漂白活化剂TAED的制备

本文较系统地介绍了ＴＡＥＤ的实验室合成方法     

漂白活化剂四乙酰乙二胺的制备

以乙二胺、乙酸和乙酸酐为原料，采用两步同釜连续制备工艺，制备漂白活化剂四乙酰乙二胺（ＴＡＥＤ），产率达７５％。     

漂白活化剂四乙酰乙二胺的制备

本文论述了以乙二胺、乙酸和乙酸酐为原料，采用两步同釜连续制备工艺，分别在１２０℃和１４０℃温度下，制备漂白活化剂四乙酰乙二胺（ＴＡＥＤ）的方法     

漂白活化剂TAED合成工艺的研究

四乙酰乙二胺，即ＴＡＥＤ是一种低温型漂白活化剂，采用二步合成法，在合理工艺条件下合成，产品质量达到国外同类产品水平。     

一种新型无磷洗涤助剂层状结晶二硅酸钠的研制

研究用芒硝生产泡花碱制备新型无磷洗涤助剂层状结晶二硅酸钠的方法,探讨了原料中各种杂质对产品质量的影响及工艺的控制。结果表明,在最佳工艺条件下,所得产品的钙离子交换力大于300mgCaCO3/g,镁离子结合力大于400mgMgCO3/g。     

四乙酰乙二胺在纸浆漂助漂白中作用的研究

本文主要论述了四乙酰乙二胺对纸浆的无氯漂白和在有氯漂白过程中的助漂作用,实现常温下过硼酸钠的无氯漂白,以及有氯漂白的减氯和提高白度。     

急需发展的新型环保洗涤助剂—层状结晶二硅酸钠

目前作为传统的洗涤助剂三聚磷酸钠的主要替代品是4A沸石,但4A沸石作为磷酸盐的替代品,却不是十全十美的。4A沸石虽广泛大量地用于合成洗涤剂,但其功能却不能完全替代磷酸盐,因为4A沸石不具备碱性及表面     

新型无磷洗涤剂助剂层状二硅酸钠特性的比较

通过对所合成的无磷洗涤剂助剂层状二硅酸钠(δ相、β相、α相),用XRD、SEM、^29SiNMR、钙脱除容量和速率、pH值等方法进行了物理化学特性的比较研究。得到了所合成的样品δ相和α相是纯相;β相样品是以．β相为主含δ相的复合相。钙离子脱除特性测定结果表明：3的钙离子脱除容量分别为336mg／g(以CaCO3计,下同,δ相)、241mg／g(β相)和181mg／g(α相),有较大差异;而且3的钙离子脱除速率有明显差别,其中以δ相的脱除速率最快。结果还表明：良好的钙离子脱除容量,较快的钙离子脱除速率是δ相层状二硅酸钠具有比较好的洗涤效果的重要原因。     

新型洗涤助剂--层状结晶硅酸钠的开发与应用

简要介绍了一种新型洗涤助剂——层状结晶硅酸钠产品的理化性质、质量指标、生产工艺、生产中的“三废”处理及其在洗涤剂等领域的应用等情况。其生产工艺符合清洁生产的要求,具有较好的经济效益及环境效益。该产品的生产需消耗大量烧碱。对我国氯碱行业平衡烧碱非常有益。     

新型无磷洗涤剂助剂——层状结晶硅酸盐

概述了无磷洗涤剂助剂硅酸盐、无定型硅酸盐、晶状硅酸盐,尤其是层状硅酸盐的各种性能,并对4A沸石及其他助剂的市场状况作了阐述,指出4A沸石仍是洗涤剂行业的主要代磷助剂,层状硅酸盐的价格／性能比将是众多厂家的主要关注点。     

新型无磷洗涤剂助剂层状二硅酸钠的合成与性质研究

对新型无磷洗涤剂助剂层状二硅酸钠的合成规律、基本性质（钙交换容量、pH值）、稳定性进行了研究。实验证明,δ相层状二硅酸钠的适宜 合成条件是、工业水玻璃数为2（Si/Na=1),恒温温度700℃、恒温时间30min－60min。实验合成了能够在100℃蒸馏水中保持晶体结构稳定300min的δ相层状二硅酸钠（SKS－6）样品。     

Polyamide 6 Filled with Melamine Cyanurate and Layered Silicates: Evaluation of Flame Retardancy and Physical Properties

The efficiency of melamine cyanurate and a clay filler for improving the flame retardancy and other physical properties of polyamide 6 was examined. Partially intercalated‐exfoliated morphologies were obtained. Nanocomposites suffered from polymer degradation during compounding, while the molecular weight was enhanced in the case of the flame retarded samples. Silicates were shown to restrain crystallization, whereas melamine cyanurate induced heterogeneous nucleation. Both additives positively influenced the tensile modulus of the prepared samples, decreasing their ability to elongate. With respect to the UL94 flammability test, melamine cyanurate was proved to be not sufficiently capable of increasing the tendency of nanocomposites to drip, negatively affecting flammability.

     

Efficient Immobilization of Yeast Transketolase on Layered Double Hydroxides and Application for Ketose Synthesis

Transketolase (TK) from S. cerevisiae was successfully immobilized on layered double hydroxides (LDH) using simple, affordable and efficient adsorption and coprecipitation based immobilization procedures. Optimization of the preparation was performed using zinc aluminium nitrate (Zn₂Al‐NO₃) and magnesium aluminium nitrate (Mg₂Al‐NO₃) LDH as immobilization supports, and the protein‐to‐LDH weight ratio (Q) was varied. The highest immobilization yields (98–99%) and highest relative specific activities (4.2–4.4 U⋅mg⁻¹ for the immobilized enzyme compared to 4.5 U⋅mg⁻¹ for the free enzyme) were both achieved when using a protein‐to‐LDH weight ratio (Q) of 0.38. Efficient lyophilization of the LDH‐TK bionanocomposites thus synthesized was proven to allow easy use and storage of the supported TK with no significant loss of activity over a three‐month period. The kinetic parameters of the LDH‐TK enzyme were comparable to those of the free TK. The LDH‐TK enzyme was finally tested for the synthesis of L ‐erythrulose starting from hydroxypyruvate lithium salt (Li‐HPA) and glycolaldehyde (GA) as substrates. L ‐erythrulose was characterized and obtained with an isolated yield of 56% similar to that obtained with free TK. The reusability of the LDH‐TK biohybrid material was then investigated, and we found no loss of enzymatic activity over six cycles.     

Highly Efficient Overall Water Splitting Through Optimization of Preparation and Operation Conditions of Layered Perovskite Photocatalysts

The layered perovskite materials were found to give the high photocatalytic activity in water splitting reaction under UV irradiation, where the electronic structure of perovskite slab constructing the layered structure (the total cation valency) was the most crucial factor to the high photocatalytic activity. Both the excessive cation valency and the layered structure were required for active photocatalysts, while the slab thickness of layered perovskites had an insignificant effect on water-splitting activity. In order to identify key variables that affected photocatalytic activity and to optimize the performance of (110) layered perovskite, La₂Ti₂O₇ was modified by various methods. The optimum amount of loaded nickel had a great effect and the amount depended on the surface area of the perovskite phase. When an alkaline-earth element such as Ba, Sr, and Ca was doped on La₂Ti₂O₇, the photocatalytic activity was enhanced markedly. Introduction of an alkaline hydroxide into the reaction system as an external additive enhanced the activity further showing extremely high quantum yields close to 50%.     

Polyamide 6 Composites with Melamine Polyphosphate and Layered Silicates: Evaluation of Flame Retardancy and Physical Properties

The potential synergy of melamine polyphosphate and layered silicates for enhancing the flame retardancy and physical properties of polyamide 6 is investigated. Through melt blending, exfoliated nanocomposites were prepared, suffering, however, from polymer degradation. In the presence of the additives, the ability of polyamide 6 to crystallize was restrained and its thermal stability was deteriorated. Nevertheless, the stiffness of the polymer was increased, yet at the expense of ductility. Apart form stiffness, the additives exerted a positive effect on the fire resistance of polyamide 6; melamine polyphosphate and layered silicates cooperated during combustion to provoke the formation of a superficial protective barrier, yielding materials of inferior flammability.

     

Research Advancement in High-Performance Polyamides and Polyamide Blends Loaded with Layered Silicate

Polyamide comprises one of the major classes of polymers. Layered silicates (nanofiller) may enhance properties of polyamide-based hybrids even at very low content. Aliphatic polyamides (nylons) have often been chosen for commercial applications because of excellent physical and chemical properties. Aromatic polyamides (aramids) and aliphatic-aromatic polyamides have been predominantly useful as high-performance materials due to stiffness, low density, and low cost. Recently polyamide blends have become an important route to high-performance materials. Binary blends of polyamide/polypropylene, polyamide/polystyrene, polyamide/polymethyl methacrylate, polyamide/polyurethane, and others have been reported for nanocomposite formation with organoclay. However, ternary blend nanocomposite with nanoclays (PA6/mSEBS, PA6/EPDM-g-MA/H-HDPE) is rarely explored.     

Synthesis and Characterisation of Anhydride‐Cured Epoxy Nanocomposites Containing Layered Silicates Modified with Phenolic Alkylimidazolineamide Cations

Summary: Phenolic alkylimidazolineamides were prepared and applied as modifiers in order to render layered silicates organophilic and to prepare polymeric nanocomposites. The imidazolineamine, 2‐{2‐[heptadec‐8‐enyl]‐4,5‐dihydro‐1‐imidazol‐1‐yl}‐1‐ethaneamine (IA), was reacted in bulk with one of the two phenolic compounds, ethyl 4‐hydroxybenzoate (P) or methyl 3‐[3,5‐di(tert‐butyl)‐4‐hydroxyphenyl]propionate (HP), which is an intermediate for antioxidants, to prepare the two phenolic imidazolineamides, PIA and HPIA. During protonation in water, both phenolic imadazolineamides were used successfully to exchange interlayer sodium cations of sodium bentonite and fluorohectorite, thus producing organophilic layered silicates with an increased interlayer distance of around 3.3 nm. The new phenolic organophilic layered silicates represent a novel class of phenolic organic/inorganic hybrid materials. They were applied as fillers in hexahydrophthalic anhydride‐cured bisphenol‐A diglycidyl ether (BADGE). Thermal analysis (DSC), transmission electron microscopy (TEM), wide angle X‐ray scattering (WAXS), and mechanical tests were used to evaluate the thermal, mechanical, and morphological properties. Although fracture toughness, measured as the stress intensity factor, K_Ic, and the energy release rate, G_Ic, increased by around 50% with increasing silicate content without sacrificing glass temperature, both tensile strength and Young's modulus increased only marginally. Low matrix reinforcement was attributed to inadequate compatibility matching, as evidenced by the slightly lower interlayer distances of the layered silicates encapsulated in the epoxy matrix.

Representative TEM micrographs of the sample ER‐bent‐PIA/10.     

Layered Double Hydroxides Derived from MIL-88A(Fe) as an Efficient Adsorbent for Enhanced Removal of Lead (II) from Water

The efficient removal of lead (II) from aqueous solution remains a big problem and the development of novel nanomaterials as adsorbents by various technologies to solve this problem is promising. This study contributed a novel nanostructure of MIL-88A-layered double hydroxides (LDHs) as the adsorbent for Pb²⁺, which was synthesized by a two-step solvothermal method with MIL-88A(Fe) as the precursor. The as-prepared material featured a chestnut-like core-shell structure, and exhibited excellent removal performance towards Pb²⁺ from water in comparison to MIL-88A(Fe) and LDHs (directly synthesized). The adsorption of Pb²⁺ by the MIL-88A-LDHs conformed to the pseudo-second-order kinetic model and the Langmuir and Freundlich isotherm models. The maximal adsorption capacity was 526.32, 625.00, and 909.09 mg g⁻¹ at 278, 298, and 318 K, respectively. The thermodynamic parameters suggested that the adsorption was an endothermic, entropy-increasing, and spontaneous reaction. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface complexation was mostly responsible for Pb²⁺ elimination. The MIL-88A-LDHs can be readily regenerated and showed good cyclic performance towards Pb²⁺. Thus, the as-prepared MIL-88A-LDHs may hold promise for the elimination of aqueous heavy metals.     

Chabazite Synthesis and Its Exchange with Ti,Zn, Cu,Ag and Au for Efficient Photocatalytic Degradation of Methylene Blue Dye

A chabazite-type zeolite was prepared by the hydrothermal method. Before ion exchange, the chabazite was activated with ammonium chloride (NH₄Cl). The ion exchange process was carried out at a controlled temperature and constant stirring to obtain ion-exchanged chabazites of Ti⁴⁺ chabazite (TiCHA), Zn²⁺ chabazite (ZnCHA), Cu²⁺ chabazite (CuCHA), Ag⁺ chabazite (AgCHA) and Au³⁺ chabazite (AuCHA). Modified chabazite samples were characterized by X-ray diffraction (XRD), scanning electron microscope equipped with energy-dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), N₂ adsorption methods and UV–visible diffuse reflectance spectroscopy (DRS). XRD results revealed that the chabazite structure did not undergo any modification during the exchange treatments. The photocatalytic activity of chabazite samples was evaluated by the degradation of methylene blue (MB) in the presence of H₂O₂ under ultraviolet (UV) light illumination. The photodegradation results showed a higher degradation efficiency of modified chabazites, compared to the synthesized chabazite. CuCHA showed an efficiency of 98.92% in MB degradation, with a constant of k = 0.0266 min⁻¹ following a first-order kinetic mechanism. Then, it was demonstrated that the modified chabazites could be used for the photodegradation of dyes.