A Mechanistic Study on the Electrocoagulation of Silica Nanoparticles from Polishing Wastewater

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
W. Den ◽  
C. Huang ◽  
H.-C. Ke
Keyword(s):  
Reaction Time ◽  
Zeta Potential ◽  
Continuous Flow ◽  
The Other ◽  
Mechanistic Study ◽  
Iron Hydroxides ◽  
Ferrous Ions ◽  
Silica Removal ◽  
Sludge Characterization ◽  
Oppositely Charged

The removal mechanisms involved in the continuous-flow electrocoagulation for the treatment of a polishing wastewater containing negatively charged silica particles are described in the report. The mechanisms are derived from the experimental measurement of pH, zeta-potential and turbidity as a function of reaction time, as well as from the sludge characterization. Two types of distinct mechanisms are proposed, one involving particle destabilization by oppositely charged ferrous ions, the other involving a complexation or physical bridging by iron hydroxides/hydroxyl complexes. The former mechanism is apparently responsible for the formation of “surface sludge”, whereas the latter mechanism is responsible for the sediment sludge. Both mechanisms are important to the silica removal based on the measurement of sludge quantity.

scholarly journals Development of a heating reactor for a continuous flow-through application in urea measurement

2003 ◽  
Vol 25 (6) ◽  
pp. 129-132
Author(s):  
S. S. Randhawa ◽  
A. K. Ganju ◽  
R. P. Bajpai
Keyword(s):  
Performance Evaluation ◽  
Reaction Time ◽  
Temperature Sensor ◽  
Continuous Flow ◽  
Silicone Oil ◽  
The Other ◽  
Peltier Effect ◽  
Different Temperatures ◽  
Flow Through ◽  
Biochemical Analyses

In most biochemical analyses, a flow-through heating arrangement is needed to reduce the reaction time or maintain a constant temperature. A rectangular reactor is described that is constructed of aluminium, is hollow inside and is filled with silicone oil. The glass coil through which the solution flows is immersed in the silicone oil. The heater, a Peltier-effect heat pump, on one side and the temperature sensor on the other side of the reactor body are embedded for heating and temperature control. The brief performance evaluation of the reactor is discussed by measuring the absorbance of urea concentration at different temperatures.

Visible Light-Mediated Oxidative Debenzylation

2020 ◽  
Author(s):  
Cristian Cavedon ◽  
Eric T. Sletten ◽  
Amiera Madani ◽  
Olaf Niemeyer ◽  
Peter H. Seeberger ◽  
...  
Keyword(s):  
Reaction Time ◽  
Visible Light ◽  
Functional Groups ◽  
Continuous Flow ◽  
Protecting Groups ◽  
Benzyl Ether ◽  
Complex Molecules ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Harsh Conditions

Protecting groups are key in the synthesis of complex molecules such as carbohydrates to distinguish functional groups of similar reactivity. The harsh conditions required to cleave stable benzyl ether protective groups are not compatible with many other protective and functional groups. The mild, visible light-mediated debenzylation disclosed here renders benzyl ethers orthogonal protective groups. Key to success is the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as stoichiometric or catalytic photooxidant such that benzyl ethers can be cleaved in the presence of azides, alkenes, and alkynes. The reaction time for this transformation can be reduced from hours to minutes in continuous flow. <br>

scholarly journals Achieving selectivity in porphyrin bromination through a DoE-driven optimization under continuous flow conditions

2020 ◽  
Author(s):  
Paolo Zardi ◽  
Michele Maggini ◽  
Tommaso Carofiglio
Keyword(s):  
Reaction Time ◽  
Design Of Experiment ◽  
Continuous Flow ◽  
Optimization Process ◽  
Porphyrin Ring ◽  
Flow Conditions ◽  
Reaction Parameters ◽  
Synthetic Procedure ◽  
Relevant Factors ◽  
Post Functionalization

AbstractThe post-functionalization of porphyrins through the bromination in β position of the pyrrolic rings is a relevant transformation because the resulting bromoderivatives are useful synthons to covalently link a variety of chemical architectures to a porphyrin ring. However, single bromination of porphyrins is a challenging reaction for the abundancy of reactive β-pyrrolic positions in the aromatic macrocycle. We herein report a synthetic procedure for the efficient preparation of 2-bromo-5,10,15,20-tetraphenylporphyrin (1) under continuous flow conditions. The use of flow technology allows to reach an accurate control over critical reaction parameters such as temperature and reaction time. Furthermore, by performing the optimization process through a statistical DoE (Design of Experiment) approach, these parameters could be properly adjusted with a limited number of experiments. This process led us to a better understanding of the relevant factors that govern porphyrins monobromination and to obtain compound 1 with an unprecedent 80% yield.

scholarly journals PROBING THE CONSTRUCT VALIDITY OF LLAMA_D AS A MEASURE OF IMPLICIT LEARNING APTITUDE

2021 ◽  
pp. 1-14
Author(s):  
Yuichi Suzuki
Keyword(s):  
Reaction Time ◽  
Construct Validity ◽  
Implicit Learning ◽  
Incidental Learning ◽  
The Other ◽  
Aptitude Test ◽  
Oral Fluency ◽  
The Relationship ◽  
Potential Test ◽  
Confidence Ratings

Abstract A subtest of the LLAMA test battery (LLAMA_D) has been proposed as a potential test of implicit learning aptitude. To improve its construct validity, in the present study, the original LLAMA_D (a) instructions for incidental learning were modified, and (b) confidence ratings of test responses and (c) reaction time (RT) measurements were added. This revised LLAMA_D was administered along with the other LLAMA subtests (LLAMA-B, -E, and -F). Unconscious knowledge that may (not) result from the exposure was assessed through the relationship between the accuracy/RT and confidence ratings. The results suggest that LLAMA_D accuracy largely reflects conscious retrieval of previously heard sound sequences. However, an index derived from the LLAMA_D RT measure (coefficient of variance) was associated with an aspect of oral fluency, which is presumably dependent on proceduralization. Several recommendations are proposed to redesign and extend LLAMA_D as a potential aptitude test for proceduralization.

scholarly journals Continuous-Flow Processes for the Production of Floxacin Intermediates: Efficient C–C Bond Formation through a Rapid and Strong Activation of Carboxylic Acids

2020 ◽  
Vol 02 (03) ◽  
pp. e128-e132
Author(s):  
Shao-Zheng Guo ◽  
Zhi-Qun Yu ◽  
Wei-Ke Su
Keyword(s):  
Reaction Time ◽  
Continuous Flow ◽  
Flow System ◽  
Bond Formation ◽  
Product Yield ◽  
Raw Material ◽  
Material Consumption ◽  
Tank Reactor ◽  
Mild Conditions ◽  
Flow Processes

AbstractThe development of highly efficient C–C bond formation methods for the synthesis of ethyl 2-(2,4-dichloro-5-fluorobenzoyl)-3-(dimethylamino)acrylate 1 in continuous flow processes has been described, which is based on the concept of rapid and efficient activation of carboxylic acid. 2,4-Dichloro-5-fluorobenzoic acid is rapidly converted into highly reactive 2,4-dichloro-5-fluorobenzoyl chloride by treating with inexpensive and less-toxic solid bis(trichloromethyl)carbonate. And then it rapidly reacts with ethyl 3-(dimethylamino)acrylate to afford the desired 1. This process can be performed under mild conditions. Compared with the traditional tank reactor process, less raw material consumption, higher product yield, less reaction time, higher operation safety ensured by more the environmentally friendly procedure, and process continuity are achieved in the continuous-flow system.

Degradation of chlorpyriphos in water by advanced oxidation processes

2010 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. Murillo ◽  
J. Sarasa ◽  
M. Lanao ◽  
J. L. Ovelleiro
Keyword(s):  
Reaction Time ◽  
Light Source ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
The Other ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Oxidation Processes ◽  
Other Hand ◽  
Initial Ph

The degradation of chlorpyriphos by different advanced oxidation processes such as photo-Fenton, TiO2, TiO2/H2O2, O3 and O3/H2O2 was investigated. The photo-Fenton and TiO2 processes were optimized using a solar chamber as light source. The optimum dosages of the photo-Fenton treatment were: [H2O2]=0.01 M; [Fe3 + ]=10 mg l−1; initial pH = 3.5. With these optimum conditions total degradation was observed after 15 minutes of reaction time. The application of sunlight was also efficient as total degradation was achieved after 60 minutes. The optimum dosage using only TiO2 as catalyst was 1,000 mg l−1, obtaining the maximum degradation at 20 minutes of reaction time. On the other hand, the addition of 0.02 M of H2O2 to a lower dosage of TiO2 (10 mg l−1) provides the same degradation. The ozonation treatment achieved complete degradation at 30 minutes of reaction time. On the other hand, it was observed that the degradation was faster by adding H2O2 (H2O2/O3 molar ratio = 0.5). In this case, total degradation was observed after 20 minutes.

scholarly journals DABCO Catalyzed Synthesis of Xanthene Derivatives in Aqueous Media

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Pradeep Paliwal ◽  
Srinivasa Rao Jetti ◽  
Anjna Bhatewara ◽  
Tanuja Kadre ◽  
Shubha Jain
Keyword(s):  
Reaction Time ◽  
Aqueous Media ◽  
Environmentally Friendly ◽  
The Other ◽  
Short Reaction Time ◽  
Xanthene Derivatives ◽  
Reaction Proceeds ◽  
Conventional Methods

The reaction of 5,5-dimethylcyclohexane-1,3-dione with various heteroarylaldehydes afforded the corresponding heteroaryl substituted xanthene derivatives 1(a–f). The reaction proceeds via the initial Knoevenagel, subsequent Michael, and final heterocyclization reactions using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst in aqueous media. The synthesized heteroaryl substituted xanthenes 1(a–f) reacted with malononitrile to obtain different alkylidenes 2(a–f). Short reaction time, environmentally friendly procedure, avoiding of cumbersome apparatus, and excellent yields are the main advantages of this procedure which makes it more economic than the other conventional methods.

scholarly journals Continuous Flow Chlorination of Alkenyl Iodides Promoted by Copper Tubing

Synthesis ◽  
2018 ◽  
Vol 51 (01) ◽  
pp. 251-257 ◽  
Author(s):  
Antoine Nitelet ◽  
Vanessa Kairouz ◽  
Hélène Lebel ◽  
André Charette ◽  
Gwilherm Evano
Keyword(s):  
Reaction Time ◽  
Double Bond ◽  
Continuous Flow ◽  
Batch Process ◽  
Flow Synthesis ◽  
Copper Tubing

A simple continuous flow synthesis of alkenyl chlorides from the corresponding readily available alkenyl iodides in copper reactor tubing is described. A variety of alkenyl chlorides were obtained in good to excellent yields with full retention of the double bond geometry. The reaction time was reduced by a factor of 24–48 compared to the batch process.

scholarly journals Transferrin-Conjugated SNALPs Encapsulating 2′-O-Methylated miR-34a for the Treatment of Multiple Myeloma

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Immacolata Scognamiglio ◽  
Maria Teresa Di Martino ◽  
Virginia Campani ◽  
Antonella Virgilio ◽  
Aldo Galeone ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Zeta Potential ◽  
Lipid Vesicles ◽  
Significant Inhibition ◽  
The Other ◽  
Transferrin Receptors ◽  
Proof Of Concept ◽  
Wild Type ◽  
Chemical Conjugation ◽  
Mean Size

Stable nucleic acid lipid vesicles (SNALPs) encapsulating miR-34a to treat multiple myeloma (MM) were developed. Wild type or completely 2′-O-methylated (OMet) MiR-34a was used in this study. Moreover, SNALPs were conjugated with transferrin (Tf) in order to target MM cells overexpressing transferrin receptors (TfRs). The type of miR-34a chemical backbone did not significantly affect the characteristics of SNALPs in terms of mean size, polydispersity index, and zeta potential, while the encapsulation of an OMet miR-34a resulted in a significant increase of miRNA encapsulation into the SNALPs. On the other hand, the chemical conjugation of SNALPs with Tf resulted in a significant decrease of the zeta potential, while size characteristics and miR-34a encapsulation into SNALPs were not significantly affected. In an experimental model of MM, all the animals treated with SNALPs encapsulating miR-34a showed a significant inhibition of the tumor growth. However, the use of SNALPs conjugated with Tf and encapsulating OMet miR-34a resulted in the highest increase of mice survival. These results may represent the proof of concept for the use of SNALPs encapsulating miR-34a for the treatment of MM.

A Continuous-Flow Model for Phonatory Reaction Time

1991 ◽  
Vol 34 (3) ◽  
pp. 517-525 ◽  
Author(s):  
Carole Ferrand ◽  
Gordon W. Blood ◽  
Harvey R. Gilbert
Keyword(s):  
Reaction Time ◽  
Continuous Flow ◽  
Vocal Fold ◽  
Flow Model ◽  
Reaction Time Task ◽  
Central Process ◽  
Brain Potentials ◽  
Time Task ◽  
Vocal Fold Vibration ◽  
Yield Information

The purpose of this study was to validate a proposed continuous-flow model of phonatory reaction time by investigating the temporal order of selected laryngeal and neurophysiological events involved in a phonatory reaction time task. Ten normal speakers participated in a phonatory reaction time task. Laryngeal positioning movements prior to vocal fold closure (laryngeal shift) and onset of vocal fold vibration (acoustic onset) were recorded with an electroglottograph. P300 brain potentials were collected simultaneously, and they served as an index of a central process underlying reaction time. The obtained temporal ordering of laryngeal shift, P300, and acoustic onset supported a continuous-flow model of phonatory reaction time. Use of this model might yield information that is more accurate in explaining physiological function and more precise in describing temporal patterning than the serial model.

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