Cavitation-induced Reactions in Pure Substituted Benzenes

1972 ◽  
Vol 50 (11) ◽  
pp. 1743-1750 ◽  
Author(s):  
G. K. Diedrich ◽  
P. Kruus ◽  
L. M. Rachlis
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Cavitation Bubble ◽  
Reaction Rate ◽  
Substituted Benzenes ◽  
Thermal Reactions ◽  
Initiation Reaction ◽  
Low Temperature Pyrolysis

The formation of polymers has been observed on exposure of pure substituted benzenes to ultrasound intense enough to cause cavitation. The products have some of the characteristics of the char obtained from low temperature pyrolysis of hydrocarbons. They are difficult to dissolve, melt above 300 °C, and give a large broad e.p.r. signal. A crude correlation between bond dissociation energy and the reaction rate suggests that the initiation reaction is a thermal decomposition in a cavitation bubble. The phenomenon is compared to radiolysis and thermal reactions.

Reactivity of Peroxyl Radicals towards Hydrogen Donors: A Kinetic ESR Investigation

2009 ◽  
Vol 12 (2) ◽  
Author(s):  
A. Criqui ◽  
J. Lalevée ◽  
X. Allonas ◽  
J. P. Fouassier
Keyword(s):  
Bond Dissociation Energy ◽  
Dissociation Energy ◽  
Rate Constants ◽  
Reaction Rate ◽  
Peroxyl Radicals ◽  
Efficient Technique ◽  
Reaction Rate Constants ◽  
Hydrogen Donors

AbstractPeroxyl radicals are usually assumed as key intermediates in oxidation or autoxidation processes rendering important a better understanding of their associated reactivity. Kinetic ESR is proposed here as an efficient technique for the determination of their reaction rate constants. The interactions between peroxyl radicals and a large variety of hydrogen donors Y-H are reported. The role of the Y-H bond dissociation energy is outlined.

scholarly journals The Effect of Biochar Addition on the Biogas Production Kinetics from the Anaerobic Digestion of Brewers’ Spent Grain

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1518 ◽  
Author(s):  
Dudek ◽  
Świechowski ◽  
Manczarski ◽  
Koziel ◽  
Białowiec
Keyword(s):  
Low Temperature ◽  
Production Rate ◽  
Rate Constant ◽  
Reaction Rate ◽  
Biogas Production ◽  
Reaction Rate Constant ◽  
Waste To Energy ◽  
Biogas Yield ◽  
Spent Grain ◽  
Low Temperature Pyrolysis

Biochar (BC) addition is a novel and promising method for biogas yield increase. Brewer’s spent grain (BSG) is an abundant organic waste with a large potential for biogas production. In this research, for the first time, we test the feasibility of increasing biogas yield and rate from BSG digestion by adding BC, which was produced from BSG via torrefaction (low-temperature pyrolysis). Furthermore, we explore the digestion of BSG with the presence BCs produced from BSG via torrefaction (low-temperature pyrolysis). The proposed approach creates two alternative waste-to-energy and waste-to-carbon type utilization pathways for BSG: (1) digestion of BSG waste to produce biogas and (2) torrefaction of BSG to produce BC used for digestion. Torrefaction extended the short utility lifetime of BSG waste turned into BC. BSG was digested in the presence of BC with BC to BSG + BC weight ratio from 0 to 50%. The study was conducted during 21 days under mesophilic conditions in n = 3 trials. The content of dry mass 17.6% in all variants was constant. The kinetics results for pure BSG (0% BC) were: reaction rate constant (k) 1.535 d−1, maximum production of biogas (B0) 92.3 dm3∙kg−1d.o.m. (d.o.m. = dry organic matter), and biogas production rate (r), 103.1 dm3∙kg−1d.o.m.∙d−1. his preliminary research showed that the highest (p < 0.05) r, 227 dm3∙kg−1d.o.m.∙d−1 was due to the 5% BC addition. This production rate was significantly higher (p < 0.05) compared with all other treatments (0, 1, 3, 8, 10, 20, 30, and 50% BC dose). Due to the high variability observed between replicates, no significant differences could be detected between all the assays amended with BC and the variant 0% BC. However, a significant decrease of B0 from 85.1 to 61.0 dm3∙kg−1d.o.m. in variants with the high biochar addition (20–50% BC) was observed in relation to 5% BC (122 dm3∙kg−1d.o.m.), suggesting that BC overdose inhibits biogas production from the BSG + BC mixture. The reaction rate constant (k) was not improved by BC, and the addition of 10% and 20% BC even decreased k relatively to the 0% variant. A significant decrease of k was also observed for the doses of 10%, 20%, and 30% when compared with the 5% BC (1.89 d−1) assays.

Low-temperature pyrolysis. II. An isotope study of the pyrolysis of the hydrogen phthalate ester of trans-1,2-dimethylcyclohexanol

1967 ◽  
Vol 45 (7) ◽  
pp. 679-681
Author(s):  
K. G. Rutherford ◽  
R. M. Ottenbrite
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Phthalic Anhydride ◽  
Ion Pair ◽  
Phthalate Ester ◽  
Hydrogen Phthalate ◽  
Isotope Study ◽  
Sterically Hindered ◽  
Low Temperature Pyrolysis

The hydrogen phthalate ester of trans-l,2-dimethylcyclohexanol was prepared by using phthalic anhydride enriched in 18O. The ester was partially decomposed at 128°. An observed enrichment of 18O in the alcohol portion of the undecomposed ester supports an earlier postulate that an ion pair is involved in the thermal decomposition of this sterically hindered ester.

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Chemical yields from low-temperature pyrolysis of CCA-treated wood

2009 ◽  
Author(s):  
Qirong Fu ◽  
Dimitris Argyropolous ◽  
Lucian Lucia ◽  
David Tilotta ◽  
Stan Lebow
Keyword(s):  
Low Temperature ◽  
Treated Wood ◽  
Low Temperature Pyrolysis

Preparation of Organic/Inorganic Membrane by PDMS Low-temperature Pyrolysis

2014 ◽  
Vol 29 (2) ◽  
pp. 137-142
Author(s):  
Jiao-Zhu YU ◽  
Lin LI ◽  
Xin JIN ◽  
Ling-Hua DING ◽  
Tong-Hua WANG
Keyword(s):  
Low Temperature ◽  
Inorganic Membrane ◽  
Low Temperature Pyrolysis

scholarly journals Advances in Cryochemistry: Mechanisms, Reactions and Applications

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 750
Author(s):  
Lu-Yan An ◽  
Zhen Dai ◽  
Bin Di ◽  
Li-Li Xu
Keyword(s):  
Low Temperature ◽  
Chemical Reactions ◽  
Common Sense ◽  
Reaction Rate ◽  
Concentration Effect ◽  
Biological Products ◽  
Freeze Concentration ◽  
New Strategy ◽  
The 1960S

It is counterintuitive that chemical reactions can be accelerated by freezing, but this amazing phenomenon was discovered as early as the 1960s. In frozen systems, the increase in reaction rate is caused by various mechanisms and the freeze concentration effect is the main reason for the observed acceleration. Some accelerated reactions have great application value in the chemistry synthesis and environmental fields; at the same time, certain reactions accelerated at low temperature during the storage of food, medicine, and biological products should cause concern. The study of reactions accelerated by freezing will overturn common sense and provide a new strategy for researchers in the chemistry field. In this review, we mainly introduce various mechanisms for accelerating reactions induced by freezing and summarize a variety of accelerated cryochemical reactions and their applications.

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