用动态累积分批精馏法从莰烯下脚料中提取柠烯

动态累积分批精馏法具有分离效率高的优点,用于从莰烯下脚料中分离柠烯较之传统分批蒸馏方法,在填料层高度减少了一半,分离时间减少了一半的情况下,效率提高约７％．     

有机碱对莰烯直接乙酰化的影响

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。     

糠醛-环己醇-莰烯三元气液平衡数据的测定

利用自制气液平衡装置测定糠醛-环己醇、糠醛-莰烯和糠醛-环己醇-莰烯在101.3kPa下的气液平衡数据。对所测得的数据进行关联与计算,得到Wilson方程参数。代入Wilson模型,计算出101.3KPa条件下糠醛-环己醇、糠醛-莰烯2组二元体系的温度与气相组分的质量分数,与实验值比偏差不大,说明实验可行。用面积积分法验证两组二元气液平衡数据的热力学一致性,结果符合要求。通过测定糠醛-环己醇-莰烯三元气液平衡数据,并进行拟合,得到421.5K时糠醛的气相物质的量分数相对最高,环己醇的气相物质的量分数又相对最低,即在该温度下分离糖醛分环己醇较好,可为工程上分离糠醛和环己醇提供理论依据。     

酸改性膨润土负载ZnCl2催化松节油直接异构-歧化反应研究

以自制酸改性膨润土负载ZnCl2为催化剂,采用傅里叶红外光谱( FT-IR) 和气相色谱-质谱联用(GC-MS)技术对松节油直接催化异构-歧化液相反应进行研究.FT-IR 分析表明,在反应产物谱图中蒎烯吸收峰3023 cm-1、1653 cm-1和3067 cm-1消失,苯环的骨架吸收峰1645 cm-1 和1456 ...     

Allelopathic Effects of Volatile Monoterpenoids Produced by <Emphasis Type="Italic">Salvia leucophylla</Emphasis>: Inhibition of Cell Proliferation and DNA Synthesis in the Root Apical Meristem of <Emphasis Type="Italic">Brassica campestris</Emphasis> Seedlings

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.     

SO42-/SnO2固体超强酸的共沸除氯法制备、表征及其催化α-蒎烯异构化

采用共沸除氯法制备SO42-/SnO2固体超强酸,将其应用于α-蒎烯异构化。该催化剂的最佳制备条件：浸渍液硫酸浓度为1.5 mol/L,焙烧温度为550 ℃下焙烧3.0 h;反应最佳条件为：反应温度为110 ℃下反应3.0 h,催化剂用量为松节油中α-蒎烯质量分数的5%;在该条件下,α-蒎烯转化率为100%,莰烯选择性为64.85%。采用FT-IR、XRD、TG-DTA、SEM、BET对催化剂进行表征。结果表明：相同制备条件下,共沸除氯法制备的SO42-/SnO2较溶胶凝胶法与沉淀法制备的SO42-/SnO2催化活性高,超强酸中心多,颗粒小且均匀,团聚少。     

Camphene as a novel solvent for polypropylene: Comparison study based on viscous behavior of solutions

Polypropylene solutions were prepared using three solvents: paraffin oil, decalin, and a novel solvent—camphene. The effects of these solvents were evaluated based on the activation energy of flow and on their melting‐point depression. Experimental results indicate that the values of the viscosity of the resulting solutions were close to Newtonian behavior in the shear rates below 34 s⁻¹. The Arrhenius–Frenkel–Eyring equation was used to describe the dependence of the viscosity on the temperature. In addition, the viscosity increased with the polymer concentration, which can be described by a power‐law correlation. The activation energy of the flow of the polypropylene/camphene solution was the lowest and that of the paraffin oil solution was the highest. Correspondingly, the melting‐point depression of polypropylene solutions in camphene and decalin were substantially lower than that in paraffin oil (71, 61, and 33°C, respectively). These results indicate that lower activation energies of flow correspond to higher values of melting‐point depression. Moreover, analysis of variance indicated that the primary factor affecting the viscous behavior is the concentration, followed by the solvent and the temperature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2068–2074, 2000