Title:  TES 
CAS Registry Number:  7365-44-8 
CAS Name:  2-[[2-Hydroxy-1,1-bis(hydroxymethyl)ethyl]amino]ethanesulfonic acid 
Additional Names:  N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]taurine;  N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid 
Molecular Formula:  C6H15NO6S 
Molecular Weight:  229.25 
Percent Composition:  C 31.43%, H 6.60%, N 6.11%, O 41.87%, S 13.99% 
Literature References:  One of the zwitterionic amino acids known as "Good" buffers; active in the pH range 6.5 to 8.0.  Prepn: N. E. Good et al., Biochemistry 5, 467 (1966).  Thermodynamic constants:  C. A. Vega, R. G. Bates, Anal. Chem. 48, 1293 (1976).  Effect of temperature and solvent systems on pK2:  H. A. Azab et al., Monatsh. Chem. 125, 233 (1994).  Use as buffer:  F. C. Molinia et al., Reprod. Nutr. Dev. 34, 491 (1994); K. Isobe, H. Nishise, J. Biotechnol. 75, 265 (1999). 
Properties:  Crystals from alcohol/water, mp 226-228°, dec 231°.  pKa of 0.1M soln: (0°) 7.92; (20°) 7.5; (37°) 7.14.  D pKa/°C -0.020. 
Melting point:  mp 226-228° 
pKa:  pKa of 0.1M soln: (0°) 7.92; (20°) 7.5; (37°) 7.14; pKa/°C -0.020 
Use:  Biological buffer.   |