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Stable selenenyl-chlorophosphines, bearing a silylalkyl group, were synthesized. Subsequent treatment with Lewis acids such as AlCl3 afforded the corresponding phosphaalkenes. A reaction mechanism that proceeds through an intramolecular 1,2-elimination of chlorosilane was proposed.

A sterically demanding TBS-substituted oligosilane (4, TBS = t-butyldimethylsilyl) was stepwisely formed by reactions of oligosilanyl potassium compound and the corresponding chlorosilane. Although a well-established method, the ring closure reaction of compound 4 in the presence of t-BuOK and 18-Cr-6 with SiX4 (X = Cl, Br) failed. The silyl potassium compound was then transformed to silyl Grignard compound 5, which can be used to react with SiX4 to give the dihalocyclopentasilanes (6, X = Cl; 7, X = Br) successfully. The molecular structures of 3–7 have been confirmed by X-ray single-crystal analyses.

Selected area Cu-catalyzed vapor–liquid−solid growth of SiGe microwires is achieved using chlorosilane and chlorogermane precursors. The composition can be tuned up to 12% Ge with a simultaneous decrease in the growth rate from 7 to 1 μm min–1. Significant changes to the morphology were observed, including tapering and faceting on the sidewalls and along the lengths of the wires. Characterization of axial and radial cross sections with transmission electron microscopy revealed no evidence of defects at facet corners and edges, and the tapering is shown to be due to in situ removal of catalyst material during growth. X-ray diffraction and transmission electron microscopy reveal a Ge-rich crystal at the tip of the wires, strongly suggesting that the Ge incorporation is limited by the crystallization rate.

Chlorosilanes are used abundantly at high temperatures in the production of ultra-pure silicon and silicon containing materials. The presence of both chlorine and silicon presents a unique corrosion environment for the metallic materials that must handle these compounds. It is known that in chlorosilane environments, 316L can form either a protective metal silicide layer or a volatile metal chloride layer on the substrate. However, it is not known what dependence this surface reaction has on temperature, time, or gas composition. In this study, AISI 316L stainless steel was exposed to vaporized silicon tetrachloride (STC, SiCl4), pure hydrogen (H2), and anhydrous hydrogen chloride (HCl) at temperatures (>350°C), times (1-200 hours), and compositions relevant to industrial processes. Metal silicide and metal chloride formation was evaluated using surface and gravimetric analysis, with metal silicide formation causing a gain in sample mass and metal chloride formation causing a loss in sample mass. It was revealed that the transition between chloride and silicide formation depends on time of exposure, temperature, and mole fraction of HCl present in the gas stream. Lastly, some discussion is provided on the underlying mechanisms of silicide and chloride formation, and how to prevent excessive corrosion in industrial applications.

One-part geopolymers were synthesized from two different silica materials (a silica-rich residue from chlorosilane production and a commercial microsilica) and sodium aluminate at three different SiO2/Al2O3 ratios and a nominal water/solids ratio of 0.5. The degree of reaction of the silica in the cured geopolymers (i.e. the fraction of silica dissolved to form aluminosilicates and minor products) was determined using two different methods: chemical attack with HCl to dissolve the reaction products and evaluation of peak areas of 29Si MAS NMR spectra. It was found that the degree of reaction of the silica decreases with increasing the silica content of the starting mix, and that it is almost constant after 1 day of curing and almost independent from the kind of starting silica. From the results of the NMR-based method, the mean SiO2/Al2O3 ratio of the reaction products (aluminosilicates and minor products) can be estimated to be ca. 2.0, nearly independent of the starting composition of the geopolymers. The dissolution method is biased, but of sufficient precision to be useful for following changes of the degree of reaction. Major crystalline phases in the cured geopolymers are zeolite A and/or hydrosodalite. Depending on the starting composition, the relative amounts of these zeolites vary; additionally, sodalite (only for the residue from chlorosilane production with >1 wt% Cl-), faujasite, and zeolite EMT can appear in the geopolymers. The 29Si and 27Al MAS NMR results indicate mainly Si(4Al) and Al(4Si) sites, in line with the presence of zeolite A, hydrosodalite, sodalite, and geopolymeric gel of comparatively low SiO2/Al2O3 ratio.

An exfoliated clay−polymer nanocomposite was prepared by surface-initiated ring opening metathesis polymerization (SI-ROMP) of norbornene on a montmorillonite (MMT) clay with a modified surface. Utilizing the hydrothermal-silylation reaction between a norbornenyl-bearing chlorosilane agent and silanol groups of the MMT clay, we were able to bind a metal alkylidene catalyst to the surface in order to grow poly(norbornene) chains directly from the surface using ROMP. Our approach produced nanocomposites having poly(norbornene) chains that are covalently attached to the inorganic substrate, as opposed to most conventional polymer-clay composites that have ionically tethered chains (via the ammonium-based modifiers of the organoclay) or physically adsorbed polymers. POLYM. ENG. SCI., 55:2349–2354, 2015. © 2015 Society of Plastics Engineers

To improve the antioxidative efficiency of 2-mercaptobenzimidazole (MB) and strengthen the interaction between halloysite nanotubes (HNTs) and natural rubber (NR), HNTs supported 2-mercaptobenzimidazole (HNTs-s-MB) was prepared by reacting MB with chlorosilane modified HNTs (m-HNTs). FTIR, XPS and TGA confirmed that MB was chemically bonded onto the surface of HNTs. HNTs-s-MB could be homogeneously dispersed in the NR matrix and there was a strong interfacial interaction between HNTs-s-MB and NR, leading to the better mechanical performances of NR/HNTs-s-MB nanocomposites than those of NR/HNTs nanocomposites. Based on the measurements of the thermo-oxidation activation energy of NR/HNTs-s-MB and NR/m-HNTs/MB nanocomposites containing equivalent antioxidant component, it was found that the antioxidative efficiency of HNTs-s-MB was superior to that of the corresponding low molecular MB owing to the much lower migration and volatility of HNTs-s-MB than those of MB.

High temperature chlorosilane gas streams are used throughout the photovoltaic, polycrystalline silicon, and fumed silica industries as a means to purify, refine, and produce silicon species. These gas streams create a unique corrosion environment due the ability of many metals to form metal-silicides or metal-chlorides depending on the atmosphere. In this study, a method was developed to test AISI 316L stainless steel in a high temperature (550°C) chlorosilane environment by exposing the samples to variable amounts of hydrogen, hydrogen chloride (HCl), and silicon tetrachloride (STC). In this method, the mole fraction of HCl was adjusted to investigate when the transition from silicide formation to chloride formation occurs. Gravimetric and surface analysis was performed before and after exposure, revealing that without any HCl in the system, there was predominately metal silicide formation. As the HCl mole fraction was increased up to about 0.027, there was increasing metal chloride formation and decreasing silicide formation. Above an HCl mole fraction of 0.027, there was predominately chloride formation. The silicide formation was accompanied with a net mass gain due to the relatively low vapor pressure of iron silicide and nickel silicide species. Chloride formation was accompanied with a net mass loss due to the reactive evaporation of iron, nickel, and some chromium with chlorine. Lastly, the implications of this study as they relate to industrial processes are discussed.

With the recent advances in the development of novel protein based therapeutics, controlled delivery of these biologics is an important area of research. Herein, we report the synthesis of microparticles from bovine serum albumin (BSA) as a model protein using Particle Replication in Non-wetting Templates (PRINT) with specific size and shape. These particles were functionalized at room temperature using multifunctional chlorosilane that cross-link the particles to render them to slowly-dissolving in aqueous media. Mass spectrometric study of the reaction products of diisopropyldichlorosilane with individual components of the particles revealed that they are capable of reacting and forming cross-links. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were also used to confirm the functionalization of the particles. Cross sectional analysis using focused ion beam (FIB) and EDS proved that the functionalization occurs throughout the bulk of the particles and is not just limited to the surface. Circular dichroism data confirmed that the fraction of BSA molecules released from the particles retains its secondary structure thereby indicating that the system can be used for delivering protein based formulations while controlling the dissolution kinetics.

In this work we report the synthesis of α,ω-telechelic poly(dimethylsiloxane)s (α,ω-PDMS) by employing a novel bifunctional initiator obtained from a commercially available siloxane precursor, diglycidylether-terminated poly(dimethylsiloxane) (PDMS-DGE). The synthetic strategy was easily followed by different colour changes, and involved the high-vacuum reaction of sec-Bu-Li+ with 1,1′-diphenylethylene (DPE) to afford the addition adduct (bright red) that was subsequently reacted with PDMS-DGE, promoting the nuclephilic ring-opening from epoxide-end chains. The resulting bifunctional initiator (light green) was then employed to polymerize hexamethyl(cyclotrisiloxane) monomer (D3) by using conventional anionic polymerization (from light green to pale yellow). From suitable terminating agents, silane (-SiH), vinyl (-CH≤CH2), hydroxy (-OH), and even methacryloyl α,ω-PDMS were obtained. 1H NMR and FT-IR analyses confirmed the presence of the targeted functional groups in the resulting polymers. However, a careful siliconization procedure should be performed over glass surfaces during the fractionation of chlorosilane ampoules in order to avoid the presence of silanol moieties that decrease end-capping efficiency. This fact was observed not only from NMR but also from size exclusion chromatography (SEC) analyses, since narrow molar masses distributions (1.15 ≤ Mw/Mn ≤ 1.3) and a good control over the resulting molar masses were observed. Fil: Lencina, María Malvina Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina Fil: Redondo, Franco Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Müller, Camila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Hanazumi, Vivina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Vitale, Cristian Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Ninago, Mario Daniel. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas A la Industria. Departamento de Ing. Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Vega, Daniel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina Fil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina Fil: Ciolino, Andrés Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina

The Noyori catalyst RuCl2(R-Binap)(dmf)n has been successfully encapsulated in C-FDU-12 by using the active chlorosilane Ph2Cl2Si as the silylating agent. 31P-NMR results show that there is no strong interaction between the molecular catalyst and the solid support, thus the encapsulated molecular catalyst could move freely in the nanoreactor during the catalytic process. The solid catalyst exhibits high activity and enantioselectivity for the asymmetric hydrogenation of a series of β-keto esters due to the preserved intrinsic properties of RuCl2(R-Binap)(dmf)n encapsulated in the nanoreactor. The solid catalyst could be recycled by simple filtration and be reused at least four times.

A novel yet straightforward one-pot synthesis technique was developed to grow silica nanorods on the interior and exterior surfaces of a porous, inorganic scaffold. Growth of the rods on the surface, versus in the bulk, was achieved by functionalizing the surface with chlorosilane molecules, which allowed the emulsion droplets in which the nanorods grow to anchor to the surface. Rods of 100–200 nm diameter and up to 2 μm in length could be grown uniformly over the surface with a typical surface density of 3 rods per μm2, resulting in an order-of-magnitude increase in the specific surface area (area per mass) of the porous material. It was also shown that the properties of the rods (e.g., size, surface density, shape) could be controlled by changing either the composition of the substrate material or the concentrations of key components in the reacting mixture. Furthermore, by selectively controlling the spatial location of the chlorosilane surface groups, the rods could be grown in specific locations inside the porous material.

A facile and efficient method has been developed for the preparation of seven-membered heterocycles 1,5-benzoxazepines by MeSiCl3/DMF-catalyzed domino reaction via the addition of in situ generated enamines to aldehydes . The advantages of this method are that it operates easily and achieves good yields for a broad scope of aldehyde substrates. And the corresponding products can be readily transformed to other categories of compounds, such as the hydrogenated products , which may have potential application in drug industry.

In this article, chlorosilane-modified ZSM-5 particles were incorporated into polydimethylsiloxane (PDMS) to form mixed matrix membranes (MMMs) for ethanol/water mixture separation via pervaporation (PV). The membranes were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and mechanical performance testing. The maximum loading and dispersion of ZSM-5 into PDMS were improved by chlorosilane modification. To evaluate the PV performance, the MMMs were used to separate an aqueous ethanol solution. The effect of zeolite loading and operational conditions on PV performance was investigated in detail. The separation factor of the composite membranes filled with modified ZSM-5 increased considerably versus unmodified membrane, while the total flux decreased to some degree. Of all the chlorosilane-modified membranes, dodecyltrichlorosilane modified ZSM-5 filled PDMS showed the best separation factor of 15.8 for ethanol. POLYM. COMPOS., 37:1282–1291, 2016. © 2014 Society of Plastics Engineers

Semiconductor silicon film is a widely used material in various fields including microelectronics, solar cells and power electronics. In industry, trichlorosilane gas 1‐3 is quite often used for producing silicon films by means of chemical vapor deposition (CVD), because the very high purity trichlorosilane is widely available at a reasonable price, and because its storage and use are easier and safer than the other silicon precursors. The siliconfilm deposition using chlorosilane gases has been studied for many years by various researchers. 1‐5 They mainly evaluated the chemical species and processes accounting for the deposition rate in order to improve the CVD processes and to design the CVD reactors. In a trichlorosilane-hydrogen system and in a cold wall system, trichlorosilane was shown to directly reach the silicon substrate surface for producing the silicon film. 5 Additionally, the silicon deposition rate could be sufficiently described following an Eley-Rideal surface reaction model. 5 Although SiCl2 was shown to be produced by the thermal decomposition of trichlorosilane in the gas phase of the cold wall environment, its amount was shown to be too low to influence the film deposition rate. However, from a different point of view for achieving a safe operation for the long-term use of the CVD reactor in industry, the by-product, called oily silane, 6 must be taken care. After the repetitive CVD operation for a month or more, an enormous amount of oily silaneoftenfillstheexhausttube.Thus,theexhausttubeisperiodically cleaned. However, this operation has several problems. The cleaning operation requires several hours. Additionally, the oily silane is burnable and sometimes explodes. 7 In order to avoid disastrous accidents, the conditions producing oily silane should be further studied relating to the SiCl2 formation, because the oily silane has been identified as polymerized SiCl2, 8 (SiCl2)n. (In detail, X-(SiCl2)n-Y. X and Y are endgroups).Additionally,whenthesiliconwaferdiameterisenlarged from 300 mm to 450 mm in the future, the by-product problem will become more serious due to the huge consumption of the precursor. Based on empirical information, 9 keeping the exhaust warm is considered to be effective for decreasing the oily silane deposition. Additionally, from the viewpoint of equilibrium between chlorosilanes and ambient gases, hydrogen is expected to play some role in decreasing SiCl2 in a chlorosilane-hydrogen system. Thus, the SiCl2 formation should be studied in detail. For this kind of studyby an experimental approach, an insitu monitoring technique is convenient, such as using the quadrupole mass spectra (QMS) analyzer 5 for the gas species analysis and the langasite crystal microbalance (LCM) 10 for measuring a significantly slow deposition. The combination of these tools is expected to reveal significantly weak and slow phenomena, like the oily silane deposition. ∗

A hydroxy-directed alkylation of an N,N-diethylarylamide using CIPE-assisted α-silyl carbanions (CIPE = complex-induced proximity effect) has been developed using a simple reagent combination of LDA (lithium diisopropylamide) and chlorosilane. A study of the mechanism, and the application of the procedure to an anionic Snieckus-Fries rearrangement for a highly efficient synthesis of the potent phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, are reported.

By making use of the catalytic potential of the iridium system [{Ir(μ-Cl)(CO)2}2]/NEt(i-Pr)2 in the synthesis of silyl-functionalized alkynes via silylative coupling of terminal alkynes/diynes with iodosilanes, we propose a new protocol allowing employment of various mono- and dichlorosilanes as reagents. The process is based on a sequence of two reactions occurring simultaneously: i.e., conversion of initial chlorosilane (SiR1nCl4–n) to the appropriate iodosilane via Cl/I nucleophilic substitution and its further conversion to a silylalkyne derivative ((SiR1n(C≡CR2)4–n) via iridium-catalyzed silylative coupling with terminal alkyne. Under optimum conditions, the method has proved to be effective and versatile in the conversion of a wide range of chlorosilanes to a rich portfolio of various corresponding alkynyl-functionalized silicon derivatives. Additionally, NMR studies of the equimolar reaction of a well-defined iridium(I) alkynyl precursor with Me3Si–I revealed that ≡Si–I bond activation in iodosilan...

A systematic study of “coffee-ring” formation dynamics was carried out using chemically and physically well-controlled substrates and colloids. Clean silicon wafers were reacted with tris(trimethylsiloxyl)chlorosilane in the vapor phase to yield molecularly smooth substrates with advancing and receding contact angles up to 84°/74° (θA/θR) and a constant hysteresis of 12 ± 2°. Monodisperse gold nanoparticles (AuNPs) of 15 nm in diameter were stabilized and functionalized with poly(vinyl alcohol) (PVOH) of 9 nm in thickness in aqueous solution. The evolution of contact angle and contact diameter of water and colloid-containing drops on clean and modified silicon wafers was assessed as sessile drops evaporated. PVOH-AuNPs in the colloid-containing drop increase the energy barrier for contact line depinning and the pinning force. There are up to four drying stages for colloid-containing drops, initial pinning, depinning, secondary pinning, and final evaporation. The contribution of each stage to evaporation depends on substrate receding contact angle. It is established in this study that the secondary pinning is unique for colloid-containing drops and is only observed on substrates with receding contact angles greater than 35°. “Coffee rings” are formed on all modified silicon wafers, but not on clean silicon wafers with contact angles of 0°/0°.

Tetrakis(trialkylsilyl) diphosphate (alkyl = Me, Et, iPr, tBu) can be obtained in quantitative yield by reacting commercial disodium dihydrogen diphosphate with the respective trialkyl chlorosilane in a triphasic system with formamide. The alkylsilane residues of the diphosphate silyl esters can be either partially or completely hydrolyzed without concurrent cleavage of the P–O–P bond of the diphosphate moiety. The method can be expanded to efficiently produce other persilylated or partially silylated phosphates and phosphites.

Solar energy has received considerable attention over the past few decades, due to its importance as a green and renewable energy. Low-cost solar-grade silicon production is critical for the widespread use of solar cells. Conventional routes (e.g., modified Siemens process: chlorosilane and hot filament) have still dominated the production of solar-grade silicon. The metallurgical route offers benefits in the productivity and cost, but efficient removal of boron is one of the most daunting challenges in front of us. This paper reviews thermodynamic and kinetic properties (solubility, diffusivity, diffusion coefficients, mass transfer rate, and activity coefficient) of boron and recent research topics (slag treatment, solvent refining, gas injection, plasma treatment, and acid leaching) for boron removal.

It is well known that dropwise condensation enhances the condensation heat transfer coefficient significantly compared with film condensation. In the present study, dropwise condensation heat transfer characteristics on titanium corrugated tubes were investigated. Two corrugated tubes with different corrugation pitch and depth were tested at the steam pressures of 5 and 10[Formula: see text]kPa. To promote dropwise condensation, silane-based SAM was coated. For bare corrugated tubes, significant enhancement of condensation heat transfer was noted, especially for the 2.1/0.2 (corrugation pitch/corrugation depth in mm) tube. For SAM-coated tubes, the heat transfer enhancement was significant (2.61 at 5[Formula: see text]kPa and 2.45 at 10[Formula: see text]kPa) for the smooth tube. For the corrugated tubes, however, the enhancement decreased to 1.78 and 2.22 for 8.7/0.4 tube and to 1.26 and 1.52 for 2.1/0.2 tube. The present results suggest that corrugations may not be as an effective heat transfer method for dropwise condensation as it is for film condensation. This result was supported by the photos taken by mist spray, which suggested that surface tension drained condensation by corrugations is not a major heat transfer mechanism for dropwise condensation on corrugated tubes.

Regioselective reaction of N-trimethylsilyl-N-acetylglycine N’,N’-dimethylamide with chloro(chloromethyl)dimethylsilane yields chlorosilane MeC(O)N(CH2SiMe2Cl)CH2C(O)NMe2 with a five-membered C,O-chelate ring involving the N-acetyl group rather than the six-membered ring involving the N’,N’-dimethylamide fragment. According to X-ray data, the pentacoordinate silicon atom in the product has a TBP environment with the halogen and oxygen atoms in axial positions.

Hydrophobic silica coating on copper (Cu) has been successfully prepared byelectrophoretic deposition (EPD) of silica sol prepared from waterglass. trimethyl chlorosilane (TMCS) was used as the modifying agent to produce hydrophobic coating by replacing the silanol groups on the silica surface with alkyl groups. The hydrophobicity was indicated by the contact angle of water droplet on the coating surface. It has been shown that TMCS concentration plays an important role in the preparation of hydrophobic coating. However, higher concentration of TMCS made the copper corroded before coated with silica due to the production of Cl-ions when TMCS reacted with water and silanol groups during electrophoretic deposition. In addition, the electricfield intensity, silica concentration and deposition time also influence the hydrophobicity of the coating. Increasing the three parameters produces silica coating with higher hydrophobicity. Thecontact angle of the silica coating can reach 130°. EIS analysis showed that the silica coating is very porous.

A bit borane: Silicon-functionalized dibenzosilaborins were prepared by intramolecular B-H/C-H dehydrogenative cyclization of o-(silyl)(hydroboryl)benzenes. The hydrosilyl derivative (X=H) can be converted into the fluorosilane (X=F) and chlorosilane (X=Cl). UV/Vis and fluorescence spectra are influenced by the functional groups X on the silicon atom through σ*-π* conjugation.

2-Aminopyridinyl iron(III) complex was grafted on chlorosilane modified mesoporous MCM-41 to give MCM-Py-Fe(III). The immobilization was confirmed by FT-IR, 13C, 29Si, 15N CP/MAS NMR, nitrogen adsorption–desorption study and elemental analysis. The powder XRD and TEM microscopy studies of the hybrid material confirmed the retention of the well-ordered honeycomb hexagonal structure in MCM-Py-Fe(III). The specific surface area of MCM-Py-Fe(III) was found to be 455 m2 g−1 and it had a pore volume of 0.27 cm3 g−1 with an average pore diameter of 26.7 A. The 13C CP/MAS NMR of MCM-Py-Fe(III) showed chemical shifts in the range of 113–155 ppm, which was assigned to the aromatic carbons in the pyridine ring. The 15N CP/MAS NMR showed the presence of chemical shifts at 550, 426 and 401 ppm for the three nitrogen atoms in the catalyst.

The main problem of existing methyl chlorosilane separation process is high energy consumption and low products purity. Based on the column grand composite curve is established by Aspen Plus and combined with the process integration technology, a modification of the process is proposed to improve the energy efficiency. Compared with the original process, the total condense and reboiler duty decrease by 8.47%, 8.96% respectively.

The synthesis and structures of silaoxazolinium salts 2 and their application to the catalytic Mukaiyama aldol reaction are described. The reaction of (N-amidomethyl)dimethylchlorosilane (1a) or (N-amidomethyl)bis(trimethylsilyl)chlorosilane (1b) with metal salts of weakly coordinating anions such as Na[TFPB] (TFPB = B[3,5-(CF3)2C6H3]4–) and Cs[CB11H12] (CB11H12– = carba-closo-dodecaborate) gave the corresponding five-membered-ring silaoxazolinium salts 2 in high yields (93–97%). The structures of a series of silaoxazolinium salts 2 were determined by X-ray crystal analysis as well as 29Si NMR spectra. It was proved that the silicon atoms of silaoxazolinium salts 2a,b are nearly completely free from the coordination of anions, and the geometries of the silicon centers are distorted tetrahedra. The 29Si chemical shifts of salts 2 appeared in the range +31 to +49 ppm, revealing the appreciable silylium cation character of the silicon. The silaoxazolinium salt of TFPB anion 2a exhibited effective catalytic a...

Dimethyldichlorosilane (DMDCS), diethyldichlorosilane (DEDCS), and dibutyldichlorosilane (DBDCS) were dissolved in supercritical CO2 at two concentration levels to modify hydrolyzed porous surfaces via silylation reactions. Plasma-damaged methylsilsesquioxane samples were loaded in a batch reactor with the chlorosilanes; when introduced, the low-viscosity supercritical CO2 dissolved and transported the chlorosilanes to the porous surface. Samples were characterized using Fourier transform infrared spectroscopy (FTIR), ellipsometry, goniometry, and electrical measurements, and compared against untreated samples. Reactions between the chlorosilanes and substrate hydroxyls were strongly dependent on the length of the alkyl group on the chlorosilane, but independent of concentration. FTIR analyses showed a decreased intensity for infrared (IR)-isolated/geminal OH vibrations (100%, 93.9% ± 5.4%, and 95.4% ± 4.3% for DMDCS, DEDCS, and DBDCS, respectively), but DEDCS and DBDCS resulted in 3.9% ± 5.0% and 20.9% ±...

The synthesis, characterization, and self-assembly of a range of ABC star polymers with arms of polyisoprene, poly(ferrocenylethylmethylsilane), and polystyrene is reported. A library of azide-functionalized polyisoprene and poly(ferrocenylethylmethylsilane) homopolymers were prepared by living anionic polymerization. Polystyrene was synthesized by living anionic polymerization and quenched with 3-triisopropylsilylethynyl-5-trimethylsilylethynylbenzaldehyde, yielding “core-functionalized” polystyrene with two different alkyne units. The azide-functionalized monomers were sequentially attached to core-functionalized polystyrene via copper(I)-catalyzed azide–alkyne cycloaddition reactions, giving polystyrene–polyisoprene–poly(ferrocenylethylmethylsilane) ABC star terpolymers with different compositions and narrow dispersities. Additionally, a chlorosilane route was employed as an alternative means of synthesis. Bulk films of each star terpolymer were prepared, and their self-assembly was analyzed by transmi...

The objective of this work is to investigate the relationship between sulfur adsorption capacity and surface acidity of supported silver oxide adsorbents from liquid hydrocarbon fuels. Inherently acidic supports such as TiO 2 and Al 2 O 3 developed sulfur adsorption capacity following activation in air at temperatures above 350 °C. Addition of Ag to these supports further increased sulfur adsorption capacity by ∼40%. Efforts were made to understand the thermal activation process and the sulfur adsorption mechanism. Breakthrough characteristics of various hetero aromatic molecules revealed that the strengths of adsorption increased with electronegativities of the heteroatoms. Sulfur adsorption capacities of these adsorbents were progressively reduced when poisoned with increasingly basic molecules. Surface acidity was measured using NH 3 chemisorption and titration with 2,6-lutidine. Interactions of probe molecules on acid centers were also observed from IR spectroscopy where both Bronsted and Lewis centers were observed. However interactions with 2,6-lutidine and trimethyl chlorosilane indicated that the active centers involved in sulfur adsorption were primarily Bronsted in nature. A clear correlation between activation temperature, surface acidity, and sulfur adsorption capacity was established for both blank and Ag loaded samples.

The potential application of palladium-ruthenium composite membranes to the separation of hydrogen from chlorosilane gases in silicon-based industries was investigated. Palladium and palladium-ruthenium composite membranes were deposited on pretreated porous stainless steel substrates by electroless plating. Hydrogen permeation tests and temperature programmed desorption (TPD) analysis revealed that the addition of a Ru overlayer on Pd changed the hydrogen adsorption characteristics, resulting in improved stability of the membrane at low temperatures. The Ru/Pd/Al 2 O 3 /PSS composite membrane had a stable hydrogen permeation flux of 1.8 m 3 m −2 h −1 over a period of 1200 h at 180 °C without suffering hydrogen embrittlement. After exposure to impurities such as HCl and SiHCl 3 , the hydrogen permeation flux of the Ru/Pd/Al 2 O 3 /PSS composite membrane was stable over a period of 9 h with feed pressure of 2.0 bar at 225 °C. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and EDX mapping of the Ru/Pd/Al 2 O 3 /PSS membrane after the exposure test showed no surface deposition of Si and Cl.

Core–shell CdSe/ZnS quantum dots (QDs) are useful as tunable photostable fluorophores for multiple applications in industry, biology, and medicine. However, to achieve the optimum optical properties, the surface of the QDs must be passivated to remove charged sites that might bind extraneous substances and allow aggregation. Here we describe a method of growing an organic polymer corona onto the QD surface using the bottom-up approach of surface-initiated ring-opening metathesis polymerization (SI-ROMP) with Grubbs catalyst. CdSe/ZnS QDs were first coated with mercaptopropionic acid by displacing the original tri-octylphosphine oxide layer, and then reacted with 7-octenyl dimethyl chlorosilane. The resulting octenyl double bonds allowed the attachment of ruthenium alkylidene groups as a catalyst. A subsequent metathesis reaction with strained bicyclic monomers (norbornene-dicarbonyl chloride (NDC), and a mixture of NDC and norbornenylethylisobutyl-polyhedral oligomeric silsesquioxane (norbornoPOSS)) allowed the construction of tethered organic homo-polymer or co-polymer layers onto the QD. Compounds were characterized by FT-IR, 1H-NMR, X-ray photoelectron spectroscopy, differential scanning calorimetry, and transmission electron microscopy. Atomic force microscopy showed that the coated QDs were separate and non-aggregated with a range of diameter of 48–53 nm.

A new PFCP-based chlorosilane monomer containing a latent reactive fluorine atom was synthesized utilizing a hydrosilylation reaction. This monomer was used to functionalize Stöber silica nanoparticles, or network silicas, and the ability to tailor the properties of the functionalized nanoparticles was investigated by reacting the latent reactive fluorinated alkene with various nucleophiles. In order to model the chemical transformations occuring with the PFCP-functionalized particles, a new PFCP-containing molecular silica was prepared using a hydrosilylation reaction. The molecular silica was designed such that it contained a latent reactive fluorine atom and could also undergo post-synthetic modifications with various nucleophiles. The ability to modify the latent reactive group and tune the properties of the molecular and network silicas was verified by multi-nuclear NMR ((1)H, (13)C, (19)F, and (29)Si), thermal characterizations, and by investigating the hydrophobicity and surface morphology of spin-cast films prepared from the molecular and network silicas.

A facile and efficient method has been developed for the preparation of seven-membered heterocycles 1,5-benzoxazepines by MeSiCl3/DMF-catalyzed domino reaction via the addition of in situ generated enamines to aldehydes . The advantages of this method are that it operates easily and achieves good yields for a broad scope of aldehyde substrates. And the corresponding products can be readily transformed to other categories of compounds, such as the hydrogenated products , which may have potential application in drug industry.

We have studied the reduction of silicon tetrachloride in the presence of a nickel-chloride-based catalyst. The kinetics of the process have been analyzed and the order and activation energy of the reaction have been determined. One of the main reactions on the catalyst surface is the transfer of a chlorine atom from a chlorosilane molecule to a hydrogen molecule, resulting in the formation of hydrogen chloride. The proposed reaction mechanism is supported by X-ray diffraction and chemical analysis data.

A silica residue from waste treatment of chlorosilane production was used together with solid sodium aluminate to test its applicability for the production of one-part geopolymers. The blend was activated with water and cured at 70 °C. The degree of reaction and strength were determined after 1, 3, and 7 days. The reaction products were analyzed by XRD and SEM/EDX. Until the third day of curing the degree of reaction of the residue reached 51 % and the strength was 8.9 MPa. The reaction product was identified as geopolymer containing zeolite A. Thus, the results confirmed that the residue may be used in the production of geopolymers. However, after 3 days of curing no further progress of reaction was observed and the strength slightly decreased, which was attributed to changes in the structure of the geopolymeric gel. It was further observed that even harsh vacuum drying left some water (presumably zeolitic water and surface hydroxyl groups) in the geopolymer.

An effective method was proposed to recycle trimethyl chlorosilane (Me3SiCl) from chlorosilane waste generated by chlorosilane plants to produce hexamethyldisiloxane (Me3SiOSiMe3) and trimethylethoxysilane (Me3SiOEt) through hydrolysis and alcoholysis with ethanol, respectively. And this method had been used successfully in a chemical plant of Hebei Hongxing in North China. The concentration of Me3SiCl in the waste stream varied between 40 wt%~80 wt% mixed with SiCl4, Me2SiCl2, and a smaller amount of 2-MeC5H11 and 3-MeC5H11. Laboratory experiments were performed using simulated wastes in order to obtain optimal operational parameters and validate the feasibility of the method.

This investigation focused on the synthesis and characterization of a modified polyvinylsilazane (PVSZ) polymer. Previously, our group synthesized the PVSZ polymer through the ammonolysis of vinyltrichlorosilane (VTS) in tetrahydrofuran (THF). This material showed promise as a precursor for silicon nitride–silicon carbide-based ceramic materials. Due to the structure of the PVSZ polymer, the ability to stabilize (shelf-life) and dope with metals and metalloids has proven to be difficult. To overcome these problems, a second chlorosilane precursor, dichloromethylsilane, was introduced into the ammonolysis reaction. This polymer proved to be more stable (>3 months before cross-linking) and added a potential doping site on the backbone of the polymer while maintaining ceramic yields greater than 80%. The polymethylvinylsilazane (PMVSZ) polymer was characterized using attenuated total reflectance (ATR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and elemental analysis. The results indicated that the ratio of chlorosilane precursors used plays an important role in the composition of crystallized ceramic material.

Under microwave radiation and using trimethyl chlorosilane as modifier, hydrophobic SiO2 aerogel was prepared through fractional hydrophobic modification and ambient pressure drying of the raw material, tetraethoxysilane (TEOS), in the process of sol-gel and acid-base catalysis. Hydrophilic SiO2 aerogels were also prepared using the microwave method and water bath heating method. The SiO2 aerogels prepared using the three methods, including their morphology and chemical composition, were analyzed and compared using scanning electron microscopy, Brunauer-Emmett-Teller analysis method, Fourier transform infrared spectroscopy, X-ray diffraction, and themogravimetric-differential scanning calorimetry. The results indicate that by adopting the microwave reaction, the specific surface area of the SiO2 aerogels was effectively increased and the structure of the internal nanoscale pores of petal-coated shape was found to exist under the dense external surface of the SiO2 aerogels. Thermal stability of the hydrophobic SiO2 aerogels prepared through fractional modification assisted by the microwave method was increased with the hydrophobic angle at153°, which showed super hydrophobicity.

Core–shell structures of zeolite X coated with silicalite as well as mesoporous (MCM-41) have been synthesized. Furthermore, the surfaces of the silicalite and mesoporous silica shells were silylated using organosilanes. The materials were characterized by X-ray diffraction, nitrogen adsorption/desorption, scanning and transmission electron microscopy. The results show that the properties of zeolite 13X@silicalite and zeolite 13X@mesoporous silica core–shells composite structures are well maintained even after the modification. As expected, the shell thickness increased with increase in synthesis time, however, the micropore volume decreased. Silylation with smaller organosilanes (trimethyl chlorosilane) resulted in decrease in surface area as they diffused through the pores; however, bulkier silane reacted with surface hydroxyl groups and maintained the pore structure. Contact angle measurements revealed that hydrophobicity of zeolite 13X was enhanced by the microporous and mesoporous shell coating and was further improved by silylation.

Mesoporous material of MCM-41 type has been modified by the introduction of aluminium and copper, and then by grafting with trimethyl chlorosilane (TMCS). The influence of these treatments on the mesoporous materials was evaluated by the reaction of phenol degradation in the presence of H 2 O 2 . The characterization of the materials by several techniques (X-ray diffraction, N2 adsorption, UV and IRTF spectroscopies, etc.) shows that the mesostructural order is retained after the different modifications and that the grafting enhances the catalytic activity in the degradation of phenol.

A novel molecularly imprinted polymer (MIP)-modified quartz crystal microbalance (QCM) sensor with high selectivity has been developed for the determination of folic acid via activator generated-atom transfer radical polymerization (AGET-ATRP) technique. It requires an alkyl halide (R-X) as an initiator, a transition metal complex as a catalyst, and an amine as reducing agent. Herein, chlorosilane was used as initiator which was grafted onto the self assembled monolayer modified-quartz crystal surface followed by the addition of pre-polymer mixture which latter underwent thermal cross-linking resulting in MIP-modified QCM sensor. The linear working range (quantification) was found to be 0.6-26.0 μg L -1 , with the detection limit as low as 0.08 μg L -1 (S/N=3). Copyright © 2011 VBRI press.

The synthesis of well-defined multigraft copolymers having a polydiene backbone with polystyrene side chains is briefly reviewed, with particular focus on controlling branch point spacing and branch point functionality. Use of living anionic polymerization and chlorosilane linking chemistry has led to the synthesis of series of materials having regularly spaced trifunctional (comb), tetrafunctional (centipede), and hexafunctional (barbwire) branch points. The morphologies of these materials were characterized by transmission electron microscopy and small-angle X-ray scattering, and it was found that the morphologies were controlled by the local architectural asymmetry associated with each branch point. Mechanical properties studies revealed that such multigraft copolymers represent a new class of thermoplastic elastomers (TPEs) with superior elongation at break and low residual strains as compared to conventional TPEs.

An incompletely condensed silsesquioxane containing trisilanol ( c -C 5 H 9 ) 7 Si 7 O 9 (OH) 3 reacts with [PdI 2 (bpy)] (bpy = 2,2′-bipyridine) in the presence of Ag 2 O to produce a palladium complex with an O , O -chelating silsesquioxanate ligand, [Pd{O 11 Si 7 ( c -C 5 H 9 ) 7 (OH)}(bpy)] ( 1 ). The reaction of Ph 2 SiClH with 1 in 2:1 ratio causes disilylations of the silsesquioxanate ligand, forming [PdCl 2 (bpy)]. Addition of p -cresol to a solution of 1 yields the trisilanol and [Pd(OC 6 H 4 CH 3 - p ) 2 (bpy)].

A new material has been synthesized using dry process to activate bentonite followed by N -(2-hydroxyethyl) ethylenediamine connecting chlorosilane coupling agent. The synthesized new material was characterized by elemental analysis, FT-IR and thermogravimetry which proved that bentonite was successfully modified. The most interesting trait of the new material was its selective adsorption for rare earth elements. A variety of conditions of the new material were investigated for adsorption. The optimal conditions were determined with respect to pH and shaking time. Samarium (Sm) was quantitatively adsorbed at pH 4 and shaking time of 2 min onto the new material. Under these conditions the maximum static adsorption capacity of Sm(III) was found to be 17.7 mg g −1 . The adsorbed Sm(III) ion were quantitatively eluted by 2.0 mL 0.1 mol L −1 HCl and 5% CS (NH 2 ) 2 solution. According to IUPAC definition, the detection limit (3 σ ) of this method was 0.60 ng mL −1 . The relative standard deviation (RSD) under optimum conditions was less than 3% ( n = 8). The new material also was applied for the preconcentration of trace Sm(III) in environmental samples with satisfactory results.

PVDF was blended with PVC to improve the weldable property of PVDF topcoat. Effects of film formation process on the surface properties of PVDF/PVC blended film were investigated. Peeling strength of PVDF/PVC blended film has reached the internationally accepted standards (144.3N/5cm) when PVC concentration was 30%. Based on the “lotus effect” principle, PVDF/PVC film was hydrophilic modified by alkali solution and then grafted with alkyl chlorosilane to fabricate the micro- and nano-structures as the surface of lotus leaf. After grafting, contact angle of PVDF/PVC blended film was as high as 152.8°, and self-cleaning test showed dusts on this film surface can be easily taken away by water droplet when PVDF/PVC blended film was titled less than 1°.

The sol-gel method was chosen in the experiment to make nano-structured coatings on the ceramics. In this experiment the TEOS, ETOH were chosen as the main reagents and the two group formulas whose scale were 3:50 and 18:25 were chosen to make the sol of silica by the way of sol-gel, and the two formula were mixed on some scale. The sols of the three formulas would be spread on the ceramics separately; and then burned in different temperatures of 500°C, 800°C, 900°C and 1000°C, last the samples were put into the 10% of trim ethyl chlorosilane of n-hexane solution to adorn the surface of spread the gel ceramics. The result of the samples, which are uncalcined, calcined and black and calcined and the surface adorned compared, shows that the contact angle of samples that have been calcined and the surface adorned becomes bigger. So the hydrophic effect is the best when there are all of the microstructure and the low-surface power on the ceramics surface.