共查询到19条相似文献,搜索用时 93 毫秒
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《应用化工》2022,(7)
采用聚酚醛树脂球(RF)为硬模板,十六烷基三甲基溴化铵(CTAB)作为软模板,考察不同N,N-二甲基甲酰胺(DMF)含量以及晶化温度对介孔二氧化硅空心球(H-BMMs)合成的影响。采用XRD、TEM、低温N2吸附-脱附和FTIR分析产物的结构、形貌、孔道织构参数和骨架结构,并采用高效液相色谱(HPLC)法考察了H-BMMs装载布洛芬(IBU)的性能。研究表明,制备的H-BMMs具有较高的比面积(1 100 m2/g),并且壁上有孔径大小均匀的蠕虫状短孔道(2.3 nm)。随着DMF含量的增加,H-BMMs的介孔孔道逐渐减小,并且过高的晶化温度会破坏HBMMs的介孔结构。载药动力学研究发现,H-BMMs有较高的载药率(32%)。 相似文献
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N,N-二甲基甲酰胺的合成方法 总被引:1,自引:0,他引:1
N,N-二甲基甲酰胺(DMF)作为一种重要的化工原料及溶剂,被人们广泛用于染料、医药、农药、电子等行业。本文综述了DMF的合成方法,特别是2000年后合成DMF的新技术、新方法,并对各种合成DMF的催化剂以及合成路线的优缺点进行了讨论。为以后进一步研究DMF合成的方法及催化剂的选择提供理论依据。 相似文献
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N,N-二甲基甲酰胺的生产技术与市场分析 总被引:2,自引:0,他引:2
葛新泉 《化学工业与工程技术》2002,23(4):10-13
介绍了国内外N ,N -二甲基甲酰胺 (DMF)的生产技术及生产能力 ,对国内外DMF的供需情况进行了详尽分析 相似文献
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介孔材料由于具有比表面积和孔体积较大、孔径均一、纳米尺寸可调、二氧化硅无生理毒性、热稳定性较好等一系列特点而引起了人们广泛的兴趣和关注.控制介孔二氧化硅的形貌和尺寸可以拓展介孔二氧化硅的应用,尤其是开发介孔二氧化硅在生物医学、 相似文献
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A cationic surfactant assisted selective etching strategy to hollow mesoporous silica spheres 总被引:1,自引:0,他引:1
Hollow mesoporous silica spheres have recently attracted increasing attention. However, effective synthesis of uniform hollow mesoporous spheres with controllable well-defined pore structures for fundamental research and practical applications has remained a significant challenge. In this work, a straightforward and effective "cationic surfactant assisted selective etching" synthetic strategy was developed for the preparation of high-quality hollow mesoporous silica spheres with either wormhole-like or oriented mesoporous shell. The as-prepared hollow mesoporous silica spheres have large surface area, high pore volume, and controllable structure parameters. Our experiments demonstrated that cationic surfactant plays critical roles in forming the hollow mesoporous structure. A formation mechanism involving the etching of solid SiO(2) accelerated by cationic surfactant followed by the redeposition of dissolved silica species directed by cationic surfactant is proposed. Furthermore, the strategy can be extended as a general strategy to transform silica-coated composite materials into yolk-shell structures with either wormhole-like or oriented mesoporous shell. 相似文献
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以1,12-二溴十二烷、S-烟碱和钨酸钠为原料制备手性钨酸离子液体,硅酸钠为硅源,经一步水热法制得功能化的空心介孔硅球。用SEM、TEM、FTIR、UV-Vis、N2吸附-脱附、XPS、ICP-OES、水接触角和圆二色谱(ECD)等对其结构进行表征,并考察其对于苯乙烯双羟化反应的催化性能。结果表明,空心介孔硅球的直径约为100 nm,比表面积为20 ~ 53 m2/g,平均孔径为7.7 ~ 16 nm;手性钨酸离子液体成功嵌入到介孔空心硅球,固体具有圆二色性,可用于苯乙烯双羟化反应,使n(W)∶n(Si)=0.25∶0.75时制得的催化剂催化性能最好、(R)-苯基乙二醇产率达89.6%,循环使用5次后产率仍可达87%;比较未含钨酸离子液体的样品为无定形纳米颗粒,因此推测钨酸基手性离子液体对介孔空心硅球形成具有导向作用。 相似文献
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Wen-Long Huo Xiaoyan Zhang Zunlan Hu Yugu Chen Yali Wang Jinlong Yang 《Journal of the American Ceramic Society》2019,102(3):955-961
Ceramic foams with multi-scale pores and large specific surface area have received extensive attention due to their unique structure and superior properties. Considering that there are still challenges to synthesize porous ceramics with large specific surface area, a novel ceramic foam material with ultra-large specific surface area has been prepared using hollow silica mesoporous spheres (HMSSs) as building block in this work. These building blocks were made weakly hydrophobic in order to produce HMSS particle stabilized foams. The foams exhibit a uniform primary macropore structure, which is composed of a three dimensional HMSS-assembled network, via HMSS-stabilized foams. The influence of sintering temperature on the microstructure and properties of HMSS foams is investigated. The HMSS foams exhibit highest specific surface area of 1733 m2/g, attributed to the radial mesopores in HMSS shell, when sintered at between 500°C and 800°C. This specific surface area is much higher than that of existing ceramic materials. The uniform pore structure and ultra-large specific surface area make it a promising lightweight material in potential application fields, including catalyst, adsorption, fire-resistant thermal insulation, and load and control release system. 相似文献
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在乙醇/水的混合溶液中,采用聚乙烯吡咯烷酮(PVP)为分散剂,偶氮二异丁腈(AIBN)为引发剂,通过分散聚合法制备出聚苯乙烯(PS)微球。然后以微球为模板,PS粒子作为核,SiO_2作为壳,在600℃时经过热分解得到SiO_2空心球。通过热分析仪、扫描电子显微镜对制得的空心球进行了表征和分析,并讨论其影响因素。 相似文献
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介孔中空材料有特定孔道结构,具有中空、密度小、比表面积大的特点,因而具有较好的渗透性、吸附性、筛分分子能力和光学性能,成为具有广泛应用前景的热点研究材料。详细地介绍了国内外新型功能材料介孔中空二氧化硅及硅基微球主要制备方法,包括表面沉积法、层层组装法、原子转移自由基聚合法、喷雾法、微乳液法。同时介绍了合成的介孔、中空二氧化硅和硅基微球的形貌特点及应用。指出不同方法、不同制备条件对材料的形貌、孔径大小、孔形状及材料晶形有很大影响,条件温和、步骤简单、环境友好的制备方法是发展趋势。 相似文献
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The synthesis of mesoporous MCM-41 silica materials was investigated at various conditions. A series of ordered mesopores MCM-41 silica materials was synthesized in concentrated reaction mixtures. The influence of water concentration at the constant ratio of the remaining reagents on the morphology and structural parameters of MCM-41 was studied. Hexadecyltrimethylammonium bromide CTAB was used as a structure-directing agent. The pore size, the wall thickness and cylindrical pores array were characterized by powder X-ray diffraction and nitrogen adsorption. The presented results show that in concentrated reaction mixtures, the pore size and the thickness of the pore walls remain practically constant. However, the dimensions of silica particles depend strongly on the water concentration. A high regularity of pore structure for large MCM-41 particles synthesized in concentrated solution was supported by independent AFM technique. 相似文献
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Chun Liu Chen Ge Aili Wang Hengbo Yin Min Ren Yunsheng Zhang Longbao Yu Tingshun Jiang 《Korean Journal of Chemical Engineering》2011,28(6):1458-1463
Uniform sized and integrated hollow silica spheres with porous shells were prepared by using sulfuric and carboxylic acid-functionalized
polystyrene latex spheres as templates, sodium silicate as a precursor, and cetyltrimethylammonium bromide as a shell structure-directing
agent. When polystyrene-methyl acrylic acid latex spheres were used as the templates, the pores in the shells of the resultant
hollow silica spheres were composed of both micropores and mesopores. The pores in the shells of the hollow silica spheres
were mainly composed of mesopores when sulfonated polystyrene-methyl acrylic acid latex spheres were used as the templates.
The shell thickness and the specific surface area of the hollow silica spheres increased with the increase in the surface
acidity of the latex spheres. 相似文献
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E. Yu. Trofimova D. A. Kurdyukov Yu. A. Kukushkina M. A. Yagovkina V. G. Golubev 《Glass Physics and Chemistry》2011,37(4):378-384
A technique has been developed for synthesis of submicron monodispersed mesoporous spheres of amorphous silica from an alcohol-water-ammonia mixture by means of tetraethoxysilane hydrolysis in the presence of hexadecyltrimethylammonium bromide. The mechanism of sphere formation from aggregates of close-packed surfactant cylindrical micelles coated by silica has been proposed. The specific surface area in the synthesized spheres is higher than 800 m2/g, whereas the pore volume and average diameter are equal to 0.63 cm3/g and 3 nm, respectively. The average size of particles is shown to decrease twice after the temperature of the synthesis is increased twice. According to the data of atomic force spectroscopy and dynamic light scattering, the average diameter of mesoporous spheres can be controllably varied in the range 300–1500 nm with a root-mean-square deviation of no more than 6%. 相似文献
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Tomiko M. Suzuki Tadashi Nakamura Eiichi Sudo Yusuke Akimoto Kazuhisa Yano 《Microporous and mesoporous materials》2008,111(1-3):350-358
A new type of sulfonic acid-functionalized monodispersed mesoporous silica spheres (MMSS) were synthesized directly by co-condensation and subsequent oxidation. By changing the methanol ratio, sulfonic acid-functionalized MMSS with different particle diameters (390–830 nm) and the same mesopore sizes were successfully synthesized. TEM observations revealed that the mesopores were aligned radially from the center towards the outside of the spheres, even in the sulfonic acid-functionalized MMSS. The catalytic activities of the sulfonic acid-functionalized MMSS were studied in condensation reactions between 2-methylfuran and acetone, and it was found that their catalytic activities are highly dependent on the particle diameters. In addition, the catalytic activity of MMSS was much higher than that of other forms of mesoporous silica due to its radially-aligned mesopores. 相似文献