THE KINETICS OF SELECTIVE HYDRAZINOLYSIS OF MALEIC ACID ON THE ACID CATALYST

For the first time, kinetics and the mechanism of the reaction of hydrazinolysis of maleic acid in the presence of cation exchanger resin KU-2-8 in H-form have been studied. The experiments were carried out in a static system in a thermostat glass reactor. It was found that cation exchanger shows high catalytic activity in the studied process - maleic acid conversion was 93%, and maleic hydrazide yield was 90%. The conversion selectivity of maleic acid to maleic hydrazide was 97,8%. The reaction rate was determined from the accumulation of maleic hydrazide. The apparent reaction rate constant (k) was calculated from the second-order reaction rate equation. The effect of initial concentrations of maleic acid and hydrazine hydrate, the temperature on the reaction rate was studied. The first order of maleic acid and hydrazine hydrate is determined. Activation energy of the process found from the Arrhenius dependence is 32,1 kJ/mol. On the basis of kinetic and IR spectroscopic methods, a probable reaction mechanism involving polymer-bound hydrogen ions is proposed.

Synthesis, Characterization and Pyrolysis Kinetics of Chitosan-N-Phenylacetamide in an Ionic Liquid 1-Butyl-3-Methylimidazolium Chloride

This study intends to synthesis novel compound phenolic chitosan-based via reaction of chitosan with 2-Chloro-N-phenylacetamide in 1-butyl-3-methylimidazolium chloride ionic liquid in the presence of pyridine at 80 °C for 4 h. The alterations in the chemical structure and morphology of the chitosan-N-phenylacetamide biopolymer were verified using IR spectroscopy, XRD, and SEM analyses. Chitosan and Chitosan-N-phenyacetamide were subjected to thermo-gravimetric analysis under an inert atmosphere in the temperature range of room temperature - 600 °C at a heating rate of 20 °C.min-1. The kinetic parameters were determined by the Coats-Redfern method. The corresponding kinetic parameters of the main degradation stages were also determined. The energy required for the degradation of pure chitosan was lower than that of chitosan-N-phenylacetamide in the first region of thermal degradation where the main pyrolysis reaction took place, and the largest weight loss occurred. Energy values in this region are running from 40.25 to 151.07 kJ/mol and 58.45 to 210.99 kJ/mol, respectively. The most probable reaction functions have thus been determined for these two stages by Coats-Redfern and Criado method, leading to greatly improved calculation performance over the entire conversion range. The pyrolysis reaction models of both pure chitosan and chitosan-N-phenylacetamide are described by the reaction, second-order F2.

Hydrodesulfurization of benzothiophene on Ni2P surface

The study of benzothiophene hydrodesulfurization reaction path contribute to clarifying the mechanism of hydrodesulfurization (HDS) of heavy oil. In this work, experiments and simulations were combined to study the reaction pathway of benzothiophene hydrodesulfurization catalyzed by Ni2P. In experimental part, Ni2P catalyst was prepared and characterized. Then, the catalytic property of the catalyst for benzothiophene hydrodesulfurization was evaluated. The substance types and contents in the liquid phase products were detected to verify the accuracy of the simulation results. Dmol3 module of the Materials Studio (MS) simulation software was used to simulate the adsorption and hydrodesulfurization of benzothiophene on the surface of Ni2P catalyst and explore the most probable reaction path. The results showed that the most stable adsorption configuration of benzothiophene on the surface of Ni2P was Ni-hcp. In addition, indirect desulfurization of benzothiophene was more advantageous than direct desulfurization. The most possible path for indirect desulfurization was Benzothiophene (BT) – Dihydrobenzothiophene (DHBT) – C8H9S2 – 2-phenylethyl mercaptan (PET) – Ethylbenzene (EB), while that of direct desulfurization was Benzothiophene (BT) – C8H7S2 – Styrene thiol (CMT) – Styrene (ST) – Ethylbenzene (EB).

An Efficient Strategy for the Synthesis of 1,6-Naphthyridine-2,5-dione Derivatives under Ultrasound Irradiation

A flexible and efficient three-component reaction has been established for the synthesis of bioactive 1,6-naphthyridine-2,5-diones by using low-cost and readily accessible aminopyridinones, aromatic aldehydes, and Meldrum’s acid as starting materials. The main advantage of this synthetic method is that the yields of the resulting 1,6-naphthyridine-2,5-dione derivatives under ultrasound irradiation in water with acetic acid as catalyst are higher than those from the classical-heating method. The probable reaction mechanism indicates that the process involves a Knoevenagel condensation, Michael addition, and cyclization sequence.

Mechanism and Kinetics of Dehydroxylation and Decarbonation of Mg–Fe Hydrotalcite

Thermal behavior of hydrotalcites, which is a calcination process, is critical to prepare the metal oxide catalysts with high performances in the practical applications. In this paper, the MgFe-LDH with Mg/Fe molar ratio of 3.0 was prepared by urea method and the calcined products are obtained by calcining at different temperatures (473 K, 573 K, 673 K, 773 K, 873 K and 973 K) under a N2 atmosphere for 4 h. The structure, morphology, texture, pyrolysis kinetics and mechanism of the MgFe-LDH were studied in detail. On one hand, based on the TG/DSC curves, Starink, Kissinger and Flynn-Wall-Ozawa (FWO) methods were used to calculate the activation energy, on the other hand, the Šatava-Šesták, Achar and Málek methods were used to define the most probable reaction mechanisms of pyrolysis behavior. The results suggested that the thermal decomposition of the LDH experienced two steps, i.e., removal of the interlayer water, followed by dehydroxylation and decarbonation. Moreover the Mákel method was used to define the most probable reaction mechanisms of the pyrolysis behavior.

Facile Synthesis of SnO2/LaFeO3−XNX Composite: Photocatalytic Activity and Gas Sensing Performance

Here SnO2/LaFeO3−XNX composite was fabricated using a wet chemical method and was applied to pollutants degradation and gas sensing for the first time. The composite exhibits high performance for photocatalytic degradation of Rhodamine B (RhB) dye and selectivity sensing of various gases. On the basis of the completed experiments, the improved RhB degradation and selective gas sensing performance resulted from the extended optical absorption via N2 incorporated surface states and enhanced charge separation via coupling SnO2. Using the scavengers trapping experiments, the superoxide radical (O2•−) was investigated as the major scavenger involved in the degradation of RhB over SnO2/LaFeO3−XNX composite. In this paper, the probable reaction steps involved in the RhB dye degradation over SnO2/LaFeO3−XNX composite are proposed. This work will provide reasonable strategies to fabricate LaFeO3-based proficient and stable catalysts for environmental purification. In addition, the result of the selectivity of gas performance is also presented.

Effect of Co-precursor Maliec Anhydride on the Thermal Decomposition of Acetyl Ferrocene: A Reaction Kinetic Analysis

Background: Thermal decomposition of iron-bearing organometallic complex acetyl ferrocene, (C5H4COCH3)Fe(C5H5), leads to hematite (α-Fe2O3) nanoparticles. Presence of maliec anhydride, C4H2O3 as co-precursor during thermal decomposition modifies the size of the particles as well as the quantity of the reaction product significantly. Objective: Kinetic analysis of the solid-state thermal reaction of acetyl ferrocene in the presence of varying amount of co-precursor maliec anhydride under inert reaction atmosphere has been studied in order to understand the reaction mechanism involved behind the formation of hematite and the role of co-precursor in the reaction process. For this purpose, reaction kinetic analysis of three mixtures of acetyl ferrocene and maliec anhydride has been carried out. Methods: Thermogravimetry under non-isothermal protocol with multiple heating rates has been employed. The data are analyzed using model-free iso-conversional kinetic techniques to estimate the activation energy of reaction and reaction rate. The most-probable reaction mechanism has been identified by master plot method. The kinetic triplets (activation energy, reaction rate, most probable reaction mechanism function) have been employed to estimate the thermodynamic triplets (ΔS, ΔH and ΔG). Observations: Acetyl Ferrocene (AFc) undergoes thermal decomposition in a four-step process leaving certain residual mass whereas maliec anhydride (MA) undergoes complete mass loss owing to melting followed by evaporation. In contrast, the (AFc1-x-MAx) mixtures undergo thermal decomposition through a two-step process, and the decompositions are completed at much lower temperatures than that in AFc. The estimated activation energy and reaction rate values are found strongly dependent on the extent of conversion as well as on the extent of mixing. Introduction of MA in the solid reaction atmosphere of AFc in one hand reduces the activation energy required by AFc to undergo thermal decomposition and the reaction rate, while on the other hand varies the nature of reaction mechanism involved. Results: The range of reaction rate values estimated for the mixtures indicate that the activated complexes during Step-I of thermal decomposition may be treated as ‘loose’ complex whereas ‘tight’ complex for the Step-II. From the estimated entropy values, thermal process of (AFc1-x-MAx) mixture for Steps I and II may be interpreted as ‘‘slow’’ stage. Conclusion: Variation of Gibb’s free energy with the fraction of maliec anhydride in the mixtures for Step-I and II indicate that the thermal processes of changing the corresponding activated complexes are non-spontaneous at room temperature.

The Master Key to the Problem of Reversible Chemical Hydrogen Storage and Reversible Energy Storage Alike is 12 kJ (mol H2)-1

<div>This article outlines a potent theoretical formalism illuminating the boundaries to reversible solid hydrogen storage based on the ideal gas law and classic equilibrium thermodynamics. A global picture of chemical reversible hydrogen sorption is unveiled including a thermodynamic explanation of partial reversibility. This is utilized to elucidate a multitude of issues from metal hydride chemistry (as ESI): Highlights are explanations why the substitution of a mere 4 mol % Na by K in Ti-doped NaAlH₄ raises the reversible storage capacity by 42 % and elaboration of the utmost probable reaction pathway in (Rb/K)H-doped Mg(NH₂)₂/2LiH. The ESI further contains a demonstration of relevance to electrochemistry by means of the NAS-battery cell, concisely predicting the starting point of the cell voltage drop where experiment shows it to be. The findings of this work allow for a change of paradigm towards the understanding of reversible chemical energy storage and provide a hitherto sorely missing tool of tremendous analytic and predictive power, complementary to experiment.</div>

The Key to the Problem of Reversible Chemical Hydrogen Storage and Reversible Energy Storage Alike is 12 kJ (mol H2)-1

<div>This article outlines a potent theoretical formalism illuminating the boundaries to reversible solid hydrogen storage based on the ideal gas law and classic equilibrium thermodynamics. A global picture of chemical reversible hydrogen sorption is unveiled including a thermodynamic explanation of partial reversibility. This is utilized to elucidate a multitude of issues from metal hydride chemistry (as ESI): Highlights are explanations why the substitution of a mere 4 mol % Na by K in Ti-doped NaAlH₄ raises the reversible storage capacity by 42 % and elaboration of the utmost probable reaction pathway in (Rb/K)H-doped Mg(NH₂)₂/2LiH. The ESI further contains a demonstration of relevance to electrochemistry by means of the NAS-battery cell, concisely predicting the starting point of the cell voltage drop where experiment shows it to be. The findings of this work allow for a change of paradigm towards the understanding of reversible chemical energy storage and provide a hitherto sorely missing tool of tremendous analytic and predictive power, complementary to experiment.</div>

REALIZATION OF THE RIGHT OF REBELLION: FROM THE MANIFESTATION OF DEMOCRACY TO A CRIME AGAINST THE STATE

The objective of the article is to identify, describe, and explain the grounds and conditions for realizing the right of rebellion, delimitation of the relevant democratic procedures from anti-state crimes. The main results of the research are that we have established the liberal and democratic principles for the realization of the right of rebellion. It has been established that it can be realized only on the grounds of the extreme necessity in restoring the rule of law, that is, while having an exclusively criminal and preventive purpose. We have also discovered that both a democratic procedure of realizing the right of rebellion can be solely considered on condition of sufficient justification, proof of the long ineffectiveness of other means of influencing the criminalized apparatus of the state, in particular judicial ones. It has been substantiated that the essential condition for the realization of such a right is the critical level of nonconfidence to the personnel of the highest agencies of state power in the overwhelming majority of the population, as well as the actual impossibility to apply (implement) the statutory forms of influence on their personnel. It is mandatory to consider the requirement of ensuring national security on the basis of a scientifically grounded criminological forecast of the deployment of mass resistance, taking into account the probable reaction to it by the subjects of international law. Thus, the realization of the right of rebellion should be non-violent. In all other cases, there is a criminal seizure of state power. The applied value of the research is the fact that due to the developed system of grounds and conditions for realizing the right of rebellion, the latter, as it is, may be delimitated from political criminal practices aimed at dismantlement of the Constitutional statehood, the seizure of state power. The results of the research may also be taken into account by political actors, as well as law enforcement agencies, courts while criminological substantiation, prediction of mass resistance measures, and legal assessment of such actions. Value/originality. The authors of the work have improved the criminological vision of the movement of mass resistance, which can take place both in the form of the realization of the natural right of rebellion and in the form of anti-state crimes. The use of these developments can be useful in the retrospective legal assessment of the situation of mass protests, forms, means, and consequences of responding to them by the authorities, preventing abuse of the right of rebellion and related crimes.