69465-84-5Relevant articles and documents
Preparation and separation properties of oxalylurea-bridged silica membranes
Mizumo, Tomonobu,Muragishi, Haruna,Yamamoto, Kazuki,Ohshita, Joji,Kanezashi, Masakoto,Tsuru, Toshinori
, p. 433 - 438 (2015)
Two new bridged alkoxysilanes, bis(triethoxysilylalkyl)-N,N′-oxalylureas (alkyl = methyl or n-propyl), bearing a highly rigid and polar oxalylurea unit in the bridges, were employed as precursors of bridged silica membranes. The gas and water separation performance of the membranes prepared from the precursors using the sol-gel process was investigated. Interestingly, the membrane properties depended on the alkyl chain length. The membrane containing methylene units (alkyl = methyl) was porous and rather hydrophilic but the other with longer propylene units (alkyl = n-propyl) was non-porous and more hydrophobic. High H2/SF6 gas permeance ratios of 3100 and 1700, and NaCl rejections of 89 and 85% for 2000 ppm aqueous NaCl were obtained using the membranes containing methyl and n-propyl, respectively. The membrane with alkyl = methyl also showed a high CO2/N2 permeance ratio of 20.6 at 50°C. These results indicate the potential applications of the membranes as gas and water separation materials.
Robust urethane-bridged silica aerogels available for water-carved aerosculptures
Zhang, Yulu,Wang, Jin,Wei, Yong,Zhang, Xuetong
, p. 1953 - 1958 (2017)
Molecular bridged silica aerogels have received extensive interest in recent years due to their easily controlled mechanical properties varying with different organosilane precursors, and without any further post-modification. In this work, a series of novel and robust molecular bridged silica aerogels were prepared by using a symmetrical urethane-bridged monomer, named N,N-bis(propyltriethoxysilyl)carbamide (bPTSCA), which was synthesized via a solvent-free exothermic reaction between 3-isocyanatopropyltriethoxysilane (IPTES) and 3-aminopropyltriethoxysilane (APTES) for several minutes at normal temperature and pressure. The influence of catalysts on the obtained gels and aerogels was studied in detail. It was found that NH4F aqueous solution showed the most effective catalysis capability, and the corresponding aerogels were intact with slight shrinkages. The mechanical strength of these aerogels could reach as high as 100 times more than that of the native silica aerogels (unbridged), and the strength could be easily adjusted from a rigid region to an elastic region simply by varying the sample density. Moreover, these aerogels possessed an interesting character of regional shrinking when encountering with water, which made it possible to fabricate artistic aerosculptures with water or other polar solvents as a graver.
New silatranes possessing urea functionality: Synthesis, characterization and their structural aspects
Puri, Jugal Kishore,Singh, Raghubir,Chahal, Varinder Kaur,Sharma, Raj Pal,Wagler, J?rg,Kroke, Edwin
experimental part, p. 1341 - 1348 (2011/05/09)
The present work aims at the synthesis of various novel silatranes bearing substituted urea functionality. Nucleophilic addition of various amines (morpholine, aniline, ethylenediamine and 3-aminopropyltriethoxysilane) to 3-isocyanatopropyltriethoxysilane