共查询到20条相似文献,搜索用时 281 毫秒
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以丹皮酚和2,4-二羟基苯乙酮为研究对象,采用Q Exactive四极杆-静电场轨道阱高分辨质谱系统,及内置有Ⅰ相和Ⅱ相代谢途径分析的MetWorks代谢物鉴定软件,系统分析丹皮酚经肝微粒体代谢的Ⅰ相代谢及其Ⅰ相代谢产物2,4-二羟基苯乙酮经微粒体代谢的Ⅱ相代谢产物。结果表明,丹皮酚在大鼠肝微粒体中经Ⅰ相代谢后产物主要为4位去甲基化的2,4-二羟基苯乙酮和1位相邻羰基的脱甲基化的2-羟基-4-甲氧基苯甲醛以及5位的羟基化代谢产物2,5-二羟基-4-甲氧基苯乙酮,而2,4-二羟基苯乙酮的Ⅱ相代谢产物主要为4位葡萄糖醛酸化的糖苷化代谢产物2-羟基-4’-O-葡萄糖醛酸苯乙酮。 相似文献
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T. Takei K. Kato A. Meguro M. Chikazawa 《Colloids and surfaces. A, Physicochemical and engineering aspects》1999,150(1-3):77-84
We investigated the O---H stretching frequencies of geminal and triple hydroxyl groups on silica surface by FT-IR spectroscopy. The geminal and triple hydroxyl groups were individually prepared by the chemical reaction of alkylchlorosilane with surface isolated hydroxyl groups which are separated enough and following hydroxylation of surface chlorine groups. The O---H stretching frequencies of these generated geminal and triple hydroxyl groups were observed at frequencies by 2 and 3 cm−1 lower than that of isolated ones, respectively. By heat treatment the triple hydroxyl groups are firstly eliminated, and secondly the geminal hydroxyl groups disappear. Lastly only isolated hydroxyl groups remain on silica surface. 相似文献
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对MgO重新水合及两类羟基的研究 总被引:2,自引:1,他引:1
蔡炳新 《高等学校化学学报》1994,15(11):1690-1693
采用IR、XRD、TG-DTA等手段对MgO重新水合及其两类羟基进行了研究。发现MgO水解后活性增大,在实验条件下水解仅发生在表面浅层;水合可得到自由、水合两类羟基,600℃灼烧使两类羟基脱除;自由羟基由水合羟基在碱[O2-]作用下生成;添加Li+对表面两类羟基有影响。 相似文献
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The variation of the fundamental hydroxyl stretching frequency in the infrared spectrum of a number of epoxy–diamine networks has been determined as a function of temperature. Short-range hydrogen bonds appear to be formed in all the epoxy networks examined. For polymers formed by using short-chain α,ω-diamines, it appears that a hydroxyl–hydroxyl bond is dominant. For longer chain lenghts, a hydroxylamine bond becomes important. The hydroxyl–hydroxyl bond breaks at the glass transition temperature, whereas the hydroxyl–amine bond breaks at a higher temperature. At the highest temperatures studied, all hydroxyl groups form weak short-range bonds to the alkyl-aryl ether function. The absorption frequency for the hydroxyl group in all types of hydrogen bonds formed shows a strong dependence on temperature and absorption moves to a higher wavenumber with increase in temperature. 相似文献
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最小二乘—红外光谱法定量测定羟基化合物 总被引:2,自引:0,他引:2
根据羟基伸缩振动吸收带的特性,用最小二乘法有效消除了溶液中羟基间的缔合作用对测定结果的影响。此方法已用于聚合物中羟基含量的测定。 相似文献
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用FT-IR和NH_2-TPD研究了稀土含量相同时脱铝程度不同的四种REUSY沸石的酸性质. 并对复杂羟基谱的归属进行了讨论. 同时将酸性质与骨架的Si、Al分布, 非骨架组份以及二次孔相关联, 提出浅、中度脱铝时主要脱除与超笼中HFOH相关联的Si(3Al)和Si(2Al)单元中的Al, 深度脱铝时则脱除与六方柱笼和方钠石笼中LFOH 羟基相关联的Si(1AI)中的铝和少量Si(2Al)中的铝. 另外发现, 非骨架组份使一部分HFOH羟基不能被吡啶分子接近. 而二次孔的形成使一部份LFOH 能被吡啶分子接近. 随着脱铝深度的加深, 总酸、B酸、L 酸量都减少. 但强酸和B酸的强度均相应增加. 相似文献
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明日叶黄酮类化合物清除羟基自由基活性研究 总被引:1,自引:0,他引:1
为了研究明日叶黄酮类化合物对羟基自由基的清除作用,以明日叶(主要取叶片)为原料,用体积分数为65%乙醇提取明日叶总黄酮,测定其总黄酮含量.通过Fenton反应体系产生羟基自由基,利用明日叶提取液中的功能成分黄酮类化合物对羟基自由基的清除作用进行研究.结果表明:明日叶提取物总黄酮质量分数为10.18%,且黄酮类化合物对羟基自由基有较强清除效力,当提取物总黄酮浓度在0.1~1.0 mg/mL范围内,其与清除率呈正相关.明日叶中黄酮类化合物对羟基自由基有较强清除效力,作为天然抗氧化产品开发具有一定价值. 相似文献
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The stretching mode of hydroxyl ions (OH? and OD?), which are located at the Ag electrode-electrolyte interface, has been observed. Two distinct peaks in the surface enhanced Raman spectra of interfacial hydroxyl ions were observed. The assignment of Raman peaks to hydroxyl ions was confirmed by adding KOH or HCl to the electrolyte or by electrochemically generating hydroxyl ions and hydrogen gas at the electrode interface. 相似文献