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A novel carbazole compound, named 1-(9-ethyl-9H-carbazol-3-yl)-3-phenylurea (Cpu) was synthesized and its binding properties with protease enzymes (pepsin and trypsin) has been examined by steady-state fluorescence measurements, UV/vis absorption, infrared (FT-IR) and circular dicroism (CD) spectroscopies and also computational methods. The fluorescence experimental results indicated that the quenching mechanism of enzyme by Cpu is static process. The thermodynamic parameters (both negative ΔH/ΔS) and molecular docking results suggested that the binding of Cpu to pepsin/trypsin were driven by hydrogen bonds and van der Waals forces. Based on Förster's theory, the binding distance (r) between pepsin/trypsin and Cpu was calculated to be 3.072/2.784 nm, which implies that non-radiative energy transfer occurs from enzyme to Cpu. Furthermore, absorption, CD, and FT-IR spectral analysis provided an evidence that the presence of Cpu induced notable changes in the secondary structures and microenvironmental of both pepsin and trypsin, supporting its significant influence on these enzymes. [ABSTRACT FROM AUTHOR]

A kinetic-spectrophotometric method has been devised to analyze the oxidation reaction of Para-aminobenzyl alcohol [PABAlc] catalyzed by Ag (I). PABAlc is used in numerous fields of pharmaceutical and medicinal chemistry as intermediates. The harmful effects of PABAlc cannot be overlooked in spite of its manifold applications. The toxicity of PABAlc may lead to allergic reactions, serious eye damage, respiratory tract infections amongst few. It became utmost important to formulate a method to establish the presence of PABAlc in a particular sample of water in order to circumvent its proximity to common people. In our work, we have provided an insight to an oxidation process using PABAlc as substrate catalyzed by Ag (I) ions besides proposing a reaction mechanism of the reaction under study with substantial data in the form of different thermodynamic parameters like activation energy (55 kJ/mol−1), temperature coefficient (1.92), enthalpy of activation (52.89 kJ/mol−1), alongside deets related to various effects of oxidant, substrate, catalyst, temperature, pH, ionic strength, and so on, on reaction kinetics. Additionally, the product formed in the proposed mechanism has its commercial importance in the field of pharmacy, dyes, and so on, sufficient enough to put forward a rationale for the investigations. [ABSTRACT FROM AUTHOR]

Due to the widespread use of lithium-ion batteries, evaluations of the flammability and explosive characteristics of carbon dust materials as anodes require attention. Carbon dust often reaches the micron/nano scale, and dust particle state and explosion risk generated in different industrial scenarios are different, which is in urgent need of research. Nanoscale dust has relatively static coagulation properties and shows characteristics of dispersion and reagglomeration under a certain airflow. The particle size characteristics affect its thermodynamic characteristics and various consequence parameters of dust explosion. The oxidation and combustion characteristics are mainly affected by dust particle size distribution characteristics. The apparent activation energy is mainly affected by the proportion of small and medium-sized particles and pre-exponential index factor is mainly affected by the dust overall average particle size and specific surface area. The explosion consequence parameters are affected by the thermodynamic parameters, by the disturbance state, particle distribution degree of dust cloud and other factors, which affect the heat radiation and heat transfer process to some extent resulting in different explosion consequence parameters. Due to the agglomeration characteristics of nano-level dust, the minimum ignition energy and minimum ignition temperature of nano-level dust are generally smaller than that of micron level dust. [ABSTRACT FROM AUTHOR]

Polymethylmethacrylate, PMMA, with sponge or finger pores are interesting depending on the application. Our goal was to investigate parameters (Φ and Φ') to foresee the morphology of PMMA prepared by phase inversion based on chemical composition (amount and type of solvent, non-solvent and surfactant). A literature survey was conducted with different chemical composition and analyzed by statistical tools. Sponge-like structures were obtained in systems whose Φ value is less than 0.22 or the Φ' value is more than 0.55. Both indexes can differentiate to some extent systems that generate finger-like structures from those that generate sponge-like ones. [ABSTRACT FROM AUTHOR]

In this study, the effects of Cu addition on AlFeMnTiSi0.75Cux (x = 0, 0.25, 0.5, 0.75, 1.00; in molar ratios) high entropy alloys (HEAs) prepared via mechanical alloying and spark plasma sintering were investigated. The structure, phase, morphology and composition of HEA powders were analysed and the results revealed that the AlFeMnTiSi0.75Cux HEAs exhibited a multiphase structure. Additionally, after sintering at 900 °C, the formation of BCC, µ and L21 phases in the densified HEAs was enhanced. The investigation of the hardness, nanoindentation and compressive properties revealed that the microstructural and mechanical properties of AlFeMnTiSi0.75Cux HEAs were improved at the optimal Cu fraction (0.25 molar ratio). The nanoindentation results revealed that the AlFeMnTiSi0.75Cux HEAs exhibited the highest hardness and elastic modulus (HIT = 19.2 GPa, EIT = 336 GPa). These results improve the current understanding of multiphase HEAs and may pave way for the development of advanced HEAs with superior mechanical properties. [ABSTRACT FROM AUTHOR]

Iodometric analysis is used to determine the kinetics and mechanism of oxidation of benzoic, m-amino, and m-nitro benzoic acid hydrazides by Thallium(III) in acidic medium at constant ionic strength. The complex decomposes to produce the product. The rate of the reaction is decreased by the rise in [H+] and [Cl-]. Additionally, Activation parameters were established, and a mechanism is proposed. The analysis of reaction constants (σ) and substituent constants (s) for m-nitro BAH and m-amino BAH indicates good agreement with the values from the literature. [ABSTRACT FROM AUTHOR]

Biomass syngas can be considered as a supplementary fuel to partially substitute coal, which is beneficial to CO2 emission reduction. For the case study, the influences of co-firing typical biomass syngas (gasification from palm, straw, and wood) with coal on the thermodynamic parameters of a 300 MW tangentially fired boiler are evaluated through a thermal calculation based on the principles of mass conservation, heat conservation, and heat transfer. The effects of boiler loads, biomass syngas species, and consumption rates are discussed. The results show that the introduction of biomass syngas weakens the radiative characteristics of the flame and reduces the furnace exit flue-gas temperature. As 3 × 104 m3 h−1 of wood syngas is introduced, the decrement of thermal efficiency reaches 0.4%, while that of the coal consumption rate is 5.1%. The retrofitting of the boiler was not necessary and the corrosion of the low-temperature heating surface did not appear. The CO2 annual emission reduction could achieve 0.001 to 0.095 million tons for palm syngas, 0.005 to 0.069 million tons for straw syngas, and 0.013 to 0.107 million tons for wood syngas with increasing biomass syngas consumption rates under the full load. Moreover, the main thermodynamic parameters changed more significantly under the low loads. [ABSTRACT FROM AUTHOR]

The work mentioned in the title of this comments-typed paper contains several calculations that disagree with some basic chemistry concepts. These misleading calculations mainly include (i) both kinetic and isotherm modeling through linear equations and (ii) calculating the thermodynamic parameters for the adsorption processes. Thus, we remind how to correct ways allowing to make these calculations. In our opinion, it is a source of confusion for the scientific community to continue using inappropriate methods as applied in the original paper. [ABSTRACT FROM AUTHOR]

Objective: Hydroxypropyl-β-cyclodextrin (HP-β-CD)/menthyl acetate (MA) microcapsules were developed to overcome the volatile and unstable defects of MA and improve the ease of use and storage. Methods: MA microcapsules were prepared via spray drying using HP-β-CD as the wall material. The embedding rate of MA microcapsules was determined through gas chromatography. The embedding characteristics were studied using phase solubility and nuclear magnetic resonance (NMR). The stability was characterized via differential scanning calorimetry (DSC) and the release and retention rates of MA microcapsules at different temperatures. Results: The embedding rate of HP-β-CD /MA microcapsules was 96.3%. The Gibbs free energy change, enthalpy change and entropy change of the embedding reaction between HP-β-CD and MA were all less than zero, indicating that the embedding process was a spontaneous exothermic reaction. NMR spectra showed that MA entered the cavity of HP-β-CD through the large opening end and interacted with the inner wall of the small opening end. DSC and the release and retention rates of MA microcapsules at different temperatures showed that the stability of MA was significantly enhanced after being embedded in HP-β-CD. Conclusion: The HP-β-CD/MA microcapsules are able to significantly improve the stability of MA and reduce the volatilization of MA. [ABSTRACT FROM AUTHOR]

Bamboo is abundantly available in India, particularly in the North East regions which can provide a significant energy opportunity in this region. The physicochemical and thermal properties of bamboo species originate from different places are distinct. This study investigates the pyrolysis of 20 different bamboo species from North East regions of India in a thermogravimetric analyser (TGA) at four different heating rates of 10, 20, 30, and 40 K/min. Enormous kinetic and thermodynamic data are presented for 20 varieties of bamboo species. Model‐free kinetic methods are used to calculate the kinetic parameters and their values are compared. The average activation energy of all bamboo species is estimated in the range 145.59–219.15 kJ/mol from the Starink method, the method recommended by International Confederation of Thermal Analysis and Calorimetry (ICTAC). Generalized master plot method is used for the determination of reaction mechanism which reveals that most of the bamboo species follow the second‐order reaction model (F2) during their thermal degradation. The thermodynamic parameters reveal that the pyrolysis process of all bamboo species is endothermic and it reaches near to the thermodynamic equilibrium. [ABSTRACT FROM AUTHOR]

The impact of different concentrations of sodium carboxymethyl cellulose (NaCMC) on the micellization process in cationic, ester-functionalized, ethyl-substituted imidazolium-based surface-active ionic liquids (SAILs) ([CnEeim]Br where, n = 12, 14, 16) were investigated using specific conductivity and surface tension measurements at 298 K. The study focused on determining the critical micelle concentration (CMC) of the three pure SAILs and their mixtures with NaCMC to evaluate various thermodynamic and interfacial parameters. The results showed that the CMC values decreased significantly with increasing hydrophobicity of the SAILs, while the CMC increased with a gradual increase in the NaCMC mole fraction in the SAIL–NaCMC mixed systems. It was observed that the excess free energy of micellization ( ∆ G e x m ) and the minimum free energy of surface at equilibrium ( ∆ G min s ) exhibited an opposite behaviour, indicating that the formed mixed micelles were stable while the formed surface was unstable. The results of this study are useful for evaluating the properties of SAIL–NaCMC mixed systems to improve and better understand their applications in the food, medical and cosmetic industries. [ABSTRACT FROM AUTHOR]

The detonation propagation characteristics of the mixtures, 2H 2 + O 2 +3Ar and CH 4 + 2O 2 , were investigated. Accordingly, the mixtures were tested in round tube with inner diameter of D = 80 mm and annular tubes with widths of w = 25 mm, 15 mm, and 5 mm. The two mixtures represent stable mixture with regular cell pattern and unstable mixture with irregular cell pattern, respectively. Smoked foils were utilized to record cellular structure under various initial conditions. Subsequently, the length scale L dsc was measured, which represents the length from the start of the test section to the position where the cellular structure changes drastically (the cell size obviously increases or the structure disappears). The results reveal that both mixtures can successfully propagate in round tube and annular tubes of 25 mm and 15 mm, but fail in 5 mm annular tube. The L dsc value of 2H 2 + O 2 + 3Ar is higher than that of CH 4 + 2O 2 in 80 mm and 15 mm tubes, but it is opposite in 25 mm tube. Moreover, the relationship between L dsc and hydraulic diameter D H was analysed. For a given tube, the values of L dsc and L dsc / D H increased when the initial pressure increased. And the variation trend of L dsc and L dsc / D H of CH 4 + 2O 2 is steeper. Furthermore, the mixtures 2H 2 + O 2 + 3Ar and CH 4 + 2O 2 resulted in over-driven detonation in 15 mm and 25 mm annular tubes, respectively. The ratio between the total reaction length (sum of the induction length and exothermic length) and the hydraulic diameter (D H /(Δ i + Δ e)) correspond to critical values of 18 for hydrogen-oxygen-argon and 6 for methane-oxygen, below which the detonation will fail. [ABSTRACT FROM AUTHOR]

The Radke–Prausnitz model, a typical three-parameter model belonging to the Langmuir–Freundlich-type equation, is increasingly being used to correlate the equilibrium data of various adsorption processes. However, very few published works provide the correct information on (1) the nonlinear form of this model, (2) the units of its parameters, and (3) its original citation. This work provides a critical analysis of the Radke–Prausnitz model with special emphasis on promoting its proper application in adsorption research. The correct expression and citation of the models used in adsorption studies are provided. The correct units of its parameters aRP , bRP , and β are L/kg , (mol/kg)/(mol/L)β , and unitless when the solution phase concentration Ce is given in mol/L and the adsorbed phase concentration qe is defined in mol/kg. The Radke–Prausnitz model can be reduced to the Henry, Freundlich, Langmuir, or Redlich–Peterson model in some special cases. The Radke—Prausnitz model is valid when the exponent β is in the range of 0≤β≤1. A new adsorption equilibrium constant of this model is introduced. The feasibility of using the new equilibrium constant to calculate the thermodynamic parameters (ΔG° , ΔH° , and ΔS°) of adsorption processes is discussed herein. [ABSTRACT FROM AUTHOR]

Context: Using chemical penetration enhancers to improve the penetration effect is one kind of important strategies in transdermal drug delivery system. Azone is a widely used transdermal absorption enhancer for transdermal drug delivery. To shed light on the permeation-promoting mechanism of azone, we selected ternary systems formed by azacyclopentane-2-one and N-methylolacetamide (1: 2) and explored the synergetic effect of hydrogen-bonding interactions among them and their thermodynamic properties. The findings indicate that the synergetic effects can enhance the ability of azone to change the original conformation of ceramides and even break the original hydrogen bonds, which is more beneficial for azone to destroy the 3D network structure of ceramides. When azone interacts with ceramide, the order of action tends to interact with one molecule of ceramide first and then with another molecule of ceramide. Methods: The synergetic effects of hydrogen-bonding interactions in ternary systems were computed at the B3LYP/6–311 + + G** and MP2(full)/6–311 + + G** levels. Thermodynamic parameters for two ternary-complex routes were worked out at the B3LYP/aug-cc-pVDZ level. The shift of the electron density occurring simultaneously with trimer formation was analyzed at the MP2(full)/6–311 + + G** level. The above calculations were carried out using the Gaussian 03 program packages. Atoms in molecules (AIM) method and the AIMPAC program showed the topological charge density at the MP2(full)/6–311 + + G** level. The synergetic effects of hydrogen-bonding interactions and thermodynamic property in the 1: 2 (azacyclopentane-2-one: N-methylolacetamide) ternary systems were investigated using the B3LYP and MP2(full) methods [ABSTRACT FROM AUTHOR]

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• The micellization parameters (CMC and α) of synthesized surfactant (12-2-O-2-12) were determined by conductometric method. • Standard Gibbs free energy, Δ G m o and enthalpy, Δ H m o of micellization were found as negative for all the cases. • Negative Δ G m o and Δ H m o values indicate that micelization procedure is a voluntary situation that occurs spontaneously. • Positive Δ S m o values were observed due to the increase in disorder in the solution with micelle formation. The micellization behaviour and thermodynamic properties of synthesized cationic gemini surfactant (12-2-O-12-12), N,N′-didodecyl-N,N,N′,N′-tetramethyl-N,N′-(oxybis(ethane-2,1-diyl))-diammonium dibromide were studied in the presence of organic solvents for four different temperatures (25, 30, 35 and 40 °C). Aqueous solutions of 10 % and 20 % methanol (MeOH), ethanol (EtOH), isopropanol (IPOH) and dimethyl sulfoxide (DMSO) were used as solvents. The critical micelle concentration (CMC) of cationic gemini surfactant and the degree of counterion dissociation (α) were determined by the conductometric method. Using the CMC and α values for each of the four temperatures, the values of the standard Gibbs free energy (Δ G m o), Gibbs free energy of transfer (Δ G m , t r a n s o) , enthalpy (Δ H m o), and entropy (Δ S m o) of micellization were calculated. It was observed that the CMC and α values increased with increasing solvent percentage and temperature. It was found that in all cases, the standard Gibbs free energy and enthalpy values were negative while both the micellization entropy and the standard Gibbs free energy of transfer are positive. Negative Gibbs free energy values indicated that micellization was a spontaneous situation, while positive entropy values indicated the existence of a disordered situation. The positive Δ G m , t r a n s o values show that the presence of solvents makes the environment unfavorable for micelle formation. [ABSTRACT FROM AUTHOR]

• Thermodynamic and physicochemical properties of structurally similar amphiphilic drugs is discussed. • Various techniques used to study the amphiphilic drug is reviewed. • Tricyclic antidepressants and phenothiazines classified based on temperature-self-aggregation relation. Amphiphilic drug-based research is a progressing multidisciplinary theme. This article describes the physicochemical properties and thermodynamic parameters of several structurally comparable tricyclic antidepressant drug (TAD) and phenothiazine-derived drug (PDD) self-aggregates. The self-organization of such drugs, at given conditions, can be monitored by spectroscopic, electrochemical, computational and thermal analyses. The values of critical micelle concentration (cmc), Gibbs energy, enthalpy, and entropy of micellization in the reported studies have been analyzed to comprehend the behaviour of these drugs with respect to temperature. The physicochemical properties such as maximum surface excess concentration, minimum area per molecule, surface pressure at cmc and adsorption capacity were also compared for various TADs and PDDs. More focused research on the self-aggregation of amphiphilic drugs may catalyze their applications, particularly in drug delivery and/or designing the new molecules. [ABSTRACT FROM AUTHOR]

Biomass syngas can be considered as a supplementary fuel to partially substitute coal, which is beneficial to CO2 emission reduction. For the case study, the influences of co-firing typical biomass syngas (gasification from palm, straw, and wood) with coal on the thermodynamic parameters of a 300 MW tangentially fired boiler are evaluated through a thermal calculation based on the principles of mass conservation, heat conservation, and heat transfer. The effects of boiler loads, biomass syngas species, and consumption rates are discussed. The results show that the introduction of biomass syngas weakens the radiative characteristics of the flame and reduces the furnace exit flue-gas temperature. As 3 × 104 m3 h−1 of wood syngas is introduced, the decrement of thermal efficiency reaches 0.4%, while that of the coal consumption rate is 5.1%. The retrofitting of the boiler was not necessary and the corrosion of the low-temperature heating surface did not appear. The CO2 annual emission reduction could achieve 0.001 to 0.095 million tons for palm syngas, 0.005 to 0.069 million tons for straw syngas, and 0.013 to 0.107 million tons for wood syngas with increasing biomass syngas consumption rates under the full load. Moreover, the main thermodynamic parameters changed more significantly under the low loads.

Artocarpus Heteropyllus Peel as non-toxic fruit waste contained some antioxidants. Peel extract of Artocarpus Heteropyllus could used as inhibitor to reduced corrosion rate. In this study, artocarpus heteropyllus peel extract was used as inhibitor corrosion to protect pure copper in 1 M HNO3. The inhibitor concentration was varied of 0–800 ppm. The measurement of corrosion rate was conducted by applying potentiodynamic polarization methods. The inhibitor performance, isotherm adsorption the thermodynamic parameter and kinetic activation energy were analyzed. Artocarpus heteropyllus peel extract was mixed inhibitor type and tended to anodic inhibitor type. The highest inhibitor efficiency was 98%. It occurred at its concentration of 800 ppm and temperature of 25 °C. Isothermic adsorption pattern followed the Frumkin adsorption isotherm equation. Inhibitor molecules were adsorbed on the pure copper surface physically.

• Solubility study of mesalazine in ternary mixture of ethanol, propylene glycol, and water at different temperatures. • Correlation/back-calculation of the solubility data by some mathematical models. • Calculation of thermodynamic parameters by using the van't Hoff and Gibbs equations. Mesalazine is a low-permeable and low-soluble drug, which makes it a class IV drug in the Biopharmaceutics Classification System. Hence, its solubilization can be helpful for various stages of formulation development. The purpose of this study was to investigate the solubilization manner and thermodynamics of mesalazine in ternary solvent combinations of {ethanol (1) + propylene glycol (2) + water (3)} using the shake-flask technique at (298.2–313.2) K. In the following, the mathematical representation of the acquired solubility data using some popular models was evaluated. The accuracies of the applied models were described by percentages of mean relative deviation (MRD%). Based on obtained results (MRD % < 10.0), it can be concluded that the trained models can adequately predict the solubility of mesalazine in the investigated ternary solvent combinations. The findings also revealed that the solution composition and temperatures greatly influence the solubility of mesalazine. In addition, the thermodynamic characteristics of the mesalazine dissolution process indicate that the mesalazine dissolution process is endothermic and entropy-driven. The generating data in the current work also expands the available solubility database for mesalazine in the solvent mixtures. [ABSTRACT FROM AUTHOR]

Pre-treatment of biomass has garnered significant research attention to facilitate biomass utilization. This study examines the effect of torrefaction on the pyrolysis characteristics of kenaf (Hibiscus cannabinus L.), which grows in South Korea and has a relatively short life cycle as well as a low production cost among herbaceous biomass. In this study, raw kenaf (RK) and torrefied kenaf (TK) were prepared in an inert atmosphere. Torrefaction was carried out in a bed reactor for 30 min at 503, 523 and 553 K, and pyrolysis was performed at six heating rates and analyzed using thermogravimetric analysis. The results showed that the optimal temperature for RK torrefaction based on the energy-mass co-benefit index was 523 K, owing to a higher energy density and low volume. The torrefaction and a higher heating rate resulted in the weight loss and decomposition rate (derivative thermogravimetric) curves moving to a higher temperature region, and improvement in the devolatilization index of the TK. The activation energy was calculated using three methods (Kissinger, Flynn–Wall–Ozawa, and Kissinger–Akahira–Sunose), with all indicating that the activation energy of the TK was greater than that of RK. Additionally, in terms of thermodynamic parameters, the TK had a higher frequency factor, higher enthalpy, slightly lower Gibbs free energy, and higher entropy than those of RK. These kinetic and thermal behavior results are useful for designing pyrolysis processes wherein TK is used as a feedstock; moreover, they provide a useful reference for TK heat conversion applications.

Anthocyanidin-3,5-O-diglucosides are the main pigments in red wines made from non-vinifera and hybrid species. In this work, intermolecular copigmentation between three common anthocyanidin-3,5-O-diglucosides and three types of phenolic copigments was systematically investigated in model wine solutions through experimental and theoretical methods. The impact of the sugar moiety at the C5 position of anthocyanin A ring was studied emphatically. Results showed that the anthocyanidin-3,5-O-diglucosides produced much stronger hyperchromic effects compared to the anthocyanidin-3-O-glucosides. Thermodynamic analysis and theoretical calculations suggested higher affinity of the anthocyanidin-3,5-O-diglucosides towards copigments (larger K values and lower ∆G) than corresponding monoglucosidic anthocyanins, mainly due to the enhancement of hydrogen bonds and van der Waals forces resulting from the additional glucose. In conclusion, the results revealed that the glucose at the C5 position of anthocyanin A ring could play a positive role in copigmentation, thus may lead to strong copigmentation effects in these wines.

The current approach involves the kinetic investigation of Thiobenzamide (TB) and cyclohexanone thiosemicarbazone (CTSC) in solution with 3-chloroacetylacetone(3-CAA). The study revealed a second-order rate constant with respect to both reactants, thioamide and an α-halo carbonyl compound. The energy of activation (Ea) was found to be Ea 48.8176kJ/mol/K for thiobenzamide and 33.08692157 kJ/mol/K for Cyclohexanone thiosemicarbazone. The salt effect study showed the formation of ionic species during the reaction. The reactions were studied with respect to changes in dielectric constant using solvent systems like water-ethanol and water-isopropanol. [ABSTRACT FROM AUTHOR]

The fundamental binding of single-stranded (ssDNA) and double-stranded DNA (dsDNA) with graphene oxide-Ag nanocomposites (GO-AgNCPs) has been systematically investigated by multi spectroscopic methods, i.e. ultraviolet-visible (UV–vis) absorption, fluorescence spectroscopy, and circular dichroism (CD). The experimental and theoretical results demonstrate that both ssDNA and dsDNA can be adsorbed onto the GO-AgNCPs surface. All of the evidence indicated that there were relatively strong binding of ssDNA/dsDNA with GO-AgNCPs. The article compares the differences in binding between the two types of DNA and the nanomaterials using spectroscopic and thermodynamic data. UV–vis absorption spectroscopy experiments indicate that the characteristic absorbance intensity of both ss DNA and ds DNA increases, but the rate of change in absorbance is different. The fluorescence results revealed that ss/dsDNA could interact with the GO-AgNCPs surface, in spite of the different binding affinities. The K a value of ssDNA binding with GO-AgNCPs is greater than that of dsDNA at each constant temperature, indicating that the affinity of dsDNA toward GO-AgNCPs is comparatively weak. Molecular docking studies have corroborated the mentioned experimental results. The calculated thermodynamic parameters showed that the binding process was thermodynamically spontaneous, van der Waals force and hydrogen bonding played predominant roles in the binding process. The mechanism of ss/ds DNA binding with GO-AgNCPs was also investigated, and the results indicated that GO-AgNCPs directly binds to the minor groove of ss/ds DNA by replacing minor groove binders. [ABSTRACT FROM AUTHOR]

In this critique, we address multiple shortcomings identified in a recent article published in this journal concerning the adsorption of Pd(II) and Pt(IV) ions from acidic solutions using a novel nanoadsorbent. The identified issues encompass erroneous model equations, unverified adsorption mechanisms, inappropriate application of simplified models, incorrect parameter units, and flawed thermodynamic parameters. [ABSTRACT FROM AUTHOR]

• The values of low and high frequency dielectric constants decrease with concentration. • Both the relaxation times show almost linear behavior with sucrose concentration. • The antiparallel solute dipole alignment increases with solute concentration. • The number of water molecules bounded to solute decreases with solute concentration. • Thermodynamic properties suggest strong hydrogen bonding between sucrose and water. Dielectric relaxation of aqueous sucrose [C 12 H 22 O 11 ] has been carried out over the temperature range of 278.15 K to 298.15 K in the frequency region of 0.01 GHz to 30 GHz using time domain reflectometry technique (TDR). Two modes of relaxation processes were observed, namely low-frequency (primary) and high-frequency (secondary) relaxation. The rotating motion of sucrose molecules is primarily responsible for the low-frequency dispersion of relaxation, whereas the reorientation of bulk water is responsible for the high-frequency dispersion of relaxation. Dielectric parameters, i.e., static dielectric constant (ε j), relaxation time (τ j), dipole moment (û), Kirkwood factor of low frequency relaxation (g 1), and thermodynamic parameters, i.e., free energy of activation (ΔF j), enthalpy of activation (ΔH j) and entropy of activation (ΔS j) were calculated. The static dielectric constant (ε j), which was detected for both relaxation processes, i.e., ε 1 and ε 2 , was shown to be decreasing with increasing temperature and solute molecule concentration. Over the course of all the concentrations used, it was observed that the τ 1 and τ 2 both increased with the sucrose concentration and also towards the low temperature. The decreasing trend of correlation factor (g 1) suggests a strong possibility of antiparallel alignment of dipoles between sucrose molecules towards higher concentrations. Solute-solute antiparallel correlation seems to be reduced at lower temperature. Higher values of dipole moments at lower sucrose concentrations imply reduced antiparallel alignment between sucrose molecules, while lower values of effective dipole moments (μ eff) obtained using Cavell and Kirkwood-Frohlich (KF) equations increase the likelihood of antiparallel alignment of sucrose dipoles. In terms of hydration dynamics, the total water molecules that are effectively locked by the sucrose molecules (Z ib) were also calculated. Finally, dielectric parameters have been corroborated by thermodynamic parameters. Figure: Static permittivity (ε') and dielectric loss (ε") of aqueous sucrose as the function of frequency at different concentration and temperatures. The spectra show that as the concentration of sucrose increases, the dielectric permittivity decreases gradually and the loss peak shifts to the low frequency side. This suggests that at higher concentrations, water and sucrose molecules associate molecularly [Display omitted]. [ABSTRACT FROM AUTHOR]

The branched cationic tetrameric surfactant (4C14tetraQ) that the length of four hydrocarbon chains is 14 was synthesized, and the molecular structure has been confirmed via FT-IR, 1H NMR and elemental analysis. The inhibition behavior for N80 carbon steel in hydrochloric acid solution was studied with weight loss measurements at 25–65°C while electrochemical impedance and polarization were carried out at 25°C. The results of weight loss measurements show that the synthesized surfactant has good inhibitive performance, and its inhibition efficiency was increased with the increment of both temperature and concentration. Polarization curves indicate that the cationic tetrameric surfactant may serve as a mixed-type inhibitor. In addition, it is found that the adsorption behavior of 4C14tetraQ follows Langmuir adsorption isotherm, and the adsorption process is an endothermic process couple with the increase in entropy. [ABSTRACT FROM AUTHOR]

In the present study, natural bentonite and acid-thermal co-modified bentonite were utilized for Acid Blue 25 (AB25) removal. The adsorption experiments were executed at the temperature values of 298K, 308K and 318K. According to the results, Freundlich isotherm becomes more convenient model compared with Langmuir and Temkin model. Freundlich model coefficients rise when the temperature increases. Kinetic coefficients were calculated by pseudo first order (PFO) and pseudo second order (PSO) models. Coefficients of R2 evaluated were higher than 0.99 with experimental and obtained qe values close to each other explained that this process fits PSO kinetic model. The concentration of AB25 elevates from 30 to 80 mg/L adsorption capacity onto natural, acid-thermal co-modified bentonite increases from 8.36 to 27.00 mg/g and 9.30 to 29.09 mg/g for 298 K, respectively. Absolute values of free energy of AB25 onto natural and acid-thermal co-modified bentonite changes from 4.065 kJ/mol to 8.586 kJ/mol, respectively. Enthalpy values of AB25 onto natural and acid-thermal co-modified bentonite changes from 5.483 kJ/mol to 11.249 kJ/mol and entropy values of AB25 on natural and acid-thermal co-modified bentonite changes from 4.759 J/mol K to 8.940 J/mol K, respectively. It was also found that modified bentonite has higher adsorption capacity than natural bentonite.

The addition of corrosion inhibitors into the acidic environment is an environmental modification to control the rate of corrosion. Organic compound inhibitors become an environmentally friendly alternative. In this study, research and analysis have been carried out on jackfruit peel extract as a corrosion inhibitor for AISI 1037 carbon steel protection in 1M HCl solution. Variation of inhibitor concentration is 200-3000 ppm. Corrosion rate measurements were performed by applying weight loss and potential polarization methods. The addition of inhibitor concentrations up to 1000 ppm increased the inhibitor efficiency up to 90.98%, but the efficiency decreased at concentrations of 2000 ppm and 3000 ppm. The adsorption inhibitors that occurred in this study was physical adsorption. It followed the Langmuir isothermal adsorption. The fungsional group of the film layer on the carbon steel surface indicated that the jack fruit peel extract compounds was adsorbed on the steel surface. [ABSTRACT FROM AUTHOR]

In this study, we investigated the interaction of epigallocatechin gallate (EGCG) with bovine serum albumin (BSA) by fluorescence method and protein‐ligand docking. We separated EGCG from green tea using the chromatographic method and analyzed structural activity relationships of the EGCG. The results show that EGCG is a strong quencher of BSA fluorescence and binds with BSA with high affinity. The binding parameters (binding constant, the number of binding sites) were determined by the Ward equation. From the thermodynamic parameters, calculated according to the van’t Hoff equation, the enthalpy change ΔH°, and entropy change ΔS° were found to be -22.67 kJ/mol and 14.92 J/mol/K, respectively. These values suggest that apart from an initial hydrophobic association, the complex is held together by electrostatic and hydrogen bonding. In the docking simulation, the lowest free energies for the interaction of EGCG with tryptophan residues was −21.92kJ/mol (Trp134) and −24.7 kJ/mol (Trp213). The binding between EGCG and BSA consists of hydrogen bonds (Trp213) and hydrophobic interactions (Trp134).

Surface tension of a series of poly(ethylene glycol)-octyl sulfosuccinates at different temperatures was measured, and the interfacial properties were investigated in the absence and presence of inorganic salts. Surface tension results indicate that critical micelle concentration (CMC) values of five surfactants (C8-PEG200, C8-PEG400, C8-PEG600, C8-PEG800, and C8-PEG1000) decrease as the molecular weight of polyethylene glycol (PEG) segments and the experimental temperature increases. The surface activity of the C8-PEG series changes with temperature, and the surface tension at the CMC (γCmC) of the C8-PEG series decreases initially and then increases as the PEG molecular weight increases. This behavior may be attributed to the dehydration of the surfactant molecules, resulting in the change of hydrophile-lipophile balance for the different EO numbers in the surfactant molecules, which form a different surface energy film at the air-water interface. Negative ΔGm indicates that the micellization process of these surfactants is spontaneous and an entropically driven process. For the water/alkane interface, these surfactants have low interfacial activity. The interfacial tension (IFT) between these surfactants and alkanes increases first and then decreases with the increase in the molecular weight of PEG segments. After the addition of salt, the interfacial activity of the investigated surfactants increases significantly. The IFT between C8-PEG800 and 10-12 alkanes and between C8-PEG1000 and 12-16 alkanes reaches a low IFT magnitude of 10-2 mN m-1 in the presence of 0.5% CaCl2 or the mixed inorganic salts 0.5% NaCl+0.5% CaCl2. [ABSTRACT FROM AUTHOR]

hydrogels were synthesized by free radical polymerization of Acrylic acid (AAc) and 3-sulfopropyl acrylate potassium salt (KSPA) in aqueous solution using N,N'-methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as initiator. This were designated as copolymer KSPAC. Water swelling studies of copolymer hydrogels with different mol and initiater percent were performed. The hydrogel showing the highest swelling percent in water has been modified using Acrloyl GuarGum (AGG). hydrogel with three different weight percent of AGG were synthesized, designated as AGGKSPAC1,2,3 respectively. AGGKSPAC2 was found to show much higher ES% than the AGGKSPAC1 & AGGKSPAC3. These hydrogels have been employed as carriers and in vitro releasing materials for Gentamicin drug. Drug loaded and unloaded hydrogels were characterized from FTIR, 13C NMR, DTA, TGA SEM, XRD BET. At different pH the absorption and release of drugs were studied. [ABSTRACT FROM AUTHOR]

In the present work we have investigated the stability constant of seven Schiff bases with trivalent rare earth metal ion Lanthanum using a pH metric titration technique in 80% (v/v) ethanol-water mixture at three different temperatures 298K, 308K & 318K at an ionic strength of 0.1M NaClO4. The Calvin-Bjerrum method as adopted by Irving-Rossotti has been employed to determine metal-ligand stability constant logK values. The thermodynamic parameters such as, Gibb's free energy change (ΔG), entropy change (ΔS) and enthalpy change (ΔH) associated with the complexation reactions were calculated. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, sulfonated WPS (SWPS) was synthesized using concentrated sulfuric acid (Con. H 2 SO 4) at various concentrations (0.01–0.05 mol.dm −3) and temperatures (313 K, 333 K, and 353 K) and the structure was confirmed by various analytical techniques. The degree of sulfonation (DS) values was determined using cation exchange capacity (CEC), 1H NMR, and UV–visible spectroscopy, and to investigate the influence of temperature and various concentration of H 2 SO 4 during the sulfonation reaction. The conductivity of the SWPS was calculated and found to range from 0.23 × 10−6 S.cm −1 to 40.2 × 10−6 S.cm −1. The theoretical solubility parameters of SWPS were determined and compared with experimental values. Using Frenkel-Erying equation, Thermodynamic parameters of SWPS was calculated and also evaluated the correlation between the intrinsic viscosity (η) and viscous flow activation free energy (ΔG v). Our findings contribute to a better understanding of the sulfonation reaction of WPS and the potential applications of SWPS as a functional material. [ABSTRACT FROM AUTHOR]

[Display omitted] • Xylanase from A. pullulans was partially purified in 6.8-fold and yield of 69.4 %. • Xylanase extracts showed great activity at pH 4.5 and 50 °C and stability at 40 °C. • Crude and purified xylanase produced xylooligosaccharides (XOS, 7.7 and 7.9 mg/mL). • XOS accounted 86.1 % and 90.2 % in xylan hydrolysates after 24 h of reaction. • Xylan hydrolysates were mostly composed of xylobiose and xylotriose. In this study, crude and partially purified xylanase from Aureobasidium pullulans CCT 1261 were characterized and applied in beechwood xylan hydrolysis to obtain xylooligosaccharides (XOS). Fractional precipitation (0–30 %/30–60 %) with ammonium sulfate allowed partial purification of xylanases in 6.8-fold and recovery of 69.4 %. Both extracts exhibited optimum activity at 50 °C and pH 4.5, and greater stability at 40 °C within the studied range. The thermostability parameters (k d , t 1/2 , ΔH*, ΔG*, ΔS*) of the extracts indicated the enzyme denaturation by the increment in temperature from 40 °C to 60 °C; its process was endothermic and led to protein unfolding in a more random structure. Crude xylanase showed a lower value of the Michaelis-Menten constant (25 mg/mL) than the partially purified enzyme (50 mg/mL). In hydrolysis reactions, total XOS contents (7.7 mg/mL and 7.9 mg/mL) and XOS yields (25.7 % and 26.5 %) were equal statistically using the crude or partially purified extracts, differing only in the amount of xylose released. The hydrolysates were mainly composed of potential prebiotics, i.e., xylobiose (50.9 % and 53.8 %) and xylotriose (30.9 % and 32.8 %). Based on these results, the use of crude and partially purified xylanase from A. pullulans showed a promising perspective for xylan hydrolysis to produce XOS. [ABSTRACT FROM AUTHOR]

The physicochemical properties of cetyltrimethylammonium bromide (CTAB) in pure water and ethanol-water mixtures in the presence and absence of MnSO4.6H2O were studied by measuring the conductivity at room temperature. The concentration range of CTAB was ~1.00 × 10-5 M to ~1.00 × 10-2M and the concentration of MnSO4.6H2O was 0.001 M, 0.005 M, 0.01 M. With increasing ethanol content in the solvent composition, the critical micelle concentration (CMC) and the degree of micellar dissociation (a) of CTAB increased. With the help of CMC and α, the standard free energy of micellization (ΔGm0) was evaluated. With an increase in ethanol content, the negative values of ΔGm0 decreased. CTAB micellization was tested in the context of specific solvent parameters. The solvent conductivity ratio at CMC to limiting conductivity was employed as a solvophobic influence. The addition of salt (MnSO4.6H2O) decreases the CMC of CTAB due to the screening of the electrostatic repulsion of the head groups. Here, we report that micellization is strongly influenced by salt concentration. [ABSTRACT FROM AUTHOR]

Thermodynamics on a Cantor-lattice Ising model is studied to clarify effects of fractal structure. Exact solutions based on the transfer matrix are investigated for finite size systems, and it is found that there is non-trivial relationship between entropy and fractal structure. In order to understand the nature in the thermodynamic limit, the renormalization method is applied. The results suggest a possibility of residual entropy due to the competition between non-uniformity of the fractal structure and uniform external field. These pave a simple way to approach general behaviors of non-uniform systems including fractal structures, such as quasicrystals. [ABSTRACT FROM AUTHOR]

In the present work, extended X‐ray absorption fine‐structure (EXAFS) investigations of Co69FexSi21–xB10 (x = 3, 5, 7) glassy ribbons were performed at the Co K‐edge. The magnitude of the first peak of the Fourier transforms of the EXAFS signals is found to increase monotonically with increasing Si concentrations indicating the formation of the localized ordered structure at the atomic scale. The Co–Si coordination number (CN) increases at the expense of the CN of Co/Fe. Smaller interatomic distances are observed in the glassy phase compared with that in the crystalline phase which promotes the stability of the glassy phase. Calculations of the thermodynamic parameter (PHSS), cohesive energy (EC) and the atomic radius difference (δ) parameter show that the alloy composition Co69Fe3Si18B10 has a good glass‐forming ability (GFA) with the highest CN of Si compared with other compositions. A linear correlation of CN with that of the GFA parameter (PHSS) exists and the CN also plays a crucial role in the GFA of the glassy alloys. This parameter should be considered in developing different GFA criteria. [ABSTRACT FROM AUTHOR]

Nitrocellulose (NC), a highly energetic compound, is widely used in nitrolacquer, celluloid, binder, propellants, and explosives. Many studies have focused on the inflammability and instability of NC, but few have investigated its use as a propellant binder. To optimize the properties of NC as a propellant binder, this study introduced 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][NTf2]) as an additive. This study focuses on the thermal pyrolysis behavior and decomposition mechanism of pure NC (NC-P), NC-NTf2 (i.e., NC mixed with [Bmim][NTf2]), and NC-NTf2-eth (i.e., NC mixed with 30% [Bmim][NTf2] and 70% ethanol). First, the thermal degradation processes of NC and [Bmim][NTf2] were investigated using thermogravimetric analysis. In addition, the essential thermodynamic parameters of NC-P, NC-NTf2, and NC-NTf2-eth were obtained by differential scanning calorimetry, and the apparent activation energies were evaluated using the Starink method and Friedman method. The results show that NC-NTf2 has low onset decomposition temperature, low activation energy, and high energy release rate. Moreover, NC-P, NC-NTf2, and NC-NTf2-eth were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy to verify and interpret the thermal analysis results obtained. [ABSTRACT FROM AUTHOR]

Stability constant of Benazepril hydrochloride drug with transition metal ions Fe3+, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+ using a pH metric titration technique in 20%(v/v) ethanol-water mixture at three different temperatures 300K, 310K & 320K at an ionic strength of 0.1M NaClO4 were studied. The Calvin-Bjerrum method as adopted by Irving-Rossotti has been employed to determine metal-ligand stability, constant logK values. The trend in the formation constants for transition metal ions follows the order: Fe3+ > Cu2+ > Cd2+> Co2+ > Zn2+ > Ni2+. The thermodynamic parameters, such as Gibb’s free energy change (ΔG), entropy change (ΔS), and enthalpy change (ΔH) associated with the complexation reactions, were calculated.

In the present study, natural bentonite and acid-thermal co-modified bentonite were utilized for Acid Blue 25 (AB25) removal. The adsorption experiments were executed at the temperature values of 298K, 308K and 318K. According to the results, Freundlich isotherm becomes more convenient model compared with Langmuir and Temkin model. Freundlich model coefficients rise when the temperature increases. Kinetic coefficients were calculated by pseudo first order (PFO) and pseudo second order (PSO) models. Coefficients of R2 evaluated were higher than 0.99 with experimental and obtained qe values close to each other explained that this process fits PSO kinetic model. The concentration of AB25 elevates from 30 to 80 mg/L adsorption capacity onto natural, acid-thermal co-modified bentonite increases from 8.36 to 27.00 mg/g and 9.30 to 29.09 mg/g for 298 K, respectively. Absolute values of free energy of AB25 onto natural and acid-thermal co-modified bentonite changes from 4.065 kJ/mol to 8.586 kJ/mol, respectively. Enthalpy values of AB25 onto natural and acid-thermal comodified bentonite changes from 5.483 kJ/mol to 11.249 kJ/mol and entropy values of AB25 on natural and acid-thermal co-modified bentonite changes from 4.759 J/mol K to 8.940 J/mol K, respectively. It was also found that modified bentonite has higher adsorption capacity than natural bentonite. [ABSTRACT FROM AUTHOR]

We have examined the effect of bifunctional group in the same cross-linkage degree on the Li isotope fractionation in the cation exchange reaction in the aqueous solutions ranging in temperature from 278 to 333 K. For this purpose, the sulfonated pyridine-styrene-divinylbenzene resin with the cross-linkage degree of 50 wt%, embedded in porous silica beads was successfully synthesized by a typical polymerization method. The isotope separation coefficients (ε) per unit mass (ε/ΔMass) was 8.1 × 10–4 at 298 K. Therefore, the effect of bifunctional group against the ε/ΔMass value has been discussed, compared with those of previous works. [ABSTRACT FROM AUTHOR]

SnSe and Sm 1 − x Ce x SnSe 2 compounds based on SnSe have been synthesized. Thermal properties of SnSe and Sm 1 − x Ce x SnSe 2 compounds within x = 0. 0 2 – 0. 5 concentration ranges of Ce atoms have been investigated using Differential Thermal Analysis (DTA). Thermodynamic parameters were calculated based on DTA spectra within 3 0 0 K ≤ T ≤ 1 2 5 0 K temperature intervals. It was determined from the relation of different rates concentrations of Sm and Ce elements on energies that Sm 1 − x Ce x SnSe 2 system compounds have their high symmetric structure in the form of Sm 0. 2 5 Ce 0. 7 5 SnSe 2 . Thermodynamic parameters were determined for each system and the changing mechanism of these parameters depending on concentration of Ce atoms was performed. [ABSTRACT FROM AUTHOR]

The influences of hydrochloric acid washing on the pyrolysis behavior and thermodynamic parameters of sweet sorghum stalk were investigated using thermogravimetric analysis and Fourier transform infrared (FTIR) in this study. Hydrochloric acid washing influenced the quality of sweet sorghum stalk and changed the pyrolysis curves shape. By acid pretreatment, the 98% of metals and 47.15% of extractives were removed, the maximum weight loss rates were improved by 1.53–1.64 times, the volatiles yields were enhanced about 10%, and the high heat value increased from 15.59 to 18.27 MJ/kg. Lower activation energies were obtained for acid-washed samples at conversion rate >0.45 by the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose (KAS) methods. The higher Gibbs free energy of 133.94–137.79 kJ/mol could provide more energy for pretreatment samples, and FTIR analysis confirmed acid washing could change functional groups in samples. • Hydrochloric acid washing greatly removed the metals of sweet sorghum stalk. • The DTG curves of sweet sorghum stalk appeared four obvious mass-loss peaks. • Pretreatment significantly affected the shapes of pyrolysis curves. • Hydrochloric acid washing increased volatiles yield and HHV and Gibbs free energy. • Pretreatment reduced activation energy as conversion degree was more than 0.45. [ABSTRACT FROM AUTHOR]

A new Cd(II) complex, [Cd(H4pbidc)(H2O)] n (1), incorporating 2,2′-(propane-1,3-diyl)bis(1H- imidazole-4,5-dicarboxylic acid) (H6pbidc) was synthesized and characterized by elemental analysis, infrared spectra and X-ray single-crystal diffraction. In complex 1, each Cd(II) ion is hepta-coordinated, showing a significantly distorted pentagonal-bipyramidal coordination environment. Adjacent Cd(II) ions are alternately joined through two carboxylate oxygen atoms and two bridging water molecules resulting in a one-dimensional chain structure. In the solid state, adjacent chains are further linked by hydrogen bonds, forming a three-dimensional supramolecular architecture. Meanwhile, the interactions of complex 1 with bovine serum albumin were analysed by fluorescence measurements under physiological conditions. The results indicated that the fluorescence intensity of bovine serum albumin was decreased considerably upon the addition of complex 1 through a static quenching mechanism with formation of one binding site. The negative values of the thermodynamic parameters including enthalpy change (Δ H), entropy change (Δ S) and Gibbs free energy change (Δ G) showed that hydrogen bonding and van der Waals forces were the main interactions in the binding of complex 1 to bovine serum albumin, and the binding process is spontaneous in thermodynamics. [ABSTRACT FROM AUTHOR]

The influence of water-soluble polyethylene glycols PEG200 on the properties of sodium bis(2-ethylhexyl)-sulfosuccinate (AOT) water-in-isooctane microemulsions has been investigated by conductivity measurement and isothermal titration microcalorimetry (ITC). The percolation temperatures (T p), the thermodynamic properties of droplet aggregation and the interaction enthalpy (−Δ H φ) between droplets for AOT/water/PEG200/isooctane with different PEG concentrations and a fixed molar ratio of water to surfactant ω = 22.2 were determined. Based on a two-stage thermodynamic approach of the percolation, we obtained the fusion enthalpy (Δ H f 0) of the close contact droplets by a combination of the droplet aggregation enthalpy (Δ H ag 0) and −Δ H φ. It was found that both (−Δ H φ) and (Δ H f 0) varied with the concentration of PEG200 (c PEG) and had the extreme value at c PEG = 25 g L−1. This phenomenon was interpreted by the variation of interface rigidity due to the varied distributions of added PEG200 between the water pool and the surfactant interface. [ABSTRACT FROM AUTHOR]

Reducing organic groups on hydrophobic silica aerogels (SA) is worth exploring for lowering their thermal hazard risk. In this work, we used dimethyldichlorosilane (DMDCS) to modify silica alcogels, investigated the effects of DMDCS concentration and focused on the thermal hazard assessment of the DMDCS modified SA (DSA). It was turned out that the DSA had less −CH3 content in spite of the thermal stability close to the trimethylchlorosilane modified SA (TSA), about 240 °C. The kinetics study suggested the apparent activation energy (Ea) could be divided into two segments, corresponding to the two processes in the pyrolysis. The positive enthalpy and entropy changes indicated that the thermal oxidation of the DSA was an exothermic reaction, which could not occur without external energy supply. The average Ea of the DSA was far larger than that of the TSA and the gross calorific value of the DSA decreased by about 12% compared with that of the TSA. All these results drew a conclusion that the DMDCS modified SA reduced the thermal hazard to some degree, which provided one possible solution to further lower the thermal hazard of hydrophobic SA. Highlights: Dimethyldichlorosilane modified silica aerogels (DSA) were prepared at the optimum concentration of 4%. Kinetic and thermodynamic behavior of DSA were studied in detail. DSA has larger apparent activation energy than trimethylchlorosilane modified silica aerogels (TSA). DSA has lower thermal hazard than TSA for a less gross calorific value. [ABSTRACT FROM AUTHOR]