Trimesic acid is reported to be soluble in water (26,3g/L, Sigma) but I see that most publications use a volume mixture 1:1 water:ethanol. Is it related to the kinetics of the dissolution? Do I need to increase the temperature in order to obtain the solubility reported?
Thanks
The data for trimesic acid at temperatures from 277 to 330 K are available in the attached file. Many other solubilities of benzene polycarboxylic acids in water are also listed.
thank you professor! I red the publication (as well as the one from Zhang(2016)); solubility there is about 2,1g/L at 25°C (although I am not sure because solubility is reported in molar fraction and the mass of water it is not specified, I suppose 1kg). The value is far from what is reported on the Sigma website. Are you using this compound in your lab?
The reported solubility in J. Chem. Thermodynamics 38 (2006) 565–571 is rather molality (moles in 1 kg of solvent) which is close to molarity for dilute solutions in water at 298 K. If I use 0.01077 at 298.15 K, and M=210.14 g/mol, I get 2.26 g/kg of water. The Zhang paper (2016) uses mole fraction ("molar fraction of
the solubility x3"; should be in fact "solubility x3 is given in units of mole fraction"), so at 301.05 K, close to 298 K, the solubility is 0.15*10-3 mole per mole of water = 0.0315 g per 18 g of water (or 18 mL of water) = 1.75 g per kg of water = 1.75 g per 1 L. Please recheck all these calculations. I saw that the trimesic acid is 99.5% in the 2016 paper, and only 97% (Fluka) in the 2006 paper.
Thanks again professor for clarifying this, I got the same results; still the value (around 2g/L) is far from what reported by Sigma so, based on what is reported on the publications, I will try dissolving BTC in water at the lab.
In the catalogs, purity from 94 to 98 % is given.
For example Trimesic acid for synthesis (about 95%), Sigma-Aldrich:
Solubility 15 g/l (20 °C)
https://uk.vwr.com/store/product/750426/trimesic-acid-for-synthesis
A part of the problem maybe the purity, if the impurities are soluble in water. Anyway this discrepancy is striking.
After trying dissolving BTC in the lab (in water at 24°C), I can say that the value is closer to the one reported in the publications (1.98g/L) to the one of the supplier (Aldrich). Purity of the BTC I used is 98%.
- Badges
- Science topic
- Similar topics
- Linguistics
- Composition Studies
- Publications