排序方式: 共有24条查询结果,搜索用时 39 毫秒
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Hélène Pellissier Author Vitae 《Tetrahedron》2006,62(24):5559-5601
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通过溶胶凝胶法制备了手性向列型介孔二氧化硅(CNMS)和用浸渍法制备了磺酸化手性向列型介孔硅(CNMS-SO3H)固体酸催化剂。 通过比表面积分析(BET)、X射线衍射仪(XRD)、红外吸收光谱分析法(FT-IR)、氨-程序升温脱附(NH3-TPD)和吡啶吸附红外光谱(Py-FTIR)等技术手段表征催化剂的结构和性质。 结果表明,在α-蒎烯与无水草酸物质的量比为1∶0.4,CNMS-SO3H催化剂用量与松节油的质量比为7∶100。 温度为100 ℃,时间为8 h,龙脑的收率最高为49.89%,α-蒎烯转化率为100%,正龙脑的量是异龙脑的4倍。 固体酸催化剂具有很好的催化活性和稳定性,在重复使用8次之后,α-蒎烯转化率在99%以上。 相似文献
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The constituents of Saudi Lavandula dentata oil were identified by two GLC-Mass spectrophotometric systems. Camphor, fechone, fenchyl alcohol and borneol were the major components of the oil. Other components were also identified. 相似文献
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介绍了一个适用于本科教学的仪器分析实验--气相色谱法测定野菊花中樟脑和龙脑的含量。实验从笔者的科研成果转化而来,并在教学过程中逐年优化,展示了一个实际样品的完整分析流程。首先采用水蒸馏同时溶剂萃取法提取野菊花中的挥发油,然后利用毛细管气相色谱法对挥发油中的樟脑和龙脑进行定性和定量。在掌握样品的前处理方法、内标标准曲线法及气相色谱仪的原理和使用的基础上,通过鼓励学生分组讨论影响实验结果的主要因素,自主选择合理的实验条件对实验方法进行优化和改进,激发学生的科研热情和创新思维,培养学生分析和解决实际问题的能力。 相似文献
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Dayong Zheng Yang Chu Shuming Li Shuiping Zhou Wei Li Yuesheng Xie He Sun 《Biomedical chromatography : BMC》2022,36(5):e5311
Borneol (Bingpian), a monoterpenoid pharmaceutical ingredient, is commonly used as a main composition in traditional Chinese medicine preparations such as compound Danshen dropping pills (CDDP) and has also been approved by the U.S. Food and Drug Administration as a flavoring substance or adjuvant in food. Borneol plays a regulating and guiding role as a messenger drug in CDDP. However, the effect of borneol on the pharmacokinetics of the components of CDDP in human plasma is unclear. In this study, we investigate the effects of borneol on the pharmacokinetics of ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1), and notoginsenoside R1 (NR1) in CDDP. We used a double-cycle crossover-administration model in 12 healthy male volunteers, administered CDDP with borneol (drug T) and without borneol (drug R). The selective response monitoring mode was used for MS quantification in the positive mode. As a result, we found that borneol could significantly affect the pharmacokinetic parameters of notoginsenosides and increase the absorption and systemic exposure of Rb1, Rg1, and NR1 in human plasma by ~1.85–3.71 times. 相似文献