Synthesis Of Silanes Research Articles

Promising Catalyst for Chlorosilane Dismutation

Currently, the most common method of silane synthesis for electronics and photovoltaics is trichlorosilane dismutation. Therefore, an experimental study of the kinetics of the dismutation reaction of chlorosilanes is of scientific and practical interest. A catalyst has been proposed that allows the dismutation reaction to be carried out in a wide range of temperatures and pressures. Both kinetic and thermodynamic data on the dependence of the rate of the dismutation reactions of trichlorosilane, dichlorosilane, and monochlorosilane on pressure were experimentally obtained. In addition, the dependence of saturated vapor pressure on temperature for monochlorosilane and dichlorosilane were also experimentally determined. Using the example of TCS, it was experimentally established that increasing the pressure to six atmospheres makes it possible to increase the specific productivity of the reactor by at least an order of magnitude due to the acceleration of the chemical reaction and the increase in the molar concentration of chlorosilanes in the vapor mixture. Consequently, it becomes possible to multiply the reactor’s load on the substance and, accordingly, the performance of the chlorosilane dismutation apparatus in general.

Synthesis of Silane Functionalized LDH-Modified Nanopowders to Improve Compatibility and Enhance Corrosion Protection for Epoxy Coatings.

Novel modified Zn-Al LDH/epoxy coatings are synthesized and applied to steel substrates, providing active corrosion protection and improved barrier properties. This protective coating is made by combining Epon 828 as a polymer matrix with modified layered-double-hydroxy (LDH) nanoparticles acting as corrosion inhibitor containers. To synthesize the coatings, nitrate was intercalated into Zn-Al-LDH layers through an aqueous co-precipitation method to obtain Zn-Al LDH-NO3, and decavanadate replaced nitrate within the LDH layers through an anion exchange process to obtain Zn-Al LDH-(V10O28)6-. The intercalated LDH was functionalized by silanization with (3-aminopropyl)triethoxysilane (APTES) to increase the compatibility of the LDH inhibitor nanocontainers with epoxy resin and produce a protective coating. To protect the mild steel substrate, functionalized LDH nanopowders were dispersed into the epoxy resin, mixed with a polyamide hardener (Epikure 3571), and applied and cured to the metal surface. Surface morphology, structure, and chemical composition were determined for the modified LDH nanopowders using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Corrosion protection of the coating system was studied using long-term immersion testing and potentiodynamic polarization studies in a 3.5 wt.% NaCl solution.

Broadband photodetectors from silane-passivated CsPbBr3 nanocrystals by ultrasound-mediated synthesis.

Perovskite nanocrystals have excellent optical properties but suffer from environmental instability and production up-scaling which limit their commercial application. Here, we report the gram-scale ultrasound-mediated synthesis of silane passivated CsPbBr3 nanocrystals using (3-aminopropyl) triethoxysilane (APTS) as the primary surface ligand surface. The surface engineering endowed the CsPbBr3@SiOR NCs with extended environmental stability, a narrow emission bandwidth and a high photoluminescence quantum yield (PLQY > 75%). Thanks to these excellent optical properties, high-efficiency lateral and vertical photodetectors were fabricated. In particular, the layered vertical photodiode composed of ITO/Ga2O3/CsPbBr3/Au exhibited a broadband photoresponse from 350-700 nm with a responsivity peaking at 44.5.1 A W-1 and specific detectivity above 1013 Jones when illuminated at 470 nm wavelength and biased at +5 V. These results correspond to the best-in-class performance perovskite nanocrystal PD and confirm the extraordinary potential of CsPbBr3@SiOR for the development of efficient optoelectronic devices.

Synthesis of silane- and quaternary ammonium-bearing copolymers and application as a coating resin on cotton fabric.

In this study, silane and quaternary ammonium functional methacrylate monomers were synthesized and used to construct a copolymer using an emulsion polymerization technique to control the reaction rate. The copolymer was then designed using different ratios of silane and quaternary ammonium groups to investigate the relationship between the structure and properties. The presence of the ethoxy silane group in the copolymer series provided covalent bonding through the silanol group onto cotton fabric. The presence of cationic groups also helped to cover the fabric surface. After coating the cotton textile fabric, the resistance of the dye on the fabric surface to friction was assessed and tests were conducted on washing, rubbing, water, and light fastness. Finally, the textile surfaces were investigated for their antibacterial activity against Staphylococcus aureus and Escherichia coli. It was observed that the copolymer series showed >99% killing efficiency against S. aureus but had no effect on E. coli.

A strategy for synthesis of silane terminated polyether triggered by click reaction and its application in preparation of modified silane sealants

A new hydroxy-silane coupling agent was synthesized from 3-butene-1-alcohol and mercaptopropyl-3-methoxysilane based on a click reaction between double bonds and sulfhydryl groups and was successfully used in the synthesis of silane-modified polyether (STPE). The effect of molecular weight of polypropylene glycol (PPG) on the properties of silane-modified polyether was studied. It was found that with the increase in PPG molecular weight, the initial thermal decomposition temperature and hardness of STPE elastomers decreased, but the molecular structure hardly changed. In addition, with the increase in molecular weight, the elongation at break of the elastomer will gradually increase, but the tensile strength of the elastomer does not change much. When the molecular weight reaches 20 000 g/mol, the resin with a viscosity of 1.6 × 105 mPa s can be obtained, and the elongation at break of the cured elastomer reaches 383.4% and the tensile strength is 0.25 MPa. After the STPE resin was prepared into a silane modified sealant, the tensile strength reached 1.31 MPa and the elongation at break reached 406.2%, which had the best mechanical properties among the prepared sealants. This shows that the sealant prepared from high molecular weight resin has stronger mechanical properties, which provides a new idea for the preparation of sealants.

Synthesis of biomass-based adsorbent from rice husk ash for copper ions adsorption

To solve the problems of low utilization of agricultural waste rice husk and heavy metal pollution, this investigation prepared a cheap copper ion adsorbent using rice husk ash (RA). The maximum Cu2+ adsorption capacity was 19.8 mg/g. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and surface area and porosity analyses were used to characterize the composition and structure of the material of silica-depleted rice husk ash (SDRA). The thermodynamics and kinetics of Cu2+ adsorption by SDRA were studied for their relevance to the adsorption mechanism. The adsorption of copper ions by SDRA was in accordance with the Langmuir model and the pseudo-second-order kinetic model. Furthermore, the increases in specific surface area and oxygen-containing functional groups following silica removal were primarily responsible for SDRA’s enhanced adsorption ability. And this is the first time that Cu2+ adsorbent has been prepared from the by-product of the synthesis of silane from rice husk ash. So, its synthesis cost is very low. Moreover, the preparation technique of SDRA is a revolutionary method of adsorbent creation that is both economical and environmentally benign.

Thermodynamics and Kinetics of the Reaction of Catalytic Dismutation of Chlorosilanes in the Vapor Phase in the Temperature Range of 353–393 K

Currently, the most common method of silane synthesis for electronics and photovoltaics is trichlorosilane (TS) dismutation. TS dismutation proceeds in the form of a reactions cascade, therefore its study is of both practical and scientific interest. The results of calculating the equilibrium composition of the reaction mixture in the vapor phase based on literature data from various sources were not reliable. Therefore, the dependence of the composition of the reaction mixture on the time of contact of the TS vapor with the catalyst under static conditions was experimentally investigated. The stationary composition of the mixture, close to equilibrium, was determined. A good agreement of the obtained results with the literature data in one of the sources was shown. The kinetics of the dismutation reaction of TS and dichlorosilane (DCS) was carried out by the flow method. As a result of regression analysis of experimental data, the rate constants of the direct and reverse dismutation reactions of TS, DCS, and monochlorosilane (MSC) were obtained. The rate constants were used to calculate the equilibrium composition of the reaction mixture. A good agreement between the calculated and experimental data was shown.

Sterically congested boronate and silane synthesis via electronically controlled protoboration and protosilylation

Multi-functionalized tertiary/secondary boronates and silanes have found wide applications in areas spanning organic synthesis, advanced material development, and pharmaceutical research. Effective access to these versatile motifs via protoboration/silylation of allenes remains unfulfilled. Capitalizing on the fluorine effects, here we report copper-catalyzed protoboration/silylation of gem -difluoroallenes, which shows an abnormal reactivity profile. In stark contrast to the conventional paradigms of allene functionalization reactions, which are often subjected to the steric-control mode for more facile reaction initiation on lower-substituted double bonds, the present reaction displays a virtually reversed regioselectivity for the more sterically congested π system. The synergistic LUMO-lowering perturbation and stabilization of nascent organocopper by fluorine substituents are deemed critical for guaranteeing the high fidelity of the present transformation. We not only apply this developed methodology to the late-stage modification of compounds derived from natural products but also highlight the utility of the obtained gem -difluoroalkenes in further synthetic elaborations. Easy access to congested boronate/silane via protoboration/silylation of allenes Efficient synthesis of versatile and bioactive gem -difluoroallylboronates and silanes Fluorine effects induced reversed regioselectivity for more congested π system Late-stage modification of complex compounds and derivatization of obtained products Conventional paradigms of allene functionalization are often subject to steric control for more facile reaction initiation on lower-substituted double bonds. Wang et al. present, to the best of their knowledge, the first example of tertiary/secondary boronate/silane construction via copper-catalyzed protoboration/silylation of gem -difluoroallenes, which displays a reversed regioselectivity for the sterically more congested π system.

Large scale synthesis of silane functionalized near-superhydrophobic aluminium hydroxide particles via facile surface grafting technique

Herein, we report a facile, large-scale synthesis approach to develop near-superhydrophobic crystalline single phase aluminium hydroxide (Al(OH)3/AH) particles via surface-grafting mediated functionalization using vinyltrimethoxysilane. The obtained XRD pattern and ATR-IR spectrum of the functionalized-AH (F-AH) showed the characteristic peaks corresponding to the existence of silane. The room temperature water contact angle (WCA) measurements revealed that the hydrophilic surface of AH (32.2°) is switched to near-superhydrophobic surface after the functionalization with WCA of 137.4°. Furthermore, the temperature dependent WCA studies at lower (∼10 °C), middle (∼50 °C) and higher temperatures (∼80/90 °C) showed that the silane-functionalization is stable and provides temperature independent near-superhydrophobic surface.

Nickel-Catalyzed Synthesis of Silanes from Silyl Ketones.

An unprecedented nickel-catalyzed decarbonylative silylation via CO extrusion intramolecular recombination fragment coupling of unstrained and nondirecting group-assisted silyl ketones is described. The inexpensive and readily available catalyst performs under mild reaction conditions and enables the synthesis of structurally diverse arylsilanes, including heterocyclic and natural product derivatives.

Synthesis of Silane Functionalized Graphene Oxide and Its Application in Anti-Corrosion Waterborne Polyurethane Composite Coatings

In this study, novel silane functionalized graphene oxide (PVSQ-GO) composite material is synthesized through the hydrolysis condensation reaction of vinyl triethoxysilane monomers occurred at the surface of graphene oxide. Results obtained from FTIR, Raman, X-ray photoelectronic spectroscopy (XPS), XRD and TGA measurements reveal that polyvinyl sesquisiloxane microspheres adhere to graphene oxide lamellae in the form of chemical bonds. Meanwhile, it is intuitive that abundant polyvinyl sesquisiloxane microspheres stick to the surface of graphene oxide and increase the thickness of the flake. Modified graphene oxide changes from hydrophilicity to hydrophobicity were owing to the existence of polyvinyl sesquisiloxane microspheres on the surface of graphene oxide (GO). PVSQ-GO composite exhibited good dispersion in eco-friendly waterborne polyurethane coating. Electrochemical impedance spectroscopy manifested that the anti-corrosion performance of waterborne polyurethane (WPU) coating embedded at 0.5 wt.% PVSQ-GO composite improved effectively. Tafel curves reveal that 0.5 wt.% PVSQ-GO/WPU coating specimen shows the lowest corrosion rate of 8.95 × 10−5 mm/year when compared with the other coating specimens. The good anti-corrosion abilities of PVSQ-GO composite coating can be interpreted as the good compatibility between PVSQ-GO composite and waterborne polyurethane, however, the intrinsic hydrophobicity of PVSQ-GO composite is beneficial to inhibit the permeation of corrosive medium and thus slows down the corrosion rate.

Zwitterionic–polyurethane coatings for non-specific marine bacterial inhibition: A nontoxic approach for marine application

The present work reports synthesis and development of zwitterionic tri-block copolymer-polyurethane (ZTC-PU) coatings which are thermally stable and have hydrophobic properties which can be used for marine applications. The zwitterionic tri-block copolymer (ZTC) (poly(sulfobetaine methacrylate) - polydimethylsiloxane - poly(sulfobetaine methacrylate), polySBMA-block-PDMS-block-polySBMA) was synthesized by ATRP (atom transfer radical polymerization) method. Apart from this, the facile synthesis of silane functionalized acrylic polyol was formulated with 4,4′- Methylene dicyclohexyl diisocyanate (H12 MDI) for the development of polyurethane (PU) coatings. Different weight ratios of ZTC was incorporated in PU to obtain a zwitterionic tri-block copolymer-polyurethane (ZTC-PU) coatings. The ZTC-PU coating exhibit good thermal stability and hydrophobic property. The coating showed excellent non-specific marine bacterial inhibition property along with good stability against gram positive Staphylococcus aureus (S. aureus) and gram negative Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) microbial strains. This design method reveals the development of zwitterionic-polyurethane coatings with higher amount of zwitterionic moiety in the coating system, that will be efficient and eco-friendly technology for marine bio-fouling application.

Direct Conversion of Hydride- to Siloxane-Terminated Silicon Quantum Dots

Peripheral surface functionalization of hydride-terminated silicon quantum dots (SiQD) is necessary in order to minimize their oxidation/aggregation and allow for solution processability. Historically thermal hydrosilylation addition of alkenes and alkynes across the Si–H surface to form Si–C bonds has been the primary method to achieve this. Here we demonstrate a mild alternative approach to functionalize hydride-terminated SiQDs using bulky silanols in the presence of free-radical initiators to form stable siloxane (∼Si–O–SiR3) surfaces with hydrogen gas as a byproduct. This offers an alternative to existing methods of forming siloxane surfaces that require corrosive Si–Cl based chemistry with HCl byproducts. A 52 nm blue shift in the photoluminescent spectra of siloxane versus alkyl-functionalized SiQDs is observed that we explain using computational theory. Model compound synthesis of silane and silsesquioxane analogues is used to optimize surface chemistry and elucidate reaction mechanisms. Thorough ...

Design of a Multitask Reactive Distillation with Intermediate Heat Exchangers for the Production of Silane and Chlorosilane Derivates

Silane and chlorosilanes are essential materials for manufacturing silicon solar cells, glass microscope slides, oxidation masks, and corrosion-resistant films among other products. Monochlorosilane (SiH3Cl) and dichlorosilane (SiH2Cl2) are produced on a large scale as intermediates in the synthesis of silane (SiH4) by disproportionation of trichlorosilane (SiHCl3). However, seldom are they isolated due to the highly integrated nature of silane production, and the high commercial demand for silane relative to monochlorosilane and dichlorosilane. This study proposes a multitask reactive distillation (MTRD) column with intermediate heat exchangers that has the flexibility to switch between the production of SiH4, SiH3Cl, and SiH2Cl2 from the SiHCl3 disproportionation. Because the reactive distillation that separates SiH4 uses an expensive refrigerant, intermediate heat exchangers are installed to reduce the cost and energy consumption of expensive refrigerants in the optimized MTRD. Process simulation and m...

Synthesis Photosical Properties of Silicon-Containing Cross-Linked Polymer

Organic light-emitting materials in Organic Light-emitting Diodes(OLED) reserch in a very important posotion, the quality of materials directly affect the level of luminous efficiency of the device. We chose benzene 2,6-alkynyl, respectively, and tetrakis (4-bromophenyl) silane, tetrakis (3-bromophenyl) silane synthesis of new cross-linked polymer, the structure was characterized by solid NMR, by fluorescence chromatography UV crosslinking compound characterization of chromatographic performance in photophysical aspects may choose to add a new organic light-emitting material.

ChemInform Abstract: Synthesis of Silanes and Germanes with Polyunsaturated Aliphatic Substituents

Abstractvia hydrosilylation of alkynes followed by subsequent treatment with ethynylmagnesium bromide

Synthesis of silane functionalized sodium titanate nanotubes and their influence on thermal and mechanical properties of epoxy nanocomposite

Sodium titanate nanotubes (NaTiNTs) were prepared by hydrothermal method and functionalized with three different silane coupling agents. The existence of the chemical bond between silane molecules and nanoparticles was confirmed by scanning electron microscopy (SEM) equipped with electron dispersive X-ray spectroscopy (EDS) mapping, Fourier transform infrared (FTIR) spectroscopy, and simultaneous differential scanning calorimetry–thermogravimetric analysis (DSC-TGA). NaTiNTs before and after functionalization were characterized by X-ray diffraction (XRD) technique. Functionalized NaTiNTs were used to prepare epoxy-based nanocomposites with three different wt.% of nanofillers (1, 2, and 3 wt.% per epoxy). The thermal and mechanical properties of prepared nanocomposites were studied by DSC, DSC-TGA, and dynamic mechanical analysis (DMA). The obtained results were compared to the epoxy. The results showed that the glass transition temperature increased from 72 to 79 °C. Storage modulus increased by 10.4% at 3 wt.% nanotubes. From all results appropriate functionalized NaTiNTs were chosen and nanocomposites for determination of combustion properties by cone calorimeter were prepared (1, 3, and 5 wt.% of nanofiller per epoxy). Significant reduction of the heat release rate (HRR) depending on the inorganic particles loading was observed. The peak value for HRR was reduced by about 40% compared to the epoxy, while ignition time and total heat release (THR) are not significantly affected by the presence of the inorganic particles.

Synthesis and characterization of novel polar-embedded silica stationary phases for use in reversed-phase high-performance liquid chromatography

We have developed a series of new C10 dipeptide stationary phases via a simple and effective synthetic method. The preparation of the new phases involves the synthesis of silanes and the surface modification of silica. Chromatographic evaluations of these columns were performed using the Engelhardt, Tanaka, and Neue test mixtures. The applicability of these new stationary phases was also evaluated using a series of diagnostic probes including acids, bases or neutral compounds and several generic applications. These new C10 dipeptide stationary phases showed excellent hydrolytic stability over a wide pH range. Like other existing amide-embedded columns, these new stationary phases exhibit higher retention for polar and hydrophilic compounds and different selectivity as compared to conventional C18 columns. These new phases are compatible with 100% aqueous mobile phases, and also provide high column efficiency and good peak shapes for both acidic and basic compounds.

Synthesis of silanes and germanes with polyunsaturated aliphatic substituents

Hydrosilylation of alkynes R3MC≡CH (M = Si, Ge) afforded adducts whose subsequent treatment with ethynylmagnesium bromide gives polyunsaturated silanes and germanes R3MCH=CHSi(C≡CH)3. The latter can be subjected to the same transfomations to result in the unsaturated chain growth.

Formation of impurity Si2OH6 in silane synthesized from silicon tetrafluoride

The possibility of the reduction of hexafluorodisiloxane by calcium hydride in the synthesis of silane from silicon tetrafluoride has been studied. This reaction is shown to be not decisive for oxygen contamination of silane. The most likely reason for the appearance of impurity Si2OH6 in “fluoride” silane is the Ca(OH)2-catalyzed reaction of silane with trace water. The concentration of impurity Si2OH6 in silane at the stage of synthesis may be efficiently decreased by the preliminary purging of calcium hydride with a hydrogen (grade A) flow.