Amphoteric surfactants amine value

The sulfated alkylbenzenesulfonamides (no. 7-8) and alkylaroylsulfo-propionates (no. 9) were found to be efficient lime soap dispersants [27]. Although the nonionics (nos. 10-11) had low LSDR values they did not potentiate the detergency of soap and exhibited some antagonism. Amphoteric surfactants with alkyl side chains from C12 to C18 (nos. 12-13) possessed the lowest LSDR values, ranging from 2 to 4. The amine oxide derived from an aromatic sulfonamide had a low LSDR of 5 close to that of amphoterics. 

These types of surfactants exhibit anionic properties at high pH and cationic properties at low pH and may be categorized as [87] jS-iV-alkylaminopropionic acids, TZ-alkyl-yS-iminodipropionic acids, imidazoline carboxylates, W-alkylbetaines and amine oxides. The sulfobetaines are amphoteric at all values of pH. These surfactants are not commonly used in emulsion polymerization formulations. 

Henrich developed a comprehensive TLC method for identification of surfactants in formulations (4). She specified two reversed-phase and four normal phase systems, with detection by fluorescence quenching, pinacryptol yellow and rhodamine B, and iodine. Prior to visualization, one plate was scanned with a densitometer at 254 nm, and UV reflectance spectra were recorded for each spot detected. Tables were prepared showing the Rf values of 150 standard surfactants in each of the six systems, along with the reflectance spectra and response to the visualizers. This system allows for systematic identification of compounds of a number of surfactant types (LAS, alcohol sulfates and ether sulfates, alkane sulfonates, sufosuccinate esters, phosphate compounds, AE, APE, ethoxylated sorbi-tan esters, mono- and dialkanolamides, EO/PO copolymers, amine oxides, quaternary amines, amphoterics and miscellaneous compounds). Supplementary analysis by normal phase HPLC aided in exactly characterizing ethoxylated compounds. For confirmation, the separated spots may be scraped from one of the silica gel plates and the surfactant extracted from the silica with methanol and identified by IR spectroscopy. 

---