• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.26 no.3
• /
• pp.115-120
• /
• 2016

$CeO_2$ is used as a co-catalyst with $TiO_2$ to improve the catalytic activity of $MnO_x$ and characterization of nano-sized powder is identified with de-NOx efficiency. A comparison between $MnO_x-CeO_2/TiO_2$ and single $CeO_2$ was conducted in terms of microstructural analysis to observe the behavior of $CeO_2$ in the ternary catalyst. The $MnO_x-CeO_2/TiO_2$ catalyst was synthesized by sol-gel method and the average particle size of the single $CeO_2$ is about $285{\mu}m$ due to the low thermal stability, whereas the particle size $MnO_x-CeO_2/TiO_2$ is about 130 nm. The strong interaction between Ce and Ti was identified through the EDS mapping by transmission electron microscopy (TEM). The improvement about 20 % of $de-NO_x$ efficiency is observed in the low-temperature ($150^{\circ}C{\sim}250^{\circ}C$) and vigorous oxygen exchange by well-dispersed $CeO_2$ is the reason of catalytic activity improvement.

• Applied Chemistry for Engineering
• /
• v.9 no.3
• /
• pp.413-418
• /
• 1998

Methoxy polyoxyethylene dodecanoates are a kind of nonionic surfactants obtainable from reaction of fatty acid methyl ester with ethylene oxide utilizing a solid catalyst. Methoxy polyoxyethylene dodecanoates have economical advantage compared with polyoxyethylene dodecyl ethers using fatty alcohol. In this work, the solubilizing capacity concerned with phase behavior of ternary systems composed of nonionic surfactant/water/oil, interfacial tension and detergency at the phase inversion temperature(PIT) were investigated and compared with those of polyoxyethylene dodecyl ethers in order to confirm the applicability of methoxy polyoxyethylene dodecanoates in the detergents. Methoxy polyoxyethylene dodecanoates showed the solubilizing capacity of 10~18% for hexadecane which were about 6% higher than polyoxyethylene dodecyl ethers. At the PIT condition, methoxy polyoxyethylene dodecanoates' interfacial tension were 0.0124~0.0176 dyne/cm while polyoxyethylene dodecyl ethers have the value of 0.013~0.0163 dyne/cm and methoxy polyoxyethylene dodecanoates showed higher detergency of 82.1~83.2% than polyoxyethylene dodecyl ethers of 76.5~77.3%. The good detergency performance of methoxy polyoxyethylene dodecanoates would be due to the higher oil solubilizing power and lower interfacial tension than polyoxyethylene dodecyl ethers at the PIT condition.

• Clean Technology
• /
• v.18 no.3
• /
• pp.325-328
• /
• 2012

The condensation reaction of 9,9'-bis(4-hydroxyphenyl)fluorene with epichlorohydrin to prepare 9,9'-bis[4(glycidyloxy) phenyl]fluorene (2), an important building block for fluorene-containing epoxy polymers, has been studied. The reaction is found to be quite sensitive to several experimental conditions such as reaction temperature and time, added amount of epichlorohydrin, the presence of catalysts and the use of co-solvent. Several conditions for obtaining the best yield in the reaction are: the reaction temperature is below 373 K and the reaction time is shorter than 1.5 h, and the ammonium salts act as a catalyst. Also, the use of ternary solvent (toluene, DMSO, water) has been proved to be crucial to maintain the reaction temperature and for an easy purification. Thus, the reaction proceeds in an environment-friendly manner where the use of reactants and the production of chemical wastes is minimized.