- ACIDIC ELIMINATION FOR BIO-BASED AROMATICS
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The invention is directed to a process for the preparation of an aromatic product comprising a step b) of contacting one or more intermediate compounds with a further acid to form the aromatic product. The intermediate compounds can be obtained in step a) that includes containing a 7-oxabicyclo[2.2.1]hept-2-ene core structure with an acidic mixture. The amount of acid in step b) is higher than the amount of acid in step a).
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Page/Page column 27
(2021/04/10)
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- DIELS- ALDER RING-OPENING PROCESS
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The invention is directed to a process for the ring-opening of a cycloadduct of formula I obtainable from a reaction of a furanic compound and a diene, said process comprising contacting the cycloadduct with an acidic mixture comprising sulfuric acid and an activating agent to obtain a ring-opened product. The present invention is particularly directed a continuous process.
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Page/Page column 17
(2019/11/19)
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- Selectivity Control in the Tandem Aromatization of Bio-Based Furanics Catalyzed by Solid Acids and Palladium
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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.
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p. 277 - 286
(2017/01/17)
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- IMPROVED PROCESS FOR THE PREPARATION OF A BENZENE COMPOUND
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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.
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Page/Page column 17; 18
(2016/07/05)
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- A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics
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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.
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p. 1368 - 1371
(2016/02/12)
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- Substituted Phthalic Anhydrides from Biobased Furanics: A New Approach to Renewable Aromatics
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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.
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p. 3052 - 3056
(2015/09/28)
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- Renewable production of phthalic anhydride from biomass-derived furan and maleic anhydride
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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.
- Mahmoud, Eyas,Watson, Donald A.,Lobo, Raul F.
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p. 167 - 175
(2014/01/06)
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- Total synthesis of neo-tanshinlactones through a cascade benzannulation-lactonization as the key step
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The cascade annulation-lactonization of phthalides with α-carboxyfurylacrylates in the presence of lithium hexamethyldisilazide (LiHMDS) provides both convergent and semiconvergent regioselective syntheses of neo-tanshinlactones in moderate yields. This methodology also offers an avenue for the direct syntheses of hitherto unreported 6-alkoxycarbonyl-substituted neo-tanshinlactones and their heterocyclic analogues. A new synthesis of 4-alkyl phthalides was developed on the basis of a combination of a Duff reaction and Fuerstner cross-coupling. The cascade benzannulation-lactonization of phthalides with α-carboxyfurylacrylates was employed as the key reaction for the concise synthesis of neo-tanshinlactone. Copyright
- Ghosh, Ketaki,Karmakar, Raju,Mal, Dipakranjan
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p. 4037 - 4046
(2013/07/19)
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- Synthesis of 1,2- and 1,3-dicarboxylic acids via Pd(II)-catalyzed carboxylation of aryl and vinyl C-H bonds
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A Pd(II)-catalyzed reaction protocol for the direct carboxylation of benzoic and phenylacetic acid derivatives to form dicarboxylic acids has been developed. The reaction conditions are also applicable for the carboxylation of vinyl C-H bonds. The first C-H insertion Pd-aryl complex from carboxylic acids has been characterized by X-ray crystallography. Copyright
- Giri, Ramesh,Yu, Jin-Quan
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supporting information; experimental part
p. 14082 - 14083
(2009/03/11)
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- Structural elucidation of an oxidation product of sedimentary porphyrins by one-pot synthesis of 3-methylphthalimide
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One-pot synthesis of 3-methylphthalimide was achieved from 1,2,3-trimethylbenzene. The starting compound was oxidized in two steps to produce methylphthalic acids. The o-isomer was converted into its anhydride, which was subjected to thermal reaction with urea to form 3-methylphthalimide. The product was identical with the reported oxidation product of sedimentary porphyrins.
- Nomoto,Kozono,Mita,Shimoyama
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p. 1975 - 1976
(2007/10/03)
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- Chemical oxidation of an anticonvulsant N-(5'-methylisoxazol-3-yl) 2,6- dimethylbenzamide (D2916)
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The new anticonvulsant N-(5'-methylisoxazol-3-yl)-2,6-dimethylbeazamide (D2916), which presents two kinds of methyl groups which could be oxidized, was submitted to various chemical oxidizing agents. Several sites and degrees of oxidation were observed. The main oxidized site was the arylmethyl group without cleavage of the isoxazole ring, leading via carboxylic acid and primary alcohol intermediates to phthalimide and lactame derivatives. In no case was the methyl group of the isoxazole moiety hydroxylated.
- Adolphe-Pierre,Menager,Tombret,Verite,Lepage,Lafont
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p. 513 - 518
(2007/10/03)
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- Condensed pyridazinyl guanidines, their production and use
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Pyridazinyl guanidines of the formula: wherein ring A is a benzene ring or a nitrogen-containing 6-membered aromatic ring, each of which may be substituted; and R1is an aromatic ring group which may be substituted, or a salt thereof, which have activity for inhibiting Na-H exchange and are useful as a prophylactic/therapeutic agent for ischemic cardiovascular diseases such as myocardial infarction and arrythmia.
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- Synthesis and Mass Spectrometric Fragmentation of Dihydroisoindole Derivatives
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C-8-substituted N-methyl-1,2,3,4-tetrahydroisoquinoline radical cations lose the complete substituent in a one step reaction giving rise to an unexpected ion at m/z 146, which is probably identical with the dihydroisoindolylmethyl-cation A.The dihydroisoindoles 1, 10, and 16 were prepared as potentially alternative precursors of ion A.Hovever, the ion at m/z 146 in their EI mass spectra is of very low intensity, so CID-experiments for structural comparison could not be performed.The electron impact induced fragmentations of 1, 10, and 16 are discussed.
- Knefeli, Frank,Mayer, Klaus K.,Wiegrebe, Wolfgang
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p. 419 - 426
(2007/10/02)
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- Direct spectroscopic study of unstable molecules with silicon-oxygen multiple bonds: Low temperature matrix stabilization of (CH3)2Si=O and (CD3)2Si=O in the gas phase
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To continue the IR spectroscopic investigations of intermediates with doublebonded silicon, the silanones (CH3)2Si=O and (CD3)2Si=O have been generated by vacuum pyrolysis of the corresponding 6-oxa-3-silabicyclohexanes and of Diels-Alder adducts of silapyranes with maleic anhydride.The above silanones have first been stabilized from the gas phase in argon matrices at 12 K and studied by IR spectroscopy.Using the dependence of the spectra on temperature and pressure in the pyrolysis zone or in warming-up experiments (to 35-40 K) the following vibrational bands of silanones have been revealed: (CH3)2Si=O 1244, 1240, 1210, 822, 798, 770, 657 cm-1; (CD3)2Si=O 1215, 1032, 1007, 995, 712, 685, 674 cm-1.The limits of thermal ( 850 deg C) and kinetic (5 x 10E-4 torr) stability of dimethylsilanone were determined.By comparison of frequencies found with computed values the band 1210 cm-1 in (CH3)2Si=O (1215 cm-1 in (CD3)2Si=O) was assigned to a Si=O streching vibration.This frequency as well as the calculated force constant (8.32 mdyn/Angstroem) and order (1.45) of the Si=O bond are considered as evidence of significant double bonding in dimethylsilanone.
- Khabashesku, V. N.,Kerzina, Z. A.,Baskir, E. G.,Maltsev, A. K.,Nefedov, O. M.
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p. 277 - 294
(2007/10/02)
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- Process for producing substituted phthalic acid compounds
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A process for producing a substituted phthalic acid which comprises heating a substituted tetrahydrophthalic acid compound having a substituent in at least one of the 3-, 4-, 5- and 6-positions in the presence of sulfur to dehydrogenate it, and heat-treating the product in the presence of water optionally together with an organic solvent. As required, the heat-treated product is dehydrocyclized to form a substituted phthalic acid anhydride.
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- Ashless additives for lubricating compositions
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Superior ashless additives for lubricants are prepared by a process comprising first introducing a petroleum sulfonic acid and a polyamine to a reaction zone and subsequently introducing a cyclic anhydride of a dicarboxylic acid into the reaction zone. In another embodiment, the solids content of the additives is reduced to acceptable levels by removal of free SO2 from the petroleum sulfonic acid prior to preparing the additive. Lubricating oil compositions containing these ashless additives are also provided.
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