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1.
比较了AlCl_3和AlCl_3/SbCl_3复合体系的α-蒎烯/苯乙烯阳离子共聚反应及产物的摩尔质量分布。结果表明,由于用AlCl_3体系两种单体活性差大而难以共聚,用AlCl_3/SbCl_3复合体系,苯乙烯聚合速率相对减小,而α-蒎烯聚合速率增大,加之苯乙烯的共催化剂作用,加速α-蒎烯聚合,可使α-蒎烯与苯乙烯进行有效共聚。考察了[Sb]/[Al]比、催化剂浓度、单体投料比等对共聚体系α-蒎烯、苯乙烯转化速率及产物M_n的影响。  相似文献   

2.
AlCl3/SbCl3复合体系引发α—蒎烯/苯乙烯阳离子共聚合   总被引:6,自引:0,他引:6  
卢江  梁晖 《应用化学》1996,13(1):10-13
比较了AlCl3和AlCl3/SbCl3复合体系的α蒎烯/苯乙烯阳离子共聚反应及产物的摩尔质量分布。结果表明,由于用AlCl3体系两种单体活性差大而难以共聚,用AlCl3/SbCl3复合体系,苯乙烯聚合速率相对减小,而α蒎烯聚合速率增大,加之苯乙烯的共催化剂作用,加速α-蒎烯聚合,可使α-蒎烯与苯乙烯进行有效共聚,考察(Sb)/(Al)比,催化剂浓度,单体投料比等对共聚体系α蒎烯,苯乙烯转化速率及  相似文献   

3.
复合催化剂AlCl3/SbCl3的α—蒎烯/苯乙烯阳离子聚合反…   总被引:5,自引:0,他引:5  
用微臭氧化-薄层层析法分析测定了复合催化剂AlCl3/SbCl3在不同Sb比、投料比、溶剂和温度等条件下的α-蒎烯(M1)/苯乙烯(M2)共聚产物的构成。表明该复合催化剂可获得 ̄100%共聚体,其中α-蒎烯链节含量F1可在30% ̄56%之间调控。在仅生成共聚体的条件下由Mayo-Lewis积分式首次测定了竞聚率。AlCl3/SbCl3和单独AlCl3相比,r1增大,r2减小,r2/r1值降低了5 ̄  相似文献   

4.
气相色谱-质谱法测定姜黄挥发油化学成分   总被引:4,自引:2,他引:2  
胡永狮  杜青云  汤秋华 《色谱》1998,16(6):528-529
采用水蒸气蒸馏法提取姜黄挥发油,用气相色谱-质谱联用技术分离和鉴定姜黄挥发油的化学成分。经计算机NBS谱库检索,发现姜黄挥发油中至少有15个峰,鉴定出α-姜黄烯、α-姜烯、桉叶油素和球姜酮等15种组分;另外还有1-(3-环戊基醛)-2,4-二甲基苯、β-倍半水芹烯、大根香叶酮、大根香叶烷、顺双环[3,3,1]酮-2-烯-9-醇等成分。姜黄挥发油中主要成分为α-姜黄烯。  相似文献   

5.
卢江  梁晖 《高分子学报》1998,(6):698-703
比较了萜烯单体α-蒎烯、β-蒎烯、苎烯的阳离子聚合性能,还考察了三种单体的活性聚合可能性。在Lewis酸AlCl3作用下,聚合速率大小顺序为:β-蒎烯的聚合产物分子量较高。AlCl3与SbCl3复合后,α-蒎烯、苎烯的聚合速率增加,β-蒎烯的聚合速率反而下降。α-蒎烯的聚合速率增加幅度大于苎烯,使得前者聚合速率高于后者。与使用AlCl3相比,添加SbCl3后产物的分子量变化是:α-蒎烯变大,苎烯不  相似文献   

6.
根据假设建立了复合引发体系SbCl3/AlCl3/D(给电子体)的α-蒎烯聚合动力学模型。研究结果表明,该模型符合该聚合反应实际,可操作性强。用计算机拟合通过该模型首次获得了研究条件下α-蒎烯聚合的链增长速率kp和链终止速率kt值以及聚合活化能。  相似文献   

7.
用微臭氧化-薄层层析法分析测定了复合催化剂AlCl_3/SbCl_3,在不同Sb/Al比、投料比、溶剂和温度等条件下的α-菠烯(M_1)/苯乙烯(M_2)共聚产物的构成,表明该复合催化剂可获得~100%共聚体,其中α-蒎烯链节含量F1可在30%~56%之间调控。在仅生成共聚体的条件下由Mayo-Lewis积分式首次测定了竞聚率。AlCl_3/SbCl_3和单独AlCl_3相比,r1增大,r2减小,r2/r1值降低了5~6倍,使不易共聚的M_1/M_2变为易于共聚,可制备M_1组分含量高的共聚体。确认该复合催化剂对M_1/M_2的优良共聚合性能在于阳离子聚合活性种的非质子和抗衡阴离子(团)的特殊结构和性质.  相似文献   

8.
α—蒎烯阳离子聚合的二聚体研究   总被引:1,自引:0,他引:1  
研究了α-蒎烯阳离子聚合反应中二聚体的形成及其结构。结果表明,活性中心为H^+的AlCl3,CF3SO3H催化体系引发α-蒎烯聚合,产物中二聚体含量较高(27 ̄63%);而在引发活性中心为金属正离子的AlCl3/SbCl3复合体系的产物中,二聚体含量很低( ̄5%)。用制备GPC对二聚不同进行分离,进而用^13C-NMR、^1H-NMR进行结构分析,提出了5种主要二聚体的分子结构。不同催化体系导致相  相似文献   

9.
云南怒江地区芒果香味的分析   总被引:6,自引:0,他引:6  
李庆春  邱玲  熊杰 《色谱》1998,16(3):268-270
用GC/MS方法分析测定了采自云南怒江农场的芒果属(MangiferaL)的3个品种三年芒、吕宋芒和马切苏芒的主要香味物质。每个品种的香味成分均在20个以上。对主要成分进行了半定量计算,结果表明三年芒主要含有异松油烯、γ-羟辛酸内酯、3,7-二甲基-1,3,6-辛三烯、γ-羟己酸内酯、石竹烯、2,6-二叔丁基-4-甲基苯酚;吕宋芒主要含α-蒎烯、蒈烯、2,6-二叔丁基-4-甲基苯酚、石竹烯、γ-羟己酸内酯。  相似文献   

10.
本文用ESR谱和XPS谱对这类催化剂作了表征研究。结果表明,在经Al ̄(3+)掺杂的ZnO-Al_2O_3体系上,观测到g=1.9606±0.0002,△H_(pp)=(2.8±0.1)×10 ̄(-4)T的顺磁信号,该信号强度(以自旋数/克表示)随ZnO中Al_2O_3掺杂量增加而增长;当Al/Zn达2/100(原子比)时,逐渐趋于平稳。相关体系的ESR和XAES比较研究结果排除了该顺磁信号系产生于顺磁氧物种(诸如,O_2-、O-或O_3-)或Zn+的可能性,而有利于关于三价金属离子(AL ̄(3+))掺杂在ZnO晶格中诱导生成正一价缺位的推断。这类Shottky缺位在催化剂表面富集,有利于表面Cu ̄+物种的稳定,从而促进了CO加氢活性的提高。  相似文献   

11.
The aims of this study were to test the antifungal activity, toxicity and chemical composition of essential oil from C. sativum L. fruits. The essential oil, obtained by hydro-distillation, was analyzed by gas chromatography/mass spectroscopy. Linalool was the main constituent (58.22%). The oil was considered bioactive, showing an LC?? value of 23 μg/mL in the Artemia salina lethality test. The antifungal activity was evaluated against Microsporum canis and Candida spp. by the agar-well diffusion method and the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were established by the broth microdilution method. The essential oil induced growth inhibition zones of 28 ± 5.42 and 9.25 ± 0.5 for M. canis and Candida spp. respectively. The MICs and MFCs for M. canis strains ranged from 78 to 620 and 150 to 1,250 μg/mL, and the MICs and MFCs for Candida spp strains ranged from 310 to 620 and 620 to 1,250 μg/mL, respectively. C. sativum essential oil is active in vitro against M. canis and Candida spp. demonstrating good antifungal activity.  相似文献   

12.
The essential oil extracted from the different parts of Eryngium bourgatii Gouan: stems + leaves (E.b.SL), inflorescences (E.b.I) and roots (E.b.R), have been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). Quantitative but not qualitative differences have been found between the analysed parts. The principal compounds from the inflorescences oil were found to be phyllocladene (37.6%) and bicyclogermacrene (15.1%), while the oil from stems and leaves showed phyllocladene (20.4%), gamma-muurolene (11.8%) and (E)-caryophyllene (10.1%) as main ones. The oil from the roots presented gamma-muurolene (15.4%) and phyllocladene (15.0%) as major constituents. It is worth mentioning the presence of a diterpene, phyllocladene, as main compound of the essential oil. This is the first report on the essential oil of this species.  相似文献   

13.
The essential oil of the leaves and stems of Meum athamanticum Jacq., has been extracted by steam distillation and analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC-MS). The monoterpene fraction was predominant while the sesquiterpene one was practically absent. The principal constituents have been identified as (E)-beta-ocimene (29.6%), gamma-terpinene (17.9%), terpinolene (17.0%) and p-cymene (9.7%). Our results show that the chemical composition of the essential oil obtained of the leaves and stems of M. athamanticum from Spain is different to that obtained from plants of Germany, Italy and France.  相似文献   

14.
The essential oils obtained by hydrodistillation of the rhizomes of Alpinia aquatica Rosc. syn. Alpinia melanocarpa and Alpinia malaccensis Roscoe were analysed by capillary gas chromatography and gas chromatography-mass spectrometry. Eighteen compounds, representing 98.4% of the essential oil were identified in A. aquatica rhizome oil, with β-sesquiphellandrene in 36.5% being the major constituent, while 20 compounds representing 99.7% of the rhizome oil of A. malaccensis were identified, among which methyl (E)-cinnamate (78.2%) was the major constituent.  相似文献   

15.
The antibacterial activity of the essential oil from leaves of Juniperus phoenicea (Cupressaceae) and its chemical constituents were investigated in this study. The essential oil was obtained by hydro-distillation and analyzed by gas chromatography equipped with a flame ionisation detector (GC-FID), and gas chromatography coupled to a mass spectrometer (GC-MS). Sixty-three volatile compounds were identified representing 52 to 92% of the total oil compositions. The main monoterpenes were a-pinene (26.7-78.7%) and 6-3carene (7.6-15.4%). The antibacterial activity of J. phoenicea essential oil, when tested against both Gram-positive and Gram-negative bacteria, showed high activity against all bacteria tested, except Pseudomonas.  相似文献   

16.
The essential oil composition of Feronia elephantum Correa (family: Rutaceae) was examined by capillary gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The analysis revealed the presence of 24 constituents, of which 18 constituents were identified. Trans-anethole (57.73%) and methyl chavicol (37.48%) were the major compounds, while cis-anethole, p-anisaldehyde, (E)-jasmone, methyl eugenol, β-caryophyllene, linalool and (E)-methyl isoeugenol were also present as the minor constituents.  相似文献   

17.
The aerial parts and roots of Betonica officinalis were collected from three localities characterized by different ecological conditions to study the natural variability of the chemical composition of the essential oils in this plant. The leaves and inflorescences were collected during the flowering time, whereas the roots were collected at the end of the vegetative period. The plant material was dried at room temperature. The essential oils were obtained by micro-steam hydrodistillation and analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Overall, 69 constituents were identified in all localities and plant parts. The main compositions of the leaves in all localities were alpha-pinene, 1-octen-3-ol, beta-bourbonene, (E)-caryophyllene and germacrene D. The essential oil of the inflorescences was characterized by these main constituents: alpha-pinene, (E)-caryophyllene and trans-beta-farnesene. In all localities, the percentages of alpha-pinene and (E)-caryophyllene were higher in the inflorescences than in the leaves, whereas nonane was the main constituent in the roots.  相似文献   

18.
In the leaves of the medicinal plant Eucalyptus camaldulensis Dehnh (E. rostratus Schlecht) collected from different sampling areas of Greece the trace elements antimony, cesium, chromium, cobalt, iron, europium, rubidium, scandium, strontium, thorium and zinc were determined by Instrumental Neutron Activation Analysis. In the same samples, the essential oil was determined by steam distillation and the percent relative composition of the essential oil in 1,8-cineole, p-cymene, -pinene by gas liquid chromatography. Also the refractive index of the essential oil was determined by a refractometer. Statistical analysis included the calculation of the correlation coefficient. Multiple correlation and cluster analysis was applied to all analytical data. The results showed that the trace elements iron, chromium, cobalt and zinc are correlated with the variation of the concentration of essential oil in the examined plant. These four elements along with rubidium and essential oil content could be used for the separation of the samples into groups related to the sampling areas. Statistically significant correlation between active constituents and some trace elements and a linear negative correlation between 1,8-cineole and refractive index were found.  相似文献   

19.
The essential oil composition of the flowers of Senecio belgaumensis (Wight) Cl. was analyzed by gas chromatography and gas chromatography/mass spectrometry. Forty eight compounds were identified, representing 91.5% of the total oil. The main constituents were 1-undecanol (19.5%), beta-caryophyllene (18.9%), caryophyllene oxide (10.4%) and y-terpinene (9.2%).  相似文献   

20.
The essential oil from the different parts (inflorescences, stems+leaves and roots) of E. corniculatum Lam. gathered in Guadalajara (Spain) has been extracted by steam distillation and analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Quantitative and qualitative differences have been found between the analysed parts, although all of them contained the same principal compound, 2,4,6-trimethylbenzaldehyde, representing the 50.8%, 50.0%, and 29.8% of the total oil for inflorescences, stems+leaves and roots, respectively. Other representative constituents of the oil were similar in the different fractions: in the inflorescences compounds were found to be alpha-pinene (4.0%), chrysanthenyl acetate (4.0%), 2,4,5-trimethylbenzaldehyde (3.3%), (2Z,6E)-farnesol (2.0%), (E)-nerolidol (2.1%) and (Z)-beta-ocimene (2.1%), while the stems+leaves oil showed 2,4,5-trimethylbenzaldehyde (3.8%), alpha-pinene (3.4%), (E)-nerolidol (2.4%) and (2Z,6E)-farnesol (2.1%), and in the roots oil a phyllocladene isomer (13.0%), (E)-nerolidol (9.4%), beta-eudesmol (4.1%) and (2Z,6E)-farnesol (2.1%) were found. The presence of C-10 compounds as the main fraction for an Eryngium species is worth mentioning. This is the first report on the chemical composition of this Mediterranean endemic species.  相似文献   

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