Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1985 Kinetic analysis of the dimerization and disproportionation of aqueous glyoxal Alfred Richard Fratzke Jr. Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Chemical Engineering Commons Recommended Citation Fratzke, Alfred Richard Jr., "Kinetic analysis of the dimerization and disproportionation of aqueous glyoxal" (1985). Retrospective Theses and Dissertations. 7845. https://lib.dr.iastate.edu/rtd/7845 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This reproduction was made from a copy of a document sent to us for microfilming. While the most advanced technology has been used to photograph and reproduce this document, the quality of the reproduction is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help clarify markings or notations which may appear on this reproduction. 1.The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure complete continuity. 2. When an image on the film is obliterated with a round black mark, it is an indication of either blurred copy because of movement during exposure, duplicate copy, or copyrighted materials that should not have been filmed. For blurred pages, a good image of the page can be found in the adjacent frame. If copyrighted materials were deleted, a target note will appear listing the pages in the adjacent frame. 3. When a map, drawing or chart, etc., is part of the material being photographed, a definite method of "sectioning" the material has been followed. It is customary to begin filming at the upper left hand comer of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete. 4. For illustrations that cannot be satisfactorily reproduced by xerographic means, photographic prints can be purchased at additional cost and inserted into your xerographic copy. These prints are available upon request from the Dissertations Customer Services Department. 5. Some pages in any document may have indistinct print. In all cases the best available copy has been filmed. Universi^ Micrcxilms Intemationcil 300 N. Zeeb Road Ann Arbor, Ml 48106 8514397 Fratzke, Alfred Richard, Jr. KINETIC ANALYSIS OF THE DIMERIZATION AND DISPROPORTIONATION OF AQUEOUS GLYOXAL Iowa State University PH.D. 1985 University Microfilms IntsrnBtionsi 300 N. Zeeb Road, Ann Arbor, Ml48106 Copyright 1985 by Fratzke, Alfred Richard, Jr. All Rights Reserved PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V 1. Glossy photographs or pages \/ 2. Colored illustrations, paper or print 3. Photographs with dark background 4. Illustrations are poor copy 5. Pages with black marks, not original copy 6. Print shows through as there is text on both sides of page. 7. Indistinct, broken or small print on several pages 8. Print exceeds margin requirements 9. Tightly bound copy with print lost in spine 10. Computer printout pages with indistinct print _ 11. Page(s) lacking when material received, and not available from school or author. 12. Page(s) seem to be missing in numbering only eis text follows. 13. Two pages numbered . Text follows. 14. Curiing and wrinkled pages 15. Dissertation contains pages with print at a slant, filmed as received 16. Other University Microfilms International Kinetic analysis of the dimerization and dxsproportionation of aqueous glyoxal by Alfred Richard Fratzke, Jr  Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Major: Chemical Engineering Approved: Signature was redacted for privacy. Iowa State University Ames, Iowa 1985 Copyright©Âlfred Richard Fratzke, Jr., 1985- All rights reserved. ii TABLE OF CONTENTS Page 1. INTRODUCTION 1 1.1. Objactives 1 1.2. Project History 2 2. RELATED LITERATURE 5 2.1. Carbonyl Hydrations 8 2.2. Related Dimerization and Mutarotation Studies 22 2.3. Related Dxsproportiasmaticn Studies 35 3. KINETIC ANALYSIS OF THE DISPROPORTIONATIOM OF AQUEOUS GLYOXAL 44 3.1. Experimental Methods Materials 44 3.1.1. Analysis for glyoxal 44 3.1.2. Experimental design — pseudo—first—order stmâies 46 3.1.3. Treatment of kinetic data 53 3.1.4. Experimental design — integral rate stmdi.es 58 3.1.5. Materials 60 3.2. Results — Disproportionation Kimetîcs 61 3.2.1. DeterminatiouL of overall rate expression 61 3.2.2. Effect of temperature on rate coefficients a^ and a^ 68 3.2.3. Effect of ioraic strength on rate coefficients and 73 3.2.4. Rate determinations in bicarbonate/carbonate buffer 80 3.2.5. Disproportionation at intermediate glyoxal concentrations 85 3.3. Interpretation of Kinetic Results 99 3.3.1. Empirical comparisons with related carbonyl compounds 100 3.3.2. Correlation with previous kinetic stmdies 107 3.3.3. Kinetic model of the disproportionation of glyoxal 109 3.3.4. Implications of the kinetic model 122 3.3.5. Extension of the kinetic model to higher snabstrate concentrations and alkalimities 127 3.3.6. Glyoxal as an intermediate in the oxidatlou of glycolaldehyde 133 iii 4. THERMODYNAMIC AND KHiETIC ANALYSIS OF THE DIMERIZAIION OF AQUEOUS GLYOXAL 140 4.1. Experimental Methods and Materials 140 4.1.1. Chromatographic separation of dimerle and monomeric glyoxal 141 4.1.2. Experimental design 153 4.1.3. Determination of buffer pH 136 4.1.4. Materials 160 4.2. Results — Dimerization Thermodynamics 161 4.2.1. Quanti tat ion of chromatographic results 161 4.2.2. Determination of 165 Dapp 4.2.3. Effect of temperature on 173 4.2.4. Effects of ionic strength and pH on 182 4.2.5. Higher—order oligomers 188 4.3. Results — Dimerization Kinetics 193 4.3.1. Mathematical analysis of kinetic results 194 4.3.2. Reaction order with respect to monomeric and dimerîc glyoxal 199 4.3.3. Effect of buffer salts on 209 4.3.4. Effect of pH (pOH) on ^^3 4.3.5. Effect of temperature on 219 4.4. Interpretation of Kinetic Results 226 4.4.1. Empirical comparison with related carbonyls 226 4.4.2. Kinetic models for the dimerization of glyoxal 233 5. CONCLUSIONS 253 5.1. Summary of Results 253 5.1.1. Analytical findings 253 5.1.2. Empirical findings 255 5.1.3. Theoretical findings 258 5.2. Directions for Future Research 261 5.2.1. Further dïsproportionation studies with glyoxal 261 5.2.2. Further dimerization studies with glyoxal 268 iv 6. REFERENCES 271 7. APPENDIX 277 7.1. Sampling Error in a "Cup—mixed" Sampled First—order System 277 7.2. Reaction Order with Respect to Hydroxide Ion Concentration 281 7.3. Kinetic Model of the Disproportionation of Formaldelnyde 287 7.4. Preparation of Phthalate Buffers of Constant Ionic Strength 291 7.5. Implications of the Steady—State Dimerizatimm Model for Saccharide Mutarotaltions 296 1 1. INTRODUCTION 1.1. Objectives The principal objective of this research has been, simply, to contrib­ ute significantly to our scientific understanding of carbohydrate reactions in aqueous solution. A secondary objective has been to build an experi­ mental and theoretical framework for use in the study of related but more complex reactions. Although the focus of my research has narrowed consid­ erably during the course of my studies, culminating in the study of glyoxal presented herein, the above objectives have remained unchanged. The two—carbon dicarbonyl glyoxal, CHOCHO, is in many respects a remarkable compound. In common with other a-dicarbonyls, a-hydroxyalde­ hydes , and even formaldehyde, glyoxal readily undergoes reversible polym­ erization in both acidic and basic solution. At a slower rate, glyoxal in alkaline solution undergoes an intramolecular dlsproportionation character­ istic of a—dicarbonyls. However, because of its simple, symmetrical struc­ ture, lacking an a-hydroxy moiety or even an enolizable hydrogen, glyoxal polymerizes and disproportionates free of the complications of enolization, such as aldolization, isomerization, and oxidation. More remarkable, perhaps, is the fact that despite its simple two-carbon structure, commer­ cial availability, and known reactvity toward a variety of nucleophilic addition compounds, the chemistry of the self—reactions of glyoxal had heretofore escaped serious examination. It is this author's opinion that detailed knowledge of these reactions should be prerequisite to a systematic study of many of the above addition reactions. In Sees. 3 and 4 are reported the results of detailed investigations 2 into the disproportionation and oligomerization, respectively, of glyoxal. In each study the first and overriding goal was to determine as accurately as possible (within constraints of time and support) over a broad range of experimental conditions the equilibrium product distributions and rates of reaction of glyoxal and to express the results in terms of appropriate equilibrium constants and mathematical rate laws. A second objective was to infer possible reaction mechanisms, consistent with the observed rate laws, from which extensions might be made to related reactions. It is hoped that the kinetic and thermodynamic findings reported herein will prove reliable and so be of benefit to those studying more complex reactions involving glyoxal or related compounds.