Preparation of monolithic gels from silicon halides by a non-hydrolytic sol-gel process

doi:10.1016/S0022-3093(05)80505-8

Journal of Non-Crystalline Solids

Volume 146, 1992, Pages 301-303

https://doi.org/10.1016/S0022-3093(05)80505-8 Get rights and content

Reactions of organic oxygen compounds, such as ter-butanol, benzylalcohol, dibenzylether and benzaldehyde, with silicon halides provide a novel non-hydrolytic sol-gel route to silica.

References (13)

C. Sanchez et al.
J. Non-Cryst. Solids
(1988)
C.J. Brinker et al.
Sol-Gel Science: the Physics and Chemistry of Sol-Gel Processing
(1990)
D. Ridge et al.
J. Chem. Soc.
(1949)
W. Gerrard et al.
J. Chem. Soc.
(1951)
W. Gerrard et al.
J. Chem. Soc.
(1952)
W. Gerrard et al.
Research
(1954)

There are more references available in the full text version of this article.

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Solvothermal synthesis of oxide nanoparticles involves nonhydrolytic reaction processes with metal halide precursors and alcohol as solvent as well as the oxygen source. The preparation for several metal oxides via the reaction between high valence metal chlorides with benzyl alcohol has been reported by Vioux et al. [27–29]. Subsequently, Niederberger et al. [23, 24, 30, 31] extended this approach to prepare other high valence metal oxides and compounds and focused on using benzyl alcohol solvent.
The buildings in tropical climate like Singapore get excessive heat gain throughout the year. Passive cooling can be achieved with IR-shielding coating by blocking the IR radiation from solar light. In this work, antimony-doped tin oxide (ATO) nanocrystals with diameter of 10 nm were synthesized by solvothermal method. The Sb dopant concentration in ATO nanoparticles was optimized towards enhanced IR shielding properties. Sol–gel precursor was formulated with silanes and ATO nanocrystals. Transparent IR shielding coatings were coated on glass for smart window. The optical and IR shielding performance of the coatings were evaluated. By incorporating smaller ATO nanocrystals synthesized by solvothermal synthesis, the IR shielding performance of the coating was greatly improved as compared to that using larger commercial ATO nanoparticles. The IR shielding coating with synthesized ATO nanocrystals can block more than 90% IR while it can maintain more than 80% transmittance at the visible range. The solar heat gain coefficient (SHGC or G-value) of the coating with 10 wt.% synthesized ATO nanocrystals is 0.68 for single layer structure, and decreases to 0.53 with double glazing structure while maintaining good visible transmittance of 60%.
Mesoporous mixed oxide catalysts via non-hydrolytic sol-gel: A review
2013, Applied Catalysis A: General
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This non-hydrolytic condensation takes place at mild temperature (80–150 °C) for a wide variety of metals and transition metals (Ti, Al, Sn, Zr, V, Co, W, Mo, Nb, etc.), even with simple primary or secondary R groups. The reactivity of silicon is much lower, and catalysis by Lewis acids (e.g. FeCl3, AlCl3, ZrCl4) is required [43], unless tertiary or benzylic R groups are used [22]. The alkoxide groups may be formed in situ by reaction of the chloride with an ether (usually diisopropyl ether, iPr2O) (Eq. (2)) or with a primary or secondary alcohol (Eq. (3)), allowing the synthesis of oxides by reaction of cheap chloride precursors with ethers (“ether route”) or alcohols (“alcohol route”).
Despite the enormous amount of research dedicated to this topic in the last 20 years or so, there is still a need for a general, cost-effective methodology allowing the synthesis of mesoporous mixed oxide catalysts.
This review deals with the synthesis and catalytic applications of mixed oxides prepared by the non-hydrolytic sol–gel (NHSG) process based on the reaction of chloride precursors with ether or alkoxide oxygen donors. This NHSG process offers simple, one-step syntheses of mixed oxides with well-controlled compositions and non-ordered mesoporous textures, avoiding the use of supercritical drying or templates. Over the last decade, this process has been used to prepare various mesoporous mixed oxide catalysts, which showed real potential in major reactions such as partial and total oxidation, reduction of NO_x, alkene metathesis, or alkylation.
The main reactions involved in this NHSG process and the characteristics of the resulting mixed oxides are described in the first part of this review, underlining the decisive advantages in terms of simplicity and of control (in terms of composition, homogeneity or texture) offered by this process. In a second part, the literature dealing with mixed oxide catalysts prepared by this NHSG method is exhaustively reviewed and the catalytic performance of NHSG catalysts is compared, whenever possible, to that of catalysts with similar compositions prepared by other methods.
The excellent catalytic performances of NHSG-catalysts (notably SiTi, TiV and SiAlMo catalysts) compared to state-of-the art aerogels or ordered mesoporous materials evidences the potential of this sol–gel method, which should open the door to the synthesis of improved catalysts and to the discovery of new catalysts.
Direct alkoxysilylation of alkoxysilanes for the synthesis of explicit alkoxysiloxane oligomers
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Direct alkoxysilylation, which is a powerful tool to provide explicit alkoxysiloxanes, is developed and its versatility is investigated. Siloxane pentamers Si[OSiR¹(OMe)₂]₄ having various functional groups (R¹ = methyl, vinyl, phenyl, chloropropyl and n-butyl groups) were successfully obtained by direct alkoxysilylation of Si(OR)₄ (R = t-Bu, CHPh₂). Thus, the versatility of the reaction is confirmed on organic functional groups R¹. Functional group tolerance of the reaction is discussed on the basis of electronegativity of the R¹ groups. Alkoxysilylation of Si(Ot-Bu)₂(OMe)₂ and Si(Ot-Bu)(OMe)₃ selectively gives trimer (MeO)₂Si[OSiMe(OMe)₂]₂ and dimer (MeO)₃SiOSiMe(OMe)₂, respectively. Thus, the feasibility on siloxane structure is also confirmed. Various siloxane compounds are synthesized by this newly developed reaction for the first time.
Photo-cured epoxy networks reinforced with TiO<inf>2</inf> in-situ generated by means of non-hydrolytic sol-gel process
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The most important and the most used are the condensations through alkyl halide elimination and/or ether elimination [10,11] as follows: Metal halide–alcohol reactionMXm + n ROH → M(X)m−n(OR)n + n HXCondensation M–OR + RO–M → M–O–M + R–O–R (by ether elimination)and/or [12–14] M–OR + X–M → M–O–M + R–X (by alkyl-halide elimination) In principle, the NHSG route offers access to a range of organic–inorganic nanocomposite products similar to those accessible using the hydrolytic route.
Suspensions of titania nanoparticles in benzyl alcohol were synthesised from TiCl₄ by means of non-hydrolytic sol–gel (NHSG) process. The stable suspensions were mixed with an aliphatic epoxy resin and subsequently photo-polymerised in the presence of a cationic photo-initiator to produce transparent composite films. The presence of titania didn’t influence significantly the polymerisation rate, while a progressive decrease in the maximum value of epoxy groups conversion was observed by increasing the titania content. Gel content analysis demonstrated that all organic species (benzyl alcohol and corresponding by-products) were covalently linked to the epoxy network, suggesting that both ‘active chain end’ and ‘activated monomer’ mechanisms were active during the propagation step in the cationic ring-opening polymerisation. The presence of titania increased significantly both glass transition temperature and modulus (in the rubbery region) confirming the reinforcing and stiffening effect due to both the presence of inorganic nanofillers and, most importantly, a higher cross-linking density of the composite material with respect to the pristine epoxy matrix. Nano-indentation and scratch tests also showed a systematic increase of hardness and scratch resistance by increasing the filler content.
A Non-Hydrolytic Sol–Gel Route to Organic-Inorganic Hybrid Polymers: Linearly Expanded Silica and Silsesquioxanes
2023, Gels
Micro to mesoporous SiO<inf>2</inf>xerogels: the effect of acid catalyst type in sol–gel process
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Letter To The EditorPreparation of monolithic gels from silicon halides by a non-hydrolytic sol-gel process

J. Non-Cryst. Solids

Sol-Gel Science: the Physics and Chemistry of Sol-Gel Processing

J. Chem. Soc.

J. Chem. Soc.

J. Chem. Soc.

Research

Letter To The Editor
Preparation of monolithic gels from silicon halides by a non-hydrolytic sol-gel process