- Degradation of one-side fully-chlorinated 1,2,3,4-tetrachloronaphthalene over Fe-Al composite oxides and its hypothesized reaction mechanism
-
The degradation of 1,2,3,4-tetrachloronaphthalene (CN-27) featuring a one-side fully-chlorinated aromatic ring, was evaluated over three of the prepared rod-like Fe-Al composite oxides (FeAl-1, FeAl-5 and FeAl-10). The results showed that their reactive activities were in the order of FeAl-5 ≈ FeAl-10 ? FeAl-1, which could be attributed to their different pore structural properties and reactive sites caused by the different phase interaction between iron species and the γ-Al2O3. The generation of trichloronaphthalenes (1,2,3-TrCN and 1,2,4-TrCN, i.e. CN-13 and CN-14), dichloronaphthalenes (1,2-DiCN, 1,3-DiCN, 1,4-DiCN and 2,3-DiCN, i.e. CN-3, CN-4, CN-5 and CN-10) and monochloronaphthalenes (1-MoCN and 2-MoCN, i.e. CN-1 and CN-2) suggested the occurrence of successive hydrodechlorination reactions. The amount of CN-14 exceeded that of CN-13 from 71.5% to 77.7% across the three different systems, revealing the preferred occurrence of the first hydrodechlorination step at the β-position. This is dissimilar to the preference at the α-position observed during the dechlorination of octachloronaphthalene (CN-75) over micro/nano Fe3O4. The structural differences between one-side and two-side fully-chlorinated aromatic rings would have a pronounced impact on the reactivity of the chlorine substitution position. The major hydrodechlorination pathway was judged to be CN-27 → CN-14 → CN-4 → CN-2. Additionally, the detected 1,2,3,4,6-pentachloronaphthalene (CN-50) and 1,2,4,6/7-tetrachloronaphthalenes (CN-33/34) suggested the reverse chlorination reaction also happened while the hydrodechlorination reaction was occurring. The C-Cl bond dissociation energies (BDEs) of the parent and daughter polychlorinated naphthalene (PCN) congener were calculated using density functional theory (DFT), to achieve a deeper understanding of a different product yield distribution.
- Liu, Yalu,Lu, Huijie,Pan, Wenxiao,Li, Qianqian,Su, Guijin,Zheng, Minghui,Gao, Lirong,Liu, Guorui,Liu, Wenbin
-
p. 17577 - 17585
(2017/03/31)
-
- PROCESS FOR SYNTHESIS OF AROMATIC COMPOUNDS
-
The present invention refers to a process for preparing a compound of the formula (I) wherein R denotes an organic radical which, together with the two carbon atoms to which it is bonded, forms a carbocyclic or heterocyclic ring; R1, R2, R3 and X, independently, denote hydrogen, halogen, nitro, cyano or an organic radical; or R1 and R2 or R2 and R3, together with the carbon atoms to which they are bonded, form a ring; which comprises exposing a compound of the formula (II) wherein R1, R2, R3 and X are defined as given above and Y and Z, independently, have one of the meanings of X; to an energy source in the presence of a catalyst system.
- -
-
Page/Page column 16
(2008/06/13)
-
- A remarkably simple and efficient benzannulation reaction
-
(Chemical Equation Presented) On a short fuse: Although fused aromatic rings are common structural motifs in natural products, there are relatively few direct methods for the preparation of such systems from acyclic precursors. An atom-transfer radical cyclization carried out under microwave (MW) irradiation has now been developed which gives rapid access to functionalized aromatic compounds from readily available starting materials (see scheme).
- Bull, James A.,Hutchings, Michael G.,Quayle, Peter
-
p. 1869 - 1872
(2008/03/12)
-