Effect of malic acid on structure of silicon alkoxide derived silica

Izutsu, Hiroyuki; Mizukami, Fujio; Sashida, Takeshi; Maeda, Kazuyuki; Kiyozumi, Yoshimichi; Akiyama, Yoshikatsu

doi:10.1016/s0022-3093(96)00620-5

Cited by 49 publications

(24 citation statements)

References 33 publications

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“…The solid catalysts are a mass of objects for study of the sol-gel method. In recent years, much attention has been focused on the preparation of mesoporous materials [2][3][4][5][6][7][8][9][10], specifically the composite catalysts including micro/mesoporous materials for various reactions [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Zeolite has the high surface area and many strong acid sites, which give a potential for the high adsorption ability or the high activity in the reactions.…”

Section: Introductionmentioning

confidence: 99%

Preparation of hierarchical β and Y zeolite-containing mesoporous silica–aluminas and their properties for catalytic cracking of n-dodecane

Ishihara

Inui

Hashimoto

et al. 2012

Journal of Catalysis

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Section: Introductionmentioning

confidence: 99%

Preparation of hierarchical β and Y zeolite-containing mesoporous silica–aluminas and their properties for catalytic cracking of n-dodecane

Ishihara

Inui

Hashimoto

et al. 2012

Journal of Catalysis

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“…The solgel process is one of the promising methods and the control of the processes of hydrolysis and condensation is a key to obtain the desired pore structure with the good reproducibility [1]. One method to control these processes is to produce a metal complex using a ligand which can coordinate with a metal ion [2,3]. These ligands remain in the inside of the gel formed and change the extent and rate of polymerization, and their size itself also changes the size and diameter of pores formed [4].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Amorphous Silica-Alumina Using the Sol–Gel Method and its Reactivity for a Matrix in Catalytic Cracking

Ishihara

2012

Catal Surv Asia

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Amorphous silica-aluminas were prepared by the sol-gel method using organic templates such as carboxylic acid and the gel skeletal reinforcement method. Their reactivities as a matrix for the catalytic cracking were investigated. Malic acid (MA) was used as a catalyst for the sol-gel method, an organic template and a reagent for the dispersion of Al. When the ratio of MA/TEOS (tetraethoxysilane) increased from 0.22 to 1.22, surface area, pore volume and pore diameter increased and the mesopore was formed at 1.22. Their average BET pore diameters for 0.22 and 1.22 of MA/TEOS were 2.0 to 5.1 nm, respectively. Although conversions of n-dodecane were around 20% or less with single amorphous silica-aluminas, both single beta-zeolite and the mixed catalysts of zeolite and amorphous silica-aluminas showed much higher activity. Further, the mixed catalyst using silica-alumina with mesopore (MAT(MA122-5)) exhibited the higher ratio of multi-branched paraffin to single branched paraffin in the gasoline franction of products (C5-C11) than the mixed catalysts using silica-alumina with only micropore and silica with mesopore or single zeolite. In the gel skeletal reinforcement method, tetraethoxy orthosilicate (TEOS) was used as not only a precursor of silica but also an agent which reinforces the skeleton of silica-gel to prepare an aerogel and extremely large mesopores were formed for resultant silicas and silica-aluminas. When silica aerogel was reinforced by TEOS solution, the pore diameter and pore volume reached 30 nm and 3.1 cm 3 /g, respectively, in the N 2 adsorption measurement by the BJH method, indicating that most of pores for this silica consisted of mesopores. In catalytic clacking reaction of n-dodecane, the mixed catalyst prepared by beta-zeolite and silica-alumina with large mesopore exhibited not only the comparable activity to that for single zeolite but also the unique selectivity where large amounts of branched products were formed. When the catalyst beds of silica-alumina and zeolite were separated, the reference silica-alumina (ref.SA) ? zeolite system exhibited the higher activity and the product selectivity close to those for MAT(ref.SA). It is likely that the primary cracking of n-dodecane on silica-alumina would occur to produce the primary cracked product which effectively reacted with zeolite and inhibited the coke formation by overcracking.

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“…Meanwhile, the role of hydrogen bonds formed between the acid groups of organic acids or hy droxy groups of glucose and growing inorganic macromol ecules was stressed. [17][18][19][20] If ionol, i.e., compound in which the hydroxy group is sterically protected by bulky substituents from the interac tion with the hydroxy groups of inorganic oligomer, is added during the sol-gel process, turbid films are formed instead of antireflecting coatings. This indicates that spon taneous macro rather than microseparation of phases oc curs at the first stage of the EISA process.…”

Section: Resultsmentioning

confidence: 99%

“…17, 18 It was shown that hydrolysis of tetraethoxy silane (TEOS) in the presence of 2 hydroxy 1,4 butane dicarboxylic acid, 2,3 dihydroxy 1,4 butanedicarboxylic acid in a dioxane solution afforded xerogels as powders with the pore size 4.5 nm. Analogous results were obtained with glucose and citric acid.…”

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confidence: 99%

To the problem of self-assembly of mixtures of inorganic and organic phases under the sol-gel process conditions

et al. 2008

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Under the sol-gel process conditions in the presence of citric, maleic, and phthalic acids and dioctyl phthalate spontaneous microseparation of inorganic and organic phases with the formation of transparent in the visible spectral region film coatings on glass is observed. The modified EISA method was proposed for the preparation of antireflecting coatings based on nanoporous silica with the low refractive index (1.27-1.33).Key words: sol-gel process, self assembly of mixtures of inorganic and organic phases, mesoporous materials, silica, antireflecting coatings.The method for production of the mesoporous material with a pore size of 2-4 nm has been described previously. 1 The method is based on the interaction of layered polysili cate kanemite (NaHSi 2 O 5 •3H 2 O) with alkyltrimethylam monium chloride (cation active surfactant). The cation exchange reaction affords a kanemite-surfactant com plex. After the complex was heated to 700 °С in air, the surfactant thermally decomposes to form the mesoporous material with a specific surface of 900 m 2 g -1 .Then the matrix synthesis of mesoporous silicates and aluminosilicates was discovered. 2-6 The group of meso porous materials M41S (MCM 41 is hexagonal me sophase, MCM 48 is cubic mesophase, and MCM 50 is lamellar mesophase) with a well developed uniform sys tem of nanosized structures was obtained 2-6 by the solgel process in the presence of the cation active surfactant. The efforts in this field increased rapidly due to the relative feasibility of the synthesis of new mesoporous materials and wide possibilities of their practical use in catalysis, microelectronics, optics, and as sensors. 7-16 Noniono genic and high molecular weight surfactants (amphiphilic binary and ternary block copolymers) were involved in the matrix synthesis of mesoporous materials. Mesopo rous xerogels based on both silica and other oxides were synthesized.In addition to two above methods of matrix synthesis of mesoporous materials, 1-16 the sol-gel synthesis of me soporous metal oxides was described using substances that are neither surfactants, nor amphiphilic block copoly mers. 17,18 It was shown that hydrolysis of tetraethoxy silane (TEOS) in the presence of 2 hydroxy 1,4 butane dicarboxylic acid, 2,3 dihydroxy 1,4 butanedicarboxylic acid in a dioxane solution afforded xerogels as powders with the pore size 4.5 nm. Analogous results were obtained with glucose and citric acid. 19,20It seemed reasonable to use possibilities of the third synthesis method for the production of transparent thin (100-200 nm) films of nanoporous silica on silicate glass. These films with a low refractive index can serve as effi cient antireflecting coatings.New concepts on self assembly of mixtures of inorgan ic and organic phases under the sol-gel process condi tions are described in the present work.We used the method of film deposition on the support known as the evaporation induced self assembly (EISA) technique. The technique involves depositing a coating on an underlayer by a spin or dip coating from a d...

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Effect of malic acid on structure of silicon alkoxide derived silica

Cited by 49 publications

References 33 publications

Preparation of hierarchical β and Y zeolite-containing mesoporous silica–aluminas and their properties for catalytic cracking of n-dodecane

Preparation of hierarchical β and Y zeolite-containing mesoporous silica–aluminas and their properties for catalytic cracking of n-dodecane

Preparation of Amorphous Silica-Alumina Using the Sol–Gel Method and its Reactivity for a Matrix in Catalytic Cracking

To the problem of self-assembly of mixtures of inorganic and organic phases under the sol-gel process conditions

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