- Zr-MOF-808@MCM-41 catalyzed phosgene-free synthesis of polyurethane precursors
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In this work, a catalytic method is presented for the synthesis of aromatic carbamates from aromatic amines using dimethyl carbonate instead of phosgene as a green and safe reaction process. Microcrystalline Zr-MOF-808 is reported as an active and efficient heterogeneous catalyst for the selective carbamoylation of anilines and industrially relevant aromatic diamines, under mild reaction conditions with near quantitative yields. We have accomplished the selective growth of well-dispersed Zr-MOF-808 nanocrystals within the mesoporous material MCM-41. A superior catalytic performance of the Zr-MOF-808@MCM-41 is demonstrated that together with increased stability stands out as an advantageous heterogeneous catalyst for polyurethane production. In situ FTIR studies have allowed a better understanding of the reaction pathway at the molecular level when the active MOF catalyst is present.
- Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
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- N,N-DISUBSTITUTED LITHIUM BIS(CARBAMOYL)CUPRATE. A CONVENIENT COMPLEX FOR ONE-POT CONVERSIONS OF AMINES TO FORMAMIDES, OXAMIDES, CARBAMATES, AND OXAMIC ACIDS
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Lithium bis(carbamoyl)cuprates (2) were readily derived from secondary amines such as N-methylaniline, N-methylbenzylamine, and diethylamine, under mild carbonylation conditions (0 deg C, 1 atm of carbon monoxide), but diphenylamine and benzylphenylamine were unsuitable as the starting materials.The carbamoylcopper complexes 2 formed in ether were readily converted to the corresponding formamides, oxamides, carbamates, and oxamic acids by the appropriate treatment.The formation and stability of 2 depended much on the solvent used.The higher polarity effect of the solvent (DME, THF, and HMPA) made 2 less stable and caused concomitant evolution of carbon monoxide in further reactions.A palladium catalyst was found to be effective for cross-coupling reactions of 2 with iodobenzene or (E)-β-bromostyrene.
- Wakita, Yoshiaki,Noma, Shun-Ya,Maeda, Minoru,Kojima, Masaharu
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p. 379 - 390
(2007/10/02)
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