Cetrimonium bromide

Cetrimonium bromide
Names
Preferred IUPAC name
N,N,N-Trimethylhexadecan-1-aminium bromide
Other names
  • Cetyltrimethylammonium bromide
  • CTAB
  • Hexadecyltrimethylammonium bromide
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.283 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C19H42N.BrH/c1-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20(2,3)4;/h5-19H2,1-4H3;1H/q+1;/p-1 checkY
    Key: LZZYPRNAOMGNLH-UHFFFAOYSA-M checkY
  • InChI=1/C19H42N.BrH/c1-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20(2,3)4;/h5-19H2,1-4H3;1H/q+1;/p-1
    Key: LZZYPRNAOMGNLH-REWHXWOFAU
  • CCCCCCCCCCCCCCCC[N+](C)(C)C.[Br-]
Properties
C19H42BrN
Molar mass 364.45 g/mol
Appearance white powder
Melting point 237 to 243 °C (459 to 469 °F; 510 to 516 K) (decomposes)
Pharmacology
D08AJ02 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Cetrimonium bromide, also known with the abbreviation CTAB, is a quaternary ammonium surfactant with a condensed structural formula [(C16H33)N(CH3)3]Br.

It is one of the components of the topical antiseptic cetrimide.[1] The cetrimonium (hexadecyltrimethylammonium) cation is an effective antiseptic agent against bacteria and fungi. It is also one of the main components of some buffers for the extraction of DNA.[2] It has been widely used in synthesis of gold nanoparticles (e.g., spheres, rods, bipyramids), mesoporous silica nanoparticles (e.g., MCM-41), and hair conditioning products. The closely related compounds cetrimonium chloride and cetrimonium stearate are also used as topical antiseptics and may be found in many household products such as shampoos and cosmetics. CTAB, due to its relatively high cost, is typically only used in select cosmetics.

As with most surfactants, CTAB forms micelles in aqueous solutions. At 303 K (30 °C) it forms micelles with aggregation number 75–120 (depending on method of determination; average ~95) and degree of ionization, α = 0.2–0.1 (fractional charge; from low to high concentration).[3] The binding constant (K°) of Br− counterion to a CTA+ micelle at 303 K (30 °C) is c. 400 M-1. This value is calculated from Br− and CTA+ ion selective electrode measurements and conductometry data by using literature data for micelle size (r = ~3 nm)[citation needed], extrapolated to the critical micelle concentration of 1 mM[citation needed]. However, K° varies with total surfactant concentration so it is extrapolated to the point at which micelle concentration is zero.[citation needed]

  1. ^ Laemmli, U. K. (1970-08-15). "Cleavage of structural proteins during the assembly of the head of bacteriophage T4". Nature. 227 (5259): 680–685. Bibcode:1970Natur.227..680L. doi:10.1038/227680a0. ISSN 0028-0836. PMID 5432063. S2CID 3105149.
  2. ^ Clarke, Joseph D. (2009-03-01). "Cetyltrimethyl Ammonium Bromide (CTAB) DNA Miniprep for Plant DNA Isolation". Cold Spring Harbor Protocols. 2009 (3): pdb.prot5177. doi:10.1101/pdb.prot5177. ISSN 1940-3402. PMID 20147112.
  3. ^ Bunton, Clifford A.; Nome, Faruk; Quina, Frank H.; Romsted, Laurence S. (1991-12-01). "Ion binding and reactivity at charged aqueous interfaces". Accounts of Chemical Research. 24 (12): 357–364. doi:10.1021/ar00012a001. ISSN 0001-4842.