105 resultados para decomposition of polymeric precursor method (DPP)


Relevância:

100.00% 100.00%

Publicador:

Resumo:

beta, beta-1, 3-Piopylenedithio-alpha, beta-unsaturated arylketones 2 via chemoselective 1,2-addition with allyl or benzyl Grignard reagents afforded the corresponding carbinols 3 and 4. Catalysed by silica gel, the carbinols 3 and 4 were converted to the beta,gamma-unsaturated arylketones 5, 6. The mechanism and reaction condition were discussed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Two systems of La2-xSrxCuO4+/-lambda and La2-xThxCuO4+/-lambda, mixed oxides with K2NiF4 structure were synthesized. The compositions and structures of the catalysts were characterized by means of XRD, XPS, chemical analysis and so on. The catalytic behavior for the direct decomposition of NO has been investigated. The results show that the catalytic activity is closely related to the oxygen vacancy and lower valence metallic ion in the direct decomposition of NO. The presence of oxygen vacancy is necessary for mixed oxide to have steady activity in NO decomposition.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The nitrogen oxides (NO_x) are serious pollutants in earth's atmosphere in the sensethat they are one of the main sources to cause the acid rain. The removal of NO_x is oneof the key research topics in the protection of environmen.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The mixed oxides LaNiO3, La0.1Sr0.9NiO3, La2NiO4 and LaSrNiO4 were prepared and used as catalysts for the direct decomposition of NO. The catalysts were characterized by means of XRD, XPS, O-2-TPD, NO-TPD and chemical analysis. By comparing the physico-chemical properties and catalytic activity for NO decomposition, a conclusion could be drawn as follows. The direct decomposition of NO over perovskite and related mixed oxide catalysts follows a redox mechanism. The lower valent metal ions Ni2+ and disordered oxygen vacancies seem to be the active sites in the redox process. The oxygen vacancy plays an important role favorable for the adsorption and activation of NO molecules on one hand and on the other hand for increasing the mobility of lattice oxygen which is beneficial to the reproduction of active sites. The presence of oxygen vacancies is one of the indispensable factors to give the mixed oxides a steady activity for NO decomposition.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Nine tetrabasic tungstovanadophosphate heteropoly rare earth element complexes with Dawson structure were synthesized. Their general molecular formulas are K15H4[Ln . (P2W16VO61)(2)] . xH(2)O(Ln = La3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Dy3+, Yb3+). Their structures and properties were investigated by IR, UV, NMR, ESR, XRD, TG-DTA. The results showed that the series of complexes have the same structure as K-16[Ce(P2W17O61)(2)] . 50H(2)O. At the same time, the catalytic activity of the complexes for H2O2-decomposition was also investigated.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A series of perovskite-like mixed oxides La(2-x)Sr(x)MO(4+lambda) (M=Cu, Co,Ni; x=0,1) was prepared and characterized using X-ray powder diffraction. The catalytic properties of these catalysts in NO decomposition were tested. The results showed that LaSrNiO4-lambda with K2NiF4 structure is very active and stable for the decomposition of NO.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The unimolecular charge separations and neutral loss decompositions of the doubly charged ions [C7H7Cl](2+), [C7H6Cl](2+) and [C7H5Cl](2+) produced in the ion source by 70 eV electron impact from 3 chloro-toluenes and benzyl chloride isomers were studied

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mossbauer spectroscopy has been used to investigate the thermal decomposition of the bioinorganic complex of europium and L-glutamine. The Mossbauer parameters can demonstrate that the water molecules in the complex and the chlorine anion in the hydrogen chloride molecule, dissociated from the complex below 200-degrees-C, are not linked directly to the europium atom. The thermal decomposition process of the complex is discussed and a possible coordination model for the europium L-glutamine complex is also proposed on the basis of the thermogravimetric and derivative thermogravimetric curves, and from some evidence obtained from the Mossbauer effects of some decomposition products of the complex.