共查询到17条相似文献,搜索用时 109 毫秒
1.
2.
3.
从α-蒎烯直接催化酯化高选择性地合成乙酸正龙脑酯的研究-催化剂与反应机理初探 总被引:1,自引:0,他引:1
本文提出了新的硼酸类催化剂体系HB,用该体系对α-蒎烯与无水乙酸相互作用直接合成乙酸正龙脑酯作了较系统的研究。反应得到两种系列产物-酯化产物和异构化产物,酯化产物主要是乙酸正龙脑酯,葑醇酯和松油酯,异构化产物主要是莰烯、烯和松油烯等,总酯化产率为50%以上,其中乙酸正龙脑酯为20%以上,是至今从α-蒎烯直接合成乙酸正龙脑酯的最好结果。通过对产物的 ̄1HNMK图谱分析及动力学考察,确证反应主产物是正龙脑酯而不是异龙脑酯。文章对H_2SO_4、HClO_4、多聚磷酸(PPA)和杂多酸(12-磷钨酸)等催化剂进行了实验考察、对比和评述,表明了自制的HB催化剂体系具有高选择性合成乙酸正龙脑酯的显著优点,并对其反应机理作了初步探讨。 相似文献
4.
5.
6.
冰片中右旋龙脑及其异构体的手性毛细管气相色谱法测定 总被引:6,自引:0,他引:6
以CYDEX -B手性毛细管柱 (25m×0.22mm,0.25μm)作为分析柱,用气相色谱法和气相色谱 -质谱联用法对天然冰片、艾片和合成冰片进行测定。合成冰片中的左旋龙脑与右旋龙脑可完全分离 ,左旋异龙脑与右旋异龙脑可部分分离。实验测得 :天然冰片中右旋龙脑的含量为99.13%~99.61 %;艾片中左旋龙脑的含量为95.87 %;合成冰片中左旋龙脑的含量为31.44 %~54.57 %,右旋龙脑的含量6.87 %~25.37 %;合成冰片的比旋度 α30D 为 -17.3°~ -2.3°。 相似文献
7.
8.
9.
10.
11.
《国际化学动力学杂志》2018,50(6):383-396
Polyethylene glycols (PEG) acts as efficient catalysts for the oxidation of bicyclic monoterpenes such as borneol, isoborneol, and camphor by ceric ammonium nitrate (CAN), a laboratory desktop reagent, in acetonitrile medium under mineral acid‐free conditions. The kinetics of the reactions revealed first‐order dependence on in both [CAN] and [bicyclic terpene]. The rate of oxidation is accelerated with an increase in [PEG] linearly, which could be explained by considering PEG‐bound oxidant (PEG‐CAN) as more reactive species than (CAN) itself. The mechanism of oxidation in PEG media has been explained through the participation of PEG‐bound oxidant (PEG‐CAN) and bicyclic monoterpene in the slow step. 相似文献
12.
R. Robbiani H. Bührer H. Mndli D. Kova
evi A. Fraefel J. Seibl 《Journal of mass spectrometry : JMS》1978,13(5):275-279
Results of an investigation of deuterium labelled methylated norborneols and dihydrocarveols are presented to show that the 1,2 elimination of water in borneol and isoborneol is triggered by an initial ring cleavage reaction. Other eliminations of water in borneol and isoborneol are elucidated by specific and stereospecific deuterium labelling in different positions. 相似文献
13.
14.
15.
I. Yu. Chukicheva I. V. Fedorova V. A. Yagolˈnitskaya A. V. Kuchin 《Chemistry of Natural Compounds》2011,47(1):51-54
Phenol was alkylated by borneol and its stereoisomer isoborneol in the presence of aluminum phenolate and isopropylate. The
reaction products were isolated and characterized. Certain features of the process were defined. 相似文献
16.
This study describes the reactions of natural chiral alcohols such as borneol, isoborneol, cholesterol, and dihydrocholesterol with 3-phenyl-1,2,4-triazin-5(4H)-one in the presence of carboxylic acid anhydrides. 相似文献
17.
蒙古蒿精油化学成份的研究I. 总被引:1,自引:0,他引:1
The chemical constituents of the essential oil from the leaves of artemisia mongolica Fisch. were separated by gas chromatography employing glass capillary eolumns and identified by GC-MS-COM. 30 components have been separated and identified, i.e. 2-methyl-2-butene, methylene cyclopentane, 7,7-dimethyl-3-methylen-bicyclo-(3, 1, 1) heptane, α-thujene, α-pinene, camphene, 1-octen-3-o1, β-thujene, β-pinene, α-phellandrene, bornylene, p-cymene, terpinen-1-o1, artemisia ketone, γ-terpinene, β-terpineol, 3,7,7-trimethyl-bicyclo-(3, 1,1)-2-heptanol, α-terpinolene, verbenone, linalool iso-thujone, thujone, camphor, isopulegone, isoborneol, terpinen-4-o1, α-terpineol, myrtenol, trans- carveol, cis-carveol. 相似文献