Gheorghe Ilia

Divalent metal vinylphosphonate layered materials: compositional variability, structural peculiarities, dehydration behavior, and photoluminescent properties

A family of M-VP (M = Ni, Co, Cd, Mn, Zn, Fe, Cu, Pb; VP = vinylphosphonate) and M-PVP (M = Co, Cd; PVP = phenylvinylphosphonate) materials have been synthesized by hydrothermal methods and characterized by FT-IR, elemental analysis, and thermogravimetric analysis (TGA). Their structures were determined either by single crystal X-ray crystallography or from laboratory X-ray powder diffraction data. The crystal structure of some M-VP and M-PVP materials is two-dimensional (2D) layered, with the organic groups (vinyl or phenylvinyl) protruding into the interlamellar space. However, the Pb-VP and Cu-VP materials show dramatically different structural features. The porous, three-dimensional (3D) structure of Pb-VP contains the Pb center in a pentagonal pyramid. A Cu-VP variant of the common 2D layered structure shows a very peculiar structure. The structure of the material is 2D with the layers based upon three crystallographically distinct Cu atoms; an octahedrally coordinated Cu(2+) atom, a square planar Cu(2+) atom and a Cu(+) atom. The latter has an unusual co-ordination environment as it is 3-coordinated to two oxygen atoms with the third bond across the double bond of the vinyl group. Metal-coordinated water loss was studied by TGA and thermodiffractometry. The rehydration of the anhydrous phases to give the initial phase takes place rapidly for Cd-PVP but it takes several days for Co-PVP. The M-VP materials exhibit variable dehydration-rehydration behavior, with most of them losing crystallinity during the process.

Thermo-oxidative Degradation of Polymers Containing Phosphorus in the Main Chain

In the present study the thermal behavior of some polyphosphonates and polyphosphates was studied. The polymers were synthesized by the inverse phase-transfer catalysis method. The thermal behavior was tested on a Perkin-Elmer DIAMOND device, in a dynamic air atmosphere and with heating rates of 5, 7, 10 and 12 °C min-1. By inspecting the thermogravimetric curves, a remarkable thermal stability up to 200 °C was observed. Between 240 and 380 °C, an endothermic decomposition occurred, with the tendency to a maximum at the end of the process. The end of the thermo-degradation was connected with an oxidative process. A kinetic analysis of the thermogravimetric/differential thermogravimetric results by means of the Friedman, Flynn—Wall—Ozawa, and non-parametric kinetic methods is the basis of discussions on the influence of the molecular architecture on the thermal behavior.

Inhibitory effects of some synthetic monoethanolamine salts of para-substituted benzoic acids and corresponding benzoic acids on cucumber seed germination

Abstract Benzoates and particularly, benzoic acids are known biologically for their effects in the regulation of seed germination. A series of monoethanolamine salts of para-substituted benzoic acids (MEASPBAs), the corresponding acids (BAs) and monoethanolamine (MEA) were tested at different concentrations, on Cucumis sativus L. germination in order to assess their biological activity. The correlation between the effects of different substituents of these salts and the corresponding acids with germination rate, root and shoot length, fresh and dry biomass, soluble protein content, isocitrate lyase (ICL, EC 4.1.3.1) and catalase (CAT, EC 1.11.1.6.) activity, was evaluated. Data showed that p-OH and p-CH3 substituents had a lower inhibitory effect compared to the halogenated substituents. Moreover, the inhibition of root and shoot lengths and the dramatic decrease of fresh biomass for halogenated (p-Cl, p-Br, p-I) MEASPBAs and BAs followed the increase of the atomic size of the substituent.

Solvent and catalyst-free synthesis of polyphosphates

Direct, efficient, solvent and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas–liquid interfacial polycondensation between alkyl(aryl)phosphoric dichlorides and aromatic diols. The polyphosphates were characterized by IR, 1H NMR, inherent viscosity, thermal analysis, X-ray diffractions and molar mass. Yields in the range 75–90% and inherent viscosities in the range 0.24–0.45 dl g−1 were obtained. Polyphosphates were stable up to 170–250 °C, depending on phosphoric dichloride type. The X-ray diffraction patterns revealed that almost all the polymers were amorphous.

Use of styrene–divinylbenzene grafted with aminoethylaminomethyl groups and various ionic liquids in the removal process of thallium and strontium

Abstract This work reports the adsorption of thallium and strontium from aqueous solutions onto styrene-divinylbenzene grafted with aminoethylaminomethyl groups which was impregnated with various ionic liquids [trihexyltetradecylphosphonium chloride ionic liquid – (Cyphos IL-101); 1-octyl-3-methylimidazolium tetrafluoroborate – (OmimBF4) and 1-butyl-3-methylimidazolium hexafluorophosphate – (BmimPF6)]. The impregnation of the solid support with the studied ionic liquids was realized through ultrasonication method. The obtained impregnated materials have been subjected to Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Their adsorption performance in the removal process of thallium and strontium from aqueous solutions was studied as a function of the initial concentration of metal ions. Adsorption isotherms like Langmuir, Freundlich, Dubinin–Radushkevich (D–R) and Temkin were used to analyze the equilibrium data at different concentrations. The studied materials showed a better adsorption performance in the removal process of strontium ions compared to the adsorption performance obtained in case of thallium ions removal process. From the studied ionic liquids, (OmimBF4) presented the most efficient performance for the removal of the studied metal ions.

Synthesis of new phosphorus-containing (co)polyesters using solid-liquid phase transfer catalysis and product characterization.

This paper is directed towards the development of safe, and thermally stable solid polymer electrolytes. Linear phosphorus-containing (co)polyesters are described, including their synthesis, thermal analysis, conductivity, and non-flammability. Polycondensation of phenylphosphonic dichloride (PPD) with poly(ethylene glycol) (PEG 12000) with and without bisphenol A (BA) was carried out using solid-liquid phase transfer catalysis. Potassium phosphate is used as base. Yields in the range of 85.0–88.0%, and inherent viscosities in the range of 0.32–0.58 dL/g were obtained. The polymers were characterized by gel permeation chromatography, FT-IR, 1H- and 31P-NMR spectroscopy and thermal analysis. Their flammability was investigated by measuring limiting oxygen index values. The polymers are flame retardants and begin to lose weight in the 190 °C–231 °C range. Solid phosphorus- containing (co)polyesters were complexed with lithium triflate and the resulting ionic conductivity was determined. Conductivities in the range of 10−7–10−8 S cm−1 were obtained.

Polymers containing phosphorus groups and polyethers: from synthesis to application

BackgroundPhosphorus-containing high performance polymers have aroused wide interest, mainly due to good mechanical properties and their excellent fire resistance. The flexibility of synthetic polyphosphoesters allows the development of polymers in order to obtain solid polymer electrolytes for rechargeable lithium batteries based on solid films with superior fire resistance.ResultsNovel linear Phosphonate-PEG polymers were synthesized by solution polycondensation of 4-chlorophenyldichlorophosphonate as a linking agent and poly(ethylene glycol)s with different molecular weights in the presence of triethylamine or 1-methylimidazole as acid scavenger. The yields were between 54% and 88% and inherent viscosity between 0.18-0.48 dl/g. Molar masses, Mn were about 26300 g/mol for polyphosphonates with PEG 2000 and 4600 g/mol for polyphosphonates with PEG 200. The LOI values for these polymers and membranes are in the range of 26–29. The membranes based on polyphosphonate with PEG 200 and 2000 showed conductivity between 6 × 10-8 S.cm-1 and 6 × 10-7 S.cm-1 at room temperature and total ionic transference number between 0.87- 0.96. The evolution of conductivity vs. temperature is linear.Conclusions1-methylimidazole was found to be better HCl scavenger than triethylamine, and allowed higher yields and more eco-friendly synthesis of the Phosphonate-PEG polymers for SPE. These polymers and membranes based on these polymers showed good LOI values and indicate an improvement of the safety of lithium batteries. The membranes present conductivities around 6 × 10-7 S.cm-1at room temperature and total ionic transference number is higher for membranes based on polymers with high EG unit content. Best results yield 88%, inherent viscosities 0.48 dl/g and Mn 26000 were obtained with 1-methylimidazole and PEG 2000. These membranes based on these polymers showed good LOI values (in the range 26-29%) and indicate an improvement of the safety of lithium batteries.

Organic solvent-free synthesis of phosphorus- containing polymers*

Direct, efficient, organic solvent- and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas-liquid interfacial polycondensation between arylphosphoric dichlorides and bisphenol A. The polyphosphates were characterized by IR, 1H NMR, 31P NMR, inherent viscosity, thermal analysis, and molar mass. Yields in the range 70-90 % and inherent viscosities in the range 0.30-0.40 dl/g were obtained. The thermal stability of the polyphosphates was investigated by using thermogravimetry.

Mixed Quaternary Ammonium and Phosphonium Salts Bound to Macromolecular Supports for Removal Bacteria from Water

This paper deals with synthesis and characterization of mixed quaternary ammonium and phosphonium salts grafted on macromolecular supports by polymer-analogous trans-quaternization reactions. The degrees of functionalization with quaternary mixed ammonium and phosphonium groups are relatively high, ranging from 0.09 to 1.285 mmoles of functional groups/gram of copolymer, ensuring a sufficient concentration of active centers per unit mass of copolymer and being well suited for application as antibacterial agents.

Synthesis of Mixed Alkylphosphites and Alkylphosphates

Some mixed phosphites having two different alkyl chain were obtained as forerunners for mixed phosphates Mixed dialkyl phosphates were obtained in good yields (40-80%) by phase transfer catalysis in liquid-liquid sistem, starting from different dialkyl phosphites and aliphatic alcohols. The reaction conditions were optimized in order to obtain good yields in phosphites and phosphates respectively. Compounds were analyzed by IR, P 31 -NMR.