Stearyltrimethylammonium chloride

In addition to electrostatic stabilization, steric stabilization was found to be an important factor in the microemulsion polymerization of MMA. A comparative stability study was performed on MMA polymerization in tetradecylammonium bromide (TTAB) or stearyltrimethylammonium chloride (STAC) microemulsions [128]. A strong increase in particle size was observed above 50% conversion for the former system, whereas the size remained rather constant up to 98% conversion for the latter. Similarly, ftp increased from 1.75 to 35.6 when the conversion went from 61% to 93% for TTAB systems but remained around 1.4 for STAC systems. These results give clear evidence of the occurrence of particle... 

Stearyltrimethylammonium chloride Phenol chloroformates from phenols 204. GHg... 

Liq. phosgene added in one portion at 0° to 2,2-bis-(p-hydroxyphenyl)propane in chlorobenzene containing stearyltrimethylammonium chloride, the cooling bath removed, warmed cautiously, finally heated 1.25 hrs. at 126°, and the product isolated after a total of 3 hrs. -> 2,2-bis-(p-hydroxyphenyl)propane di(chloroformate). Y 94%. F. e. and catalysts, also limitation, s. R. J. Gotter, M. Matzner, and R. P. Kurkjy, Ghem. Ind. 1965, 791. 

FIG. 6 Structure of the ion pair of stearyltrimethylammonium chloride and sodium iV-lauroyl-Rmethyl-P-alanine mixture. 

Figure 12 Phase diagram of soditim-JV-laiiroyl-JV-methyl-p-alanine—stearyltrimethylammonium chloride.

As shown in Table 3.1.2, some authors have proposed adding different reagents to the mobile phase to reduce the peak tailing of some componnds, like for example acetic acid (AcOH) in the event of BZ3 (DiNunzio and Gadde, 1990), or ethylenediaminetetraacetic acid (EDTA) for BDM determination (Schakel et al, 2004). Salts, snch as citrate, phosphate and ammonium or sodium acetates, have often been nsed for bnffering purposes. On the other hand, different authors have proposed the use of voluminous ions like tetram-ethylammonium chloride (TMAC) and/or sodinm perchlorate (Gagliardi et al, 1986, 1987, 1989 De Orsi et al, 1995), or stearyltrimethylammonium chloride (STAC) (Ohba et al, 1991) to establish an ion-pair partition process. Moreover, the nse of cyclodextrines has helped to solve unresolved peaks, as performed by Chisvert et al (2001d) who employed hydroxypropyl-jS-cyclodextrine (HP-j -CD) as mobile-phase modifier. 

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