摘要
二氧化碳(CO2)的利用和捕集已经成为世界范围内备受关注的战略性研究课题。在CO2参与的众多反应中,与环氧烷烃共聚反应是最有潜力的绿色聚合过程之一。该领域的研究重点是选择性催化制备高分子量和高碳酸酯结构单元含量的聚合物,而更具挑战性的研究内容则是如何有效地调控聚合产物的性能及其立体化学。本论文研究了环氧苯乙烷与CO2的不对称交替共聚,重点从聚合产物区域规整性和立构规整性的精确调控以及热力学性能的稳定提高方面开展以下工作:
针对环氧苯乙烷/CO2共聚物微结构(区域规整性和立构规整性)归属尚不清楚的问题,论文首先以外消旋2-甲氧基-1-苯基乙醇和2-甲氧基-2-苯基乙醇为反应底物,合成了三种不同连接方式的二元寡聚碳酸苯乙烯酯模型化合物,并通过碳核磁共振研究明确地表征了环氧苯乙烷/CO2交替共聚物的区域规整性;以外消旋环氧苯乙烷水解动力学拆分及羟基保护合成的手性2-甲氧基-2-苯基乙醇和2-甲氧基-1-苯基乙醇为反应原料,制备了十种具有不同手性中心排布方式的二元寡聚碳酸苯乙烯酯模型化合物,并通过其碳核磁共振研究,为评价环氧苯乙烷/CO2共聚物的立构规整性建立了数据平台。
将衍生化的联-2-萘酚和大位阻金刚烷基团同时引入Salen配体,合成出一种多手性位点的SalenCo(Ⅲ)X配合物作为主催化剂,以2,4-二硝基苯酚化双(三苯基正膦基)亚铵(PPN-DNP)为助催化剂,组成的具有双功能协同作用的催化体系,在温和条件下就能实现(R)-环氧苯乙烷与CO2的不对称、区域和立体选择性交替共聚反应。利用建立起的环氧苯乙烷/CO2共聚物微结构表征数据平台,评价制备出的聚碳酸苯乙烯酯产物,发现其具有良好的区域规整性和立构规整性。聚合物的头-尾连接单元含量为92.2%,立构规整度为96.0%。通过差示扫描量热法(DSC)对上述聚合物热力学性能研究发现,其抗热形变能力较无规聚碳酸苯乙烯酯有一定的提高,玻璃化转变温度(Tg)从80℃提高到90℃。
Utilization and capture of carbon dioxide (CO2) has become a strategic research topic which drew much worldwide attentions. The alternating copolymerization of epoxides and CO2produce biodegradable polycarbonates is one of the most attractive processes for the transformation of CO2due to its economic and environmental benefits. The catalytic synthesis of polycarbonates with high molecular weight and high carbonate linkages is one of the most important issues, while the accurate control of polymer properties and its stereochemistry remains challenge. This dissertation focuses on the asymmetric regio-and stereo-selective alternating copolymerization of styrene oxide and CO2with emphasis of regio-and stereochemistry, and thermodynamic properties.
Concerning on the issue that micro structures (regio-and stereo-chemistry) of copolymer from styrene oxide and CO2have not been identified clearly, three kinds of model compounds bearing different linkages were synthesized from racemic2-methoxy-2-phenylethanol and2-methoxy-1-phenylethanol. Therefore, the regional regularity of the copolymer from styrene oxide and CO2was characterized explicitly by the13C NMR studies of those model compounds. Ten kinds of model compounds with different stereochemistry were synthesized to simulate carbonate unit sequence using chiral2-methoxy-2-phenylethanol and2-methoxy-1-phenylethanol as substrates, which prepared by hydrolytic kinetic resolution of racemic styrene oxide and then protection of the hydroxyl groups. The13C NMR studies of those model compounds provided a data platform to test the microstructures of copolymer from styrene oxide and CO2.
A binary catalyst systems with a SalenCo(III)X complex in which bi(2-naphthol) and bulky sterically hindered adamantyl group were anchored on the ligand framework as catalyst and PPN-DNP as cocatalyst was developed. This catalyst system showed promising activity toward asymmetric regio-and stereo-selective alternating copolymerization of (R)-styrene oxide and CO2under mild conditions. According to the above-established data of microstructural characterization, the synthesized poly (styrene carbonate) has92.2%head-to-tail content and a highly regioregular ring-opening step was observed with a concomitant96.0%retention of configuration. The thermal deformation ability of the above poly (styrene carbonate)(Tg=90℃) has been improved compared with atactic poly (styrene carbonate)(Tg=80℃).
引文
[1]周忠清.二氧化碳催化还原成碳的发展[J].精细石油化工,1994,4:92-96.
[2]贾彦雷,许文,刘家祺.二氧化碳的化学利用[J].天然气化工,2004,29:54-58.
[3]周家贤.二氧化碳开发利用综述[J].化工设计,2004,14(4):7-10.
[4]任伟民.CO2共聚物合成:高活性SalenCo(III)X催化剂设计及聚合反应机理[D].大连:大连理工大学,2010.
[5]金祖铨,吴念.聚碳酸酯树脂及应用[M].北京:化学工业出版社,2009.
[6]彭雪明.CO2与环氧丙烷不对称共聚二元催化体系的设计及合成[D].大连:大连理工大学,2007.
[7]SCHNELL H. Chemistry and Physics of Polycarbonates [M]. John Wiley, New York,1964.
[8]BRUNELLE D J, SMIGELSKI P M, BODEN E P. In Advances in Polycarbonates:Evolution of Polycarbonate Process Technologies [M]. American Chemical Society:Washington, DC,2005.
[9]TSAI W T. Human health risk on environmental exposure to Bisphenol-A [J]. J. Environ. Sci. Health Part C,2006,24:225-255.
[10]INOUE S, KOINUMA H, TSURUTA T. Copolymerization of carbon dioxide and epoxide [J]. J. Polym. Sci., Part B:Polym. Lett.,1969,7:287-292.
[11]Lu X B, DARENSBOURG D J. Cobalt catalysts for the coupling of CO2 and epoxides to provide polycarbonates and cyclic carbonates [J]. Chem. Soc. Rev.,2012, DOI: 10.1039/C1CS15142H.
[12]DARENSBOURG D J. Making plastics from carbon dioxide:Salen metal complexes as catalysts for the production of polycarbonates from epoxides and C02 [J]. Chem. Rev.,2007,107:2388-2410.
[13]时磊.二氧化碳与环氧烷烃的不对称、区域及立体选择性交替共聚[D].大连:大连理工大学,2006.
[14]COATES G W, Moore D R. Discrete metal-based catalysts for the copolymer-rization of CO2 and epoxides:discovery, reactivty, optimization, and mechanism [J]. Angew. Chem. Int. Ed.,2004,43:6618-6639.
[15]CHISHOLM M H, ZHOU Z. Concerning the mechanism of the ring opening of propylene oxide in the copolymerization of propylene oxide and carbon dioxide to give poly (propylene carbonate) [J]. J. Am. Chem. Soc,2004,126:11030-11039.
[16]BLUMENSTEIN J J, MOHAN R S, WHALEN D L. Effects of parasubstituents on the mechanisms of solvolysis of styrene oxides [J]. J. Org. Chem.,1993,58:924-932.
[17]LIN B, WHALENh D L. Stereochemistry of the Spontaneous, Acid-Catalyzed and Base-Catalyzed Hydrolyses of Styrene Oxide [J]. J. Org. Chem.,1994,59: 1638-1641.
[18]GUANG-PENG Wu, SHENG-HSUAN Wei, XIAO-BING LU, et al. Alternating Copolymerization of CO2 and Styrene Oxide with Co (Ⅲ)-based Catalyst Systems:Differences from Aliphatic Epoxides in Reactivity, Polymer Selectivity, and Regioselective Ring-opening [J]. Energy & Environmental Science,2011,4:5084-5092.
[19]DARENSBOURG D J, YARBROUGH J C, FANF C C. Comparative kinetic studies of the copolymerization of cyclohexene oxide and propylene oxide with carbon dioxide in the presence of chromium salen derivatives. In situ FTIR measurements of copolymer vs cyclic carbonate production [J]. J. Am. Chem. Soc.,2003,125:7586-7591.
[20]COATES G W. Precise control of polyolfin stereochemistry using singlesite metal catalyst [J]. Chem. Rev.,2000,100:1223-1252.
[21]KOBAYASHI M, INOUE S, TSURTA T. Diethylzinc-dihydric phenol system as catalyst for the copolymerization of carbon dioxide with propylene oxide [J]. Macromo-lecules,1971,4:658-659.
[22]TAO Y H, WANG X H, CHEN X S, et al. Regio-regular structure high molecular weight poly (propylene carbonate) by rare earth ternary catalyst and lewis base cocatalyst [J]. J. Polym. Sci., Part A:Polym. Chem.,2008,46:4451-4458.
[23]KOBAYASH M, INOUE S, TSURTA T. Copolymerization of carbon dioxide and epoxide by the dialkylzinc-carboxylic acid system [J]. J. Polym. Sci., Part A:Polym. Chem. 1973,11:2383-2385.
[24]SOGA K, IMAI E, HATTORI I. Alternating copolymerization of carbon dioxide and propylene oxide with the catalysts prepared from zinc hydroxide and various dicarboxylic acids [J]. Polym. J.,1981,13:407-410.
[25]CHEN S, QI G R, HUA Z J, et al. Double metal cyanide complex based on Zn3 [Co(CN)6]2 as highly active catalyst for copolymerization of carbon dioxide and cyclohexene oxide [J]. J. Polym. Sci., Part A:Polym. Chem.,2004,42:5284-5291.
[26]TAO Y H, WANG X H, CHEN X S, et al. Regio-regular structure high molecular weight poly (propylene carbonate) by rare earth ternary catalyst and lewis base co-catalyst [J]. J. Polym. Sci., Part A:Polym. Chem.,2008,46:4451-4458.
[27]XIAO-BING LU, YING-JU ZHANG, HUI WANG.Chemical fixation of carbon dioxide to cyclic carbonates under extremely mild conditions with highly active bifunctional catalysts [J]. Journal of Molecular Catalysis A:Chemical 210 (2004) 31-34.
[28]DARENSBOURG D J, BILLODEAUX D R. Aluminum salen complexes and tetrabutyl-ammonium salts:a binary catalytic system for production of polycarbonates from CO2 and cyclohexene oxide [J]. Inorg. Chem.,2005,44:1433-1442.
[29]DARENSBOURG D J, HOLTCAMP M W. Catalytic activity of zinc(Ⅱ) phenoxides which possess readily accessible coordination sites. Copolymerization and terpoly-merization of epoxides and carbon dioxide [J]. Macromolecules,1995,28:7577-7579.
[30]CHENG M, LOBKOVSKY E B, COATES G W, et al. Catalytic reactions involving C1 feed stocks:New highly-activity Zn(II)-based catalysts for the alternating copolymer-rization of carbon dioxide and epoxide [J]. J. Am. Chem. Soc.,1998,120: 11018-11019.
[31]MOORED R, CHENG M, et al. Electronic and steric effects on catalysts for CO2/epoxide polymerization:Subtle modification resulting in superior activity [J]. Angew. Chem. Int. Ed.,2002,41:2599-2602.
[32]BYREN C M, ALLEN S D, et al. Alernating copolymerization of limonene oxide and carbon dioxide [J]. J. Am. Chem. Soc,2004,126:11404-11405.
[33]JESKE R C, ROWLEY J M,. COATES G W. Prerate determining selectivity in the terpolymerization of epoxides, cyclic anhydrides, and CO2:A one-step route to diblock copolymers [J]. Angew. Chem. Int. Ed.,2008,47:6041-6044.
[34]LEE B Y, KWON H Y, LEE S Y, et al. Bimetallic anilido-aldimine zinc complexes for epoxide/CO2 copolymerization [J]. J. Am. Chem. Soc,2005,127:3031-3037.
[35]XIAO Y L, WANG Z, DING K L. Copolymerization of cyclohexene oxide with C02 by using intramolecular dinuclear zinc catalysts [J]. Chem. Eur. J.,2005,11:3668-3678.
[36]KEMBER M R, KNIGHT P D, WILLIIAMS C K. Highly active dizinc catalyst for the copolymerization of carbon dioxide and cyclohexene oxide at one at-mosphere pressure [J]. Angew. Chem., Int. Edit.,2009,48:931-933.
[37]CUI D M, NISHIURA M, HOU Z M. Alternating copolymerization of cyclohexene oxide and carbon dioxide catalyzed by organo rare earth metal complexes [J]. Macromo-lecules,2005,38:4089-4095.
[38]JACOBSEN E N, TOKUNAGA M, LARROW J F. Stereoselective ring opening reactions:W0, 0009436 [P].20000204.
[39]DARENSBOURG D J, MACKIEWICZ R M, et al. Cyclohexene oxide/C02 copolymeri- zation catalyzed by chromium (Ⅲ) salen complexes and N-methyl- imidazole:effects of varying salen ligand substituents and relative cocatalyst loading [J]. Inorg. Chem.,2004,43:6024-6034.
[40]RAO D Y, LI B, ZHANG R, et al. Binding of 4-(N, N-dimethylamino)pyridine to salen-and salan-Cr (Ⅲ) cations:A mechanistic understanding on the difference in their catalytic activity for CO2/epoxide copolymerization [J]. Inorg. Chem.,2009,49: 2830-2836.
[41]LI B, WU G P, REN W M, et al. Asymmetric, regio- and stereo-selective alternating copolymerization of CO2 nd propylene oxide catalyzed by chiral chromium Salan complexes [J]. J. Polym. Sci., Part A:Polym. Chem.,2008,46:6102-6113.
[42]李博.CO2与环氧丙烷交替共聚过程中的区域和立体化学控制[D].大连:大连理工大学,2008.
[43]LI B, ZHANG R, LU X B. Stereochemistry Control of the Alternating Copolymerization of CO2 and Propylene Oxide Catalyzed by SalenCrX Complexes. Macromolecules,2007, 40,2303-2307.
[44]TOKUNAGA M, LARROW J F. Asymmetric catalysis with water:Efficient kinetic resolu-tion of terminal epoxides by means of catalytic hydrolysis [J]. Science,1997, 277:936-938.
[45]QIN Z Q, THOMAS C M, LEE S, et al. Cobalt-based complexes for the copolymerization of propylene oxide and CO2:Active and selective catalysts for polycarbonate synthesis [J]. Angew. Chem. Int. Ed.,2003,42:5484-5487.
[46]LU X B, WANG Y. High activity, binary catalyst systems for the alternating copolymerization of CO2 and epoxides under mild conditions [J]. Angew. Chem. Int. Ed.,2004,43:3574-3577.
[47]NAKANO K, NAKAMURA M, et al. Stereocomplex of poly (propylene carbonate):synthesis of stereogradient poly(propylene carbonate) by regio-and enantioselective copolymerization of propylene oxide with carbon dioxide [J]. Angew. Chem. Int. Ed.,2011,123:4970-4973.
[48]S S, MIN J K. A highly active and recyclable catalytic system for CO2/propylene oxide copolymerization [J]. Angew. Chem. Int. Ed.,2008,47:7306-7309.
[49]JOBI KODIYAN VARGHESE, BUN YEOUL LEE. Incorporation of ether linkage in C02 /propylene oxide copolymerization by dual catalysis [J]. Polyhedron,32(2012) 90-95.
[50]JINA YOO, SUNG JAE NA, BUN YEOUL LEE. Anion variation on a cobalt(Ⅲ) complex of salen-type ligand tethered by four quaternary ammonium salts for CO2/epoxide copolymerization. Dalton Trans.,2010,39,2622-2630.
[51]BO EUN KIM, JOBI KODIYAN, BUN YEOUL LEE. Cobalt (Ⅲ) Complexes of Various Salen-Type Ligand Bearing Four Quaternary Ammonium Salts and Their Reactivity for CO2/Epoxide Copolymerization. Bull. Korean Chem. Soc.2010, Vol.31, No.4.
[52]REN W M, LIU Z W, WEN Y Q, et al. Mechanistic aspects of the copolymerization of CO2 with epoxides using a thermally stable single-site cobalt (Ⅲ) catalyst [J]. J. Am. Chem. Soc.,2009,131:11509-11518.
[53]REN W M, ZHANG X, LIU Y, et al. Highly active, bifunctional Co (Ⅲ)-salen catalyst for alternating copolymerization of CO2 with cyclohexene oxide and terpolymeri-zation with aliphatic epoxides [J]. Macromolecules,2010,43:1396-1402.
[54]WEI-MIN REN, GUANG-PENG WU, XIAO-BING LU. Role of the cocatalyst in the asymmetric coupling of racemic epoxides with C02 using multichiral Co(Ⅲ) complexes:product selectivity and enantioselectivity. Chem. Sci.,2012,3,2094.
[55]何平笙.高聚物的结构与性能[M].北京:科学出版社,2009.
[56]何平笙,杨海洋,朱平平.试论高聚物结构与性能关系的三个层次[J].化学通报,2010年第1期.
[57]NOBUYOSHI NOMURA, RYOHEI ISHII. Stereoselective Ring-Opening Polymerization of a Racemic Lactide by Using Achiral Salen- and Homosalen- Aluminum Complexes [J]. Chem. Eur. J.,2007,13:4433-4451.
[58]王平.高立构规整度高相对分子质量聚乙烯醇的研究[D].山西:中北大学,2010.
[59]LIU B, ZHAO X, WANG X, et al. Copolymerization of carbon dioxide and propylene oxide with neodymium trichloroacetate-based coordination catalyst [J]. Polymer, 2003,44:1803-1808.
[60]REN W M, ZHANG W Z, LU X B. Stereoregular polycarbonate synthesis:alternating copolymerization of CO2 with aliphatic terminal epoxides catalyzed by multichiral cobalt (III) complexes [J]. Sci. China Chem.,2010,53:1646-1652.
[61]NOZAKIi K, NAKANO K, HIYAMA T. Optically active polycarbonates:Asymmetric alternating copolymerization of cyclohexene oxide and carbon dioxide [J]. J. Am. Chem. Soc.,1999,121:11008-11009.
[62]NAKANO K, NOZAKI K, HIYAMA T. Asymmetric alternating copolymerization of cyclohexene oxide and CO2 with dimeric zinc complexes [J]. J. Am. Chem. Soc,2003, 125:5501-5510.
[63]NAKANO K, HIYAMA T, NOZAKI K. Asymmetric amplication in asymmetric alternating copolymerization of cyclohexene oxide and carbon dioxide [J]. Chem. Commun.,2005, 1871-1873.
[64]CHENG M, LOBKOVSKY E, et al. Enantiomerically enriched organic reagents via polymer synthesis:enantioselective copolymerization of cycloalkene oxides and C02 using homogeneous, zinc-based catalysts [J]. Chem. Commun.,2000,2007-2008.
[65]SPASSKY N, MOMTAZ A, KASSAMALY A, et al. Asymmetric synthesis polymerization of meso oxiranes and thiiranes [J]. Chirality,1992,4:295-299.
[66]ARAKAWA H, ARESTA M, ArRMOR J N, et al. Catalysis research of relevance to carbon management:Progress, Challenges, and Opportunities [J]. Chem. Rev.,2001,101: 953-996.
[67]ALLEN S D, BYREN C M, Coates G W. Carbon dioxide as a renewable C1 feedstock: synthesis and characterization of polycarbonates from the alternating copolymerization of epoxides and CO2 [M]. Department of Chemistry and Chemical Biology, Cornell University, American Chemical Society,2006.
[68]ZOU Z Q, JI W D, LUO J X, et al. Copolymerization of carbon dioxide and styrene oxide with double metal cyanide complex [J]. Polymer Material Science and Engineering,2010,26:1-4.
[69]DARENBOURG D J, Fitch S B. An exploration of the coupling reactions of epoxides and carbon dioxide catalyzed by tetramethyltetraazaannulene chromium (Ⅲ) derivatives:formation of copolymers versus cyclic carbonates [J]. Inorganic Chemistry,2008,47:11868-11878.
[70]LEDNOR P W, ROL N C. Copolymerization of propene oxide with carbon dioxide:A selective incorporation of propene oxide into the polycarbonate chains, determined by 100 MHz 13C N. M. R. spectroscopy [J]. Chem. Commun.,1985,598-599.
[71]王献红,王佛松.二氧化碳的固定与利用[M].北京:化学工业出版社,2011.
[72]WITOLD KURAN, TOMASZ Listos. Initiation and propagation reactions in the copolymer-rization of epoxide with carbon dioxide by catalysts based on diethylzinc and polyhydric phenol [J]. Macromol. Chem. Phys.1994,195:977-984.
[73]KOJI NAKANO, KYOKO NOZAKI. Spectral Assignment of Poly [cyclohexene oxide - alt- carbon dioxide] [J]. Macromolecules 2001,34:6325-6332.
[74]COHEN C T, CHU T, COATES G W. Cobalt catalysts for the alternating copolyme-rization of propylene oxide and carbon Dioxide:combining high activity and selectivity [J]. J. Am. Chem. Soc.2005,127:10869-10878.
[75]MALCOLM H. CHISHOLM, ZHIPING ZHOU. Poly(propylene carbonate).1. More about Poly (propylene carbonate) Formed from the Copoly merization of Propylene Oxide and Carbon Dioxide Employing a Zinc Glutarate CataLyst [J]. Macromolecules 2002,35: 6494-6504.
[76]MATTHEW J. BYRNES, MALCOLM H. CHISHOLM, et al. Regioregular and Regioirregular Oligoether Carbonates:A 13C{1H} NMR Investigation [J]. Macromolecules 2004,37: 4139-4145.
[77]KYOKO NOZAKI, KOJI NAKANO. Optically Active Polycarbonates:Asymmetric Alter-nating Copolymerization of Cyclohexene Oxide and Carbon Dioxide [J]. J. Am. Chem. Soc.1999,121:11008-11009.
[78]CHENG M, DATLING N A. Enantiomerically-enriched organic reagent via polymer synthesis:enantioselective copolymerization of cycloalkene oxide and CO2 using homogeneous, zinc-based catalysts. Chem. Commun.2000,2007-2008.