Electro-oxidation of waste glycerol to tartronic acid over Pt/CNT nanocatalyst: study of effect of reaction time on product distribution

2019 ◽  
pp. 1-17 ◽  
Author(s):  
Muhammad Sheraz Ahmad ◽  
Chin Kui Cheng ◽  
Huei Ruey Ong ◽  
Hamidah Abdullah ◽  
Chi Shein Hong ◽  
...  
Keyword(s):  
Reaction Time ◽  
Product Distribution ◽  
Waste Glycerol ◽  
Tartronic Acid ◽  
Electro Oxidation

scholarly journals The Effect of Steam and Glycerol Pretreatment on Chemical Contents of Oil Palm Empty Fruit Bunch (EFB)

2018 ◽  
pp. 61-67
Author(s):  
Ornjira Choopakar ◽  
Chongchin Polprasert ◽  
Panagiotis Elefsiniotis ◽  
Supawadee Polprasert
Keyword(s):  
Reaction Time ◽  
Reaction Times ◽  
Steam Pretreatment ◽  
Chemical Components ◽  
Distilled Water ◽  
Waste Glycerol ◽  
Empty Fruit Bunches ◽  
Pretreatment Conditions ◽  
Set Up ◽  
Water Waste

This research aimed to evaluate the effect of the type of solvent, pH, substrate loading, and reaction time on the chemical components of palm empty fruit bunches (EFB). Steam pretreatment was set up at a temperature of 121 °C and pressure of 1.18 bar, using an autoclave with substrate loading of 5, 10, 15 and 20 % w/v at reaction times of 15 and 60 min. Distilled water, waste glycerol, alkaline glycerol and acidic glycerol were compared as solvents during steam pretreatment. The results showed that with distilled water, better pretreatment was achieved at 5 % and 10 % loading for 60 min. During the pretreatment with waste glycerol at 5 % loading an increase on the reaction time from 15 to 60 min reaction resulted in a remarkable increase in reducing sugar in the liquid phase. Overall, the best steam pretreatment conditions were observed using alkaline glycerol at 5 % w/v and 15 min reaction time, resulting in holocellulose (cellulose plus hemicellulose) increase to 87.98 % and a lignin decrease to 9.17 %. However, pretreatment with glycerol for 15 min was better than those for 60 min using either glycerol or distilled water. The results suggest that waste glycerol during steam pretreatment of EFB can be utilized effectively at short reaction times and at an increased pH to achieve a high output of cellulose and hemicellulose for sugar conversion in the bioethanol fermentation process.

Glycerol Waste Valorization to Mesoxalic Acid Over a Bimetallic Pt-Pd/CNT Catalyst in Alkaline Medium

2020 ◽  
Vol 20 (9) ◽  
pp. 5916-5927
Author(s):  
Muhammad Sheraz Ahmad ◽  
Chin Kui Cheng ◽  
Sharanjit Singh ◽  
Huei Ruey Ong ◽  
Hamidah Abdullah ◽  
...  
Keyword(s):  
Alkaline Medium ◽  
High Performance ◽  
Value Added ◽  
Linear Sweep Voltammetry ◽  
Poor Performance ◽  
Oxidation Products ◽  
Glyceric Acid ◽  
Monometallic Catalysts ◽  
Tartronic Acid ◽  
Electro Oxidation

Glycerol electro-oxidation offers a green route to produce the high value added chemicals. Here in, we report the glycerol electro-oxidation over a series of multi walled carbon nano tubes supported monometallic (Pt/CNT and Pd/CNT) and bimetallic (Pt-Pd/CNT) catalysts in alkaline medium. The cyclic voltammetry, linear sweep voltammetry and chronoamperometry measurements were used to evaluate the activity and stability of the catalysts. The Pt-Pd/CNT electrocatalyst exhibited the highest activity in terms of higher current density (129.25 A/m2) and electrochemical surface area (382 m2/g). The glycerol electro-oxidation products formed at a potential of 0.013 V were analyzed systematically by high performance liquid chromatography. Overall, six compounds were found including mesoxalic acid, 1,3-dihydroxyacetone, glyceraldehyde, glyceric acid, tartronic acid and oxalic acid. A highest mesoxalic acid selectivity of 86.42% was obtained for Pt-Pd/CNT catalyst while a maximum tartronic acid selectivity of 50.17% and 46.02% was achieved for Pd/CNT and Pt/CNT respectively. It was found that the introduction of Pd into Pt/CNT lattice facilitated the formation of C3 products in terms of maximum selectivity achieved (86.42%) while the monometallic catalysts (Pd/CNT and Pt/CNT) showed a poor performance in comparison to their counterpart.

Photocatalytic Hydroxylation of Phenol over Ti-Containing Zeolites (TS-1, Ti-MCM-41)

2007 ◽  
Vol 124-126 ◽  
pp. 1793-1796 ◽  
Author(s):  
Gun Dae Lee ◽  
Sung Gab Kim ◽  
Hee Hoon Jeong ◽  
Seong Soo Park ◽  
Seong Soo Hong
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Reaction Time ◽  
Product Distribution ◽  
Thermal Reaction ◽  
Hydroxylation Of Phenol ◽  
In Situ Crystallization ◽  
The Difference ◽  
Mcm 41

The photo-catalytic hydroxylation of phenol with hydrogen peroxide was carried out over TS-1 and Ti-MCM-41 catalysts. For comparison, the dark (thermal)-catalytic hydroxylation of phenol was also performed. The difference in catalytic behaviors of TS-1 and Ti-MCM-41 and product distribution in both the reactions were investigated. The TS-1 and Ti-MCM-41 catalysts having the Si/Ti ratio of 50 were prepared by in-situ crystallization and characterized using XRD, UV-DRS. In the all reactions, the main products were catechol (CAT), hydroquinone (HQ) and benzoquinone (BQ). In dark (thermal)-reaction, TS-1 showed a higher catalytic activity than Ti- MCM-41. In photo-reaction, however, the activity of Ti-MCM-41 was comparable to that of TS-1. The conversion of phenol and the selectivity to CAT in the photo-catalytic reaction were higher than those in dark (thermal)-reaction. In the all reactions, the selectivity to CAT increased remarkably when the selectivities to HQ and BQ decreased with reaction time.

Kinetics of Hydrogenolysis of Glycerol to Ethylene Glycol over Raney Ni Catalyst

2014 ◽  
Vol 906 ◽  
pp. 103-111 ◽  
Author(s):  
Tao Jiang ◽  
Mei Xuan Ren ◽  
Shi Shi Chen ◽  
Qiang Huai ◽  
Wei Yong Ying ◽  
...  
Keyword(s):  
Reaction Time ◽  
Ethylene Glycol ◽  
Batch Reactor ◽  
Rapid Development ◽  
Estimation Method ◽  
Product Distribution ◽  
Biodiesel Production ◽  
Ni Catalyst ◽  
Raney Ni ◽  
Kinetics Of

The rapid development of biodiesel production yields large amount of glycerol as a by-product. It is a resource-utilization efficient and biological technical process to employ hydrogenolysis of glycerol aqueous solution for ethylene glycol generation. In this work, Raney Ni catalyst was prepared through conventional means and tested for hydrogenolysis of glycerol to produce ethylene glycol. The experiments were performed by varying the reaction time and rotate speed at a hydrogen pressure of 6.0-10.0MPa over a temperature range of 453-493K using a batch reactor. The effect of reaction conditions on the conversion of glycerol and the product distribution were also investigated and discussed. The results indicated that with the increase of reaction time the conversion of glycerol and the selectivity of 1,2-PDO tended to rise but the concentration of ethylene glycol decreased after reaching a peak point. The conversion of glycerol reached as much as 100% and the selectivity of ethylene glycol reached a maximum of 40%. Based on the experimental data, the reaction kinetics was studied and the parameters involved a two-site Langmuir-Hinshelwood model were acquired by the parameter estimation method. In the end, residual error distribution and statistic test showed that the obtained kinetic model was suitable and acceptable.

REACTION TIME AND INTELLIGENCE

1991 ◽  
Vol 1 (1) ◽  
pp. 211-221 ◽  
Author(s):  
Edward Neçka
Keyword(s):  
Reaction Time

Modeling Within-Person Variance in Reaction Time Data of Older Adults

GeroPsych ◽  
2011 ◽  
Vol 24 (4) ◽  
pp. 169-176 ◽  
Author(s):  
Philippe Rast ◽  
Daniel Zimprich
Keyword(s):  
Reaction Time ◽  
Cognitive Aging ◽  
Reaction Times ◽  
Reaction Time Task ◽  
Reaction Time Data ◽  
Scale Model ◽  
Time Data ◽  
Time Task ◽  
The Mean ◽  
Second Wave

In order to model within-person (WP) variance in a reaction time task, we applied a mixed location scale model using 335 participants from the second wave of the Zurich Longitudinal Study on Cognitive Aging. The age of the respondents and the performance in another reaction time task were used to explain individual differences in the WP variance. To account for larger variances due to slower reaction times, we also used the average of the predicted individual reaction time (RT) as a predictor for the WP variability. Here, the WP variability was a function of the mean. At the same time, older participants were more variable and those with better performance in another RT task were more consistent in their responses.

The Level of Reaction Time Determines the ERP Correlates of Auditory Negative Priming

2006 ◽  
Vol 20 (3) ◽  
pp. 186-194 ◽  
Author(s):  
Susanne Mayr ◽  
Michael Niedeggen ◽  
Axel Buchner ◽  
Guido Orgs
Keyword(s):  
Reaction Time ◽  
Negative Priming ◽  
Effect Size ◽  
Priming Effect ◽  
Reaction Times ◽  
Negative Priming Effect ◽  
Episodic Retrieval ◽  
Time Level ◽  
Fast Reactions ◽  
Priming Condition

Responding to a stimulus that had to be ignored previously is usually slowed-down (negative priming effect). This study investigates the reaction time and ERP effects of the negative priming phenomenon in the auditory domain. Thirty participants had to categorize sounds as musical instruments or animal voices. Reaction times were slowed-down in the negative priming condition relative to two control conditions. This effect was stronger for slow reactions (above intraindividual median) than for fast reactions (below intraindividual median). ERP analysis revealed a parietally located negativity of the negative priming condition compared to the control conditions between 550-730 ms poststimulus. This replicates the findings of Mayr, Niedeggen, Buchner, and Pietrowsky (2003) . The ERP correlate was more pronounced for slow trials (above intraindividual median) than for fast trials (below intraindividual median). The dependency of the negative priming effect size on the reaction time level found in the reaction time analysis as well as in the ERP analysis is consistent with both the inhibition as well as the episodic retrieval account of negative priming. A methodological artifact explanation of this effect-size dependency is discussed and discarded.

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