有机酸催化合成乙酸苄酯

以固体有机酸磺基水杨酸为催化剂、以苄醇、冰乙酸为原料合成乙酸苄酯、苄醇与冰乙酸的摩尔比为1 :1.3 ,反应温度为80℃ ,反应时间为3h ,产品收率达90

固体有机酸催化剂的制备及催化性能

硅胶经酸化预处理,增加表面羟基含量,在碱环境下与环氧氯丙烷反应,表面键合环氧丙烷基团,与NaHSO3或硫酸反应,制备得到钠型有机酸催化剂或氢型有机酸催化剂,采用化学滴定、元素分析、固体H-NMR等手段对实验进行分析表征。结果表明:采用甲基磺酸预处理载体硅胶,30~40℃下与环氧氯丙烷反应6 h,60℃下磺化时间8 h,制得的固体酸酸量达到2.04 mmol/g;固体有机酸催化剂用于生物柴油(脂肪酸甲酯)的合成,循环使用6次,产品收率仍超过80%;固体有机酸催化剂催化酯化活性高,稳定性好。

有机酸催化一锅法制备乙酰化纤维素纳米晶

以对甲苯磺酸为催化剂,滤纸和乙酸为原料,采用一锅法制备了乙酰化纤维素纳米晶(CNC-Ac),并优化了反应条件。结果表明,当对甲基苯磺酸和滤纸的质量比为1∶1时,较佳反应条件为:90%(wt,质量分数)乙酸水溶液和对甲苯磺酸质量比为10∶1,反应温度为90℃,反应时间为90min,该条件下得到的CNC-Ac的产率为79%,分子取代度为0.8。采用SEM、FT-IR、XRD等对CNC-Ac的结构形态进行了表征。研究了CNC-Ac对醋酸纤维素膜的增强性能,结果表明,当CNC-Ac的质量分数为2%时,得到的醋酸纤维素-CNC-Ac纳米复合膜的拉伸强度和断裂伸长率分别为纯醋酸纤维素膜的6.6倍和1.3倍。

有机酸对NiW/Al_2O_3加氢脱硫催化剂性能的影响

在NiW/Al2O3催化剂的制备过程中分别浸渍丁酸、丁二酸、柠檬酸有机助剂,采用程序升温还原(TPR)、X射线衍射(XRD)、高分辨透射电镜(HRTEM)、扫描电子显微镜(SEM)-EDS能谱等对催化剂进行表征,考察不同有机酸对催化剂性质和柴油加氢脱硫活性的影响。结果表明,催化剂制备过程中添加有机酸减弱了金属组分与载体间的相互作用,增加了活性金属的硫化度和WS2晶粒的堆垛层数,减少了金属组分的聚集。除丁酸外,添加丁二酸和柠檬酸催化剂的加氢脱硫活性均高于对比NiW/Al2O3催化剂。

有机酸催化不对称烷基化反应新进展

在有机分子催化的不对称合成领域,手性有机酸催化和有机胺催化是其中两个非常重要的研究方向.羰基化合物的-烷基化反应是形成碳碳键的重要合成策略.手性有机胺催化羰基化合物的不对称-烷基化反应已经有较多的研究报道,

合成表面活性剂烷基多苷的催化剂研究

对以木薯淀粉和十六醇为原料合成表面活性剂—烷基多苷 (APG)的催化剂进行了研究 .试验结果表明 ,无机酸催化剂以硫酸为好 ,有机酸催化剂以对甲苯磺酸为好 。

强酸型阳离子树脂催化合成乙酸正丁酯的研究

本文研究了强酸型阳离子树脂催化酯化合成乙酸正丁酯的方法，合成产率达到95.2％。

TI-PS组份对沥青性能的影响

通过考察不同比例TI-PS组份沥青的软化点、残炭值和粘度 ,发现在PI组份或TS组份不变情况下 ,随着TI-PS组份的改变沥青的三种性能参数值呈直线变化。实验表明 ,有机酸催化可提高沥青TI -PS组份的含量 ,而改变原料沥青的组成与结构也可得到同样效果。

溶胶凝胶法制备Er^(3+)-Yb^(3+)共掺纳米SiO_2粉

利用溶胶-凝胶法合成了Er2O3-Yb2O3-SiO2纳米二氧化硅(SiO2)粉。Er3+和Yb3+直接加入有机酸催化的TEOS反应溶液中,凝胶后经过700~900℃,得到Er3+-Yb3+共掺纳米SiO2粉。样品经过红外光谱、XRD、TEM等分析,结果表明,纳米粉的粒径受有机酸比例和处理温度的影响。在室温PL谱上,样品可观察到较强的1530nm荧光,同时镱的引入对掺铒SiO2纳米粉在1.54μm的荧光发射有增强作用。

Facile fabrication and enhanced photocatalytic performance of visible light responsive UiO-66-NH2/Ag2CO3 composite

A series of UiO-66-NH2/Ag2CO3 Z-scheme heterojunctions were prepared by a simple ion-exchange-solution method using UiO-66-NH2 and semiconductor Ag2CO3 as precursors.The photocatalytic activities of UAC-X(UAC-20,50,100,150,200)Z-scheme heterojunctions toward the hexavalent chromium(Cr(VI))reduction and UAC-100 toward oxidative degradation of four organic dyes like rhodamine B(RhB),methyl orange(MO),congo red(CR),and methylene blue(MB)under visible light irradiation were investigated.The effects of different pH(pH=2,3,4,6,8),small organic acids(citric acid,tartaric acid,and oxalic acid),and foreign ions(ions in tap water and surface water)on Cr(VI)reduction were explored.The results revealed that the UAC-100 heterojunctions displayed more remarkable Cr(VI)reduction performance than the pristine UiO-66-NH2 and Ag2CO3,resulting from the improved separation of photo-induced electrons and holes.The enhanced photocatalytic activity of UAC-100 was further confirmed by the photoluminescence measurement,electrochemical analysis,and active species trapping experiments.After four cycles’experiments,the photocatalytic Cr(VI)reduction efficiency over UAC-100 was still over 99%,which exhibited that UAC-100 had excellent reusability and stability.Finally,the corresponding photocatalytic reaction mechanism was proposed and tested.

Hierarchical cobalt phenylphosphonate nanothorn flowers for enhanced electrocatalytic water oxidation at neutral pH

Cobalt-based phosphate/phosphonates are a class of promising water oxidation catalysts at neutralpH.Herein,we reported a facile hydrothermal synthesis of various nanostructured cobalt phe-nylphosphonates.It is found that the number of hydroxyl group of structure-directing reagent iscrucial for the construction of 3D hierarchical structures including hierarchical nanosheet flow-er-like assemblies and nanothorn microsphere.These samples were characterized by scanningelectron microscopy,transmission electron microscopy,X-ray diffraction,infrared,and X-ray pho-toelectron spectroscopy techniques.They can act as highly efficient electrocatalysts for the oxygenevolution reaction at neutral pH.Among these,hierarchical cobalt phenylphosphonate nanothornflowers present excellent performance,affording a current density of 1 mA cm^-2 required a smalloverpotential of 393 mV.This work offers a new clue to develop high-performance metal phospho-nate/phosphate catalysts toward electrochemical water oxidation.

Study on the catalyst in the decomposition reaction for BI organic waste water to adipic acid

The influences of kinds and level of catalyst, time of decomposition reaction on the distribution of dibasic acid and apparent yield of adipic acid were researched; the acidic washing waste water （BI waste water） producing from the equipment of cyclohexane oxidation by air was as stuff, the component of products by decomposed and oxidated in different conditions were analysed. It indicated that in the presence of cobalt salt the apparent yield of adipic acid was upto 10%-12% for the total BI waste water after the concentrated BI waste water refluxed for two hours, and then oxidated by nitric acid.

Antimicrobial and Photocatalytic Effect of Silicate and Silicone Hygienic Coatings

Antimicrobial and photocatalytic effect of silicate and silicone paints were tested. Silicate paints are based on water styrene-acrylic dispersion with mineral binder into form of potassium water glass. Silicone paints are based on water acrylic dispersion with silicone resin emulsion. Silicate and silicone paints were formulated with photocatalytic active nanooxides TiO2 and ZnO. Photocatalytic efficiency of coatings was measured as an absorbance change of organic dye Orange II solution at a wavelength of 485 nm. Antimicrobial properties of coatings were tested using agar plate methods. As test microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Penicillium chrysogenum and Aspergillus niger suspension （density 10^6 cells/mL） were used. The inhibition effect of tested coatings and inhibitory zones were evaluated after incubation. Coatings containing nanoparticles of titanium dioxide and zinc oxide showed antimicrobial activity against the test microorganisms. Whereas coating with zinc oxide nanoparticles successfully inhibited the growth of both bacteria and fungi, the photocatalytic nanoparticles of titanium dioxide inhibited bacteria but not fungi （weak inhibition was observed）.

Acetylcholinesterase liquid crystal biosensor for identification of AChE inhibitors by a reactivator

An improved acetylcholinesterase liquid crystal(LC) biosensor has been developed for the identification of organophosphates(OPs) by using a reactivator. When the acetylcholinesterases(AChEs) inhibited by different kinds of OPs are reactived by a reactivator, the catalytic activity of AChEs can be recovered with different activation efficiency because of the different phosphorylation structures formed in the inhibited AChEs. Accordingly, the reactived AChEs can catalyze the hydrolysis of acetylthiocholine to generate thiocholine product in different degrees, which will result in different catalytic growth of AuNPs and further form distinct orientational response of LCs. Based on such a reactivation mechanism, the AChE LC biosensor with a simple, rapid and visual procedure achieves an obvious identification of three OPs pesticides, methamidophos, trichlorfon and paraoxon, by using a pralidoxime reactivator.

Shape- and size-dependent catalysis activities of iron-terephthalic acid metal-organic frameworks

Precise control of the size and morphology of metal-organic frameworks(MOFs) presents an important direction for extending these inorganic-organic materials to many more advanced applications. However, because of the limit of the crystal-growth rule and mechanism, good-control of the size and morphology of MOFs remains challenging. In this contribution, an iron-terephthalic acid metal-organic framework with different shapes(octahedron, spindle and bipyramidal hexagonal) was easily and reproducibly synthesized via a solvothermal method. Sodium acetate and glycerol were used as modulators. Mechanism studies showed that the crystal nucleation rate and orientational growth both play important roles in determining the final shape of the MOFs. Further investigations showed that the as prepared MOFs exhibit shape-dependent catalytic activities, which means that MOFs can be designed to perform different catalytic functions. This investigation not only provides an effective guideline for the precise control of the size and morphology of metal-organic frameworks, but also extends MOFs to much more advanced applications in terms of catalyst chemistry.

Organocatalytic asymmetric allylic alkylation of sulfonylimidates with Morita-Baylis-Hillman carbonates

The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The corresponding allylic alkylation products were obtained in good yields with high stereoselectivities (up to 99% ee,89:11 dr).

Functionalized, carbon nanotube material for the catalytic degradation of organophosphate nerve agents

Recent world events have emphasized the need to develop innovative, functional materials that will safely neutralize chemical warfare （CW） agents in situ to protect military personnel and civilians from dermal exposure. Here, we demonstrate the efficacy of a novel, proof-of-concept design for a Cu-containing catalyst, chemically bonded to a single-wall carbon nanotube （SWCNT） structural support, to effectively degrade an organophosphate simulant. SWCNTs have high tensile strength and are flexible and light-weight, which make them a desirable structural component for unique, fabric-like materials. This study aims to develop a self-decontaminating, carbon nanotube-derived material that can ultimately be incorporated into a wearable fabric or protective material to minimize dermal exposure to organophosphate nerve agents and to prevent accidental exposure during decontamination procedures. Carboxylated SWCNTs were functionalized with a polymer, which contained Cu-chelating bipyridine groups, and their catalytic activity against an organophosphate simulant was measured over time. The catalytically active, functionalized nanomaterial was characterized using X-ray fluorescence and Raman spectroscopy. Assuming zeroth-order reaction kinetics, the hydrolysis rate of the organophosphate simulant, as monitored by UV-vis absorption in the presence of the catalytically active nanomaterial, was 63 times faster than the uncatalyzed hydrolysis rate for a sample containing only carboxylated SWCNTs or a control sample containing no added nanotube materials.