Methylsuccinic Acid Data

The tables of data for the pure aqueous acid are given below.

(1) Osmotic Coefficients from Bulk Solution Measurements

     m        osm        t     uncert.   ref.     weight
  0.300      0.9762     25.0   0.055(a)   a        1.0  
  0.400      0.9555     25.0   0.041(a)   a        1.0  
  0.500      0.9339     25.0   0.033(a)   a        1.0  
  0.564      0.9116     25.0   0.029(a)   a        1.0  
  0.568      0.9068     25.0   0.029(a)   a        1.0  
  0.600      0.9119     25.0   0.028(a)   a        1.0  
  0.700      0.9065     25.0   0.024(a)   a        1.0  
  0.800      0.9144     25.0   0.021(a)   a        1.0  
  0.900      0.9155     25.0   0.018(a)   a        1.0  
  1.000      0.9189     25.0   0.017(a)   a        1.0  
  4.184      0.6109     25.0   0.042(b)   b        1.0

Notes and References

Symbols: m - molality; osm - molal osmotic coefficient; t - experimental temperature (^oC); uncert. - probable uncertainty in the data (see note futher below); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
In addition to the data listed above Clegg and Seinfeld (2006a) fitted water activities generated using UNIFAC, with parameters as given in Table 3 of Peng et al. (C. Peng, M. N. Chan and C. K. Chan (2001) Environ. Sci. Technol. 35, 4495-4501). For program verification, we list here some of the UNIFAC-calculated molal osmotic coefficients for acid molalities from 1.0 to 50.0 mol kg^-1: (1.00, 0.8813889), (10.0, 0.6751579), (20.0, 0.7375490), (50.0, 0.7733660).
Sources: a - M. Davies and D. K. Thomas (1956) J. Phys. Chem. 60, 41-44; b - C. Marcolli, B. P. Luo and Th. Peter (2004) J. Phys. Chem. A 108, 2216-2224.
Uncertainties: (a) in the listed osmotic coefficient osm, based upon ±0.007 mmHg in the measured pressure difference; (b) in the listed osmotic coefficient osm, based upon ±0.003 in the measured water activity aW.