Zeolite Syntheses from Superalkaline Reaction Mixtures

1992 ◽  
Vol 57 (4) ◽  
pp. 788-793 ◽  
Author(s):  
Falk Fischer ◽  
Marianne Hadan ◽  
Günter Fiedrich
Keyword(s):  
Ir Spectroscopy ◽  
Crystalline Phase ◽  
Ion Concentration ◽  
Single Crystalline ◽  
Hydroxyl Ion ◽  
Type Zeolite

The synthesis of faujasite-type zeolite from superalkaline reaction mixtures are described. The contribution shows the influence of component K2O added in the system Na2O-Al2O3-SiO2-H2O with H2O/(K2O + Na2O) = 13-15. The reaction course was investigated in the range K2O/(K2O + Na2O) from about 0.07 to 0.5. Under used conditions it is quite possible to isolate faujasite-type zeolite as a single crystalline phase. By means of IR spectroscopy, low SiO2/Al2O3 ratios from 2.0 to 2.1 in the faujasite framework have been indicated. The low SiO2/Al2O3 ratios are interpreted by a higher stability of the Si-O-Al- than the Si-O-Si- bond with increasing hydroxyl ion concentration.

Preparation of Macroprous C12A7 Mayenite Monoliths via a Sol-Gel Process with Nitrates as Precursors

2018 ◽  
Vol 768 ◽  
pp. 211-217 ◽  
Author(s):  
Rui Wang ◽  
Yu Kun Sun ◽  
Bao Jia Qi Jiang ◽  
Hui Yang ◽  
Xing Zhong Guo
Keyword(s):  
Heat Treatment ◽  
Phase Separation ◽  
Binary System ◽  
Propylene Oxide ◽  
Crystalline Phase ◽  
Sol Gel ◽  
Single Crystalline ◽  
Sol Gel Process

Macroporous Ca12Al14O33(C12A7) mayenite monoliths have been successfully prepared via a sol-gel process in the presence of propylene oxide (PO) and poly (ethyleneoxide) (PEO). Gelation of CaO-Al2O3binary system with nitrates salts as additional precursors is accelerated by PO as an acid scavenger, while PEO works as a phase separation inducer to mediate the phase separation of the system. Appropriate PO and PEO amounts allow the formation of monolithic xerogel with interconnected macropores and co-continuous skeletons. The resultant dried gels are amorphous and the single crystalline phase Ca12Al14O33mayenite forms after heat-treatment at 1100 °C in air, while the macrostructure is preserved with a porosity as high as 78% and smoother and denser skeletons.

Determination of the charge of Al13 Keggin oligocations intercalated into synthetic hectorite

2019 ◽  
Vol 74 (1) ◽  
pp. 85-90
Author(s):  
Marius Schöttle ◽  
Dominik Schuchardt ◽  
Andreas Edenharter ◽  
Sebastian Koch ◽  
Jürgen Senker ◽  
...  
Keyword(s):  
Reaction Time ◽  
Solid State ◽  
Ir Spectroscopy ◽  
Cation Exchange ◽  
Elemental Analysis ◽  
Crystalline Phase ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
A Charge

AbstractApplying a nematic liquid crystalline phase of a synthetic Na-hectorite with layer separations >100 nm, the reaction time for pillaring with Al13 Keggin oligocation could be reduced to seconds ensuring that cation exchange is controlled by thermodynamics. With this material at hand we are able to resolve the long-standing dispute regarding the charge of intercalated Keggin oligocations. Micropore sizes as determined by physisorption isotherms, adsorption isotherms obtained via elemental analysis, and results of 27Al solid-state NMR and pyridine probe IR spectroscopy favor a charge of +7 for the Al13 pillars intercalated into hectorite unaltered.

scholarly journals OPTIMIZATION OF TIME REACTION AND HYDROXIDE ION CONCENTRATION ON FLAVONOID SYNTHESIS FROM BENZALDEHYDE AND ITS DERIVATIVES

2010 ◽  
Vol 5 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Sri Handayani ◽  
Sunarto, Sunarto, ◽  
Susila Kristianingrum
Keyword(s):  
Reaction Time ◽  
Optimum Concentration ◽  
Ion Concentration ◽  
Optimum Time ◽  
Hydroxide Ion ◽  
Synthesis Time ◽  
Flavonoid Synthesis ◽  
Hydroxyl Ion ◽  
Optimum Reaction ◽  
Time Of Reaction

The aim of this research is to determine the optimum time of reaction and concentration of hydroxide ion on chalcone, 4-methoxychalcone and 3,4-dimethoxychalcone synthesis. Chalcone and its derivatives were synthesized by dissolving KOH in ethanol followed by dropwise addition of acetophenone and benzaldehyde. Then, the mixture was stirred for several hours. Three benzaldehydes has been used, i.e : benzaldehyde, p-anysaldehyde and veratraldehyde. The time of reaction was varied for, 12, 18, 24, 30 and 36 hours. Furthermore, on the optimum reaction time for each benzaldehyde the hydroxyl ion concentration was varied from 5,7,9,11 and 13%(w/v). The results of this research suggested that the optimum time of chalchone synthesis was 12 hours, while, 4-methoxychalcone and 3,4-dimethoxychalcone were 30 hours. The optimum concentration of hydroxide ion of chalcone synthesis was 13% and for 4-methoxychalcone and 3,4-dimethoxychalcone were 11%. Keywords: Chalcone synthesis, time of reaction, hydroxide ion concentration.

Single-Crystalline-Phase Mo3VOx: An Efficient Catalyst for the Partial Oxidation of Acrolein to Acrylic Acid

ChemCatChem ◽  
2013 ◽  
Vol 5 (10) ◽  
pp. 2869-2873 ◽  
Author(s):  
Chen Chen ◽  
Nakatani Kosuke ◽  
Toru Murayama ◽  
Wataru Ueda
Keyword(s):  
Acrylic Acid ◽  
Partial Oxidation ◽  
Crystalline Phase ◽  
Efficient Catalyst ◽  
Single Crystalline

The Effect of Hydroxyl Ion Concentration (or ofpH) on the Film Potentials of Multilayers

1939 ◽  
Vol 55 (3) ◽  
pp. 320-321 ◽  
Author(s):  
William D. Harkins ◽  
Richard W. Mattoon
Keyword(s):  
Ion Concentration ◽  
Hydroxyl Ion

Reversible Diastereoselective Photocyclization of a Diarylethene in a Single-Crystalline Phase

2000 ◽  
Vol 122 (40) ◽  
pp. 9631-9637 ◽  
Author(s):  
Tetsuhiro Kodani ◽  
Kenji Matsuda ◽  
Taro Yamada ◽  
Seiya Kobatake ◽  
Masahiro Irie
Keyword(s):  
Crystalline Phase ◽  
Single Crystalline

Photochromism and Photomagnetism of Biindenylidene-Dione Derivative in a Single Crystalline Phase

2002 ◽  
Vol 389 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Lili Xu ◽  
Jiben Meng ◽  
Hui Wang ◽  
Ping Li ◽  
Teruki Sugiyama ◽  
...  
Keyword(s):  
Crystalline Phase ◽  
Single Crystalline ◽  
Dione Derivative

THE MECHANISMS OF PERMANGANATE OXIDATION VI. THE OXIDATION OF CYANIDE ION

1960 ◽  
Vol 38 (11) ◽  
pp. 2237-2255 ◽  
Author(s):  
Ross Stewart ◽  
R. Van der Linden
Keyword(s):  
Salt Effect ◽  
Ion Concentration ◽  
Cyanide Ion ◽  
Barium Ions ◽  
Ion Concentrations ◽  
Permanganate Oxidation ◽  
Parallel Processes ◽  
Hydroxyl Ion ◽  
Kinetic Expression ◽  
Tracer Experiments

Kinetic and oxygen-18 tracer experiments have been used in an attempt to elucidate the mechanism(s) of permanganate oxidation of cyanide. From pH 12 to 14.6 the oxidation is represented by the equation,[Formula: see text]From pH 12 to 6 the reaction was found to be complex and unstoichiometric yielding cyanate, carbon dioxide, cyanide ion, and finally cyanogen at pH 9 to 6.The rate of reduction of permanganate, as followed iodometrically and spectrophotometrically, is found to be markedly dependent on the pH of the medium and reactant concentration. The rate is negligible in acid solution but rapid in basic media.At pH greater than 12 two parallel processes are indicated which have been designated as reaction A and reaction B. Reaction A appears at low reactant concentrations 0.0004 M cyanide and higher hydroxyl ion concentrations pH 13 and is represented by the kinetic expression[Formula: see text]where k2 is independent of hydroxyl ion concentration and is insensitive to the presence of manganate and barium ions. A positive salt effect is observed and labeling experiments using permanganate enriched in oxygen18 showed that the oxygen introduced into the product cyanate comes mainly from the oxidant (70%–80% oxygen-18 transferred).The existence of a second process reaction B was indicated by the changing kinetics at higher reactant concentrations and lower basicities, by the non-linear Arrhenius plots, and by the observation that only 15–25% oxygen-18 transfer from permanganate to substrate had occurred at pH 13. The rate of this latter process is approximately represented by the kinetic expression[Formula: see text]These reactions are discussed in terms of mechanism

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