搜索结果: 1-15 共查到“化学 silica”相关记录27条 . 查询时间(0.066 秒)
Friedel-Crafts acylation of arenes with carboxylic acids using silica gel supported AlCl3
Acylation aluminium trichloride ketones silica gel
2010/10/19
Aromatic compounds react smoothly with carboxylic acids in the presence of silica gel supported aluminium trichloride to afford the corresponding ketones with high regioselectivity in high to excellen...
Sulfonic acid-functionalized silica: a remarkably efficient heterogeneous reusable catalyst for the one-pot synthesis of 1,4-dihydropyridines
1,4-Dihydropyridine b-dicarbonyl compounds solid acid SiO2-R-SO3H
2010/10/19
An efficient one-pot method for the synthesis of 1,4-dihydropyridines from b-dicarbonyl compounds, aldehyde, and ammonium acetate is reported using sulfonic acid-functionalized silica at 90 °C under s...
Silica supported polyphosphoric acid (PPA-SiO2): an efficient and reusable heterogeneous catalyst for the one-pot synthesis of a -amino phosphonates
a -Amino phosphonates PPA-SiO2 heterogeneous catalyst
2010/10/19
An efficient green protocol is described for the preparation of a -amino phosphonates, employing a one-pot three-component condensation reaction between aldehydes, amines, and trialkyl phosphites in t...
Direct reductive amination of carbonyl compounds using sodium borohydride-silica chloride
Reductive amination silica chloride sodium borohydride
2010/10/15
A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica chloride as an active, inexpensive, recoverable, and recyclable ca...
Enantiomeric Separation by Capillary Electrochromatography on a Sulfated Poly β-Cyclodextrin Modified Silica-based Monolith
Enantiomeric Separation Capillary Electrochromatography Sulfated Poly β-Cyclodextrin
2010/9/17
A sulfated poly β-cyclodextrin (SPCD) modified silica-based monolithic column was prepared for enantiomeric separation. First, 2-hydroxy-3-allyloxy-propyl-β-cyclodextrin (allyl-β-CD) was bonded onto a...
A Fast-Response pH Optode Based on a Fluoroionophore Immobilized to a Mesoporous Silica Thin Film
A Fast-Response pH Optode a Fluoroionophore Immobilized Mesoporous Silica Thin Film
2010/9/17
This paper describes the preparation and characterization of an optical pH-sensing device using a H+-responsive fluoroionophore based on boron-dipyrromethene, immobilized to a mesoporous silica thin f...
Structural Analysis of High-Silica Ferrierite with Different Structure-Directing Agents by Solid-State NMR and Ab Initio Calculations
Structural Analysis High-Silica Ferrierite Structure-Directing Agents Solid-State NMR Calculations
2010/9/19
The host-guest interaction in high-silica ferrierite (FER) with different structure-directing agents (SDA), pyridine and piperidine, was analyzed by solid-state 29Si NMR relaxation experiments and mol...
Simultaneous Determinations of Cr(VI) and Cr(III) by Ion-Exclusion/Cation-Exchange Chromatography with an Unmodified Silica-Gel Column
Cr(VI) Cr(III) Ion-Exclusion/Cation-Exchange Chromatography an Unmodified Silica-Gel Column
2010/9/19
In order to characterize the ion-exclusion and cation-exchange properties of an unmodified silica-gel column, the retention behaviors of Cr(VI) and Cr(III) ions were investigated using a Develosil 30-...
Solid-Phase Extractors Based on 8-Aminoquinoline and 2-Aminopyridine Covalently Bonded to Silica Gel for the Selective Separation and Determination of Calcium in Natural Water and Pharmaceutical Samples
Solid-Phase Extractors 8-Aminoquinoline 2-Aminopyridine Covalently Bonded Silica Gel the Selective Separation Calcium
2010/9/20
Two new silica-gel phases were produced directly via the chemical interaction of 3-chloropropyltrimethoxysilane modified silica gel with 8-aminoquioline, phase I and 2-aminopyridine, phase II under re...
Specific Extraction of Sialic-acid-containing Glycans and Glycopeptides Using Serotonin-bonded Silica
Sialic-acid-containing Glycans Glycopeptides Serotonin-bonded Silica
2010/9/17
Serotonin-bonded silica was developed for specific extraction of sialic-acid-containing glycans and glycopeptides. Serotonin, coupled by reductive amination with aldehyde silica particles via its eth...
Chemoselective Oxidation of Sulfides with Ammonium Nitrate and Silica Sulfu-ric Acid Catalyzed by KBr
sulfide sulfoxide chemoselectivity ammonium nitrate potassium bromide silica sulfuric acid
2009/9/15
A convenient and selective catalytic method for the sulfoxidation of aliphatic and aromatic sulfides by treatment of NH4NO3, silica sulfuric acid, wet SiO2 (50% w/w) and a catalytic amount of KBr in C...
H2{SO}4-silica as an efficient and chemoselective catalyst for the synthesis of acylal from aldehydes under solvent-free conditions
Acylals aldehydes catalysis solvent-free reactions
2010/4/9
A variety of aldehydes react with acetic anhydride in the presence of a catalytic amount of H2SO4-silica to afford the corresponding 1,1-diacetates (acylals) in excellent yields. Ketones are not affec...
A novel way for preparing high surface area silica monolith with bimodal pore structure
A novel way preparing high surface area silica monolith bimodal pore structure
2013/12/12
The crack-free silica monolith with macropores and mesopores has successfully been achieved in the presence of citric acid as nonsurfactant via sol-gel reactions of tetramethoxysilane (TMOS). Citric a...
A Convenient and Efficient Synthesis of N-Acylsulfonamides in the Presence of Silica Phosphoric Acid under Heterogeneous and Solvent-Free Conditions
N-acylsulfonamide solvent-free silica phosphoric acid heterogeneous condition N-acylation
2010/4/8
Reaction of sulfonamides with carboxylic acid anhydrides and chlorides in the presence of silica phosphoric acid provided N-acyl sulfonamides in good to high yields. All reactions were performed under...
酞菁键合硅胶的制备及分离取代酞菁异构体（Preparation of Phthalocyanine Bonded Silica Gel for the Separation of Phthalocyanine Isomers）
酞菁键合硅胶 制备 分离 异构体
2010/8/18
制备和表征了一种新的酞菁键合硅胶，三-β-(辛巯基)-β-(磺酰胺基)-酞菁铜键合硅胶。研究了该键合酞菁硅胶作为HPLC固定相的基本色谱性能。实验结果表明，该固定相可以分离四-α-(2，2，4-三甲基-3-戊氧基)酞菁(铜、镍)的4种异构体，也可以观察到四-α-(2，2，4-三甲基-3-戊氧基)无金属酞菁的4种异构体，而商业C18(VERTEX Eurospher)却只能观察到两组峰，表明这种酞菁...