I'm trying to dissolve sodium alginate in a co-solvent of formic acid: acetic acid, but until now I can not get it. Do yoy know if is this possible ? Because what I find in the literature is thant sodium alginate is not soluble in organic acids but in some papers they work with any issue of solubility.
The pKa of alginic acid is 1.5-3.5. Using formic acid it will lower the pH and will not be in the deprotonated state that favors solubility. For an acid to be fully deprotonated, the pH should be 2 units above the pKa. Adjust pH acordingly.
Sodium alginate is a inorganic salt will be soluble in mineral acid and not in organic acids.One can try to make soluble in organic solvent adding phase transfer catalyst like Benzo-18-crown -6 crown ether or tetra-alkyl ammonium bromide.
Dear Karla,
thank for posting this interesting question on RG. Personally I never worked with sodium alginate because we are inorganic chemists. However, I just came across a very interesting PhD thesis edealing with the solubility of sodium alginate in organic media. I hope this will help you in your analysis:
Chemical Modification of Alginates in Organic Media
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.868.5823&rep=rep1&type=pdf
(please see the attached pdf file)
Good luck with your research!
- [Alginic acid is a linear copolymer with homopolymeric blocks of (1→4)-linked β-D-mannuronate (M) and α-L-guluronate (G) residues, respectively, covalently linked together in different sequences or blocks.]
- To dissolve Alginate, try using (CH3)4N, AcO salt with a Cation exchange like Chellex (batch procedure). Raw Alginic acid may come with different divalent cations that crosslink some polymers (make snot). Me4N,OH (Aldrich) is very soluble in a number of organic solvents. Anionic Chellex-NMe4 shall retain Ca(II), Zn(II), Mg(II) and a variety of Bugers(II).
- Look out the reference bellow:
- AU Clemente Bretti, Francesco Crea, Claudia Foti and Clemente Bretti, and Silvio Sammartano
JN J. Chem. Eng. Data 2006, 51, 5, 1660–1667
Publication Date:August 4, 2006
https://doi.org/10.1021/je060132t
You know me and my experience with Clifford A. Bunton
Hola Karla, mira lo siguiente:
TI Structures, properties and application of alginic acid: A review
- June 2020
- JN International Journal of Biological Macromolecules 162(6)
- DOI: 10.1016/j.ijbiomac.2020.06.180
- Qiang Peng's Lab
- AB Alginic acid is a natural polysaccharide, which has been widely concerned and applied due to its excellent water solubility, film formation, biodegradability and biocompatibility. This paper briefly describes the source, properties, structure and application of sodium alginate by summarizing and analyzing the current literature. This paper reviews the application of sodium alginate in the fields of food industry, catalyst, health, water treatment, packaging, immobilized cells, and looks forward to its application prospects.
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