氯化钙在粗孔硅胶上的单层分散及其氨吸附——乙醇溶液浸渍法的影响

利用乙醇溶液浸渍法将氯化钙担载于粗孔硅胶上,通过焙烧或微波加热使氯化钙在载体表面分散,研究了不同条件下氯化钙在粗孔硅胶上的单层分散及其氨吸附量的影响,并将结果与水溶液浸渍法进行了比较.结果表明,乙醇溶液浸渍样品的适宜焙烧温度为500℃,对应的氯化钙单层分散阈值在0.4-005g/g之间,而水溶液浸渍样品的最大单层分散容量小于0.4g,g,乙醇溶液浸渍法较水溶液浸渍法更适合在粗孔硅胶上担载氯化钙.乙醇浸渍微波法与焙烧法相比,微波法能显著提高氯化钙在硅胶上的单层分散.氨吸附实验进一步验证了上述结论,担载量为0.5g/g的乙醇浸渍微波样品的氨吸附量最大,在35℃达到0.654g,g.乙醇溶液浸渍样品的氨吸附分离能力明显大于水溶液浸渍样品.     

CuCl改性Y型分子筛的CO吸附性能研究

利用自发单层分散原理,讨论了在NaY,NH4Y,CuY分子筛上CuCl分散改性情况,并对所得到的改性分子筛进行了CO吸附性能研究。实验结果表明,在低CuCl担载量时,CuCl可在这三种载体表面达到原子水平分散,其分散容量分别为0.58g/gNaY,0.68g/gNH4Y和0.41g/gCuY。由于CO与Cu^+可生配位化合物,经CuCl改性的Y型分子筛对CO显示出较高吸附性能。其中,0.6gCuCl/gNH4Y分子筛表现出最高的CO吸附容量,在室温、常压下可达123mL/gNH4Y.     

CuHY分子筛中铜离子的分布与吸附脱硫性能

采用等体积浸渍法制备具有不同Cu担载量的CuHY 分子筛吸附剂. 用X射线衍射(XRD)、比表面积(BET)和氨程序升温脱附(NH3-TPD)技术对分子筛吸附剂进行了表征, 并测定了CuHY 分子筛吸附剂在含二苯并噻吩(DBT)模拟柴油中的吸附脱硫性能; 通过多晶XRD确定了Cu2+在Cu8HY 分子筛笼内的结构与分布. 实验结果表明, 分子筛的骨架结构没有发生改变, 部分Cu2+进入Y型分子筛笼内, 分子筛样品强酸中心有所减少, 中强酸中心有所增加; 进入Y型分子筛笼内的Cu2+, 一部分处于β 笼的SI' 位, 另一部分位于分子筛超笼中的SIII位上, 并与笼内的水分子配位. 处于超笼中的SⅢ位Cu2+对模拟柴油中的DBT分子具有吸附作用, 是吸附脱硫的中心. 而当模拟柴油中存在萘时, 与DBT分子会产生竞争吸附.     

新型空气取水复合吸附剂在沙漠气候下的吸附性能实验研究

提出了一种由粗孔球形硅胶和氯化钙组成的新型复合吸附剂SiO2穢H2O穣CaCl2。介绍了这种吸附剂的配制方法,分析了它吸附湿空气中水蒸气的原理。模拟我国塔克拉玛干沙漠地区高温干燥的气候特点:在空气温度恒为35℃、相对湿度为30%的条件下,对不同CaCl2含量的复合吸附剂和粗孔球形硅胶、细孔球形硅胶、分子筛13X进行了吸附解吸对比实验。实验表明,这种复合吸附剂的平衡吸附量we最大可达0.263kg H2O/kg干吸附剂,是粗孔球形硅胶的5.6倍、细孔球形硅胶的3.4倍、分子筛13X的1.17倍。通过对比分析它们的吸附解吸速度曲线表明,这种复合吸附剂的吸附量大、吸附速度快、解吸速度快。这种复合吸附剂在解吸温度80℃,可解吸97%以上的吸附量。因此,可用太阳能加热解吸,是一种理想的取水用吸附剂。     

微波辐射法合成SAPO-5分子筛中硅铝比对产物结晶度和甲苯吸附性能的影响

采用硅溶胶作硅源, 用微波辐射法在酸性条件下(pH=4.5-5.0)合成了SAPO-5分子筛, 利用X射线衍射(XRD), 傅立叶变换红外光谱(FT-IR), 扫描电镜(SEM)和Brunauer-Emmett-Teller (BET)比表面积分析对样品的结晶度、形貌和比表面等进行表征, 考察了晶化原料硅铝比对分子筛结晶度和晶体颗粒长径比(c/a)的影响, 测定了分子筛对甲苯的吸附性能. 结果显示, 采用微波辐射法合成的SAPO-5分子筛, 在硅铝摩尔比为0.50附近生成产物的结晶度最好, 晶体颗粒的长径比最小(约为1.0). 尽管不同硅铝比条件下得到的样品比表面测定结果变化不大, 但对甲苯的吸附实验显示, 在硅铝比为0.50时样品的吸附速率和饱和吸附量均达到了最大值. 这与表征所得的结晶度和长径比的变化一致, 即结晶度好,长径比小的SAPO-5分子筛具有更好的甲苯吸附性能.     

复合吸附剂SiO2·xH2O·yCaCl2的水蒸气吸附等温线

配制了一种由粗孔球形硅胶和氯化钙组成的新型复合吸附剂SiO2·xH2O·yCaCl2,测得了4个不同氯化钙含量的复合吸附剂样品(氯化钙质量分数分别为0.130,0.2733,0.384和0.510)、CaCl2和粗孔球形硅胶在25℃、35℃及45℃的水蒸气吸附等温线。实验结果表明,复合吸附剂的平衡吸水量随CaCl2质量分数增加而增加,最大可达到粗孔球形硅胶的10倍。用Dubinin-Astakhov方程回归测得的等温线,求得相应的参数。     

一种新型测试整体成型吸附剂吸附性能系统的设计、搭建及实验研究

基于吸附制冷的实际运行工况,本文设计搭建了一种新型的测试整体成型吸附剂性能装置;通过吸附床温度变化特性测试及吸附剂性能测试实验,确定了该装置用于吸附剂性能测试实验的可行性及可靠性。吸附床温度变化特性测试表明,该装置可以在有效控制整体成型吸附剂吸附脱附温度情况下,完成吸附剂在吸附和脱附循环过程中的性能测试;吸附剂性能测试实验表明,经活化后的13X沸石分子筛对吸附质-水的最大吸附量为0.196g/g,单位质量最大吸附速率为1.79×10~(-3)g/(g·min),冷凝/蒸发器的最低蒸发温度为12℃,平均冷凝温度为27℃;测试得到的13X沸石分子筛对水的吸附量与参考文献中该值的平均偏差仅为5.206%,因此,本实验装置用于整体成型以及堆积状态下的吸附剂性能测试具有可行性及可靠性;利用该系统可以为吸附制冷提供吸附剂性能的基础实验数据。     

2007年《离子交换与吸附》总目次

第1期脂肪族聚碳酸酯与聚乳酸共混型生物降解材料的热学性能、力学性能和生物降解性研究………………………………………………………………王淑芳,陶剑,郭天瑛,付涛,袁晓燕,郑俊萍,宋存江(1)等规聚丙烯接枝N-(1-萘基)马来酰亚胺的合成及其结晶形态研究…………………………………………………………………………………………………………王颖,李贺先,王国昌,杨海龙,何炳林(10)新型树脂基水合氧化铁对水体中微量砷的吸附性能研究…………………陈新庆,潘丙才,潘丙军等(16)氯化钙在10X分子筛上的微波强化分散及其氨吸附的研究……………………     

乙炔、丙烯在多种分子筛上的吸附和脱附性质

在80℃下研究了ZSM5、13X、Y、MOR、5A、SAPO34等多种分子筛和常见载体上乙炔和丙烯的吸附和脱附性能。结果表明,乙炔和丙烯在SiO2、γ-Al2O3上不吸附,而与分子筛存在较强的相互作用。对于同类型的分子筛,两者的饱和吸附量均随分子筛硅铝比的增大而减小。在同一种分子筛上,以摩尔计的丙烯吸附量均明显高于乙炔。在80℃改性β分子筛上乙炔和丙烯饱和吸附量可分别达到0.11mmol/g和4.89mmol/g,该结果明显高于文献报道的结果。     

MCM-41分子筛担载纳米TiO2复合材料光催化降解罗丹明B

采用溶胶.凝胶法将TiO2担载在介孔MCM-41分子筛上,制备了不同TiO2含量的系列TiO2/MCM-41复合材料,利用X射线衍射、N2吸附、紫外-可见光谱和透射电镜等方法对其进行表征.TiO2的晶型为锐钛矿相,复合材料的比表面积和孔体积随其中TiO2担载量(复合材料中TiO2与MCM-41的质量比)的增加而减小,TiO2的平均粒径随其担载量的增加而增大.以罗丹明B的光催化降解为探针反应,评价了TiO2/MCM-41复合材料的光催化降解活性.结果表明,在紫外光照射下,罗丹明B在该复合材料上的光催化降解反应遵循一级反应动力学,复合材料对罗丹明B的光催化降解活性明显高于商用TiO2(P-25),复合材料的光催化降解活性由复合材料的吸附能力和所含TiO2的光催化活性共同决定.     

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.     

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.     

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.     

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.     

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.