Phase diagram for the hexane-acetonitrile-tri-<Emphasis Type="Italic">n</Emphasis>-butyl phosphate-solvated thorium(IV) nitrate ternary liquid system

Phase diagrams of the hexane-acetonitrile-[Th(NO₃)₄(TBP)₂] liquid ternary system were studied at various temperatures. The system consists of two pairs of incompletely miscible liquids: hexane-acetonitrile and [Th(NO₃)₄(TBP)₂]-hexane. The two-liquid field in the [Th(NO₃)₄(TBP)₂]-hexane system decreases with increasing temperature; the upper critical solution temperature T _cr = 337.85 ± 0.25 K. The temperature effect on the immiscibility field in the hexane-acetonitrile system is insignificant. The title ternary liquid system is characterized by two homogeneous liquid fields and one two-phase liquid field at T < 338 K. One phase is depleted of acetonitrile and contains variable proportions of [Th(NO₃)₄(TBP)₂] and hexane; the other contains variable proportions of acetonitrile and [Th(NO₃)₄(TBP)₂] and a small proportion of hexane. With rising temperature, the two-phase field narrows and deforms, whereas the homogeneous liquid fields expand. At T > 338 K, the system transforms into a ternary liquid system with one pair of incompletely miscible liquids (hexane-acetonitrile).     

W/O、O/W型卵磷脂乳状液对CaCO3晶型的影响

Ｗ／Ｏ、Ｏ／Ｗ型卵磷脂乳状液对ＣａＣＯ３晶型的影响姚松年＊缪炜童华张操墨熊海涛（武汉大学分析测试科学系，武汉４３００７２）关键词：卵磷脂乳状液ＣａＣＯ３碳酸钙可以方解石、霰石、球霰石、胶状碳酸钙等形态存在且依次稳定性降低。珍珠是生物矿化产物，除氨基酸...     

Phase diagram for the hexane-dimethylformamide-neodymium(III) nitrate tri-n-butyl phosphate solvate liquid ternary system at various temperatures

Phase diagrams of the hexane-dimethylformamide-[Nd(NO₃)₃(TBP)₃] ternary liquid system at various temperatures were studied. The system consists of two pairs of incompletely miscible liquids: hexane-dimethylformamide (DMF) and [Nd(NO₃)₃(TBP)₃]-hexane. The liquid-liquid phase separation region in the [Nd(NO₃)₃(TBP)₃]-hexane system narrows with rising temperature; the upper critical solution T _cr = (316.15 ± 0.25) K. Temperature insignificantly influences the immiscibility region in the hexane-DMF system. The ternary liquid system has two homogeneous fields and one two-phase liquid solution field at T < 316 K. One phase is depleted of DMF and contains variable [Nd(NO₃)₃(TBP)₃] and hexane proportions; the other contains variable DMF and [Nd(NO₃)₃(TBP)₃] proportions and small hexane percentages. The two-phase region narrows and deforms with rising temperature, whereas the homogeneous regions expand. At T > 337 K, the system transforms to a ternary liquid system with one pair of incompletely miscible liquids (hexane-DMF).     

Nd(OR)3-mClm-AlEt3 catalyst system in the polymerization of butadiene: I. The general feature of polymerization

Homopolymerization of butadiene has been carried out with a new series of binary catalyst system Nd(OR)_3-mG_m-AlEt₃. The catalytic activity as well as the microstructure of the resulting polymer have been studied. The results indicate that the stereospecificity of the polybutadiene obtained with these binary catalyst system (when m = 2) is similar to that prepared with ternary system Nd(OR)₃-Al₂Et₃Cl₃-AlEt₃, yet the catalytic activity of the former is somewhat higher. Thus possibly, the present simpler binary system is preferable to the ternary system when applied to the polymerization of butadiene.     

Electronic structure of random copolymers

The electronic structure of random copolymers (RCP) is theoretically investigated by the single-site coherent potential approximation. The results are also compared with those by the band calculation for the corresponding ordered system. In the A_{1 –x} B _x binary RCP, a strong reduction in the system band gap (E _g(A_1–x B _x )) is found in the dilute B region when the system has the relation ofE _g(A)>E _g(B). This dependence is caused by the asymmetric quenching in the density-of-states (DOS) singularity at the band-edge states. The gap-opening mechanism and the asymmetric quenching are discussed by focusing on the role of the spatial dimension on the electronic structure of the random system, and the theoretical treatment is finally applied to the calculation of the joint DOS for the Si-Ge RCP system.     

Oxidation of Cycloalkanes by Hydrogen Peroxide in a Biomimetic Iron Porphyrin System

The kinetics of cyclohexane and cyclopentane oxidation by hydrogen peroxide catalyzed by iron porphyrins (FeTPP and FeTDCPP) in acetonitrile solutions is studied at room temperature by analyzing product accumulation with the GLC method. The effects of various additives (acetic acid, imidazole, and hydroquinone) on the substrate selectivity of the competitive oxidation of C₆H₁₂ and C₅H₁₀ are studied. In the FeTDCPP/H₂O₂/O₂/AcOH/CH₃CN system, cyclohexane is oxidized to the corresponding alcohol, ketone, and hydroperoxide. The fraction of the product (hydroperoxide) formed by the radical mechanism is 20–30%. The alcohol and ketone are formed by the molecular pathway in a ratio of (6–7) : 1. Kinetic parameters of cycloalkane oxidation are compared in a biomimetic system with hydrogen peroxide (the shunt system) and the system based on dioxygen with electron and proton donors. The latter system modeled cytochrome P-450. It is shown that active species are the same in both systems. The kinetic scheme of the alkane oxidation process is proposed for the shunt system.     

Phase equilibrium in the system RbCl-EuCl<Subscript>3</Subscript>-HCl(13.44, 22.75%)-H<Subscript>2</Subscript>O at 298.15 K

Solubility of the quaternary system RbCl-EuCl₃-HCl(13.44, 22.75%)-H₂O at 298.15 K was determined and corresponding equilibrium diagrams were constructed. The quaternary system is simple, and consists of two equilibrium solid phases RbCl and EuCl₃ · 6H₂O. The composition of double saturation point (average) is 13.29% HCl, 16.18% RbCl, and 18.72% EuCl₃ for the RbCl-EuCl₃-HCl(13.44%)-H₂O quaternary system, and 22.44% HCl, 15.59% RbCl, and 6.26% EuCl₃ for the RbCl-EuCl₃-HCl (22.75%)-H₂O quaternary system.     

Phase equilibria in ternary liquid systems containing solvates of lutetium(III) and uranyl(VI) nitrates with tri-n-butyl phosphate and tetradecane at various temperatures

The phase diagram has been studied for the ternary liquid system (TLS) [Lu(NO₃)₃(TBP)₃]-[UO₂(NO₃)₂(TBP)₂]-tetradecane at T = 298.15–333.15 K. There are fields of homogeneous and two-phase solutions in the system. One phase (phase I) is enriched in [Lu(NO₃)₃(TBP)₃] and [UO₂(NO₃)₂(TBP)₂]; the other (phase II) is enriched in tetradecane. Critical compositions in the system depend on temperature. [UO₂(NO₃)₂(TBP)₂] tends to be distributed to phase I, despite the fact that the binary system [UO₂(NO₃)₂(TBP)₂[-tetradecane is a single phase at all temperatures studied.     

Phase diagram for the hexane-acetonitrile-tri-n-butyl phosphate-solvated neodymium(III) nitrate ternary liquid system

Phase diagrams of the hexane-acetonitrile-[Nd(NO₃)₃(TBP)₃] liquid ternary system were studied at various temperatures. The system consists of two pairs of incompletely miscible liquids: hexane-acetonitrile and [Nd(NO₃)₃(TBP)₃]-hexane. The two-liquid field in the [Nd(NO₃)₃(TBP)₃]-hexane system decreases with increasing temperature; the upper critical solution temperature T _cr = 316.15 ± 0.25 K. The temperature effect on the immiscibility field in the hexane-acetonitrile system is insignificant. The title ternary liquid system is characterized by two homogeneous liquid fields and one two-phase liquid field at T < 316 K. One phase is depleted of acetonitrile and contains variable proportions of [Nd(NO₃)₃(TBP)₃] and hexane; the other contains variable proportions of acetonitrile and [Nd(NO₃)₃(TBP)₃] and a small proportion of hexane. With rising temperature, the two-phase field narrows and deforms, whereas the homogeneous liquid fields expand. At T > 337 K, the system transforms into a ternary liquid system with one pair of incompletely miscible liquids (hexane-acetonitrile). Original Russian Text ? V.A. Keskinov, A.K. Pyartman, N.A. Charykov, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 4, pp. 701–704.     

Investigation of phase equilibria in the Er2O3–Na2O–P2O5 system: the partial system ErPO4–NaPO3–Er(PO3)3

The partial system ErPO₄–NaPO₃–Er(PO₃)₃ of the Er₂O₃–Na₂O–P₂O₅ oxide system has been investigated by thermoanalytical methods and X-ray powder diffraction. On the basis of the obtained results the phase diagram of the partial system is proposed. The system is bounded by three subsystems: (i) ErPO₄–Er(PO₃)₃, (ii) Er(PO₃)₃–NaPO₃ and (iii) ErPO₄–NaPO₃. Their phase diagrams are proposed. In the Er(PO₃)₃–NaPO₃ subsystem an intermediate compound NaEr(PO₃)₄ occurs; it melts incongruently at 655 °C. It was found that ErPO₄ and NaEr(PO₃)₄ form a section which is a real system only in the subsolidus region (below 646 °C). Two ternary invariant points (one ternary peritectic and one ternary eutectic) occur in the investigated partial system ErPO₄–NaPO₃–Er(PO₃)₃.     

A spectrophotometric study of the formation of the peroxotitanium(IV) complex and its application to the determination of beryllium

The formation of peroxotitanium(IV) complexes has been studied spectrophotometrically in (a)Ti(IV)-H₂O₂,(b)Ti(IV)-H₂O₂-HF and (c)Ti(IV)-H₂O₂-HF-Be(II) systems containing 2M hydrochloric acid. In system (a),only a 1:1 peroxotitanium(IV) complex is evident. In system (b), the competitive formation of the peroxotitanium(IV) complex and fluorotitanium(IV) complexes is discussed. In system (c), the formation of fluoroberyllium(II) complexes causes an increase in concentration of the peroxotitanium(IV) complex which is proportional to the concentration of added beryllium(II). The determination of beryllium in a Cu-Be alloy was successful with a Ti(IV)-H₂O₂-HF reagent.     

The promoting effect of chelating ligands in the oxidative carbonylation of phenol to diphenyl carbonate catalyzed by Pd–Co–benzoquinone system

The system Pd(OAc)₂/BQ/Co(acac)₃ (BQ=benzoquinone), in combination with tetrabutylammonium bromide (TBAB) as a surfactant agent and a chelating ligand such as 2,9-dimethyl-1,10-phenanthroline (dmphen) or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (dmdpphen), is an efficient catalyst for the oxidative carbonylation of phenol to diphenyl carbonate (DPC). The best results have been obtained using the system Pd(OAc)₂/BQ/Co(acac)₃/dmphen=1/30/8/5 (molar ratio) in which [Pd]=10⁻³ mol l⁻¹ and TBAB/Pd=60/1. This system gives the maximum productivity of 700 mol DPC/mol Pd h at 135°C and under P_tot=60 atm (CO/O₂=10/1 molar ratio). The role of each component of the catalytic system is discussed and a catalytic cycle is proposed.     

Molecular structure of polyethylene obtained in the presence of organic magnesium compounds

The molecular structure of polyethylene obtained by the system TiCl₄-Et₂AlCl-Ph₂Mg was investigated. The polymer has a linear structure with a minimum amount of branching. The unsaturation is caused by the presence of one terminal vinyl group: this is due to the character of termination reactions. The polymer has a narrow molecular weight distribution; the content of low molecular weight products is lower than in polyethylene obtained with the TiCl₄ Et₂AlCl system and a high molecular weight tail is absent. The system containing a small amount of Ph₂Mg (a “modified” system) is more similar in activity, just as in the structure of the resulting polymer, to the TiCl₄-Et₂AlCl system. These phenomena might be related to different valent states of titanium at different Ph₂Mg/TiCl₄ molar ratios and to possible absence or presence of active centres of different valence.     

Initiation and termination mechanism in the cooligomerization of the styrene–methyl methacrylate–carbon tetrachloride system

The analysis of the endgroups of the oligomers produced in the styrene (A)–CCl₄(S) system (system I), the methyl methacrylate(B)–CCl₄ system (system II), and the styrene–methyl methacrylate–CCl₄ system (system III) was carried out in order to clarify the mechanism of the initiation, transfer, and termination. In system I, the number of Cl atoms per oligomer molecule N_Cl increases with the molar ratio of [S]/[A] when the molar ratio of [S]/[A] is below unity and is about four when the molar ratio of [S]/[A] is above unity, and the number of initiator fragments per oligomer molecule N_I decreases with the increase in the molar ratio of [S]/[A]. In system II, N_Cl is about 0.45 over a considerably wide range of the molar ratio of [S]/[B]. In system III, N_Cl increases and N_I decreases with the increase in the molar ratios of [S]/([A] + [B]) and [A]/[B]. From the data of N_Cl and N_I, the fraction I_CC14 of the initiation by the tri-chloromethyl radical in the overall initiation reactions and the fraction T_CC14 of the chain transfer reaction of the growing radical of styrene in all the reactions which produce the cooligomer in the system III were calculated. I_CCl3 and T_CC14 both increase with the molar ratios [S]/([A] + [B]) and [A]/[B].     

Phase behavior of binary system of bromobenzene–chlorobenzene confined in SBA-15 and MCM-41

Phase behavior of binary system of bromobenzene-chlorobenzene（C6H₅Br-C₆H₅Cl） confined in SBA-15 and MCM-41（pore diameter 8 nm,3.8 nm,respectively） has been investigated by means of differential scanning calorimetry（DSC）.Phase diagram of C₆H₅Br-C₆H₅Cl system confined in SBA-15 is a type of the complete miscible both in liquid and solid state,the same phase behavior as the bulk system.However,the phase diagram comprises only one boundary line,which is shifted down 22-36 K with respect to the bulk system.C₆H₅Br,C₆H₅Cl or the mixture within nanopores of MCM-41 is nonfreezing.The different phase behavior of the system confined in SBA-15 and MCM-41 is thought mainly due to the relative size of pore to molecule.     

SYNTHESIS OF cis-1, 4-POLYBUTADIENE WITH NICKEL CATALYST INVESTIGATIONS ON INTERACTIONS BETWEEN THE CATALYTIC COMPONENTS BY USING UV-VIS SPECTRUM

Ni(Ⅱ) naphthenate in hydrogenated gasoline or toluene will appear light green, which is the result of absorption in the red and blue bands of the spectrum. The three peaks caused by the spin-allowed d-d transitions are 403, 680, and 1170nm respectively, and are similar to those of Ni(H_2O)_6~(+2). The configuration of Ni(Ⅱ) complex is octabedral.In a two-component system of Ni(naph)_2-Al(i-Bu)_3, the naphthenate ligand attached to Ni(Ⅱ) can be exchanged for the alkyl group on tri-isobutylaluminium, if Al(i-Bu)_3/Ni(naph)_2 in a system. containing metalalkyl and naphthenate does not exceed the value of 0.53. At a higher ratio, Al(i-Bu)_3/Ni(naph)_2>0.53, Ni(Ⅱ) is reduced to Ni(Ⅰ) and Ni(O).In a two-component system Ni(naph)_2-BF_3·OEt_2, a part of the naphthenate can be exchanged for halogen. A new Ni(Ⅱ) complex is formed, which consists of three new d-d bands in the region 360-1660 nm.     

聚合物载体-稀土金属络合物的表征及其催化聚合共轭双烯的活性

本文采用含一定量功能团的直链碳氢共聚物作为载体,如苯乙烯-丙烯酸共聚物(SAAC),苯乙烯-2-(甲基亚硫酰基)乙基甲基丙烯酸酯共聚物(SMC)。介绍了这类聚合物载体-稀土金属络合物的合成方法,讨论了它们的红外光谱。聚合物载体-钕络合物催化剂具有很高的催化活性和定向效应.SAAC·Nd 三元体系的催化效率高达170kg聚丁二烯/gNd·小时,SMC·NdCl_3 二元体系的催化效率是小分子氯化钕二甲基亚砜络合物 NdCl_3·4DMSO的 2—3倍。聚丁二烯顺式-1,4结构含量在 98％以上。体系也适用于异戊二烯的聚合,产物顺式-1,4含量在95％左右。     

Effect of the mixture t - BuCl/SnCl4 on the cationic polymerization of isobutylene

The polymerizations of isobutylene initiated with the system tert-butyl chloride (t-BuCl)/SnCl₄ and carried out in CH₂Cl₂ at −20°C and −78°C were investigated. The results obtained demonstrate that the presence of t-BuCl in the polymerizing system gives rise to a PIB product with a distinctly bimodal MWD. The higher-molecular weight (HMW) PIB, M̄_n = 20000, I=M̄_w/M̄_n ∼ 2.5, is the result of existence of the protogenic initiation with residual water in the reaction system. The lower-molecular weight (LMW) PIB, M̄_n < 600, M̄_w/M̄_n ≤ 1.4, is the product of polymerization initiated presumably with a complex t-BuCl-SnCl₄-H₂O. To elucidate the reaction mechanism of the polymerization initiated with the complex, a series of similar isobutylene polymerizations using the initiation system 2,5-dichloro-2,5-dimethylhexane (DDH)/SnCl₄ was run and the oily LMW PIB samples were investigated by ¹H-NMR. A new polymerization mechanism describing the role of DDH and t-BuCl is suggested.