- SILICA-BASED ZINC CATALYSTS. THEIR PREPARATION AND USE IN THE ALKOXYCARBONYLATION OF AMINES
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The present invention relates to silica-based heterogeneous zinc compounds which are suitable as catalysts in the reaction of amines with dialkyl carbonates to produce carbamates. The catalysts have the formula [SiO2]-CH2-CHR-X-COOZn[Y], wherein [SiO2] represents a silica carrier selected from the group consisting of ordered mesoporous silica and irregular amorphous narrow pore silica, R represents a moiety selected from the group consisting of hydrogen, -CH3, and -CH2CH3, preferably hydrogen, X is an aliphatic chain of 2 to 11 carbon atoms that optionally comprises ether moieties and [Y] represents a mono anion. The invention is also directed towards a method for the preparation of the aforementioned compounds and towards method for the alkoxycarbonylation of amines.
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Page/Page column 22-28
(2018/12/13)
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- Full N,N-Methylation of 4,4′-Methylenedianiline with Dimethyl Carbonate: A Feasible Access to 4,4′-Methylene bis(N,N-Dimethylaniline)
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The full N,N-methylation of 4,4′-methylenedianiline (MDA) with dimethyl carbonate (DMC) was investigated. The yield of the major product 4,4′-methylene bis(N,N-dimethylaniline) (MBDMA) reached as high as 97% over NaY catalyst at 190°C for 6 h. The catalyst could be used for two more times with acceptable MBDMA yields higher than 90%. The main by-products were identified as three N-methylated derivatives. Surprisingly, the formation of the N-methoxycarbonylation product was extremely restrained, which could be produced in high yields of 98% on zinc acetate catalyst. Furthermore, the reaction pathway to the major product MBDMA was proposed. Finally, a feasible synthetic route of 4,4′-methylene bis(N,N-dimethylaniline) (MBDMA) was established, featuring a high yield, mild reaction conditions, and simple operations.
- Qiu, Zegang,Wang, Kunjie,Li, Zhiqin,Li, Tao,Bai, Jinhao,Yin, Chanjuan,Ye, Xiushen,Liu, Haining
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- Benzotriazole Mediated Synthesis of Methylenebisanilines
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Methylenebisanilines and methylenebis(N,N-dialkylaniline)s are prepared by the reactions of 1-hydroxymethylbenzotriazole with anilines and with N,N-dialkylanilines under acidic conditions.Isolation of the intermediate 4-(benzotriazol-1-ylmethyl)anilines and the N,N-dialkyl analogues and their reactions with anilines allow the efficient preparation of both symmetrical and unsymmetrical members of both product classes.
- Katritzky, Alan R.,Lan, Xiangfu,Lam, Jamshed N.
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p. 341 - 346
(2007/10/02)
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- Alkylidene Transfer from Monochloroalkylmercury(II) Compounds to Aromatic Amines; Selective C-Alkylation
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αα-Diarylalkane derivatives have been synthesized from monochloroalkylmercury(II) compounds in a noncarbenoid alkylidene transfer reaction which takes place selectively on the aromatic ring.A mechanism is suggested for this process.Intermediate products are prepared by alternative routes to ascertain their participation in the course of the reaction.As a consequence, two different aryl groups can be successively incorporated into the alkane molecule.
- Barluenga, Jose,Campos, Pedro J.,Roy, Miguel A.,Asensio, Gregorio
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p. 1420 - 1426
(2007/10/02)
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