scholarly journals The Effect of Aromatic Tertiary Amines on the Copper(II) Catalyzed Decarboxylation of 3-Oxo-Glutaric Acid

1972 ◽  
Vol 50 (10) ◽  
pp. 1461-1467
Author(s):  
K. N. Leong ◽  
M. W. Lister
Keyword(s):  
Copper Complexes ◽  
Glutaric Acid ◽  
Catalytic Effect ◽  
Copper Ions ◽  
Equilibrium Constants ◽  
Copper Ion ◽  
Tertiary Amines ◽  
Selective Electrode ◽  
Equilibrium Concentrations ◽  
Kinetics Of

The kinetics of the copper(II) catalyzed decarboxylation of 3-oxo-glutaric acid have been investigated in unbuffered solutions at 25 °C and 0.60 M ionic strength, both in the presence of aromatic tertiary amines, and with hydrated copper ions alone. The amines used were 2,2′-bipyridyl and 1,10-phenanthroline. Equilibrium constants for the formation of the various copper complexes were determined with a copper ion selective electrode, particularly for the species CuAB, where A is the 3-oxo-glutarate ion, and B is an aromatic amine. The kinetic behavior was then interpreted as arising from the simultaneous decarboxylation of all the species present containing a 3-oxo-glutarate ligand. The resulting rate constants indicated that some kinetic effect was transmitted through the copper from the base to the 3-oxo-glutarate, but the effect was relatively small, and the bulk of the catalytic effect caused by the base arose from changes in equilibrium concentrations.

Kinetics of reconstitution of apotyrosinase by copper

1990 ◽  
Vol 68 (2) ◽  
pp. 476-479
Author(s):  
Donald C. Wigfield ◽  
Douglas M. Goltz
Keyword(s):  
Rate Constant ◽  
Copper Concentration ◽  
Copper Ions ◽  
Copper Ion ◽  
Order Rate Constant ◽  
First Order ◽  
Order Rate ◽  
Pseudo First Order ◽  
Rate Limiting ◽  
Kinetics Of

The kinetics of the reconstitution reaction of apotyrosinase with copper (II) ions are reported. The reaction is pseudo first order with respect to apoenzyme and the values of these pseudo first order rate constants are reported as a function of copper (II) concentration. Two copper ions bind to apoenzyme, and if the second one is rate limiting, the kinetically relevant copper concentration is the copper originally added minus the amount used in binding the first copper ion to enzyme. This modified copper concentration is linearly related to the magnitude of the pseudo first order rate constant, up to a copper concentration of 1.25 × 10−4 M (10-fold excess), giving a second order rate constant of 7.67 × 102 ± 0.93 × 102 M−1∙s−1.Key words: apotyrosinase, copper, tyrosinase.

The kinetics of metal uptake by microbial biomass: implications for the design of a biosorption reactor

1998 ◽  
Vol 38 (6) ◽  
pp. 279-286 ◽  
Author(s):  
T.J. Butter ◽  
L.M. Evison ◽  
I.C. Hancock ◽  
F.S. Holland
Keyword(s):  
Retention Time ◽  
Metal Uptake ◽  
Copper Ions ◽  
Plug Flow ◽  
Settling Tank ◽  
Copper Ion ◽  
Biomass Concentration ◽  
Free Cell ◽  
Cell Suspensions ◽  
Kinetics Of

The kinetics of copper ion biosorption by free cell suspensions of inactivated Penicillium biomass was investigated. During the first 15 seconds of the metal uptake reaction copper biosorption was extremely rapid, becoming progressively slower until equilibrium was achieved. At a biomass concentration of 5.48 g dry weight/l, the copper biosorption reaction reached approximately 90% of the equilibrium position in one minute. This is in contrast with biosorption onto immobilised biomass which is known to take up to 24 hours or longer to reach equilibrium. However, the conventional reactor design for free cell suspensions, the stirred tank, may make inefficient use of the equipment and process due to the extended retention time. A plug-flow biosorption reactor with a limited retention time has been developed and demonstrated in the laboratory. The biomass and metal solution were mixed together using static in-line mixers and pumped along a length of pipe before discharging the mixed liquor into a settling tank to achieve phase separation. Desorption of the bound copper ions was achieved by drawing an eluant solution through metal-loaded biomass immobilised as a filter cake. The combination of metal uptake using free cells, and desorption using immobilised cells, optimises the kinetic and mass transfer effects for both processes and minimises the equipment requirements.

The Effect of Aromatic Amines on the Catalyzed Decarboxylation of 3-Oxo-glutaric Acid

1972 ◽  
Vol 50 (22) ◽  
pp. 3573-3586 ◽  
Author(s):  
K. N. Leong ◽  
M. W. Lister
Keyword(s):  
Ionic Strength ◽  
Stability Constants ◽  
Rate Constants ◽  
Aromatic Amines ◽  
Copper Complexes ◽  
Glutaric Acid ◽  
Equilibrium Constants ◽  
Nickel Compound ◽  
Ph Measurements ◽  
Cobalt Nickel

Equilibrium constants have been measured for the formation of MA species, where M is divalent manganese, cobalt, nickel, or zinc, and A2− is the 3-oxo-glutarate ion. Equilibrium constants have also been measured for the reactions [Formula: see text], where B is 2,2′-bipyridyl or 1,10-phenanthroline. These constants were obtained by pH measurements at 25 °C and an ionic strength of 0.60. The results are compared with those for similar systems, especially as regards the tendency to form ternary mixed complexes of the type MAB.The rates of decarboxylation of the various MA and MAB species have been measured. The resulting rate constants follow the Irving–Williams order for stability constants, except that in both MAB species the cobalt compound decomposed slightly faster than the nickel compound. The aromatic base, which had been found earlier to have very little effect in copper complexes, increased the rate constants appreciably with other metals, especially with manganese and zinc. Usually 1,10-phenanthroline has a larger effect than 2,2′-bipyridyl. Some possible explanations of the results are considered.

Kinetics of Copper Ion Leaching from Cement-Solidified Body of Blast Furnace Slag Adsorbing Copper Ion

2021 ◽  
Vol 1035 ◽  
pp. 1036-1042
Author(s):  
Ya Li Wang ◽  
Zi Mo Li ◽  
Ning Yang ◽  
Qi Wei ◽  
Li Wei Hao
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Heavy Metal Ions ◽  
Copper Ions ◽  
Copper Ion ◽  
Slag Cement ◽  
Cement System ◽  
Kinetics Of ◽  
Furnace Slag ◽  
Solidified Body

Blast furnace slag has good adsorption performance and can be used to adsorb heavy metal ions in waste liquid. It’s worth studying whether the blast furnace slag absorbing heavy metal ions will pose a potential threat to the environment during the process when used in cement-based materials.This paper has studied the leaching amount of copper ions in the blast furnace slag-cement system was analyzed, and analyzed the leaching kinetics of copper ions. The results showed that the leaching amount of copper ions in the blast furnace slag-cement system that adsorbed copper ions basically met the national standard, and the solidified body age was 28 days,blast furnace slag content 30% is the smallest condition for the amount of copper ion leaching.The leaching model of copper ions in the blast furnace slag-cement system is the Elovich equation, which is a heterogeneous diffusion process. The longer the curing age is the slower the leaching process is completed and do not cause environmental pollution during long-term use.

scholarly journals Recognition of hydrogen isotopomers by an open-cage fullerene

2013 ◽  
Vol 371 (1998) ◽  
pp. 20110629 ◽  
Author(s):  
Yasujiro Murata ◽  
Shih-Ching Chuang ◽  
Fumiyuki Tanabe ◽  
Michihisa Murata ◽  
Koichi Komatsu
Keyword(s):  
Equilibrium Constants ◽  
Equilibrium Mixture ◽  
Size Difference ◽  
Binding Affinities ◽  
Kinetic Isotope ◽  
Molecular Sizes ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Pressure Hydrogen

We present our study on the recognition of hydrogen isotopes by an open-cage fullerene through determination of binding affinity of isotopes H 2 /HD/D 2 with the open-cage fullerene and comparison of their relative molecular sizes through kinetic-isotope-release experiments. We took advantage of isotope H 2 /D 2 exchange that generated an equilibrium mixture of H 2 /HD/D 2 in a stainless steel autoclave to conduct high-pressure hydrogen insertion into an open-cage fullerene. The equilibrium constants of three isotopes with the open-cage fullerene were determined at various pressures and temperatures. Our results show a higher equilibrium constant for HD into open-cage fullerene than the other two isotopomers, which is consistent with its dipolar nature. D 2 molecule generally binds stronger than H 2 because of its heavier mass; however, the affinity for H 2 becomes larger than D 2 at lower temperature, when size effect becomes dominant. We further investigated the kinetics of H 2 /HD/D 2 release from open-cage fullerene, proving their relative escaping rates. D 2 was found to be the smallest and H 2 the largest molecule. This notion has not only supported the observed inversion of relative binding affinities between H 2 and D 2 , but also demonstrated that comparison of size difference of single molecules through non-convalent kinetic-isotope effect was applicable.

scholarly journals An Investigation on Design and Characterization of a Highly Selective LED Optical Sensor for Copper Ions in Aqueous Solutions

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1099
Author(s):  
Sheng-Chun Hung ◽  
Chih-Cheng Lu ◽  
Yu-Ting Wu
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Copper Ions ◽  
Incident Light ◽  
Copper Ion ◽  
Intensity Change ◽  
Optical Absorbance ◽  
Sensing System ◽  
Optic Sensor ◽  
Cu Ions

The optical characteristics of copper ion detection, such as the photometric absorbance of specific wavelengths, exhibit significant intensity change upon incident light into the aqueous solutions with different concentrations of metal ions due to the electron transition in the orbit. In this study, we developed a low-cost, small-size and fast-response photoelectric sensing prototype as an optic sensor for copper (Cu) ions detection by utilizing the principle of optical absorption. We quantified the change of optical absorbance from infra-red (IR) light emitting diodes (LEDs) upon different concentrations of copper ions and the transmitted optical signals were transferred to the corresponding output voltage through a phototransistor and circuit integrated in the photoelectric sensing system. The optic sensor for copper (Cu) ions demonstrated not only excellent specificity with other metal ions such as cadmium (Cd), nickel (Ni), iron (Fe) and chloride (Cl) ions in the same aqueous solution but also satisfactory linearity and reproducibility. The sensitivity of the preliminary sensing system for copper ions was 29 mV/ppm from 0 to 1000 ppm. In addition, significant ion-selective characteristics and anti-interference capability were also observed in the experiments by the proposed approach.

Catalytic effect of in situ formed Mg2Ni and REH (RE: Ce and Y) on thermodynamics and kinetics of Mg-RE-Ni hydrogen storage alloy

2020 ◽  
Vol 157 ◽  
pp. 828-839 ◽  
Author(s):  
Hui Yong ◽  
Shihai Guo ◽  
Zeming Yuan ◽  
Yan Qi ◽  
Dongliang Zhao ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Catalytic Effect ◽  
Hydrogen Storage Alloy ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of

Automated Fluoride Ion Determination

1977 ◽  
Vol 14 (1-6) ◽  
pp. 269-274 ◽  
Author(s):  
David C. Cowell
Keyword(s):  
Continuous Flow ◽  
Ion Concentration ◽  
Fluoride Ion ◽  
Selective Electrode ◽  
Automated Method ◽  
Electrode Response ◽  
Kinetics Of ◽  
Fluoride Ion Selective Electrode ◽  
Flow Techniques

An automated method is described, using standard continuous flow techniques, for the determination of urine fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in urine, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 83 to 90%; in-batch precision is between 0·9 and 1·6% and carryover 2·5% or less.

Biomimetic synthesis of needle-like fluorescent calcium phosphate/carbon dot hybrid composites for cell labeling and copper ion detection

2016 ◽  
Vol 45 (18) ◽  
pp. 7665-7671 ◽  
Author(s):  
Shanshan Guo ◽  
Shousi Lu ◽  
Pingxiang Xu ◽  
Yi Ma ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Drinking Water ◽  
Calcium Phosphate ◽  
Copper Ions ◽  
Hybrid Composites ◽  
Copper Ion ◽  
Cell Labeling ◽  
Biomimetic Synthesis ◽  
Selective Detection ◽  
Sodium Carboxymethylcellulose ◽  
Biomimetic Method

We report a biomimetic method to synthesize needle-like calcium phosphate (CaP) using carbon dots (CDs) and sodium carboxymethylcellulose as dual templates. The CaP/CDs were capable of cell labeling and selective detection of copper ions in drinking water.

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