THE OXIDATION OF STARCH \tiTH ALKALINE HYPOCHLORITE A Thesis by Allan Alfred Eisenbraun Submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy McGill University March 1959 ACKNOVJLEDGEMENTS The author wishes to express his sincere gratitude to Professer C.B. Purves for his capable direction, constant interest and encouragement throughout this investigation. Grateful acknowledgement is further made to the Gottesman Corporation of New York, for financial assistance in the form of a scholarship. The author also wishes to express his gratitude to Dr. K.M. Gaver, Director of Research of Ogilvie Flour Mills Co., Ltd., for a generous rearrangement of the company working hours, which enabled him to attend lectures at the University Campus. TABLE OF CONTENTS HISTORICAL INTRODUCTION .•••••••••••••••••••••••••••• page 1 Oxidation of Starch and Simple Sugars with Alkaline Hypochlorite..................... 1 Mechanism of Alkaline Oxidation of Starch and Cellulose ••••••••••••••••••••••••••••• 14 RESULTS AND DISCUSSION ••••••••••••••••••••••••••••••••• 33 Preliminary Oxidations with Calcium Hypochlorite ••• 34 Preliminary Investigation of the Products •••••••••• 44 Recovery and Identification of the Oxidation Products •••••••••••••••••••••••••••••••••• -Preparation of the Calcium Salts ••••.••••••••••• -Hydrolysis and Separation of the Water- Sôluble Calcium Salts ••••••••••••••••••••• 52 -Fractionation and Hydrolysis of the Water Insoluble Calcium Salts ••••••••••••••••••• 75 Significance of the Results and Possible Oxidation Mechanism ••••••••••••••••••••••• EXPERIIVIENTAL • •••••••••••••••••••••••••••••••••••••••••• Preparations •••••••••••••••••••.••••.•••••••••••••• -Wheat Starch .....•..........•..•..•..........•.• -Brucine-D-Erythronate ••••••••••••••••••••••••••• -D-Erythronolactone •••••••••••••••••••••••••••••• -Sodium Calcium Glyoxylate ••••••••••••••••••••••• -Barium Glyoxylate ••••••••••••••••••••••••••••••• 90 -Glyoxylic Acid •••••••••••••••••••••••••••••••••• 92 -Glyoxylic Acid 2,4-Dinitrophenylhydrazone ••••••• 93 -D-Glucuronic Acid ••••••••••••••••••••••••••••••• 94 II Analytical Methods ••••••••••••••••••••••••••••••.• 95 -Hypochlorite ••••••••••••••••••••••••••••••••••• 95 -Carbonated Ash •••.••••••••••••••••••••••••••••• 95 -Sulphated Ash•••••••••••••••••••••••a•••••••••• 96 -Cale ium . ...•........••.•.....................•• 96 -Sodium .............•..........................• 96 -Sodium Periodate and Periodic Acid ••••••••••••• 96 -Iodic Acid and Iodates in the Absence of Periodate •••••••••••••••••••••••••••••••• 97 -Inorganic Chlorides •••••••••••••••••••••••••••• 97 -Inorganic Carbonates ••••••••••••••••••••••••••• 97 -Uronic Anhydride •..... .••...•.....••••••.•.••• 98 ~ -Pentosan •••••••••••••••••••••••••••••••••••• 99 ~·· -Permanganate Oxidation Equivalent •••••••••••••• lOO -Copper Reducing Sugars ••••••••••••••••••••••••• lOO -Neutralization Equivalent •••••••••••••••••••••• 101 -Paper Chromatography ••••••••••••••••••••••••••• 101 Preliminary Oxidations with Calcium and Sodium Hypochlorite •••••••••••••••••••••• 102 Preliminary Investigation of the Products ••••••••• 105 Recovery and Identification of the Oxidation Products ••••••••••••••••••••••• 113 -Preparation of the Calcium Salts ••••••••••••••• 113 -Hydrolysis and Separation of the Water- Solub1e Calcium Salts •••••••••••••••••••• 118 -Fractionation and Hydrolysis of the Water-Insoluble Calcium Salts •••••••••••• 142 AND CLAIMS TO ORIGINAL RESEARCH ••••••••• ••••• 146 SUM~RY ~ BIBLIOGRAPHY ••••••••••••••••••••••• ;·.. • • • • • • • • • • • • • • • • 148 III LIST OF TABLES No. Page I Preliminary Oxidation of Starch with Hypochlorite .•••.••.••••••••••••••••••••• 36 II Oxidation of Starch with 5.5 Molar Ratio of Hypochlorite •••.••••••••••••••••••••• 40 III Oxidation of Starch with Sodium Hypochlorite •••••••••.•••••••••••••••••••••••• 45 IV Chromatography of Hydrolysate from Fraction II •••••••••••••••••••••••••••••• 56 V Column Chromatography of Oxystarch Hydrolysate on Dowex 1-x-4 •••••••••••••••••••• 61 VI Paper Chromatography of Hydro1ysed Fraction la. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 VII Hydro1ysis of Fraction II with N Sulphuric Acid •••.•••••••••••••••••••••••••• 120 VIII Hydro1ysis of Fraction II with N Su1phuric Acid over a Prolonged Period •••••••••••••••••• 121 IV LIST OF FIGURES No. f'age la Oxidation of 0.183 base molar starch solution with 1.33 volumes of 0.756 M calcium hypochlorite .•.••••••••••••••••••••••••• lb Oxidation of 0.183 base molar starch solution with 1.33 volumes of 0.756 M calcium hypochlorite. Ordinates log ratio of initial to remaining concentration of hypochlorite •••••• 39 2 Hydrolysis of oxystarch with boiling N sulphuric acid ..........•...................•• 53 3 Hydrolysis of oxystarch with boiling N sulphuric acid over a prolonged period •••••••••••••••••••• 54 4 Separation of sugar acids from hydrolysis of oxystarch by ion exchange chromatography •••••••• 72 GENERAL INTRODUCTION The oxidation of starch and cellulose with alkaline hypochlorite is of considerable industrial interest. Starches oxidized with this reagent have wide application in the sizing of textile fibers and paper. Alkaline hypochlorite is also widely used in the bleaching of cellulose pulp. In this study, starch rather than cellulose was chosen, as in cellulose the factor of inaccessibility might have introduced unnecessary complications. The first object of this work was the isolation of the oxidized starch and by products in highest yields possible, so that most of the oxidant could be accounted for. The second object was the investigation of the reaction mechanism, a task which involved the isolation and identification of the individual degradation products. About 80% of the oxidizing power of the hypochlorite consumed was represented by carbon dioxide and carboxylic acid groups. Methods of hydrolysis plus paper and rather large-scale column chromatography were developed, which made it possible VI to separate and identify the other oxidation products as D-, Dl and meso-tartaric acid, D-glucuronic acid, D-erythrono lactone and glyoxylic acid. A new method of preparing the latter substance was incidentally discovered. HISTORICAL INTRODUCTION Oxidation of Starch and Simple Sugars with Alkaline Hypohalite Sodium hypoiodite has been used for a very long time to oxidize aldoses stochoimetrically to aldonic acids (1) according to the equation: RCHO .,. I2 + 3 NaOH ---? RCOONa + 2 Nai + 2~ 0 Goebel (2) prepared D-gluconic and D-maltobionic acids by the treatment of the corresponding aldoses with barium hypoiodite. Hoenig and Rusiczka (3} oxidized both D-glucose and D-galactose to the corresponding aldonic acids with alka line barium hypobromite in 83% and 87% yield, using ultra violet light as a catalyst. These authors noted that the formation of aldonic acids was favoured by low concentrations of alkali and sugar. When barium hypobromite was replaced by calcium hypochlorite, the reaction was slower and the yields were reduced to 61 and 58%. Hoenig and Tempus (4) studied the prolonged action of barium hypobromite on D-glucose. · 2 These authors thought that in the course of this reaction first D-gluconic, then 2-keto-D-gluconic and finally D-arabonic acids were formed. Reichstein and Neracher (5) disputed these results and claimed that the main product was 5-keto- D-gluconic acid and not the 2-keto acid, since the former keto-acid could be further oxidized to D-xylo-trihydroxy- glutaric acid. Smolenski (6) oxidized with methyl~D-glucopyranoside bromine using sodium carbonate as a buffer, and isolated the brucine salt of methyl-D-glucuronide in 30% yield. Jackson and Hudson (7) oxidized methyl-~-D-mannopyranoside with 8 equivalents of bromine in barium hydroxide solution and isolated D-methoxy-D-hydroxy-methyl-diglycolic acid (I) and the methyl~-glycoside of D-mannuronic acid (II) in 25% and 12% yields as their strontium and brucine salts. The H H'\_/OCH \/OCH 3 3 G gOOH 1 1 HO-~-H HO- -H 0 c~ H-Li-OH 1 H-é H-~ éH 0H OOH 2 I II formation of these compounds showed that alkaline hypobromite sometimes oxidized secondary alcohol groups in such a manner