Carbohydrates in alkaline systems. I. Kinetics of the transformation and degradation of <scp>D</scp>-glucose, <scp>D</scp>-fructose, and <scp>D</scp>-mannose in 1 <i>M</i> sodium hydroxide at 22 °C

MacLaurin, Donald J.; Green, John W.

doi:10.1139/v69-658

Cited by 29 publications

(11 citation statements)

References 12 publications

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“…The second term is needed because we also want to optimize the variance parameters. This objective function was implemented in Python and its analytic derivatives with respect to the unknowns were computed with AutoGrad 79 . The minimization is carried out with the L-BFGS-B minimizer in SciPy, constraining all variance parameters to be positive 80 .…”

Section: Methodsmentioning

confidence: 99%

Hydration Free Energies in the FreeSolv Database Calculated with Polarized Iterative Hirshfeld Charges

Riquelme

Lara

Mobley

et al. 2018

J. Chem. Inf. Model.

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Computer simulations of bio-molecular systems often use force fields, which are combinations of simple empirical atom-based functions to describe the molecular interactions. Even though polarizable force fields give a more detailed description of intermolecular interactions, nonpolarizable force fields, developed several decades ago, are often still preferred because of their reduced computation cost. Electrostatic interactions play a major role in bio-molecular systems and are therein described by atomic point charges. In this work, we address the performance of different atomic charges to reproduce experimental hydration free energies in the FreeSolv database in combination with the GAFF force field. Atomic charges were calculated by two atoms-in-molecules approaches, Hirshfeld-I and Minimal Basis Iterative Stockholder (MBIS). To account for polarization effects, the charges were derived from the solute’s electron density computed with an implicit solvent model and the energy required to polarize the solute was added to the free energy cycle. The calculated hydration free energies were analyzed with an error model, revealing systematic errors associated with specific functional groups or chemical elements. The best agreement with the experimental data is observed for the AM1-BCC and the MBIS atomic charge methods. The latter includes the solvent polarization and present a root mean square error of 2.0 kcal mol−1 for the 613 organic molecules studied. The largest deviation was observed for phosphorus-containing molecules and the molecules with amide, ester and amine functional groups.

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Section: Methodsmentioning

confidence: 99%

Hydration Free Energies in the FreeSolv Database Calculated with Polarized Iterative Hirshfeld Charges

Riquelme

Lara

Mobley

et al. 2018

J. Chem. Inf. Model.

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“…time. These preliminary values and the reaction rate constants previously obtained (1) for the monosaccharide portion of the system were then refined on a computer as before (1). The final values of the rate constants Can.…”

Section: Derivation Of Reaction Rate Constantsmentioning

confidence: 99%

“…All apparatus and procedures used were as previously described (1). The nitrogen was Matheson Prepurified Grade, of 99.997% purity.…”

Section: Apparatrrs Atld Procedrrresmentioning

confidence: 99%

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Carbohydrates in alkaline systems. II. Kinetics of the transformation and degradation reactions of cellobiose, cellobiulose, and 4-O-β-D-glucopyranosyl-D-mannose in 1 M sodium hydroxide at 22 °C

MacLaurin¹,

Green²

1969

Can. J. Chem.

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Rates of isomerization, epimerization, and degradation reactions were measured for cellobiose (7), cellobiulose (8), and 4-0-S-D-glucopyranosyl-D-mannose (9) at 0.001 M in 1 M NaOH under N 2 in the dark at 22 "C. Reaction system resolution was by column chromatography on anion resins in the borate form. Assay for D-glucose (I), D-fructose (2), D-mannose (3), and 7,8, and 9 was by continuous automated colorimetry of column effluent with orcinol-sulfuric acid as reagent. Reaction rate constants (h-') found: k7, 0.078, k79 0.0005, k7,Io 0.002, ka7 0.022, kss 0.003, kal0.065, k8.12 0.023, k97 0.002, kss 0.013, 0.006 where 10, 11, and 12 are other products than 1, 2, 3, 7 , 8, and 9. Details for preparation of 8 and 9 are given.Canadian Journal of Chemistry, 47, 3957 (1969) Introduction Previous work (1) on D-glucose, D-fructose, and D-mannose gave rate constants for the various interconversions and degradations in 1 M sodium hydroxide at 22 "C. These data were necessary and were utilized in studying the present work with cellobiose, cellobiulose, and 4-0-P-D-glucopyranosyl-D-mannose. This permits further investigation of the "peeling" and "stopping" reactions, studied by Kenner and associates ( 2 4 ) and reviewed by Whistler and BeMiller (5).

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“…Through the enediols, the different acids may originate from fructose, glucose, mannose, or sorbose (Figure 2). From a kinetic viewpoint, the isomerization reactions were studied in more detail (De Bruijn, 1986;MacLaurin and Green, 1969;El Khadem et al, 1987, 1989Dubois, 1992); however, the results are not easy to compare and reuse due to the fact that the studies were preformed under different conditions. Among the most recent studies, it is important to note the works of De Bruijn (1986) and Dubois (1992).…”

Section: The Alkaline Degradation Of Fructose-backgroundmentioning

confidence: 99%

Modeling and Optimization of Lactic Acid Synthesis by the Alkaline Degradation of Fructose in a Batch Reactor

Cabassud

Cognet

Garcia

et al. 2005

Chemical Engineering Communications

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The present work deals with the determination of the optimal operating conditions of lactic acid synthesis by the alkaline degradation of fructose. It is a complex transformation for which detailed knowledge is not available. It is carried out in a batch or semi-batch reactor. The ''Tendency Modeling'' approach, which consists of the development of an approximate stoichiometric and kinetic model, has been used. An experimental planning method has been utilized as the database for model development. The application of the experimental planning methodology allows comparison between the experimental and model response. The model is then used in an optimization procedure to compute the optimal process. The optimal control problem is converted into a nonlinear programming problem solved using the sequencial quadratic programming procedure coupled with the golden search method. The strategy developed allows simultaneously optimizing the different variables, which may be constrained. The validity of the methodology is illustrated by the determination of the optimal operating conditions of lactic acid production.

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Carbohydrates in alkaline systems. I. Kinetics of the transformation and degradation of D-glucose, D-fructose, and D-mannose in 1 M sodium hydroxide at 22 °C

Cited by 29 publications

References 12 publications

Hydration Free Energies in the FreeSolv Database Calculated with Polarized Iterative Hirshfeld Charges

Hydration Free Energies in the FreeSolv Database Calculated with Polarized Iterative Hirshfeld Charges

Carbohydrates in alkaline systems. II. Kinetics of the transformation and degradation reactions of cellobiose, cellobiulose, and 4-O-β-D-glucopyranosyl-D-mannose in 1 M sodium hydroxide at 22 °C

Modeling and Optimization of Lactic Acid Synthesis by the Alkaline Degradation of Fructose in a Batch Reactor

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