Polymerization of isobutyl vinyl ether(IBVE)has been studied with mononuclear half-titanocene,CpTiCl_3[1]and dinuclear half-titanocenes,[(C_5H_4)_2(CH_2)_n][(TiCl_3)_2][2(n=3),3(n=6)],and[(C_5H_4)_2(CH_2)_n[(TiCl_2OR_...Polymerization of isobutyl vinyl ether(IBVE)has been studied with mononuclear half-titanocene,CpTiCl_3[1]and dinuclear half-titanocenes,[(C_5H_4)_2(CH_2)_n][(TiCl_3)_2][2(n=3),3(n=6)],and[(C_5H_4)_2(CH_2)_n[(TiCl_2OR_2](R=2,6- diisopropylphenoxyl)[4(n=3),5(n=6)],in the presence of methyl aluminoxanes(MAO)as cocatalyst in methylene chloride.The influences of the length of polymethylene brigde and the substitution of aryloxy group at the metal center have been investigated at three polymerization temperature(...展开更多
The interconversion between the two distinct isomers of methyl vinyl ether （MVE）, the formation of the primary ozonides from O3-initated reactions of MVE, the transformation between the primary ozonides, and the sub...The interconversion between the two distinct isomers of methyl vinyl ether （MVE）, the formation of the primary ozonides from O3-initated reactions of MVE, the transformation between the primary ozonides, and the subsequent fragmentation were studied using quantum chemical methods at the BHandHLYP/6311＋＋G（d,p） level of theory for optimized geometries and frequency calculations and at the QCISD/631G（d,p） level for the single point energy calculations. The rate coefficients were calculated for the temperature range 280-440 K by using the canonical transition state theory （TST）. For ozone addition to MVE, there are two different possibilities discussed on the basis of two different possible orientations for ozone attack. The results of the theoretical study indicate that although the synperiplanar-MVE is 7.11 kJ/mol more stable than the antiperiplanar-MVE, the antiperiplanar-MVE plays a more important role in formation of the primary ozonides because the primary ozonides formed from the ozone addition antiperiplanar-MVE are more stable and the energy barriers corresponding to transition states are lower. The intereonversion between the primary ozonides formed from the ozone addition to antiperiplanar-MVE is the most accessible compared with the transformations between other primary ozonides. The cleavage of the primary ozonides mainly leads to the formation of the CH2OO, which is in agreement with the experimental estimates. The calculated overall rate constant for the ozone-initiated reactions is 4.8× 10^-17 cm^3/（molecule.s） at 298.15 K, which agrees with the experimental value for ethyl vinyl ether.展开更多
An efficient and regioselective synthesis of N-9 alkoxyalkylated purine nucleoside derivatives was achieved via the N-alkoxyalkylation of purine rings with vinyl ethers catalyzed by L-ProT.The advantages of this proto...An efficient and regioselective synthesis of N-9 alkoxyalkylated purine nucleoside derivatives was achieved via the N-alkoxyalkylation of purine rings with vinyl ethers catalyzed by L-ProT.The advantages of this protocol include good to excellent yield,mild reaction condition,and simple manipulation.A plausible mechanism for the transformation was given.展开更多
A mild, one-pot procedure for the synthesis of vinyl ethers in good yields from 2-hydroxyalkyl phenyl selenides with primary or secondary organic halides has been developed.
Five fluorine-containing vinyl ether monomers were prepared by the reaction between 2-vinyloxy ethanol, a fluorinated alcohol and hexafluorobenzene in the presence of sodium hydride in dimethylformamide. Two represent...Five fluorine-containing vinyl ether monomers were prepared by the reaction between 2-vinyloxy ethanol, a fluorinated alcohol and hexafluorobenzene in the presence of sodium hydride in dimethylformamide. Two representative properties of these monomers, UV-curing behavior initiated by a cationic photo-initiator PAG 201 and surface free energy of coating films, were investigated. Photo-polymerization proceeded both rapidly and completely with a high double-bond conversion （〉 90%） and a fast curing rate （maximum curing time 〈 21 s） for three monomers. The surface energies of the monomers and the resulting polymer films were then investigated. The minimum surface free energy of the UV-cured homopolymer films reaches 7.1 mJ/m2. X-ray photoelectron spectroscopy data show that the low surthce tension is influenced by fluorine content in the soft segments and fluorinated chains＇ migration to the surface. The five monomers exhibit low viscosity, low surface energy, good thermal stability and good photo-polymerization properties, which make them great candidates for UV coating and photoresist applications.展开更多
The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization(RAFT).The i...The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization(RAFT).The influence of comonomer structure,comonomer feeding ratios,and monomer concentrations on the copolymerization and the copolymer structure have been investigated systematically.With 2-hydroxyethyl vinyl ether(HEVE)and dimethyl maleates(DMM)as comonomers,a well-defined alternating copolymer is prepared with M_(n)=3400 and M_(w)/M_(n)=1.93 up to 71.6% monomer.The alternating sequential chain structure of the copolymers has been proved by both NMR and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS).The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating copolymers.With 2-cyanopropan-2-yl N-methyl-N-(pyridin-4-yl)carbamodithioate as the RAFT agent,the molecular weight of HEVE and DMM copolymer increases with the monomer conversion,demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight distribution.With alternating copolymer of HEVE and DMM as macro-CTA(M_(n)=5200 and M_(w)/M_(n)=1.46),both the chain extension with HEVE and DMM(M_(n)=10400 and M_(w)/M_(n)=1.72)and block copolymerization with vinyl acetate have been successfully achieved(M_(n)=8500 and M_(w)/M_(n)=1.52).展开更多
Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which th...Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which the former acid works as a precursor of the chain transfer agent (CTA) or the dormant species and the latter works as a source of the cationic propagating species. The addition of mixtures of phosphoric acid dibutyl ester ((n=BuO)2PO2H) or 1 -octanethiol (n-C8H17SH) and a trace amount of trifluoromethanesulfonic acid (TfOH) to a solution of isobutyl vinyl ether (IBVE) at -78℃ resulted in polymers with controlled molecular weights, which were basically determined by the feed ratio of IBVE to the weak protonic acid, and narrow molecular weight distributions (Mw/Mn≈ 1.1). These results were almost the same as those obtained using their prepared adducts of IBVE as CT As in the presence of a trace amount of TfOH under similar conditions. Methanesulfonic acid (CH3SO3H), whose adduct of IBVE has not been isolated due to instability, was similarly used in conjunction with trace TfOH to result in controlled molecular weights but slightly broader MWDs (Mw/Mn = 1.2-1.8). These results indicate that the sulfoxonium ion is also an effective intermediate in the cationic DT polymerization in addition to the phosphonium and sulfonium intermediates derived from (n=BuO)2PO2H and C8H17SH, respectively. The simple living cationic polymerization was thus achieved by using a combination of a weak protonic acid and a trace amount of TfOH, which are both easily available, low cost, free from metal, and easy to handle, without need for preparation of the initiator.展开更多
Slightly crosslinked monodisperse poly（maleic anhydride-cyclohexyl vinyl ether-divinylbenzene） （MA-CHVE-DVB） microspheres were prepared via precipitation polymerization while using 2,2- azobisisobutyronitrile as a...Slightly crosslinked monodisperse poly（maleic anhydride-cyclohexyl vinyl ether-divinylbenzene） （MA-CHVE-DVB） microspheres were prepared via precipitation polymerization while using 2,2- azobisisobutyronitrile as an initiator in a mixture of methyl ethyl ketone and n-heptane without any stabilizer. The number-average diameter of the resultant poly（MA-CHVE-DVB） microspheres ranged from 0.478 to 1.386 μm with a polydispersity index of 1.00 to 1.02 that depended on the feed ratios of the MA/CHVE/DVB monomers. The introduction of one electron donor monomer cyclohexyl vinyl ether strongly affected the yield, size, and morphology of these slightly crosslinked microspheres. Quinoline- type chelating resins were obtained after combining the poly（MA-CHVE-DVB） with 8-hydroxyquinoline; the adsorption properties of these materials were measured through their ability to remove Cu^2＋ ions from water. The poly（MA-CHVE-DVB） microspheres with low degrees of crosslinking provided more effective functional groups and therefore better ion removal capabilities. These slightly crosslinked microspheres may have applications in water treatment as well as in sensing and drug delivery.展开更多
The properties of poly(vinyl ether)s(PVEs)are highly dependent on their tacticity,and the appealing thermoplastics features of isotactic PVEs have drawn considerable efforts to develop stereoselective cationic polymer...The properties of poly(vinyl ether)s(PVEs)are highly dependent on their tacticity,and the appealing thermoplastics features of isotactic PVEs have drawn considerable efforts to develop stereoselective cationic polymerization methods to access this class of polymers.However,reported methods that could achieve a high degree of tacticity control are limited to process employing metal-based Lewis acids,and with various limitations on catalyst loading,monomer scope,etc.Here,we introduce a metal-free stereoselective cationic polymerization of vinyl ethers by employing a class of chiral confined Br?nsted acids,imidodiphosphorimidates(IDPis),as the catalyst.This organocatalytic approach features its metal-free conditions,high efficiency,high stereoselectivity,single catalyst system,operation simplicity,etc.展开更多
A novel facile solid-phase organic synthesis of aryl vinyl ethers by reaction of polystyrene-supported 2-phenylsulfonylethanol with phenols under Mitsunobu conditions and subsequent elimination reaction with DBU has b...A novel facile solid-phase organic synthesis of aryl vinyl ethers by reaction of polystyrene-supported 2-phenylsulfonylethanol with phenols under Mitsunobu conditions and subsequent elimination reaction with DBU has been developed. The advantages of this method include straightforward operation, good yield and high purity of the products. Alternatively, a typical example of Suzuki coupling reaction on-resin was further applied to prepare 4-phenylphenyl vinyl ether for extending this method.展开更多
The novel perfluorinated vinyl ether containing sulfonimide and phosphonic acid functionalities, CF2 = CFOCF2CF(CF3)-OCF2CF2SO2NHSO2(CF2)2P(O)(OH)2, has been synthesized by multiple reaction steps. It is a very strong...The novel perfluorinated vinyl ether containing sulfonimide and phosphonic acid functionalities, CF2 = CFOCF2CF(CF3)-OCF2CF2SO2NHSO2(CF2)2P(O)(OH)2, has been synthesized by multiple reaction steps. It is a very strong bi-functional acid and exhibits a high degree of stability in aqueous solution at an elevated temperature. These properties make it an attractive monomer for the preparation of the co-polymer with TFE to obtain the high quality ionomer membrane and proton conductor.展开更多
A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid ...A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by LR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by C-13 NMR The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.展开更多
基金the Korea Ministry of Commerce,Industry,and Energy(Grant RTI04-01-04,Regional Technology Innovation Program).
文摘Polymerization of isobutyl vinyl ether(IBVE)has been studied with mononuclear half-titanocene,CpTiCl_3[1]and dinuclear half-titanocenes,[(C_5H_4)_2(CH_2)_n][(TiCl_3)_2][2(n=3),3(n=6)],and[(C_5H_4)_2(CH_2)_n[(TiCl_2OR_2](R=2,6- diisopropylphenoxyl)[4(n=3),5(n=6)],in the presence of methyl aluminoxanes(MAO)as cocatalyst in methylene chloride.The influences of the length of polymethylene brigde and the substitution of aryloxy group at the metal center have been investigated at three polymerization temperature(...
文摘The interconversion between the two distinct isomers of methyl vinyl ether （MVE）, the formation of the primary ozonides from O3-initated reactions of MVE, the transformation between the primary ozonides, and the subsequent fragmentation were studied using quantum chemical methods at the BHandHLYP/6311＋＋G（d,p） level of theory for optimized geometries and frequency calculations and at the QCISD/631G（d,p） level for the single point energy calculations. The rate coefficients were calculated for the temperature range 280-440 K by using the canonical transition state theory （TST）. For ozone addition to MVE, there are two different possibilities discussed on the basis of two different possible orientations for ozone attack. The results of the theoretical study indicate that although the synperiplanar-MVE is 7.11 kJ/mol more stable than the antiperiplanar-MVE, the antiperiplanar-MVE plays a more important role in formation of the primary ozonides because the primary ozonides formed from the ozone addition antiperiplanar-MVE are more stable and the energy barriers corresponding to transition states are lower. The intereonversion between the primary ozonides formed from the ozone addition to antiperiplanar-MVE is the most accessible compared with the transformations between other primary ozonides. The cleavage of the primary ozonides mainly leads to the formation of the CH2OO, which is in agreement with the experimental estimates. The calculated overall rate constant for the ozone-initiated reactions is 4.8× 10^-17 cm^3/（molecule.s） at 298.15 K, which agrees with the experimental value for ethyl vinyl ether.
基金the Natural Science Foundation of Zhejiang Province(No.LY13B020015)Zhejiang Key Innovation Team of Green Pharmaceutical Technology(No.2012R10043-07) for financial support
文摘An efficient and regioselective synthesis of N-9 alkoxyalkylated purine nucleoside derivatives was achieved via the N-alkoxyalkylation of purine rings with vinyl ethers catalyzed by L-ProT.The advantages of this protocol include good to excellent yield,mild reaction condition,and simple manipulation.A plausible mechanism for the transformation was given.
基金the Natural Science Foundation of Jiangxi Province(No.0420017)for financial support
文摘A mild, one-pot procedure for the synthesis of vinyl ethers in good yields from 2-hydroxyalkyl phenyl selenides with primary or secondary organic halides has been developed.
基金financially supported by the Beijing Municipal Natural Science Foundation(No.2112020)
文摘Five fluorine-containing vinyl ether monomers were prepared by the reaction between 2-vinyloxy ethanol, a fluorinated alcohol and hexafluorobenzene in the presence of sodium hydride in dimethylformamide. Two representative properties of these monomers, UV-curing behavior initiated by a cationic photo-initiator PAG 201 and surface free energy of coating films, were investigated. Photo-polymerization proceeded both rapidly and completely with a high double-bond conversion （〉 90%） and a fast curing rate （maximum curing time 〈 21 s） for three monomers. The surface energies of the monomers and the resulting polymer films were then investigated. The minimum surface free energy of the UV-cured homopolymer films reaches 7.1 mJ/m2. X-ray photoelectron spectroscopy data show that the low surthce tension is influenced by fluorine content in the soft segments and fluorinated chains＇ migration to the surface. The five monomers exhibit low viscosity, low surface energy, good thermal stability and good photo-polymerization properties, which make them great candidates for UV coating and photoresist applications.
基金financially supported by the National Natural Science Foundation of China(No.22171017).
文摘The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization(RAFT).The influence of comonomer structure,comonomer feeding ratios,and monomer concentrations on the copolymerization and the copolymer structure have been investigated systematically.With 2-hydroxyethyl vinyl ether(HEVE)and dimethyl maleates(DMM)as comonomers,a well-defined alternating copolymer is prepared with M_(n)=3400 and M_(w)/M_(n)=1.93 up to 71.6% monomer.The alternating sequential chain structure of the copolymers has been proved by both NMR and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS).The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating copolymers.With 2-cyanopropan-2-yl N-methyl-N-(pyridin-4-yl)carbamodithioate as the RAFT agent,the molecular weight of HEVE and DMM copolymer increases with the monomer conversion,demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight distribution.With alternating copolymer of HEVE and DMM as macro-CTA(M_(n)=5200 and M_(w)/M_(n)=1.46),both the chain extension with HEVE and DMM(M_(n)=10400 and M_(w)/M_(n)=1.72)and block copolymerization with vinyl acetate have been successfully achieved(M_(n)=8500 and M_(w)/M_(n)=1.52).
基金supported in part by a JSPS KAKENHI Grant-inAid for Early-Career Scientists (No. JP18K14274) for M.U
文摘Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which the former acid works as a precursor of the chain transfer agent (CTA) or the dormant species and the latter works as a source of the cationic propagating species. The addition of mixtures of phosphoric acid dibutyl ester ((n=BuO)2PO2H) or 1 -octanethiol (n-C8H17SH) and a trace amount of trifluoromethanesulfonic acid (TfOH) to a solution of isobutyl vinyl ether (IBVE) at -78℃ resulted in polymers with controlled molecular weights, which were basically determined by the feed ratio of IBVE to the weak protonic acid, and narrow molecular weight distributions (Mw/Mn≈ 1.1). These results were almost the same as those obtained using their prepared adducts of IBVE as CT As in the presence of a trace amount of TfOH under similar conditions. Methanesulfonic acid (CH3SO3H), whose adduct of IBVE has not been isolated due to instability, was similarly used in conjunction with trace TfOH to result in controlled molecular weights but slightly broader MWDs (Mw/Mn = 1.2-1.8). These results indicate that the sulfoxonium ion is also an effective intermediate in the cationic DT polymerization in addition to the phosphonium and sulfonium intermediates derived from (n=BuO)2PO2H and C8H17SH, respectively. The simple living cationic polymerization was thus achieved by using a combination of a weak protonic acid and a trace amount of TfOH, which are both easily available, low cost, free from metal, and easy to handle, without need for preparation of the initiator.
基金The financial supports from the National Science Foundation of China(Grant No.20774037 and 21304037)Shandong Excellent Young Scientist Research Award Fund(No.BS2013CL039)
文摘Slightly crosslinked monodisperse poly（maleic anhydride-cyclohexyl vinyl ether-divinylbenzene） （MA-CHVE-DVB） microspheres were prepared via precipitation polymerization while using 2,2- azobisisobutyronitrile as an initiator in a mixture of methyl ethyl ketone and n-heptane without any stabilizer. The number-average diameter of the resultant poly（MA-CHVE-DVB） microspheres ranged from 0.478 to 1.386 μm with a polydispersity index of 1.00 to 1.02 that depended on the feed ratios of the MA/CHVE/DVB monomers. The introduction of one electron donor monomer cyclohexyl vinyl ether strongly affected the yield, size, and morphology of these slightly crosslinked microspheres. Quinoline- type chelating resins were obtained after combining the poly（MA-CHVE-DVB） with 8-hydroxyquinoline; the adsorption properties of these materials were measured through their ability to remove Cu^2＋ ions from water. The poly（MA-CHVE-DVB） microspheres with low degrees of crosslinking provided more effective functional groups and therefore better ion removal capabilities. These slightly crosslinked microspheres may have applications in water treatment as well as in sensing and drug delivery.
基金supported by the Recruitment Program of Global Experts,Beijing National Laboratory for Molecular Sciences(BNLMS201913)Fuzhou University。
文摘The properties of poly(vinyl ether)s(PVEs)are highly dependent on their tacticity,and the appealing thermoplastics features of isotactic PVEs have drawn considerable efforts to develop stereoselective cationic polymerization methods to access this class of polymers.However,reported methods that could achieve a high degree of tacticity control are limited to process employing metal-based Lewis acids,and with various limitations on catalyst loading,monomer scope,etc.Here,we introduce a metal-free stereoselective cationic polymerization of vinyl ethers by employing a class of chiral confined Br?nsted acids,imidodiphosphorimidates(IDPis),as the catalyst.This organocatalytic approach features its metal-free conditions,high efficiency,high stereoselectivity,single catalyst system,operation simplicity,etc.
基金Acknowledgement This work was supported by the National Natural Science Foundation of China （No. 21062007） and the Research Program of Jiangxi Province Department of Education （No. GJJ10385, GJJ11380）.
文摘A novel facile solid-phase organic synthesis of aryl vinyl ethers by reaction of polystyrene-supported 2-phenylsulfonylethanol with phenols under Mitsunobu conditions and subsequent elimination reaction with DBU has been developed. The advantages of this method include straightforward operation, good yield and high purity of the products. Alternatively, a typical example of Suzuki coupling reaction on-resin was further applied to prepare 4-phenylphenyl vinyl ether for extending this method.
文摘The novel perfluorinated vinyl ether containing sulfonimide and phosphonic acid functionalities, CF2 = CFOCF2CF(CF3)-OCF2CF2SO2NHSO2(CF2)2P(O)(OH)2, has been synthesized by multiple reaction steps. It is a very strong bi-functional acid and exhibits a high degree of stability in aqueous solution at an elevated temperature. These properties make it an attractive monomer for the preparation of the co-polymer with TFE to obtain the high quality ionomer membrane and proton conductor.
文摘A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by LR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by C-13 NMR The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.
