies of aqueous solutions of tartaric acid,sodium hydrogen tartrate,potassium tartrate,sodium dihydrogen citrate,potassium dihydrogen citrate,disodium hydrogen citrate,sodium citrate and potassium citrate

Freezing temperature lowerings of aqueous solutions of tartaric acid, sodium hydrogen tartrate, sodium dihydrogen citrate, potassium dihydrogen citrate, disodium hydrogen citrate, sodium citrate and potassium citrate were determined. These values and those taken from the literature for potassium tartrate were used in the determination of the osmotic and activity coefficients in the studied systems, via the numerical integration of the Gibbs–Duhem equation.     

The assay of sodium citrate and sodium potassium tartrate by cation exchange and non-aqueous titrimetry

Sodium citrate and sodium potassium tartrate are assayed by passing aqueous solutions of the salts through cation exchange resin columns, concentrating the effluents from the columns, and then titrating the effluents with standard sodium hydroxide solution. Sodium citrate is assayed by titrating a solution of the salt in glacial acetic acid with standard acetous perchloric acid, the end-point being detected potentiometrically; sodium potassium tartrate is assayed by stirring the salt in excess standard acetous perchloric acid, and then backtitrating the excess acetous perchloric acid with standard acetous potassium acetate, the end-point being detected potentiometrically.     

Sarcosinium tartrate

In the title compound, C₃H₈NO₂⁺·C₄H₅O₆⁻, the sarcosinium cation and semi-tartrate anion are held together by a three-dimensional network of O—H⃛O, N—H⃛O and C—H⃛O hydrogen bonds. The structure may be described as an inclusion compound with the semi-tartrate anion as the host and the sarcosinium cation as the guest.     

Antimony anchored in MoS2 nanosheets with N-doped carbon coating to boost potassium storage performance

Potassium ions batteries (PIBs) have been considered as promising energy storage systems owning to potassium rich natural abundances. However, the difficult reaction kinetics and poor cycling of electrode restrict the further development of PIBs. In this work, antimony anchored in MoS₂ nanosheets with N-doped carbon coating (Sb/MoS₂/NCs) are prepared and evaluated as anode for PIBs. In the unique Sb/MoS₂/NCs structure, the volume expansion of Sb particles could be effectively buffered by the around MoS₂ structure. The defects in MoS₂ nanosheets provide more electrochemical reaction sites for sufficient K⁺ insertion/extraction. Furthermore, the N-doped carbon can further accommodate the volume expansion and improve the electronic conductivity of Sb/MoS₂/NCs composites. Due to the above advantages, the Sb/MoS₂/NCs anode delivers a capacity of 235 mAh/g at 50 mA/g after 78 cycles. This work provides a prospective strategy to design advanced anode materials for PIBs using MoS₂ and antimony composites.     

Solid-state study of hydrazonium tartrate and deuterated hydrazonium tartrate enantiomers

A study of the crystallographic, optical, and thermochemical properties of hydrazonium tartrate and deuterated hydrazonium tartrate enantiomers is described. Crystals of the enantiomers are orthorhombic with a tetramolecular cell. The space group is P2₁2₁2₁ with the lattice parameters a₀ = 7.640 ± 0.002 Å, b₀ = 13.441 ± 0.003 Å, and c₀ = 7.029 ± 0.002 Å. No change in lattice parameters is observed on deuteration. Optical second harmonic powder analysis shows the crystals to be phase matchable at 1.06 μm with d^2ω = 11 d^2ωα-SiO₂. The optical nonlinearity being unaffected by deuterium substitution is attributed to the nonlinear electronic polarizability of the hydrogen bonds. Crystals are transparent from 239 nm to 1.61 μm. Deuteration shifts the long wavelength cutoff to 2.07 μm, without affecting the band edge.     

Synthesis of divinyl tartrate

Summary Divinyl tartrate was synthesized.     

Polarographic determination of butorphanol tartrate

A new indirect polarographic method is proposed for the determination of butorphanol tartrate in the injectable solution form (Stadol). Direct-current polarography and differential pulse polarography (DPP) were applied for the study of authentic butorphanol and its injectable solution form in alkaline medium after nitration with 1 M potassium nitrite in presence of 1 M hydrochloric acid. The standard addition method was employed for the evaluation of the results and the mean percentage found for the injectable solution form was 99.2 +/- 1.0.     

l‐Prolinium tartrate

In the title salt, C₅H₁₀NO₂⁺·C₄H₅O₆^?, proline exists as a cation and the tartaric acid as a semi‐tartrate anion. The semi‐tartrate ions form hydrogen‐bonded strings along the c axis. These strings are interconnected through the proline mol­ecules, forming a layered network parallel to the bc plane. The proline mol­ecules, however, do not directly interact among themselves, except for a weak C—H?O hydrogen bond.     

Polymorphism of potassium-sodium tartrate tetrahydrate

A geometric model of phase equilibria between NaKC₄H₄O₆ · 4H₂O crystal hydrate polymorphs was suggested. An analytic equation for its thermodynamic potential was obtained, and the temperature dependences of heat capacity and polarization were found. An analytic form of the interrelation between the anisotropic characteristics of NaKC₄H₄O₆ · 4H₂O was obtained, and their temperature dependences were calculated over a wide temperature range including polymorphic transition points.     

Spectrofluorimetric Determination of Antimony

Abstract

A spectrofluorimetric procedure for the determination of micromolar concentrations of antimony(III) was devised based on its reduction of cerium(IV) to produce fluorescent cerium(III). The method was optimized and the reaction was fast enough in hydrochloric acid media without the need for iodide or osmium(VIII) as catalysts. Linear calibration graphs were obtained in the range 1-10 10^?6M. The standard deviation for determining 5 × 10^?6M antimony(III)(10 times) was 1.43 × 10^?7M and the relative error was -3.4 %. The method was applied to the determination of antimony(III) in its mixture with antimony(V), total antimony was later determined after reduction with mercury metal in deoxygenated solutions. The affect several reducing agents on the determination of antimony-was also examined.     

Production and purification of tartrate dehydrogenase

Tartrate dehydrogenase (TDH) is a stereospecific intracellular enzyme produced byPseudomonas putida. Several methods for separation of nucleic acids from the proteins in cell homogenate were compared in this study. These methods included precipitation (using streptomycin sulfate, manganous sulfate, and protamine sulfate) and aqueous two-phase extraction. Under optimal conditions of separation, a single-step aqueous two-phase extraction followed by back-extraction of the enzyme from enzyme-rich PEG-phase resulted in77% recovery of enzyme. This compared favorably with 50% enzyme recovery using protamine sulfate treatment. Furthermore, the remaining enzyme activity was accounted in the nucleic acid-rich dextran phase and the spent-PEG phase, suggesting that a multistep extraction process would increase enzyme recovery even more. Under the conditions of aqueous two-phase extraction, the selectivity of proteins over nucleic acids was 30, indicating a high degree of separation of proteins and nucleic acids in this process. The experimental data and their implications are presented.

     

Thermal stability of phosphinated diethyl tartrate

Organohalogen flame retardants, particularly brominated aromatics, are popular, effective, low cost, and widely used in the plastics industry. However, an increasing concern about persistence in the environment and potential negative health effects of these materials has generated intense interest in the development of alternatives. Ideally, these should have all the positive attributes of the materials that will be replaced. In addition, it is desirable that the new materials be as “green” as possible, e.g., based on renewable resources and be degradable to nontoxic products in the environment. A series of new, non-halogenated flame retardants based on tartaric acid is being developed. Tartaric acid is a by-product of the wine industry and is readily available locally on an annual basis (Michigan is the thirteenth largest producer of wine in the U.S.). It can be readily converted to the corresponding diethyl ester. This ester may serve as the base for the development of a series of new, non-halogenated flame-retarding agents. The presence of the reactive hydroxyl groups allows the introduction of a variety of phosphorus-containing moieties. For example, treatment of diethyl tartrate with diphenylphosphinyl chloride generates diethyl 2,3-di(diphenylphosphinato)-1,4-butanedioate. This material may serve as a monomer for the preparation of various phosphorus-containing polymers and oligomers via step-growth transesterification. The thermal stability of this compound has been assessed by thermogravimetry.     

Synthesis of vulpinic acids from dimethyl tartrate

A series of vulpinic acids differing by the aryl or heteroaryl groups placed in the ester α-position were prepared by Suzuki-Miyaura cross-coupling involving a common iodide and the corresponding aryl boronates. The preparation of the iodide precursor from (+)-dimethyl l-tartrate required four steps: the esterification of one hydroxyl group, a Dieckmann cyclization allowing the construction of the tetronic acid moiety, a dehydration leading to the installation of the exocyclic double bond and lastly, an N-iodosuccinimide-mediated iodation of the alkene obtained.     

Chiral recognition in association between antimony potassium tartrate and bis(L-alaninate)ethylenediamine cobalt(III) complexes using electrospray ionization mass spectrometry

The chiral recognition of metal complexes by a quick and sensitive mass spectrometric analysis was investigated. The principle is introduction of an external chiral standard compound and detection of the differential association with two optical isomers. Using electrospray ionization mass spectrometry we detected weak intermolecular association between the external chiral anion bis(mu-L-, D-tartrato)-diantimonate(III), [Sb2(L-, D-tart)2]2- and isomeric bis(L-alaninate) ethylenediamine cobalt(III) complex ions, [Co(L-ala)2(en)]+ in acetonitrile/water solution. The difference in the association with optical isomers of the Co complex was measured. The results were interpreted based on a model of intermolecular interaction involving hydrogen bonding. The prospects of the mass spectrometry method for chiral recognition using the external chiral negative ion [Sb2(L-, D-tart)2]2- was discussed.     

Bioaccumulation of Antimony by Chlorella vulgaris and the Association Mode of Antimony in the Cell

The bioaccumulation and excretion of antimony by the freshwater alga Chlorella vulgaris , which had been isolated from an arsenic-polluted environment, are described. When this alga was cultured in a medium containing 50 μg cm⁻³ of antimony(III) for 14 days, it was found that Chlorella vulgaris bioaccumulated antimony at concentrations up to 12 000 μg Sb g⁻¹ dry wt after six days' incubation. The antimony concentration in Chlorella vulgaris decreased from 2570 to 1610 μg Sb g⁻¹ dry wt after the cells were transferred to an antimony-free medium. We found that the excreted antimony consists of 40% antimony(V) and 60% antimony(III). This means that the highly toxic antimony(III) was converted to the less toxic antimony (V) by the living organism. Antimony accumulated in living Chlorella vulgaris cells was solvent-fractionated with chloroform/methanol (2:1), and the extract residue was fractionated with 1% sodium dodecyl sulfate (SDS). Gel-filtration chromatography of the solubilized part showed that antimony was combined with proteins whose molecular weight was around 4×10⁴ in the antimony-accumulated living cells. © 1997 by John Wiley & Sons, Ltd.     

Determination of metoprolol tartrate by capillary isotachophoresis

This paper describes two isotachophoretic methods of metoprolol tartrate (MT) determination in pure and dosage forms. The first method was used for direct analysis where the following electrolyte system was applied: 10 mmol dm⁻³ 3-morpholino-2-hydroxypropanesulfonic acid, 10 mmol dm⁻³ NaCl, 2 % hydroxyethylocelulose as leading (LE) and 10 mmol dm⁻³ glycyl-glycine as terminating (TE) electrolytes. The second method was used for indirect analysis of MT as tartrate ions. In this case, the leading electrolyte consisted of 10 mmol dm⁻³ HCl, β-alanine (BALA), pH 4-5, and the terminating one of 5 mmol dm⁻³ glutamic acid, 10 mmol dm⁻³ β-alanine. Calibration curves were calculated as follows: for system A: y = (0.52 ± 0.05)x − (0.9 ± 0.2) (LOD = 13.0 mg dm⁻³, LOQ = 31.7 mg dm⁻³); and for system B: y = (0.240 +- 0.001)x + (0.18 ± 0.06) (LOD = 1.8 mg dm⁻³, LOQ = 4.4 mg dm⁻³). The isotachophoretic method was compared with the pharmacopoeial one by statistical tests.     

锑胁迫下腐殖质对头花蓼体内锑形态及生化特性影响

锑(Sb)是一种无延展性的有色金属,具有潜在毒性和致癌性,对心血管、呼吸系统和肝脏等都会造成危害。并且,随着近几年锑资源的持续开发,土壤中的Sb污染被广泛关注。腐殖质具有复杂结构并包含有羧基、醇羟基等多种活性官能团,对重金属在土壤中的形态转化、迁移能力以及生物可利用性具有重要影响。头花蓼作为民间常用草药并且也是贵州省特色苗药,在土壤Sb背景值极高的独山锑矿区不仅能大量生长,并且在其体内Sb含量远高于其他未受污染的陆生植物时,仍然可以表现出良好的生长状态。为了探究腐殖质对独山矿区内Sb污染土壤中头花蓼植物有效性的影响。选取贵州省独山县东峰Sb区附近Sb污染土壤与头花蓼种子作为试验样品,通过三种不同腐殖质富里酸、胡敏素、胡敏酸对Sb污染土壤进行30d的培育实验后种植头花蓼。结果表明：(1)腐殖质添加后使得头花蓼叶绿素总量整体呈现上升的趋势,加强了头花蓼光合作用。(2)头花蓼的逆境生理现象表现为：在低添加量下,胡敏素实验组与胡敏酸实验组中丙二醛含量下降,SOD酶活性升高,CAT酶活性下降;说明胡敏素和的胡敏酸在低添加量下能够有效缓解头花蓼所受到的Sb毒害;而高添加量富里酸对头花蓼有一定损害。(3)低添加量的胡敏酸能够有效缓解头花蓼植株所受到的重金属Sb、As、Cd、Cu胁迫。(4)相比于胡敏素和胡敏酸,富里酸更容易促进头花蓼体内残渣态Sb向更活跃的赋存形态转化;胡敏酸对头花蓼中的Sb赋存形态表现出了低浓度活化而高浓度钝化的现象;胡敏素则能够有效降低头花蓼体内Sb活性。