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Catalytic Conversion of Carbohydrates as Renewable Raw Materials to key Platform Chemicals Using Metal Supported Mesoporous Meterials S. Anuradha NCCR, IIT-Madras PART I AN APPROACH TOWARDS FINE AND ORGANIC CHEMICALS BIOETHANOL BIODIESEL FUEL AND ENERGY BIOGAS HYDROGEN BIOMASS BASIC CHEMICALS FINE MATERIALS CHEMICALS AND CHEMICALS BIOPOLYMERS BIOPLASTICS • Biomass resources can be divided into three general categories: Wastes Standing forests Energy crops – herbaceous woody crops Starch crops Sugar crops Oilseed crops • As a source of chemicals, biomass has several intrinsic advantages over fossil mass • It is renewable and flexible through crop switching Platform molecules identified by the US DOE Aspartic acid Glutamic acid Levulinic acid 2-Hydroxypropionic acid 2,5-Furan dicarboxylic acid Glucaric acid Itaconic acid 1,4-Diacids (succinic, fumaric and malic) 3-Hydroxypropionic acid Glycerol Sorbitol Xylitol/arabitol Hydrolysis of Sucrose, Starch and Cellulose • Catalysts: Mineral acids Ion-exchange resins Protonated dY-Zeolites HMM and FSM zeolites • Activation of glycosidic linkage Ayumu Onda,* Takafumi Ochi and Kazumichi Yanagisawa, Green Chem., 2008, 10, 1033–1037 Oxidative Decarboxylation of Glucose • Interest to convert C6 carbohydrates from starch or sucrose into C5 and C4 polyols • Find many applications in food and non-food products. • Dehydroxylation reactions leading to deoxy- products • Catalyst – Ru/anthraquinone-2-sulfonate L. Fabre, P. Gallezot, A. Perrard, J. Catal. 208 (2002) 247. Synthesis of o-Isopropylidene sugar Derivatives • Monosaccharides which contain two sterically adjacent OH groups in the cis-position can be reacted with aldehydes or ketones • Anti-inflammatory and antipyretic active • a central intermediate product for numerous other glucose derivatives • Drugs - 2-deoxy-D-riboseanilide and amiprilose • 1,2:5,6-diacetone-D-glucose can be used as a chiral ligand in complexes which permit enantioselective reactions • Aldoses, Aldosides and ketoses: D-galactose, L- and D-arabinose, fructose, sorbose, D-xylose, D-mannose, D-ribose, D-mannitol • Catalysts: Cupric sulphate in acetone FeCl3 HF/HCOOH in MeOH Zeolite HY VO(OTf)2 SiO2-H2SO4 • Use of Inorganic acids and salt – Require large amount - Disposal • Use of solid catalysts also presents problems as a result of the reactions of caramelisation • The recovery of ion exchangers involves a great deal of expense Schematic representation of reaction pathways for acid-catalyzed hydrolysis and dehydration of polysaccharides to 5-hydroxymethylfurfural (HMF) in a biphasic system. Juben N. Chheda, Yuriy Roma´n-Leshkov and James A. Dumesic, Green Chem., 2007, 9, 342–350 Synthesis of furane derivatives from carbohydrates Schematic diagram for production of liquid alkanes from biomass resources in a biorefinery. Juben N. Chheda, James A. Dumesic, Catal. Today 123 (2007) 59–70 Synthesis of Glucamine • Provides an information about the inhibition of glycosidases • Only carbonyl group of an aldose and ketose is aminated selectively • None of the OH groups is transferred to an amino group • Catalyst: NH3, Ni H.Kelkenberg, Tens.Surf.Det.,25 (1988)1 Hydrogenation of Glucose R. Schoevaart, T. Kieboom, Top. Catal. 27 (2004) 3. Figure 1. Cellulose structure and the potential monomers formed following cleavage of the C-O-C bonds at position a or b. Ning Yan,† Chen Zhao,† Chen Luo,† Paul J. Dyson,‡ Haichao Liu,*,† and Yuan Kou, J. AM. CHEM. SOC. 2006, 128, 8714-8715 Scheme 1. Proposed Reaction Mechanism under Acidic Conditions Scheme 2. Proposed Reaction Mechanism under Neutral and Basic Conditions Schematic representation for catalytic conversion of cellulose into sorbitol Catalyst: Pt/γ-Al2O3 Paresh L. Dhepe Æ Atsushi Fukuoka, Catal Surv Asia (2007) 11:186–191 Use of sorbitol as a precursor to fuels and chemicals • Sorbitol (ca. 800,000 t year-1) - used in food pharmaceutical chemical industries an additives • Catalysts Raney nickel catalysts promoted with electropositive metal atoms such as molybdenum and chromium* Ruthenium supported on acidic Y-zeolite Ruthenium/carbon Ru–Pt/C –rate of epimerization decreases Pt- increases the stability – prevents the formation of oligomeric products Prevents the oxidation of Ruthenium *P. Gallezot, P. Ce´rino, B. Blanc, G. Fle`che, P. Fuertes, J. Catal. 146 (1994) 93. Possible products of oxidation of D-Glucose S. Hermans, M. Devillers, Applied Catalysis A: General 235 (2002) 253–264 • Varieties of high added value chemicals used in detergents & pharmaceuticals (Vitamin C). • Catalyst Hypochlorite mediated by TEMPO (2,2,6,6-tetramethyl-1- piperidinyloxy)* RuCl2(PPh3)3/TEMPO** palladium on charcoal Pd–Bi/C catalysts - (5 wt.% Pd, Bi/Pd = 0.1) Rate of glucose oxidation to gluconate was 20 times higher Selectivity was high on the fresh and recycled catalysts Cocatalyst protecting palladium from over-oxidation because of its stronger affinity for oxygen. *P.L. Bragd, H. van Bekkum, A.C. Besemer, Top. Catal. 27 (2003) 49. **A. Dijksman, A. Marino-Gonzalez, A. Mairata, I. Payeras, I.W.C.E.Arends, R. heldon, J. Am. Chem. Soc. 123 (2001) 6826. Scheme for the mechanism of glucose oxidation on PdBi catalyst* Gold catalysts - active for oxidation with oxygen at basic pH - activity was strongly dependent on particle size The metal-catalyzed oxidation gave comparable selectivity and higher productivity than enzymatic glucose oxidation *M.Besson,F.Lahmer,P.Gallezot, P.Fuertes, G.Fleche,J.Catal. 152 (1995) 116. Oxidation of starch by H2O2 by dry method catalysed by metal phthalocyanine complexes • Active species could be competent to cleave the C2–C3 bond of an anhydroglucose unit of carbohydrate (AGU) having adjacent hydroxyl functions to form aldehyde and carboxyl groups S. L. Kachkarova-Sorokina, P. Gallezot and A. B. Sorokin, C h e m . C ommu n . , 2 0 0 4 , 2 8 4 4. PART- II DEHYDRATION OF FRUCTOSE The Prospect of exciting chemistry of furfural derived compounds such as 5-Hydroxymethyl furfural, 2,5-furan dicarbaldehyde and 2,5-furan-dicarboxylic acid is due to its enormous application • agrochemistry as fungicides, • galvanochemistry as corrosion inhibitors • cosmetic industry and • flavour agents. HMF is a good starting material for the synthesis of precursors of various pharmaceuticals, thermo-resistant polymers and complex macrocycles. The synthesis of HMF is based on the triple dehydration of hexoses. Various substrates can be used: • hexoses • oligo- and polysaccharides • converted industrial wastes Scheme 1: The acid catalysed dehydration of Hexose Scheme 1 • Studies performed by a number of independent scientists demonstrated that the chemistry of the formation of HMF is very complex • It includes a series of side-reactions, which influence strongly on the efficiency of the process. • The dehydration of hexoses is catalysed by protonic acids as well as by Lewis acids. • First syntheses of HMF were catalysed by oxalic acid1 and till now nearly one hundred inorganic and organic compounds were positively qualified as catalysts for the HMF synthesis. • Cottier2 divided catalysts into five groups; they are collected in Table 1. 1. Dull, G. Chem. Ztg. 1895, 19, 216. 2. Cottier, L.; Descotes, G. Trend. Heterocycl. Chem. 1991, 2, 233. • The problem with the efficient preparation of pure 5- hydroxymethylfurfural is still unresolved. • No one has found an inexpensive and easy-to-use mode of the preparation of this compound. • Metal phosphates are well known for their acid properties • They are characterized by polymeric metal(IV) phosphates with layered structures, each layer consisting in a plane of tetravalent metal atoms sandwiched between planes of different hydrogenphosphate/ phosphate species. • Zirconium and Titanium Phosphates3 • Used as acid catalysts in reactions - alcohols dehydration, olefins isomerization and terpenes rearrangements. 3. .Benvenuti,C.Carlini,P.Patrono,A.M.R.Galletti,G.Sbrana,M.A.Massucci,P.Galli, Appl.Catalysis A:193 (2000) 147. Table: 2 Zirconium and Titanium phosphates as well as pyrophosphates used for carbohydrates dehydration. • Batch catalytic experiments were performed under nitrogen atmosphere in a 100 ml magnetically stirred glass vessel, heated with a thermostatted oil bath at 110°C, equipped with a reflux condenser and a vial for sampling the liquid phase. • All the heterogeneous Titanium and Zirconim based catalysts have an ability to dehydrate fructose to HMF in aq. solution without any contemporary rehydration of HMF to levulinic and formic acids • The extent of 2-furaldehyde formation is always limited to less than 1%. • Among the investigated catalyst samples, cubic zirconium pyrophosphate and γ-titanium phosphate offer the best performances, in terms of both activity and selectivity, displaying the highest yields to HMF. Table:3 Fructose and inulin dehydration carried out in aqueous medium in the presence of zirconium-based catalysts(batch experiments)a • Cubic zirconium pyrophosphate, having the highest surface area among all the investigated catalysts (Table 2), can be indifferently obtained from α- and γ-ZrP by thermal treatment at 950°C. • At this temperature most part of the surface Brønsted sites are removed and the resulting cubic pyrophosphate phase is characterized by a large amount of coordinatively unsaturated octahedrical Zr4+ species located on the external faces of the crystallites. • Strong Lewis acid sites would be responsible for significant enhancements of both catalytic activity and selectivity in the fructose dehydration process. Table 4. Fructose and inulin dehydration carried out in aqueous medium in the presence of titanium-based catalysts (batch experiments)a • Cubic titanium pyrophosphate - a low catalytic activity was ascertained. • Lower strength of Lewis acid sites present on the external crystal surface of C-TiP2O7 with respect to those on C-ZrP2O7 • Indirectly confirming the importance of the role played by the Lewis acid strength in this catalytic process • Inulin - promising substitute as cheap raw material for a potential industrial production of HMF • The catalytic activity of various niobium-based catalysts has been preliminarily tested in the fructose dehydration to HMF4. • Catalytic experiments were carried out in batch, under nitrogen, on aq. 6 wt.% fructose solutions in a stirred glass vessel equipped with a condenser and heated with a thermostated oil bath at 110°C. Table: 5 Niobium-based catalytic systems applied for fructose dehydration T.Armaroli, G. Busca, C.Carlini, M.Giuttari, A.M.r.Galletti,G.Sbrana, J.Mol.Catal.A: 151 (2000) 233. Table:6 Fructose dehydration to HMF in the presence of different heterogenous niobium-based catalysts • The Lewis acidity strength is similar in all the catalysts examined - assigned to coordinatively unsaturated Nb5+ sites. • The lower reactivity of HMF towards polymerization processes in the presence of NP catalysts, makes them more promising from applicative point of view. • Catalytic properties of niobic acid (Nb2O5.nH2O) and niobium phosphate (NbOPO4) surfaces were studied.5 • The reaction was performed in a continuous reactor at different temperatures 90–110°C and pressures (from 2 to 6 bar). • The superior catalytic activity of NBP compared to niobic acid was due to its higher intrinsic effective acidity in highly polar and protic media. 5. P.Carniti, A.Gervasini, serena,s.Biella, a.auroux, Catal.Today 118 (2006) 373. Table:7 Surface properties of the NBO samples Selectivity to 5-hydroxymethyl-2-furaldehyde (HMF) vs. fructose conversion for NBO and NBP catalysts at different reaction temperatures (particle size: 20–45 mesh, open symbols; 45–100 mesh, filled symbol). • Besides the evaluation of activity and selectivity, catalyst stability was also explored following the reaction for long time on stream, up to 200–220 h. • Decreasing exponential trend of fructose conversion against reaction time was observed on NBP while a lighter decreasing trend was observed for NBO Deactivation of NBO and NBP as a function of time on stream at 100 °C for the dehydration of fructose in water. • Due to the fast deactivation of a part of the active acid sites of the NBP surface • The loss of activity should be likely due to deposition of insoluble humines or coke on the catalyst surface. •The attempt of obtaining, in a one-pot reaction, FDA from fructose passing through HMF as an intermediate product failed both in water and in a mixed water/methyl isobutyl ketone (MIBK) medium.6 Table:8 Dehydration of fructose to HMF in presence of VOP as heterogeneous catalysta Entry VOP(g) Solvent(ml) Fructose Selectivity to conversion (%) HMF (%) 1. 0.6 H2O (30) 50.1 81.5 2. 0.5 H2O-MIBK (10-30) 49.9 74.2 3. 0.6 H2O-MIBK (5-30) 42.0 70.3 a Reaction conditions: Fructose: 6 mmol; T=80°C;time:2h; nitrogen atmosphere(PN2 = 0.1MPa). 6. C.Carlini,P.Patrono, A.M.R.Galletti,G.Sbrana, V.Zima, Applied Catalysis A: 289 (2005) 197. The modification of the heterogeneous catalysts, obtained by partial substitution of VO3+ with different metal cations (Fe3+, Cr3+, Ga3+, Mg2+, Cu2+ and Pd2+), did not cause any improvement on the performances in this reaction. Table:9 • Direct oxidation of HMF to FDA - VOP and N,N- dimethylformamide (DMF) - 100°C and room pressure of O2. Table:10 HMF oxidation to FDA in DMF by the heterogeneous VOP catalystsa • On the basis of the collected data, DMF resulted in a good solvent for the catalytic oxidation of HMF to FDA and VOP exhibited the best performances at productivity and selectivity level. • HMF is efficiently oxidized to 2,5-diformylfuran using Mn(III)–salen catalysts7 • Sodium hypochlorite - pH 11.3 phosphate buffer–CH2Cl2 biphase system at room temperature. • Yield - 63–89% 7. Ananda S. Amarasekara *, Dalkeith Green, Erinn McMillan, Catal. Communications 9 (2008) 286 Table:11 Yields of 2,5-diformylfuran(2) and reaction conditions All reactions were carried out using 1.0 mmol of HMF (1) in 2.0 mL CH2Cl2 at room temperature. Entries 1–6 using 8.0 mmol NaOCl, entry 7 using 5.0 mmol H2O2, entries 8,9 under 1 atm. of O2 and 2.0 mmol of butyraldehyde was added in entry 8. a Using GC.b Using 1H NMR.c 5-chloromethylfurfural (26%) was the major product. • Chlorination of the hydroxyl group can be completely suppressed by using the pH 11.3 buffered medium. • Economical, high yield room temperature oxidation method • Direct formation of 2,5-furandicarboxylic acid from Fructose8 • Cobalt acetylacetonate encapsulated in sol–gel silica • Bifunctional acidic and redox catalyst • Selectivity: 99% Conversion: 72%. 8Marcelo L. Ribeiro, Ulf Schuchardt, Catalysis Communications 4 (2003) 83–86 Table:12 Yields of 5-hydroxymethyl-2-furfural (2) and of 2,5-furandicarboxylic acid (3) a50 ml of MIBK, 7 g of fructose dissolved in 6 ml deionized water with, 0.1 g of catalyst, 88°C, 8 h. b9.4 ml of MIBK, 0.6 ml deionized water, 0.1 g of catalyst, 40μl of 2, 80°C, 4 h. • The SiO2-gel catalyst is four times more active in the dehydration of fructose to HMF than Co(acac)3.. • This suggests that either another transition state selectivity or different proton transfer rates are operating at the active sites of the heterogeneous catalyst, favouring the formation of HMF. Table:13 Conversions and selectivities in the one- pot synthesis of 2,5-furandicarboxylic acid (3)a a 6 ml deionized water, 0.1 g of fructose, autoclave, 20 bar of synthetic air, 160° C, 65 min. • The evaluation of the two reaction steps in the synthesis of FDA allows the understanding of the catalyst action in both systems. • The SiO2-gel is suitable for the dehydration of fructose, avoiding the formation of by-products. • Activity of free Co(acac)3 depends on the reaction conditions. • The cooperative effect of the acidic matrix and the metal complex occluded therein works properly under the more drastic reaction conditions used and FDA is obtained with high selectivity, without the formation of any by-products. • Lanthanoide(III) ions are found to catalyze the dehydration of D- glucose to yield HMF.9 Catalyst : 2.0 X 10-3 mol dm-3 D-glucose : 0.30 mol dm-3 water : 15 cm3 • The dehydrogenation of D-glucose was carried out by heating a stainless bomb (100 cm3) containing the glass tube at 140°C under 10 atm of nitrogen pressure. 9. Hitoshi Ishida a’ * , Kei-ichi Seri , J. Mol. Catal. A: 112 (1996) L163. Fig. 1. Dependencies of the initial rates of D-glucose dehydration on the lanthanoide(III) ion concentration: LaCl3 ( ■), NdCl3 (●), EuCl3 (▲), DyCI3 (□), and YbCl3, (○). • No further decomposition of HMF takes place at least under the present reaction conditions. • The lanthanoide(III) ions coordinate with D-glucose and act as Lewis acid catalysts for the present reaction because the lanthanoide(III) ions are known to have a high affinity for oxygen atoms. CONCLUSIONS 1. Cubic Zirconium pyrophosphate and γ-Titanium phosphate offer the best performance in terms of both activity and selectivity . 2. The catalytic activity of NP are explained in terms of acidity. The Lewis acidity strength can be assigned to coordinatively unsaturated Nb5+ sites. 3. VOP has a very low surface area(0.8 m2/g). However, high conversion of HMF with low selectivity was found when silica supported VOP catalyst was used. Catalyst Temp.(°C) Time(hr) Conversion Selectivity (%) (%) C-ZrP2O7 100 0.5 44.4 99.8 2.0 52.8 81.4 γ-TiP 100 0.5 36.7 96.1 2 56.6 68.7 NP1 100 2 39.0 67.4 NP2 100 2 33.3 71.9 NBO 100 0.5 30 20 NBP 100 1.0 70 35 VOP 80 2 50.1 81.5 Sio-gel 165(H2O) 1 50 100 88(MIBK/H2O) 8 47 100 4. DMF resulted in a good solvent for the catalytic oxidation of HMF to FDA and VOP exhibited the best performance at productivity and selectivity level. 5. Oxidation of HMF was effected by the metal complexes. 6. Silica-gel is used for the dehydration with good selectivity. 7. Main focus is to prevent further hydrolysis of HMF to levulinic acid and Formic acid.
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