Polymorphism and thermal behavior of sodium cyclamate

  • D. A. V. Medina
  • A. P. G. Ferreira
  • E. T. G. CavalheiroEmail author


Due to its potential thermal degradation or polymorphic transformation, thermal stability of a food additive may limit its use in food preparations, when heating process is involved. In this paper, we present an investigation on thermal behavior of sodium cyclamate, one of the most frequently used components in tabletop sweeteners. Thermogravimetric data revealed that sodium cyclamate exists in two polymorphic forms: sodium cyclamate di-hydrated (C6H12NSO3Na·2H2O) and anhydrous sodium cyclamate (C6H12NSO3Na). X-ray powder diffraction data revealed that hydrate and anhydrate sodium cyclamate are true polymorphs. Under heating conditions, the hydrated form dehydrated in a complex multiple-step process. Finally, thermal decomposition of sodium cyclamate was studied and a degradation mechanism is proposed. At 170 °C, sodium cyclamate sublimates and dimerizes, by condensation of two cyclamate moieties, leading to formation of highly pure N,N-diciclohexyl sulfamide, a potential anxiolytic compound.


Cyclamate Phase change Polymorphism Thermal decomposition Dimerization 



Funding was provided by Fundação de Amparo à Pesquisa do Estado de São Paulo (Grant No. 2015/09299-7) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

Supplementary material

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Supplementary material 1 (DOCX 366 kb)


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.Instituto de Química de São CarlosUniversidade de São PauloSão CarlosBrazil

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