盐析结晶法制取硝酸钾研究

硝酸铵与氯化钾复分解反应生产硝酸钾与氯化铵工艺，硝酸钾结晶率比较低，一般为45％-55％。为提高硝酸钾结晶率，研究了采用添加盐析剂的盐析结品法制取硝酸钾新工艺，通过盐析剂的盐析作用，硝酸钾与氯化铵在溶液中的有效浓度提高，从而使更多硝酸钾与氯化铵结晶析出，盐析剂始终在母液中循环并发生盐析作用。试验表明，盐析结晶法制取硝酸钾工艺可以使硝酸钾结晶率提高到80％。盐析结晶法制取硝酸钾最佯工艺条件：盐析剂添加量为硝酸钾量的40％（物质的量分数），硝酸钾结晶溶液质量分数50％～55％，硝酸钾冷却结晶终点温度为25℃，氯化铵溶液蒸发质量分数70％，氯化铵结晶终点温度55—65℃。     

超声波对生物大分子盐析的作用研究

在蛋白质-水胶体溶液中加入无机盐,利用蛋白质盐析的原理分离蛋白质。研究了不同频率超声波对蛋白质盐析的影响,证明超声技术可加速盐析速度。     

叔丁醇水溶液的盐析分离

叔丁醇水溶液用Ｋ２ＣＯ３进行盐析，可使叔丁醇提浓至９５％。多次盐析可显著减少盐用量。盐析分相后的盐水经蒸发浓缩后，可以作为盐析重复使用。     

NaCl盐析法从猪血粉水解液中提取L-亮氨酸

以NaCl为盐析剂从猪血粉水解液中盐析沉淀L-亮氨酸,确定了盐析沉淀所需的时间,考察了温度、pH值、NaCl加入量等因素对L-亮氨酸盐析沉淀率的影响。结果表明:盐析剂NaCl在原料液全溶解后搅拌半小时盐析沉淀率基本上达到最大值;低温对于盐析沉淀是有利的,工业生产中可在室温下或低温下进行;在溶液的pH值约为2时,NaCl存在下L-亮氨酸以二亮氨酸盐酸盐形式析出,沉淀率达到最大;溶液中氯化钠浓度越高盐析沉淀率越高,工业生产上可按0.35g/mL的比例加入NaCl。室温下控制猪血粉水解液的pH值为2,按0.35g/mL原料液的比例加入NaCl盐析出二亮氨酸盐酸盐,经精制得L-亮氨酸产品,产品符合《中华人民共和国药典》(2000年版二部)质量标准,L-亮氨酸的平均提取率为82.36%。     

盐析结晶法分离铬酸钾

关联了不同温度下K2CrO4在K2CrO4-KOH-H2O体系中的溶解度数据，分析了从K2CrO4-KOH-H2O体系中通过盐析结晶方式分离K2CrO4的可能性；通过K2CrO4-KOH-H2O体系中K2CrO4的盐析结晶实验，得出了初级成核现象发生时，体系的最大过饱和度与过饱和速率之间的动力学关系式及结晶过程中盐析剂浓度、盐析结晶终点K2CrO4收率、溶液体积等工艺参数间的关系，探讨了以KOH作为盐析剂，采用盐析结晶方法从K2CrO4-KOH-H2O体系中分离提纯K2CrO4的可行性，为K2CrO4的高效分离提供了一种新思路。     

盐析萃取应用于乙酸乙酯的提浓

采用盐析萃取应用于稀乙酸为原料制备己酸乙酯的提浓,对不同的萃剂比和含水不同的乙酸乙酯的盐析萃取效果进行了探讨,经盐析萃取可把乙酸乙酯含量提浓至96%以上.     

提高硝酸钾生产中产品结晶率研究

针对复分解法生产硝酸钾存在硝酸钾结晶率较低、成本高的缺点,本文选择了合适的盐析剂L,将盐析结晶技术应用于硝酸钾中试生产,确定了盐析结晶技术制取硝酸钾工艺流程及工艺条件。中试表明,采用盐析结晶技术可以使硝酸钾结晶率提高到78%,提高产量26%,降低蒸汽能耗25%。     

联合制碱法盐析结晶机理初探

根据盐析结晶的机理试验,模拟试验和中间试验结果,初步剖析了联合制碱法的氯化铵盐析结晶机理,提出了扩散传质,接触传质和液膜相变传质过程的机理模型,并指出在实际生产中,应尽可能强化扩散传质,抑制液膜相变过程,以改善盐析氯化铵结晶的质量,强化生产。在此基础上分析了影响盐析结晶生长的各种因素,提出了优化操作的条件。     

盐析萃取应用于乙酸乙酸的提浓

采用盐析萃取应用于稀乙酸为原料制备乙酸乙酯的提浓，对没的萃剂比和含水不同的乙酸乙酯的盐析萃取效果进行了探，经盐析萃取可惭酸乙酯含量提浓至９６％以上。     

盐析法由卤水制备纯碱的新工艺

卤水与碳酸氢铵反应生成碳酸氢钠结晶和氯化铵溶液,碳酸氢钠的结晶率是70%～79%.为了提高碳酸氢钠的结晶率,研究了采用加入盐析剂的方法,通过盐析剂的盐析作用,使碳酸氢钠的溶解度降低,从而更多地结晶析出.实验确定选择高沸点的盐析剂D,使结晶率提高到90%以上.通过正交试验研究,得到盐析法的适宜工艺条件:盐析剂与氯化钠物质的量比为1.0∶ 1.0,反应温度35 ℃,碳酸氢铵与氯化钠的物质的量比为1.0∶1.0,反应时间120 min.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。