- Shape-selective Valorization of Biomass-derived Glycolaldehyde using Tin-containing Zeolites
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A highly selective self-condensation of glycolaldehyde to different C4 molecules has been achieved using Lewis acidic stannosilicate catalysts in water at moderate temperatures (40–100 °C). The medium-sized zeolite pores (10-membered ring framework) in Sn-MFI facilitate the formation of tetrose sugars while hindering consecutive aldol reactions leading to hexose sugars. High yields of tetrose sugars (74 %) with minor amounts of vinyl glycolic acid (VGA), an α-hydroxyacid, are obtained using Sn-MFI with selectivities towards C4 products reaching 97 %. Tin catalysts having large pores or no pore structure (Sn-Beta, Sn-MCM-41, Sn-SBA-15, tin chloride) led to lower selectivities for C4 sugars due to formation of hexose sugars. In the case of Sn-Beta, VGA is the main product (30 %), illustrating differences in selectivity of the Sn sites in the different frameworks. Under optimized conditions, GA can undergo further conversion, leading to yields of up to 44 % of VGA using Sn-MFI in water. The use of Sn-MFI offers multiple possibilities for valorization of biomass-derived GA in water under mild conditions selectively producing C4 molecules.
- Tolborg, S?ren,Meier, Sebastian,Saravanamurugan, Shunmugavel,Fristrup, Peter,Taarning, Esben,Sádaba, Irantzu
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p. 3054 - 3061
(2016/11/17)
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- Influence of the Interaction between a Tin Catalyst and an Accelerator on the Formose-Inspired Synthesis of α-Hydroxy-γ-butyrolactone
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In this study, we focused on the tin-catalyzed transformation of formaldehyde into α-hydroxy-γ-butyrolactone (HBL) in the presence of an α-hydroxy carbonyl compound as the accelerator. The screening of various accelerators aided in clarifying the structural prerequisites of the accelerator for the formose-inspired synthesis of HBL. To investigate the influence of the interactions between the tin metal and the accelerator on the catalytic activity, we performed a deuterium-exchange experiment with α-hydroxyacetophenone followed by in situ 119Sn NMR spectroscopy and X-ray absorption fine structure measurements. On the basis of the experimental results, we proposed a reaction mechanism to obtain HBL.
- Yamaguchi, Sho,Matsuo, Takeaki,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
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p. 1386 - 1391
(2016/04/20)
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- Catalytic effect of aluminium chloride on the example of the conversion of sugar model compounds
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Abstract In this work, the catalytic effect of the Bronsted acid hydrochloric acid, the Bronsted base sodium hydroxide and the Lewis acid AlCl3 on the conversion of biomass derived carbohydrates is investigated. On the example of the glycolaldehyde conversion, it is shown that the Lewis acid catalyses the ketol-endiol-tautomerism, the dehydration, the retro-aldol-reaction and the benzilic-acid-rearrangement. The main products are C4- and C6-carbohydrates as well as their secondary products 2-hydroxybut-3-enoic acid 1 and several furans. Under the same reaction conditions hydrochloric acid catalyzes mainly the dehydration and sodium hydroxide the tautomerism and subsequent aldolization.
- Schwiderski, Martin,Kruse, Andrea
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- Mechanistic Insight into a Sugar-Accelerated Tin-Catalyzed Cascade Synthesis of α-Hydroxy-γ-butyrolactone from Formaldehyde
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Applications of the formose reaction, which involves the formation of sugars from formaldehyde, have previously been confined to the selective synthesis of unprotected sugars. Herein, it is demonstrated that α-hydroxy-γ-butyrolactone (HBL), which is one of the most important intermediates in pharmaceutical syntheses, can be produced from paraformaldehyde. In the developed reaction system, homogeneous tin chloride exhibits high catalytic activity and the addition of mono- and disaccharides accelerates the formation of HBL. These observations suggest that the formose reaction may serve as a feasible pathway for the synthesis of important chemicals.
- Yamaguchi, Sho,Matsuo, Takeaki,Motokura, Ken,Sakamoto, Yasuharu,Miyaji, Akimitsu,Baba, Toshihide
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p. 3661 - 3667
(2015/11/17)
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- Mechanistic Studies on the Cascade Conversion of 1,3-Dihydroxyacetone and Formaldehyde into α-Hydroxy-γ-butyrolactone
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Abstract The chemical synthesis of commercially and industrially important products from biomass-derived sugars is absolutely vital to establish biomass utilization as a sustainable alternative source of chemical starting materials. α-Hydroxy-γ-butyrolactone is a useful synthetic intermediate in pharmaceutical chemistry, and so novel biomass-related routes for its production may help to validate this eco-friendly methodology. Herein, we report the specific catalytic activity of homogeneous tin halides to convert the biomass-derived triose sugar 1,3-dihydroxyacetone and formaldehyde into α-hydroxy-γ-butyrolactone. A detailed screening of catalysts showed the suitability of tin catalysts for this reaction system, and isotope experiments using [D2]paraformaldehyde, substrate screening, and time profile measurements allowed us to propose a detailed reaction pathway. In addition, to elucidate the activated species in this cascade reaction, the effect of additional water and the influence of additional Bronsted acids on the reaction preferences for the formation of α-hydroxy-γ-butyrolactone, lactic acid, and vinyl glycolate were investigated. The active form of the Sn catalyst was investigated by 119Sna NMR spectroscopy. Specific catalytic activity of homogeneous tin halides: We present a complete map of the synthetic pathway to α-hydroxy-γ-butyrolactone and related byproducts from 1,3-dihydroxyacetone and formaldehyde. Furthermore, we propose a catalytic mechanism and a valence state of the catalyst in the reaction mixture based on the results of 119Sn NMR spectroscopy.
- Yamaguchi, Sho,Matsuo, Takeaki,Motokura, Ken,Sakamoto, Yasuharu,Miyaji, Akimitsu,Baba, Toshihide
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p. 853 - 860
(2015/06/02)
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- Toward functional polyester building blocks from renewable glycolaldehyde with sn cascade catalysis
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Having been inspired by formose-based hypotheses surrounding the origin of life, we report on a novel catalytic route toward a series of recently discovered four-carbon α-hydroxy acids (AHA) and their esters from accessible and renewable glycolaldehyde (GA) in various solvents. The synthesis route follows a cascade type reaction network, and its mechanism with identification of the rate-determining step was investigated with in situ 13C NMR. The mechanistic understanding led to optimized reaction conditions with higher overall rates of AHA formation by balancing Bronsted and Lewis acid activity, both originating from the tin halide catalyst. An optimal H+/Sn ratio of 3 was identified, and this number was surprisingly irrespective of the Sn oxidation state. Further rate enhancement was accomplished by adding small amounts of water to the reaction mixture, boosting the rate by a factor of 4.5 compared with pure methanol solvent. The cascade reaction selectively yields near 60% methyl-4-methoxy-2- hydroxybutanoate (MMHB). In the optimized rate regime in methanol, an initial TOF of 7.4 molGA molSn-1 h-1 was found. In sterically hindered alcohols (isopropyl alcohol), the rate of AHA formation was even higher, and the corresponding vinyl glycolate esters arose as the main product. Vinyl glycolic acid, 2,4-dihydroxybutanoic acid, and its lactone were formed significantly in nonprotic solvent. The corresponding AHAs have serious potential as building blocks in novel biobased polymers with tunable functionality. The incorporation of vinyl glycolic acid in polylactic acid-based polyesters is illustrated, and postmodification at the vinyl side groups indeed allows access to a range of properties, such as tunable hydrophilicity, which is otherwise difficult to attain for pure poly(l-lactic acid).
- Dusselier, Michiel,Van Wouwe, Pieter,De Smet, Sanne,De Clercq, Rik,Verbelen, Leander,Van Puyvelde, Peter,Du Prez, Filip E.,Sels, Bert F.
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p. 1786 - 1800
(2013/09/02)
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