合成原料对LiMn2O4电化学性能的影响研究

采用固相法分别以不同原料合成尖晶石LiMn2O4。采用X射线衍射、扫描电子显微镜、循环伏安及恒电流充放电等技术检测和分析合成产物的物相、形貌及电化学性能。研究表明,与采用电解MnO2为原料合成的LiMn2 O4相比,采用Mn3 O4为原料合成的LiMn2 O4粉末X射线衍射峰强度更大,室温下以0.2 C倍率充放电循环30次时,首次放电比容量和容量保持率分别为128.7 mA.h/g和98.4%,高于以电解MnO2为原料合成LiMn2 O4的123.7 mA.h/g和85.0%。55℃循环时,采用Mn3 O4为原料合成的LiMn2 O4容量保持率比采用电解MnO2为原料合成LiMn2O4的高10.7%。     

离子液体表面活性剂的合成与应用(Ⅱ)——离子液体表面活性剂的合成

按照离子液体表面活性剂的种类,分别介绍了不同类型离子液体表面活性剂的合成方法。阳离子型离子液体表面活性剂可以采用直接季铵化法、复分解法和离子交换法合成;阴离子型离子液体表面活性剂是采用传统阴离子表面活性剂与离子液体在有机溶剂或水/有机溶剂中复分解反应完成的;两性离子液体表面活性剂通常采用直接季铵化法合成;双子和Bola型离子液体表面活性剂与传统双子和Bola型表面活性剂的合成方法相似;微波和超声等新的辅助合成方法将明显促进离子液体表面活性剂的合成。     

Schlesinger法合成硼氢化钠工艺条件及优化途径

目前工业化合成硼氢化钠的工艺有Schlesinger法和Bayer法,而Schlesinger法是工业化合成硼氢化钠应用最广的工艺,其关键步骤为氢化钠和硼酸三甲酯的合成。本文一方面从氢化钠的合成、硼酸三甲酯的合成及硼氢化钠的合成3个方面详细论述了Schlesinger法合成工艺进展情况;并指出目前方法存在的问题,如采用油液分散金属钠法合成的氢化钠活性差,制约了氢化钠的应用,硼酸三甲酯工业合成过程中过多使用浓硫酸造成环境严重污染。另一方面对Schlesinger法工艺改进提出了几点设想,如企业全流程合成硼氢化钠可节约外购成本和仓储成本;硼酸三甲酯的合成取代浓硫酸的应用,提纯采用盐析的方法均可以减轻环境污染;硼氢化钠水解过程中采用稀液碱溶液代替淡水,可避免硼氢化钠水解,提高产品收率。     

月桂酸单乙醇酰胺合成工艺研究

月桂酸单乙醇酰胺是一种非离子表面活性剂,现阶段大量采用一步法合成工艺,副反应较多。通过对月桂酸单乙醇酰胺合成催化剂研究和合成工艺优化,采用新型的三元金属氧化物为催化剂,采用二步法合成工艺,明显减少了副反应的产生,提高了有效成分的含量。     

氧化硅有序介孔材料MCM-41的微波水热合成及用于组装ZnO纳米粒子

与传统水热合成工艺相比,采用微波水热合成新工艺可以快速合成比表面积大、孔体积和孔径大、孔径分布范围更窄、孔洞呈六方排布的有序介孔材料MCM-41.微波水热合成工艺合成的MCM-41具有合成效率高、成功率高等特点,为此类介孔材料商业化提供了高效的技术手段.采用传统水热工艺合成MCM-41通常需要48～72 h,而采用微波水热合成技术仅需要30 min.采用X射线粉晶衍射(XRD),氮气吸附等技术手段对合成MCM-41材料的物相、比表面积、孔体积、孔径等进行了表征.采用微波水热合成MCM-41的工艺参数为:微波处理的温度120 ℃,时间30 min,微波辐射功率500 W,经过滤、洗涤、干燥、焙烧等处理后,得到的MCM-41具有六方排布的孔系,晶格常数a0=4.4nm,比表面积可达1113 m2/g,平均孔径为2.7 nm,与选用同样配方采用传统水热合成工艺合成的MCM-41的性能相当,却极大提高了合成效率.采用微波水热合成工艺,同样可以合成立方晶系的MCM-48和六方晶系的SBA-15等介孔氧化硅分子筛材料.此外,在微波合成的MCM-41中采用液相工艺成功组装了ZnO纳米粒子,并对组装在MCM-41中的纳米ZnO粒子进行了光催化降解苯酚的实验研究.     

游梁式抽油机传动系统动力合成装置研究

针对游梁式抽油机工作能耗大和效率低等不足,提出了采用液压技术回收能量的节能方案。该方案的核心部分是行星轮动力合成装置。分析行星轮传动比和转矩关系后完成了动力合成装置的结构设计,并通过Pro/E、Adams对其进行三维建模和运动仿真,得到了合成装置的转速、扭矩关系曲线。仿真结果表明采用行星轮动力合成装置进行动力合成是可行的。     

维生素A合成工艺评述

本文首先介绍了维生素A的Roche和BASF两条合成工艺路线,指出了两条工艺路线的不同技术特征和关键技术难点。阐述了BASF技术路线关键合成步骤的技术开发动态。对国内外工业合成维生素A主要采用的Roche合成工艺的关键中间体的合成进行重点阐述,总结了值得深入研究的合成新工艺、新方法和技术研究开发方向。     

无磷洗涤剂助剂4A沸石的新进展

详细介绍了近年来4A沸石在合成方面(合成所用原料、合成工艺等)的新发展．并指出采用廉价易得的原料和简单先进的合成工艺合成高性能的4A沸石将会极大地推动无磷洗涤剂的快速发展。     

氨基功能化可降解聚酯共聚物的制备及性能

采用三步法合成了一种新型功能化乙丙交酯共聚物,主要包括端羟基乙丙交酯聚合物PLGA-OH的合成、含保护基乙丙交酯聚合物PLGA-BOC的合成以及端氨基乙丙交酯聚合物PLGA-NH_2的合成。采用红外光谱、核磁共振光谱、GPC以及DSC对合成的共聚物PLGA-NH_2及其中间产物进行了表征和分析。结果表明:此合成工艺路线是成功的,其为制备功能性聚酯共聚物开辟了一条新途径。     

二种固相合成艾塞那肽方法比较

介绍了两种艾塞那肽的合成方法,为艾塞那肽规模化生产方法的选择提供有意义的参考。通过采用经典的固相逐个延伸法和固相四片段片段合成方法,并用两种方法分别合成艾塞那肽,对结果进行了分析和讨论。结果表明,综合工艺难度、工艺稳定性、合成成本等方面因素考虑,艾塞那肽合成采用逐个延伸法合成综合效果更优。     

NSP窑设计参数的优化及对传动功耗影响篚计算和分析探讨

根据早期日产2000t,Ф4．0m×60m窑的生产和部分研究成果,结合当前最新生产数据研究建立了以物料停留时间、物料负荷率、窑内物料量和物料运动功耗四个公式为主的NSP窑设计参数优化和传动功率计算模型。介绍了Ф4．0m×60m,斜度4．0％的回转窑的运行参数与功率计算实例,在此基础上提出了NSP窑设计中应采用大斜度、大直径、小长径比的增产节能新设计理念。     

Inhibiting effect of citric acid on the pitting corrosion of tin

Potentiostatic and potentiodynamic studies were carried out to establish the inhibiting effects of citric acid on the pitting corrosion of tin. The critical potential (Ecrit), which leads to pitting or general corrosion, was determined in sodium perchlorate solution in the pH range 1.0 to 4.0. Pit nucleation and growth, at pH4.0, can be described by instantaneous nucleation followed by progressive nucleation. The results show that the minimum acid concentration needed to inhibit pitting of tin is 10–2m. Pitting occurrence by direct interaction between metal and perchlorate anions was observed.     

木聚糖酶最适pH值的研究

研究了以里氏木霉RutC - 3 0合成的木聚糖酶的最适pH值范围。结果表明 ,内切—木聚糖酶的最适pH值范围在 4.0～ 5 .0之间 ,β—木糖苷酶的最适pH值范围在 3 .0～ 4.0之间。研究还表明 ,与内切—木聚糖酶相比 ,pH值对β—木糖苷酶的影响更大。当pH值为 4.0时 ,酶水解总糖得率最高 ,适于制备木糖 ,而当pH值为 5 .0～ 6 .0时 ,较适于制备木低聚糖。     

非焦油型双组分聚氨酯防水涂料的研制

通过一定比例合成含有NCO的聚氨酯预聚体为A组分,将粉料、聚醚、MOCA、助剂等制成B组分,将A、B组分按质量比1∶2混合成膜制得非焦油型双组分聚氨酯涂料。探讨了NCO含量、MOCA、催化助剂、消泡剂对双组分聚氨酯涂料的影响,结果表明:NCO含量在4.0%~4.6%、MOCA含量在2.5%~4.0%、催化剂在0.08%~0.12%、消泡剂在0.3%~0.7%,可以制得性能优异的双组分聚氨酯涂料。     

pH值对N-异丙基丙烯酰胺与甲基丙烯酸共聚形成微凝胶的影响

在pH值为4．0和7．0的水介质中分别采用乳液聚合法使N-异丙基丙烯酰胺（NIPAM）和甲基丙烯酸（MAA）共聚,合成了具有温度／pH双重刺激响应性的P（NIPAM—CO—MAA）共聚微凝胶。傅立叶红外变换光谱、元素分析和电位滴定分析结果表明,在pH为4．0条件下合成的微凝胶中MAA单元含量偏高,微凝胶的粒径随着MAA用量的增加而增大,而pH为7．0时合成的微凝胶的粒径随着单体MAA用量的增加而减小。通过动态激光光散射测试P（NIPAM—CO—MAA）微凝胶的动力学直径随介质温度或pH值的变化关系发现,pH为4．0条件下合成的微凝胶具有更明显的pH刺激响应性,其温度刺激响应性受介质pH值的影响较大,表明MAA单元有可能更均匀地分布于微凝胶聚合物网络中。     

Chitosan microgel: Effect of cross-linking density on pH-dependent release

Chitosan microgels were prepared by a spray-drying method using glutaraldehyde (GA) as a cross-linker. Two kinds of microgels, so-called soft microgel and hard microgel, were prepared using a chitosan to GA ratio of 1: 0.08, and 1: 0.67, respectively. The surfaces of hard microgels were more even that those of soft microgels. The swelling ratio, a measure of degree of swelling, of the soft microgel was pH-sensitive, and it decreased from 1,765% to 1,230%, when the pH increased from 4.0 to 9.0. The deprotonation of amino groups of chitosan could account for the decrease in swelling ratio. The swelling ratio of hard microgels was almost invariable in response to pH change (4.0 to 9.0), and it was much less than that of soft microgels, possibly due to the high cross-linking density. The degree of release from the soft microgels decreased from 65% to 12% when the pH of medium increased from 4.0 to 6.0. FITC-dextran would readily diffuse out of the microgel, possibly due to the larger meshes of the microgels in a strong acidic condition (e.g., pH 4.0). However, the degree of release increased from 12% to 82% when the pH of medium increased from 6.0 to 9.0. In this pH range, the fluorescence dye is believed to be released mainly by a squeezing-out.     

正交试验优化尿囊素合成工艺

以乙醛酸、尿素为原料,液体无机酸为催化剂合成尿囊素.采用正交试验法考察原料配比、反应温度、反应时间、催化剂种类及其用量等因素对尿囊素收率的影响,确定了最佳反应条件:n(尿素):n(乙醛酸)=4.0,85%磷酸4.0 mL,80℃下反应4 h,尿囊素收率可达62.3%.方差分析表明:原料配比、催化剂种类及其用量、反应时间...     

紫外分光光度法测定双酚S(英文)

建立了测定双酚S的紫外分光光度法。在pH值为6.0的磷酸盐缓冲溶液中,双酚S浓度在4.8×10-7~4.0×10-5mol.L-1范围内与其吸光度值呈显著线性相关,相关系数为0.9999,相对标准偏差为0.12%,检测限为4.0×10-7mol.L-1。该方法快速、灵敏,可用于常见样品中双酚S的测定。     

Protein-Based Microencapsulation with Freeze Pretreatment: Spray-Dried Oil in Water Emulsion Stabilized by the Soy Protein Isolate–Gum Acacia Complex

Spray-dried microparticles with lipid cores that dissolve β-carotene were prepared using a technique based on the complexation of soy protein and gum acacia. A freeze-pretreatment was applied to modify the resultant properties of the dried particles. An oil in water emulsion stabilized by soy protein isolate was mixed with gum acacia. The pH of the solution was adjusted to a selected value; this solution was frozen and thawed under controlled thermal protocols, then spray-dried to obtain the final products. Complexation was induced on the surface of the oil droplets owing to electrostatic interactions that occur below the isoelectric point (ca. pH 4.0) of the employed soy protein isolate. The freeze-pretreatment prior to spray-drying was expected to induce this interaction by freeze concentration and to control the kinetics of complex formation. When solutions with a pH of 4.0 and 3.0 were spray-dried, the encapsulation of β-carotene had similar efficiencies. The freeze-pretreatment was observed to have a significant effect on the specimens prepared from the solution with a pH of 4.0. Slow freezing conditions successfully improved the encapsulation efficiency and simultaneously reduced the amount of surface oil. Moreover, this pretreatment augmented the mass transfer resistance of the shell matrix, so that the release rate of dissolved β-carotene in the lipid core could be retarded.     

Rapid separation of gangliosides using strong anion exchanger cartridges

A method utilizing strong anion exchanger cartridges (InertSep SAX) was developed to separate gangliosides. Total lipids extracted from rat brain is able to be rapidly separated into neutral and acidic lipids rapidly. Neutral lipids were passed through the SAX cartridge while acidic lipids adsorbed onto the cartridge and were eluted by chloroform/methanol/4.0 M aqueous ammonium acetate (5:10:1, by volume). Moreover, various kinds of gangliosides (GM1, GD1a, GD1b, GT1b) were separated individually according to their characteristics by elution with increasing concentration of ammnonium acetate (0 - 4.0 M). The gangliosides yield of this procedure was higher than 95%.