RAMAN-SPECTRA AND NORMAL VIBRATIONS OF 2-SUBSTITUTED 2,4,4-TRIMETHYLPENTANES (CH3)3CCH2(CH3)2CL, (CH3)3CCH2(CH3)2BR, (CH3)3CCH2 (CH3)25H, (CH3)3CCH2(CH3)2CH3 AS MODEL COMPOUNDS OF A HYDROPHOBIC GROUP OF TRITON-X SURFACTANTS

Raman spectra of 2-chloro-2,4,4-trimethylpentane, 2-bromo-2,4,4-trimethylpentane and 2,2,4,4-tetramethylpentane were measured in the liquid and solid states. Normal coordinate calculations were made on these compounds together with 2,4,4-trimethyl-2-pentanethiol. The analysis has clarified the vibrational modes of the 1,1,3,3-tetramethylbutyl group which corresponds to a hydrophobic group of Triton X surfactants. Molecules of the Cl-, Br- and SH-substituted compounds take the gauche form in the solid state, but take both gauche and trans forms in the liquid state. On the basis of the spectral interpretation of these model compounds, the Raman spectra of Triton X-100 were examined and the bands associated with the hydrophobic 1,1,3,3-tetramethylbutyl group were identified. © 1990.