纳米TiO_2微胶粒的光化反应制备机理及量子尺寸效应

研究了由水相Ｔｉ３＋制备纳米极ＴｉＯ２微胶粒的光化反应机理及反应动力学，给出反应速率方程，讨论了ＴｉＯ２微胶粒的量子尺寸效应，经电镜测试ＴｉＯ２粒子的直径为１５～２５ｎｍ，反应过程中由气相色谱仪监测生成物Ｈ２。     

NO^—2离子的光催化反应研究（Ⅱ）

研究了ＮＯ＾－２离子在ＴｉＯ２表面的光催化反应,结果表明,体系ｐＨ值升高及Ｃｒ,Ｃｌ＾－,ＳＯ＾２－４离了的加入均对ＮＯ＾－２离子在ＴｉＯ２表面的暗态吸附产生抑制作用,而ＮＯ＾－２在ＴｉＯ２表面的光照反应转化率则随ｐＨ值的升高出现先减小后增大的总体变化趋势。     

α—Ti（HPO4）2·H2O的制备方法研究

本文介绍了一种快速制备α－Ｔｉ（ＨＰＯ４）２·Ｈ２Ｏ晶体的新方法，该法以硫酸钛为原料，先制得稳定的Ｔｉ（Ｏ２）ＯＨ（Ｈ２Ｏ４）４＾＋配离子溶液，将其加入磷酸溶液后，加热使Ｔｉ（Ｏ２）ＯＨ（Ｈ２Ｏ）４＾＋分解，逐步释放出钛与磷酸反应，在２小时内制得α－Ｔｉ（ＨＰＯ４）２·Ｈ２Ｏ。在实验温度１２０－１５５℃范围内，此法几乎不受温度和时间的影响。     

SO4^2—／TiO2,PO4^3—／TiO2,BO3^3—／TiO2系列固体酸的酸性,结构和晶 …

制备了ＳＯ４＾２－／ＴｉＯ２（Ｉ）、ＰＯ４＾３－／ＴｉＯ２（Ⅱ）、ＢＯ３＾３－／ＴｉＯ２（Ⅲ）系列固体酸。用ＩＲ、Ｒａｍａｎ光谱对该系列固体酸进行结构表征,结果表明ＳＯ４＾２－与ＴｉＯ２表面的结合为螯合式双配位结构和共价硫酸盐共存,ＰＯ４＾３－与ＴｉＯ２表面的结合为桥式三配位结构,ＢＯ３＾３－与ＴｉＯ２表面的结合为单齿单配位结构和螯桥混合式三配位结构共享。用由溶液中正胺的吸附等温线测定固体表面酸度     

灭多威的光催化降解动力学研究

研究了农药灭多威在ＴｉＯ２光催化下的降解产物，反应动力学及影响降解速度的因素，灭多威在ＴｉＯ２催化下１０ｍｉｎ内可被完全转换为无机物而失去毒害作用，ＩＲ研究表明，灭多威的分解产物ＮＨ＾＋４，ＳＯ＾２－４和ＣＯ２，其分争过程中准一级反应，除铜和氯离子体低浓度时有促进作用，而高浓度为阻碍作用外，大部分阴，阳离子对降解均有不利影响。     

SO(2-)4/Ti-Al-O固体超强酸的酸强度及催化性能

ＳＯ４＾２＾－／Ｔｉ－Ａｌ－Ｏ型固体超强度酸可用于邻苯二甲酸二辛酯（ＤＯＰ）的合成，当Ｔｉ／Ａｌ原子比为２时，催化性能优于ＳＯ４＾２＾－／ＴｉＯ２，且催化剂的制备条件对其酸强度，表面积和催化活性有较大的影响。使用ＴＰＤ技术对催化剂的酸强度分布进行了表征，发现在ＳＯ４＾２＾－／Ｔｉ－Ａｌ－Ｏ型固体超强度酸中，存在着三种酸中心（弱酸，中等强度酸和超强酸），中等强度的酸中心浓度与ＤＯＰ合成的催化活性有有     

SO^2—4／TiO2和SO^2—4／Fe2O3固体超强酸研究

用ＸＲＤ、ＴＧ－ＤＴＧ、ＳＥＭ和化学分析等手段研究了浸渍Ｈ２ＳＯ４的无定形ＴｉＯ２和Ｆｅ２Ｏ３在焙烧过程中的晶化、相变、失水及失硫情况，总结出ＳＯ＾２－４／ＭｘＯｙ型固体超强酸具有与ＳＯ＾２－４／ＺｒＯ２体系相同的形成规律。用ＩＲ光谱和常温正戊烷异构化反应对ＳＯ＾２－４／ＴｉＯ２／Ｆｅ２Ｏ３的超强酸性进行了表征，表明它们与ＳＯ＾２－４／ＺｒＯ２体系具有相似的表面酸位结构，无水状态主要为Ｌ酸位，吸水     

SiO2,Al2O3上涂载TiO2,ZrO2,La2O3制备Pd催化剂的研究

采用浸渍法制备了Ｌａ２Ｏ３，ＴｉＯ２，ＺｒＯ２以单层状态分散在ＳｉＯ２，Ａｌ２Ｏ３上的改性载体。用ＸＰＳ求得它们的最大单层分散阈值为：０．２２ｇＬａ２Ｏ３／１００ｍ＾２ＳｉＯ２，０．２７ｇＬａ２Ｏ３／１００ｍ＾２Ａｌ２Ｏ３，０．０４ｇＴｉＯ２／１００ｍ＾２ＳｉＯ２，０．０３６ｇ ＴｉＯ２／１００ｍ＾２Ａｌ２Ｏ３，０．０７ｇＺｒＯ２／１００ｍ＾２ＳｉＯ２，０．０８ｇＺｒＯ２／１００ｍ＾２Ａｌ２Ｏ３．     

SO4^2—TiO2—Hβ—Al2O3催化剂的制备及催化性能研究

以Ｈβ沸石为，通过ＴｉＯ２改性及硫酸铵处理制备了ＳＯ４＾２－－ＴｉＯ２－Ｈβ－Ａｌ２Ｏ３催化剂，并由ＸＲＤ、ＸＰＳ、ＮＨ３－ＴＰＤ、ＦＴＩＲ及化学吸附等手段考察了不同焙烧温度对该催化剂表面性质、酸性及催化性能的影响。结果表明；适宜的焙烧温度使ＳＯ４＾２－－ＴｉＯ２－Ｈβ－Ａｌ２Ｏ３的酸量大幅度增加，强酸比例增大，并产生部分增强酸中心，高强度的酸性中心中，以Ｌ酸中心为主；５５０℃焙烧的样品能使沸石表     

添加非金属元素Si对固体超强酸SO^2—4／TiO2的改性研究

采用共沉淀法引入Ｓｉ对ＳＯ＾２－４／ＴｉＯ２进行改性，制得了ＳＯ＾２－４／Ｔｉ－Ｓｉ－Ｏ系列固体超强酸，试样经ＩＲ，ＳＥＭ，ＸＲＤ表征和低温正戊烷异构化活性测试，发现超强酸中心是硫酸根离子与金属原子Ｔｉ结合形成的双配位螯全结构，在超强酸性的榈中ＴｉＯ２均呈锐钛矿晶型。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.