A reaction-solution calorimeter for the undergraduate laboratory

1992 ◽  
Vol 69 (11) ◽  
pp. 940 ◽  
Author(s):  
H. P. Diogo ◽  
M. E. Minas da Piedade ◽  
J. J. Moura Ramos ◽  
J. A. Simoni ◽  
J. A. Martinho Simões
Keyword(s):  
Reaction Solution ◽  
Undergraduate Laboratory ◽  
Solution Calorimeter

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

Belousov–Zhabotinskii type oscillation reaction with glycerol and kinetics of reactions between the system components

1987 ◽  
Vol 52 (10) ◽  
pp. 2375-2382 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Peter Ševčík
Keyword(s):  
Oscillation System ◽  
Chemical Oscillations ◽  
Oscillation Reaction ◽  
Reaction Solution ◽  
System Components ◽  
Probable Source ◽  
Belousov Zhabotinskii Reaction ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Type Oscillation

Glycerol causes chemical oscillations in Belousov-Zhabotinskii reaction in a closed system as well as in a reaction solution bubbled with nitrogen. Since the oxidation of glycerol with bromate ions does not proceed autocatalytically and bromine in the oxidation state 0 or +1 in the absence of light does not react with glycerol, hydrolysis of bromine is the probable source of bromide ions in the studied oscillation system.

An Introduction to Nonlinear Chemical Dynamics

1998 ◽  
Author(s):  
Irving R. Epstein ◽  
John A. Pojman
Keyword(s):  
Flow Reactor ◽  
Chemical Dynamics ◽  
Design Data ◽  
Chemical Oscillators ◽  
Starting Point ◽  
Hands On ◽  
Undergraduate Laboratory ◽  
History Of ◽  
Mechanistic Basis ◽  
Nonlinear Chemical Dynamics

Just a few decades ago, chemical oscillations were thought to be exotic reactions of only theoretical interest. Now known to govern an array of physical and biological processes, including the regulation of the heart, these oscillations are being studied by a diverse group across the sciences. This book is the first introduction to nonlinear chemical dynamics written specifically for chemists. It covers oscillating reactions, chaos, and chemical pattern formation, and includes numerous practical suggestions on reactor design, data analysis, and computer simulations. Assuming only an undergraduate knowledge of chemistry, the book is an ideal starting point for research in the field. The book begins with a brief history of nonlinear chemical dynamics and a review of the basic mathematics and chemistry. The authors then provide an extensive overview of nonlinear dynamics, starting with the flow reactor and moving on to a detailed discussion of chemical oscillators. Throughout the authors emphasize the chemical mechanistic basis for self-organization. The overview is followed by a series of chapters on more advanced topics, including complex oscillations, biological systems, polymers, interactions between fields and waves, and Turing patterns. Underscoring the hands-on nature of the material, the book concludes with a series of classroom-tested demonstrations and experiments appropriate for an undergraduate laboratory.

Kinetics of Sequential Protopectin Degradation in a Flowing Reaction Solution

2020 ◽  
Vol 52 (4) ◽  
pp. 291-296
Author(s):  
D. A. Slobodova ◽  
R. M. Gorshkova ◽  
N. P. Novoselov ◽  
D. Kh. Khalikov
Keyword(s):  
Reaction Solution ◽  
Kinetics Of

Statistical Description of Isotope Exchange Processes: A Multisite Model for the 18O Exchange

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1161-1169 ◽  
Author(s):  
Paul Rösch
Keyword(s):  
Active Site ◽  
Isotope Exchange ◽  
Analytical Procedure ◽  
Matrix Formalism ◽  
Model Calculations ◽  
Exchange Processes ◽  
Reaction Solution ◽  
Different Types ◽  
Refinement Procedure

Abstract An analytical procedure has been developed for the determination of isotope exchange processes as exemplified by the 18O exchange catalysed by enzyme-nucleotide complexes. The model is able to handle more than one type of active site per reaction solution and is also able to distinguish between different types of inequivalence of the oxygens of enzyme bound Pi. Use of transition matrix formalism and basic statistical considerations lead directly to the simple model. A data refinement procedure is introduced and model calculations are shown.

Process Optimization of the Preparation of TiO2 Microcapsule Used for Photo-Catalytic Degradation with Ultrasound Irradiation

2012 ◽  
Vol 627 ◽  
pp. 770-774
Author(s):  
Xiao Mei Wang ◽  
Bao Bao Zhao ◽  
Cheng Rong Zhang
Keyword(s):  
Process Optimization ◽  
Ultrasound Irradiation ◽  
Core Material ◽  
Wall Material ◽  
Ultrasonic Power ◽  
Complex Coacervation ◽  
Photo Degradation ◽  
Reaction Solution ◽  
Ultrasonic Time ◽  
Ultrasonic Conditions

Microcapsules were prepared using the complex coacervation method with nano anatase TiO2 as the core material, gelatin/Arabia gum as the wall material, while dispersing TiO2 into the reaction solution using the ultrasonic. The prepared microcapsules can be finished into textiles such as the polypropylene nonwovens, and the microcapsules in the textiles gradually fracture and the anatase TiO2 was released, which would facilitate photo-degradation of the polypropylene nonwovens when exposed in sunlight. The microcapsules size was used as the process optimization evaluation index, and the quadratic general revolving combination design was used to conduct the experiments for obtaining the optimum ultrasonic conditions, and the other progress parameters were the same that used in our early microcapsule preparation. The obtained optimal process for ultrasound is: ultrasonic time is 17min; ultrasonic power is 74W and ultrasound temperature 60 °C.

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