نتایج جستجو برای: hexamethyldisilazane (hmds)

تعداد نتایج: 497  

Journal: :Chemical communications 2008
David R Armstrong William Clegg Sophie H Dale Joaquín García-Alvarez Ross W Harrington Eva Hevia Gordon W Honeyman Alan R Kennedy Robert E Mulvey Charles T O'Hara

In a new type of reactivity for sodium TMP-zincate [(TMEDA)NaZn((t)Bu)(2)(TMP)] (1), transamination reactions with the amines diisopropylamine, DA(H), hexamethyldisilazane, HMDS(H) and chiral (R)-N-benzyl-alpha-methylbenzylamine have produced new sodium amido-di-tert-butyl zincates (all structurally characterised) with concomitant loss of TMP(H).

Trimethylsilylation of a variety of alcohols and phenols, in the presence of silica chloride, using hexamethyldisilazane (HMDS) in solution and under solvent-free conditions is reported. Trimethylsilyl ethers were formed in excellent yields both for aliphatic alcohols and phenols without having an electron-withdrawing group. In addition, SiO2-Cl can be recovered and reused after drying.

Journal: :journal of sciences islamic republic of iran 0

trimethylsilylation of a variety of alcohols and phenols, in the presence of silica chloride, using hexamethyldisilazane (hmds) in solution and under solvent-free conditions is reported. trimethylsilyl ethers were formed in excellent yields both for aliphatic alcohols and phenols without having an electron-withdrawing group. in addition, sio2-cl can be recovered and reused after drying.

Journal: :Dental materials : official publication of the Academy of Dental Materials 2009
Elsa Vennat Christine Bogicevic Jean-Marie Fleureau Michel Degrange

OBJECTIVES The objectives of this study were to assess demineralized dentin porosity and quantify the different porous features distribution within the material using mercury intrusion porosimetry (MIP) technique. We compared hexamethyldisilazane (HMDS) drying and lyophilization (LYO) (freeze-drying) in sample preparation. METHODS Fifty-six dentin discs were assigned into three groups. The co...

Journal: :Journal of Physics: Conference Series 2021

Abstract The analysis of composition low-pressure (~0.1-1 mTorr) hollow cathode arc plasma in Ar+N2 gas mixture with Ti+hexamethyldisilazane vapors was carried out by optical emission spectroscopy. influence HMDS flow rate (1-10 g/h), discharge current (10-50 A) and Ti-vapors on hexamethyldisilazane decomposition degree investigated. proposed activation method provides both an intense a high me...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2006
R Nageswara Rao S Meena D Nagaraju A Raghuram Rao S Ravikanth

A simple and rapid reversed-phase high-performance liquid-chromatographic method for the separation and determination of process-related impurities of celecoxib (CXB) in bulk drugs and pharmaceuticals was developed. The separation of impurities viz., 4-methylacetophenone (I), 1-(4-methylphenyl)-4,4,4-trifluorobutane-1,3-dione (II), 4-hydrazinobenzene sulfonamide (III) and a regio-specific isome...

Trimethylsilylation of alcohols and phenols were carried out under solvent-free conditions with hexamethyldisilazane (HMDS) using LaCoO3 perovskite. LaCoO3 as an efficient catalyst accelerated this reaction under milder condition. The advantages of this method are evident regarding, easy separation, low cost and low catalyst loading, lack of pollution, easy work-up, and selective protection of ...

2011
Nevin Tasaltin Deniz Sanli Alexandr Jonáš Alper Kiraz Can Erkey

Superhydrophobic nanoporous anodic aluminum oxide (alumina) surfaces were prepared using treatment with vapor-phase hexamethyldisilazane (HMDS). Nanoporous alumina substrates were first made using a two-step anodization process. Subsequently, a repeated modification procedure was employed for efficient incorporation of the terminal methyl groups of HMDS to the alumina surface. Morphology of the...

2014
Yessi Jusman Siew Cheok Ng Noor Azuan Abu Osman

This paper investigated the effects of critical-point drying (CPD) and hexamethyldisilazane (HMDS) sample preparation techniques for cervical cells on field emission scanning electron microscopy and energy dispersive X-ray (FE-SEM/EDX). We investigated the visualization of cervical cell image and elemental distribution on the cervical cell for two techniques of sample preparation. Using FE-SEM/...

Journal: :iranian journal of catalysis 2013
hassan tajik khodabakhsh niknam somayeh karimian

in this research, different alcohols and phenols are subjected to the reaction with hmds in the presence of ionic liquid and silica-supported catalysts. silylation was accomplished under mild reaction conditions at room temperature in short reaction times and good to excellent yields.

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