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Efficient removal of organic contaminant via activation of potassium persulfate by γ-Fe2O3/α-MnO2 nanocomposite. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kalan RE, McCool BA, Tripp CP. Supercritical Fluid Atomic Layer Deposition: Base-Catalyzed Deposition of SiO2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7170-7179. [PMID: 27338186 DOI: 10.1021/acs.langmuir.6b01669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An in situ FTIR thin film technique was used to study the sequential atomic layer deposition (ALD) reactions of SiCl4, tetraethyl orthosilicate (TEOS) precursors, and water on nonporous silica powder using supercritical CO2 (sc-CO2) as the solvent. The IR work on nonporous powders was used to identify the reaction sequence for using a sc-CO2-based ALD to tune the pore size of a mesoporous silica. The IR studies showed that only trace adsorption of SiCl4 occurred on the silica, and this was due to the desiccating power of sc-CO2 to remove the adsorbed water from the surface. This was overcome by employing a three-step reaction scheme involving a first step of adsorption of triethylamine (TEA), followed by SiCl4 and then H2O. For TEOS, a three-step reaction sequence using TEA, TEOS, and then water offered no advantage, as the TEOS simply displaced the TEA from the silica surface. A two-step reaction involving the addition of TEOS followed by H2O in a second step did lead to silica film growth. However, higher growth rates were obtained when using a mixture of TEOS/TEA in the first step. The hydrolysis of the adsorbed TEOS was also much slower than that of the adsorbed SiCl4, and this was overcome by using a mixture of water/TEA during the second step. While the three-step process with SiCl4 showed a higher linear growth rate than obtained with two-step process using TEOS/TEA, its use was not practical, as the HCl generated led to corrosion of our sc-CO2 delivery system. However, when applying the two-step ALD reaction using TEOS on an MCM-41 powder, a 0.21 nm decrease in pore diameter was obtained after the first ALD cycle whereas further ALD cycles did not lead to further pore size reduction. This was attributed to the difficulty in removal of the H2O in the pores after the first cycle.
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Affiliation(s)
- Roghi E Kalan
- Department of Chemistry, University of Maine , Orono, Maine 04469, United States
| | - Benjamin A McCool
- Laboratory for Surface Science and Technology, University of Maine , Orono, Maine 04469, United States
| | - Carl P Tripp
- Department of Chemistry, University of Maine , Orono, Maine 04469, United States
- Laboratory for Surface Science and Technology, University of Maine , Orono, Maine 04469, United States
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Deetz JD, Ngo Q, Faller R. Reactive Molecular Dynamics Simulations of the Silanization of Silica Substrates by Methoxysilanes and Hydroxysilanes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7045-7055. [PMID: 27351376 DOI: 10.1021/acs.langmuir.6b00934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We perform reactive molecular dynamics simulations of monolayer formation by silanes on hydroxylated silica substrates. Solutions composed of alkylmethoxysilanes or alkylhydroxysilanes in hexane are placed in contact with a hydroxylated silica surface and simulated using a reactive force field (ReaxFF). In particular, we have modeled the deposition of butyl-, octyl-, and dodecyltrimethoxysilane to observe the dependence of alkylsilyl chain length on monolayer formation. We additionally modeled silanization using dodecyltrihydroxysilane, which allows for the comparison of two grafting mechanisms of alkoxysilanes: (1) direct condensation of alkoxysilane with surface-bound silanols and (2) a two-step hydrolysis-condensation mechanism. To emulate an infinite reservoir of reactive solution far away from the substrate, we have developed a method in which new precursor molecules are periodically added to a region of the simulation box located away from the surface. It is determined that the contact angle of alkyl tails bound to the surface is dependent on their grafting density. During the early stages of grafting alkoxy- and hydroxysilanes to the substrate, a preference is shown for silanes to condense with silanols further from the substrate surface and also close to neighboring surface-bound silanols. The kinetics of silica silanization by hydroxysilanes was observed to be much faster than for methoxysilanes. However, the as-deposited hydroxysilane monolayers show similar morphological characteristics to those formed by methoxysilanes.
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Affiliation(s)
- Joshua D Deetz
- Department of Chemical Engineering, University of California , Davis, California 95616, United States
- Department of Chemistry and Chemical Engineering, Shanghai Jiao Tong University , Shanghai 200240, China
| | - Quynh Ngo
- Department of Chemical Engineering, University of California , Davis, California 95616, United States
| | - Roland Faller
- Department of Chemical Engineering, University of California , Davis, California 95616, United States
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Zins EL, Krim L, Lenormand H, Goddard JP, Fensterbank L. Study of interaction between NO radicals and Martin's spirosilane by means of IR spectroscopy. J Phys Chem A 2013; 117:3296-303. [PMID: 23534373 DOI: 10.1021/jp401177c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The matrix isolation method is used to record the IR spectrum of C18H8O2F12Si in the 4000-500 cm(-1) range. To gain an IR spectrum with a sufficient resolution, this technique was used with neon as the dilution medium at 5 K. The generated species were characterized by in situ fourier transform infrared (FT-IR) spectroscopy. Once the Martin's spirosilane 1 (C18H8O2F12Si) was characterized, its reactivity toward NO was investigated under the same experimental conditions (i.e., using neon as a dilution medium at 5 K). In this case, the use of neon at very low temperature leads to the formation of a chemically inert matrix in which the species are trapped and isolated from one another, thus hindering consecutive reactions. As a consequence, intermediates can be observed. This approach allowed us to characterize the NO adduct, leading to the formation of 1-(NO). Concentration effects as well as annealing experiments were carried out. In addition to this experimental approach, products were identified by using reference spectra. Our results proved that, in the dilute phase, the reaction between 1 and NO radicals leads to the formation of an adduct. This stable species can further react with NO to form a more stable compound: 1-(NO)2. This proves the ability of such species to trap NO.
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Affiliation(s)
- E L Zins
- Laboratoire de Dynamique, Interactions et Réactivité (LADIR, UMR CNRS 7075), Université Pierre et Marie Curie Case 49, 4 place Jussieu, 75252 Paris cedex 05, France.
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Gowri VS, Almeida L, Amorim T, Carneiro N, Souto AP, Esteves MF. Novel copolymer for SiO2 nanoparticles dispersion. J Appl Polym Sci 2011. [DOI: 10.1002/app.35068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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García N, Benito E, Guzmán J, de Francisco R, Tiemblo P. Microwave versus conventional heating in the grafting of alkyltrimethoxysilanes onto silica particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:5499-5506. [PMID: 20085329 DOI: 10.1021/la903743n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The scope of this work is the comparative analysis in terms of grafting rate, structure of the grafted layer, and wetting behavior of three series of silica nanoparticles modified with alkyltrimethoxysilanes by using conventional heating with and without acid catalysis, and microwave irradiation. A comprehensive characterization of the grafted layer by means of Fourier transform infrared (FTIR), microanalysis, and solid state NMR techniques has shown that microwave irradiation provokes a pronounced increase in the loading rate compared to conventional heating. This microwave effect is outstanding in the case of the reactions with methyltrimethoxysilane, because of the acceleration of the condensation rate. Moreover, solid state NMR spectra ((29)Si and (13)C) strongly suggest structural differences in the grafted layer obtained by the two heating sources. The wetting behavior of the modified nanoparticles was studied, concluding that these changes in the structure of the grafted layer induced by the synthetic procedure do not determine the values of the dynamic water contact angles.
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Affiliation(s)
- Nuria García
- Instituto de Ciencia y Tecnologia de Polimeros (CSIC), Juan de la Cierva, 3, 28006 Madrid, Spain
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Scully NM, Healy LO, O’Mahony T, Glennon JD, Dietrich B, Albert K. Effect of silane reagent functionality for fluorinated alkyl and phenyl silica bonded stationary phases prepared in supercritical carbon dioxide. J Chromatogr A 2008; 1191:99-107. [DOI: 10.1016/j.chroma.2008.02.052] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Revised: 02/12/2008] [Accepted: 02/15/2008] [Indexed: 11/27/2022]
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Ojeda M, Pérez-Alonso FJ, Terreros P, Rojas S, Herranz T, López Granados M, Fierro JLG. Silylation of a Co/SiO2 catalyst. Characterization and exploitation of the CO hydrogenation reaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:3131-7. [PMID: 16548568 DOI: 10.1021/la052980c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Several silylated- and nonsilylated Co/SiO2 catalysts have been prepared by reaction of the surface silanol groups with hexamethyldisilazane (HMDS). These samples have been characterized by means of N2 adsorption isotherms, solid-state nuclear magnetic resonance (29Si and 1H), X-ray photoelectron spectroscopy, thermogravimetric analysis, and diffuse reflectance IR spectroscopy. We have focused on the study of the silylated surface stability at high temperatures and in different atmospheres. The characterization techniques have shown that silica silylation after cobalt impregnation leads to a silylated SiO2 surface composed of hydrophobic Si-(CH3)3 species highly stable up to 600-650 K in both oxidizing and reducing atmospheres. However, X-ray diffraction and temperature-programmed reduction have shown that the hydrophobic nature of the silica surface does not affect the metal dispersion and its reducibility. The materials prepared in this way have been tested as catalysts for the Fischer-Tropsch synthesis reaction. The CO conversion reaction rate increased over the silylated catalyst, probably as a consequence of the higher number of available active sites because water adsorption over the catalyst surface is impeded. However, catalyst deactivation was not affected by the hydrophobic nature of the support, suggesting that carbon deposition is the more probable mechanism of cobalt-based catalyst deactivation during the Fischer-Tropsch synthesis.
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Affiliation(s)
- Manuel Ojeda
- Instituto de Catalisis y Petroleoquímica (CSIC), C/Marie Curie 2, 28049 Madrid, Spain
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Ferguson-McPherson MK, Low ER, Esker AR, Morris JR. Sorption of Dimethyl Methylphosphonate within Langmuir−Blodgett Films of Trisilanolphenyl Polyhedral Oligomeric Silsesquioxane. J Phys Chem B 2005; 109:18914-20. [PMID: 16853435 DOI: 10.1021/jp0521959] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trisilanolphenyl polyhedral oligomeric silsesquioxane (POSS) molecules are used to create well-ordered Langmuir-Blodgett films containing silanol groups that interact strongly with dimethyl methylphosphonate (DMMP), a commonly used simulant for the chemical warfare agent sarin. The interaction of DMMP within multilayer POSS films is studied by uptake coefficient and temperature-programmed desorption (TPD) measurements, as well as reflection-absorption infrared spectroscopy (RAIRS). Results indicate a low uptake probability; however, in a DMMP-saturated atmosphere, the organophosphonate molecules are capable of diffusing into and adsorbing within the films. TPD and RAIRS measurements reveal no evidence of DMMP decomposition within the film. Rather, DMMP is found to desorb molecularly with a desorption energy of 122 kJ/mol. RAIRS reveals that strong hydrogen-bonding interactions between the phosphoryl groups of the organophosphonate molecules and the silanol groups of the POSS molecules are responsible for the high sorption energy of the system.
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Péré E, Cardy H, Latour V, Lacombe S. Low-temperature reaction of trialkoxysilanes on silica gel: a mild and controlled method for modifying silica surfaces. J Colloid Interface Sci 2005; 281:410-6. [PMID: 15571696 DOI: 10.1016/j.jcis.2004.08.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Accepted: 08/11/2004] [Indexed: 11/18/2022]
Abstract
The room temperature reaction of 4-(triethoxysilyl)butyronitrile, 4-TBN ((C2H5O)3Si(CH2)3CN), on weakly hydrated silica samples pretreated at 393 K has been studied by desorption experiments and by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy at different aging times under various water partial pressures. The reaction is demonstrated by the decrease of desorption of 4-TBN with time and the simultaneous disappearance of the 2980 and 1394 cm(-1) signals in the DRIFT spectra, assigned to the CH3 moiety of the ethoxy functions. Water partial pressure is shown to have a crucial effect on the rate and efficiency of the process as, after 6 days, for samples kept at room temperature under vacuum, ca. 50% of the silane has reacted, while for those kept in a water-saturated atmosphere the silane reaction reaches 96%. Although the silane appears to be irreversibly bonded to the surface, no definite conclusion may be drawn from these preliminary results as to the nature of the bonding (grafting or coating). These samples are compared to modified silicas prepared according to conventional methods. The same extent of silane reaction (50%) is achieved for preadsorbed samples kept under vacuum and either cured at 473 K for 30 h or kept at room temperature for 6 days. A mild and controlled modification of silica by triethoxysilanes can thus be achieved by first physisorbing known amounts of the modifying silanes from an organic solvent on pretreated silica and then letting the samples mature for a few days at room temperature in a water-saturated atmosphere.
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Affiliation(s)
- E Péré
- Laboratoire de Chimie Théorique et de Physico-Chime Moléculaire, UMR CNRS 5624, Université de Pau, B.P. 1155, 64013 Pau Cedex, France
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Marrone M, Montanari T, Busca G, Conzatti L, Costa G, Castellano M, Turturro A. A Fourier Transform Infrared (FTIR) Study of the Reaction of Triethoxysilane (TES) and Bis[3-triethoxysilylpropyl]tetrasulfane (TESPT) with the Surface of Amorphous Silica. J Phys Chem B 2004. [DOI: 10.1021/jp036148x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michelle Marrone
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
| | - Tania Montanari
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
| | - Guido Busca
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
| | - Lucia Conzatti
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
| | - Giovanna Costa
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
| | - Maila Castellano
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
| | - Antonio Turturro
- Laboratorio di Chimica delle Superfici e Catalisi Industriale, Dipartimento di Ingegneria Chimica e di Processo, Università di Genova, P.le Kennedy, I-16129 Genova, Italy, Istituto per lo Studio delle Macromolecole ISMAC-CNR, Sezione di Genova, Via E. De Marini, 6, I-16149 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso, 31, I-16146 Genova, Italy
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Bakaev VA, Bakaeva TI, Pantano CG. A Study of Glass Surface Heterogeneity and Silylation by Inverse Gas Chromatography. J Phys Chem B 2002. [DOI: 10.1021/jp0215926] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. A. Bakaev
- Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802
| | - T. I. Bakaeva
- Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802
| | - C. G. Pantano
- Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802
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Pavlovic E, Quist AP, Gelius U, Oscarsson S. Surface functionalization of silicon oxide at room temperature and atmospheric pressure. J Colloid Interface Sci 2002; 254:200-3. [PMID: 12702443 DOI: 10.1006/jcis.2002.8565] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel method to derivatize silicon surfaces with 3-mercaptopropylsilane molecules has been developed and optimized. This method is based on an argon flow that increases the evaporation rate of the silane molecules by lowering the partial pressure of the silane molecules in gas phase above the liquid silane, at room temperature. X-ray photoelectron spectroscopy studies of the surfaces showed a dense monolayer coverage as well as hydrolysis of the silane methoxy groups. Atomic force microscopy was used to investigate the roughness of the surfaces after each step of the derivatization process. Since the final surface has a measured surface roughness of 0.19 nm, this method will be especially useful for further synthetic routes and advanced single molecule detection studies of interactions on surfaces as well as improvement of existing conventional techniques for surface derivatization and analysis.
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White LD, Tripp CP. Reaction of (3-Aminopropyl)dimethylethoxysilane with Amine Catalysts on Silica Surfaces. J Colloid Interface Sci 2000; 232:400-407. [PMID: 11097776 DOI: 10.1006/jcis.2000.7224] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The gas-phase reaction of (3-aminopropyl)dimethylethoxysilane (APDMES) with silica with and without amine catalysts has been studied using infrared spectroscopy. Evidence is provided that shows that the aminosilane initially adsorbs via hydrogen bonding of both ethoxy and aminopropyl moieties of the silane with the surface hydroxyl groups. As the reaction proceeds, the number of silane molecules attached to the surface via a Si-O-Si linkage increases primarily at the expense of the number of H-bonded ethoxy groups. The conversion is due to a catalytic process involving the aminopropyl end of gaseous APDMES molecules. On the other hand, the H-bonded aminopropyl groups are less reactive and only a small portion of these groups participates in Si-O-Si bond formation. At the end of the reaction there remain about 50% of the adsorbed APDMES attached by the H-bonded aminopropyl group. Attempts to block the adsorption of the aminopropyl end through the use of the more strongly H-bonded triethylamine proved unsuccessful. The use of preadsorbed triethylamine or 1 : 10 mixtures of triethylamine/APDMES accelerates the reaction but in the end leads to the same final distribution of products on the surface. Copyright 2000 Academic Press.
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Affiliation(s)
- LD White
- Department of Chemistry and Laboratory for Surface Science and Technology, University of Maine, Orono, 04469, Maine
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White LD, Tripp CP. An Infrared Study of the Amine-Catalyzed Reaction of Methoxymethylsilanes with Silica. J Colloid Interface Sci 2000; 227:237-243. [PMID: 10860616 DOI: 10.1006/jcis.2000.6895] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A thin film infrared technique was used to investigate the reaction of methoxysilanes and amines with the silica surface. The low-frequency region contains bands due to Si-O-Si modes that are used to distinguish between hydrogen-bonded and chemisorbed species. It is shown that the competitive adsorption of amines and CH(3)OSi(CH(3))(3) differs from the results obtained using (CH(3)O)(2)Si(CH(3))(2) or (CH(3)O)(3)SiCH(3). The monomethoxysilane does not displace preadsorbed triethylamine whereas the triethylamine is displaced from the surface by both (CH(3)O)(2)Si(CH(3))(2) and (CH(3)O)(3)SiCH(3). In the reverse sequence, the triethylamine displaces all three methoxysilanes on the surface. When 1:1 mixtures of methoxysilanes and triethylamine (or propylamine) are co-added to silica, the amine preferentially adsorbs and is only displaced by subsequent chemisorption of the silane. The implication of these results for using a two-step amine-catalyzed reaction of methoxysilanes on silica is discussed. Copyright 2000 Academic Press.
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Affiliation(s)
- LD White
- Department of Chemistry and Laboratory for Surface Science and Technology, University of Maine, Orono, Maine, 04469
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