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Isomerization of Aldo-Pentoses Into Keto-Pentoses Catalyzed by Phosphates

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Isomerization of Aldo-Pentoses Into Keto-Pentoses Catalyzed by Phosphates Electronic Supplementary Material (ESI) for Green Chemistry. This journal is © The Royal Society of Chemistry 2017 Isomerization of aldo-pentoses into keto-pentoses catalyzed by phosphates Irina Delidovich,*a Maria S. Gyngazova,a Nuria Sánchez-Bastardo,b Julia P. Wohland,a Corinna Hoppea and Peter Draboa aChair of Heterogeneous Catalysis and Chemical Technology, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany. E-mail: [email protected] bHigh Pressure Processes Group, Chemical Engineering and Environmental Technology Department, Escuela de Ingenierías Industriales, University of Valladolid, 47011 Valladolid, Spain Fig. 1S Equilibrium constants of the isomerization reactions (left) and equilibrium yields (right) of keto-pentoses as functions of temperature according to the thermodynamic data reported by Tewari et al.1, 2 S1 13CHO CH2OH 13 CHO Glycolaldehyde H C OH Retro aldol + H C OH CH2OH H C OH CHO Isomerization CH2OH Aldol C O CH2OH H C OH C O H C OH Ribose CH OH 13CHO 13 CH2OH 2 + H C OH Dihydroxyacetone CH2OH Glyceraldehyde CH2OH Ribulose 13 CH2OH 13 CH2OH CH2OH 13 13 C O CHO CH2OH C O C O CH2OH 13 H C OH Isomerization C O Retro aldol Aldol H C OH H C OH Dihydroxyacetone + H C OH H C OH H C OH + H C OH H C OH H C OH CH OH CH OH CHO 2 2 CH2OH CH2OH Ribulose Ribulose CH OH Ribose Ribulose 2 Glycolaldehyde Scheme 1S. Isotope label scrambling with D-(1-13C)-ribose as a substrate via consecutive retro aldol and aldol reactions. According to the previously published data, isomerization of glyceraldehyde into dihydroxyacetone (shown in the upper sequence of reactions) is highly favorable in the presence of 3 NaH2PO4+Na2HPO4. S2 Table 1S. Assignments of the resonance signals in the NMR spectra recorded after the isomerization 13 of D-(1- C)-ribose in the presence of NaH2PO4+Na2HPO4 (Fig. 2). F and P denote a furanose and a pyranose cyclic form, respectively. Peak number Chemical shift, ppm Assignment of the resonance signal 1 103.6 C2-β-Xylulose 2 101.6 C1-βF-Ribose 3 97.4 C1-αP-Arabinose 4 96.9 C1-αF-Ribose 5 94.5 C1-βP-Ribose 6 94.2 C1-αP-Ribose 7 72.5 C5-α-Xylulose 8 71.3 C5-β-Ribulose 9 70.5 C5-β-Xylulose 10 67.0 C1-keto-Ribulose 11 66.6 C1-keto-Xylulose 12 63.7 C1-β-Xylulose 13 63.4 C1-α-Ribulose 14 63.2 C1-β-Ribulose 15 63.1 C1-α-Xylulose M 49.5 Methanol (internal standard) S3 Fig. 2S. Linearized dependence of R0, the initial reaction rate of xylose isomerization, on C0, the initial concentration of xylose to determine the reaction order α: lnR0=αlnC0+lnk. Reaction conditions: 2, 5 or 7 wt.% aqueous solution of a substrate, 78°C, 750 rpm, 0.5M NaH2PO4+Na2HPO4. S4 CHO CHO H OH H OH k10 k8 By-product 3 H OH HO H By-product 1 H OH k1 k5 H OH k -1 k-5 CH2OH CH2OH CH OH CH OH Ribose 2 2 Xylose O O k4 H OH HO H k-2 k2 k-7 k7 H OH k-4 H OH CH2OH CH2OH CHO CHO Ribulose Xylulose HO H HO H k11 k k 3 k6 9 By-product 4 H OH HO H By-product 2 k k H OH -3 -6 H OH CH2OH CH2OH Arabinose Lyxose Scheme 2S. Extended reaction network used for kinetic modeling Based on this reaction network, we derive the following system of ordinary differential equations (ODEs): d[Ribose] (k1 k2 k10)[Ribose]k1 [Ribulose]k2 [Arabinose] (1S) dt d[Arabinose] (k2 k3 k11)[Arabinose]k3 [Ribulose]k2 [Ribose] (2S) dt d[Ribulose] (k1 k3 k4)[Ribulose]k1 [Ribose]k4 [Xylulose]k3 [Arabinose] (3S) dt d[Xylulose] (k4 k5 k6)[Xylulose]k4 [Ribulose]k5 [Xylose]k6 [Lyxose] (4S) dt d[Xylose] (k5 k7 k8)[Xylose]k5 [Xylulose]k7 [Lyxose] (5S) dt d[Lyxose] (k6 k7 k9)[Lyxose]k6 [Xylulose]k7 [Xylose] (6S) dt d[By product 1] k8 [Xylose] (7S) dt d[By product 2] k9 [Lyxose] (8S) dt d[By product 3] k10 [Ribose] (9S) dt d[By product 4] k11 [Arabinose] (10S) dt S5 Fig. 3S. Model (solid line) and experimental data (markers) of xylose isomerization in the presence of NaH2PO4+Na2HPO4 at different temperatures. Reaction conditions: 10wt. % of the substrate, 0.5M NaH2PO4+Na2HPO4 at pH 7.5, 750 rpm. S6 Fig. 4S. Model (solid line) and experimental data (markers) of lyxose isomerization in the presence of NaH2PO4+Na2HPO4 at different temperatures. Reaction conditions: 10wt. % of the substrate, 0.5M NaH2PO4+Na2HPO4 at pH 7.5, 750 rpm. S7 Fig. 5S. Model (solid line) and experimental data (markers) of arabinose isomerization in the presence of NaH2PO4+Na2HPO4 at different temperatures. Reaction conditions: 10wt. % of the substrate, 0.5M NaH2PO4+Na2HPO4 at pH 7.5, 750 rpm. S8 Fig. 6S. Model (solid line) and experimental data (markers) of ribose isomerization in the presence of NaH2PO4+Na2HPO4 at different temperatures. Reaction conditions: 10wt. % of the substrate, 0.5M NaH2PO4+Na2HPO4 at pH 7.5, 750 rpm. S9 Table 2S. Effective pre-exponential factors (k0) and activation energies (Ea) obtained for the degradation of pentoses in the presence of NaH2PO4+Na2HPO4. Reaction ln k0 Ea, kJ/mol k 25.6 110 Xylose 8By products k 33.7 131 Lyxose 9By products k 18.5 87 Ribose 10By products k 58.6 206 Arabinose 11By products S10 Table 3S. Comparison of the obtained values for the equilibrium constants (K) with the literature data Reaction Expression for K at 78°C obtained in this K at 78°C, literature K valuea work data 2 Ribose Ribulose K1=k1/k-1 0.66 0.62 2 Ribose Arabinose K2=k2/k-2 1.9 2.2 2 Arabinose Ribulose K3=k3/k-3 0.28 0.29 Ribulose Xylulose K4=k4/k-4 1.6 No data 1 Xylose Xylulose K5=k-5/k5 0.45 0.45 Lyxose Xylulose K6=k-6/k6 0.37 No data b 4 Lyxose Xylose K7=k-7/k7 1.44 1.4 aExpressions were derived in accordance with the reaction network presented in Scheme 2S. bTemperature was not specified in the reference. S11 Estimating accuracy of rate constants Interconversions of ribose-ribulose-arabinose and their equilibrium constants can be presented as follows: k1 Ribose Ribulose K1=[Ribulose]/[Ribose]=k1/k-1 k-1 k2 Ribose Arabinose K2=[Arabinose]/[Ribose]=k2/k-2 k-2 k3 Arabinose Ribulose K =[Ribulose]/[Arabinose]=k /k k 3 3 -3 -3 A certain combination of the equilibrium constants would be equal to 1 because a microscopic reversibility determines the Gibbs energy of the cycles equal to zero: [푅푖푏푢푙표푠푒] [퐴푟푎푏푖푛표푠푒] [푅푖푏표푠푒] 퐾1 푘1 푘 ‒ 3 푘 ‒ 2 (11S) 푌 = 1 = ∙ ∙ = = ∙ ∙ [푅푖푏표푠푒] [푅푖푏푢푙표푠푒] [퐴푟푎푏푖푛표푠푒] 퐾3 ∙ 퐾2 푘 ‒ 1 푘3 푘2 An absolute error of a function Y (x1, x2, …, xn) can be calculated as follows: 푛 ∂푌 (12S) ∆푌 = ∙ ∆푥 ∑|∂푥 푖| 푖 = 1 푖 In our case Y(k1, k-1, k2, k-2, k3, k-3)=(k1·k-3·k-2)/(k-1·k3·k2), as indicated by the equation (11S). Assuming the same relative error for all the obtained rate constants, i.e. Δki/ki is independent of i, the following formula could be derived after differentiation of the Y function: 푛 ∆푌 ∆푘푖 ∆푘푖 (13S) = = 6 푌 ∑ 푘 푘 푖 = 1 푖 푖 As a result, a relative rate of determining the rate constants can be estimated as follows: ∆푘푖 ∆푌 (14S) = ( )/6 푘푖 푌 Thus obtained values are provided in Table 4S. The same approach was used to calculate the relative errors of the rate constants of lyxose-xylulose-xylose interconversions. S12 Table 4S. Estimating relative errors of determining the rate constants (Δki/ki) a b Entry Temperature, °C Ycalc ΔY/Y, % Δki/ki, % Ribose-ribulose-arabinose, Y=(k1·k-3·k-2)/(k-1·k3·k2) 1 56 2.5 150 25 2 64 1.7 70 12 3 70 1.3 30 5 4 78 0.9 10 2 Lyxose-xylulose-xylose, Y=(k-5·k6·k-7)/ (k5·k-6·k7) 5 56 1.4 40 7 6 64 1.5 50 8 7 70 1.6 60 10 8 78 1.8 80 13 a Ycalc denotes Y value calculated according to the equation (11S) based on the determined rate constants; b Relative error of Y was determined as follows: ΔY/Y=(|Ycalc-Ytrue|/Ytrue)·100%, where Ytrue=1, since Gibbs energy of the cycles is equal to zero. S13 Fig. 7S. Parity plot for the substrates and the products. The following data were used for the parity plot: concentrations of all the substrates (xylose, lyxose, arabinose, and ribose) at all the temperatures (56, 64, 70, and 78 °C) as well as concentrations of all the isomeric products upon isomerization of xylose at all the temperatures. S14 Xylose CH OH CH OH O O 2 OH 2 H HO HO O O HO OH HO OH OH OH OH OH H OH OH OH -D-Xylopyranoside -D-Xylopyranoside -D-Xylofuranoside -D-Xylofuranoside 63% 35.5% <1% <1% Lyxose CH OH CH OH HO O HO O 2 OH 2 H HO HO O O HO OH HO OH OH OH OH OH H OH -D-Lyxopyranoside -D-Lyxopyranoside -D-Lyxofuranoside -D-Lyxofuranoside 28% 70% 0.5% 1.5% Ribose CH2OH CH2OH O O O OH O H HO HO OH OH OH H OH OH OH OH OH OH OH OH -D-Ribopyranoside -D-Ribopyranoside -D-Ribofuranoside -D-Ribofuranoside 58.5% 21.5% 13.6% 6.5% Arabinose OH CH OH HO CH2OH 2 H O O O OH O HO HO OH OH OH H OH OH OH OH OH OH -D-Arabinopyranoside -D-Arabinofuranoside -D-Arabinofuranoside 35.5% 2% 2.5% O OHOH HO OH -D-Arabinopyranoside 60% Fig.
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