Bong Rae Cho

Publications (7)5.86 Total impact

• Article: Effect of structural variation within lipophilic N-(X)sulfonyl carbamoyl lariat ethers on the selectivity and efficiency of competitive alkali metal cation extraction into chloroform.

  Eun Kyung Lee, Bong Rae Cho, Hui Hu, Richard A Bartsch
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  ABSTRACT: Sixteen lipophilic N-(X)sulfonyl carbamoyl lariat ethers with polyether ring sizes of 12-crown-4, 14-crown-4, 15-crown-5, and 18-crown-6 are utilized for competitive alkali metal cation extractions from aqueous solutions into chloroform. Variation of the electron-withdrawing properties of X in the series of methyl, phenyl, 4-nitrophenyl, and trifluoromethyl allows the influence of the acidity of the C(O)NHSO2X group in the side arm upon extraction efficiency and selectivity to be assessed. With X = trifluoromethyl, effective alkali metal cation extractions from acidic, neutral, and basic aqueous solutions are achieved. When the crown ether rings are 14-crown-4, 15-crown-5, and 18-crown-6, selectivities for Li+, Na+, and K+, respectively, are observed. Results are compared with those reported for analogous lariat ether carboxylic acids and phosphonic acid monoethyl esters.
  Analytical Chemistry 06/2002; 74(9):2177-83. · 5.86 Impact Factor
• Article: Reactions of N-halo-N-methylbenzylamines with sodium methoxide-methanol and potassium tert-butoxide-tert-butyl alcohol. Effects of .beta.-carbon substituent and base-solvent system upon the imine-forming transition state

  Richard A. Bartsch, Bong Rae Cho
  04/2002;
• Article: Reactions of N-halobenzylalkylamines with sodium methoxide in methanol

  Bong Rae Cho, Jong Chan Yoon, Richard A. Bartsch
  04/2002;
• Article: Orientation in dehydrohalogenation of 2-halobutanes promoted by 2,6-di-tert-butylpiperidide base

  Richard A. Bartsch, Bong Rae Cho, Jack C. Day
  04/2002;
• Article: Base-promoted, imine-forming 1,2-elimination reactions

  Robert V. Hoffman, Richard A. Bartsch, Bong Rae Cho
  04/2002;
• Article: Eliminations forming carbon-heteroatom multiple bonds. Base-promoted dehydrochlorination of N-chlorobenzylmethylamines

  Richard A. Bartsch, Bong Rae Cho
  04/2002;
• Article: Reactions of N-chlorobenzylmethylamines with secondary amines in acetonitrile. Effect of base strength upon the imine-forming transition state

  Bong Rae Cho, Sung Keon Namgoong, Richard A. Bartsch
  04/2002;