Surfactants (R
iOC
3H
6SO
3Na, R
iCOOC
3H
6SO
3Na) having propane sulfonate group were prepared from fatty alcohols (C
10C
18) and fatty acids (C
10C
18).
Surface active properties of their aqueous solutions were examined on surface tension, foaming power, foam stability and CMC at 50°C.
In comparison with sodium alkylsulfates (R
iOSO
3Na), the propane sultone derivatives exhibited lower Krafft point and cloud point, excellent surface tension and foaming power even at lower concentrations. The foam stability of these derivatives was similar to each other, but that of fatty acid derivatives was slightly inferior to the others.
The CMC values of the propane sultone derivatives were lower than those of sodium alkylsulfates, and relationship between the CMC and the number (
N) of carbon atoms in the alkyl chain (R
i) was expressed as follows.
R
iOC
3H
6SO
3Na ; log CMC =1.15 - 0.292
NR
iCOOC
3H
6SO
3Na ; log CMC = 0.99 - 0.296
NR
iOSO
3Na ; log CMC =1.39 - 0.292
NFurthermore, the relationship between the log CMC and the length of surface active ion (
L, Å) could be represented as the following equations.
R
iOC
3H
6SO
3- ; log CMC = 3.09 - 0.233
LR
iCOOC
3H
6SO
3- ; log CMC = 3.17 - 0.233
LR
iOSO
3-; log CMC = 2.37 = 0.231
LFrom these equations it is suggested that the hydrophilic groups of -O- and -COO- decrease the lipophilic property of the hydrocarbon chain by 1.4 and 0.7 units of -CH
2- respectively in regard to the CMC value.
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