The adsorption properties of framework Sn sites in a siliceous zeolite beta were examined by comparing the adsorption of acetonitrile, diethyl ether, and 2-methyl-2-propanol on a Sn-Beta zeolite, a purely siliceous Beta zeolite, and a siliceous Beta zeolite with impregnated SnO2, using temperature-programmed desorption (TPD) and thermogravimetric analysis (TGA). Adsorption stoichiometries close to one molecule per framework Sn site were observed for each of the probe molecules. Although the 1:1 complexes with acetonitrile and diethyl ether decompose reversibly upon mild heating in vacuo, the 1:1 complex formed by 2-methyl-2-propanol underwent dehydration to butene and water over a very narrow temperature range centered at 410 K. FTIR spectra of acetonitrile-d3 at a coverage of one molecule per site exhibit a υ(C–N) stretching frequency at 2312 cm–1 that is not observed with nonframework Sn, providing a convenient method for characterizing the presence of framework Sn sites. Water interacts strongly enough with the Sn sites to prevent adsorption of acetonitrile.

We report a one‐step process for the production of diesel fuel from biomass‐derived 5‐hydroxymethylfurfural (HMF). The reaction proceeds through the sequential transfer hydrogenation and etherification of HMF to 2,5‐bis(alkoxymethyl)furan, a potential biodiesel additive, catalyzed by a Lewis acid zeolite, such as Sn‐Beta or Zr‐Beta. An alcohol is used as a hydrogen donor and as a reactant in etherification. This cascade reaction can selectively produce high yields of the biodiesel additive (>80 % yield) from HMF with the Sn‐Beta catalyst and secondary alcohols, such as 2‐propanol and 2‐butanol.

A route to renewable phthalic anhydride (2-benzofuran-1,3-dione) from biomass-derived furan and maleic anhydride (furan-2,5-dione) is investigated. Furan and maleic anhydride were converted to phthalic anhydride in two reaction steps: Diels-Alder cycloaddition followed by dehydration. Excellent yields for the Diels-Alder reaction between furan and maleic-anhydride were obtained at room temperature and solvent-free conditions (SFC) yielding 96% exo-4,10-dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione (oxanorbornene dicarboxylic anhydride) after 4 h of reaction. It is shown that this reaction is resistant to thermal runaway because of its reversibility and exothermicity. The dehydration of the oxanorbornene was investigated using mixed-sulfonic carboxylic anhydrides in methanesulfonic acid (MSA). An 80% selectivity to phthalic anhydride (87% selectivity to phthalic anhydride and phthalic acid) was obtained after running the reaction for 2 h at 298 K to form a stable intermediate followed by 4 h at 353 K to drive the reaction to completion. The structure of the intermediate was determined. This result is much better than the 11% selectivity obtained in neat MSA using similar reaction conditions. Scheme 1 Route to renewable phthalic anhydride from biomassderived furan and maleic anhydride. † Electronic supplementary information (ESI) available. See

Routes to benzoic acid starting from high-yield, hemicellulose-derived furfural derivative, furan, manufactured from biomass are reported. These routes involve Diels-Alder and dehydration reactions of furan and acrylic acid (or methyl acrylate) in a two-step reaction protocol that minimizes polymerization side reactions associated with furan and acrylic acid. The Diels-Alder reaction of furan and methyl acrylate (or acrylic acid) was run at 298 K catalyzed by Lewis acidic (Hf-, Zr-and Sn-Beta) zeolite catalysts and relatively high turnover frequency (~2 h -1 ) and no side reactions were observed. The dehydration of the oxanorbornene was performed homogeneously at low temperatures (298 to 353 K) in mixtures of methanesulfonic acid and acetic anhydride in 96 % yield. This is compared to only a 1.7 % yield of methyl benzoate obtained for the dehydration of the oxanorbornene in neat methanesulfonic acid. The effect of oxanorbornene concentration and stereochemistry were found not to significantly decrease yield to aromatics while dehydration of the carboxylic acid form of the oxanorbornene led to a drop in selectivity to 43 % at complete conversion in mixtures of methanesulfonic acid and acetic anhydride. This reaction sequence could be an important entry point for selectively directing high-yield, hemicellulose-derived furans to aromatic products used in the existing chemical process industry.

The liquid-phase (69 bar) reaction of 5-hydroxymethylfurfural (HMF) with 2-propanol for production of furanyl ethers was studied at 413 and 453 K over a series of oxide catalysts, including γ-Al 2 O 3 , ZrO 2 , TiO 2 , Al 2 O 3 /SBA-15, ZrO 2 /SBA-15, TiO 2 /SBA-15, H-BEA, and Sn-BEA. The acidity of each of the catalysts was first characterized for Brønsted sites using TPD-TGA of 2-propanamine and for Lewis sites using TPD-TGA of 1-propanol. Catalysts with strong Brønsted acidity (H-BEA and Al 2 O 3 /SBA-15) formed 5-[(1-methylethoxy) methyl]furfural with high selectivities, while materials with Lewis acidity (γ-Al 2 O 3 , ZrO 2 , TiO 2 , and Sn-BEA)or weak Brønsted acidity (ZrO 2 /SBA-15 and TiO 2 /SBA-15) were active for transfer hydrogenation from the alcohol to HMF to produce 2,5-bis(hydroxymethyl)furan, with subsequent reactions to the mono-or diethers. Each of the catalysts was stable under the flow-reactor conditions but the selectivities varied with the particular oxide being investigated.

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Methane can be stored by metal-organic frameworks (MOFs). However, there remain challenges in the implementation of MOFs for adsorbed natural gas (ANG) systems. These challenges include thermal management, storage capacity losses due to MOF packing and densification, and natural gas impurities. In this review, we discuss discoveries about how MOFs can be designed to address these three challenges. For example, Fe(bdp) (bdp 2− = 1,4-benzenedipyrazolate) was discovered to have intrinsic thermal management and released 41% less heat than HKUST-1 (HKUST = Hong Kong University of Science and Technology) during adsorption. Monolithic HKUST-1 was discovered to have a working capacity 259 cm 3 (STP) cm −3 (STP = standard temperature and pressure equivalent volume of methane per volume of the adsorbent material: T = 273.15 K, P = 101.325 kPa), which is a 50% improvement over any other previously reported experimental value and virtually matches the 2012 Department of Energy (Department of Energy = DOE) target of 263 cm 3 (STP) cm −3 after successful packing and densification. In the case of natural gas impurities, higher hydrocarbons and other molecules may poison or block active sites in MOFs, resulting in up to a 50% reduction of the deliverable energy. This reduction can be mitigated by pore engineering. of 9.2 MJ L −1 , which is 70% less than that of gasoline [2,15]. However, carrying an extremely pressurized tank raises safety concerns in vehicles in the case of accidents and has an energy cost associated with compression. Furthermore, CNG, which is the established and predominant technology for NGVs, has a driving range of 350-450 km as compared to 400-600 km for gasoline-powered vehicles [16]. Based on this, there is a need to develop gas storage technology beyond that which is already established in real life applications. Further improvements in natural gas storage for NGV technology should seek to improve driving range to decrease time at the pump and the corresponding number of required tank recharges. Increasing driving range would be helpful to implement the technology in areas where natural gas filling stations are not as abundant. In addition, the CNG tank that holds the fuel takes up cargo space and technological advancements that decrease the volume of the natural gas fuel tank are beneficial. Another approach to store natural gas is LNG, which has an energy density of 22.2 MJ L −1 . Some drawbacks of LNG are the energy and cost associated with liquefaction (−162 • C), which present major technological obstacles [17,18] Lastly natural gas can be stored as ANG. Fairly large volumetric capacities of 4-6 MJ L −1 at pressures of around 35 bar at room temperature for different adsorbents were achieved [19]. The presence of sorbent materials in high pressure tanks reduces the pressure requirement of the tanks, making storage and delivery safer and allows for the use of single-stage compressors. ANG may increase the driving range and decrease the volume required of the fuel tank to achieve a specific driving dis...