Biorenewable Materials from Isosorbide Michael Dennis Zenner Iowa State University
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Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2015 Biorenewable materials from isosorbide Michael Dennis Zenner Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Organic Chemistry Commons Recommended Citation Zenner, Michael Dennis, "Biorenewable materials from isosorbide" (2015). Graduate Theses and Dissertations. 16095. https://lib.dr.iastate.edu/etd/16095 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 Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Biorenewable materials from isosorbide by Michael D. Zenner A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Organic Chemistry Program of Study Committee: Jason S. Chen, Co-Major Professor Michael R. Kessler, Co-Major Professor Levi M. Stanley Arthur H. Winter Javier Vela Iowa State University Ames, Iowa 2015 Copyright © Michael D. Zenner, 2015. All rights reserved ii To my wife, Ashley. Without you this wouldn’t have been possible. Thank you. iii TABLE OF CONTENTS Page ACKNOWLEDGEMENTS iv ABSTRACT v CHAPTER 1: INTRODUCTION: SUSTAINABLITY AND ISOSORBIDE 1 CHAPTER 2: ISOSORBIDE-BASED DIISOCYANATES AND POLYURETHANES THEREOF 11 – 51 Introduction 11 Results and Discussion 12 Conclusion 22 Experimental Section 22 References 45 CHAPTER 3: UNEXPECTED TACKIFIERS FROM ISOSORBIDE 46 – 72 Introduction 46 Results and Discussion 47 Conclusion 54 Experimental Section 55 References 71 CHAPTER 4: DIVERGENT THERMAL POLYMERIZATION PATHWAYS OF TWO ISOSORBIDE-MALEIC ACID DERIVATIVES 72 – 88 Introduction 72 Results and Discussion 73 Conclusion 79 Experimental Section 79 References 87 CHAPTER 5: CONCLUSION AND FUTURE DIRECTIONS 89 – 90 iv ACKNOWLEDGEMENTS I would like to thank my committee chairs, Jason Chen and Michael Kessler, and my committee members, Levi Stanley, Arthur Winter and Javier Vela, for their guidance and support throughout the course of my research. In addition, I would also like to thank my friends, colleagues, the department faculty and staff for making my time at Iowa State University a wonderful experience. I would like to thank my advisors, Jason Chen and Michael Kessler. It was with your guidance and encouragement that got me to where I am today. My collaborator, Samy Madbouly, for his rheological contributions to our publications. I would also like to thank my research assistants Cory Barnish and Nick Tucker. I couldn’t have asked for better, harder working colleagues. v ABSTRACT As petroleum feedstocks start to dwindle, it is becoming more important to find acceptable replacements for materials made from these feedstocks. Polyurethanes have classically been synthesized from petroleum-based feedstocks, and depending on its properties, polyurethanes can be used in everything from foams, to construction plastics. In recent years there has been an increasing amount of research trying to replace petroleum-based chemicals those derived from biobased sources. One such compound, isosorbide, is a rigid diol that has seen an increasing amount of research as a replacement for hard segments of polymers. While there has been much work incorporating isosorbide into polyurethanes as a diol, there has been relatively little work incorporating isosorbide as a diisocyanate. Previously, isosorbide has been directly functionalized via and SN2 and oxidation-reduction method. Our approach introduced a tether, succinic anhydride, which is increasingly produced through fermentation. Reaction of isosorbide with succinic anhydride results in a dicarboxylic acid that can be subsequently converted to a diacid chloride. The diacid chloride then undergoes a two-step Curtius Rearrangement to afford an isosorbide-based diisocyanate. Subsequent proof of concept polyurethanes were synthesized and characterized to analyze the properties of our newly synthesized diisocyanate. Tackifiers are a relatively unknown class of molecules that are used extensively in the adhesives industry. Usually derivatives of resin acids (diterpenes), terpenes, or petroleum-based starting materials, tackifiers, are used to improve wetting, tack and adjust the glass transition temperature of an adhesive. While most small molecules are crystalline and have a very distinctive transition from a solid to a liquid, tackifiers are glassy amorphous small molecules that have a glass transition, like a polymer. Tackifiers are usually blend with block copolymers to form pressure sensitive adhesives, i.e. tape. vi It was during the synthesis of our biorenewable diisocyanate that we discovered a molecule which possessed interesting properties. The succinate diacid derivative of isosorbide was extremely viscous and therefore difficult to transfer to the next reaction. It also made everything it touched extremely sticky. With this interesting result, several analogs were synthesized to gain some insights into this emergent property. Increasing the tether length attached to isosorbide by one methylene group had no effect on how tacky the material was, but shifted the temperature at which it was most tacky down by approximately 30 °C. Conversely, introducing rigidity into the tether, increased the temperature of max tack by 30 °C. We believed the carboxylic acids of the tethers were contributing to this emergent property of tack, therefore methyl ester derivatives were synthesized and tested. While the max tack temperature shifted, there was little to no effect on maximum tack of these molecules. Further derivatives are being investigated to hopefully gain insights into the structural aspects of these molecules that are leading to tack. The extra functionality (internal alkene) of our maleate-based tackifier led us to investigate the ability to make “smart” tackifiers, by either permanently or reversibility converting our tackifier using an external stimuli, such as heat or UV-light. Two proof of concept polymers were synthesized, one from a maleate diacid-based monomer and the other from a maleate methyl ester- based monomer. Interestingly, we discovered these monomers polymerize at significantly different temperatures and result in varying morphology. This led us to investigate the polymerization of our diacid-based polymerization. It was discovered, using 1H NMR, FTIR, and GPC studies, that our diacid-based tackifier was polymerizing through a condensation mechanism rather than through a radial mechanism. 1 CHAPTER 1 SUSTAINABILITY AND ISOSORBIDE 1.1 Sustainability Historically, since the late 1980’s to early 2000’s, crude oil prices remained relatively stable at $30 to $40 per barrel. It was during the early 2000’s that the United States saw an almost exponential increase in price per barrel, stabilizing around $100 in the last few years. According to the U.S. Energy Information Administration, oil prices have been project to follow one of three project routes, see Figure 1. If prices continue on the current trend, oil prices are expect to reach $200 per barrel by 2040. This would result in doubling, or more, of the price seen at the pump circa 2010. A second projection has oil prices reaching $150 per barrel by 2040, which is still an increase of 50% over the next 30 years. Finally, most optimistically and least likely, stabilization around current price would result in gas prices competitive to that of prices around 2010. While the general public mostly associates high oil prices with high prices at the gas pump, many does not make the link between high oil prices with the cost of commodity chemicals. Today, a Figure 1: historical and predicted oil prices. large majority of chemicals that go into things such as plastic bottles and packaging are still derived from petroleum feedstocks.[1] This need for alternative chemicals for use in materials has led to two different approaches when it comes to replacement of petroleum–based materials. The first, is production and replacement of petroleum based chemicals with those produces from renewable resources.[2,3] This allows for an easy transition from the stand point of being a drop-in replacement since there would 2 be no difference in structure or properties of the end product. The second route is the synthesis and incorporation of bio-based chemicals with new structures, and potential properties.[4] For the purposes of this discussion, we are going to focus on the latter. Within the field of using new, biorenewable, chemicals there are two main subcategories, those who are making new materials from natural sources, such as cellulose, with little to no chemical modification and those converting biofeedstocks into more refined chemicals. One example, is finding new uses for cellulose through new processing technology with no chemical modification.[5] While appealing, the use of cellulose has two major draw backs that severely limits its use. First, cellulose has low thermal stability, therefore use in any high temperature application is not feasible, and secondly, the high functionality (alcohol groups) makes cellulose a poor choice in environments where alcohol reactivity could occur. Reaction of the alcohols on cellulose could result in alteration of its chemical and physical properties, something usually avoided when used for a