Synthesis and Characterization of (+)-α-Phenylethanammonium Phosphotungstate and Its Catalytic Performance for Asymmetric Epoxidation

以Keggin型12-磷钨酸和(+)-α-苯乙胺为原料,通过水热法合成了具有Keggin结构的(+)-α-苯乙胺磷钨酸盐(C8H12-N)3PW12O40.通过红外光谱、核磁共振波谱、紫外光谱、元素分析和热重分析等技术对合成产物进行了结构、组成和热稳定性的表征和考察,证实了合成产物为(+)-α-苯乙胺磷钨酸盐.以顺丙烯磷酸-α-苯乙胺盐环氧化合成(1R,2S)-环氧丙基磷酸-α-苯乙胺盐为探针反应,考察了(C8H12N)3PW12O40催化不对称环氧化性能.结果表明,在催化剂用量为2.00%和反应温度为50℃时,产物环氧丙基磷酸苯乙胺盐的收率为64%,(1R,2S)-环氧丙基磷酸苯乙胺盐的对映选择性ee值为10.8%.A(+)-α-phenylethanammonium phosphotungstate(C8H12N)3PW12O40 was synthesized by a mild hydrothermal technique and its structure was characterized by infrared spectroscopy,nuclear magnetic resonance,ultraviolet spectroscopy,elemental analysis,and thermogravimetry.A probe reaction of the epoxidation of(±)-α-phenylethanammonium-cis-1-propenylphosphonate into α-phenylethanammonium-cis-1,2-epoxypropyl phosphonate was carried out to investigate the catalytic performance of(C8H12N)3P-W12O40.A yield of 64% of epoxide and ee of 10.8% of α-phenylethanammonium-cis-(1R,2S)-epoxypropyl phosphonate were obtained with 2% catalyst at temperature 50 ℃.河南省杰出人才创新基金(0221001200

Synthesis and Characterization of (+)-alpha-Phenylethanammonium Phosphotungstate and Its Catalytic Performance for Asymmetric Epoxidation

A ( + )-alpha-phenylethanammonium phosphotungstate (C8H12N)(3)PW12O40 was synthesized by a mild hydrothermal technique and its structure was characterized by infrared spectroscopy, nuclear magnetic resonance, ultraviolet spectroscopy, elemental analysis, and thermogravimetry. A probe reaction of the epoxidation of ( +/- ) -alpha-phenylethanammonium-cis-1-propenylphosphonate into alpha-phenylethanammoniuni- cis -1, 2-cpoxypropyl phosphonate was carried out to investigate the catalytic performance of (C8H12N)(3)PW12O40. A yield of 64% of epoxide and ee of 10.8% of alpha-phenylethanammonium-cis-(1R, 2S)-epoxypropyl phosphonate were obtained with 2% catalyst at temperature 50 degrees C

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我们于1983年至1984年间在武汉东湖进行网箱放养中国圆田螺的试验;得出以下结论： (1)中国圆田螺在武汉地区的生殖季节自3月中旬至11月底;其中以5—6月份产螺达高峰; (2)雌螺长至壳高36—37毫米时开始繁殖子代。(3)在自然种群中;中国圆田螺每雌每年平均产螺达50—60个．(4)初生仔螺(壳高7毫米)死亡率最大;高达50％以上。(5)刚出生的中国圆田螺雌体;经过几个月正常生长;当年开始或至次年开春部可繁殖后代

中国高等植物受威胁物种名录

2008年,环境保护部和中国科学院联合启动了《中国生物多样性红色名录——高等植物卷》的编制工作。通过这项工作,我们依据IUCN濒危物种红色名录标准对中国野生高等植物的濒危状况进行了全面评估,编制了中国高等植物红色名录。2013年9月,该名录以环境保护部、中国科学院第54号公告形式发布,即《中国生物多样性红色名录—

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies