New group contribution method for the prediction of normal melting points

Ponce, Alejandro A. Pérez; Salfate, Ignacio; Pulgar-Villarroel, Geraldo; Palma-Chilla, L.; Lazzús, Juan A.

doi:10.1134/s1810232813030065

Cited by 9 publications

(4 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, Gong et al reported that at 773 K, there are no sugars or anhydrosugars detected during the reaction, because almost all of the cellulose have already decomposed at such high temperature. For the normal melting point, estimation using both Joback and Perez-Ponce methods gave quite a similar value. Oja and Suuberg recorded a melting point of 453 K for levoglucosan and 513 K for cellobiose.…”

Section: Resultsmentioning

confidence: 69%

“…The parameters evaluated in this study are the critical properties, ideal gas properties, and condensed gas properties. The critical properties such as critical temperature (T c ), critical volume (V c ), and critical pressure (P c ) were estimated employing the methods of Joback 30 and Lydersen et al; 55 the enthalpy of vaporization via the methods of Joback, 30 Riedel, 57 and QPPR methods; the enthalpy of fusion by the Joback 30 method; the normal boiling point by Joback 30 and Stein and Brown 31 methods; and the normal melting point by Joback and Reid 60 and Peŕez Ponce et al 58 methods. The thermodynamic properties estimated using DFT were heat 1 shows the most thermodynamically stable molecular structures identified as the likely constituents of the dehydrated anhydrooligo-sugars.…”

Section: Validation Of Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

Elucidation of Structure and Physical Properties of Pyrolytic Sugar Oligomers Derived from Cellulose Depolymerization/Dehydration Reactions: A Density Functional Theory Study

et al. 2023

View full text Add to dashboard Cite

Fast pyrolysis of lignocellulosic materials is a promising research area to produce renewable fuels and chemicals. Dehydration is known to be among the most important reaction families during cellulose pyrolysis; water is the most important product. Together with water, dehydration reactions also form a range of poorly known oligomer species of varying molecular sizes, often collected as part of the bio-oil water-soluble (WS) fraction. In this work, we used electronic structure calculations to evaluate the relative thermodynamic stabilities of several oligomer species from cellulose depolymerization intermediates undergoing three consecutive dehydration events. A library of the thermodynamically favored candidate molecular structures was compiled. Results revealed that most of the water molecules are eliminated from the non-reducing end, forming thermodynamically more stable conjugated compounds. This is consistent with results reported in literature where dehydration reactions occur preferably at the non-reducing ends of oligomers. The theoretical Fourier-Transform Infrared Spectroscopy and NMR spectra of these proposed sugar oligomers conform qualitatively to the experimental result of pyrolytic sugars. Understanding their chemical structure could help to develop rational strategies to mitigate coke formation as sugars are often blamed to cause coke formation during bio-oil refining. The estimated physical–chemical properties (boiling point, melting point, Gibbs free energy of formation, enthalpy of formation, and solubility parameters among others) are also fundamental to conducting first-principles engineering calculations to design and analyze new pyrolysis reactors and bio-oil up-grading units.

show abstract

Section: Resultsmentioning

confidence: 69%

Section: Validation Of Simulationsmentioning

confidence: 99%

Elucidation of Structure and Physical Properties of Pyrolytic Sugar Oligomers Derived from Cellulose Depolymerization/Dehydration Reactions: A Density Functional Theory Study

et al. 2023

View full text Add to dashboard Cite

show abstract

“…This result is similar to what Fonts et al 19 obtained for larger compounds. For normal melting point, both methods (Joback and Reid 31 and Peŕez-Ponce et al 36 ) applied seem to agree with each other giving quite closer values. The estimated values for the dimer fragments in this work are close to the melting point of cellobiose (513 K) reported in the literature.…”

Section: Resultsmentioning

confidence: 73%

Theoretical Insights on the Fragmentation of Cellulosic Oligomers to Form Hydroxyacetone and Hydroxyacetaldehyde

Denson,

Terell,

Kostetskyy

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

The presence of heavy unknown oligomeric sugar products in bio-oil is evidenced in experimental results reported in the literature. In this paper, we study the fragmentation reactions yielding hydroxyacetone and hydroxyacetaldehyde from oligomeric sugars following previous work on dehydration reactions to propose structures of these oligomers. Hydroxyacetone and hydroxyacetaldehyde are primary products of cellulose fast pyrolysis, but the fragmentation reaction mechanism of these compounds from oligomers merits further study. The density functional theory approach was employed to study this reaction. Results revealed that hydroxyacetone and hydroxyacetaldehyde fragments are more favorably removed from the nonreducing end based on their thermodynamic stabilities. As a result of this study, we proposed new potential structures of unknown oligomeric sugars. Theoretical FTIR and NMR spectra were calculated so that in the future when these molecules are separated their experimental spectra and the theoretical ones herein reported can be used to confirm the structures of these oligomeric sugars. Also, the thermodynamics and physical properties of these compounds were estimated by using the group contribution method. These properties are essential in the design of technologies for bio-oil refining.

show abstract

“…A considerable disadvantage of Hezave's neural network model is the use of melting point temperature of ILs. Note that, for organic compounds, P erez Ponce et al [31] showed an AARD higher than 7.5% for several methods reported during years 1987e2006; additionally, they presented an AARD for three commercial softwares for predicting T m with an AARD higher than 12% and maximum deviations higher than 45%. For ILs, Huo et al [32] presented a group contribution method (GCM) for estimating the melting point of imidazolium-ILs with an AARD of 5.9% and maximum deviations higher than 32%.…”

Section: Resultsmentioning

confidence: 89%

Estimation of the thermal conductivity λ(T,P) of ionic liquids using a neural network optimized with genetic algorithms

Lazzús

2015

Comptes Rendus. Chimie

View full text Add to dashboard Cite

In this study, an artificial neural network was optimized using a genetic algorithm in order to estimate the thermal conductivity of ionic liquids at different temperatures and pressures. Experimental thermal conductivity data of 41 ionic liquids (400 experimental data points) in the range from 0.10 to 0.22 W m À1 K À1 were used to obtain the proposed method for the temperature range of 273e390 K and the pressure range of 100 e20,000 kPa. In addition, the molecular mass M and structure of molecules, represented by the number of well-defined groups forming the molecule, were provided as input parameters in order to characterize the different molecules of ionic liquids. A heterogeneous set of ionic liquids includes cations such as imidazolium, ammonium, phosphonium, pyrrolidinium, and pyridinium. It also includes anions such as halides, sulfonates, tosylates, imides, borates, phosphates, acetates, and amino acids. The whole dataset was divided into a training set with 300 experimental data points and a prediction set with 100 experimental data points. Several architectures were studied, and the optimum weights for the network were determined. The results showed that the proposed method to estimate the thermal conductivity of ionic liquids at different temperatures and pressures presented a good accuracy with lower deviations such as AARD less than 0.91% and R 2 of 0.9969 for the training set, and AARD less than 0.84% with R 2 of 0.9963 for the prediction set.

show abstract

New group contribution method for the prediction of normal melting points

Cited by 9 publications

References 17 publications

Elucidation of Structure and Physical Properties of Pyrolytic Sugar Oligomers Derived from Cellulose Depolymerization/Dehydration Reactions: A Density Functional Theory Study

Elucidation of Structure and Physical Properties of Pyrolytic Sugar Oligomers Derived from Cellulose Depolymerization/Dehydration Reactions: A Density Functional Theory Study

Theoretical Insights on the Fragmentation of Cellulosic Oligomers to Form Hydroxyacetone and Hydroxyacetaldehyde

Estimation of the thermal conductivity λ(T,P) of ionic liquids using a neural network optimized with genetic algorithms

Contact Info

Product

Resources

About