The effect of the content of sulphonic acid groups of an ion exchanger upon its catalytic activity

1979 ◽  
Vol 44 (2) ◽  
pp. 502-507 ◽  
Author(s):  
Karel Setínek
Keyword(s):  
Surface Layer ◽  
Catalytic Activity ◽  
Liquid Phase ◽  
Alkali Metal ◽  
Reaction Rates ◽  
Sulphonic Acid ◽  
Ion Exchanger ◽  
Alkali Metal Ions ◽  
Initial Reaction ◽  
Different Thickness

Measurements of the initial reaction rates of the gas and liquid phase reesterification of ethyl acetate by 1-propanol catalyzed by an acid ion exchanger showed that the gradual neutralization of the acid groups by alkali metal ions in aqueous medium decreases uniformly their concentration within the whole mass of the catalyst, which reflects in the gradual decrease in the catalytic activity. On varying the content of sulphonic acid groups by sulphonation of the starting copolymer to a different degree, the ion exchangers possessing fully sulphonated surface layer of different thickness are formed which exhibit the same catalytic activity. The decrease in the activity has been observed only after the sulphonation degree was less than 50 per cent.

scholarly journals Enhanced Catalytic Dye Decolorization by Microencapsulation of Laccase from P. Sanguineus CS43 in Natural and Synthetic Polymers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1353
Author(s):  
Natalia Lopez-Barbosa ◽  
Ana Lucía Campaña ◽  
Juan C. Cruz ◽  
Nancy Ornelas-Soto ◽  
Johann F. Osma
Keyword(s):  
Catalytic Activity ◽  
Confocal Microscopy ◽  
Fluorescent Dyes ◽  
Fold Increase ◽  
Dye Decolorization ◽  
Reaction Rates ◽  
Lower Amount ◽  
Poly Vinyl Alcohol ◽  
Initial Reaction ◽  
Pycnoporus Sanguineus

Polymeric microcapsules with the fungal laccase from Pycnoporus sanguineus CS43 may represent an attractive avenue for the removal or degradation of dyes from wastewaters. Microcapsules of alginate/chitosan (9.23 ± 0.12 µm) and poly(styrenesulfonate) (PSS) (9.25 ± 0.35 µm) were synthesized and subsequently tested for catalytic activity in the decolorization of the diazo dye Congo Red. Successful encapsulation into the materials was verified via confocal microscopy of labeled enzyme molecules. Laccase activity was measured as a function of time and the initial reaction rates were recovered for each preparation, showing up to sevenfold increase with respect to free laccase. The ability of substrates to diffuse through the pores of the microcapsules was evaluated with the aid of fluorescent dyes and confocal microscopy. pH and thermal stability were also measured for encapsulates, showing catalytic activity for pH values as low as 4 and temperatures of about 80 °C. Scanning electron microscope (SEM) analyses demonstrated the ability of PSS capsules to avoid accumulation of byproducts and, therefore, superior catalytic performance. This was corroborated by the direct observation of substrates diffusing in and out of the materials. Compared with our PSS preparation, alginate/chitosan microcapsules studied by others degrade 2.6 times more dye, albeit with a 135-fold increase in units of enzyme per mg of dye. Similarly, poly(vinyl) alcohol microcapsules from degrade 1.7 times more dye, despite an eightfold increase in units of enzyme per mg of dye. This could be potentially beneficial from the economic viewpoint as a significantly lower amount of enzyme might be needed for the same decolorization level achieved with similar encapsulated systems.

scholarly journals Layer-Like Zeolite X as Catalyst in a Knoevenagel Condensation: The Effect of Different Preparation Pathways and Cation Exchange

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 474
Author(s):  
Jan-Paul Grass ◽  
Katharina Klühspies ◽  
Bastian Reiprich ◽  
Wilhelm Schwieger ◽  
Alexandra Inayat
Keyword(s):  
Catalytic Activity ◽  
Reaction Rate ◽  
Knoevenagel Condensation ◽  
Ethyl Cyanoacetate ◽  
Reaction Rates ◽  
Initial Reaction Rate ◽  
Comparative Investigation ◽  
Morphological Properties ◽  
Initial Reaction ◽  
Zeolite X

This study is dedicated to the comparative investigation of the catalytic activity of layer-like Faujasite-type (FAU) zeolite X obtained from three different synthesis routes (additive-free route, Li2CO3 route, and TPOAC route) in a liquid-phase Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate to ethyl trans-α-cyanocinnamate. It is shown that the charge-balancing cations (Na+ and K+) and the morphological properties have a strong influence on the apparent reaction rate and degree of conversion. The highest initial reaction rate could be found for the layer-like zeolite X synthesised by the additive-free route in the potassium form. In most cases, the potassium-exchanged zeolites enabled higher maximum conversions and higher reaction rates compared to the zeolite X catalysts in sodium form. However, very thin crystal plates (below 100 nm thickness), similar to those obtained in the presence of TPOAC, did not withstand the multiple aqueous ion exchange procedure, with the remaining coarse crystals facilitating less enhancement of the catalytic activity.

Ion Exchange Equilibria of Cobalt(II)-M-hexacyanoferrates(II) with K, NH4 and Cs

1979 ◽  
Vol 34 (9) ◽  
pp. 1275-1278 ◽  
Author(s):  
T. S. Ćeranić ◽  
R. Adamović
Keyword(s):  
Ion Exchange ◽  
Alkali Metal ◽  
Thermodynamic Functions ◽  
Thermodynamic Data ◽  
Ion Exchanger ◽  
Alkali Metal Ions ◽  
Inorganic Ion Exchanger ◽  
Inorganic Ion ◽  
Different Temperatures ◽  
Competing Ions

Abstract The inorganic ion exchanger cobalt(II)-M-hexacyanoferrate(II), M = K, NH4 and Cs, and its selectivity for the alkali metal ions are defined by their isotherms at three different temperatures and by the calculated thermodynamic functions ΔG°, ΔH° and ΔS°. The thermodynamic data are discussed on the basis of the radii of competing ions as well as on the steric limitations of the ion exchanger phase, i.e., the thermodynamic magnitudes which control the selectivity of those ion exchangers.

scholarly journals Effects of Some Alkali and Alkaline Earth Metal Ions on the Initial Reaction Rates of Congregibacter litoralis KT71 β-lactamase Hydrolysis of 4-Nitrophenyl Myristate

2021 ◽  
pp. 23-29
Author(s):  
O. M. Iniaghe ◽  
O. Ibukun
Keyword(s):  
Enzyme Activity ◽  
Metal Ions ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Reaction Rates ◽  
Alkaline Earth Metal ◽  
Alkali Metal Ions ◽  
Initial Reaction ◽  
Alkaline Earth Metal Ions ◽  
Hydrolysis Of

The effects of some alkali metal ions (Na+ and K+) and alkaline earth metal ions (Mg 2+ and Ba2+) on the initial reaction rates of Congregibacter litoralis KT71 β-lactamase hydrolysis of 4-nitrophenyl myristate was investigated by varying the concentrations of the metal ions in the assay mixture which comprised of 100 µl of standard enzyme solution, 200 µl of varying concentration of metal ions, 500 µl of 50 mM sodium phosphate buffer pH 7.5 and 200 µl of 4-nitrophenyl myristate (substrate) which was added last to the assay mixture after an incubation time of 10 minutes at 44 oC. The enzyme activity was measured spectrophotometrically using a UV-780 recording spectrophotometer at a wavelength of 405 nm. The hydrolysis of 4-nitrophenyl myristate to yield 4-nitrophenol was monitored by reading the absorbance at 25 minutes. Results showed that the alkaline earth metal ions (Ba2+ and Mg2+) had higher enzyme activation effect than the alkali metal ions (K+ and Na+) Also, all metal ions except Mg2+ showed enzyme stimulatory effect at low concentrations (<2 mM) but inhibitory at higher ion concentrations (2 mM - 3 mM). Mg 2+ caused a proportionate decrease in enzyme activity from its peak (when metal ion concentration was lowest). Results from this research is of great significance to the industrialist especially where the search for novel lipases with unique characteristics suitable for the industries are inevitable.

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