Adsorption of Uranium (VI) Ions on Hydrazinyl Amine and 1,3,4-Thiadiazol-2(3 H)-thion Chelating Resins

Nitrogenous compounds are the most widely used in solid phase extraction due to its low cost, easy convertible to many functional groups. These have large adsorptive capacity toward heavy metal ions as rare earth elements (REEs) and uranium with ability for recovering from low concentrate solutions. Synthesis of resins were carried out by polymerization of acrylonitrile with divinyl benzene as crosslinker. Treatment of the resulted precipitate with hydrazine hydrate in ethanol produce hydrazinyl methyl amine which has high chelating capacity toward uranyl ions. 1,3,4-Thiadiazol-2(3H)-thion derivative was yielded by reaction of hydrazinyl amine with carbon disulfide in methanol. This reaction carried out in the presence of methyl benzoate and dioctyl phthalate as pore producing solvent which used to improve physical properties and adsorptive character of the resins. Optimization on the two resins during loading and elution were carried out using solution with different concentrations. The optimum factors during adsorption and elution were recognized.     

Synthesis and Spectroscopic Characterization of Novel Aryl-Dithiofluorophosphonate Derivatives and X-Ray Studies of [(4-CH3OC6H4)(F)P(S)S−][PH4P+]

Abstract

Potassium and tetraphenylphosphonium salts of novel aryldithiofluorophosphonic acids were synthesized. Lawesson's Reagent was allowed to react with KF in acetonitrile to yield the potassium salt of p-methoxyphenyldithiofluorophosphonic acid. Treatment of the latter with tetraphenylphosphonium chloride resulted in the formation of the tetraphenylphosphonium salt. The structures of the compounds were elucidated by FTIR, ¹H, ¹³C, ¹⁹F, and ³¹P NMR spectroscopy as well as by ESI-mass spectrometry. The molecular and crystal structure of the tetraphenylphosphonium salt, determined by single crystal X-ray diffraction, is also presented.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Preparation,Spectroscopic and Structural Investigations of Spiro Derivatives of Hexachlorocyclotriphosphazatriene

Abstract

Mono-(N₃P₃Cl₄Y₂), bis-(N₃P₃Cl₂Y₄) and tris-spiro derivatives (N₃P₃Y₆) have been prepared with ethylene, 1, 3-propylene and 1,4-butylene glycols (Y₂ = glycol residue). The ¹H NMR spectra of mono- and tris-derivatives are relatively simple; those of the bis- very complex due to the intrinsic asymmetry of the methylene protons. This effect is made use of in studying the replacement pattern of N₃P₃Cl₄ [O (CH₂)₃O] with primary and secondary amines. Homonuclear ¹H decoupling simplifies the spectra and allows an unambiguous distinction to be made between the different isomeric possibilities of the bis amino derivatives N₃P₃Cl₂R₂ [O(CH₂)₃O] where R = amino residue. Primary amines give geminal, secondary amines nongeminal trans-derivatives. The trans-structure of the bis-pyrrolidino derivative has been confirmed by X-ray crystallography.     

Time-Dependent Density Functional Theory Study on Hydrogen and Dihydrogen Bonding in Electronically Excited State of 2-Pyridone–Borane–Trimethylamine Cluster

In this work, the intermolecular dihydrogen and hydrogen bonding interactions in electronically excited states of a 2-pyridone (2PY)–borane–trimethylamine (BTMA) cluster have been theoretically studied using time-dependent density functional theory method. Our computational results show that the S₁ state of 2PY–BTMA cluster is a locally excited state, in which only 2PY moiety is electronically excited. The theoretical infrared (IR) spectra of the 2PY–BTMA cluster demonstrate that the N–H stretching vibrational mode is slightly blue-shifted upon the electronic excitation. Moreover, the computed IR spectrum of the 2PY–BTMA cluster exhibits no carbonyl character due to the extension of the C=O bond length in the S₁ state. However, the N–H bond is shortened slightly upon photoexcitation. At the same time, the H···H and H···O distances are obviously lengthened in the S₁ sate by comparison with those in ground state. In addition, the electron density of the carbonyl oxygen is diminished due to the electronic excitation. Consequently, the proton acceptor ability of carbonyl oxygen is decreased in the electronic excited state. As a result, it is demonstrated that the intermolecular dihydrogen and hydrogen bonds are significantly weakened in the electronically excited state.     

Effect of Nano‐support and Type of Active Metal on Reforming of CH4 with CO2

Two series of Co and Ni based catalysts supported over commercial (ZrO₂, CeO₂, and Al₂O₃) nano supports were investigated for dry reforming of methane. The catalytic activity of both Co and Ni based catalysts were assessed at different reaction temperatures ranging from 500—800 °C; however, for stability the time on stream experiments were conducted at 700 °C for 6 h. Various techniques such as N₂ adsorption‐desorption isotherm, temperature‐programmed reduction (H₂‐TPR), temperature‐programmed desorption (CO₂‐TPD), temperature‐programmed oxidation (TPO), X‐ray diffraction (XRD), thermogravimetric analysis (TGA) were applied for characterization of fresh and spent catalysts. The catalytic activity and stability tests clearly showed that the performance of catalyst is strongly dependent on type of active metal and support. Furthermore, active metal particle size and Lewis basicity are key factors which have significant influence on catalytic performance. The results indicated that Ni supported over nano ZrO₂ exhibited highest activity among all tested catalysts due to its unique properties including thermal stability and reducibility. The minimum carbon deposition and thus relatively stable performance was observed in case of Co‐Al catalyst, since this catalyst has shown highest Lewis basicity.     

Preparation of CTA-based polymer inclusion membrane using calix[4]arene derivative as a carrier for Cr(VI) transport

In this work, the transport of Cr(VI) ions from an aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate buffer at pH 5 through a polymer inclusion membrane (PIM) containing p-tert-butylcalix[4]arene amine derivative as carrier was studied. The Cr(VI) passed through a PIM comprised of cellulose triacetate as a support and 2-NPOE as a plasticizer. The transport efficiency of Cr(VI) was studied under various experimental conditions, such as effect of carrier concentration, acceptor phase pH, type of plasticizer in the membrane, stirring rate and membrane thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), and flux (J). The transport efficiency of Cr(VI) was observed to be 95.07 % after 10 h under optimized conditions. The prepared PIM was characterized with Fourier transform infrared spectroscopy and the atomic force microscopy techniques as well as with contact angle measurements. This is an effective method for the removal of Cr(VI) which is toxic for human body and environment from the waste water.     

Bagley-Torvik型分数阶微分方程和包含非局部积分边值问题

In this article,we consider the Bagley-Torvik type fractional differential equation ~cD~(ν1) l(t)-a~cD~(ν2) l(t) = g(t, l(t)) and differential inclusion ~cD~(ν1) l(t)-a~cD~(ν2) l(t) ∈ G(t, l(t)),t ∈(0, 1) subjecting to l(0) = l_0,and■ ds where 1 ν_1 ≤ 2, 1 ≤ν_2 ν_1,0 ω≤ 1, χ = ν_1-ν_2 0, a, λ′are given constants. By using Leray-Schauder degree theory and fixed point theorems, we prove the existence of solutions. Our results extend the existence theorems for the classical Bagley-Torvik equation and some related models.     

Commutativity for a certain class of rings

We discuss the commutativity of certain rings with unity 1 and one-sideds-unital rings under each of the following conditions:x ^r [x ^s ,y]=±[x,y ^t ]x ⁿ x ^r [x ^s ,y]=±x ⁿ [x,y ^t ]x ^r [x ^s ,y]=±[x,y ^t ]y ^m , andx ^r [x ^s ,y]=±y ^m [x,y ^t ], wherer, n, andm are non-negative integers andt>1,s are positive integers such that eithers, t are relatively prime ors[x,y]=0 implies [x,y]=0. Further, we improve the result of [6, Theorem 3] and reprove several recent results.