Acid soap and phase behavior of stearic acid and triethanolamine stearate.
Crystals of partially neutralized stearic acid with triethanolamine (TEA) were prepared by mixing these two materials above 80 degrees C and then cooling. The crystalline composition and the structure and melting behavior of the resultant products were characterized with small-angle and wide-angle X-ray diffraction, thermal analysis, microscopy, and infrared spectroscopy. It was discovered that an acid-soap complex of 2:1 fixed stoichiometric ratio exists between stearic acid and TEA stearate. A binary phase diagram of stearic acid and TEA soap is built based on the experimental results; this is the first published record of a binary phase diagram for amine-based soap. Its behavior is significantly different from that of binary systems of fatty acid and alkali soap.
Zhu
S
S
Corporate Research, Unilever R & D, Colworth Lab, Bedford, MK44 1LQ, UK. shiping.zhu@unilever.com
Heppenstall-Butler
M
M
Butler
M F
MF
Pudney
P D A
PD
Ferdinando
D
D
Mutch
K J
KJ
D000143:Acids / Q000737:chemistry; D003460:Crystallization; D018360:Crystallography, X-Ray; D004983:Ethanolamines / Q000737:chemistry*; D006358:Hot Temperature; D007259:Infrared Rays; D012915:Soaps / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013229:Stearic Acids / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
D000143:Acids; D004983:Ethanolamines; D012915:Soaps; D013229:Stearic Acids; C031183:stearic acid; C009546:triethanolamine