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1.
烷基胺和醇胺在层状磷酸锆中的嵌入研究   总被引:2,自引:0,他引:2  
从制备层柱磷酸盐的要求出发考察了烷基胺和醇胺在层状α-Zr(HPO4)2·H2O(α-ZrP)中的嵌入及其对该层状磷酸盐结构和性质的影响。发现层板剥离度与有机胺种类及加入量有关;HPO4^2-的水解程度主要取决于胺分子的碱性和层板剥离状况;已剥离的层板是介稳定的,放置后会重新有序化并发生相变。XRD及结构模型近似计算结果表明,在饱和嵌入量时,烷基胺和醇胺在α-ZrP层间呈双层排列。样品在空气中长时  相似文献   

2.
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。  相似文献   

3.
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(H2O)+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。  相似文献   

4.
层状磷酰锆的合成与性质研究   总被引:1,自引:0,他引:1  
用回流、水热晶化和HF沉淀三种方法制备了α-Zr(HPO4)2.H2O(α-ZrP)晶体。HF沉淀法制备的α-ZrP晶体尺寸最大。层板有序度最高,水热法次之,回流法最差,水热法合成的α-ZrP层析本身的结晶度最高。  相似文献   

5.
制得了二丁胺甲基膦酸-亚磷酸氢锆Zr(HPO3)2-x.(O3PCH2NBu2).H2O(x=0.8,0.6,0.5,0.4,0.35),用溴化苄季铵化,得部分季铵化产物,溴化苄基二丁铵甲基膦酸-二丁胺甲基膦酸-亚磷酸氢锆Zr(HPO3)2-x.(O3PCH2NBu2)x-y.(O3PCH2N^+Bu2.CH2Ph.Br^-).H2O(y<x),用作相转移催化剂,对液/液或固/固/液相转移催化的取  相似文献   

6.
研究了二(2-乙基已基)磷酸(DEHPA)-磺化煤油体系从氟碳铈矿氧化焙烧-硫酸浸出液中萃取Ce^4+的机制,发现水相中F^-和Ce^4+同时被萃入有机相,通过斜率法和研究平衡有机相中cF-/cCd^4+和初始水相酸度、初始水相氟离子浓度、有机相浓度之间的关系,推测出F^-和Ce^4+以CeF2A2形式被DEHPA萃入有机相。  相似文献   

7.
唐颐  徐金锁  高滋 《催化学报》1998,19(4):354-359
详细研究了有机胺品种、层板预撑态、水解度以及Cr加入量等制备因对氧化铬层柱磷酸铬结构和性能的影响,用乙胺胶体化法制备的氧化铬层柱磷酸锆比表面积可高达482m^2/g,而孔径集中在2.6nm附近,层板胶体化时表面磷酸根的知度水有利于提高支柱产品的比表面和形成规整的平板型层间孔,用TG,IR,XRD和N2吸附等温线方法研究了氧化铬柱了的形成过程和热稳定性,异丙醇脱水和异丙苯裂解反应结果表明,氧化铬层柱  相似文献   

8.
α-磷酸锆层柱材料的制备、表征及其催化羰基化性能   总被引:4,自引:0,他引:4  
采用配体4-CH3SC6H4NH2插层的α-磷酸锆为插层主体,将Rh63+引入层状材料的层析之间制备了新型层柱催化材料Zr(HPO4)1.70(CH3SC6H4NH2)1.09(PO4)0.30Rh0.10.5.52H2O,其是距为2.36变为1.56nm,结晶度有所下降。  相似文献   

9.
Zr(SO4)2·4H2O的层状结构、插层及催化性能   总被引:19,自引:1,他引:19  
李峰  何静  杜以波  孙鹏  Evans  段雪  王作新 《催化学报》1998,19(6):583-587
利用XRD,TPDE,PED和TG-DTA等为主要研究手段,深入分析了Zr(SO4)2·4H2O的层状结构特性和插层性能,并以乙酸与乙二醇单醚的酯化反应普目标反应考察了其催化性能。研究结果表明:Zr(SO4)2·4H2O是一种具有中等强度酸性的层状化合物,位于层间的结晶水是产生B酸中心的来源;有机胺类分子具有较强的插层能力,胺的插入可将层板撑开并使层间距增大,从而进一步证实存在层间结晶水所产生的B  相似文献   

10.
本文研究了Cu(Ⅱ)-PEG(聚乙二醇-2000)-Zincon(锌试剂)-(NH4)2SO4体系的析相光度法并应用于测定Cu(Ⅱ)。最宜酸度为pH5.5~8.5(KH2PO4-K2HPO4)缓冲溶液)其络合物的最大吸收位于610nm,表观摩尔吸光系数为4.0×10^4L.mol^-1.cm^-1,Cu(Ⅱ)浓度在0~1.5mg/L范围内服从比尔定律,铜与Zincon形式组成为1:2的稳定的蓝色络  相似文献   

11.
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%.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
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.  相似文献   

18.
19.
《Tetrahedron》2014,70(21):3377-3384
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.  相似文献   

20.
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.  相似文献   

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