用天然钙质膨润制取有机膨润土

以天然钙质膨润土为原料,将膨润土原矿脱除杂质制成膨润土悬浮液,然后以无水碳酸钠和十八烷基三甲基氯化铵为活性剂进行纳化,季胺盐活性阳离子表面活化及粉磨等工序,制得了有机膨润土。探索了适宜的活化工艺,所得产物在有机溶剂中可膨胀２０￣２５倍,粘度达０．９Ｐａ．ｓ以上,质量合乎部颁标准。     

用天然钙质膨润土制取有机膨润土

以天然钙质膨润土为原料,将膨润上原矿脱除杂质制成膨润土悬浮液,然后以无水碳酸钠和十八烷基三甲基氯化铵为活性剂进行钠化,季胺盐活性阳离子表面活化及粉磨等工序,制取了有机膨润土。探索了适宜的活化工艺,所得产物在有机溶剂中可膨胀20－25倍,粘度达0．9Pa．s以上,质量合乎部颁标准。     

膨润土碱熔活化合成4A分子筛的研究

以天然膨润土为原料,采用高温碱熔水热法合成4A分子筛。探讨了活化温度、SiO2/Al2O3、Na2O/SiO2、H2O/Na2O等工艺条件对4A分子筛结构与性能的影响。结果表明,最佳的活化温度为600℃;物料经此温度活化后,调节组成为SiO2/Al2O3=1.5、Na2O/SiO2=3与H2O/Na2O=50,于90℃反应6小时可以得到质量较好的4A分子筛,其产品的晶形规整,晶粒均小于2μm,钙离子交换容量可达到314mg CaCO3/g。     

不同活化方法对天然硅铝矿物活化及分子筛合成效果的影响

选取了高岭土、累托土、蒙脱土和伊利石四种天然硅铝矿物,采用热活化、碱熔活化、亚熔盐活化及拟固相活化四种方法对上述四种矿物分别进行活化,对比了不同活化方法对天然硅铝矿物活化效果的影响。结果表明,亚熔盐活化及拟固相活化都具有良好的活化效果,而且能耗较低,明显优于热活化和碱熔活化。其中,拟固相活化由于能耗更低且更有利于实现工业操作,因此,是最具发展前景的天然硅铝矿物活化方法。对比四种天然硅铝矿物,高岭土、累托土及蒙脱土的晶相结构更容易被解聚,而伊利石稳定性更高,经亚熔盐活化及拟固相活化后,活化产物中也只有极少量的高反应活性的硅、铝物种,因此,伊利石不是理想的分子筛合成原料。     

碱熔-蒸馏-滴定法测定萤石中的氟化钙含量

采用碱熔-蒸馏-滴定法测萤石中氟含量,计算得到氟化钙含量.萤石试样首先用碳酸钠碱熔消解,然后经硫酸-水蒸气蒸馏分离氟,以茜素磺酸钠作指示剂,用硝酸钍溶液滴定测出其中氟含量,并计算得到氟化钙含量.利用X射线衍射光谱(X RD)法验证了萤石中氟的存在形式,并通过实验确定了碳酸钠使用量、硫酸溶液加入量、蒸馏温度和蒸馏时间等的...     

导电聚苯胺/钙基膨润土复合材料的制备

采用插层聚合法制备了导电聚苯胺/钙基膨润土、聚苯胺/有机化膨润土复合材料.以电导率为考核指标,通过正交设计优化了苯胺的加入量、反应温度和反应时间等参数.结果表明,苯胺的加入量影响较显著,反应温度对聚苯胺/有机化膨润土复合材料影响较聚苯胺/钙基膨润土体系明显,反应时间的延长,有利于聚苯胺/有机化膨润土复合材料电导率的提高.聚苯胺/钙基膨润土复合材料制备的最佳工艺条件为:苯胺加入量为70%,反应温度为0℃,反应时间为6 h;聚苯胺/有机化膨润土复合材料制备的最佳工艺条件为:苯胺加入量为70%,反应温度为室温,反应时间为8 h.利用红外光谱(FT-IR)、X射线衍射(XRD)和四探针技术表征了材料的组成、结构和性能.结果表明:膨润土经有机化后,晶面间距增大较多;苯胺单体与钙基膨润土插层聚合后,膨润土晶面间距增大不多;苯胺单体与有机化膨润土复合后,破坏了膨润土的晶格结构,形成了混杂复合体系,电导率达10-3S.cm-1.     

超级活性炭的合成及活化反应机理

以石油焦为原料,采用碱熔活化法合成出具有超高比表面的超级活性炭.借助XRD、TG DTA、N2吸附实验等手段,对其结构与性能进行了表征.同时,设计原位TG DTA测试技术、反应快速终止技术,对超级活性炭合成机理进行了考察,提出了两段活化反应机理,即中温径向活化机理和高温横向活化机理.发现K2O、－O－K＋以及－CO－2K＋是径向活化为主的中温活化段的活化剂活性组分,而处于熔融状态的K＋O－、K＋则是横向活化为主的高温活化段的催化活性组分.并发现径向活化是超级活性炭形成发达微孔分布的主要途径,也是控制超级活性炭微孔分布的主要手段.而高温横向活化机理则是导致超级活性炭形成大孔的主要途径.高温横向活化与中温径向活化一起构成石油焦基超级活性炭形成的主要机理.     

以催化裂化废催化剂粉合成超细 Y 型分子筛

 针对催化裂化 (FCC) 废催化剂细粉带来的环境污染和未开发利用的现状, 以此为原料合成了小晶粒 Y 型分子筛, 并采用 X 射线衍射、扫描电镜、29Si和27Al 固体核磁共振和激光粒度分析等技术对样品进行了表征. 结果表明, 以 FCC 废催化剂细粉为原料可以合成粒径为 200 nm 左右的 Y 型分子筛, 且制备过程中原料的活化方法和导向剂对所得样品结构影响很大. 对原料采用碱熔活化, 并在合成体系中加入导向剂, 所得 Y 型分子筛的相对结晶度提高, 比表面积增大, 粒度减小.     

通过RAFT法制备聚合物/膨润土杂化材料

通过可逆加成-断裂链转移(RAFT)自由基聚合方法合成了聚合物/膨润土(蒙脱石)杂化材料. 以乙基黄原酸基膨润土为链转移剂, AIBN为引发剂, 在环己酮溶液中, 通过甲基丙烯酸甲酯的RAFT自由基聚合, 得到了一系列的聚合物/膨润土杂化材料. 并用FT-IR, NMR, SPM, TG, GPC等分别对产物的微观结构、热性能、有机物含量以及分子量和分子量分布进行了表征和测试.     

碳酸钠催化合成阿司匹林

利用水杨酸和乙酸酐作为反应物,碳酸钠为催化剂,催化合成阿司匹林.通过考察催化剂用量、反应物物质的量比、反应时间等因素对合成阿司匹林产率的影响,最终确定使用碳酸钠合成阿司匹林的最适条件为:水杨酸的用量为0.1mol,乙酸酐的用量为0.175mol,使用催化剂碳酸钠的质量为1.4g,反应进行时间为60min,在此条件下阿司匹林的产率可达到74.3%.此实验采用的操作方法简便、反应条件易于控制、反应生成的副产物少,实验后处理简捷,实验安全性能高.催化剂碳酸钠催化效率高、稳定性好、来源广泛、经济易得是符合绿色化学宗旨的理想催化剂.     

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%.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.