ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The kinetics of formation and dissociation of mono- and dimethylolthiourea were studied as well as the equilibria among the constituents in alkaline and neutral solutions. The polarographic determination of free formaldehyde and the determination of the reacting constituents by paper chromatography were used as analytical methods. A generally valid relation for equilibrium with a polyfunctional compound, to which formaldehyde is added, was derived and used to calculate both the equilibrium constants for the case of thiourea. The equilibrium constants found do not depend on pH. It was found from the temperature dependence of the equilibrium constant that the formation of monomethylolthiourea is an exothermal reaction. The possibility of formation of tri- and tetramethylolthiourea was discussed. Ways of simplifying the complex kinetic scheme were found which are suitable for calculation of the rate constants. The rate constants of formation and dissociation of mono- and dimethylolthiourea are directly proportional to the concentration of hydroxyl ions in the alkaline region and depend only slightly on the concentration of buffer. The reaction of thiourea with formaldehyde was found to be more rapid than the reaction of urea with formaldehyde in this region. By a graphical solution in which the known rate constants were used, the time dependence was found for the concentrations of all the constituents. The polarographic study of the reaction of thiourea with formaldehyde in strongly alkaline media of Chasanov and Lynch was discussed.
Additional Material:
16 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1958.1203012136
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