氧化锌催化剂在碳酸二甲酯合成中的应用研究

用低热固相配位化学反应方法、分析纯ZnO表面改性、均相沉淀法、溶胶-凝胶法、并流沉淀法和固体研磨法6种方法制备了ZnO催化剂.对这6种ZnO催化剂进行了XRD和SEM表征,筛选出最好的催化剂;比较了它们对DMC合成的活性大小的影响.结果表明:在尿素3 g,甲醇120mL,催化剂占整个反应物质量的6%,反应温度170～180℃,压力2.0～2.4 MPa,时间8 h条件下,ZnO(D)的催化活性最高,DMC的收率达到6.10%,尿素转化率为77.83%;用不同方法制备得到的ZnO催化活性顺序为ZnO(D)＞ZnO(F)＞ZnO(C)＞ZnO(A)＞ZnO(B)＞ZnO(E).     

Iron Nitrate/TEMPO: a Superior Homogeneous Catalyst for Oxidation of Primary Alcohols to Nitriles in Air

A highly practical, one‐step, facile synthesis of aromatic, heteroaromatic, allylic and aliphatic nitriles from primary alcohols catalyzed by ferric nitrate [Fe(NO₃)₃⋅9H₂O] in the presence of TEMPO, aqueous ammonia and air at room temperature is described.

     

Synthesis of Graphene Oxide/Iron Oxide/Au Nanocomposite for Quercetin Delivery

This study focused on developing a superparamagnetic graphene oxide-based nanocomposite consisting of iron oxide (IO) and gold nanoparticles for quercetin delivery. For this purpose, the structure and morphology of the designed nanocomposite (GO/IO/Au) were investigated by several characterization methods such as fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, vibrating-sample magnetometer (VSM) analysis, field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM). Then, the biocompatibility of the synthesized nanocomposite was studied by Brine shrimp Artemia lethality assay, red blood cell hemolysis assay, and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. Moreover, the GO/IO/Au nanocomposite efficiency as an anticancer drug delivery system was evaluated in vitro conditions. The results showed that the designed nanocomposite is highly biocompatible and possesses a favorable magnetization (M_s?=?29.2 emu.g^?1) making it a good candidate for biomedical applications. Also, it was confirmed that GO/IO/Au nanocomposite is a potent drug carrier that can effectively deliver quercetin to cancer cells.

     

Direct Amide Synthesis from Alcohols and Amines by Phosphine‐Free Ruthenium Catalyst Systems

Amides are synthesized directly from alcohols and amines in high yields using an in situ generated catalyst from easily available ruthenium complexes such as the (p‐cymene)ruthenium dichloride dimer, [Ru(p‐cymeme)Cl₂]₂, or the (benzene)ruthenium dichloride dimer, [Ru(benzene)Cl₂]₂, an N‐heterocyclic carbene (NHC) ligand, and a nitrogen containing L‐type ligand such as acetonitrile. The phosphine‐free catalyst systems showed improved or comparable activity compared to previous phosphine‐based catalytic systems. The in situ generated catalyst from [Ru(benzene)Cl₂]₂, an NHC ligand, and acetonitrile showed excellent activity toward reactions with cyclic secondary amines such as piperidine and morpholine.     

氧化锡催化合成尼泊金戊酯

以对羟基苯甲酸和戊醇为原料,氧化锡为催化剂,甲苯为带水剂,合成了尼泊金戊酯,探讨了最佳反应条件,酯收率可达到90％,具有一定的应用价值。     

从废弃甲醇合成催化剂中回收氯化亚铜和氧化锌的新工艺研究

国内甲醇产能约3000万t/a,可综合利用的废弃甲醇合成催化剂约3000t/a,笔者研究了一种从废弃甲醇合成催化剂中回收氯化亚铜和氧化锌的新工艺.简述了回收氯化亚铜和氧化锌的制备原理;论述了废弃催化剂的预处理工艺条件以及浸取制备氯化亚铜和氧化锌的工艺条件.研究结果表明:回收的氯化亚铜产品质量可达到GB1619-79中标...     

Eco-Friendly Synthesis of Graphene Oxide Reinforced Hydroxypropyl Methylcellulose/Polyvinyl Alcohol Blend Nanocomposites Filled with Zinc Oxide Nanoparticles for High-k Capacitor Applications

Polymer/inorganic nanocomposites comprising of hydroxypropyl methylcellulose and polyvinyl alcohol as a polymer matrix and unique combination of graphene oxide and zinc oxide nanoparticles as fillers have been prepared using colloidal processing technique and characterized using various analytical methods. The dielectric properties of the nanocomposites are investigated using impedance analyzer. The nanocomposites show improvement in the dielectric properties compared to hydroxypropyl methylcellulose/polyvinyl alcohol (50/50) blends, which results from the homogeneous dispersion of fillers into the polymer matrix. The results indicate that these nanocomposites have a potential to meet the technological demands of high-k dielectrics and/or embedded capacitors.     

Modified Zinc Oxide for the Direct Synthesis of Propylene Carbonate from Propylene Glycol and Carbon dioxide

A series of modified zinc oxide catalysts were prepared and their catalytic activities were evaluated by the direct synthesis of propylene carbonate from propylene glycol and carbon dioxide in the presence of acetonitrile, which acted as not only the solvent but also the dehydrating reagent in the reaction. The reusability test indicated that the modified catalysts had the high stability. Ammonium carbonate was added into the reaction to significantly elevate the selectivity of propylene carbonate.     

纳米氧化锌催化合成松香甘油酯的研究

首次采用纳米粒子氧化锌作为松香与甘油酯化反应的催化剂,实验讨论了催化剂、反应温度、反应时间和醇酸比对反应工艺的影响,并在此基础上进行正交试验,得出反应的最佳工艺条件为:在氮气的保护下,用松香与过量20%质量分数的甘油酯化反应的反应温度为250°C、反应时间5h、催化剂0.25%(以松香量为基准)、甘油与松香的质量比为:12.19∶100。在最佳工艺条件下,进行了稳定性实验,得到的松香甘油酯的酸值为:7.3,软化点:86.9°C,产率为94.5%,色泽:加纳色级8,在苯中溶解度(1∶1):清,符合136#松香甘油酯质量指标。纳米氧化锌催化松香酯化相对目前工业常用的ZnO催化剂而言,缩短了反应时间、降低了反应温度,有应用价值。     

In Situ Synthesis of Ultrahigh Molecular Weight Polyethylene/Graphene Oxide Nanocomposite Using the Immobilized Single-site Catalyst

We address the immobilization of single-site catalyst on the graphite oxide (GO) surface using methylaluminoxane. Ethylene polymerization was performed using the immobilized catalyst and the nanocomposite of ultrahigh molecular weight polyethylene (UHMWPE)/GO with less entanglement density was obtained. It was observed that the drawability, mechanical and thermal properties of the produced polymer significantly are affected by the anchoring of polymer chains to the GO nanosheets. The orientation and location of crystalline lamellae and nanosheets were verified by microscopic techniques. Besides, X-ray analysis demonstrated the dispersion of GO within the UHMWPE phase and crystallinity of UHMWPE/GO nanocomposites enhanced during drawing process.     

Synthesis of Molybdenum Oxide Nanohybrids as Efficient Catalysts in Oxidation of Alcohols

Novel layered materials based on molybdenum oxide have been synthesized using three amino-carboxylate ligands; terephetalic acid, p-aminobezoic acid and diaminobenzene. On the basis of X-ray diffraction, scanning electron microscopy, thermogravimetry, and infrared results, the insertion of organic ligands into the interlayer space of molybdenum oxide has been proposed. Moreover, the influence of organic guests on the oxide structure and also their catalytic performance are discussed. Furthermore, fabrication of the nanostructured molybdenum oxide is achieved by calcinations of these hybrid materials at 600 °C. Somewhat oriented nanoplatelets are viewed with different catalytic activity.     

Nanoarchitectonics of Cerium Oxide/Zinc Oxide/Graphene Oxide Composites for Evaluation of Cytotoxicity and Apoptotic Behavior in HeLa and VERO Cell Lines

Journal of Inorganic and Organometallic Polymers and Materials - Using the ultrasonic approach, we produced a morphology involving a cerium oxide/ zinc oxide/graphene oxide nanocomposite-based...     

A Radical Pathway for Direct Substitution of Benzyl Alcohols with Water‐Soluble Copper Catalyst in Water

We have developed a novel strategy for the direct substitution of benzyl alcohols with anthranilic acids using water‐soluble copper catalysts through a radical pathway in water, which offers efficient and environmentally friendly N‐, S‐, and C‐benzylations under neutral conditions. Radical scavengers strongly inhibited the benzylation. Radical clock experiments using α‐cyclopropylbenzyl alcohol were conducted to observe the rapid isomerization of the cyclopropylmethyl radical to the allylmethyl radical. Hammett plots could be fitted to a two‐parameter Hammett relationship containing both radical and polar contributions [log (k_X/k_H)=−1.24 σ^.–0.38 σ, R²=0.99]. The relative parameter ρ^./ρ of 3.3 suggested that these reactions involved a strong radical character with minor polar influence at the transition state.