Hyun Soo Yang

Synthesis of Maleic and Phthalic Anhydrides from the Mixture of Cyclopentene and 1-Pentene

The selective oxidations of cyclopentene, 1-pentene, and their mixture to maleic and phthalic anhydrides have been studied to gain information on the total utilization of olefins of C5-fraction. The highest selectivities for maleic anhydride, a single major organic product, in individual oxidations of cyclopentene and 1-pentene were obtained at complete or almost complete conversion, and then the main byproduct was phthalic anhydride. The cooxidation of the mixture of cyclopentene and 1-pentene at ca. 100% conversion, which was selected as optimized condition, gave no interaction between cyclopentene and 1-pentene. This result indicates that two reactants can be simultaneously utilized at one oxidation unit process. In contrast, the cooxidation at low degrees of conversion gave some interaction. It was only related to the slightly stronger adsorption of cyclopentene as compared to 1-pentene.

REMOVAL OF METAL IONS BY ULTRAFILTRATION OF A MICELLAR SOLUTION CONTAINING ANIONIC SURFACTANT

Heavy metals in wastewater were removed by ultrafiltration of a micellar solution containing surfactant such as sodium dodecyl sulfate. Experimental results showed that permeate flux was primarily controlled by the operating parameters such as transmembrane pressure difference, flow rate and feed concentration. The average permeate flux increased at a higher transmembrane pressure, feed velocity, and at a lower solution concentration. The transmembrane pressure had a relatively small effect on metal removal whereas the level of surfactant-to-metal ratio (S/M) had a substantial effect. The optimal ratio of S/M for a best removal of metal ions was measured around 5 and 8 in the presence of sodium dodecyl sulfate, and the affinity resulted in the order of Cr> Co> Ni> Mg.

Ozonolysis of cyclododecene

Ozonolysis of cyclododecene was carried out to produce an w-formyl carboxylic acid (12-oxododecanoic acid) which is derived from zwitterion and aldehyde moiety that are formed during the reaction. The ozonolysis was performed to examine the product distribution under such reaction variables as temperature, kinds of solvent, and presence of catalyst. The yield of polymeric ozonide, which is undesirable product, was measured to be dominantly 86% without pyridine catalyst, whereas, only 10.25% with the catalyst. The optimum reaction condition was to be in MC (methylene chloride) solvent, and in the presence of equimolar olefin and pyridine catalyst at O°C, at which the yields of polymeric ozonide, 1,12-dodecanedialdehyde, 1,12-dodecanedicarboxylic acid, and 12-oxo-dodecanoic acid were 10.25%, 26.72%, 26.31%, and 36.72%, respectively.

Effect of phase transfer catalyst on CO substitution of Mo(CO)6

The effect of Q+ OH- was studied, which is formed in NaOH solution used for anion exchange with PTC, on CO substitution of molybdenum hexacarbonyl complex by strong electron donating ligand, 2,2’-bipyridine. The change of product yield was discussed according to the amount and types of solvent and PTC, their compositions, reaction temperature and time, and different cation and anion of PTC.