The highly effective catalytic synthesis of 1 4-butynediol (BD) from the Reppe process is a fascinating technology in modern chemical industry In this work we reported the effects of the existential states of Mg species in the CuO/silica-magnesia catalysts for the ethynylation of formaldehyde in a simulative slurry reactor The physichemical properties of the supports and the corresponding Ambient pressure drying Methanol steam reforming CO selectivity abstract In this work the copperesilica aerogel catalyst was prepared by cogelation of copper and silica precursors in a solegel process followed by chemical surface modification and ambient pressure drying The results of characterizations by XRD BET FE-SEM TEM FTIR and TPR showed the prepared catalysts had high surface

Studying on the preparation and application of silica

The structure feature and ther mal insulation property of silica aerogel are introduced in this paper then the preparation methods and application perspective of Silica aerogel composites for thermal insulation are summarized and commented properly and the research dire

The preparation of TEM samples can obscure particle sizes through drying and TEM images do not indicate whether particles are solvated [121 Because of these inadequacies there is still uncertainty about the about the size and the structure of the initial nuclei that should be incorporated in the monomer addition and controlled aggregation models For example Matsouskas and Gulari [6] in the

01/08/2011This paper examines the effect of the amount of Cu(II) cations and modifiers on the physical properties of Cu:SiO 2 aerogels The Cu:SiO 2 aerogel films were also synthesized by a copolymerization sol-gel reaction followed by ambient drying Among the three surface modifiers (TMCS MTMS and HMDSZ) that were examined the HMDSZ was found to be effective regarding stability and

08/03/2011A copper-doped silica composite aerogel with high specific surface area was prepared using a sol-gel method at ambient pressure A drying control chemical additive (DCCA) N N-dimethylformamide (DMF) was introduced to the composite sol of tetraethyl orthosilicate (TEOS) and copper nitrate (Cu(NO3)23H2O) during the synthesizing process The influence of the preparation

The research proved that by increasing the fiber amount the density of the composite lowered from 0 140 for pure aerogel to 0 078 g/cm 3 for the aerogel with 80% fiber content whereas the thermal conductivity of the composite increased from 0 013 to 0 025 W/(m K) A side effect of adding this amount of hydrophilic fibers was the decrease of the contact angle of the formed composites

Preparation and characterization of Cu:SiO2 aerogel films

01/08/2011This paper examines the effect of the amount of Cu(II) cations and modifiers on the physical properties of Cu:SiO 2 aerogels The Cu:SiO 2 aerogel films were also synthesized by a copolymerization sol-gel reaction followed by ambient drying Among the three surface modifiers (TMCS MTMS and HMDSZ) that were examined the HMDSZ was found to be effective regarding stability and

Preparation of Cu-SiO 2 composite aerogel by ambient drying and the influence of synthesizing conditions on the structure of the aerogel[J] Chinese Science Bulletin 2011/07 7 Fluorescence Enhancement of Modified Silver Nanoparticles[J] Journal of Nanoscience and Nanotechnology 2011/11 8 Ag APS TiO 2 [J]

On the basis of the variations of preparation conditions the densities of aerogels are in the range of 200~400 kg•m-3 and the specific surface areas can vary from 250 m2•g-1 to 300 m2•g-1 while their average pore sizes are 11~20 nm with porosity of about 91% Key words: Aerogel Nonsupercritical drying SiO 2 Silica

A copper-doped silica composite aerogel with high specific surface area was prepared using a sol-gel method at ambient pressure A drying control chemical additive (DCCA) N N-dimethylformamide (DMF) was introduced to the composite sol of tetraethyl orthosilicate (TEOS) and copper nitrate (Cu(NO3)23H2O) during the synthesizing process The influence of the preparation conditions

The preparation of TEM samples can obscure particle sizes through drying and TEM images do not indicate whether particles are solvated [121 Because of these inadequacies there is still uncertainty about the about the size and the structure of the initial nuclei that should be incorporated in the monomer addition and controlled aggregation models For example Matsouskas and Gulari [6] in the

Thus Bianchi et al (139) measured by volumetric adsorption a concentration of 10" sites cm-' for alumina aerogel at temperatures ranging between 300C and ambient Kramer and Andre (It?) using T P D of hydrogen on Pt/Al O samples reported values of - 2 x 1 O I 2 sites cm-2 at 400C and 710 Torr H The same site density ( 10" sites cm-') was also found this time on silica by

article {32259 title = {An assessment of the load modifying potential of model predictive controlled dynamic facades within the California context} journal = {Energy and Buildings} volume = {210} year = {2020} month = {01/2020} pages = {109762} abstract =

Cu-SiO_2 2) Ni nanowires/silica aerogel composite Nanoporous SiO_2 aerogel based thermal insulation composite could be widely used in thermal protection systems of space aircrafts military thermal battery heat energy chemical metallurgy and fire protection for its low thermal conductivity high mechanical property low bulk density and easy-to-handle SiO_2

Synthesis of strong silica aerogel by PEDS at ambient

In this study a strong silica aerogel was synthesized by using polyethoxydisiloxne (PEDS) as a precursor and hexamethyldisilazane (HMDZ) as a surface modifier The obtained aerogel was characterized by scanning electron microscopy (SEM) Fourier transform infrared spectroscopy (FT-IR) and nitrogen adsorption/desorption at 77 K The aerogel product holds a surface area of 883 m2/g total pore

16/02/2017Moreover the aging process is important in terms of obtaining a homogenous and transparent silica aerogel in the next synthesis stage supercritical drying most frequently in low-temperature processes in CO 2 or by drying in ambient pressure Drying in lowered temperature and in lowered pressure is accompanied by high capillary forces causing contraction and fracture of the gel

Inconel 718 was spin coated twice and fourfold with a sol to obtain 200- and 400-nm-thick transition alumina films on the surface Bare and sol–gel alumina-coated Inconel 718 samples were exposed to NaCl solution to study their corrosion behavior by means of electrochemical impedance spectroscopy

Abstract: The preparation of monolithic silica aerogels via non-supercritical drying is realized by the following procedures:(1) formation of silica alcogels with perfect network structure by controlling two-step hydrolysis and condensation reaction rates of tetraethoxysilane; (2) improvement and reinforcement of network structure and strength of silica gels through exchanging the pore fluid

Cu-SiO_2 2) Ni nanowires/silica aerogel composite Nanoporous SiO_2 aerogel based thermal insulation composite could be widely used in thermal protection systems of space aircrafts military thermal battery heat energy chemical metallurgy and fire protection for its low thermal conductivity high mechanical property low bulk density and easy-to-handle SiO_2

Detailed catalyst preparation method and characterization were described elsewhere [21] Copper-silica aerogel was synthesized by cogelation of copper and silica precursors followed by solvent exchange and chemical surface modification and dried at ambient pressure Then dried copper-silica aerogels were placed in a furnace and calcined in air

Preparation of Cu-SiO 2 composite aerogel by ambient drying and the influence of synthesizing conditions on the structure of the aerogel LI GuiAn* ZHU TingLiang DENG ZhongXun ZHANG YaJuan JIAO Fei ZHENG HaiRong College of Physics and Information Technology Shaanxi Normal University Xi'an 710062 China Received September 5 2009 accepted December 10 2009 A copper-doped silica