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1.
Salvia leucophylla, a shrub observed in coastal south California, produces several volatile monoterpenoids (camphor, 1,8-cineole, -pinene, -pinene, and camphene) that potentially act as allelochemicals. The effects of these were examined using Brassica campestris as the test plant. Camphor, 1,8-cineole, and -pinene inhibited germination of B. campestris seeds at high concentrations, whereas -pinene and camphene did not. Root growth was inhibited by all five monoterpenoids in a dose-dependent manner, but hypocotyl growth was largely unaffected. The monoterpenoids did not alter the sizes of matured cells in either hypocotyls or roots, indicating that cell expansion is relatively insensitive to these compounds. They did not decrease the mitotic index in the shoot apical region, but specifically lowered mitotic index in the root apical meristem. Moreover, morphological and biochemical analyses on the incorporation of 5-bromo-2-deoxyuridine into DNA demonstrated that the monoterpenoids inhibit both cell-nuclear and organelle DNA synthesis in the root apical meristem. These results suggest that the monoterpenoids produced by S. leucophylla could interfere with the growth of other plants in its vicinity through inhibition of cell proliferation in the root apical meristem.  相似文献
2.
本文采用在微波辐照下,以自制MoO3/ZrO2型固体超强酸为催化剂,通过改变微波功率、时间、催化剂焙烧温度及用量等条件,研究了莰烯与甲酸反应转化为甲酸异龙脑酯的工艺。实验结果表明:酯化反应的适宜工艺条件为:莰烯与甲酸摩尔比为1∶1.2,微波功率320W,反应时间75min,催化剂焙烧温度为700℃,用量为莰烯质量的5%。在上述条件下,甲酸异龙脑酯收率80.2%。  相似文献
3.
介绍了水合法合成樟脑脱氢工艺中使用回收莰烯取代二甲苯作溶剂,降低了生产成本,稳定了产品质量,减少了环境污染,取得了良好的社会、经济效益。  相似文献
4.
对由树脂催化莰烯直接水合成异龙脑过程中的副产油,利用固体酸催化回收莰烯和异丙醇。试验表明:催化剂用量为0.5%,反应强度150℃,反应30min,副产油回收率大于97%。  相似文献
5.
Abstract The kinetics of camphene production in liquid phase from α-pinene was experimentally determinedin an isothermal batch reactor.To this end,a sulfated ZrO_2 catalyst was used and the reaction studied in thetemperature range of 370-403K.By analyzing the experimental data,second reaction order for α-pinene wasfound.A kinetic model is presented which includes term for the catalyst load used.The specific rate constant at393K was 2.19×10~(-3)mol.L~(-1),min~(-1),the activation energy being 93kJ.mol~(-1).Both Vaues are within the rangeof literature results.  相似文献
6.
刘辉  肖转泉  黄勇红 《化学试剂》2003,25(1):33-34,36
研究了在含氮有机碱存在下的莰烯直接乙酰化反应,结果表明,在反应中加入与莰烯等摩尔的六氢吡啶,有利于莰烯乙酰化反应,在反应液中的酰化产物ω-乙酰基莰烯含量最高达到56%,大大超过异构化产物乙酸异冰片酯。  相似文献
7.
Scots pine populations contain individuals with widely differing amounts and composition of monoterpenes and exist as one of two chemotypes: with or without Δ3-carene. We investigated the significance for ecological studies of two types of variation in monoterpenes: (1) the inherent variability in the concentration of monoterpenes or their relative amounts in needles of seedlings, saplings, and mature trees; and (2) phenological variation in developing needles. The relative composition of needle monoterpenes in 5-year-old saplings changed during the needle development period until the final composition was reached upon needle maturity. Changes in composition depended on chemotype. Needles of the “no-Δ3-carene” chemotype had higher absolute concentrations of α-pinene, β-pinene, camphene, and total monoterpenes than “Δ3-carene” chemotype. For the “Δ3-carene” chemotype, the relative concentration of Δ3-carene during the needle growing season and immediately after emergence of seedlings was higher compared to that reached at needle maturity. Repeated removal of single needles (at weekly intervals during growth) from 5-year-old saplings did not influence the composition of monoterpenes. Within a natural Scots pine dominated woodland, 18% of mature Scots pines (N = 574) belonged to the “no-Δ3-carene” chemotype. Chemotypic variation within populations means that the statistical power with which differences in monoterpene concentrations can be detected is lower when sampling from the whole population compared to sampling within chemotypes. Reduction of this background variation and accounting for chiral variation if present, would significantly aid efficiency, interpretation, and understanding of processes in chemical and ecological research. One method for achieving this is the screening of plants for chemotypes before the establishment of experiments or field sampling regimes. We present a summary of suitable analytical methods for needle tissue that facilitates this prior screening.  相似文献
8.
The subsocial tenebrionid Parastizopus armaticeps Pér. is parasitized by the closely related Eremostibes opacus Koch (Coleoptera: Tenebrionidae). We found that the pygidial defensive secretions of both species are similar and contain a mixture of 1,4-benzoquinones, 1-alkenes, and monoterpene hydrocarbons. The 1-alkenes are dominated by 1-undecene, with admixtures of 1-tridecene in both species and 1-pentadecene in P. armaticeps only. Methyl- and ethyl-1,4-benzoquinone are the major quinones of the secretions of both species. The monoterpene fractions consist of (−)-α-pinene, (−)-camphene, sabinene, (−)-β-pinene, and (−)-limonene. Volatiles trapped with Porapak Q at the entrance to the breeding burrows of P. armaticeps were identified as components of the defensive secretion. However, in contrast to the secretion, the 1,4-benzoquinones were almost completely absent in the volatiles. Bioassays investigating attraction showed that the cleptoparasite E. opacus was drawn to the monoterpene hydrocarbons, produced by P. armaticeps, and deterred by the 1,4-benzoquinones. The 1-alkenes had no effect. Among the monoterpenes, only (−)-camphene was attractive to E. opacus. This is one of the rare cases of chemical exploitation of defensive allomones, and the first based on odor homology. We have drawn an evolutionary scenario including various functional changes in the defensive secretion compounds, leading to the kairomonal exploitation.  相似文献
9.
工业莰烯在耐高温离子交换树脂DCP催化作用下与无水乙醇反应生成了异龙脑基乙醚。探索了反应温度、反应时间、催化剂用量,以及工业莰烯与无水乙醇的配比对反应的影响。结果表明,异龙脑基乙醚合成的优化条件为:m(工业莰烯):m(无水乙醇)=10:7~10:9, DCP用量占物料总质量的 15%,反应温度(75±1)℃ ,反应时间6~9 h,工业莰烯转化率达到 71.5%,选择性达到 96.8%。  相似文献
10.
Zinc containing aluminophosphates (ZAPO-5 and ZAPO-11) were synthesized hydrothermally using triethylamine and dipropylamine as templates. Structures were confirmed from X-ray powder patterns and unit cell parameters were calculated by a standard least-squares refinement technique. The isomorphous substitution of zinc in the aluminophosphate framework is evidenced by the considerable increase in unit cell volume and from MAS-NMR spectra. Acidity was determined by the TPD-TGA method which shows three different strengths of acid sites. FT-IR, chemical analysis and BET surface area were also reported. The physico-chemical properties of the catalysts were correlated towards the vapour phase transformation of camphene and the results are fully discussed.  相似文献
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