RSC Advances p. 43195 - 43203 (2014)
Update date:2022-08-17
Topics:
Ge, Xin
Luo, Chenxi
Qian, Chao
Yu, Zhiping
Chen, Xinzhi
RANEY Ni-catalyzed reductive N-methylation of amines with paraformaldehyde has been investigated. This reaction proceeds in high yield with water as a byproduct. RANEY Ni can be easily recovered and reused with a slight decrease of the yield. Using density functional theory (DFT), the mechanism of RANEY Ni-catalyzed reductive N-methylation is discussed in detail. The reaction pathway involves the addition of amine with formaldehyde, dehydration to form the imine and hydrogenation. In the transition state of hemiaminal dehydration, the C-O bond cleavage of the aromatic amine is more difficult than that of the aliphatic amine. For the aromatic amine, a higher energy barrier must be overcome, which results in a relatively low yield. After addition of amine with formaldehyde and dehydration, imine is obtained and preferred to adsorb on the bridge site of the Ni(111) surface. The preferential pathways of imine hydrogenation involve the pre-adsorbed hydrogen atom attacking the nitrogen atom of the imine. The energy barrier of hydrogenation is much lower than that of addition and dehydration. Thus, the hydrogenation of imine is a relatively rapid reaction step. In the reductive N-methylation of secondary amine, the possible dehydration pathway is different from the one of the primary amine. In the dehydration of the secondary amine, the intermediate hemiaminal is initially adsorbed on the bridge site of the Ni(111) surface, then undergoes C-O bond cleavage, and eventually the hydroxyl is located in the bridge site. With the final hydrogenation, the product is obtained by adsorption on the top site of the Ni(111) surface.
View Morewebsite:http://www.jairadhesales.com
Contact:0091-79-26431096
Address:309 Harikrupa Tower,Nr old Sharda Mandir Char Rasta,Ellisbridge
suzhou chukai pharmateach co,.ltd
Contact:86-512-88812511
Address:Building 3, Wujiang Scientific Innovation Park, 2358 Changan Rd, Wujiang 215200, Jiangsu Province, P. R. China
Contact:+86-21-38228826
Address:Room 505 Building 2, No 3377 Kangxin Highway, Shanghai, Republic China
Contact:+44 7958 511245
Address:PO Box 469, Manchester, UK
Hebei Think-Do Environment Co., Ltd
website:http://www.thinkdo-environment.com
Contact:0311-86510809
Address:No 6, Shilian Middle Street, Circular Chemical Industry Park
Doi:10.1016/j.molstruc.2013.04.040
(2013)Doi:10.1021/ic4002175
(2013)Doi:10.1016/j.jorganchem.2013.06.032
(2013)Doi:10.1021/acs.joc.6b02521
(2017)Doi:10.1016/S0040-4039(98)02019-X
(1998)Doi:10.1039/c39840000029
(1984)