One Step Method for the Synthesis of 2-Hydroxy-1,4-cineole Catalyzed by Peroxoheteropolyoxomolybdotungstate

以过氧磷钼钨酸烷基吡啶盐Cat-PMo2W2O24为氧化-酸双功能催化剂,在质量分数为30%的双氧水存在下,催化松油烯-4-醇(Ⅰ)一步合成了2-羟基-1,4-桉树脑(Ⅱ)。溶剂种类、催化剂用量、双氧水用量能明显改变催化反应体系的相态、酸性或酸量,进而影响反应转化率和产率。最佳的反应条件为:松油烯-4-醇12 mmol,溶剂氯仿5 m L,催化剂用量为4.20%(以松油烯-4-醇的质量计),双氧水用量为0.91(以双氧水与松油烯-4-醇的摩尔比计),反应温度为25℃,反应时间为30 min;在该条件下,松油烯-4-醇的转化率和2-羟基-1,4-桉树脑的产率分别为96.2%和70.1%。Abstract: 2-Hydroxy-1，4 -cineole( Ⅱ) was obtained from terpinen-4-ol( Ⅰ) via a one-step synthetic method by using peroxoheteropolyoxomolybdotungstate ( Cat-PMo2W2O24 ) as redox-acidic bifunctional catalyst in the presence of H2O2 aqueous solution of a mass fraction of 30%． There were obvious effect of various reaction parameters such as solvent type，catalyst dosage，and the amount of hydrogen peroxide on the phase state，acidity or acid amount of the reaction system， resulting in the changes of the conversion rate ofⅠand the yield of Ⅱ． Under the optimum conditions Ⅰ，12 mmol; chloroform as solvent，5 mL; catalyst dosage，4. 20% ( mass fraction based on the substrate) ; temperature，25 ℃; the molar ratio of H2O2 toⅠ，0. 91; reaction time，30 min，96. 2% conversion of Ⅰ with 70. 1% yield towards Ⅱ was achieved．国家自然科学基金(31460174);广西科学研究与技术开发计划项目(1348006-10);广西高校大学生创新创业训练计划项目(201410608047

菠菜硝态氮累积和还原与植株生长的关系/Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth[J]

通过盆栽试验,以两个硝态氮含量差异显著的菠菜品种为供试材料,在不同生长时期,测定了叶柄、叶片干重、水分含量、硝态氮含量及叶片内源和外源硝酸还原酶活性,研究菠菜硝态氮累积和硝酸还原酶活性的动态变化及其与植株生长变化的关系.结果表明,随生长期后移,叶柄、叶片及地上部干重和水分含量先增加而后降低,硝态氮含量则持续降低,低硝态氮累积品种S9的下降更为明显,出苗后52d和62d地上部分别降低了100%和89.7%;叶片内源和外源酶活性则随植株生长量增加而增加,高硝态氮累积品种S4增加(379%和199%)更明显,之后该品种酶活性随植株生长量降低而显著下降,品种S9却显著增加,分别为121%和288%.生长前期,品种S4硝态氮含量、干重增长速率及内源、外源酶活性均显著高于品种S9,内源/外源酶活性比值却明显低于后者;生长后期,除外源酶活性和内源/外源酶活性比值外,品种间差异均不明显.因此,生长前期高累积品种硝态氮含量降低较少,主要原因可能是其内源/外源酶活性比值(70.7%)较低,生长后期该品种的内源/外源酶活性比值(98.2%)显著增加后,硝态氮含量迅速下降进一步证明了这一推测.综合上述结果可知,内源/外源酶活性比值更能揭示植株生长变化引起的品种间硝态氮含量变化差异