Anionic Graft Polymerisation of Styrene from Polyisoprene. Dependence of Grafting Efficiency on Polyisoprene Structure

Styrene was grafted from polyisoprene forming poly(isoprene-g-styrene) graft polymers. N,N,N',N'-Tetramethylene diamine and s-butyllithium were used to create active centres on the polyisoprene backbone in cyclohexane under anionic living polymerisation conditions. The stereoregularity of polyisoprene is shown to influence the grafting efficiency. Addition of small amounts of tetrahydrofuran increased grafting efficiency and decreased polydispersity of the graft polymers obtained. Polystyrene branches are shown to be syndiotactic rich.     

Synthese und Eigenschaften eines chelatbildenden Austauschers mit N,N′-bis-(2-hydroxybenzyl)-ethylendiamin als Ankergruppe auf der Basis von Polystyrol

The synthesis of a new polystyrene exchanger contaning N,N'-bis-(2-hydroxybenzyl)-ethylenediamine as anchor group is described. The anchor group is obtained by reaction of salicylaldehyde with ethylenediamine to N,N'-ethylene-bis-(salicyldiamine) = “Salen” and hydration of “Salen”. Polystyrene is nitrated, reduced, diazotated and coupled with N,N'-bis-(2-hydroxybenzyl)-ethylenediamine. The exchanger is characterized by determination of its anchor group content and its capacity, by measuring the rate of exchange and by determination of the distribution coefficients for Au³⁺, Pd²⁺, Pt⁴⁺, Cu²⁺, and Ni²⁺ ions.     

Synthesis and Properties of Two Amino Carboxylic Acid Gemini Surfactants

The number of hydrophilic and hydrophobic groups of a surfactant has a great influence on its property. Two Gemini surfactants, N,N″‘-didodecyl-N,N',N″,N″‘-tetrapropionate triethylenetetramine and N,N'-didodecyl-N,N'-dipropionate ethylenediamine (referred as DTPTT and DDPED), were prepared by Michael addition reaction of the didodecyl secondary amines with methyl acrylate. The didodecyl secondary amines were synthesized by nucleophilic substitution reaction of triethylenetetramine or ethylenediamine with bromododecane. The DTPTT and DDPED surfactants were characterized by mass spectrometry and proton nuclear magnetic resonance spectrometry. The surface activities of the DTPTT and DDPED aqueous solutions were studied by surface tension measurements. The surface tension and critical micelle concentration (cmc) of DDPED is smaller than that of DTPTT. The DDPED can reduce the surface tension of water to approximate 34 mN m⁻¹ at concentration levels of 10⁻⁵ mol L⁻¹. The aggregation behavior of the DTPTT and DDPED aqueous solution were studied by dynamic light scattering and transmission electron microscopy. Both surfactants can form spherical vesicles at a solution of about 3–5 times cmc of the Gemini surfactants. The foam property was determined by nitrogen blowing method. The DTPTT has relatively good foaming ability and DDPED has excellent foam stability. The foam volume of DDPED barely change within 1000s. The emulsion stability of the Gemini surfactants was determined by separation time of water from the emulsion. The emulsion stability of DDPED is equivalent to Tween 80. The DDPED Gemini surfactant with two hydrophilic carboxylic groups has better surface activity, foam stability, and can be used as an O/W emulsifier.     

Electroinitiated polymerization of some new monomers with schiff's base structure and pyrrole moieties

Pyrrole-2-aldehyd azine, N,N'-bis(2-pyrrolylmethylene)-1,4-diaminobenzene and N,N'-bis(2-pyrrolylmethylene)-4,4′-diaminobiphenyl were polymerized by electro-chemical precipitating oxidation reaction in 1,2-dichloroethane and acetonitrile, respectively, in the presence of electrolytes like tetrabutylammonium perchlorate, tetrabutylammonium tetrafluoroborate and sodium p-toluene sulfonate. The doped resulted polymers were characterized by elemental analysis, IR spectroscopy and thermal analysis.     

Synthesis,characterization, and kinetic study on the thermal decomposition of polyamidoethers

Some new polyamidoethers have been synthesized by condensation reaction of N,N'-dichloroacetyl-1,4-phenylene-diamine with bisphenols (4,4'-isopropylidenediphenol, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, and 4,4'-dihydroxybiphenyl) in N-methylpyrrolidone medium using DB-24-Crown-8 as a phase-transfer catalyst. The structure of these polymers has been characterized by infrared (i.r.) and ¹H nuclear magnetic resonance (NMR) spectroscopy. Kinetic method of thermal decomposition of these polymers and their 2% mixture with polyvinylchloride (PVC) has been studied.     

LIQUID-LIQUID EXTRACTION STUDIES OF METAL IONS WITH DIAZACROWN AND STRUCTURE ANALOGOUS OPEN-CHAIN COMPOUNOS

1,10-diaze [8]crown-6, their N,N'-dibutyl- and dioctyl-substituted derivatives and the structure analogous open-chein tetreoxedieza slkanee have been synthesized in order to examine the extraction properties for Na⁺, K⁺, Sr²⁺ and Hg²⁺. It wes found, that the extraction of strontium, potassium and sodium picratee with azacrown compounds ie much higher than that with open-chein oxaaze alkanes. 1,10-diaze [18] erown-6 has a good selectivity for the extraction of Sr²⁺ over K⁺ and Na in alkaline solution. In the case of Sr²⁺ the diffarencea between tha various azacrown compounds are email, whereea in the caee of K⁺ and Na the substituted derivativee are better extractante. Theserssulte correspond qualitativsly with tha order of stebility conetantB in protic solvsnts. The extrectebility of N,N'-dioctyl-l, 10-dieze[18]crown-6 for HgCl₂ is very high. Contrerv to the order of stability conetants the uneubetituted conpound do not extract mercury under the choeen experimental condition*. The extraction power of open-chain conpounde ie aleo high and strong Influenced by the alkyl eubatltuente at the nitrogen donor stons,     

An efficient method for synthesis of some heterocyclic compounds containing 3-iminoisatin and 1,2,4-triazole using Fe3O4 magnetic nanoparticles

1,2,4-triazole derivatives were prepared by reaction of thiocarbohydrazide and some esters in 60% ethanol. Condensation of 1,2,4-triazole derivatives with isatin gave Schiff bases of 3-iminoisatin derivatives. Reaction of malonic or succinic acid dihydrazide with isatin lead to formation of N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)-malonamide 8a and N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)succinamide 8b in good yields under mild reaction conditions. These reactions are catalyzed by Fe₃O₄ MNPs. The chemical structures were confirmed by Fourier transform-infrared, ¹H-NMR, ¹³C-NMR, gas chromatography-mass spectrometry spectroscopy, and elemental analysis.     

Activated polymers. II: Synthesis and exchange reactions of biologically active poly(8-acryloxyquinoline)

The monomer 8-acryloxyquinoline (8-AQ) was prepared through the reaction of 8-hydroxyquinoline with either acryloyl chloride or acrylic acid in the presence of triethylamine or N,N-dicyclohexylcarbodiimide, respectively . The resulting monomer was polymerized by free radical polymerization using dimethylformamide (DMF) as a solvent and 2,2^'-azobisisobutyronitrile (AIBN) as an initiator. The reactions of the resulting polymers with hydroxyl and amino compounds have been studied. The polymers were characterized by IR and ¹HNMR spectroscopy. Some of the synthesized polymers were tested for their antimicrobial activity against bacteria and fungi. Generally, all the polymers were effective against the tested microorganisms, but their growth-inhibition effects varied.     

Cyclization dynamics of polymers: 7. Applications of the pyrene excimer technique to the internal dynamics of poly(dimethylsiloxane) chains

Poly(dimethylsiloxane) (PDMS) polymers end-capped on both ends with pyrene chromophores have been synthesized. Rate constants for end-to-end cyclization 〈 k₁ 〉 have been determined for dilute solutions of these polymers in toluene solution using a combination of fluorescence decay and steady-state fluorescence measurements. While precise values of the critical exponent for the chain length (N¯) dependence of 〈 k₁ 〉 are not yet available, these results are consistent with the N¯^{? 3/2} dependence predicted by Wilemski-Fixman theory. PDMS chains cyclize somewhat more than two times faster than polystyrene chains of the same length in solvents of similar solvating power and viscosity. These results provide strong support for similar predictions made several years ago by Perico and Cuniberti, who used intrinsic viscosity data to parametrize the Rouse-Zimm model for analysis of polymer cyclization dynamics.     

Unvernetzte epoxid-amin-additionspolymere, 25. Oligoether-diamine als elastifizierende comonomere für lineare epoxid-amin-additionspolymere

N,N'-Dibenzyl-3,6-dioxaoctane-diamine-1,8 and three analogous secondary diamines (EDA) all of which have long chain aliphatic ether groups were prepared and reacted with diglycidylether of bisphenol-A (DGEBA) to give well defined linear epoxide-amine addition polymers. Due to the flexible spacer in the amine component, the glass transition temperatures (T_g) of DGEBA/EDA copolymers decrease to 9–23°C. Likewise T_g's of DGEBA/polyamine networks are significantly lowered by copolymerization with EDA (T_g = 25 –100°C). Such flexible copolymers may be used as strain free optical adhesives or as the soft component in polymer blends and interpenetrating networks. Thermodynamic and kinetic polyreaction parameters were measured by DSC. In excellent correspondence with experiments, data have been calculated using a refined reaction model. This includes both noncatalyzed and catalyzed parallel reactions. The latter ones are activated by NH···HO complexation resulting from growing amounts of HO groups in the addition product.     

Influence of cultivars and nitrogen rates on the residual effects of potassium applications to preceding cotton on maize

The long-term residual effects of K application rates and cultivars for preceding cotton (Gossypium hirsutum L.) on subsequent maize (Zea mays L.) and the influence of N rates applied to preceding cotton and to maize on the residual K effects were examined on maize under no-tillage in the United States. Two field experiments were conducted on a no-till Loring silt loam at Jackson, TN during 1995–2008 with N rates (90 and 179 kg ha^?1) × K rates (28, 56, and 84 kg ha^?1) and cotton cultivars (determinate and indeterminate) × K rates (56 and 112 kg ha^?1) as the treatments, respectively, in the preceding cotton seasons. Maize was planted under no-tillage on the preceding cotton experiments without any K application during 2009 through 2011. The residual effects of K rates applied to preceding cotton on soil K levels were significantly influenced by the N rates applied to preceding cotton and to maize when the data were combined from 2008 to 2011. Relative to the standard N management practices of 168 kg N ha^?1 for maize and 90 kg N ha^?1 for preceding cotton, the higher N application rate 269 kg N ha^?1 to maize and 179 kg N ha^?1 to preceding cotton reduced the residual effects of K rates on soil K. However, cultivar for preceding cotton did not affect the residual effects of K fertilizer on soil K fertility, leaf K nutrition, plant growth, or grain yield of subsequent maize on a high K field.     

Soil mineral nitrogen availability predicted by herbage yield and disease resistance in red clover (<Emphasis Type="Italic">Trifolium pratense</Emphasis>) cropping

Nitrogen (N) is the most limiting nutrient in crop production. Legumes such as red clover can provide N through biofixation, but securing nitrogen in soil for subsequent crop production must also be considered. Variety selection and management in red clover cropping can influence soil mineral nitrogen (SMN) availability. A field trial to investigate this was conducted with six varieties, under one and two cut management, over 2 years. Dry matter (DM) and N yield, Sclerotinia resistance and SMN availability were assessed. Low DM and N yields (1.6–2.4 t DM ha^?1 and 54–83 kg N ha^?1) in the first year of cultivation allowed ~?40 kg N ha^?1 to become available, but high DM and N yields (10.2–14.6 t DM ha^?1 and 405–544 kg N ha^?1) allowed ~?20 kg N ha^?1 to become available. Wetter weather in 2015 caused significantly more SMN losses than 2016 (20 kg N ha^?1 in 2015 and 5 kg N ha^?1 in 2016). The varieties Amos, Maro and Milvus lost significantly more SMN in the winter period, which may have been caused by more severe infection of Sclerotinia (these varieties were 50–80% more severely infected other varieties). Varietal effect was non-significant for winter losses in 2016, where no significant varietal differences in Sclerotinia infection were observed. 1 cut made ~?41 kg N ha^?1 available in the growing season of 2015, whilst 2 cut made significantly less (37 kg N ha^?1). Cutting was non-significant in 2016 but 1 cut was less susceptible to losses in the winter period. Cutting in 2015 did not significantly affect herbage DM and N yields in the first or second cut of 2016.     

Potentiality of Nonorganophosphorus Extractant in Chemical Separations of Actinides

Abstract

To limit the amounts of radioactive wastes coming from actinide separations by solvent—extraction, completely incinerable extractants are desirable. This paper deals with the prospects offered by N, N-dialkylamide.s, as alternatives to TBP for irradiated nuclear fuels reprocessing and by N, N'-tetraalkyl 2-alkylpro-pane diamides as actinide extractants from radioactive wastes solutions. The selection of N. N'-dialkylamides based on the solubility of the nitrato-uranyl amide complexes in aliphatic hydrocarbons is presented. The extraction chemistry of the main metallic ions present in irradiated nuclear fuels nitrate solutions is discussed as well as the hydrolysis and radio-lysis of these extractants. Results of a bench scale test for a first reprocessing cycle shows the reason for interest in the N, N-dialkylamides as substitutes for TBP. The extraction of the main metallic species contained in actinide wastes by N, N'-tetraalkylpropane diamide or by N, N'-tetraalkyl, 2-alkylpropane diamide is presented. The results show that these diamides present good prospects, for removing the actinides contained in various wastes solutions.     

Synthesis of N,N'-diallylmalonamide and its copolymer gels with acrylic acid and acrylamide

N,N'-diallylmalonamide (DAM) has been prepared via classical aminolysis of diethyl malonate with allylamine. Its structure was confirmed by elementary microanalysis as well as ¹H NMR and FT-IR spectroscopy. The new diallyl monomer is water-soluble and able to copolymerize radically with water-soluble monomers, such as acrylamide and acrylic acid, to give transparent hydrogels by using K₂S₂O₈ as initiator. Homopolymerization of DAM yields clear hydrogels with high swelling ability.     

Studies on the Use of N,N,N´,N´-Tetra(2-ethylhexyl) Diglycolamide (TEHDGA) for Actinide Partitioning. I: Investigation on Third-Phase Formation and Extraction Behavior

Abstract

Diglycolamides have emerged as an interesting class of extractants for actinide partitioning from high-level waste (HLW). N,N,N´,N´-tetraoctyl diglycolamide (TODGA) has been extensively studied for lanthanide-actinide co-extraction behavior. The present work deals with a branched isomer of TODGA, that is, N,N,N´,N´-tetra(2-ethylhexyl) diglycolamide (TEHDGA). TEHDGA was studied for the extraction of ²⁴¹Am and third-phase formation. The effect of using different phase modifiers on the prevention of the formation of a third phase during nitric acid extraction by TEHDGA along with the acid uptake behavior by TEHDGA in the presence of the modifiers was studied. The modifiers used for this purpose were di(n-hexyl)octanamide (DHOA), isodecanol, and n-decanol. The effect of the modifiers on the uptake of ²⁴¹Am as a function of acid concentration and as a function of modifier concentration was also examined. DHOA was found to be a suitable modifier, in spite of its high acid uptake. The uptake of lanthanides Ce, La, Eu, Gd, and Nd and elements such as Fe, Ni, Mn, Mo, Ru, Sr, and Cs with DHOA-modified TEHDGA–n-dodecane solvent systems were investigated. The results obtained indicated that, while DHOA-modified TEHDGA/n-dodecane extracted lanthanides and actinides, it did not show any significant uptake of other elements. Thus, the TEHDGA-DHOA/n-dodecane solvent system can be used effectively for the partitioning of lanthanides and actinides from HLW.     

PART 3. THE EXTRACTION OF Co2+, Ni2+, Cu2+ AND Zn2+ USING NOVEL DITERTIARY-AMINEEXTRACTANTS

The syntheses of N-N-octyl-2-2'-pyridylimidazole and N,N'-di-n-octyl-(a)-aminopicoline are presented. Their extraction properties are compared with that of an aliphatic diamine N,N,N',N'-tetraoctylethylene-diamine. The reagents, dissolved in chloroform, were used to extract divalent cobalt, nickel, copper and zinc from aqueous chloride medium. Two extraction mechanisms are postulated for the extraction of these metals, and extraction data are discussed in terms of these postulates.

Extraction of the copper(II) ion at low pH values with amines is best effected by the inclusion of aromatic nitrogen atoms into a diamine extractant.     

Antimony polymers,part 2. Physical,chemical and thermal properties

Three antimony-containing polymers (P₁, P₂, P₃) were synthesized by reacting triphenyl antimony dinitrate with bisphenol A (P₁), with tetrabromobisphenol A (P₂) and with N,N′-bis(4-hydroxybenzylidene)-oxydianiline (P₃). Solubility, density, chemical and thermal stability of these antimony polymers have been evaluated. The polymers are only soluble in dipolar aprotic solvents like dimethyl sulfoxide, dimethylformamide, dimethylacetamide, etc., and have relatively high densities (1.2–1.8 g cm^–3). The solubility parameters (δ) and chemical stability of the polymers were studied in different chemical environments. The thermal properties of the polymers have been studied by thermogravimetric analysis, differential thermal analysis and isothermal gravimetric analysis.     

Actinide Partitioning with a Modified TODGA Solvent: Counter-Current Extraction Studies with Simulated High Level Waste

Actinide partitioning studies with improved N,N,N',N'-tetraoctyl diglycolamide (TODGA) solvent (0.05 M TODGA + 5% iso-decanol in n-dodecane) has been explored in order to achieve better decontamination from fission products. The distribution behavior of various metal ions, viz. Am, Pu, U, Eu, Sr, Pd, Cs, Tc, Fe, and Mo with improved TODGA solvent was investigated. Lower concentration of TODGA (0.05 M as compared to previously proposed 0.1 M or 0.2 M) exhibited required extraction properties for actinide partitioning from pressurized heavy water reactor high level waste (PHWR-HLW). Counter-current extraction studies with simulated PHWR-HLW spiked with different radio-tracers (viz. ²⁴¹Am, ¹⁵²Eu, ¹³⁷Cs, ^85,89Sr, ⁵⁹Fe, ¹⁰⁶Ru, ¹⁰⁹Pd, ⁹⁵Zr, and ⁹⁹Mo) suggested that > 99.9% of the trivalent actinides and lanthanides could be extracted in six stages and stripped in four stages. The decontamination factor for various fission products with respect to Am was: 3918 (Cs), 2990 (Sr), 1150 (Zr), 1407 (Ru), 1185 (Pd), and 3250 (Mo). The counter-current extraction studies with the irradiated solvent (500 kGy) reflected a significant amount of Mo extraction.     

Radiative and Nonradiative Decay of Electronically Excited HNF and DNF

Decay lifetimes for a range of HNF and DNF levels in their excited à ²A' electronic states, in specific K' stacks and in some cases in individual N' rotational levels, are reported. Above a threshold energy, these lifetimes are found to drop, in a K'- and N'-dependent way, below the extrapolated purely radiative lifetimes. This reduction in lifetime is ascribed to the onset of nonradiative, predissociative decay. Lifetimes for individual N' rotational levels in the HNF(òA') (0,4,0) and DNF(òA') (0,6,0) vibrational manifolds are also reported. These are found to fluctuate in a seemingly random manner vs. N', reflecting the variation of the coupling to the dissociation continuum. The implications of these results and, from other experiments, the direct observation of NH(X³Σ⁻) and ND(X³Σ⁻) photofragments for the dynamics of the nonradiative decay of electronically excited HNF and DNF are discussed.     

Land management between crops affects soil inorganic nitrogen balance in a tropical rice system

Sustainable production of lowland rice (Oryza sativa L.) requires minimising undesirable soil nitrogen (N) losses via nitrate (NO₃ ^?) leaching and denitrification. However, information is limited on the N transformations that occur between rice crops (fallow and land preparation), which control indigenous N availability for the subsequent crop. In order to redress this knowledge gap, changes in NO₃ ^? isotopic composition (δ¹⁵N and δ¹⁸O) in soil and water were measured from harvest through fallow, land preparation, and crop establishment in a 7 year old field trial in the Philippines. During the period between rice crops, plots were maintained either, continuously flooded, dry, or alternately wet and dry from rainfall. Plots were split with addition or removal of residue from the previous rice crop. No N fertilizer was applied during the experimental period. Nitrogen accumulated during the fallow (20 kg NH₄ ⁺–N ha^?1 in flooded treatments and 10 kg NO₃ ^?–N ha^?1 in treatments with drying), but did not influence N availability for the subsequent crop. Nitrate isotope fractionation patterns indicated that denitrification drove this homogenisation: during land preparation ~50 % of inorganic N in the soil (top 10 cm) was denitrified, and by 2 weeks after transplanting this increased to >80 % of inorganic N, regardless of fallow management. The 17 days between fallow and crop establishment controlled not only N attenuation (3–7 kg NO₃ ^?–N ha^?1 denitrified), but also N inputs (3–14 kg NO₃ ^?–N ha^?1 from nitrification), meaning denitrification was dependent on soil nitrification rates. While crop residue incorporation delayed the timing of N attenuation, it ultimately did not impact indigenous N supply. By measuring NO₃ ^? isotopic composition over depth and time, this study provides unique in situ measurements of the pivotal role of land preparation in determining paddy soil indigenous N supply.