PEG基氮氧自由基嵌段共聚物的制备及其对伯醇的催化氧化性能
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摘要
以溴化的聚乙二醇(PEG)为大分子引发剂,甲基丙烯酸2,2,6,6-四甲基哌啶醇酯(TMPM)为单体,通过电子转移活化再生催化剂原子转移自由基聚合(ARGET ATRP),得到PEG-PTMPM嵌段共聚物,然后经过3-氯过氧苯甲酸氧化,得到含氮氧自由基的嵌段共聚物(PEG-PTMA)。分别制备了两种嵌段共聚物MPEG-PTMA和PTMA-PEG-PTMA。在NaClO水油两相氧化体系下,研究了嵌段共聚物结构对伯醇选择性催化氧化性能的影响。结果表明,PEG链段和PTMA链段分子量以及嵌段共聚物类型均会影响催化性能,PEG分子量为2000的嵌段共聚物的活性甚至优于未负载的小分子TEMPO,对苯甲醇的转化率可达100%,对其它伯醇的转化率也在95%以上。嵌段共聚物回收方便,重复使用5次活性未见明显降低。
Block copolymer PEG-PTMPM was synthesized via activator regenerated by electron-transfer atom-transfer radical polymerization(ARGET ATRP) with brominated polyethylene glycol(PEG) as a macromolecular initiator and 2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate(TMPM) as a monomer. It was then reacted with m-chloroperbenzoic acid to prepare nitroxyl block copolymer of PEG-PTMA. The prepared block copolymers included diblock copolymer of MPEG-PTMA and triblock copolymer of PTMA-PEG-PTMA. Effects of copolymer structure on selective catalytic oxidation of primary alcohols in a biphasic water-oil Na Cl O oxidation system were studied. The results show that molecular weight of PEG and PTMA segments and the block copolymer type can affect catalytic performance. The activity of block copolymer with PEG2000 as the supporting segment is better than that of non-supported TEMPO, and the benzyl alcohol conversion rate can reach to 100%. Other primary alcohol conversions are also over 95%. Furthermore, these nitroxyl block copolymers have excellent recyclability and the activity is not significantly decreased after 5 cycles.
Block copolymer PEG-PTMPM was synthesized via activator regenerated by electron-transfer atom-transfer radical polymerization(ARGET ATRP) with brominated polyethylene glycol(PEG) as a macromolecular initiator and 2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate(TMPM) as a monomer. It was then reacted with m-chloroperbenzoic acid to prepare nitroxyl block copolymer of PEG-PTMA. The prepared block copolymers included diblock copolymer of MPEG-PTMA and triblock copolymer of PTMA-PEG-PTMA. Effects of copolymer structure on selective catalytic oxidation of primary alcohols in a biphasic water-oil Na Cl O oxidation system were studied. The results show that molecular weight of PEG and PTMA segments and the block copolymer type can affect catalytic performance. The activity of block copolymer with PEG2000 as the supporting segment is better than that of non-supported TEMPO, and the benzyl alcohol conversion rate can reach to 100%. Other primary alcohol conversions are also over 95%. Furthermore, these nitroxyl block copolymers have excellent recyclability and the activity is not significantly decreased after 5 cycles.
引文
[1]LIU Lin(刘霖),SUN Zhen(孙真),LI Luo-dan(李罗丹),et al.Selective aerobic oxidation of alcohols catalyzed by polystyrene-suppored TEMPO(聚苯乙烯负载TEMPO催化醇的选择性氧化)[J].Journal of Huaihai Institute of Technology(Natural Science Edition)(淮海工学院学报(自然科学版)),2010,19(4):31-33.
[2]Yu Y L,Gao B J,Li Y F.Immobilized 2,2,6,6-tetramethyl-piperidinyl-1-oxy catalyst on polymer microspheres and its catalytic oxidation of benzyl alcohol with molecular oxygen[J].Chinese Journal of Catalysis,2014,34(9):1776-1786.
[3]Gao B J,Zhang L Q,Chen T.TEMPO immobilized on polymer microspheres-catalyzed oxidation of cyclohexanol by molecular oxygen[J].Chinese Journal of Catalysis,2015,36(8):1230-1236.
[4]SU Ling(苏玲),ZHANG Yue-cheng(张月成),ZHAO Ji-quan(赵继全).Synthesis of dendritic polyamidoamine supported2,2,6,6-tetramethylpiperidine-1-oxyl and its catalytic performance on the oxidation of alcohols with molecular oxygen as oxidant(树枝状聚酰胺胺负载TEMPO的合成及其催化分子氧氧化醇的性能)[J].Journal of Molecular Catalysis(China)(分子催化),2014,28(5):400-409.
[5]Ferreira P,Hayes W,Phillips E,et al.Polymer-supported nitroxyl catalysts for selective oxidation of alcohols[J].Green Chemistry,2004,6(6):310-312.
[6]Ferreira P,Phillips E,Rippon D,et al.Poly(ethylene glycol)-supported nitroxyls:branched catalysts for the selective oxidation of alcohols[J].Journal of Organic Chemistry,2004,69(20):6851-6859.
[7]Ferreira P,Phillips E,Rippon D,et al.Catalytic oxidation of alcohols using molecular oxygen mediated by poly(ethylene glycol)-supported nitroxyl radicals[J].Applied Catalysis B:Environental,2005,61(3-4):206-211.
[8]Benaglia M,Puglisi A,Holczknecht O,et al.Aerobic oxidation of alcohols to carbonyl compounds mediated by poly(ethylene glycol)-supported TEMPO radicals[J].Tetrahedron,2005,61(51):12058-12064.
[9]Pozzi G,Cavazzini M,Quici S,et al.Poly(ethylene glycol)-supported TEMPO:an efficient,recoverable metal-free catalyst for the selective oxidation of alcohols[J].Organic Letters,2004,6(3):441-443.
[10]Nakahara K,Iwasa S,Satoh M,et al.Rechargeable batteries with organic radical cathodes[J].Chemical Physics Letter,2002,359(5,6):351-354.
[11]Saito K,Hirose K,Okayasu T,et al.TEMPO radical polymer grafted silicas as solid state catalysts for the oxidation of alcohols[J].RSC Advances,2013,3(25):9752-9756.
[12]ZHANG Jia-hong(张家宏),LIU Xiao-ning(刘晓宁),ZHONG Yu(仲玉),et al.The boron absorption performance of tentacular hydrophilic hydroxylamine resin prepared via atom transfer radical polymerization(基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究)[J].Journal of Chemical Engineering of Chinese Universities(高校化学工程学报),2014,28(6):1328-1333.
[13]Liu S J,Hu Q Q,Zhao F Q,et al.Nitroxide polymer brushes prepared by surface-initiated ARGET ATRP and their selective oxidation performances[J].Express Polymer Letters,2014,8(11):862-868.
[14]Bugnon L,Morton C J H,Novak P,et al.Synthesis of poly(4-methacryloyloxy-TEMPO)via group-transfer polymerization and its evaluation in organic radical battery[J].Chemistry of Materials,2007,19(11):2910-2914.
[2]Yu Y L,Gao B J,Li Y F.Immobilized 2,2,6,6-tetramethyl-piperidinyl-1-oxy catalyst on polymer microspheres and its catalytic oxidation of benzyl alcohol with molecular oxygen[J].Chinese Journal of Catalysis,2014,34(9):1776-1786.
[3]Gao B J,Zhang L Q,Chen T.TEMPO immobilized on polymer microspheres-catalyzed oxidation of cyclohexanol by molecular oxygen[J].Chinese Journal of Catalysis,2015,36(8):1230-1236.
[4]SU Ling(苏玲),ZHANG Yue-cheng(张月成),ZHAO Ji-quan(赵继全).Synthesis of dendritic polyamidoamine supported2,2,6,6-tetramethylpiperidine-1-oxyl and its catalytic performance on the oxidation of alcohols with molecular oxygen as oxidant(树枝状聚酰胺胺负载TEMPO的合成及其催化分子氧氧化醇的性能)[J].Journal of Molecular Catalysis(China)(分子催化),2014,28(5):400-409.
[5]Ferreira P,Hayes W,Phillips E,et al.Polymer-supported nitroxyl catalysts for selective oxidation of alcohols[J].Green Chemistry,2004,6(6):310-312.
[6]Ferreira P,Phillips E,Rippon D,et al.Poly(ethylene glycol)-supported nitroxyls:branched catalysts for the selective oxidation of alcohols[J].Journal of Organic Chemistry,2004,69(20):6851-6859.
[7]Ferreira P,Phillips E,Rippon D,et al.Catalytic oxidation of alcohols using molecular oxygen mediated by poly(ethylene glycol)-supported nitroxyl radicals[J].Applied Catalysis B:Environental,2005,61(3-4):206-211.
[8]Benaglia M,Puglisi A,Holczknecht O,et al.Aerobic oxidation of alcohols to carbonyl compounds mediated by poly(ethylene glycol)-supported TEMPO radicals[J].Tetrahedron,2005,61(51):12058-12064.
[9]Pozzi G,Cavazzini M,Quici S,et al.Poly(ethylene glycol)-supported TEMPO:an efficient,recoverable metal-free catalyst for the selective oxidation of alcohols[J].Organic Letters,2004,6(3):441-443.
[10]Nakahara K,Iwasa S,Satoh M,et al.Rechargeable batteries with organic radical cathodes[J].Chemical Physics Letter,2002,359(5,6):351-354.
[11]Saito K,Hirose K,Okayasu T,et al.TEMPO radical polymer grafted silicas as solid state catalysts for the oxidation of alcohols[J].RSC Advances,2013,3(25):9752-9756.
[12]ZHANG Jia-hong(张家宏),LIU Xiao-ning(刘晓宁),ZHONG Yu(仲玉),et al.The boron absorption performance of tentacular hydrophilic hydroxylamine resin prepared via atom transfer radical polymerization(基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究)[J].Journal of Chemical Engineering of Chinese Universities(高校化学工程学报),2014,28(6):1328-1333.
[13]Liu S J,Hu Q Q,Zhao F Q,et al.Nitroxide polymer brushes prepared by surface-initiated ARGET ATRP and their selective oxidation performances[J].Express Polymer Letters,2014,8(11):862-868.
[14]Bugnon L,Morton C J H,Novak P,et al.Synthesis of poly(4-methacryloyloxy-TEMPO)via group-transfer polymerization and its evaluation in organic radical battery[J].Chemistry of Materials,2007,19(11):2910-2914.