Synthesis of Compact NaA Zeolite Membrane by Microwave Heating Method

A continuous and dense NaA zeolite membrane was synthesized by microwave heating method while employing a multi-step seeding LTA zeolite with the average size of 120 rim. The gas H2/N2 mixture separating results indicated that the mixture selectivity increased with increasing of synthesis times. In addition, selectivity of the three-step synthesis was higher than the value(3.74) expected from Kundsen diffusion.     

同晶置换改性FAU分子筛结构及吸附性能的密度泛函理论研究

采用密度泛函理论(DFT)方法,考察了八面沸石(FAU)型分子筛β笼孔道结构内含氧化合物(甲醇、二甲醚、丙醛)的吸附,并进一步计算研究了Zn,Ca同晶置换改性的作用机理.研究结果表明,β笼孔道结构内,Al原子为甲醇、二甲醚和丙醛的吸附活性位,Si原子无吸附活性.Zn,Ca掺杂的β笼结构内,正2价的Zn和Ca掺杂替换正3价的Al,导致邻近的Si原子位置形成缺电子空穴,增强了甲醇、二甲醚和丙醛的吸附,而杂原子Zn和Ca本身并没有吸附活性.     

微波辐射法合成NaX分子筛

NaX是低硅铝比的八面沸石,一般在低温水热条件下合成.因反应混合物配比不同,以及采用的反应温度不同,晶化时间为数小时至数十小时不等. 近年来,微波辐射方法被应用于无机及有机化合物的合成中.Chu Pochen等在专利文献中报道了微波辐射法在沸石分子筛合成中的应用,其中提到了NaX分子筛,但对合成     

钛硅ZSM-5沸石分子筛的微波辐射法合成与表征

以工业硅溶胶为硅源,廉价的乙醇作模板剂,用微波辐射的方法 成功地合成了高结晶度的钛硅 Ｚ Ｓ Ｍ ５ 分子 筛。确定合 成条 件为：ｍ ｏｌ Ｅｔ Ｏ Ｈ ∶ ｍ ｏｌ Ｓｉ ＝ ０． １～ ０．４,微 波反 应釜 压力 为 １ Ｍ Ｐａ, 晶化时 间２００ｍ ｉｎ。利用 Ｘ Ｒ Ｄ, Ｓ Ｅ Ｍ , Ｉ Ｒ 等方法 对钛硅 Ｚ Ｓ Ｍ ５ 分子 筛的物相和晶貌作 了表征,结果表明 钛已进入分子筛骨架。微波辐射法合成大大地缩短了反应时间,简化了操作,合成的样品粒度 小且均匀。     

Forming and Gathering of SnO2 Nanoparticles on External Surface of High Silica TON, MFI and FAU Type Zeolites

Tin dioxide （SnO2） nano-particles were prepared on high silica TON, MFI and FAU type zeolites by impregnation of SnC12 solution and subsequent calcination at 873 K. XRD and SAED were used to characterize the crystalline phase, and TEM was used to characterize the morphology, the particle size and the agglomerative state of the formed nano-materials. The nano-particles, which possess 8 nm, 10-80 nm and 6 nm in size, were found to form on the outer surface of TON, MFI and FAU zeolites, respectively. SnO2 microcapsules and SnOz netlike nanostructure were obtained by decomposition of SnO2-TON and SnO2-MFI in 40% hydrofluoric acid at room temperature. Compared with the nano-particles formed on NaY zeolite, the special morphology and the agglomerative state of SnO2 nanostructures on TON and MFI type zeolites with one and two dimension channel system indicate that the heterogeneous framework, surface structure and property perform important function for forming and growing SnO2 nanostructure on the outer surface of the zeolites.     

小分子无机气体在NaA分子筛膜上的渗透分离性能

采用多次合成的方法,在微波加热15min下合成出较为致密的A型分子筛膜。经过四次合成的分子筛膜上H2/N2和H2/CO的理想分离系数分别为4．33和4．64,高于努森扩散值(分别为3．74和3．74),表明膜是连续致密的。     

Preparation of CaS:Eu2+ Phosphor by Microwave Heating Method and its Luminescence

Alkaline-earth sulfides have been found to be excellent host materials for the cathodo-,photo-, thermo-, and electfo-luminescent phosphorsl-3. Red-emitting CaS:Eu2+ havealready been described in the literatUre4,5. In the past, calcium sulphide was mainlyprepared by conventional high temperatUre solid state method through the stream of H,Sand HZ or CS, as sulphurizing and protection atmosphere, which expended quite longreaction time of 2-72 h6 and consumed a great deal of the sources of ene…     

微波加热对以槲皮素为甙元的黄酮甙的稳定性的影响

以乙醇为溶剂．分别采取微波和回流加热萃取法从番石榴叶中萃取槲皮素．高效液相色谱法测定槲皮素的萃取收率。对回流萃取液进行微波加热．槲皮素收率随微波加热温度的增加而显著增加。分别测定了温度为100、110、120℃的微波萃取动力学曲线以及60、70和78℃的回流加热萃取动力学曲线,计算结果显示,微波萃取和回流加热萃取均符合一级动力学方程,微波萃取槲皮素的活化能是回流加热萃取活化能的2倍多．平均表观速率常数是回流加热萃取的125倍。计算得到的活化能数据和实验结果均显示微波加热产生的高温可导致以槲皮素为甙元的黄酮甙发生分解。     

微波场对SrTiO3化学合成中热过程的影响

在分析微波场中 SrTiO3化学合成体系与电磁场相互作用的基础上 ,探讨合成体系在微波场中的加热机制和影响升温的主要因素（如合成体系的介电性质、保温材料的结构、生坯的致密度等） .结果表明 ,TiO2和 SrCO3在低温阶段对体系的升温速率的贡献相接近 ;高温阶段体系升温主要是 TiO2的贡献 ,同时产物对升温有较大的影响 .微波合成与常规合成在加热方式上的明显不同,对合成过程、合成时间等影响较大 .     

Microwave Synthesis of a&b-Oriented Zeolite T Membranes and Their Application in Pervaporation-Assisted Esterification

High-performance a&b-oriented zeolite T membranes were prepared by the microwave-assisted hydrothermal method. The membranes were applied to the pervaporation-assisted esterification of acetic acid and n-butyl alcohol at 383 K. Zeolite T membranes could effectively remove water product from the reactant mixtures and improve the conversion of acetic acid to 100% without the loss of reactants or products     

Microwave assisted synthesis of spiro-2,5-diketopiperazines

A general and efficient method for the synthesis of spiro-2,5-diketopiperazines (spiro-DKPs) is described. Cyclization of Boc-protected dipeptides containing spiro-amino acids by microwave assisted heating in water furnished the corresponding spiro-DKPs. The spiro-amino acids were prepared by combining stereoselective alkylation reactions using the Schöllkopf methodology for amino acid construction with Grubbs ring-closing metathesis (RCM) methodology using ruthenium complexes. The RCM reactions and all subsequent transformations to the spiro-DKPs were run with microwave assisted heating, resulting in high yields and short reaction times for all steps.     

甲基丙烯酸丁酯微波无皂乳液聚合

以过硫酸钾作为引发剂进行了甲基丙烯酸丁酯的微波无皂化乳液聚合,讨论了单体浓度和引发剂用量对单体转化率,粒子粒径及其分布的影响,并与常规乳液聚合进行了比较。结果表明,通过微波无皂乳液聚合,乳胶粒子的粒径分布没有明显变化,但是聚合速率大为增加。     

Template-Free Synthesis of AlPO 4 -H1 by Microwave Heating

Microwave heating enhanced the crystallization of aluminophosphate gels, and AlPO 4 -H1 was successfully obtained without using organic template reagents in a short reaction time. The use of amorphous aluminum hydroxide as an aluminum source and the addition of hydrochloric acid were found to be essentially important to obtain AlPO 4 -H1 as a single phase. Nitrogen and water adsorption properties were studied by measuring the adsorption isotherms.     

原位合成分子筛多孔层毛细管柱的制备与性能考察

在毛细管内壁,原位合成了Ｎａ－Ａ型分子筛,成功制备出一类新型分子筛多孔尾毛细管柱。和涂渍相比,原位合成法在毛细管内壁形成的分子筛层更加均匀、致密度、更能体现出分子筛对低碳烃的分离特性,实验表明用超短毛细管柱即可对低碳烃进行良好的分离。     

Synthesis of Substituted Salicylanilides under Microwave Irradiation

Summary. Salicylanilides were prepared in 70–95% yields in 4–8min from phenyl salicylate or phenyl 4-methoxysalicylate and substituted anilines under microwave irradiation under solvent free conditions.Received October 17, 2002; accepted October 22, 2002 Published online July 3, 2003     

Zeolite HY and Silica Gel as New and Efficient Heterogenous Catalysts for the Synthesis of Triarylimidazoles under Microwave Irradiation

Summary.  Zeolite HY and silica gel efficiently catalyzed the three component condensation of benzil, benzaldehyde derivatives, and ammonium acetate under solvent-free conditions and microwave irradiation. Received February 22, 2000. Accepted (revised) March 22, 2000     

Microwave dielectric spectra and molecular relaxation in formamide-N,N-dimethylformamide binary mixtures

The dielectric dispersion and absorption spectra of formamide (FA), N,N-dimethylformamide (DMF) and their binary mixtures are investigated in the frequency range of 500 MHz to 20 GHz at 30 °C in view of the organic synthesis by microwaves heating using amides solvents. The concentration dependent values of molecular reorientation relaxation times lower than that of the ideal mixing behaviour have been attributed to the cooperative dynamics of H-bonded FA–DMF structures. The molar ratio of stable adduct is 2:1 of FA to the DMF, which is determined from the concentration dependent excess static dielectric constant and the relaxation time plots of these binary mixtures. Electrode polarization effect and ionic conduction in FA and DMF were investigated from their dielectric dispersion spectra in the low frequency region of 20 Hz to 1 MHz.     

微波辐射下巴比妥的N—烃基化反应

在微波辐射下，以无水碳酸钾作为碱性试剂和载体，巴比妥或巴比妥钠和卤代烃在固相能迅速地发生反应生成相应的Ｎ－烃基化产物。