Properties of ZrO2, Gels Prepared by Controlled Chemical Modification Method of Alkoxide

1992 ◽  
Vol 271 ◽  
Author(s):  
Hisao Suzuki ◽  
Hajime Saito ◽  
Hiroaki Hayashl
Keyword(s):  
Acetic Acid ◽  
Chemical Modification ◽  
Condensation Reaction ◽  
Dip Coating ◽  
Butyl Alcohol ◽  
Mechanical Stirring ◽  
Polymeric Gels ◽  
Zirconium Alkoxide ◽  
Hydrolysis And Condensation ◽  
Modification Method

ABSTRACTPolymeric ZrO2 gels were prepared by the controlled chemical modification method (CCM method) of zirconium-n-propoxide. In this method, the steric hindrance by alkoxide-acetic acid chelation could be used to control the hydrolysis and condensation reaction of the zirconium alkoxide if the amount of hydrolysis water was limited. As a result, polycondensaticn occurred uniformly in the solution, forming a linear zirconoxane polymer. When the solvent evaporated, the zirconoxane polymer crosslinked with each other and formed polymeric ZrO2, gels, which were monolithic and transparent. These polymeric gels could be re-dissolved into n-butyl alcohol with acetic acid and mechanical stirring. Heating would enhance the dissolution of the gels. Using the re-dissolved gel solution, dense thin films of ZrO2, could be obtained by dip-coating procedures without many coating operations.

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

2020 ◽  
Author(s):  
Xue Yang ◽  
Yongling Liu ◽  
Tao Chen ◽  
Nana Wang ◽  
Hongmei Li ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Efficient Method ◽  
Crude Extract ◽  
High Speed ◽  
Glacial Acetic Acid ◽  
Butyl Alcohol ◽  
Preparative Hplc ◽  
Counter Current

Abstract Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

Single-layer submicron-thick BaTiO3 coatings from poly(vinylpyrrolidone)-containing sols: Gel-to-ceramic film conversion, densification, and dielectric properties

2001 ◽  
Vol 16 (11) ◽  
pp. 3116-3123 ◽  
Author(s):  
Hiromitsu Kozuka ◽  
Atsushi Higuchi
Keyword(s):  
Heat Treatment ◽  
Condensation Reaction ◽  
Single Layer ◽  
Dip Coating ◽  
Single Step ◽  
Dielectric Constants ◽  
Isothermal Heat Treatment ◽  
Coating Films ◽  
Ceramic Film ◽  
C Decomposition

BaTiO3-coating films were prepared from a solution containing poly(vinylpyrrolidone) (PVP) of molar composition Ba(CH3COO)2:Ti(OC2H5)4:PVP:CH3COOH:H2O: C2H5OH = 1:1:0.5:27:4:5, via nonrepetitive, single-step dip-coating. The gel films were found to be converted into BaTiO3 films via evaporation of the solvent and CH3COOH below 210 °C, decomposition of PVP at 210–360 °C, decomposition of CH3COO− below 440 °C, and crystallization at 500–610 °C. The decomposition of PVP was accompanied by the progress of the condensation reaction, which resulted in significant reduction in film thickness. When the gel films were heated isothermally at 700 °C, crack-free BaTiO3 films as thick as 0.9 μm were obtained. When the gel films were heated isothermally at 360 °C and then at 700 °C, the film became denser. Higher dielectric constants around 290 were found for the film that underwent the isothermal heat treatment at 360 °C. A slower rate of PVP decomposition was thought to be the key for the film densification.

Effect of L-Arginine on the Carbon Microsphere Forming under Hydrothermal Carbonization

2019 ◽  
Vol 41 (1) ◽  
pp. 72-72
Author(s):  
Jilei Liang Jilei Liang ◽  
Mengmeng Wu Mengmeng Wu ◽  
Hongmei Cai Hongmei Cai ◽  
Hao Wang Hao Wang ◽  
Hua Huang Hua Huang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Adsorption Capacity ◽  
Surface Property ◽  
Condensation Reaction ◽  
Hydrothermal Carbonization ◽  
Carbon Microspheres ◽  
N2 Adsorption ◽  
Sem Images ◽  
Ft Ir ◽  
Adsorption Desorption

Carbon microspheres (CMs) with a diameter of 5-10 μm have been synthesized by hydrothermal carbonization of starch and L-arginine. The surface property and structure of CMs were examined by FT-IR spectra, N2 adsorption-desorption isotherms and SEM images. These characterizations indicated that the L-arginine does not connect into the CMs but it promotes the starch hydrolysis and polymerization-condensation reaction of intermediate, which accelerates the formation of CMs and improves the yield in shorter time. The surface property of CMs determines adsorption capacity for acetic acid. By contrast, the porosity resulted from the carbonization at 500 and#176;C dominates the adsorption capacity for acetic acid.

Notizen: Improved 2,4-Dinitrophenylhydrazine, Thin Layer Chromatography Methods for the Determination of Micro- and Macroamounts of Ascorbic Acid

1974 ◽  
Vol 29 (11-12) ◽  
pp. 777-780 ◽  
Author(s):  
A. Navon ◽  
H. Z. Levinson
Keyword(s):  
Acetic Acid ◽  
Vitamin C ◽  
Thin Layer ◽  
Condensation Reaction ◽  
Dehydroascorbic Acid ◽  
Previous Method ◽  
Aqueous Acetic Acid ◽  
Tlc Plates ◽  
Layer Chromatography

Microamounts of vitamin C could be readily determined in 20 μl-samples using the 2,4-dinitrophenylhydrazine method together with separation by thin layer chromato­graphy. The condensation reaction was carried out for 5 min at 100 °C on a glass fibre disc. Purification of vitamin C hydrazones was accomplished by repeated separation on TLC plates. An aqueous solution of 65% acetic acid was em­ployed to dissolve the vitamin C hydrazones, providing maxi­mal absorbance at 500 nm. The minimum amount detectable by this method is 0.4 μg of dehydroascorbic acid. The macrodetermination of vitamin C was improved by simpli­fying a previous method and employing 65% aqueous acetic acid as a solvent for the hydrazones.

Sol-Gel Polymerization of Tetraalkoxygermanium and Organotrialkoxygermanium Monomers

1996 ◽  
Vol 431 ◽  
Author(s):  
Brigitta M. Baugher ◽  
Douglas A. Loy
Keyword(s):  
Chemical Modification ◽  
Sol Gel ◽  
Silica Gels ◽  
Germanium Oxide ◽  
Oxide Materials ◽  
Siloxane Bond ◽  
Mild Conditions ◽  
Condensation Reactions ◽  
Hydrolysis And Condensation ◽  
Opening Up

AbstractWhile the sol-gel polymerizations of tetraalkoxy- and organotrialkoxysilanes have been extensively studied, there have been few reports of similar investigations with the analogous tetraalkoxygermanium and organotrialkoxygermanium compounds. Germanium alkoxides have received less attention due, in part to their higher cost, but also their greater reactivity towards hydrolysis and condensation reactions. Germanium oxide materials are potentially interesting because the Ge-O-Ge linkage is labile (compared with the siloxane bond in silica gels and polysilsesquioxanes) opening up the possibility of further chemical modification of the polymeric architecture. This may permit hydrolytic reorganization of germanium oxide networks under relatively mild conditions. In this paper, we will present the results of our investigations of the solgel polymerizations of tetraethoxygermanium 1, tetraisopropoxygermanium 2, and methyltriethoxy-germanium 3 to afford network materials as both xerogels and aerogels.

NONTRADITIONAL METHOD OF CHEMICAL MODIFICATION OF THE SURFACE OF POROUS SILICA

2020 ◽  
Vol 54 (1 (251)) ◽  
pp. 33-37
Author(s):  
T.O. Kamalyan
Keyword(s):  
Chemical Modification ◽  
Porous Silica ◽  
Chemical Transport Reaction ◽  
Transport Reaction ◽  
Texture Parameters ◽  
Nontraditional Method ◽  
Modification Method ◽  
Gaseous Intermediate ◽  
Proposed Modification ◽  
Modification Of The Surface

The main results obtained in the study of the possibility of low-temperature chemical modification of porous silica, applying various nanodispersed substances to their surface are given. It has been shown that the use of the chemical transport reaction (CTR) $ \mathrm{H_{2}O_{2}/ZnO} $ for this purpose with the participation of $ \mathrm{H_{2}O_{2}} $ vapors at room temperature makes it possible to apply a number of oxides, sulfides and metal halides to the surface of various sorbents. An important advantage of the proposed modification method is that changes in the original texture parameters of the substrate are minimized. Using the example of modifying the behavior of highly pure $ \mathrm{SiO_{2}} $ with zinc oxide, it was shown that the decomposition of gaseous intermediate products of CTR $ \mathrm{H_{2}O_{2}/ZnO} $ occurs mainly in pores with a diameter of more than $ 6~nm $.

A novel solid acid catalyst synthesized from ZnAl2O4 spinel and its application in the esterification of acetic acid and n-butyl alcohol

RSC Advances ◽  
2015 ◽  
Vol 5 (25) ◽  
pp. 19652-19658 ◽  
Author(s):  
An-Qi Wang ◽  
Xiu-Ling Wu ◽  
Jun-Xia Wang ◽  
Hui Pan ◽  
Xiao-Yun Tian ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Catalytic Activity ◽  
Structural Stability ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Mesoporous Structure ◽  
Butyl Alcohol ◽  
Znal2o4 Spinel

A new spinel-style S2O82−/ZnAl2O4 catalyst with the mesoporous structure exhibited the well catalytic activity and structural stability.

Synthesis and Structure of 1-Substituted Benzopyrano- [4’,3’-c]benzo[3”,4”-ƒ]-2,8-dioxabicyclo[3.3.1]nonane

2006 ◽  
Vol 61 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Ilia Manolov ◽  
Caecilia Maichle-Moessmer ◽  
Elke Niquet
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Condensation Reaction ◽  
Potassium Acetate

AbstractThe base catalyzed condensation reaction between 4-hydroxycoumarin and 3-acetylcoumarin (3-benzoylcoumarin) in water at reflux led to the formation of 1-methyl (1-phenyl)- benzopyrano[4’,3’-c]-benzo[3”,4”-ƒ ]-2,8-dioxabicyclo[3.3.1]nonane (2a, b) as final products. When 4-hydroxycoumarin and 3-acetylcoumarin reacted in a glacial acetic acid in the presence of potassium acetate the final product was 7-[3-acetyl-2-oxo-3,4-dihydro-2H-[1]benzopyran-4-yl]methyl- 6H,14H,14bH-bis-([1]benzopyrano)[4,3-b:4’,3’-d]pyran-6,14-dione (4). 4-Hydroxycoumarin and 4-(5-bromo-2-hydroxyphenyl)-3-buten-2-one were condensed in water at reflux and 1- methylcoumarino-[4’,3’-c]-bromobenzo[3”,4”-ƒ ]-2,8-dioxabicyclo[3.3.1]nonane was a final product (3).

scholarly journals Synthesis and Characterization of Some New Benzimidazole Derivatives

2016 ◽  
Vol 13 (1) ◽  
pp. 82-88
Author(s):  
Baghdad Science Journal
Keyword(s):  
Acetic Acid ◽  
Mannich Base ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Secondary Amines ◽  
Synthesis And Characterization ◽  
Benzimidazole Derivatives ◽  
Schiff Base Derivatives ◽  
New Compounds

In this paper the new starting material 2-(5-chloro-1H-benzo[d]imidazole-2-yl) aniline (1) was synthesized by the condensation reaction of 4-chloro-o-phenylenediamine and anthranilic acid .The new Mannich base derivatives were synthesized using formaldehyde and different secondary amines to synthesize a new set of benzimidazole derivatives(2-5). Also, the new Schiff-base derivatives (6-10) were synthesized from the reaction of compound (1) with various aromatic aldehydes and the closure-ring was done successfully using mercapto acetic acid to get the new thiazolidine derivatives(11-12).These new compounds were characterized using some physical techniques like:FT-IR Spectra and 1HNMR Spectra.

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