Jump to main content
Jump to site search

Issue 31, 2016
Previous Article Next Article

Microphase separation upon crystallization of small amphiphilic molecules: ‘low’ temperature form II of sodium benzoate (E 211)

Author affiliations

Abstract

A so far unknown low temperature polymorph (form II crystallized at 350 °C) of the common food preservative sodium benzoate (NaBz; E 211) could be crystallized by annealing (7 days) of the poorly crystalline technical material. Its crystal structure was solved by indexing a tiny single crystal by electron diffraction followed by structure solution and refinement applying powder X-ray diffraction (PXRD). The new polymorph shows many structural similarities to form I (crystallized at 420 °C). Both form I and II are the result of a microphase separation: the structures consist of pseudo-hexagonal packings of rod-shaped micelles where the core consists of sodium cations being coordinated by the carboxylic groups, while the phenyl moieties of benzoate point outwards rendering the micelle surface hydrophobic. The structures differ by the degree of elliptical distortion of the rods which is more pronounced for the new form II due to incorporation of an additional Na-benzoate moiety into the circumference of the rods.

Graphical abstract: Microphase separation upon crystallization of small amphiphilic molecules: ‘low’ temperature form II of sodium benzoate (E 211)

Back to tab navigation

Supplementary files

Publication details

The article was received on 03 Jun 2016, accepted on 21 Jun 2016 and first published on 22 Jun 2016


Article type: Paper
DOI: 10.1039/C6CE01281G
CrystEngComm, 2016,18, 5811-5817

  •   Request permissions

    Microphase separation upon crystallization of small amphiphilic molecules: ‘low’ temperature form II of sodium benzoate (E 211)

    T. W. Martin, T. E. Gorelik, D. Greim, C. Butterhof, U. Kolb, J. Senker and J. Breu, CrystEngComm, 2016, 18, 5811
    DOI: 10.1039/C6CE01281G

Search articles by author

Spotlight

Advertisements