提溴废液脱色净化研究

提溴废液是海水日晒制盐→提钾→提溴后的母液,其氯化镁质量浓度高达400～450 g/L,但其浊度和色度均较大,影响其加工的精细化工产品色泽和质量。研究了对提溴废液进行物理法脱色和化学法脱色,结果表明,提溴废液的色度是由有机有色物质造成的;砂滤能很好地去除悬浮物,使浊度从40.9 NTU降到约2 NTU,但脱色率仅为41%;活性炭吸附的脱色率为60%,砂滤和活性炭吸附的脱色效果均不理想。最佳实验条件下次氯酸钠和双氧水的脱色率分别为80%和79%,能达到较好的脱色效果,综合氧化时间、氧化温度考虑,次氯酸钠脱色优于双氧水脱色;为此提溴废液脱色净化工艺选择砂滤预处理+次氯酸钠脱色,脱色的最佳条件：次氯酸钠加入量8%（质量分数）、pH=6.0、氧化时间为40 min、脱色率为80%。     

室温无溶剂条件下离子液体催化的Knoevenagel缩合反应

在室温无外加溶剂条件下,甲酸乙醇铵离子液体催化一系列芳醛和活泼亚甲基化合物进行Knoevenagel缩合反应,短时间内以高产率生产相应产物。实验表明甲酸乙醇铵可以有效地催化Knoevenagel缩合反应,并可以循环使用。     

Proton conducting membrane containing room temperature ionic liquid

A new proton conducting membrane containing room temperature ionic liquid: 2,3-dimethyl-1-octylimidazolium trifluoromethanesulfonylimide (DMOImTFSI) and polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) has been developed in the present work. The addition of bis(trifluoromethanesulphonyl)imide (HN(CF₃SO₂)₂) to this membrane results in an increase in conductivity by one order of magnitude at 25 °C. The membrane shows a conductivity of 2.74 × 10⁻³ S/cm at 130 °C along with good mechanical stability. The membrane was tested in a commercial fuel cell test station at 100 °C with dry hydrogen and oxygen gas reactants using Pt/C electrodes. The membrane containing the ionic liquid has been found to be electroactive for hydrogen oxidation and oxygen reduction at the platinum electrode and can be developed for use in proton exchange membrane fuel cell (PEMFC) under non-humid conditions at elevated temperatures.     

室温离子液体酸催化剂研究进展

综述了室温离子液体酸的组成、结构性质及其在催化酯化反应、Friedel-Crafts反应、烷基化反应、催化裂解、亲电反应及缩合反应等方面的应用进展.同传统酸催化剂体系相比,使用室温离子液体酸催化剂的反应体系的选择性、活性及催化剂循环次数均可得到改善,并能有效地抑制副反应,缩短反应时间并简化产物与体系的分离过程.探索室温离子液体酸对于特定反应的催化性能,是现今国内外相关研究领域的一个热点.     

Covalent cross-linking of polymers at room temperature

Thermoplastic materials used in coatings, paints and adhesives as well as structural applications for sensitive substrates, such as wood, paper or polymers, often lack the required chemical and environmental resistance for many applications, which can be overcome by covalent cross-linking. Covalent cross-linking improves chemical and mechanical properties of the material and has been used for many different materials and applications. Room temperature cross-linking can be initiated by different mechanisms and eliminates energy intensive heating as well as conditions potentially harmful for the substrate. The present article focuses on cross-linking strategies applied for different materials, such as thermoplastics and thermosets. It is organized by material class, followed by an overview about triggering mechanisms for cross-linking reactions at room temperature. The authors hope to provide helpful insights about the methods for covalent cross-linking already published.     

室温固化高性能胶粘剂的研制

为了改善环氧树脂(EP)胶粘剂对某些金属和非金属材料的粘接性能,采用自制的增韧剂改性EP,制备了一种可室温固化的无溶剂双组分EP胶粘剂。考察了增韧剂用量、不同的室温固化剂及表面处理方法对金属和非金属材料的粘接性能、耐热性能和耐介质性能的影响。实验结果表明,该胶粘剂对金属和非金属都具有良好的粘接性能;用于PVC和ABS粘接时,则被粘材料被破坏;用于聚四氟乙烯(PTFE)和聚乙烯(PE)粘接时,其最高剪切强度分别为1.9 MPa和1.8 MPa。     

Novel geopolymeric material cured at room temperature

Abstract

Abstract

Alkali activated binders are a new class of binding material with comparable or enhanced performance to Portland cement. These binding materials are obtained by a chemical reaction between an aluminosilicate material and a highly alkaline solution. In most cases, the setting hardening process of this binder is performed at high curing temperatures. In this paper, alkali activated mortars based on vitreous calcium aluminosilicate (VCAS) cured at room temperature are evaluated. Mechanical strength development and microstructural analysis (scanning electron microscopy, thermogravimetric analysis, X-ray diffraction and mercury intrusion porosimetry) of these materials are performed. Mortars yielded compressive strength ～89 MPa after 360 days. This is the first time that VCAS is used as aluminosilicate source material in the production of alkali activated mortars cured at room temperature.     

环保型常温锌钙系磷化工艺

研究了(NH4)2MoO4、Ca(NO3)2、硫脲、柠檬酸、温度,时间和pH等工艺条件对磷化膜层的耐蚀性和表面状况的影响.通过正交试验法确定的最佳工艺配方为:氧化锌4.5 g/L,磷酸11.25 mL/L,硝酸钙8 g/L,钼酸铵4.0 g/L,硫脲1.5 g/L,柠檬酸1.4 g/L,温度25～35℃,时间20 min以上,pH 2.5～3.0.该磷化工艺操作简单,清洁环保,常温即可磷化,使用周期较长,易维护.     

室温固化端羧基液体氟橡胶的性能研究

以高Mr(相对分子质量)氟橡胶(牌号F2461)为主要原料、BTEAC(苄基三乙基氯化铵)为相转移催化剂、丙酮为溶剂、H_2O_2(双氧水)为氧化剂和KOH(氢氧化钾)为碱,采用氧化降解法制得低Mr端羧基液体氟橡胶;然后以此为基体、PCDI(聚碳化二亚胺)为固化剂和THF(四氢呋喃)为溶剂,采用共混法制得可室温固化的端羧基液体氟橡胶。研究结果表明:当m(PCDI)∶m(液体氟橡胶中的—COOH)=1.200∶0.012时,端羧基液体氟橡胶固化产物的力学性能相对最好,并且具有优异的耐热性和耐介质性。侧链含醚键的端羧基液体氟橡胶固化产物与普通的端羧基液体氟橡胶固化产物相比,前者具有较好的低温性能(玻璃化转变温度为-33.26~℃),并且力学性能更优,但耐热性稍差。     

The chemistry of alkyl dihalides in zeolite NaX at room temperature

Alkyl dihalides adsorbed in NaX zeolite undergo room temperature, substitutional dehalogenation, single dehydrohalogenation, combined dehalogenation–dehydrohalogenation, or two consecutive dehydrohalogenations. The preference for a particular reaction depends on the nature and relative positions of the halogens, and on alkyl chain length. Nuclear magnetic resonance chemical shifts and mass spectrometric assignments to the reagents and products indicate the particular reactions taking place.All of the alkyl dihalides containing the iodo group (diiodoalkanes) studied (αα, αβ, α,γ) undergo only substitutional dehalogenation to form zeolite bound iodoalkoxy. The same chemistry was observed with both short and long chain diiodoalkanes. The dichloroalkane and dibromoalkane chemistry is dependent on the relative halogen positions and the alkyl chain length. The α, α dichloroalkanes and dibromoalkanes examined by us undergo single dehydrohalogenation, with the exception of 2,2-dichloropropane, which forms a mixture of dehydrohalogenation and substitutional dehalogenation products. The chemistry of α, β alkyl dihalides (Cl, Br) in NaX is dependent on the carbon chain length. The dihaloethanes (Cl, Br) undergo both substitutional dehalogenation and dehydrohalogenation. As the chain length increases to three carbon atoms or more, only dehydrohalogenation reactions take place. No alkyne products were observed with α, β dichloroalkanes and dibromoalkanes, an indication that NaX is too weak a base to initiate sequential dehydrohalogenations. The chemistry of α, γ dichloroalkanes and dibromoalkanes were also dependent on the chain length. The α, γ dihalopropanes (Cl, Br) in NaX form a propene-framework bound product, associated with dehydrohalogenation and subsequent substitutional dehalogenation. The α, γ dihalobutanes (Cl, Br) undergo two consecutive dehydrohalogenations to form dienes.     

The effect of temperature on coalescence of liquid drops at liquid/liquid interfaces

Drop/interface coalescence times measured at 293–343K are reported for three oil/water systems (benzene, paraffin oil and 1,1,2,2-tetrabromoethane) with different interface ages. The anomalous coalescence behavior of water droplets is explained by considering the static electrical double-layer residing at the interface which influences the film thinning and the film rupture processes. Analyses using simplified coalescence models reveal that the incorporation of temperature dependence on the physical properties such as density difference between phases, viscosity of the continuous medium and interfacial tension, does not produce satisfactory agreement with the measured coalescence times. The effect of mutual saturation in contrast to unsaturated systems on coalescence times is illustrated. The reproducibility of the drop/interface coalescence times is examined and explanations are offered, relating the method and the conditions of the experimentation. Finally the importance of both the coalescence time and the film thickness to drop stability analysis is demonstrated.     

Ultrafast synthesis of entropy-stabilized oxide at room temperature

Five-component entropy-stabilized oxide ceramic (Mg_0.2Ni_0.2Co_0.2Cu_0.2Zn_0.2O) has been successfully synthesized by reaction assisted flash sintering at room temperature. Compared to the conventional sintering technique, the starting materials have been completely transformed to a single rocksalt phase in just a few seconds. Analysis suggests that the electric field significantly accelerated the rate of phase transition. These results clearly demonstrate the feasibility of employing the reaction assisted flash sintering technique to fabricate entropy-stabilized oxides with new chemistries and attractive properties.     

The oxidation and scrambling of CO with oxygen at room temperature on Au/ZnO

An FTIR and quadrupole mass study of CO adsorption and oxidation with¹⁶O₂ and¹⁸O₂ on Au/ZnO catalysts is presented. The experimental results indicate that: (i) CO is activated by gold in two molecular forms, a linear carbonyl species bonded at terrace Au sites and a carbonyl species bonded to Au peripheral sites; (ii) a band related to CO adsorbed on Au oxidized sites and a scrambling reaction between CO and¹⁸O₂ indicate that oxygen is also activated on gold sites. The oxygen adsorbed on gold is probably strongly basic, as is the oxygen adsorbed on silver and on copper, and it can easily oxidize CO to CO₂.     

Thermal degradation of polymers. V. Vacuum pyrolysis of poly(p-N,N-dimethylaminostyrene). The products volatile at pyrolysis temperature,liquid or gaseous at room temperature

The products obtained on degradation of poly(p-N,N-dimethylaminostyrene) in vacuo are described. The effects of molecular weight and pyrolysis temperature are discussed and the behavior compared with polystyrene under similar conditions. Product analysis has revealed significant differences between the products of degradation obtained from the two polymers, and mechanisms involving methyl-group migration have been proposed and discussed to account for the anomalous behavior of poly(p-N,N-dimethyl-aminostyrene). The liquid products of pyrolysis have been separated and identified by gas-liquid chromatography using the Kovats retention index, and quantitative analysis is also described. Analysis of the gaseous fraction by mass spectrometry is described.     

室温离子液体[bmim]PF6的合成

用两步法合成了离子液体(bmim)PF_6,莫尔法测定了N-甲基咪唑的转化率,结果发现在第一步季铵化反应过程中,不添加任何有机溶剂,在60℃下反应1h,可获得高达96.0%的转化率。离子交换后的离子液体,经过多次水洗,以及用真空干燥、无水硫酸镁吸附、4A型分子筛干燥可以使溴离子、水含量分别达到10~(-5)数量级、10~(-4)数量级。红外测试确证了[bmim]PF_6的结构。     

稀土复合作用下常温磷化工艺的研究

研究出一种含稀土和淀粉的常温磷化促进剂。探讨了稀土化合物、促进剂、磷化工艺参数如温度、时间和pH值对所得磷化膜外观、膜重和耐蚀性的影响。 结果表明：采用含稀土化合物的磷化促进剂,磷化膜的耐蚀性得到显著提高。     

常温低浓度镀铬工艺研究

提出了一种常温低浓度镀铬工艺。对该工艺所用镀液的深度能力、分散能力、阴极电流效率及其镀层的结合强度和耐腐蚀性能进行了测定。与传统的镀铬工艺相比，该工艺降低了生产成本，提高了生产效率。     

不锈钢常温快速酸洗工艺

为去除不锈钢表面厚氧化皮,常用的酸洗工艺使用温度高、酸洗时间长。采用两步法酸洗工艺,可以在常温下快速去除不锈钢表面厚氧化皮,具有酸洗速度快,使用温度低的优点。酸洗液不含硝酸,环境污染小处理后表面洁净、不失光、不褪色、不泛黄。     

MOx/Y催化剂常温催化臭氧氧化甲苯的性能

以Y分子筛为载体,采用等体积浸渍法制备了MO_x/Y催化剂,并用于常温催化臭氧氧化甲苯反应。采用XRD、BET、H_2-TPR、甲苯吸附对催化剂进行表征,以甲苯转化率维持95%以上的时间(t_(95))为指标对催化性能进行评价。结果表明:10%MnO_2/Y催化剂〔m(MnO_2)/m(Y)=0.1〕具有较大的比表面积(538.6m~2/g)和孔容积(0.440 cm~3/g),较好的催化臭氧氧化甲苯活性(t95=210 min);CuO的加入提高了催化活性,5%MnO_2-5%CuO/Y〔m(MnO_2)/m(Y)=0.05且m(CuO)/m(Y)=0.05〕催化剂上t95=240min,CO_x选择性为80.6%,CO_2与CO摩尔比为4.970。由表征结果可知,较大的比表面积和孔容积有利于甲苯吸附,CuO与Mn O_2之间的相互作用促进了氧化还原性能的提高,进而有利于催化活性的提高。GC-MS结果表明:反应副产物堵塞催化剂孔道,占据催化剂表面活性位,导致催化剂失活。5%MnO_2-5%CuO/Y催化剂失活-再生4次后t_(95)可达220 min。