2026-28-0Relevant academic research and scientific papers
Hydrogenation of 2-ethylanthraquinone with bimetallic monolithic catalysts: An experimental and DFT study
Guo, Yanyan,Dai, Chengna,Lei, Zhigang
, p. 1070 - 1080 (2018)
We studied the hydrogenation of 2-ethylanthraquinone (eAQ) over Pd/SiO2/COR (COR = cordierite) monometallic and Pd-M/SiO2/COR (M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the co-impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd-M (M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts were greatly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd-Ni alloy, Pd-Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield (7.5 g/L) and selectivity (95.3%). Moreover, density functional theory calculations were performed for eAQ adsorption to gain a better mechanistic understanding of the molecule-surface interactions between eAQ and the Pd(1 1 1) or PdM(1 1 1) (M = Ni, Fe, Mn, and Cu) surfaces. It was found that the high activity of the bimetallic Pd-Ni catalyst was a result of strong chemisorption between Pd3Ni1 (1 1 1) and the carbonyl group of eAQ.
Photophysical and photochemical processes of 2-methyl, 2-ethyl, and 2-tert-butylanthracenes on silica gel. A substituent effect study
Dabestani, Reza,Higgin, Jashua,Stephenson, Daniel,Ivanov, Ilia N.,Sigman, Michael E.
, p. 10235 - 10241 (2007/10/03)
PAH are organic pollutants formed and released into the environment by the incomplete combustion of fossil fuel, coal, wood, gas, oil, garbage, tobacco, and charbroiled meat. The photophysics and photochemistry of 2-methylanthracene (2MA), 2-ethylanthracene (2EA), and 2-tert-butylanthracene (2TBA) adsorbed on silica were studied at a silica/air interface. 2MA, 2EA, and 2TBA showed no evidence of ground state pairing even at high surface coverages, and crystallized on the surface at higher surface coverages. The photolysis of 2MA, 2EA, and 2TBA at a silica/air interface proceeded more efficiently than the photolysis of anthracene, to produce the corresponding 9,10-endoperoxides formed by the addition of singlet molecular oxygen (type II) to the ground state molecules. At low surface coverages, no evidence of any dimer was observed in photolyzed 2MA, 2EA, and 2TBA samples. A small amount of dimers (isomeric) were observed at higher surface coverages, suggesting that the crystal forms of these molecules may be involved in the dimerization process. The photolysis rate decreased with increasing surface coverage, due to an inner effect induced by crystal formation. Photolysis rate decreased by an order of magnitude in the presence of 1 monolayer of physisorbed water. Time-resolved transient studies of excited triplet states of 2MA, 2EA, and 2TBA showed that triplet lifetimes were shortened on wet silica. The efficiency of singlet molecular oxygen formation significantly decreased on wet silica. These results indicated that decreased photolysis rate was caused by reduced singlet quantum yield in the presence of physisorbed water.
