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Isosorbide is a bio-based functional diol, which is prepared by sequential dehydration of sorbitol and widely used in plasticizers, monomers, solvents or pharmaceuticals. In this study, a variety of acidified Nb2O5catalysts were prepared and used for the sequential dehydration of sorbitol to isosorbide. Acidification can effectively regulate the surface acidity of catalysts, which was measured by pyridine infrared spectroscopy and NH3-TPD analysis. The catalytic performance was related to the surface acidity, including the reaction temperature and the amount of catalysts. After optimization of reaction conditions, the yield of isosorbide reached 84.1% with complete sorbitol conversion during reaction at 150 °C for 3 h over 2 M sulfuric acid modified Nb2O5. Finally, the reaction mechanism regarding the role of Lewis acid sites was discussed. This study is of great significance for further development of an efficient catalytic system for the dehydration of carbohydrates to isosorbide.

The mono-dehydration of sugar alcohols such as d-sorbitol and d-mannitol generates 1,4-sorbitan and 1,4-mannitan, respectively, which are relevant platform molecules for the synthesis of detergents and pharmaceuticals. Most reported catalytic systems provided access to di-dehydrated products, while mono-dehydration required special efforts, particularly regarding selectivity and reaction temperature. A series of functionalized yttrium oxides were prepared via sol-gel synthesis in this work, which not only showed an interesting micropipe-like morphology, but also contained functional components. These materials were investigated as photocatalysts in the dehydration of d-sorbitol and d-mannitol, exhibiting high selectivity to mono-dehydration. The effects of solvent, temperature and catalyst were fully discussed. A catalytic mechanism was proposed based on the experimental results and calculations.

The invention discloses a method for preparation of 1,4-sorbitan by dehydration of D-sorbitol in aqueous medium, wherein one equivalent of water is removed and a cyclization occurs, followed by a treatment with ethanol and isopropanol.

Isosorbide is a versatile chemical intermediate for the production of a variety of drugs, chemicals, and polymers, and its efficient production from natural cellulose is of great significance. In this study, bifunctional catalysts based on niobium phosphates were prepared by a facile hydrothermal method and used for the direct conversion of cellulose to isosorbide under aqueous conditions. NH3-TPD analysis showed that a high acid content existed on the catalyst surface, and pyridine infrared spectroscopic analysis confirmed the presence of both Lewis acid and Br?nsted acid sites, both of which played an important role in the process of carbohydrate conversion. XRD and H2-TPR characterization determined the composition and the hydrogenation centers of the catalyst. An isosorbide yield of 47% could be obtained at 200 °C for 24 h under 3 MPa H2 pressure. The Ni/NbOPO4 bifunctional catalyst retains most of its activity after five consecutive runs with slightly decreased isosorbide yield of 44%. In addition, a possible reaction mechanism was proposed that the synergistic effect of surface acid sites and hydrogenation sites was favorable to enhancing the cascade dehydration and hydrogenation reactions during the conversion of cellulose to isosorbide. This study provides as an efficient strategy for the development of novel multifunctional heterogeneous catalysts for the one-pot valorisation of cellulose. This journal is

Intramolecular dehydration of the biomass-derived hexitols D-sorbitol, D-mannitol, and galactitol was investigated. These reactions were performed in high-temperature water at 523–573 K without added acid catalyst. The rate constants for the dehydration steps in the reaction networks were determined at various reaction temperatures, and the activation energies and pre-exponential factors were calculated from Arrhenius plots. The yield of each product was estimated as a function of reaction time and temperature using the calculated rate constants and activation energies. The maximum yield of each product from the dehydration reactions was predicted over a range of reaction time and temperature, allowing the selective production of these important platform chemicals.

Homogeneous catalytic dehydration of sorbitol to isosorbide has been performed with a series of metal tosylates as catalysts. Conversions up to 100 % and selectivities into isosorbide up to 67% were obtained with Bi(OTs)3. The metals were exchanged with acidic sites of sulfonic resins and the resulting materials were evaluated as heterogeneous catalysts. On the contrary to their homogeneous counter parts, the heterogenized metal sites are non-active. The catalytic activity of the modified resins was systematically diminished in comparison to the native resins. The inhibition is greatly dependent on the nature of the metal and, on a larger extent, of the used resin for the cation exchange.

The confinement of Br?nsted acidic 1-methyl-3-(3-sulfopropyl)-1H-imidazol-3-ium hydrosulfate ([PSMIm][HSO4]) into the channel walls of two-dimensional (2D) COFs using a one-pot self-assembly strategy was achieved by incorporating an imine-linked TPB-DMTP-COF (TPB, triphenylbenzene; DMTP, dimethoxyterephthaldehyde) as the host. An appropriate loading of [PSMIm][HSO4] is crucial for the BIL-COF hybrids to maintain proper geometry in the channel and sufficient acidic sites for the sorbitol substrate and sorbitan intermediate to enter and react. The best yield of isosorbide (97%) from sorbitol to date was obtained in the presence of BIL-COF-30 as the catalyst under optimized conditions. Besides, BIL-COF-30 can be recycled for at least five runs without activity loss.

Production of linear deoxygenated C4 (butanetriols, -diols, and butanols), C5 (pentanetetraols, -triols, -diols, and pentanols), and C6 products (hexanepentaols, -tetraols, -triols, -diols, and hexanols) is achievable by hydrogenolysis of erythritol, xylitol, and sorbitol over supported-bimetallic Rh-ReOx (Re/Rh molar ratio 0.5) catalyst, respectively. After validation of the analytical methodology, the effect of some reaction parameters was studied. In addition to C–O bond cleavage by hydrogenolysis, these polyols can undergo parallel reactions such as epimerization, cyclic dehydration, and C–C bond cleavage. The time courses of each family of linear deoxygenated C4, C5, and C6 products confirmed that the sequence of appearance of the different categories of deoxygenated products followed a multiple sequential deoxygenation pathway. The highest selectivity to a mixture of linear deoxygenated C4, C5, and C6 products at 80percent conversion was favoured under high pressure in the presence of 3.7wt.percentRh-3.5wt.percentReOx/ZrO2 catalysts (54–71percent under 80 bar) at 200 °C.

Poly(methylhydrosiloxane) (PMHS) has been examined for its ability to reduce and subsequently cyclize carbohydrate substrates using catalytic tris(pentafluorophenyl)borane (BCF). The work herein is the first reported example of the direct conversion of monosaccharides to 1,4-anhydro and 2,5-anhydro products utilizing a hydrosiloxane reducing agent. PMHS is produced from waste products of the silicone industry, making it a green alternative to traditional hydrosilane reducing agents. This work thus contributes to the goal of utilizing renewable feedstocks in the production of fine-chemicals.

Mesoporous aluminum-promoted sulfated zirconia (named as mAl-SZ) was directly prepared by grind method, and firstly used to catalyze the solvent-free dehydration of sorbitol to isosorbide. The physicochemical properties of as-prepared catalysts were characterized by FT-IR, TGA, XRD, N2 sorption, NH3-TPD and pyridine-infrared (IR) spectroscopy techniques in order to elucidate the relevance of the catalyst properties and the catalytic performance. It was found that the catalysts prepared by grind method possessed mesoporous structures with high surface area, pure tetragonal phase as well as high sulfur contents, which were advantage to eliminate diffusion limitation and generate abundant acidic sites, especially Br?nsted acidic sites. Furthermore, aluminum promoters could contribute to the considerable increase of the strong acidic sites and ratio of Br?nsted to Lewis acidic sites. Consequently, the mesoporous sulfated zirconia with 6 mol% Al-promoter (6Al-SZ) attained porous structure with improved acidic properties, thus showing the optimal catalytic behavior. The full sorbitol conversion with 73% isosorbide selectivity was achieved under milder conditions (175 °C, 2 h) than those of similar type of catalysts. In addition, the 6Al-SZ exhibited favorable reusability with insignificant drop in isosorbide yield during five reaction cycles.

The present invention relates to a A bactericidal or bacteriostatic composition comprising an acetal or a hexitan ether preferentially of a long-chain alkyl sorbitan, arlitan or mannitan, its use in the treatment or prevention of Gram-positive bacterial infections, its use as a hygiene or dermatological product for external use and a method for disinfecting surfaces.

Biomass contains plentiful hydroxyl groups that lead to an oxygen-rich structure compared to petroleum-based chemicals. Dehydration is the most energy-efficient technique to remove oxygen; however, multiple similar vicinal hydroxyl groups in sugar alcohols impose significant challenges for their selective dehydration. Here, we present a novel strategy to control the etherification site in sugar alcohols by the ketalization of the vicinal-diol group for the highly selective formation of tetrahydrofuran derivatives. A ketone firstly reacts with terminal vicinal hydroxyl groups to form the 1,3-dioxolane structure. This structure of the constrained 1,3-dioxolane ring would improve the accessibility of reactive groups to facilitate intramolecular etherification. As a better leaving group than water, the ketone can also promote intramolecular etherification. Consequently, a range of tetrahydrofuran derivatives are produced in excellent yields with the H-beta zeolite catalyst under mild reaction conditions. This strategy opens up new opportunities for the efficient upgrading of biomass via the modification or protection of hydroxyl groups.

A bactericidal or bacteriostatic composition comprising an isomer mixture of monosaccharide alkyl monoethers or monoacetals, its use in the treatment or prevention of Gram-positive bacterial infections, its use as a hygiene or dermatological product for external use and a method for disinfecting surfaces.

Different commercial sulfonic acid resins (Purolite and Amberlyst type) have been evaluated as acid catalysts for the dehydration of sorbitol to isosorbide. These acidic resins differ in their acid properties, as well as in their thermal and mechanical stabilities. Dehydration of sorbitol has been carried out under solvent-free conditions, by melting sorbitol. At the beginning of reaction, different sorbitans (monodehydration products) were detected, whose dehydration and subsequent cyclization lead to the formation of isosorbide. A maximum yield of 75% is reached after 12?h at 413?K, by using a 5?wt% of Purolite CT269, at atmospheric pressure. This resin maintains its catalytic activity after four runs, and the stability is corroborated by the negligible presence of sulphur species (coming from sulfonic acid leaching) in the reaction medium. This suitable catalytic performance can be explained by its high acid capacity (5.2?meq?g?1) and mechanical and thermal stabilities associated to the macroreticular structure.

The invention discloses a isosorbide of the preparation method. In order to solid sorbitol as raw material, a solid acidic molecular sieve as the catalyst; the mass ratio of the solid sorbitol and molecular sieve 100: 1.0 - 5.0, in pressure is - 0.02 - - 0.06 mpa, temperature is 120 - 200 °C, under the molten state of the catalytic reaction of the 2 - 6 hours, to obtain the isosorbide. After the reaction is finished, the content of the product different sorbitol in 80% or more. The invention of the isosorbide preparation method, the use amount of the catalyst, the catalyst can be recovered for reuse, good reaction selectivity, high yield, after treatment is simple. (by machine translation)

A highly efficient synthesis of isosorbide from sorbitol was developed using Br?nsted acidic ionic liquids (BILs) as the catalyst for the first time. The structure-performance relationship was discussed extensively and a proper value of the Gutmann acceptor number (AN) rather than the inherent of acidity was found to be essential for an optimized yield of isosorbide. In addition, the excellent behavior of preferred BIL-4 in the consecutive recycling tests renders the construction of a continuous process probable. Systematic optimization demonstrated that a yield of 82% of isosorbide with a purity of 99.3% could be reached at balance.

A porous zirconium phosphate catalyst prepared by hydrothermal method was studied for the dehydration of sorbitol to isosorbide under water-free conditions. Various characterization techniques such as XRD, Raman, SEM, NH3-TPD and Pyridine adsorption etc were conducted to determine the textural and acidic properties of the catalyst so as to build the relationship between catalytic performance and catalyst structure. In screening tests with other solid acids, the as-prepared ZrP sample exhibited the promising catalytic behavior for isosorbide production probably assigned to its high surface area, porous structure and the adequate Br?nsted acid sites. Full sorbitol conversion with as high as 73% isosorbide selectivity could be obtained at mild conditions (210?°C, 2?h). Noticeably, the ZrP catalyst could be repeatedly used without any obvious deactivation. Generally, the ZrP catalyst studied in this work possessed a great potentiality as an efficient heterogeneous solid acid catalyst for isosorbide production to diminish the application of homogeneous mineral acid.

Amphiphilic sorbitan acetals have been prepared from sorbitan by acetalisation using linear aliphatic aldehydes or by transacetalisation starting from the corresponding aldehyde diethylacetals. A series of sorbitan acetals has been obtained with 29-81% isolated yields. It has been shown that these sorbitan acetals exist as a mixture of five-membered and six-membered regioisomers. Hydrogenolysis of the mixtures gave the corresponding sorbitan ethers as a mixture of 3 regioisomers with 55-85% isolated yields. A one-pot two-step procedure was also optimized from sorbitan giving similar results. The amphiphilic properties of sorbitan acetals and ethers were evaluated and both families exhibit interesting surfactant properties.

The dehydration of sorbitol to isosorbide over an environmentally benign cellulose-derived solid acid catalyst (CCS) has been investigated in order to develop a sustainable process for isosorbide production. The as-prepared CCS sample contained large amounts of -COOH, phenolic hydroxyl and -SO3H groups and presented satisfactory catalytic activity, isosorbide selectivity and recyclability under water-free conditions. Various methods such as BET, XPS, TG, SEM, FT-IR and pyridine adsorption were conducted to characterize the CCS catalyst in order to elucidate the possible catalyst structure-performance relationship. The results of FT-IR and pyridine adsorption revealed that most of the acid sites contained in CCS catalyst were assigned as strong Br?nsted sites, which were crucial for catalytic sorbitol dehydration into isosorbide. When further compared to the conventional solid acid catalyst (niobic acid), the investigated CCS catalyst in this study was considered as one of the promising alternatives to the highly efficient catalysts for isosorbide production from sorbitol.

PROBLEM TO BE SOLVED: anhydrosugar technique for improving the yield of the alcohol. SOLUTION: a certain aspect of the present invention for the production of alcohol anhydrosugar, SiO 2/Al 2 O 3 ratio is less than 30 400 protophilic type of zeolite beta, zeolite-protophilic MCM-68, CIT-1 type zeolite and proton type of at least 1 is selected from the group consisting of zeolite-containing species in the presence of a dehydration catalyst, and under conditions of pressure and heat, (1) by reacting sugaralcohol anhydrosugar sugaralcohol dianhydro sugaralcohol and to produce at least one of, and (2) causing a mono Anhydrosugar sugaralcohol dianhydro sugaralcohol including at least one of manufacturing. Selected drawing: no (by machine translation)

The present invention relates to a method for producing anhydrosugar alcohol using a two-step hydrothermal reaction. According to the present invention, the method for producing the anhydrosugar alcohol ensures an increase in the yield of the anhydrosugar alcohol without addition of a catalyst or with addition of a small amount of the catalyst, by controlling a reaction temperature in two steps including a primary low-temperature reaction and a secondary high-temperature reaction, in a conversion reaction of sugar alcohol into the anhydrosugar alcohol in the absence of the catalyst or in the presence of a transition metal salt catalyst.(AA) Comparative example 1(BB) Comparative example 2(CC) Example 1(DD) Example 2(EE) Example 3(FF) Example 4COPYRIGHT KIPO 2016

The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of sorbitan oleate. The preparation method comprises: adding a catalyst I, dehydrating solid sorbitol powder to obtain 1,4-sorbitan, adding oleic acid and a catalyst II, and carrying out an esterification reaction of oleic acid and 1,4-sorbitan to obtain sorbitan oleate to obtain sorbitan oleate. According to the method, the phenomenon that sediment is generated during storage of sorbitan oleate is prevented, the appearance and color of sorbitan oleate is prevented, and the exterior quality is effectively improved. Sorbitan oleate obtained from the method is good in emulsifying property and stability, and the application range of sorbitan oleate is extended.

Different (3-mercaptopropyl)trimethoxysilane (MPTS) loadings of sulfonic acid-functionalized micro-bead silica (SA-SiO2) were prepared by silylation and oxidation, and characterized by elemental analysis, SEM, FT-IR, TGA, NH3-TPD, BET N2 adsorption-desorption and 13C NMR CP/MAS. The as-prepared SA-SiO2 showed strong hydrophilic nature and excellent catalytic performance for dehydration of sorbitol to isosorbide. The selectivity to isosorbide is obviously affected by the MPTS loading. Using SA-SiO2 as a solid catalyst with 60.5% MPTS loading, 100% sorbitol conversion and 84% yield of isosorbide are achieved at 120 °C for 10 h under vacuum. The catalyst was reused 10 times without noticeable loss of activity and selectivity.

A readily available ruthenium(II) catalyst was developed for the catalytic hydrogenation of aldehydes with a TON (turnover number) up to 340000. It can be performed without base and solvent, showing highly industrial potential. High chemoselectivity can be achieved in the presence of alkenyl and ketone groups. Further application of this protocol in glucose reduction showed good efficiency. Theoretical studies revealed that the rate-determining step is the hydrogenation step, not the carboxylate-assisted H2 activation step.

Conversion of sorbitol to isosorbide by heterogeneous catalysts is a challenge in biorefinery. Herein, H-beta zeolites with specific Si/Al ratios uniquely give isosorbide in up to 76% yield under mild conditions. Mechanistic study has suggested that acid sites on hydrophobic internal surface are active for this reaction.

A process for preparing cyclic dehydration products from sugar alcohols is described. The process involve using a mixed-acid catalyst reaction mixture containing a reducing acid, having a pKa of about 1.0-1.5, and at least a strong Br?nsted acid or a Lewis acid, having a pKa ≤ 0, or both acids in a solution to dehydrate and ring close said sugar alcohol. Synergistically, the mixed-acid catalysis can produce greater amounts of the desired product at similar levels of compositional accountability than either of the component acid catalysts acting alone.

A process is described for the acid-catalyzed dehydration of a sugar alcohol, wherein the catalyst comprises a water-tolerant Lewis acid. In particular embodiments, the catalyst comprises a homogeneous water-tolerant Lewis acid, especially a homogeneous Lewis acid selected from the group consisting of bismuth (III) triflate, gallium (III) triflate, scandium (III) triflate, aluminum triflate, tin (II) triflate and indium (III) triflate. Such catalysts are effective for dehydrating both of sorbitol and the 1,4-sorbitan dehydration precursor of isosorbide, and bismuth (III) triflate particularly is beneficial for dehydrating mannitol to isomannide.

A process is described for producing an isohexide wherein an hexitol or a combination of hexitols is continuously dehydrated in the presence of an acid catalyst under vacuum using a thin film evaporator.

A number of Br?nsted acids (methanesulfonic acid, p-toluene sulfonic acid, triflic acid, sulfamic acid, citric acid, NaHSO4, and boric acid) and Lewis acids (metal sulfate/triflates) were employed in solvent free dehydration of sorbitol and their influence on anhydroalcohols selectivity has been investigated. The outcome indicated that all the acid catalysts produced first mono-dehydrated product sorbitan followed by second dehydration of 1,4-sorbitan to isosorbide. However, the formation and yield isosorbide were found to depend on the nature of acid sites and their acidic strength. The Br?nsted acids are more efficient to convert sorbitol to isosorbide than Lewis acids. The Br?nsted acids having lower pKa value (i.e. strong acid) exhibited high catalytic activity as well as yield of isosorbide. In the case of Lewis acids, the catalytic activity and selectivity were radically depended on which metal used and their stability during the reaction. The water formed during reaction induced Br?nsted acidity on Lewis acid metal site. The Lewis-assisted Br?nsted acid site enabled high yield of isosorbide up to 70% at moderate temperature (160°C).

Novel polymer-supported Bronsted acid polymer catalysts have been successfully synthesized by radical polymerization, followed by a simple solvothermal route and ion exchange step. The as-synthesized co-polymers were characterized by Elemental Analysis, FT-IR spectroscopy, thermogravimetric analysis and scanning electron microscopy and then were employed as a heterogeneous catalyst for dehydration of sorbitol. Especially, the polymer catalysts have a unique advantage of adjustable Bronsted acidity, and the polymer with 1.82 mmol g-1 of Bronsted acidity was a very efficient catalyst for highly selective dehydration of sorbitol into 1,4-anhydro-d-sorbitol. The dehydration reaction can be completed within 4 h and the selectivity of 1,4-anhydro-d-sorbitol achieved 90%. Moreover, the present catalysts resisted acid-leaching and can be recycled in five consecutive cycles without obvious loss of activity. This journal is

A number of Br?nsted acids (methanesulfonic acid, p-toluene sulfonic acid, triflic acid, sulfamic acid, citric acid, NaHSO4, and boric acid) and Lewis acids (metal sulfate/triflates) were employed in solvent free dehydration of sorbitol and their influence on anhydroalcohols selectivity has been investigated. The outcome indicated that all the acid catalysts produced first mono-dehydrated product sorbitan followed by second dehydration of 1,4-sorbitan to isosorbide. However, the formation and yield isosorbide were found to depend on the nature of acid sites and their acidic strength. The Br?nsted acids are more efficient to convert sorbitol to isosorbide than Lewis acids. The Br?nsted acids having lower pKa value (i.e. strong acid) exhibited high catalytic activity as well as yield of isosorbide. In the case of Lewis acids, the catalytic activity and selectivity were radically depended on which metal used and their stability during the reaction. The water formed during reaction induced Br?nsted acidity on Lewis acid metal site. The Lewis-assisted Br?nsted acid site enabled high yield of isosorbide up to 70% at moderate temperature (160°C).

Abstract Organosulfonic acid functionalized ordered mesoporous silicas with different moieties have been synthesized and used as solid acid catalysts for solvent free dehydration of sorbitol to isosorbide. In screening experiments with distinct solid acids, the arenesulfonic acid functionalized SBA-15 (Ar/SBA-15) showed higher catalyst performance as compared to propyl and fluorosulfonic acid sites. Under optimum reaction condition, Ar/SBA-15 afforded 100% sorbitol conversion with 71% isosorbide selectivity in 2 h at moderate temperature of 170°C. The high activity of catalyst ascribed to its ordered mesoporous structure and ease to access Br?nsted acid sites with high acid strength.

A superhydrophobic mesoporous polymer-based acid catalyst (P-SO3H) was synthesized from solvothermal co-polymerization. The N2 sorption isotherms indicate the rich porosity of P-SO3H, confirmed by the TEM image. The IR spectra indicate the presence of sulfonic acid groups. Interestingly, P-SO3H gives contact angle of water droplet on the sample surface at 154°, suggesting its superhydrophobicity. More importantly, P-SO3H is highly efficient catalyst for dehydration of sorbitol to isosorbide, giving sorbitol conversion higher than 99.0% and isosorbide yield at 87.9%. In addition, P-SO3H exhibits excellent recyclability. After recycles for 5 times, the isosorbide yield is still 77.7%. In contrast, conventional acid catalyst of Amberlyst-15 shows the yield at only 15.4% after recycles for 3 times. The unique catalytic properties are reasonably related to the superhydrophobicity and porosity of P-SO3H. The sample large porosity offers a high degree of the exposed acidic sites to the reactants, and the sample superhydrophobicity would keep the water formed in the dehydration away from the catalyst, promoting the reaction equilibrium. As a result, the catalytic performance in dehydration of sorbitol to isosorbide over the superhydrophobic P-SO3H catalyst is significantly enhanced, compared with conventional acid catalyst of Amberlyst-15.

The effect of pressured carbon dioxide on heterogeneous hydrogenation of benzaldehyde and homogeneous dehydration of sorbitol in water solvent was studied. Initial hydrogenation rates of benzaldehyde over a charcoal-supported palladium catalyst in water at 313 K were enhanced by the addition of carbon dioxide. The initial rate increased with an increase in carbon dioxide pressure and became a maximum at 5 MPa. Dehydration of sorbitol proceeded in water phase at 500 K and initial dehydration rates were enhanced by addition of 30 MPa of carbon dioxide.

Intramolecular dehydration of mannitol in high-temperature liquid water without adding any hazardous acid catalysts and its kinetic analyses were carried out. The dehydration behavior of mannitol was compared with that of sorbitol. 2,5-Anhydromannitol and 1,4-anhydromannitol were major products from the mannitol monomolecular dehydration in contrast with the only major product, 1,4-anhydrosorbitol, from the sorbitol monomolecular dehydration.

A process is disclosed for making dehydration products from an aqueous sugars solution including pentoses, hexoses or both, for example, an aqeous high fructose corn syrup solution, or from an aqueous solution of one or more of the alcohols of such pentoses and hexoses, for example, from an aqueous sorbitol solution, by an acid-catalyzed dehydration using substituted sulfonic acids solubilized in the aqueous sugars or sugar alcohols solution.

A method is disclosed for recovering anhydrosugar alcohols from a mixture comprising closely related compounds, such as sugar alcohols. In the method the mixture is contacted with an adsorbent, whereby the anhydrosugar alcohols are selectively adsorbed. The anhydrosugar alcohols can be recovered by desorption from the adsorbent, using a desorbing solvent.

A crude reaction product includes: (A) about 90 to 100% by weight of a dianhydro sugar alcohol in a solid form and (B) about 0 to about 10% by weight of a reaction byproduct in a solid form. The reaction product is prepared by the steps of (a) preparing a monoanhydro sugar alcohol by reacting a sugar alcohol in the presence of a first cyclization catalyst and (b) preparing a dianhydro sugar alcohol by reacting the monoanhydro sugar alcohol in the presence of a second catalyst.

Methods for the production of dehydrated sugars and derivatives of dehydrated sugars using microwave (MW) irradiation and methods of purifying the same are described. The dehydrated sugars derivatives include 5-hydroxymethyl-2-furfural (HMF) and anhydrosugar alcohols such as sorbitans and isosorbide. The derivatives include HMF ethers, levulinic acid esters, and ether derivatives of the anhydrosugar alcohols. The described methods require lower reaction temperatures and shorter reaction times than similar non microwave mediated reactions known in the art. Typical reaction conditions are 120-210C, and typical reaction times are 30 minutes or less.

A reaction product of the co-dehydration of a sugar alcohol and a reactant polyol having a number average hydroxyl functionality less than 4.0 is disclosed. In some aspects the sugar alcohol comprises mannitol, sorbitol, xylitol, erythritol, or mixtures thereof. In some preferred aspects the sugar alcohol comprises sorbitol. In some aspects the reactant polyol has an average molecular weight of from 40 to 500 Daltons. In some aspects, the reaction product may be suitable for the manufacture of polyisocyanurate foam. In some aspects the reaction product may be mixed with diluent polyols, such as diols, glycols, ethylene glycol, diethylene glycol, dipropylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol and mixtures thereof.

We report a new one-pot synthetic route to tetrahydrofuran derivatives, which were unexpectedly produced under basic conditions by intramolecular etherification of substituted five-membered cyclic carbonates. For alcohols with vicinal hydroxyl groups, and additional OH groups at the β-position, intramolecular etherification leading to 3-hydroxytetrahydrofuran derivatives was observed. These reactions were studied for compounds having from 2 to 6 hydroxyl groups per molecule, and the mechanism was proposed. The developed method provides a new environmentally friendly approach to the synthesis of five-membered cyclic ether derivatives under non-acidic conditions. The Royal Society of Chemistry.

Liquid-phase dehydration of sorbitol has been investigated in wide reaction conditions especially under microwave irradiation in the presence of acidic resin catalysts. From the selectivity for sorbitan and isosorbide, it can be understood that the dehydration is a consecutive reaction (sorbitol to sorbitan, and finally to isosorbide) and that the sorbitan is an intermediate of the dehydration. By using microwave irradiation, the dehydration can be accelerated by around 20-34 times compared with the rate by conventional electric heating at the same temperature, or the reaction temperature can be decreased by around 40 °C for the comparable conversion in a similar reaction time. However, the microwaves do not have noticeable effects on the selectivity for isosorbide or sorbitan. The accelerated dehydration under microwaves is mainly due to decreased activation energy.

Highly concentrated microcrystalline cellulose was directly converted to isosorbide with yields of 35-50%, providing a new approach for producing important fine chemicals from biomass. The Royal Society of Chemistry.

Cellulose is converted into sorbitol and related sugar compounds over water-tolerant and durable carbon-supported Pt catalysts under aqueous hydrogenation conditions. Pre-treatment of cellulose with ball-milling effectively reduces the crystallinity and particle size of cellulose, which results in high conversion of cellulose to sorbitol and mannitol. The selectivity of sorbitol increases by using Cl-free metal precursors in the catalyst preparation as residual Cl on the catalysts promotes the side-reactions. The transformation of cellulose to sorbitol consists of the hydrolysis of cellulose to glucose via water-soluble oligosaccharides and the successive hydrogenation of glucose to sorbitol. The hydrolysis of cellulose is the rate-determining step, and the Pt catalysts promote both the hydrolysis and the hydrogenation steps.

A process is disclosed for converting polysaccharide-containing biomass material to platform chemicals. The process comprises dissolving the polysaccharides in an inorganic molten salt hydrate, converting the polysaccharides to monosaccharides, and converting the monosaccharides to platform chemicals that are easily separable from the inorganic molten salt hydrate. The process comprises a dehydration step in which sugar alcohols are converted to the corresponding (di) anhydro sugars. The dehydration step is carried out in the substantial absence of transition metal salts.

A catalytic system capable of reaching high performance in the hydrogenolysis of cellulose at low reaction temperature and short reaction times has been developed. Therefore, supported noble metal catalysts based on Pt, Pd and Ru have been combined with dilute mineral acids. A broad variable set in terms of type of noble metal, type of acid, acid concentration and reaction time could be evaluated based on chemical interpretation and supported by a Design of Experiment (DoE) approach. The variables significantly influenced conversion of cellulose, product range and selectivity towards sugar alcohol formation. Thus, at 160 °C, above 60% yield in sugars and sugar alcohols with 84% selectivity at a cellulose conversion of 72% could be reached. Besides, glycerol, propylene glycol, ethylene glycol and methanol were formed as additional valuable by-products leading to an overall carbon utilization above 89%. Furthermore, the concept was successfully transferred to real feedstocks in the form of spruce reaching close to 60% conversion in only one hour reaction time.

Methods are described for converting carbohydrates including, e.g., monosaccharides, disaccharides, and polysaccharides in ionic liquids to value-added chemicals including furans, useful as chemical intermediates and/or feedstocks. Fructose is converted to 5-hydroxylmethylfurfural (HMF) in the presence of metal halide and acid catalysts. Glucose is effectively converted to HMF in the presence of chromium chloride catalysts. Yields of up to about 70% are achieved with low levels of impurities such as levulinic acid.

The invention includes a method of dehydration of a sugar using a dehydration catalyst and a co-catalyst within a reactor. A sugar is introduced and H2 is flowed through the reactor at a pressure of less than or equal to about 300 psig to convert at least some of the sugar into an anhydrosugar product. The invention includes a process for producing isosorbide. A starting material comprising sorbitol is flowed into a reactor. H2 is counter flowed through the reactor. The starting material is exposed to a catalyst in the presence of a co-catalyst which comprises at least one metal. The exposing is conducted at a hydrogen pressure of less than or equal to 300 psig within the reactor and the hydrogen removes at least some of any water present during the exposing and inhibits formation of colored byproducts.

A process is described for continuous production of anhydrosugar alcohol by continuous introducing of sugar alcohols and/or monoanhydrosugar alcohols into a reaction vessel and dehydration in the presence of an acid catalyst and solvent in which the resultant reaction product is soluble. Water and the solvent having the dissolved reaction product are each cointinuously removed from the reaction vessel. The reaction product is separated from the removed solvent and the product is optionally purified to a purity of 99.0% the solvent is recycled in the reaction vessel.

An integrated continuous process is disclosed for the manufacture of high purity, polymer grade dianhydro sugar alcohols, such as isosorbide, by the dehydration of corresponding sugar alcohols. The water vapors evolved during the dehydration are used to separate product dianhydro sugar alcohols from the high boiling byproducts in the reaction mass. The product is recovered from the vapor stream as high purity crystals. The high boiling reaction byproducts are recycled.