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25 Ml) and Bromoethane (25 Ml) Were Mixed in a 100 Ml Round Bottom Flask

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25 Ml) and Bromoethane (25 Ml) Were Mixed in a 100 Ml Round Bottom Flask ABSTRACT HEIDI L. VERMEULEN. The Synthesis of Deuterated Bromodichloromethane, Deuterated Chlorodibromomethane, and Mixed Halogenated Acetic Acids. (Under The Direction of Dr. Avram Gold) The purpose of this research project was to develop procedures for the preparation of isotopically-labeled, mixed halogenated disinfection by-products. Deuterated bromodichloromethane (deuterated BDCM), was synthesized using an aluminum catalyzed reaction. Equal volumes of deuterated chloroform (25 mL) and bromoethane (25 mL) were mixed in a 100 mL round bottom flask. Enough AICI3 was added to the flask such that the reaction mixture turned dark red in color. The reaction was allowed to stir for 46 hours. The product was purified through fractional distillation, in which three fractions were collected. Through GC-MS analysis, the purity of fraction 2 (65 - 72 °C) was calculated to be 93 % and that of fraction 3 (73 - 78 °C) was 85%. For both fractions, BDCM was 99% deuterium enriched. "C NMR and GC-MS analyses indicated that the impurity in both of fractions 2 and 3 was deuterated chlorodibromomethane. This indicated that AICI3 was reacting with the generated deuterated BDCM to yield deuterated chlorodibromomethane. Therefore, by letting this same reaction stir for 7 days it was possible to obtain a significant amount (approximately 5 g) of deuterated chlorodibromomethane. Bromochloro-, chlorodibromo-, and bromodichloroacetic acid were all obtained through a literature synthesis (Zimmer et al., 1990). A new experimental procedure was developed for the synthesis of bromodichloroacetic acid (CBrCl2C00H). Allowing bromodichloromethane to react with 1.6 M n-butyllithium in hexanes, yielded the bromodichloromethide anion. The anion was carboxylated by the addition of dry ice to yield CBrCl2C02"Li"^. The lithium salt was added to water and acidified with concentrated hydrochloric acid. CBrCl2COOH was extracted from solution with methylene chloride. Having demonstrated the feasibility of this reaction, attempts were made to develop a procedure based on Ba^'^COs as a source of CO2. Pilot studies involving BaC03/H2S04 as the CO2 source proved unsuccessful. While using unrealistic quantities of BaCOj (5 g), only trace quantities of bromodichloroacetic acid were obtained. Table of Contents Page List of Figures........................................................... i List of Tables............................................................. ii Acknowledgements....................................................... iii L Literature Review......................................................... 1 A. Disinfection............................................................ 1 B. Bromodichloromethane (BDCM)................................... 4 1. Chemical and Physical Properties............................... 4 2. Occurrence and Prevalence...................................... 5 3. Metabolism......................................................... 7 4. Toxicity.............................................................. 9 a. Hematological Effects........................................... 10 b. Hepatic Effects................................................... 10 c. Renal Effects..................................................... 11 5. Carcinogenicity.................................................... 12 C. Halogenated Acetic Acids.......................................... 13 1. Chemical and Physical Properties.............................. 13 2. Occurrence and Prevalence...................................... 14 3. Metabolism.......................................................... 16 4. Toxicity.............................................................. 19 5. Carcinogenicity..................................................... 22 n. Introduction............................................................... 26 in. Experimental Materials and Methods.................................. 29 A. Instrumentation and Laboratory Materials........................ 29 B. Synthesis of Mixed Halogenated Acetic Acids................... 30 1. Bromochloroacetic Acid........................................... 30 2. Chlorodibromoacetic Acid........................................ 31 3. Bromodichloroacetic Acid........................................ 32 a. Literature Synthesis............................................. 32 b. Synthesis through Lithium Salt Formation................. 33 C. Synthesis of Deuterated Bromodichloromethane................ 34 D. Synthesis of Deuterated Chlorodibromomethane................ 36 IV. Results and Discussion .................................................. 37 A. Mixed Halogenated Acetic Acids................................... 37 B. Deuterated Bromodichloromethane.................................. 39 1. Lithium Salt Formation........................................... 39 2. Bromination of Dichloromethide Anion........................ 40 Page 3. Hydrogenolysis of Dibromodichloromethane.................. 41 4. Aluminum Chloride Catalyzed Reaction........................ 42 5. Redistribution of Halogens in a Mixture of Chloroform and Bromoform Under Alkaline Conditions.................... 45 V. Conclusions............................................................... 48 VI. References................................................................. 51 List of Figures Figure Page 1 Chemical Structures of THMs.......................................... 58 2 Carbon Centered Oxidation Metabolic Pathway for THMs....... 59 3 Halogen Centered Oxidation Metabolic Pathway for THMs..... 60 4 Reductive Metabolic Pathway for THMs............................ 61 5 Reaction Scheme for CHClBrCOOH................................. 62 6 Mass Spectrum of CHClBrCOOH.................................... 63 7 Reaction Scheme for CClBr2C00H.................................. 64 8 Mass Spectrum of CClBrzCOOH...................................... 65 9 Reaction Scheme for CClaBrCOOH.................................. 66 10 Mass Spectrum of CClzBrCOOH..................................... 67 11 Reaction Scheme for CCl2BrC00H via Lithium Salt Formation................................................................. 68 12 Mass Spectrum of CCl2BrCOOH from Li Salt Reaction......... 69 13 Proposed Reaction Scheme for ^^C-labeled CCl2BrC00H....... 70 14 Reaction Scheme for Deuterated BDCM (AICI3 Reaction)....... 71 15 *^C NMR of Deuterated BDCM Fraction 2......................... 72 16 '^C NMR of Deuterated BDCM Fraction 3......................... 74 17 GC-MS of Deuterated BDCM Fraction 2........................... 76 18 GC-MS of Deuterated BDCM Fraction 3........................... 77 19 Reaction Scheme for Deuterated Chlorodibromomethane (CDBM)................................................................... 78 20 "C NMR of Deuterated BDCM Fraction 2 (7 Day AICI3 Catalyzed Reaction).................................... 79 21 "C NMR of Deuterated BDCM Fraction 3 (7 Day AICI3 Catalyzed Reaction).................................... 81 22 "C NMR of Deuterated BDCM and CDBM Fraction 4 (7 Day AICI3 Catalyzed Reaction).................................... 83 23 "C NMR of Deuterated BDCM and CDBM Fraction 5 (7 Day AICI3 Catalyzed Reaction).................................... 85 24 Proposed Reaction Scheme for Deuterated BDCM Via Lithium Salt Formation........................................... 87 25 "C NMR of BDCM From Lithium Salt Reaction................. 88 26 Mass Spectrum of Deuterated BDCM From Lithium Salt Reaction.............................................................. 90 27 Proposed Reaction Scheme for Deuterated BDCM Via Bromination of Dichloromethide Anion........................ 91 28 Proposed Reaction Scheme for Deuterated BDCM Via Lithium Aluminum Deuteride.................................... 92 29 Generation of Dichlorocarbenes Under Catalytic Two-Phase Conditions.................................................. 93 30 Reaction Scheme for BDCM Via Mixing Chloroform and Bromoform Under Alkaline Conditions......................... 94 List of Tables Table Page 1 Haloacids Identified as Drinking Water Chlorination By-Products in a Ten-City Survey................................... 95 2 Quarterly Median Values for Haloacetic Acids in U.S. Drinking Waters.............................................. 96 3 Cancer Incidence in Mice Exposed to Chloroacetic Acids in Drinking Water.............................................. 97 4 Melting Points of Mixed Halogenated Acetic Acids.............. 98 5 Mass Spectral Data For Mixed Halogenated Acetic Acids and Deuterated BDCM............................................... 99 6 '^C NMR Chemical Shifts........................................... 100 11 ACKNOWLEDGEMENTS I would like to sincerely thank Dr. Gold for all of his guidance and support throughout this entire project. He has been an excellent research and academic advisor, and has made my educational experience here at the University of North Carolina a pleasant one. I would like to give special thanks to Dr. Sangaiah. He has been a true inspiration for the past two years. I am indebted to him for his vast knowledge in organic chemistry. I am also very thankful to have shared a laboratory with two very fine scientists, Dr. Jayaraj and soon to be Dr. Rachel Austin. Their insights and support throughout this project have been greatly appreciated. I would also like to thank Dr. Ball and Dr. Christman for being on my research committee. I am very thankful for all of their help and guidance both in my research and in writing my masters technical report. In
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