SYNTHESIS, CHARACTERIZATION, AND SURFACE-ACTIVITY OF SURFACTANTS DERIVED FROM NONYLPHENOL, ETHYLENE-OXIDE AND CARBON-DIOXIDE

The synthesis of the nonylphenol poly(ethylene carbonate) surfactants derived from nonylphenol (NP), carbon dioxide and ethylene oxide (EO) were carried out with high yields in the presence of alkali metal salt s (K2CO3, Na2CO3, K2SnO3 and zinc glutamate) as base catalysts. The sy nthesis reactions were carried out in a stainless-steel reactor in the temperature range of 150-200 degrees C under an initial pressure of 8 00 psi, with an initial molar ratio of CO2/EO = 0.21, catalyst concent ration of 1 x 10(-3) M for a 24 h-period. The surfactants were charact erized by FT-IR and by H-NMR. The percentages of carbon dioxide incorp oration were between 7 and 16% indicating that the activation of CO2 i s a rather difficult process under the catalytic conditions used (175- 200 degrees C and 800 psi of final pressure). It was found that the mo st probable mechanism for the synthesis of the surfactants occurs in t wo steps. The first reaction involves the role of the base as a cataly st for the formation of the cyclic ethylene carbonate from CO2 and eth ylene oxide. The next step is the reaction of the nonylphenol in the p resence of cyclic ethylene carbonate and ethylene oxide to generate th e surface active compounds. This mechanism indicates that for each mol of carbon dioxide incorporated, one mol of EO has to be added. The CM C values of the surfactants decrease (from 200 to 100 mM) with the inc rease in the molar ratio CO2/EO (from 0.08 to 0.3) which can be attrib utted to a decrease in the hydrophilic character of the surfactant hea ds due to the addition of carbonate groups (-O-C(=O)-O-) to the ethoxy lated chains (between 1 to 3 moles).