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Investigations Concerning Some Factors Influencing Rhythmic Crystallization from Aqueous Solution Majel Margaret Macmasters University of Massachusetts Amherst

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Investigations Concerning Some Factors Influencing Rhythmic Crystallization from Aqueous Solution Majel Margaret Macmasters University of Massachusetts Amherst University of Massachusetts Amherst ScholarWorks@UMass Amherst Doctoral Dissertations 1896 - February 2014 1-1-1934 Investigations concerning some factors influencing rhythmic crystallization from aqueous solution Majel Margaret MacMasters University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/dissertations_1 Recommended Citation MacMasters, Majel Margaret, "Investigations concerning some factors influencing rhythmic crystallization from aqueous solution" (1934). Doctoral Dissertations 1896 - February 2014. 900. https://scholarworks.umass.edu/dissertations_1/900 This Open Access Dissertation is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Doctoral Dissertations 1896 - February 2014 by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. SOME FAC-rORS ItlFLU£i\ClKb RHTTflMIC liii :;oij.nioN LD j 3234 IV1267 1934 Ml 67 DATE DUE 200t UNIVERSITY OF MASSACHUSETTS LIBRARY J^HYS iiCI LD 3234 M267 oC lENCE 1934 M167 INVESTIGATIONS CONCERNING SOME FACTORS INFLUENCING RHYTHMIC CRYSTALLIZATION FROM AQUEOUS SOLUTION Majel Margaret MacMasters Presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts State College Amherst, April, 1954 Outline of Thesis. Page I. Introduction 1 II. Review of Literature and Theoretical Dlcusslons , 2 A. The Liesegang Phenomenon , 2 1. Definition 2 2, History « 2 3, Production 3 4. Influence of Various Conditions ^ .4/ * . 5 a. Concentration ............. 5 b. Light 6 c» Temperature , 8 d. Reaction Meditun 9 B. Periodic Precipitation in the Absence of a Gel 14 !• Introduction 14 2, Production • 14 a* By Metathesis of Compotmds in Solution . 14 b. By Reaction between Gases 17 3. Influence of Various Conditions 18 a. Concentration 18 b. Temperature .............. 19 C. Periodic Banding of Single Substances , . , 20 1. Introduction ..•••.•••••••«• 20 2. History 20 Page 3. Production 21 a* Prom Solution 21 b. From the Melt 24 4. Influence of Various Factors 27 a. Concentration 27 b. Temperature , 27 c. Thickness of Film 28 D. Details of Rhythmic Structiires 30 E. Discussion of Theory • 33 1. The Supers aturat ion Theory of Lieaegang Ring Formation 33 2. The Adsorption Theory 38 3. The Coagulation Theory 40 4« The Diffusion-wave Theory 41 5. Other Diffusion Theories 46 6. Membrane Theories 53 7. Theory of Rhythmic Precipitation in the Absence of Colloids 54 a. By Metathesis of React ants in Solution 54 b. By Reactions between Gases 55 8. Theory of Rhythmic Crystallization .... 56 P, Periodic Structures in Nature 61 III. Purpose of this Work 68 Page IV. Experimental Work 70 A* Apparatus . 70 B. Methods and Results 72 1. Preparation and Cleaning of Slides .... 72 2. Investigations on the Effects of Temperature and Concentration on Rhythmic Crystallization from Solution • . .73 a. Method 73 b. Effects on Rhythmic Crystallization of Cadmium Sulfate 73 c. Effects on Rhythmic Crystallization of Potassitun Bichromate 82 3. Effect of Type of Interface on Rhythmic Crystallization of Potassium Bichromate • .101 4. Rhythmic Crystallization of Cadmium Iodide 103 5. Investigations on the Effects of Specific Impurities on Rhythmic Crystallization . 105 a. Introduction 105 b. Method 106 c. Effect of Potassium Chloride on Rhythmic Crystallization of PotassiTam Bichromate 107 d. Effect of Sodium Chloride on Rhythmic Crystallization of Potassium Bichromate Ill Page e. Effect of Potassium Nitrate on Rhythmic Crystallization of Potassium Dlchrornate 117 f. Effect of Potassltim Sulfate on Rhythmic Cryatallizatlon of Potassixim Bichromate 121 g. Effect of Calcium Chloride on Rhythmic Crystallization of Potassium Bichromate 127 h. Effect of Ferric Chloride on Rhythmic Crystallization of Potassium Bichromate . 132 6, Spacing of Periods from the Center of Crystallization 133 C» Biscusslon of Results • 140 V. Sximmary 155 VI. Bibliography 158 VII. Acknowledgments . 176 I. IHTRODUCTION. In 1896 Llesegang began publication of his ox- tended researches on rhythmic precipitation in the presence of a gel. Today scarcely any scientist Ignores the Importance of further study of the Llesegang phenomenon. The studies already carried out have pointed to probable explanations of many varied phenomena. Such studies, furthermore, have indicated means of practical application in numerous fields. More recent work has shown that the presence of a colloid is not essential for rhythmic pre- cipitation or crystallization. There is still strong feeling, however, that specific impurities must be present, or that optimtim conditions of concentration and temperature must be maintained, for rhythmic crystallization to ensue. The data leading to these beliefs are fragmentary and not entirely convincing. The present investigation was undertaken in an attempt to answer some of the questions which investigators in the field of rhythmic crystallization are now asking. II: REVIEW OP LITERATURE AND THEORETICAL DISCUSSIONS A. The Llesegang Phenomenon . 1. Definition . The Llesegang phenomenon may be defined, broadly, as banded structures resulting from precipitation In a colloidal medium. The bands of sliver chromate produced by metathesis of sliver nitrate and potassium chromate In a gel are characteristic of the phenomenon, and are often used as a type example. Because of the regularity with which the bands are spaced, such precipitation is often called periodic crystallization, rhythmic crystallization, or rhythmic banding. These terms do not necessarily Imply any time periodicity, as does the term periodic reaction, which Is reserved for phenomena in which the velocity of a chemical reaction varies periodically with time. 2. History . The first detailed study of rhythmic precipita- tion was reported by H.E. Llesegang (1,2) in 1896. Rhythmic precipitation had, however, already been reported by other investigators. Bradford (3) claims priority for Lupton (4) whose work was published in 1892} while Hepburn (5) quotes from The Influence of Colloids upon Crystalline Form and Cohesion, published by Ord in London, 1879,(6), to show that this author had, in 1869, obtained and recognized stratified precipitates of calcium oxalate. As early as 1855, however, Runge (7) discussed the reaction of aqueous solutions of metallic salts in sheets of porous paper, emphasizing the life-like form of the structures produced. This cannot be classed under the Liesegang heading, strictly speaking, as no colloid was present, but it is now evident that the porous paper was, in effect, a colloid substitute. Because of the detailed investigations carried on by Liesegang, who has published more than forty papers on the subject, periodic banding in the pre- sence of a colloid is known as the Liesegang phen- omenon, though the actusd priority of other claimants in the field is not denied. 5. Production of the Liesegang Phenomenon . Liesegang (1,2) first noted periodic precipi- tates while staining histological specimens by Golgi's method. Golgl's silver method is used for demonstrating the shape and relationship of neurons. The method consists essentially of immersing fresh pieces of nervous tissue first in a solution con- taining potassium dichromate (and usually osmlc salt), and then in silver nitrate. A black deposit of a reduced silver salt is formed in and aro\md the processes and cell-bodies of many of the neurons. (178, p. 544.) In general, the method of preparation consists in using a solution of one of the reacting sub- stances made up with enough gelatin to form a gel. After gel formation, either a drop of strbng solu- tion or a crystal of the other reacting substance is placed at a point on the gel, and from this point permeates the gel in all possible directions. Often the experiment is carried out in a test tube. In such a case bands or discs of precipitate are form- ed at successive depths in the tube. When a flat plate is used, successive circles of precipitate form about the drop or crystal of the second re act ant (9, pp. 12-3). Gels other than gelatin may b© used (10, 11, 12, which have 13, 14, 15, 16, 17, 18). Among those been used might be mentioned silica gel (11, 14, 15, starch and 18), agar gel (12, 14, 16, 17, 18), various hydroxides (14). Lloyd and Moravek (19) report banding of certain precipitates in all of three gels, viz., starch, agar and gelatin gels. two Rlegel (20) reports banding from contact of silica gels containing the reacting substances. and Cases are known in which only one substance the colloid are present. Davies (21) reports 5 rhythmic bands of dyes on filter paper, cotton cloth and unglazed porcelain, obtained bjt regulated evap- oration. Coplsarow (22) obtains rhythmic precip- itates by the diffusion of picric acid, tannic acid, lactic acid, phenol, phosphoric acid, or alpha-trl- nltrotoluene into gelatin gel. Dhar and Mlttra (23) obtain periodic precipitates in the slow coagulation of ferric hydroxide, chromic hydroxide and stannic hydroxide by tmlvalent electro- lytes such as potassium chloride and sodium bromate. In general, when a reaction resulting in pre- cipitation or coagulation takes place within a gel (or within a colloid substitute), Llesegang structures may result. 4. Influence of Various Conditions on the Llesegang Phenomenon . a. Influence of Concentration . K6hler (24) states that the bands are blurred when the react ants are too concentrated, and that, on the other hand, when the react ants are
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