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排序方式: 共有306条查询结果,搜索用时 31 毫秒
1.
在管式反应器中采用苯甲酸、聚乙二醇、固体古马隆树脂(S)、液体古马隆树脂(L)为添加剂来降低煤沥青中有害物质苯并芘的含量,以期使得煤沥青可绿色化应用。采用紫外-可见分光光度计分析煤沥青中苯并芘含量。考察了反应温度、反应时间、添加剂添加量、催化剂等工艺条件对添加剂脱除煤沥青中苯并芘的影响。结果表明,不同工艺条件能降低煤沥青中苯并芘的含量。在优化条件下,不同添加剂对苯并芘脱除率由高到低依次为:液体古马隆树脂、聚乙二醇、苯甲酸和固体古马隆树脂。分析其反应机理,这与催化剂的酸性相关,发生亲电取代反应。结果表明,液体古马隆树脂(L)在催化剂存在下对煤沥青中苯并芘脱除率可达73.0%,显示了良好的应用前景。 相似文献
2.
Several 2- and 4-alkylcyclohexadienones were prepared and shown to accept electrons to produce ketyl radical anions that dissociated rapidly at room temperature to release carbon-centered radicals and an aromatic phenoxide type anion. In the PET process with benzyl-substituted cyclohexadienones, initiated with triethylamine, the benzyl radicals dimerised or abstracted an H-atom from solvent. In electrochemical reductions, and in reductions with alkali metals in liquid ammonia, the benzyl radicals were further reduced to anions. 相似文献
3.
2,6- and 2,7-Dimethylanthracenes were reduced seriatim with lithium in liquid ammonia and lithium in methylamine to their 1,4,5,8,9,10-hexahydro derivatives. Two-fold epoxidation of these tetraenes provided the cis and trans diepoxides resulting from electrophilic attack at the inner double bonds. Trans diepoxide 1 has the very unusual characteristic of lacking a σ plane of symmetry but possessing an inversion center. As a consequence, the 1H NMR spectrum of C1-symmetric 1 is simplified relative to those of its isomers 5, 9, and 10. 相似文献
4.
V. V. Veselovsky A. V. Lozanova R. R. Khairetdinov N. V. Vendilo K. V. Lebedeva 《Russian Chemical Bulletin》2004,53(10):2345-2347
A simple method for the synthesis of (±)-2,6-dimethylocta-5(Z),7-diene-4-ol possessing a high pheromone activity for the bark beetle Ips typographus was developed.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2245–2247, October, 2004. 相似文献
5.
Three new serratanes were isolated from the nonsaponifiable fraction of western white pine ( Dougl.) bark. The compounds were shown to be 3β-methoxyserrat-14-ene-21α,30-diol (), 3β-methoxyserrat-14-ene-21α, 29-diol (), and 3β-methoxyserrat-14-ene-21β,30-diol (), by a combination of chemical, and spectral methods. 相似文献
6.
Two new esters, methyl 4‐(prenyloxy)dihydrocinnamate and methyl 4‐(geranyloxy)dihydrocinnamate, together with fourteen known compounds have been isolated from the stem bark of Zanthoxylum pistaciiflorum. The structures of two new compounds were determined through spectral analyses. Among the isolates, four compounds exhibited effective cytotoxicities against P‐388 and HT‐29 cell lines in vitro. 相似文献
7.
Summary A capillary zone electrophoresis method for identification and determination of aesculin and aesculetin has been established
using borate-phosphate buffer containing 30% ethanol with on-column UV detection. A detailed investigation of the influence
of changes in borate concentration, pH, applied voltage, temperature and organic modifier was then carried out. For both aesculin
and aesculetin, a linear plot of migration time (MT) against borate concentration was obtained, and ln[measured peak area
(MA)] and lnMT both gave linear plots against ln(applied voltage) with correlation coefficient r>0.999, which also resulted
in a linear correlation between MA and MT (r≥0.9998) under varied voltage. Ethanol as organic modifier to the background electrolytes
helped in separating aesculin and aesculetin from other components in ash barks. The reproducibility with relative standard
deviation in MT and in normalized peak area(NA) and linearity based on NA against concentration were evaluated. Finally, the
method was successfully applied to monitor the quality of different ash barks and to compare the effect of sample preparation
on content of bioactive components in ash bark. Results indicate that CZE promises to be applicable to quality control of
traditional Chinese medicines containing aesculin and aesculetin. 相似文献
8.
Ricardo Castanedo 《Tetrahedron letters》2006,47(6):973-976
The Birch reduction-dialkylation reaction has been studied with different aromatic carboxylic acids and primary and secondary bromides. From these results it can be concluded that it is a reasonably general reaction. However, we found important exceptions with the primary bromides: allyl bromide, β-phenethyl bromide, and 5-bromo-2-methyl-2-pentene. The unusual behavior of allyl bromide is briefly discussed. 相似文献
9.
天祝煤MRF工艺热解焦油的组成分析 总被引:5,自引:0,他引:5
本文对天祝煤MRF(MutistageRotaryFurnace)热解焦油进行了常规及元素分析,了解其基本特性;用毛细管色谱分别对焦油各馏分进行了分析,共定性定量了103种化合物,酚类化合物以低级酚(苯酚、甲酚)为主,中性化合物为多烷基芳烃衍生物、脂肪族链状烷烃和烯烃。上述分析结果为从焦油中提取酚类化工原料或将其加工成各种燃料油的可行性提供了依据。 相似文献
10.
Hui Chen Ming Tang Jinming Gao Xia Chen Zongbo Li 《Chemistry of Natural Compounds》2006,42(5):534-538
The volatile mono-and sesquiterpenes obtained from the needles and resin of Pinus armandi, P. tabulaeformis, and P. bungeana growing in the Qinling, Taibai, and Huanglong Mountain forest ecosystem were analyzed by means of GC-MS. Forty-eight constituents
were identified, and α-pinene, β-pinene, 1R-α-pinene, β-caryophyllene, cadindiene, α-caryophyllene, D-limonene, and 1S-β-pinene were the major components of the mono-and sesquiterpenes in the needles and resin. The components of the volatile
mono-and sesquiterpenes from the needles and resin at Qinling, Taibai, and Huanglong Mountains had remarkable differences
in three pine species, whereas the monopertene content such as α-pinene, β-pinene, D-limonene, and camphene were mostly changed in the growing stage. The intraspecies variation in the different ecosystems
can be attributed to the species’ geography and genetic variation, and even the adaptation of the pine species to different
ecological environments. Moreover, monoterpenes and sesquiterpenes can be induced by the attack of bark beetles, of which
the α-pinene, β-pinene, 1R-α-pinene, 1S-α-pinene, b-myrecene, and β-caryophyllene contents had positive relations with the attacking Dendroctonus armandi and D. valens.
Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 430–433, September–October, 2006. 相似文献