Octadecyltrimethylammonium bromid

Direct measurement of adsorptive stripping voltaimnetric peaks using HMDE 0.60 V and accumulation potential of -0.40V Dilution in phosphate buffer and water, analyzed in Vis region Ion pair formation with octadecyltrimethylammonium bromide at pH 5.6, extraction of ion pair into n-butanol Sample solution mixed with 1 M HCl, ethanol and purification on Sephadex DEAE 25 gel, gel beads are filtered off, packed into 1 nun cell and absorbance measured... 

Phenylene-bridged periodic mesoporous organosilicas, with both amorphous and crystal-like walls, (referred to in the following as AW-Ph-HMM and CW-Ph-HMM, respectively) were synthesized and characterized as previously reported [6,7]. BTEB was used as a precursor for both solids the surfactant was Brij-76 (Ci8H37(OCH2CH2)nOH) in acidic media for AW-Ph-HMM and octadecyl-trimethylammonium bromide(ODTMA) in basic media for CW-Ph-HMM. A purely siliceous MCM-41 sample was also synthesised, the first step being the solution of octadecyltrimethylammonium bromide in a basic aqueous solution (NH3), kept a 333 K. Tetraethyl orthosilicate (TEOS) was then added in all cases dropwise, and the mixture stirred for 24h at room temperature (H20 34.2 g/ NH3 (15%) 8.52 g/ ODTMA 0.73 g TEOS 3.24 g). After further 24 hours in hydrothermal conditions at 368 K, the sample... 

Actual transfer distance along the primary DNA ds Interduplex center-to-center separation Spermine tetrahydrochloride Dodecyltrimethylammonium bromide Octadecyltrimethylammonium bromide Poly-L-lysine hydrobromide Polyethylenimine hydrochloride Ionization energy... 

Octadecyltrimethylammonium bromide [1120-02-1] M 392.5. Recrystd from EtOH. Dried in a... 

Three novel mesostructured tungsten sulfides, designated as MTS-W, MTS-M and MTS-C, were prepared by the condensation reaction of (NH4)2WS4 in the presence of octadecyltrimethylammonium bromide (OTAB) under refluxing conditions in water, methanol and carbon tetrachloride at 373 K, 338 K and 350 K, respectively. The three as-synthesized metal sulfides all have a layered structure with the d-spacing of 31 A, 30 A or 37 A. Partial removal of the organic surfactants from the layer galleries can be achieved by solvent extraction. 

Ammonium tetrathiotungstate, octadecyltrimethylammonium bromide, anhydrous methanol and carbon tetrachloride were purchased from Aldrich Chemical, Co. and used without further purification. 

Figure 7. Surface pressure-area isotherms for an equimolar mixture of sodium octadecyl sulfate and octadecyltrimethylammonium bromide at the n-heptane-O.OOlM sodium chloride interface. ...

The best results in terms of activity have been obtained with cationic surfactants such as octadecyltrimethylammonium bromide. The normal to branched (njiso) aldehydes ratio was found to be very dependent on the nature of the surfactant. For example, methyl 9-decenoate hydroformylation gave methyl 11-formylunde-canoate with an n/iso aldehydes ratio of 6.1 1, 4.0 1, 2.3 1 and with anionic, amphophilic, and cationic surfactants, respectively. Interestingly, hydroformylation of this substrate has also been achieved successfully with inverse-phase transfer catalysts such as chemically modified /l-cyclodcxtrins. In this approach, the cyclodextrin forms an inclusion complex with methyl 9-decenoate and transfers the alkene into the aqueous phase. Under optimal conditions, the aldehydes are obtained in a 100% yield and in an n/iso aldehydes ratio of 2.3 1 [10]. 

Figure 12 indicates the phase behavior of cationic systems as a function of two formulation variables, for both quaternary (tetra-, hexa-, and octadecyltrimethylammonium bromides) and amine salts at pH 3. 

It may be mentioned here that two stage (or double) percolation has been reported by Ray and Moulik [92] and Maiti et al. [93] for (water/AOT/decanol) and water/DTAB (octadecyltrimethylammonium bromide)-butanol/heptane microemulsion systems, respectively. The double percolation process for AOT/ decane/NaCl (0.5%) was also reported by Eicke et al. by conductivity, viscosity, and electro-optical Kerr effect [94]. The two processes demarcated three structural regimes viz, o/w, w/o, and oil or water continuous. 

K. Maiti, D. Mitra, A.K. Panda, S.C. Bhattacharya, and S.P. Moulik 2007 Physicochemical studies of octadecyltrimethylammonium bromide A critical assessment of its solution behavior with reference to formation of micelles and microemulsion with n-butanol and -heptane, J. Phys. Chem. B 111, 14175-14185. 

The present paper reports the results of investigation of raw MCM-41 silica under high pressure. The main aim of these studies was more detailed description of structural changes in organic template. The PALS experiments were performed for MCM-41 prepared with octadecyltrimethylammonium bromide as a template. To the best of our knowledge, there are no data on the effect of compression under inert gas on properties and structural changes of MCM-41 with the organic template present in the pores of as-synthesized sample. 

Mesoporous silica MCM-41 was prepared following the synthesis procedure reported previously [8]. MCM-41 material was synthesized, using tetraethyl orthosilicate (TEOS) as a silica source, octadecyltrimethylammonium bromide (C18TMAB) as a template and ammonia as the catalyst. The precipitated surfactant-silica mesophase was filtered, washed with distilled water and dried at 323K. Part of as-synthesized samples was next calcined at 823K in air atmosphere and additionally thermally treated in oxygen to remove the carbon deposits located inside the channels. 

Y. Xi, W. Martens, H. He, and R. L. Frost. Thermogravimetric analysis of organoclays intercalated with the surfactant octadecyltrimethylammonium bromide. Journal of Thermal Analysis and Calorimetry, 81 (2005), 91-97. 

Octadecyl sulfate, sodium salt. See Sodium stearyl sulfate N-Octadecyl-N-(sulfosuccinyl) aspartic acid, tetrasodium salt. SeeTetrasodium dicarboxyethyl stearyl sulfosuccinamate Octadecyl trimethyl ammonium bromide Octadecyltrimethylammonium bromide. See Steartrimonium bromide Octadecyl trimethyl ammonium chloride. See Steartrimonium chloride 2,2,3,3,5,5,6,6-Octafluoro-4-(trifluoromethyl)morpholine. See Perfluoro-N-meth-ylmorpholine... 

Synonyms Octadecyl trimethyl ammonium bromide Octadecyltrimethylammonium bromide Stearyl trimethyl ammoium bromide Empirical BrC2,H4gN... 

MTAB) (c) Cetyltrimethylammonium bromide (CTAB) (d) octadecyltrimethylammonium bromide (OTAB). Reproduced with permission from Ref [73] 2004 Institute of Physics. 

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