M-Dodecyl bromide

The above method for preparing M-dodecyl bromide is an adaptation of that of Ruzicka1 and has been published recently.2 It is thought to present some advantages in ease of manipulation and quality of product over the older method involving the action of aqueous hydrobromic acid on the alcohol in the presence of sulfuric acid.3... 

To test this hypothesis, very low density lipoprotein (VLDL, d<1.0 gm/ml), low density lipoprotein (LDL, d=l.02-1.063) and high density lipoprotein (HDL, d=l.09-1.21) were isolated from outdated human plasma by ultracentrifugation according to established procedures (27,28), using potassium bromide for density adjustments and stored at -20° C in the presence of 20% sucrose before use. The purity of individual lipoprotein fractions thus obtained was established by polyacrylamide gel electrophoresis in sodium dodecyl buffer system (2 ) and filtration through a Sepha-rose 6B column, equilibrated with 0.2 M potassium bromide in 0.1 M sodium phosphate buffer, pH 7.2. Protein (30) and cholesterol... 

M-DODECYL MERCAPTAN, 21, 36 S-Dodecylthiuronium bromide, 21, 37 m-Dodecyl >-toluenesulfonate, 20, SO... 

Laurylimidazoline sulfobetaine. See Sodium lauroamphohydroxypropylsulfonate Lauryl isoquinolinium bromide CAS 93-23-2 EINECS/ELINCS 202-230-9 Synonyms Dodecylisoquinolinium bromide 2-Dodecylisoquinolinium bromide Isoquinolinium, 2-dodecyl-, bromide Classihcation Quaternary ammonium compd. Empirical C21H32N Br Properties M.w. 378.40 Toxicology LD50 (oral, rat) 230 mg/kg primary irritant may cause Gl changes TSCA listed Uses Antimicrobial, antistat, surfactant in cosmetics... 

With the wide variety of surfactants available, including ionic (anionic or cationic), nonionic and zwitterionic, many unique separations and applications can be developed. Because organic modifiers do not decrease the equilibria equally for all solutes, they can also change the selectivity of the mobile phase. Moreover, with electrostatic interactions pla)dng a major role in the selectivity, it is important to specify the pH of the mobile phase. For instance, the measured pH of a 0.1 M sodium dodecyl sulfate (SDS) solution is 6.1 and that of 0.5 M cetyltrimethylammonium bromide (CTAB) is 4.2. These pH values can obviously be changed by appropriate buffers, so that some solutes can be present in ionized form. 

Bromide [41387-42-2]. 10-Dodecylacridine orange. AO-10-Dodecyl bromide. BDA C2pH44BrN3 M 514.591 Used as a hydrophobic fluorescent probe. Cryst. (Et0H/Et20). 

FiG.1 Raman spectra for solid -alkyltrimethylammonium bromides [(a) -hexyl, (b) n-octyl, (c) n-decyl, and (d) M-dodecyl] in the skeletal stretching region. 

Kinetics. The reaction of N-dodecyl 3-carbamoyl pyridinium bromide (I) with cyanide ion in the microemulsions was observed by following the 340 nm absorption maximum of the 4-cyano adduct (II). See equation (1). Following the work of Bunton, Romsted and Thamavit in micelles ( ), a 5/1 mole ratio of KCN to NaOH was employed to prevent cyanide hydrolysis. The pH of each reaction mixture was measured on a Coleman 38A Extended Range pH meter to insure that the system was sufficiently basic to allow essentially complete ionization of the cyanide. The appropriate amounts of cyanide and hydroxide were added to the mlcroemulslon sample within 10 minutes of running a reaction. Cyanide concentration varied between 0.02 and 0.08 M with respect to the water content. Substrate was Injected via a Unimetrics model 1050 syringe directly into a known volume of the yE-nucleophlle mixture in a 1.0 cm UV quartz cell. Absorbance at 340 nm was followed as a function of time on a Perkln-Elmer model 320 spectrophotometer at 25.0 + 0.3 C. Since the Initial bulk concentration of substrate was 10 M, cvanide was always present in considerable excess. 

The effects of micelles of cetyltrimethylammonium bromide (CTABr), tetradecyl-trimethylammonium bromide (TTABr) and sodium dodecyl sulfate (SDS) on the rates of alkaline hydrolysis of securinine (223) were studied at a constant [HO ] (0.05 m). An increase in the total concentrations of CTABr, TTABr and SDS from 0.0 to 0.2 M causes a decrease in the observed pseudo-first-order rate constants (kobs) by factors of ca 2.5, 3, and 7, respectively. The observed data are explained in terms of pseudophase and pseudophase ion-exchange (PIE) models of micelles. Cationic micelles of CTABr speed attack of hydroxide ion upon coumarin (224) twofold owing to a concentration effect. ... 

Surfactants such as cetyl trimethyl ammonium bromide (CTAB), Triton X-100 (TX-lOO) and sodium dodecyl sulphate (SDS) are the most commonly used. CTAB forms large micelles [24-26] with aggregation number 61, cmc 9.2 X 10 M, and a positive micellar Stem layer TX-lOO has aggregation number 139 with neutral OH groups on the Stern layer, and SDS forms negative micelles with cmc 8.3 x 10 M and aggregation number 131. The... 

Kondo, Y., Uchiyama, H., Yoshino, N., Nishiyama, K., and Abe, M. (1995). Spontaneous vesicle formation from aqueous-solutions of didodecyldimethylammonium bromide and sodium dodecyl-sulfate mixtures. Langmuir, 11, 2380. ... 

The reaction of Problem 10 was studied at two different temperatures, and, from the temperature dependence of the rate constants, the authors determined AH% and ASJ, the enthalpy and entropy of activation, respectively. The following values of these parameters were obtained in pure water and in 0.01 M sodium dodecyl sulfate (NaLS) and 0.01 M hexadecyl trimethyl ammonium bromide (CTABr) ... 

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