Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 3 de 3
Filter
Add filters








Language
Year range
1.
Journal of Zhejiang University. Science. B ; (12): 378-381, 2005.
Article in English | WPRIM | ID: wpr-249203

ABSTRACT

Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this paper. Raw materials and preparation procedure of the activated carbon have great influences on the compositions and surface structure of platinum/carbon catalysts. Platinum catalysts supported on activated carbon with high purity, high surface area, large pore volume and appropriate pore structure usually exhibit higher activities for hydrogenation of ortho-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene. The catalyst prepared from H(2)PtCl(6) with pH=3 shows greater catalytic performance than those prepared under other conditions.

2.
Journal of Zhejiang University. Science. B ; (12): 584-589, 2005.
Article in English | WPRIM | ID: wpr-249167

ABSTRACT

The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWF(pi-pi) (the relationship between pi-pi overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWF(pi-pi) and BL(N-N) (nitrogen-nitrogen bond lengths) as OWF(pi-pi)=-8.1537+6.5638BL(N-N), can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules' orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).


Subject(s)
Absorption , Azo Compounds , Chemistry , Radiation Effects , Computer Simulation , Electron Transport , Radiation Effects , Light , Models, Chemical , Models, Molecular
3.
Journal of Zhejiang University. Science. B ; (12): 606-610, 2005.
Article in English | WPRIM | ID: wpr-249163

ABSTRACT

The quantum chemical method is employed to study the modified asymmetric allylation of benzaldehyde controlled by diisopropyl D-(-)-tartrate auxiliary. All the structures are optimized completely at the B3LYP/6-31G(d,p) level. The (R)-secondary alcohol can be achieved mainly through a six-membered ring chair-like transition state structure. From the relative reaction rates theory the main product configuration predicted is in agreement with the experiment result.


Subject(s)
Benzaldehydes , Chemistry , Boronic Acids , Chemistry , Carbon , Chemistry , Computer Simulation , Hydrogen , Chemistry , Isomerism , Models, Chemical , Models, Molecular , Molecular Conformation , Phase Transition , Quantum Theory , Solutions
SELECTION OF CITATIONS
SEARCH DETAIL