ISSN:
1435-1536
Keywords:
Chondroitin sulfate
;
tetraalkylammonium counterion
;
dilution enthalpy
;
thermodynamic properties
;
polyacrylate
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The dilution enthalpies,Δ dil H, of tetraalkylammonium chondroitin 4-sulfate (R4NChSA) and polyacrylate (R4NPAA) having methyl (Me), ethyl (Et), propyl (Pr) and butyl (Bu) as alkyl groups (R) were measured to elucidate the effects of hydrophobic counterions. TheΔ dil H of R4NChS-A and R4NPAA were negative (exothermic) and decreased as the carbon number of tetraalkylammonium cation (R4N+) increased. These results were found to possess the same effects onΔ dil H as these of bromides. The non-electrostatic terms of dilution enthalpiesΔ dil H n of R4NChS and R4NPAA were evaluated by using the electrostatic terms ofΔ dil H obtained from Manning's theory. TheΔ dil H n of R4NChS-A and R4NPAA decreased, i.e., their exothermic tendencies increased as the carbon number of R4N+ increased, and the rate of decrease of the R4NPAA was more than that of the R4NChS-A. These results are discussed in relation to the increase of the hydrated water structure around R4N+ on dilution.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00654739
