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1.
介孔分子筛MSU-1的合成 总被引:1,自引:0,他引:1
MSU X介孔分子筛具有三维立体交叉排列的蠕虫状孔道结构,有利于客体分子在其孔道内扩散[1]。目前合成MSU X的原料[2 4]TEOS水解速度慢,合成过程较易控制,但价高、易燃、有刺激性。本文采用文献[5 7]法,以水玻璃、A(EO)9为原料,在酸性至近中性的范围里合成了MSU 1介孔分子筛,与TEOS为原料的MSU 1合成进行了比较,考察了pH值和不同类型表面活性剂(脂肪醇聚氧乙烯醚和烷基酚聚氧乙烯醚)对产物结构性质的影响。1 实验部分1 1 试剂和仪器水玻璃(SiO2%≈26、Na2O%≈8),工业级,青岛海洋化工厂生产;脂肪醇聚氧乙烯醚非离子表面活性… 相似文献
2.
Isao Hasegawa 《Journal of Sol-Gel Science and Technology》1994,2(1-3):127-130
29Si NMR peaks due to species with the double four-membered ring siloxane backbone composed of both Si(O–)4/2 and CH3Si(O–)3/2 units, (CH3)
n
Si8O
20 – n
/(8 – n) –
(n=1–3), formed by co-hydrolysis of tetraethoxysilane and methyltriethoxysilane in the presence of tetramethylammonium ions in methanol have been assigned. It has been found that 29Si NMR peaks due to Si(OSi)3(O–) units shift to lower frequencies by replacement of the adjacent Si(O–)4/2 units by CH3Si(O–)3/2 units, in other words, with increasing m value in Si[OSi(O–)3]3 – m
[OSi(CH3) (O–)2]
m
(O–) (m=0–2). Peaks from CH3
Si(OSi)3 units in the species have also appeared as separated due to the kind of neighbor structural units. On the basis of the assignments, positions of CH3Si(O–)3/2 units in the cubic octameric siloxane framework of (CH3)
n
Si8O
20 – n
/(8 – n) –
(n=2, 3), for both of which three isomers are present, have been estimated. 相似文献
3.
Julien Huser Sophie Bistac Christelle Delaite Didier Dentel Mickaël Derivaz Mohamed Zanouni 《Surface and interface analysis : SIA》2015,47(4):523-528
The grafting of trialkoxysilane molecules should also give rise to the formation of a siloxane network at the substrate's surface when trialkoxysilanes are used. Other candidates that might be able to act as adhesion promoters at metallic surfaces are dimethylalkoxysilanes. The advantage of dimethylalkoxysilanes is that only one silanol group is produced during the hydrolysis step, leading to the formation of a grafted monolayer onto the steel. Moreover, the chemical grafting of stainless steel, which exhibits a low surface reactivity, is of great interest for industrial applications such as adhesive bonding or coatings. The objective of this work was to chemically graft dimethylalkoxysilanes onto AISI 316L stainless steel and to analyze the grafted layer by X‐ray photoelectron spectroscopy (XPS). Investigation of the hydrolysis of these molecules in aqueous solutions was also performed by proton nuclear magnetic resonance spectroscopy (1H NMR). The grafting of 3‐(ethoxydimethylsilyl)propylamine (APDES) and 3‐glycidoxypropyldimethylethoxysilane (GPDES) was achieved onto stainless steel after a controlled hydrolysis reaction. A pH inferior or equal to 5 was necessary to obtain a sufficient hydrolysis of silanes. XPS results have evidenced the grafting of the silanes onto stainless steel. The signal of the Si 2p peak clearly showed the formation of a covalent bond between APDES and the stainless steel surface through the O atoms giving rise to a uniform layer of adsorbed molecules. Moreover, this grafted layer is strongly stable as no removal of the alkoxysilane was observed after immersion in hot water which is very critical for these molecules. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
Selective Formation of Alkoxychlorosilanes and Organotrialkoxysilane with Four Different Substituents by Intermolecular Exchange Reaction
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Yasuhiro Tamura Prof. Hiroaki Wada Prof. Atsushi Shimojima Prof. Kazuyuki Kuroda 《化学:亚洲杂志》2016,11(22):3225-3233
Alkoxychlorosilanes are scientifically and industrially important toward preparing silicone and silica as well as preparation of siloxane‐based nanomaterials by stepwise reactions of Si?OR (R=alkyl) and Si?Cl groups. Intermolecular exchange of alkoxy and chloro groups between alkoxysilanes and chlorosilanes (functional group exchange reaction) provides an efficient and environmentally benign route to alkoxychlorosilanes. BiCl3 as a Lewis acid catalyst can promote the functional group exchange reactions more efficiently than conventional acid catalysts. Higher reactivity has been observed for chlorosilanes with smaller numbers of Si?CH3 groups and for alkoxysilanes with larger numbers of Si?CH3 groups. The reaction mechanism is proposed and selective syntheses of alkoxychlorosilanes are demonstrated. These findings also enable us to synthesize an organotrialkoxysilane with four different substituents. 相似文献
5.
Amanda S. Fawcett John B. Grande Michael A. Brook 《Journal of polymer science. Part A, Polymer chemistry》2013,51(3):644-652
Silicone room temperature vulcanization elastomers are usually formed through either a platinum‐catalyzed hydrosilylation or tin‐catalyzed moisture cure. In this article, we show that it is possible to create robust, transparent silicone elastomers without the need for metal catalysts. Hydrogen‐terminated silicone polymers are crosslinked by tri‐ or tetraalkoxysilane crosslinkers in a condensation process catalyzed by the presence of trispentafluorophenylborane catalyst to give elastomers and alkane by‐products. This procedure allows for very fast cure times (< 30 s to a tack free state): the process is more conveniently controlled with the addition of a small amount of solvent. Physical and mechanical properties are readily modified by control of the chain length of the starting polymer, the functionality and nature of the alkoxy group on the crosslinker. Organofunctional groups, useful for further polymer modification, can optionally be incorporated by judicious choice of readily available starting materials. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
6.
Isao Hasegawa 《Journal of Sol-Gel Science and Technology》1993,1(1):57-63
Tetracethoxysilane (TEOS) and methyltriethoxysilane (MTEOS) have been co-hydrolyzed in methanolic solutions containing tetramethylammonium ions that only affect polymerization of silicate species (hydrolysis products of TEOS) to form the Si8O
20
8–
cubic octameric silicate species. The effects of water content and TEOS-to-MTEOS molar ratio on the distribution of species formed in the solutions have been investigated with the trimethylsilylation technique and 29Si n.m.r. spectroscopy. Formation of Si8O
20
8–
and the cubic octameric species consisting of both Si(O–)4 and CH3Si(O–)3 units, (CH3)nSi8O
20–n
(8–n)–
(n=1–5), is found in the solutions. The increase of water content in the solutions solely results in increasing yield of Si8O
20
8–
in spite of the presence of hydrolysis products of MTEOS together with those of TEOS, suggesting that water in the solutions plays an important role in the formation of Si8O
20
8–
with the aid of tetramethylammonium ions. The TEOS-to-MTEOS molar ratio varies the distribution that is kept under control by the water content, increasing yields of (CH3)nSi8O
20–n
(8–n)–
(n=1, 2). It is found that the water content and TEOS-to-MTEOS molar ratio determine the reaction conditions effective for the formation of CH3Si(O–)3 unit-containing cubic octameric species. 相似文献
7.
Phosphonate‐functionalized polysiloxanes have been prepared with a new siloxane/phosphonate monomer. The reaction of 3‐chloropropylmethyldimethoxysilane with trimethylphosphite or triethylphosphite produces several new monomers containing pendant phosphonate groups. Copolymerization with dimethyldimethoxysilane has produced polymers soluble in most organic solvents. The acid hydrolysis of the phosphoryl esters has produced hydrophilic siloxane polymers containing phosphonic acid groups. The thermal properties of the polymers and several related small molecules have been compared with thermogravimetric analysis. Both the monomers and the resulting polymers have been characterized with 1H, 13C, 31P, and 29Si NMR. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 48–59, 2003 相似文献
8.
9.
M. G. Voronkov N. F. Chernov O. M. Trofimova T. N. Aksamentova 《Russian Chemical Bulletin》1993,42(11):1883-1886
The interactions of sodium salts of 2-mercaptobenzoxazole, 2-mercaptobenzothiazole and 2-mercaptobenzimidazole with (chloromethyl)trimethyl-, chloromethyl(dimethoxy)methylor (chloromethyl)trimethoxysilanes have been shown to result in the corresponding previously unknown (2-heterylthiomethyl)triorganylsilanes. Transetherification of (2-heteryl-thiomethyl)trimethoxysilanes with triethanolamine gives 1-(2-benzoxazolylthiomethyl)-, 1-(2-benzothiazolylthiomethyl)- and 1-(2-benzimidazolylthiomethyl)silatranes. The reaction of the corresponding alkoxysilanes with boron trifluoride etherate leads to (2-benzoxazolylthiomethyl)- and (2-benzothiazolylthiomethyl)-substituted trifluorosilanes and methyldifluorosilanes having a dragonoid chelate structure. By the hydrolysis of (2-heterylthiomethyl)trimethoxysilanes, new organosilicon sorbents, poly(2-heteryl-thiomethyl)silsesquioxanes have been synthesized.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1965–1969, November, 1993. 相似文献
10.
Torbj⊘rn Vrålstad Gisle Øye Johan Sjöblom Michael Stöcker 《Journal of Dispersion Science and Technology》2013,34(4):489-496
MCM‐41, MCM‐48, and SBA‐15 have been functionalized with cobalt by grafting of different organosilane molecules and then calcined to remove the organic moieties. The materials have been characterized by N2‐sorption, UV‐vis spectroscopy, TPR, ICP‐AES, XRD, and TGA. The nature of the formed cobalt species is dependent upon the number of amine groups in the organosilane molecules, due to the strength of the complexation. Only one amine group in the silane molecule leads to precipitation of Co3O4 particles during calcination, while two or more amine groups lead to the formation of cobalt silica at the surface. The obtained amount of precipitated cobalt in the samples is also dependent upon the number of amine groups and on the chain length of the silane molecules and the pore structure on the mesoporous material. 相似文献