Friedel-Crafts Alkylation of Resorcinol over Mesoporous Alumina Loaded with Sulfuric Acid

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Sheela Chandren ◽  
Zainab Ramli ◽  
Hadi Nur
Keyword(s):  
Sulfuric Acid ◽  
Sol Gel ◽  
Mesoporous Alumina ◽  
Lewis Acidity ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Gel Method ◽  
Sol Gel Method ◽  
Tert Butyl ◽  
Brönsted Acidity

Mesoporous alumina which contains only Lewis acidity was synthesized by sol-gel method and was then impregnated with sulfuric acid to generate Brönsted acidity. The catalyst was used in Friedel-Crafts alkylation of resorcinol with methyl tert-butyl ether to produce 4-tert-butylresorcinol and 4,6-di-tert-butylresor- cinol as the major and minor products respectively. It was demonstrated that Lewis and Brönsted acidities play a synergetic role in this reaction.

scholarly journals Reactivity and Reusability of Mesoporous Alumina Nanoparticles Modified with Sulfuric Acid and Niobic Acid in the Alkylation of Resorcinol

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Zainab Ramli ◽  
Hadi Nur ◽  
Sheela Chandren
Keyword(s):  
Sulfuric Acid ◽  
High Surface ◽  
Mesoporous Alumina ◽  
Alumina Nanoparticles ◽  
Lewis Acidity ◽  
Methyl Tert Butyl Ether ◽  
Solid Catalyst ◽  
Brønsted Acidity ◽  
Brönsted Acidity ◽  
Niobic Acid

With the development of large molecule hydrocarbon processes, mesoporous alumina which possesses high surface area with narrow pore size distribution has received a great deal of attention. However, its acid properties lack Bronsted acidity and showed only Lewis acid sites, making it an inactive solid catalyst in the alkylation of resorcinol, a reaction which requires the usage of solid acid catalysts with both Bronsted and Lewis acidity. In this study, in order to introduce Bronsted acidity to mesoporous alumina, sulfuric acid (H2SO4) and niobic acid (Nb2O5.nH2O) are introduced to the alumina. The reactivity of mesoporous alumina nanoparticles (MAN), Nb2O5.nH2O/MAN and H2SO4/MAN were tested out on the alkylation of resorcinol with methyl tert-butyl ether. No product was obtained using pure MAN, while both H2SO4/MAN and Nb2O5.nH2O/MAN managed to produce butylated resorcinol. Mesoporous alumina nanoparticles incorporated with sulfuric acid produced a greater amount of dibutylated resorcinol, which theoretically is a better antioxidant compared to monobutylated resorcinol. The reusability of the H2SO4/MAN catalyst was also better as dibutylated product was still obtained even in the second use. This indicates that sulfuric acid has created a more stable and also higher strength of Bronsted acidity in alumina as compared to niobic acid.

Preparation of novel uniform mesoporous alumina catalysts by the sol–gel method

2001 ◽  
Vol 68 (1-3) ◽  
pp. 97-109 ◽  
Author(s):  
Nan Yao ◽  
Guoxing Xiong ◽  
Yuhong Zhang ◽  
Mingyuan He ◽  
Weishen Yang
Keyword(s):  
Sol Gel ◽  
Mesoporous Alumina ◽  
Gel Method ◽  
Sol Gel Method ◽  
Alumina Catalysts

Effect of p-aminobenzoic acid on synthesizing ordered mesoporous alumina via the sol–gel method

2014 ◽  
Vol 21 (5) ◽  
pp. 819-825 ◽  
Author(s):  
Xue-Lin Zheng ◽  
Qian-Ping Sun ◽  
Fang Liu ◽  
Ying Zheng ◽  
Jia-Bao Weng
Keyword(s):  
Sol Gel ◽  
Mesoporous Alumina ◽  
Aminobenzoic Acid ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ordered Mesoporous ◽  
Ordered Mesoporous Alumina

Synthesis of Silica Gel and Development of Coating Method for Applications in a Regenerative Air Dehumidifier

2016 ◽  
Vol 839 ◽  
pp. 70-74
Author(s):  
Winit Aimjaijit ◽  
Pipat Chaiwiwatworakul ◽  
Surawut Chuangchote
Keyword(s):  
Sulfuric Acid ◽  
Heat Exchanger ◽  
Surface Area ◽  
Silica Gel ◽  
Sol Gel ◽  
Dip Coating ◽  
Moisture Adsorption ◽  
Air Conditioners ◽  
Gel Method ◽  
Sol Gel Method

In order to control humidity in air conditioning system, various desiccants are used to dehumidify air in air conditioners. One of simple methods, which can be used to coat desiccant materials on surface of heat exchanger in air conditioners, is dip coating. Typical, desiccants used in dehumidifying system is silica gel in a form of solid-state powder. This powder has low adhesion with the heat exchanger surface. To improve adhesion of the silica gel powder, some glue is generally applied on the surface of heat exchanger. The dehumidification properties of silica gel, however, will be remarkably reduced because of less surface area of silica gel powder. Instead of silica powder, this work aims to synthesize silica gel using sol-gel method, which the sol-state material can be suitably used in dip coating. In experimental study, silica gel was synthesized by sol-gel method of precursors with 1 M sulfuric acid (H2SO4). The pH was adjusted using sodium silicate solution (Na2O(SiO2)x.xH2O) and rinsing with DI water. Surface area, pore volume and size, phase composition, morphology, and percentage of moisture adsorption of the synthesized silica gel were characterized. Silica gel fabricated with pH 5 showed the highest percentage of moisture adsorption compared with other samples. In addition to the highest percentage, silica gel with pH 5 could adsorb water up to 28 times of its own weight. X-ray diffraction (XRD) results showed that Na2SO4 impurity were successfully eliminated after rinsing with DI water more than 4 times. Finally, adhesive property of silica gel on aluminium-fin samples was tested with scalloped tape-test method. It was observed that, to improve the adhesion property of silica gel on the aluminium fins, prior to dipping of silica gel, the fins should be etched with sulfuric acid. The acid can adjust the surface of fines to be much rougher.

scholarly journals Pore surface fractal analysis of PEG and La(III)-doped mesoporous alumina obtained by the sol-gel method

2010 ◽  
Vol 75 (6) ◽  
pp. 833-843 ◽  
Author(s):  
Tatjana Novakovic ◽  
Ljiljana Rozic ◽  
Srdjan Petrovic ◽  
Zorica Vukovic ◽  
Vera Dondur
Keyword(s):  
Fractal Analysis ◽  
Sol Gel ◽  
Mesoporous Alumina ◽  
Chemical Compositions ◽  
Pore Surface ◽  
Heterogeneous Distribution ◽  
Gel Method ◽  
Sol Gel Method ◽  
Surface Fractal ◽  
D Value

Active porous alumina was prepared via a sol-gel method and subjected to thermal treatment in the temperature range 500-1200 ?C. The addition of lanthanum effectively inhibited the surface area loss of the aluminas. Fractal analysis from nitrogen adsorption isotherm was used to study the pore surface roughness of alumina samples with different chemical compositions (PEG, PEG and lanthanum) and calcinations conditions in terms of the surface fractal dimension, d. The Mahnke and M?gel (MM) model was used to determine the value of d of La(III)-doped alumina. Following the MM model, the d value of the activated aluminas increased as the calcination temperature increased from 500 to 700 ?C but decreased after calcination at 1000, 1100 and 1200 ?C. The addition of polyethylene glycol (PEG 5600) to the boehmite sol reduced the surface fractal of the activated alumina due to the heterogeneous distribution of the pores. With increasing La(III) concentration from 0.015 to 0.045 mol La(III)/mol Al(III), the d value of La-modified alumina samples decreased, indicating a smoother surface. The obtained PEG+La-doped boehmite sol can be used as a precursor dispersion for the deposition of mesoporous alumina coatings on stainless steel foil, by the spray pyrrolysis method.

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