Recent progress in the manufacture of alkanesulfonates: Photosulfochlorination of single-chain length (C12−C16) n-alkanes using SO2Cl2 at high conversion rates in pure phase and in the presence of solvent

Increasing concentration of sulfuryl chloride during the photosulfochlorination reaction under visible light shows that under these conditions n-alkanes react at high conversion rates instead of the conversion rate of 15% reported in the literature. This photosulfochlorination with sulfuryl chloride leads to better and more interesting results compared with those of photosulfochlorination by gas mixture. Indeed, nearly total conversion of n-alkanes, specifically n-heptane, n-dodecane, n-tetradecane, and n-hexadecane, occurred in pure phase, with a quantitative global yield, a sulfochlorination-to-chlorination molar ratio of about 1, and a relative reactivity of secondary to primary hydrogen of about 2.5, at a reaction temperature of 30°C and a reaction time of 120 min, using 2×10⁻² mol L⁻¹ of pyridine. Under these conditions, no polysulfochlorinated compounds are detected. These results are further improved using chlorobenzene as the solvent, instead of benzene. Indeed, the sulfochlorination of n-heptane at a conversion rate of 80% in the presence of chlorobenzene leads also to a quantitative reaction yield, a higher RSO₂Cl/RCl molar ratio, and, as expected, a high selectivity of secondary over primary hydrogen. Under these conditions, sulfochlorination of long-chain n-alkanes leads to the highest RSO₂Cl/RCl molar ratio for n-dodecane, n-tetradecane, and n-hexadecane belonging to detergent range, and the value of the molar ratio for these is between 1.45 and 1.7. The isomeric distribution of sulfochlorinated compounds obtained during sulfochlorination in the presence of solvent resembles that of secondary alkanesul-fonates produced by sulfoxidation reaction, whereas that obtained in pure phase has a similar conversion rate, is rich in primary isomer, and thus is different from that of classic radical reactions such as photochlorination or photosulfochlorination with gas mixture.     

Electrical and magnetic properties of NdCuPb compound

Electrical and magnetic properties of NdCuPb compound were investigated by means of electrical resistivity, magnetization measurements in the temperature range 1.5–100 K. Low-field dc susceptibility goes through a maximum at T_N=13.2  K, indicating a paramagnetic to an antiferromagnetic transition and then follows a sharp peak at T=5.9  K. The susceptibility data exhibits a Curie–Weiss like behavior in the paramagnetic regime and the effective moment per neodium atom is found to be 3.62μ_B from the data at temperatures above 42 K. This value is exactly equal to that for Nd³⁺, while at lower temperatures, the data yields a little bit less than its free ion value. The ratio M/H versus temperature T curves for different values of the magnetic field split into multiple branches at about T=42  K due to crystalline field effects.In addition, electrical resistivity in a magnetic field up to 120 kOe was also measured in the same temperature range. The resistivity gives non-metallic behavior. The antiferromagnetic transition is clearly discern by a “Cr-like” anomaly at about 13 K, followed by a sharp increase in the resistivity (like a jump) at T=5.9  K where the susceptibility gives similar effect. On other hand, the magnetic contribution to the resistivity begins to decrease at T=42  K at which M/H curves merges. All these behavior may be attributed to crystal-field-splitting of neodium atoms’levels.     

Corrosion behavior of a superduplex stainless steel in chloride aqueous solution

Super duplex stainless steels (SDSS) have been widely used as structural materials for chemical plants (especially in those engaged in phosphoric acid production), in the hydrometallurgy industries, and as materials for offshore applications due to their excellent corrosion resistance in chloride environments, compared with other commercial types of ferritic stainless steels. These alloys also possess superior weldability and better mechanical properties than austenitic stainless steels. However, due to their two-phase structure, the nature of which is very dependent on their composition and thermal history, the behavior of SDSS regarding localized corrosion appears difficult to predict, especially in chloride environments. To improve their final properties, the effect of the partition of the alloying elements between the two phases, and the composition and microstructure of each phase are the key to understanding the localized corrosion phenomena of SDSS. This paper concerns the effects of the SDSS microstructure and heat treatment on the SDSS corrosion resistance in aqueous solutions, containing different amounts of NaCl at room temperature.     

Rare-earth diiodides and derivatives

The rare-earth diiodides, MI₂, may be synthesized from the corresponding triiodides, MI₃, by reduction with their metals at elevated temperatures or, alternatively, through so-called metallothermic reduction reactions with alkaline or alkaline-earth metals. In these cases, ternary iodides may be obtained that may be derived from the binary diiodides by either formal addition or substitution. Prominent formula types that are thus obtained are A^IMI₃, or the mixed-valent A^I₅M^II₂M^IIII₁₂ and A^IIMI₄ with A^I and A^II representing alkaline or alkaline-earth elements (and their analogues), respectively. Further iodides that are relevant in these systems are, for example, Pr₂I₅, Ba₆Pr₃I₁₉ and interstitially stabilized phases such as {Er₁₄(N₂)(C₂)₂}I₂₄, La₉O₄I₁₆ and Ba{Ce₄N₂}I₈.     

稀土加工助剂兼热稳定剂RHS—1

本文介绍一种新型无毒透明ＰＶＣ添加剂ＲＨＳ－１。ＲＨＳ－１的主要化学成分是一种难溶稀土有机酸盐，兼具加工助剂和热稳定剂的作用，作为加工助剂，其效能达到ＡＣＲ－２０１的二倍以上，ＲＨＳ－１的热稳定效能不及１７ＭＯＫ，但由于两者具体有协同作用，ＲＨＳ－１可用于代替部分１７ＭＯＫ。     

添加RE的银基汞齐合金的研究和应用

用雾化技术制备Ａｇ－Ｃｕ－Ｓｎ汞齐合金并添加ＲＥ及Ｉｎ，Ｌｉ，研究其性能和结构，临床试验表明，此合金具有优良综合性能，Ｈｇ用量少，成本也低。     

氮化硅的α→β相变的影响因素

本文研究了氮化硅α→β相变的诸影响因素。发现 Y_2O_3添加剂具有最显著的相变促进作用,而 La_2O_3添加剂促进相变的作用最小,但后者对促进 Si_(?)N_4致密化的作用较前者显著。原始氮化硅粉末的比表面、杂质含量及颗粒形貌均会影响α→β相变的程度。     

Aromatic polyesters (polyarylates) containing arylene sulfone ether linkages

A series of soluble aromatic polyesters (polyarylates) containing arylene sulfone ether linkages and having inherent viscosities of 0.36–1.10 dl/g were prepared by the two-phase low temperature polycondensation of 4,4′-[sulfonyl-bis(p-phenyleneoxy)]dibenzoyl chloride and 3,3′-[sulfonylbis(p-phenyleneoxy)]-dibenzoyl chloride with various bisphenols in an organic solvent-aqueous alkaline solution system in the presence of a phase transfer catalyst. Bisphenols 4,4′-[sulfonylbis(p-phenyleneoxy)]diphenol and 3,3′-[sulfonylbis(p-phenyleneoxy)]-diphenol were synthesized in quantitative yields by an improved procedure. The aromatic polyesters prepared were characterized by infrared spectroscopy, elemental analysis, solution viscosity, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction. The polyesters prepared had glass transition temperatures in the range 150–230°C and initial decomposition temperatures of 397–491°C. They gave transparent, tough and flexible films by the solution casting technique.     

All solid-state electrochromic window of electrodeposited WO3 and prussian blue film with PVC gel electrolyte

An all-solid-state electrochromic window (SEW) of prussian blue and electrodeposited WO₃ film with poly(vinyl chloride) PVC gel electrolyte with high conductivity (2 mS/cm) at room temperature has been fabricated. The SEW has been found to be excellent for electrochromism and memory characteristics. W 4f core level of WO₃ film as a function of the injected charge has been investigated using X-ray photoelectron spectroscopy (XPS). W 4f peaks become broader after coloration.     

Electrochemical behaviour of erbium in the eutectic LiCl-KCl at W and Al electrodes

The electrochemical behaviour of Er(III) was studied in the molten LiCl-KCl eutectic for temperatures ranging from 653 to 823 K. Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry and chronoamperometry were used in order to study the reaction mechanism and the transport parameters of electroactive species at a tungsten electrode. The results showed that in the eutectic LiCl-KCl, the reduction of Er(III) occurs in a step with a global exchange of three electrons, and that electrocrystallization plays an important role in the electrodeposition process. Chronoamperometric studies indicated instantaneous nucleation of erbium with three-dimensional growth of the nuclei whatever the applied overpotential.Mass transport towards the electrode is a simple diffusion process, and the temperature dependence of the diffusion coefficient of the electroactive specie Er(III) was written in the following equation: