CaO as a Solid Base Catalyst for Transesterification of Soybean Oil

用不同的前驱物合成了三种CaO催化剂,并以X射线衍射(XRD)、扫描电子显微镜(SEM)、程序升温脱附(TPD)等方法加以表征.这些CaO被用作大豆油(SBO)经酯交换制取脂肪酸甲酯(FAME),即生物柴油的催化剂,由方解石制备的氧化钙(Cal(N))表现了最好的SBO酯交换活性.检测发现CaO的酯交换活性与它们的碱性强度密切相关,当暴露于CO2气氛下,显著降低了CaO的酯交换催化活性(Raman光谱测试显示当置CaO于常温空气中,其表面形成的CaCO3和Ca(OH)2将阻止CaO继续参与SBO的酯交换反应).CO2的毒化颇受制于CaO前驱体种类,Cal(N)比来自文石的CaO(即Ara(N))有更好的抗CO2毒化能力;这些受损的CaO催化活性可部分复原.提出了CaO催化剂受CO2毒化及其再生的机理,同时讨论了SBO酯交换活性相到底是CaO固体表面,拟或溶解了的CaO的问题.Three different calcium oxide catalysts were synthesized from different precursors and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and temperature-programmed desorption (TPD). They were used as catalysts in the transesterification of soybean oil (SBO) for the production of fatty acid methyl esters (FAME), namely biodiesel. Calcium oxide from calcite (Cal(N)) showed the highest activity towards the transesterification of SBO. The transesterification activity of CaO was found to be highly related to the basicity of the catalysts. The catalytic activity of CaO greatly decreased when CaO was exposed to CO2. (Raman spectroscopic studies demonstrated that the formation of CaCO3 and Ca(OH)2 on the surface of CaO when CaO was exposed to room air prevented CaO from participating in the transesterification of SBO). The degree of poisoning was highly dependent on the type of precursors with Cal(N) more resistant to CO2 poisoning than CaO from aragonite (Ara(N)). Deactivated CaO catalysts could be partially regenerated. A mechanism was proposed to explain the poisoning and regenerating processes. Furthermore, whether the solid phase of CaO or dissolved CaO was the active species in the transesterification of SBO was also investigated.教育部生物质能源重大项目(教技司(2007)29号文);; 固体表面物理化学国家重点实验室资

CaO as a Solid Base Catalyst for Transesterification of Soybean Oil

Three different calcium Oxide catalysts were synthesized from different precursors and characterized by Xray diffraction (XRD), scanning electron microscopy (SEM), and ternperature-programmed desorption (TPD). They were used as catalysts in the transesterification of soybean oil (SBO) for the production of fatty acid methyl esters (FAME), namely biodiesel. Calcium oxide front calcite (Cal(N)) showed the highest activity towards the transesterification of SBO. The transesterification activity of CaO was found to be highly related to the basicity of the catalysts. The catalytic activity of CaO greatly decreased when CaO was exposed to CO, (Raman spectroscopic Studies demonstrated that the formation of CaCO3 and Ca(OH)(2) oil the surface of CaO when CaO was exposed to room air prevented CaO from participating in the transesterification of SBO). The degree of poisoning was highly dependent on the type of precursors with Cal(N) more resistant to CO., poisoning than CaO from aragonite (Ara(N)). Deactivated CaO catalysts could he partially regenerated. A mechanism was proposed to explain the poisoning and regenerating processes. Furthermore, whether the solid phase of CaO or dissolved CaO wits the active species in the transesterification of SBO was also investigated

Syntheses and crystal structures of two novel zinc(II) coordination polymers

Two novel zinc(ii) coordination polymers, [Zn-3(mu(3)-OH)(2)(nip)(2)] (1) and [Zn-2(nip)(2)(4,4'-bpy)(3).(OH2)] (2) (H(2)nip = 5-nitroisophthalic acid, 4,4'-bpy = 4,4'-bipyridyl), were obtained by the hydrothermal reactions of zinc nitrate, 5-nitroisophthalate (nip) (for 1) and zinc nitrate, 5-nitroisophthalate and 4,4'-bipyridyl (for 2). Complex 1 displays a two-dimensional structure that is built from [Zn-3(mu(3)-OH)(2)](n) chains, while complex 2 is a three-dimensional structure formed by the interpenetration of two-dimensional hydrogen-bonded bilayers. The photoluminescent properties of complex 1 have also been investigated. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003

大连极紫外相干光源

先进光源的发展在前沿科学研究中发挥的作用越来越重要。近十年来,飞速发展的自由电子激光技术为科学家们提供了探索未知世界、发现新科学规律和实现技术变革的重要工具。建成的大连极紫外(EUV)相干光源的运行波段为50~150nm,单脉冲能量大于100μJ,且可提供10-12 s和10-13 s量级的超快激光脉冲,是我国第一台自由电子激光用户装置,并且是国际上唯一运行在极紫外波段的自由电子激光用户装置,在世界范围内为用户提供具有高峰值亮度和超短脉冲的极紫外激光。大连EUV相干光源是由国家自然科学基金委资助、由中国科学院大连化学物理研究所和上海应用物理研究所共同承担的重大科学仪器研制项目,目标是打造一个以先进极紫外光源为核心、主要用于能源基础科学研究的光子科学平台

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