Prigogine's evolution criterion is illustrated non-linear state nonlinear state in chemical reaction systems. It was proved that how at least in chemical reactions; the entropy production per unit time accords to the control parameters is in fact a Lyapunov function. This is indeed an evolution criterion in the nonlinear region and also the global stability is properly assured. Finally, it was shown that for fixed values of the control parameters, the system corresponding dynamical state exhibits a higher value of the entropy production per unit time, which can be considered in fact, an extension of the non-variational principle of maximum entropy.

Se ilustra el criterio evolutivo de Prigogine para estados de no-equilibrio en sistemas de reacción química. Se muestra como para modelos no-lineales de reacciones químicas, la producción de entropía por unidad de tiempo, en función de los parámetros de control, es de hecho una función de Lyapunov, lo cual constituye un criterio evolutivo en la región no-lineal, y a su vez asegura la estabilidad global. Finalmente, se mostró que para valores fijos de los parámetros de control, el estado dinámico correspondiente del sistema exhibe un valor mayor de producción de entropía por unidad de tiempo, lo cual puede considerarse de hecho una extensión del principio no variacional de máxima entropía.

The polymerization of poly (2- furyl) methylenesulfide -- POLYTHIOFURFURAL -- was performed in an 0.36 mol/L aqueous solution of furfuraldehyde, saturated by bubbling hydrogen sulfide for 2 h at different temperatures. The reaction product was thoroughly washed and dried at 40 °C under vacuum. Poly (2-furyl) methylenesulfyde is a yellow powder with a rather unpleasant odor. The polythiofurfural obtained [ -CH(C4H3O)-S-] is a furan with thiols end groups. These are active adsorption centers for metal ions. The polythiofurfural was soluble in acetone and chloroform and its yields attained 80%. Morphological analysis by Scanning Eletronic Microscopy indicates a regular and dense surface in an interesting spacial arrangement. Preliminary isotherms adsorption studies indicate specific affinity forNi (II) and Co (II) and different capacity adsorption, 0.022 and 0.045 mmol per gram, respectively.