HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by McAuliffe, C. Articles by Coleman, N. T. Search for Related Content PubMed Articles by McAuliffe, C. Articles by Coleman, N. T. Agricola Articles by McAuliffe, C. Articles by Coleman, N. T.

H-ion Catalysis by Acid Clays and Exchange Resins¹

ABSTRACT

Except where complicated by the adsorption or the limited diffusion of the molecular reactant, rates of H-ion catalyzed hydrolysis of ethyl acetate or inversion of sucrose were found to be proportional to the concentration of H-ions in a variety of ion exchange systems. No correlation was found to exist between potentiometric H-ion activities in clay or exchange resin suspensions and their efficiencies as catalysts.

Not all acid clays were effective as H-ion catalysts. On the basis of total acidity, Al-clays had low catalytic activity. In general, for clays and resins partially saturated with metal cations, catalysis by non-neutralized exchangeable H was as efficient as in the case of complete H-saturation.

It is suggested that effective ion concentrations in ion exchange systems are not the same for all reactions. The effective ion concentration approaches the total concentration for reactions between exchangeable ions and neutral molecules which are not limited by the diffusion rate of the molecular reactant. For reactions involving exchangeable ions and particles of opposite charge, the effective ion concentration approaches the concentration of the inter-particle solution. In dispersed systems, potentiometric pH measures neither of these quantities.

¹ Contribution from the Department of Agronomy, North Carolina Agr. Exp. Sta. Published with the approval of the Director as Paper No. 608 of the Journal series. Presented before Div. II, Soil Science Society of America, St. Paul, Minn., Nov. 9, 1954.

² Associate Professors of Agronomy.

Received for publication September 18, 1954.