Direct Catalytic Conversion of Biomass-Derived Furan and Ethanol to Ethylbenzene

Abstract

Herein, we report a synthetic strategy to convert biomass-derived unsubstituted furan to aromatics at high selectivity, especially to ethylbenzene via alkylation/Diels-Alder cycloaddition using ethanol, while greatly reducing the formation of the main side product, benzofuran, over zeolite catalysts. Using synchrotron X-ray powder diffraction and first principles calculations, it is shown that the above methodology favors the formation of aromatic products due to readily alkylation of furan by the first ethanol molecule, followed by Diels-Alder cycloaddition with 2 derived ethylene from the second ethanol molecule on a Brønsted acid site in a one pot synthesis. This gives a double promoting effect: alkyl substituent(s) on furan creates steric hindrance to inhibit self-coupling to benzofuran while alkylated furan (diene) undergoes Diels-Alder reaction more favorably due to higher HOMO energy.

Differential Adsorption of l‐ and d‐Lysine on Achiral MFI Zeolites as Determined by Synchrotron X‐Ray Powder Diffraction and Thermogravimetric Analysis

“…Note that as H atoms cannot be directly located by this technique, the rigid framework O atoms are chosen as the crystallographic pointers in measuring the interatomic distances to represent the actual chemical acid‐base information, that is, O framework −H⋅⋅⋅O Lys . The interatomic distances are comparable to those in our previous reports on the study other adsorbate molecules (namely, methanol, ammonia, pyridine, and furans) on H‐ZSM‐5 and H‐USY zeolites. It suggests the formation of acid‐base adducts between Lys and BASs.…”

“…To study the Lys-framework interactions at the atomistic resolution, the closest interatomic distance between the acarboxylate and a-amino groups with the framework Oatoms were analysed. Note that as Ha toms cannot be directly located by this technique,t he rigid framework Oa toms are chosen as the crystallographic pointers in measuring the interatomic distances to represent the actual chemical acidbase information, that is,O framework ÀH···O Lys .T he interatomic distances are comparable to those in our previous reports on the study other adsorbate molecules (namely,m ethanol, [10,11] ammonia, [12] pyridine, [13] and furans [20][21][22] )onH-ZSM-5 and H-USY zeolites.I ts uggests the formation of acid-base adducts between Lysa nd BASs.A ss een in Figure 3, when l-a nd d-Lysa re pre-adsorbed on H-ZSM-5(46) at pH 2.2, the closest interatomic distances observed at Site Iare,for l-Lys:O9 LysI À O18 framework = 2.47(3) and N10 LysI ÀO15 framework = 3.03(3) , and for d-Lys:O 9 LysI ÀO18 framework = 3.02(3) and N10 LysI À O21 framework = 2.74(3) .T he crystallographic O21 framework site is located on the opposite side of the 10-membered ring with respect to O15 framework .W hereas,f or Site II, the closest interatomic distances observed are for l-Lys:O 8 LysII À O7 framework = 2.42(3) and N10 LysII ÀO1 framework = 3.69(3) and for d-Lys:O 8 LysII ÀO7 framework = 2.40(3) and N10 LysII À O5 framework = 3.37(3) .T he closest interatomic distances for l-a nd d-Lys pre-adsorbed on H-ZSM-5 at pH 1.0 are comparable to those pre-adsorbed at pH 2.2. Ther efined adsorbate structures are verified with our DFT calculations (Figure 4).…”

p-Xylene from 2,5-dimethylfuran and acrylic acid using zeolite in a continuous flow system

“…Alternatively, several trials were made for the synthesis of aromatics by Diels-Alder cycloaddition using furans and ethanol (as in situ ethylene source) over zeolite as catalysts in a batch system. [36][37][38][39] However, this approach requires high reaction temperatures to dehydrate ethanol to ethylene and leads to high amounts of by-products. An alternative route for the sustainable production of aromatics from furanics was proposed by replacing ethylene with different dienophiles such as acrylic acid (AA) or maleic anhydride (MA).…”

Study on furfural conversion into aromatics over Zn/HZSM‐5 and Fe/HZSM‐5 catalysts

“…are chosen to be doped into zeolite because these metals are reported to be beneficial for the formation of aromatic compounds such as deoxygenation and hydrogenation reactions. [7][8][9][10][11][12][13][14] In this paper, furfural, a specific compound of the furan family, will be conducted pyrolysis on HZSM-5 catalyst and HZSM-5 catalyst is modified by oxides of zinc (Zn) and iron (Fe). Results are valuated according to conversion into aromatics and aromatic hydrocarbons selectivity such as benzene, toluene,…”

“…If the reaction medium is present with gases such as methane, propylene or methanol, the efficiency of forming hydrocarbons increases, because then the Diels-Alder reaction prevails. [9,13,14] 2. MATERIAL AND METHODS…”