Synthesis And Properties Of Tri - Aniline Derivatives And Their Complexes

The synthesis of Sym-triaminobenzene and its three new derivatives, namely, 6,6’,6’’-（benzene-1,3,5-triyltris（azanylylidene））tris（methanylylidene）)tris（2-met-hoxyph enol）（L₁）,2,2’,2’’-（benzene-1,3,5-triyltris（azanylylidene））-tris（methanylylidene）)triphen ol（L₂） and N,N’,N’’-（benzene-1,3,5-triyl）trinicotinamide（L₃） are investigated in the paper. Four complexes 1-4 are constructed based on compound L1 and four different transition metals. The heterogeneous catalytic activities of complexes 1-4 are also studied.The optimal synthesis route and process are determined after experimental comparison of three different routes. 2-nitrotoluene is adopted as raw material via nitration, oxidation, dehydration and catalytic reduction to obtain the final product. The effect of solvent, raw material ratio, temperature, reaction time and catalyst are investigated to determine the optimal synthesis technology of Sym-triaminobenzene and its three new derivatives. The overall yield of Sym-triaminobenzene is 76.7%, the yield of three derivatives L₁, L₂, L₃ are 93.9%, 93.4%, 75.8% respectively. The purities of all the compounds are more than 97.4%.Four complexes {[Zn₃（L₁）₂]·2H₂O}n（1）、{[Co₃（L₁）₂]·2H₂O}n（2）、{[Cu₃（L₁）₂]·2H₂O}n（3）、 {[Ni₃（L₁）₂]·2H₂O}n（4） have been synthesized by employing L1 and di fferent transition metals, the catalytic properties of which are also investigated. Complexes 1-4 are used as heterogeneous catalysts in the photocatalytic degrada tion of methyl orange aqueous solution and methylene blue aqueous solution, re spectively. It is found that less than 50% methyl orange is degraded when catal yzed by complexes 1 and 2, however, the degradation efficiency is up to 80% when complexes 3 and 4 are adopted as the catalysts. In the photocatalytic deg radation of methylene blue aqueous solution, all the four complexes could catalyze the degradation of about 95% methylene blue, although under different react ion time. The degradation process catalyzed by complex 1 and 4 is much longe r than that catalyzed by complex 2, and copper complex 3 demonstrate the best catalytic activities. Furthermore, the catalytic performances toward Henry reactio ns of complexes 1-4 are also studied. It is found that the catalytic activity of t he copper complex 3 is much better that the other three complexes. The reactio n conversion of 4-nitrobenzaldehyde and nirtomethane in methanol solution attai ns 69.7% under 65 oC in the presence of complex 3 as the catalyst. Different s ubstrates are also employed for comparison in the catalytic reactions. Complex 3 shows much better catalytic activities toward the Henry reaction between 4-nit robenzaldehyde and nirtomethane than 3- and 2- nitrobenzaldehyde, which might be caused by the combination of steric and electronic effect. The experimental r esults also show that complex 3 still retains good catalytic activity after continu ously used for 5 times, and PXRD results indicate no change occurs to the fra mework structure of complex 3, which suggested its potential application as het erogeneous catalyst.The chemical structures of Sym-triaminobenzene and its three new derivatives were confirmed by NMR, IR, HPLC and melting point determination. And the complexes 1-4 were characterized by IR, PXRD, elemental analysis, ICP and TGA.