Acid-Catalyzed Dehydration of Sorbitol to 1,4-Sorbitan
1,4-Sorbitan is a precursor to environmentally benign surfactants, which can be produced from biomass via sorbitol. Acid catalysts convert sorbitol to 1,4-sorbitan; however, successive dehydration of 1,4-sorbitan to isosorbide readily occurs, hampering th
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Acid-Catalyzed Dehydration of Sorbitol to 1,4-Sorbitan
5.1
Introduction
In Chap. 2, the high-yielding one-pot synthesis of glucose from cellulose has been achieved using carbon catalysts and mix-milling pretreatment. In this chapter, the author deals with reaction routes from glucose to useful chemicals in order to emphasize the achievement of this thesis work. Glucose is transformed into a variety of valuable compounds via sorbitol, e.g., medicines, plastics, surfactants, and fuels (Figs. 1.7 and 1.10) [1–3]. Particularly, dehydration of sorbitol provides 1,4-sorbitan (1,4-anhydrosorbitol, Fig. 5.1). 1,4-Sorbitan is a precursor to environmentally benign surfactants [4], which are also used as emulsifying agents in food and pharmaceutical industries [5]. The annual demand of these surfactants is more than 10,000 tons worldwide [2]. 1,4-Sorbitan is produced by the dehydration of sorbitol using acid catalysts or hot-compressed water, in which 1,4-sorbitan readily undergoes further dehydration to give isosorbide (1,4:3,6-dianhydrosorbitol) [6–20]. This hampers the selective and high-yielding synthesis of 1,4-sorbitan from sorbitol. Currently, H2SO4 is employed as a catalyst for sorbitol dehydration in industrial processes, since this low price acid gives 1,4-sorbitan in a relatively high yield (58 %) [6, 7, 10]. Although it is preferable to use heterogeneous catalysts owing to their ease of separation and reuse as well as no corrosivity, further improvement is necessary for replacing H2SO4. Herein, the first purpose of this chapter is selective production of 1,4-sorbitan from sorbitol over solid acids. The second objective is revealing origins of high selectivity of catalysts through mechanistic study since such insights are useful and helpful to design more active catalysts.
© Springer Science+Business Media Singapore 2016 M. Yabushita, A Study on Catalytic Conversion of Non-Food Biomass into Chemicals, Springer Theses, DOI 10.1007/978-981-10-0332-5_5
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5 Acid-Catalyzed Dehydration of Sorbitol to 1,4-Sorbitan
Fig. 5.1 Dehydration of sorbitol
5.2 5.2.1
Experimental Reagents
D(+)-Sorbitol Sulfuric acid
>97.0 %, Tokyo Chemical Industry 96–98 %, super special grade, Wako Pure Chemical Industries JRC-ZRO-2 Zirconium(IV) hydroxide, ZrO1.1(OH)1.8, Catalysis Society of Japan Ammonium sulfate Special grade, Wako Pure Chemical Industries Amberlyst 70 Sulfonic acid cation exchange resin, Organo Nafion SAC-13 Silica-supported fluorinated sulfonic acid polymer, Sigma-Aldrich CBV 780 Proton-type FAU zeolite, Si/Al = 40, Zeolyst, denoted as H-FAU JRC-Z5-90H Proton-type MFI zeolite, Si/Al = 45, Catalysis Society of Japan, denoted as H-MFI JRC-Z-HM90 Proton-type MOR zeolite, Si/Al = 45, Catalysis Society of Japan, denoted as H-MOR Silica-alumina Grade 135, Sigma-Aldrich, denoted as SiO2-Al2O3 1,4-Anhydrosorbitol 97 %, Toronto Research Chemicals, denoted as 1,4-sorbitan D-1,4:3,6-Dianhydrosorbitol >98.0 %, Tokyo Chemical Industry, denoted as isosorbide 1,5-Anhydrosorbitol Toronto Research Chemicals, denoted as 1,5-sor
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