51 81 term [ K1lKe/[ H + ] + Klz] [ GI may be considered small and neglected. Since three values of K11 are available from part E, three equations may be formed in three unknowns; [k,!. Kl,K.], [knKln], and K.. Solving these equations it IS found that K. = 0.09, ktzKlt = 0.3285 and the term k1lKl1. K. is very nearly zero (ca. 0.0001). Therefore either kll or K11 is negligible. The fact that the rate is independent of [ H + ] at higher glycol concentration indicates that Kll is negligible and no appreciable Ce(OH)XaG is formed. Since very little Ce(0H)XsG is formed, it is assumed that the di-and triglycolated species of the hydroxylated cerium can also be neglected. Under these assumptions, equationThese values, when used to calculate values of k' are found to fit the experimental data only at the lower glycol concentration. Evaluation of equilibrium constants for the di-and triglycolated species is accomplished by trial and error. I t was found unnecessary to include the cubed power of glycol to fit experimental data. Selecting two higher values of k' at higher glycol concentrations and using the equationit was found that KB = 2.3 and km = 0.0117 sec.-l. In view of the uncertainties encountered in the experimental determination of pseudo rate constants, the values of rate constants and eauilibrium constants are assigned the limits (21) which is of the same form as equation (4) except for the modified subscripts and addition of the hydrogen dependency term. Aaain a t low alvcol concentrations (IG1 = 0.05). the diglycolated cornpiex concentrations may' be considered negligible. Using the value of k' from Part A, and the values of K,, k12K12, and [ H + ] , K12 = 15 and k,e = 0.0225 set.-'. kzz = AMES, IOWATABLE I1 0.09 4= 0.02 15 f 1 2 . 3 3t 0 . 4 0.0225 f 0.0010 see.-' 0.0117 i 0.0020 sec.-l RECEIVED MAY 21, 1951 [CONTRIBUTION NO. 520 FROM THE CHEMICAL LABORATORIES,
It has been previously established' that normally prepared nylon G6 polymers obey I, = 225( [71)1.34
( 2 )The polymers used to derive eq. (2) may not, because of the methods of preparation, be completely equilibrated in all cases; however, very extensive interchange will have taken place during preparation.The close agreement of eq.(1) and (2) demonstrates that nylon 66 polymers of two series, one prepared by polycondensation and the other by random hydrolytic scission of a high molecular weight polymer, have the same ratio of viscosity-to-number-average degrees of polymerization. Although the ratio of two different molecular weight averages characterizes but does not define a distribution function, it is certain that nylons prepared in both the presence and absence of chain interchange reactions have a common distribution function. Taking into account theoretical and experimental s t u d i e~~~'~.~~ it is equally certain that this distribution function is that described by Flory as the most probable.
eq. (2).I am indebted to British Nylon Spinners Limited for permission to publish this note.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.