- Selectivity Control in the Tandem Aromatization of Bio-Based Furanics Catalyzed by Solid Acids and Palladium
-
Bio-based furanics can be aromatized efficiently by sequential Diels–Alder (DA) addition and hydrogenation steps followed by tandem catalytic aromatization. With a combination of zeolite H-Y and Pd/C, the hydrogenated DA adduct of 2-methylfuran and maleic anhydride can thus be aromatized in the liquid phase and, to a certain extent, decarboxylated to give high yields of the aromatic products 3-methylphthalic anhydride and o- and m-toluic acid. Here, it is shown that a variation in the acidity and textural properties of the solid acid as well as bifunctionality offers a handle on selectivity toward aromatic products. The zeolite component was found to dominate selectivity. Indeed, a linear correlation is found between 3-methylphthalic anhydride yield and the product of (strong acid/total acidity) and mesopore volume of H-Y, highlighting the need for balanced catalyst acidity and porosity. The efficient coupling of the dehydration and dehydrogenation steps by varying the zeolite-to-Pd/C ratio allowed the competitive decarboxylation reaction to be effectively suppressed, which led to an improved 3-methylphthalic anhydride/total aromatics selectivity ratio of 80 % (89 % total aromatics yield). The incorporation of Pd nanoparticles in close proximity to the acid sites in bifunctional Pd/H-Y catalysts also afforded a flexible means to control aromatic products selectivity, as further demonstrated in the aromatization of hydrogenated DA adducts from other diene/dienophile combinations.
- Genuino, Homer C.,Thiyagarajan, Shanmugam,van der Waal, Jan C.,de Jong, Ed,van Haveren, Jacco,van Es, Daan S.,Weckhuysen, Bert M.,Bruijnincx, Pieter C. A.
-
p. 277 - 286
(2017/01/17)
-
- IMPROVED PROCESS FOR THE PREPARATION OF A BENZENE COMPOUND
-
A benzene compound is prepared in a process, which comprises (i) reacting a furan compound of formula (I): wherein R1 and R2 are the same or different and independently selected from the group consisting of hydrogen, alkyl, aralkyl, -CHO, -CH2OR3, -CH(OR4 )(OR5), -COOR6, wherein R3, R4 and R5 are the same or different and are independently selected from the group consisting of hydrogen, alkyl, aryl, alkaryl, aralkyl, alkylcarbonyl and arylcarbonyl, or wherein R4 and R5 together form an alkylene group, and wherein R6 is selected from the group consisting of hydrogen, alkyl and aryl, with an olefin of the formula (II): R7-CH=CH-R8; wherein R7 and R8 are the same or different and are independently selected from the group consisting of hydrogen, sulfonate, -CN, -CHO, and -COOR9, wherein R9 is selected from the group consisting of hydrogen, and an alkyl group, or R7 and R8 together form a –C(O)-O-(O)C- group or a –C(O)-NR10-C(O)- group, wherein R10 represents hydrogen, an aliphatic or an aromatic group, to produce an unsaturated bicyclic ether having an unsaturated carbon-carbon bond; (ii) hydrogenating the unsaturated carbon-carbon bond in the unsaturated bicyclic ether to produce a saturated bicyclic ether; and (iii) dehydrating and aromatizing the saturated bicyclic ether to produce the benzene compound.
- -
-
Page/Page column 16
(2016/07/05)
-
- A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics
-
Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80 % selectivity in a solid-phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst. Hydrogenated adducts from diene/dienophile combinations of (methylated) furans with maleic anhydride are efficiently converted into renewable aromatics with this new route. The zeolite H-Y was found to perform the best and can be easily reused after calcination. Just heat and tumble: Furanics-derived hydrogenated Diels-Alder adducts can be conveniently converted, over acidic zeolites, into renewable aromatics using a solid-phase conversion strategy. The zeolite H-Y was found to perform the best and can be easily reused after calcination.
- Thiyagarajan, Shanmugam,Genuino, Homer C.,Van Der Waal, Jan C.,De Jong, Ed,Weckhuysen, Bert M.,Van Haveren, Jacco,Bruijnincx, Pieter C. A.,Van Es, Daan S.
-
supporting information
p. 1368 - 1371
(2016/02/12)
-
- Substituted Phthalic Anhydrides from Biobased Furanics: A New Approach to Renewable Aromatics
-
A novel route for the production of renewable aromatic chemicals, particularly substituted phthalic acid anhydrides, is presented. The classical two-step approach to furanics-derived aromatics via Diels-Alder (DA) aromatization has been modified into a three-step procedure to address the general issue of the reversible nature of the intermediate DA addition step. The new sequence involves DA addition, followed by a mild hydrogenation step to obtain a stable oxanorbornane intermediate in high yield and purity. Subsequent one-pot, liquid-phase dehydration and dehydrogenation of the hydrogenated adduct using a physical mixture of acidic zeolites or resins in combination with metal on a carbon support then allows aromatization with yields as high as 84 % of total aromatics under relatively mild conditions. The mechanism of the final aromatization reaction step unexpectedly involves a lactone as primary intermediate.
- Thiyagarajan, Shanmugam,Genuino, Homer C.,?liwa, Micha?,Van Der Waal, Jan C.,De Jong, Ed,Van Haveren, Jacco,Weckhuysen, Bert M.,Bruijnincx, Pieter C. A.,Van Es, Daan S.
-
p. 3052 - 3056
(2015/09/28)
-