一锅法高产率合成α-羰基苯丁酸

用苯丙酸乙酯与草酸二乙酯合成α 羰基苯丁酸。采用一锅法代替文献中的两步反应 ,用稀硫酸代替文献中盐酸 -醋酸混酸水解 ,并用正交设计法对工艺条件进行优化 ,得出最佳工艺条件为 :n(苯丙酸乙酯 )∶n (草酸二乙酯 ) =1 0∶4 0 ,缩合 1 5h ,用w (H2 SO4) =2 0 %的硫酸水解15h ,产品收率由文献值的 5 7 2 %提高到 89%     

碳酸二甲酯市场现状及发展前景

介绍了碳酸二甲酯的国内外市场及发展前景，总结了国内市场特点，提出了我国发展碳酸二甲酯的建议。     

化学发光材料双(2,4,6-三氯苯基)草酸酯的合成

草酸酯是过氧草酸酯类化学发光所必需的一种要素化合物，作者合成了一种能提供高强度化学发光的草酸酯即双（２，４，６ 三氯苯基）草酸酯，并以质谱验证了结构。     

高分子金属配合物用于合成碳酸二甲酯的催化性能

研究了以二氧化硅负载聚丙烯腈-丙烯酰胺-金属(PAN-AM-M)配合物为催化剂，在环氧氯丙烷存在下，由甲醇和二氧化碳直接合成碳酸二甲酯的反应活性。考察了反应条件的影响。结果表明，PAN-AM-Zn表现出较高活性，合成碳酸二甲酯的最佳反应条件为：甲醇与环氧氯丙烷的原料配比为4：1，反应温度130℃，催化剂用量2％(反应物料质量百分数)。     

草酸盐共沉淀法制备SrAl2O4：Eu^2＋，Dy^3＋发光粉体的研究

用草酸盐共沉淀法制备了SrAl2O4：Eu^2＋，Dy^3＋发光粉体，用差热分析仪、X-射线衍射仪、扫描电镜和荧光分光光度计对制备产物进行了测试分析，并对烧成温度，Dy^3＋、H3BO3掺杂对荧光体发光特性的影响进行了讨论，确定了草酸盐共沉淀法的最佳烧成温度为1200℃，Dy^3＋最佳掺杂摩尔分数为0．002，硼酸为0．3。     

沙门氏菌产草酸盐降解酶的性质及其酶作用条件

沙门氏菌产草酸盐降解酶,能够降解草酸或草酸钙。对草酸盐降解酶性质作了分析,结果表明,酶作用的最适温度为40℃,最适pH值为7.0,最适底物浓度为30%,金属离子Na+、Mg2+、K+、Cu2+、NH4+对酶无明显的激活抑制作用。     

二甲基醚喷雾特性试验

利用纹影光学系统和高速数码摄影机对定容燃烧弹内的新型代用燃料二甲基醚的喷雾和蒸发过程进行了系统的研究,并与柴油的喷雾和蒸发特性进行了比较。结果表明,二甲基醚的喷雾射程和锥角随环境参数变化的规律与柴油相似,但在相同条件下,二甲基醚的喷雾射程比柴油小,喷雾锥角比柴油大;二甲基醚的蒸发速度比柴油快。在喷雾的发展过程中,二甲基醚燃料在喷雾影像区域内的分布比柴油均匀。     

Ti(OC4H9)4-PbO均相催化反应蒸馏合成碳酸二苯酯

通过对碳酸二甲酯与苯酚酯交换法反应蒸馏合成碳酸二苯酯的研究,筛选合适的催化剂和寻找最佳的工艺条件,为将来碳酸二苯酯的工业化打下基础.实验结果表明在常压下,温度132℃,原料中苯酚与碳酸二甲酯的摩尔配比为21,苯酚与催化剂的摩尔配比为10.012,钛酸四丁酯与氧化铅的摩尔配比为11,反应时间12 h,碳酸二甲酯总转化率为45.43%,碳酸二苯酯产率为26.33%,碳酸苯甲酯产率为19.10%,碳酸二苯酯的选择性为57.96%,且无苯甲醚和CO2生成.所选催化剂Ti(OC4H2)4-PbO的催化性能明显优于二丁基二月桂酸锡和PbO.     

Phase transition in L-alaninium oxalate by photoacoustics

Phase transition in L-alaninium oxalate is studied by using TG, DTA and photoacoustic spectroscopy. A sharp transition at 378 K by photoacoustics is observed whereas at the same temperature the endothermic energy change observed by TG and DTA is not very sharp. This is discussed in detail with reference to the other known data for the organic crystals.     

A preparation method for observing intracellular structures by scanning electron microscopy

In order to observe intracellular structures by scanning electron microscopy, excess cytoplasmic matrix must be removed from the fractured surface of cells. Previously we reported an Osmium-DMSO-Osmium method devised for this purpose. This method is very effective in revealing intracellular structures, but requires osmium tetroxide for initial fixation with some consequent disadvantages. In the present study, a revised Osmium-DMSO-Osmium method is reported, in which an aldehyde mixture is used as the initial fixative instead of osmium tetroxide. As fixation is carried out by perfusion in this revised method, better preservation of fine structures is achieved than by the original method, especially in the central nervous tissue which tends to suffer from post-mortem degeneration. Moreover this method can be applied to cytochemical studies of intracellular structures with a scanning electron microscope (SEM). In this study, acid phosphatase of lysosomes is demonstrated in a coloured SEM micrograph.