Periodic Mesoporous Organosilicas

Periodic Mesoporous Organosilicas
Author: Chang-Sik Ha
Publisher: Springer
Total Pages: 333
Release: 2018-11-07
Genre: Technology & Engineering
ISBN: 9811329591

This book provides a comprehensive overview of the fundamental properties, preparation routes and applications of a novel class of organic–inorganic nanocomposites known as periodic mesoporous organosilicas (PMOs). Mesoporous silicas are amorphous inorganic materials which have silicon and oxygen atoms in their framework with pore size ranging from 2 to 50 nm. They can be synthesized from surfactants as templates for the polycondensation of various silicon sources such as tetraalkoxysilane. In general, mesoporous silica materials possess high surface areas, tunable pore diameters, high pore volumes and well uniformly organized porosity. The stable chemical property and the variable ability for chemical modification makes them ideal for many applications such as drug carrier, sensor, separation, catalyst, and adsorbent. Among such mesoporous silicas, in 1999, three groups in Canada, Germany, and Japan independently developed a novel class of organic–inorganic nanocomposites known as periodic mesoporous organosilicas (PMOs). The organic functional groups in the frameworks of these solids allow tuning of their surface properties and modification of the bulk properties of the material. The book discusses the properties of PMOs, their preparation, different functionalities and morphology, before going on to applications in fields such as catalysis, drug delivery, sensing, optics, electronic devices, environmental applications (gas sensing and gas adsorption), biomolecule adsorption and chromatography. The book provides fundamental understanding of PMOs and their advanced applications for general materials chemists and is an excellent guide to these promising novel materials for graduate students majoring in chemical engineering, chemistry, polymer science and materials science and engineering.

Periodic Mesoporous Organosilica

Periodic Mesoporous Organosilica
Author: Steven Edward Dickson
Publisher:
Total Pages: 458
Release: 2011
Genre:
ISBN:

There is currently a great interest in the field of porous organosilica materials because of the high surface areas (> 1000 m2/g) and narrow pore size distributions which are beneficial for applications such as chromatography, chiral catalysis, sensing or selective adsorption. Periodic mesoporous organosilicas (PMOs) represent an interesting class of hybrid silica materials because of the wide variety of bridging organic groups which can be incorporated within the precursors [(OR)3Si-R-Si(OR)3] giving rise to materials with exceptional properties. We have synthesized and characterized various aromatic PMOs composed of supporting structural monomers (phenylene- or biphenylenebridged) and functional stilbene monomers (cis and trans) (1, 2). The effect of the different synthetic procedures and varying amounts of functional stilbene monomer on the properties of the materials was examined. The functional transstilbene component was determined to be well distributed in a phenylene-bridged PMO using P123 as a pore template from TEM techniques with Os staining. The trans-stilbene linkers were completely transformed to aryl aldehydes through ozonolysis with dimethylsulfide workup. Further transformation of the carbonyl functionality to an aryl imine showed a moderate level of success. Enantiomeric forms of a novel, chiral PMO precursor (CM) were synthesized and incorporated into biphenylene-bridged PMOs. Under basic pH conditions templated with C18TMACl, although very low levels of CM are incorporated, enantiomeric forms of chiral, porous materials are obtained as was verified by distinct mirror-image circular dichroism spectra. Powder XRD patterns suggest that a tightly packed asymmetric biphenylene arrangement may be necessary for the optical activity. Preliminary results using these materials as a chiral chromatographic phase are promising. Finally, a thin film morphology of an ethane-bridged PMO incorporating a thiol ligand, (3-mercaptopropyl)trimethoxysilane, was prepared on a fibre optic cable and used as a component in a heavy-metal sensing application.

Synthesis and Characterization of Ordered Cage-like Siliceous Mesostructures with Organic Pendant and Bridging Groups

Synthesis and Characterization of Ordered Cage-like Siliceous Mesostructures with Organic Pendant and Bridging Groups
Author: Rafal M. Grudzien
Publisher:
Total Pages: 238
Release: 2008
Genre: Mesoporous materials
ISBN:

Ordered cage-like mesoporous materials were synthesized and characterized in terms of their surface, structural and adsorption properties. This dissertation covers three major topics devoted to the synthesis of cage-like silicas and organosilicas. The first topic involves the improvement of synthesis conditions of cage-like silicas such as SBA-16 and FDU-1. Special emphasis was given to the study of influence of different synthesis parameters, such as variations of the TEOS/template ratio, inorganic salt, the self-assembly time, and template removal procedure. It was shown that in order to obtain FDU-1 with uniform pore entrances, large cage diameter and high pore volume, optimal triblock copolymer/silica and salt/template ratios should be within 135:1 and 2.5:1, respectively. In addition, the first synthesis step can be shortened to six hours of the original 24 without diminishing the quality of the resulting FDU-1 materials. A two-step template removal method that combines partial extraction and temperature-controlled calcination was demonstrated to be an effective way for complete removal of the template. The second topic includes the fabrication and characterization of cage-like organosilicas with pendant groups, namely, vinyl, mercaptopropyl, ureidopropyl and imidazole. These organosilicas were prepared by co-condensation of desired organosilane and tetraethyl orthosilicate (TEOS) using the optimal synthesis procedures established for pure silicas. The co-condensation synthesis afforded materials with high loadings of organic groups up to 40%, large pore diameters, and narrow pore size distributions (PSDs). Moreover, the structural transformation from cubic to hexagonal was observed under low acidic conditions, double amount of polymer, and the addition of sodium chloride. The third topic involves the incorporation of bulky isocyanurate bridging groups into periodic mesoporous organosilicas (PMOs) using tris[3-(trimethoxysilyl)propyl]isocyanurate and TEOS. The resulting PMOs possess up to 30% of bridging groups, large pore volume and high surface area. The extraction, however, was insufficient to completely remove the template. An additional heating of extracted PMOs, therefore, was carried out to remove the remaining polymer. The aforementioned materials were characterized by nitrogen and argon adsorption, powder X-ray diffraction, transmission electron microscopy, elemental analysis, high resolution thermogravimetry, and Fourier-transform infrared spectroscopy.

Micro-Mesoporous Metallosilicates

Micro-Mesoporous Metallosilicates
Author: Peng Wu
Publisher: John Wiley & Sons
Total Pages: 501
Release: 2024-05-28
Genre: Technology & Engineering
ISBN: 3527350942

Micro-Mesoporous Metallosilicates Up-to-date and in-depth text bridging the technology gap between fundamental research and industry-scale applications of porous materials for catalysis Micro-Mesoporous Metallosilicates: Synthesis, Characterization, and Catalytic Applications comprehensively introduces the chemistry and catalytic technologies of metallosilicates, an important family of microporous crystalline zeolite and heteroatom-containing mesoporous materials, with a primary focus on design synthesis, characterization, theoretical studies, and catalytic applications of titanosilicates, tin-silicates, germanosilicates and Ti-mesosilica, and more. The text covers recent advances in the synthesis of titanosilicates, including hydrothermal synthesis, dry-gel conversion, fluoride-assisted synthesis, and post-synthesis methods, along with the synthesis of metallosilicates with two-dimensional lamellar structures and their structural modifications as well as applications in selective oxidation reactions. The text also discusses synthesis of germanosilicates with specially designed organic structure-directing agents, synthesis and catalytic applications of heteroatom-containing mesoporous silica, and dendritic mesoporous silica nanoparticles with unique wrinkled center-radial structures. Overall, every important porous metallosilicate and its synthesis, characterization, pore engineering, catalytic application, and industrial technique and process are covered. Specific sample topics discussed in Micro-Mesoporous Metallosilicates include: Chemical post-modifications of titanosilicates, in terms of the effects on transfer, adsorption/desorption, and surface reactions X-Ray based techniques, ultraviolet-visible-near infrared spectroscopy, Raman spectroscopy, and solid-state NMR spectroscopy Theoretical calculation as an effective tool and supplement to understand the catalytic active center, structural character, and Brønsted/Lewis acidity Titanosilicates in the liquid-phase epoxidation reaction of propylene and propylene chloride to corresponding epoxides Effects of particle sizes, oxidation state, and location sites of Au nanoparticles, and epoxidation performance of Ti-containing materials Delivering cutting-edge research and bridging the technology gap between fundamental research and industrial applications, Micro-Mesoporous Metallosilicates is a valuable resource for chemists, materials scientists, chemical engineers, and experienced researchers in related fields.

Combined and Hybrid Adsorbents

Combined and Hybrid Adsorbents
Author: José M. Loureiro
Publisher: Springer Science & Business Media
Total Pages: 372
Release: 2006-10-03
Genre: Nature
ISBN: 1402051700

This book follows up an Advanced Research Workshop dedicated to the subject of adsorption. It presents an up-to-date review of the latest achievements in the synthesis, characterization and applications of hybrid organic-inorganic materials and of carbon and combined adsorbents. The modeling of the adsorption process, including the simulation of carbon masks used for both civil and military protection purposes is also addressed. Includes applications in environmental, military and post-disaster situations.