化学气相沉积法制备的TiO_2薄膜的光学性质及其应用

以ＴｉＣ１４为源物质采用常压化学气相沉积法制备了ＴｉＯ２薄膜。用紫外光谱测定了膜的透过率,进而计算出折光率、消光系数、光学带隙能等光学参数。结果发现,在不同气流量、沉积温度为１００～２５０℃的条件下制备的ＴｉＯ２膜,其折射率在２．１６～２．８２范围内,消光系数在０．０４×１０－３～６．７０×１０－３范围内,光学带隙能在２．８～３．０８ｅＶ范围内。在光催化作用下,ＴｉＯ２膜用于处理苯酚溶液,苯酚的转化率高达５４．０５％。关键词##4化学气相沉积（ＣＶＤ）;;沉积率;;折光率;;消光系数;;光催化     

TiO2纳米粒子膜表面性质的研究

ＴｉＯ_２纳米粒子膜在光催化降解大气和水中的污染物［１］、光电转换［２］、光致变色［３］等方面有广阔的应用前景,近年来受到了科学界的高度重视．研究表明,膜的表面性质对如上应用有着重要影响．本文采用等离子体化学气相沉积法（ＰＥＣＶＤ法）［４］制备了ＴｉＯ２的纳米粒子膜,分别采用ＴｉＣｌ４等离子体或Ｏ２等离子体处理膜表面,获得两种不同表面性质的ＴｉＯ２纳米粒子膜;并利用表面光电压谱（ＳＰＳ）和电场诱导表面光电压谱（ＥＦＩＳＰＳ）技术对膜的表面性质进行具体分析,探讨了其在光催化领域的可能应用．１实验部…     

制备条件对二氧化钛薄膜性能的影响(英文)

用低压化学气相沉积法制备ＴｉＯ２薄膜。研究表明,水的分压、沉积温度、基片材料均对沉积速率有影响。在硅片上镀膜,沉积温度相同而退火温度不同,则薄膜结构亦不同。当退火温度高于８５℃时,薄膜为纯金红石薄膜。     

TiO2陶瓷顶层膜的化学气相淀积生长研究

以ＴｉＣｌ和Ｔｉ（ＯＣ４Ｈ９）４为源物质采用热化学气相淀只（ＣＶＤ）法及射频ＰＣＶＤ法在多孔α－Ａｌ２Ｏ３陶瓷衬底上淀积生长ＴｉＯ２薄膜，观测ＴｉＯ２膜的生长方式、生长速率以及结构和表面形貌等，讨论其生长机制，评价ＣＶＤ改性生长的顶怪ＴｉＯ２陶瓷膜的气体渗透性。     

溶胶—凝胶法制备负载型TiO2膜的研究

本研究采用溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）法制备了负载型ＴｉＯ２膜，并采用ＳＥＭ、压汞等实验手段对Ｔｉ（ＯＨ）４溶胶和ＴｉＯ２膜进行了表征。实验表明：Ｔｉ（ＯＨ）４溶胶制备过程中Ｈ２Ｏ／Ｔｉ＾４＋、Ｃ２Ｈ５ＯＨ／Ｔｉ＾４＋的比值，溶胶在支承管上浸涂的时间、次数以及凝胶煅烧升温速度和煅烧温度均是制备负载型ＴｉＯ２膜的重要因素。最终制得一种无裂纹、２０μｍ厚、孔径分布在５０￣３００ｎｍ之间的负载型ＴｉＯ２     

利用TiO_2薄膜光催化降解苯酚(英文)

利用化学气相沉积法制备ＴｉＯ_２Ｗ薄膜,在光催化下降解苯酚溶液。研究结果表明,薄膜沉积条件与降解速率有关,且用硅片作底物,薄膜为锐态晶型时其降解苯酚速率最高。利用光电催化比只用光催化降解苯酚速率高约１０％。用紫外光照射３０分钟,苯酚最大可转化７４％。     

纳米尺度TiO2聚苯胺多孔膜电极光电化学研究

用光电流作用谱，光电流－电势图等光电化学方法研究了ＴｉＯ２／聚本胺复合多孔膜电极在不含氧化还原和含有没氧化还原对体系中的光电转换过程。结果说明，ＴｉＯ２／聚苯胺复合多孔膜电极为双层ｍ－型半导体结构，ＴｉＯ２多孔膜的禁带宽度为３．２ｅＶ，外层聚苯胺膜的禁带宽度为２．８８ｅＶ。     

工作气氛和偏压对含铁聚合物杂混薄膜制备的影响

采用等离子体增强金属有机化合物化学气相沉积（ＰＥＭＯＣＶＤ）工艺，在氧化性气氛（Ｏ２）和非氧化性气氛（Ｈ２、Ａｒ）中制备了含铁聚合物杂混薄膜。探讨了工作气氛和偏压对膜密度、沉积速率及其分布的影响。     

MoO3／（Tio2—SiO2）催化剂的表面分散状态及催化性能的研究

用气相流动吸附法制备复合载体，用浸渍法制备ＭｏＯ３（ＴｉＯ２－ＳｉＯ２）催化剂，应用ＬＲＳ和ＴＰＲ技术研究ＭｏＯ３在复合载体ＴｉＯ２－ＳｉＯ２表面的分散发现ＴｉＯ２在ＳｉＯ２表面的分散可增强ＭｏＯ３与载体之间的相互作用，提高ＭｏＯ３在载体表面的分散阈值。     

γ射线辐照超细铂催化剂的载体效应

用γ射线辐射法制备了铂溶胶和粒径为５ｎｍ的超细铂粉,采用机械混合法和溶胶－凝胶法制备了一系列不同载体的超细铂催化剂,不同载体对提高ＣＯ氧化活性的顺序为：ＭｇＯ〉γ－Ａｌ２Ｏ３≥ＺｒＯ２〉ＴｉＯ２〉ＳｉＯ２,其中,由溶胶－凝胶法制备的０．１％Ｐｔ／ＳｉＯ２和０．１％Ｐｔ／ＴｉＯ２的经表面积大,Ｐｔ分散度高,但活性最差,ＸＰＳ结果表明部分表面Ｐｔ＾０和ＴｉＯ２作用生成了ＰｔＯ和Ｔｉ２Ｏ３,并且Ｐｔ的分     

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.