尿素包合法富集分离花生四烯酸的工艺研究

为提高尿素包合法富集花生四烯酸(AA)效率,研究了降温速度、甲醇用量、尿酯比及结晶温度对花生四烯酸(AA)晶体大小、收率及纯度的影响。结果表明,当结晶温度为-7℃,降温速度为10℃/h,m(脂肪酸甲酯)∶m(尿素):v(甲醇)为1 g∶2 g∶20 mL时,AA生成大颗粒晶体。AA的质量分数w(AA)=87.0%,收率为88.7%。杂质主要为亚麻酸(w=9.21%)。产品总不饱和脂肪酸质量分数大于99%。     

十二烷二酸二甲酯粗品的精馏-结晶纯化

采用精馏-结晶法分离以环己酮为原料合成十二烷二酸二甲酯的粗品,探讨了各种工艺条件对结晶分离的影响.结果表明:结晶分离最佳工艺条件为:m(精馏双酯)∶m(甲醇)=1∶0.8～1.5,结晶溶液始温30℃左右,终温5～8 ℃,降温速率2～3 ℃/min,搅拌速度5～25 r/min;结晶母液中甲醇可通过蒸馏回收循环使用,残留双酯返回精馏系统.所得十二烷二酸二甲酯的纯度可达99.5%以上,符合医药中间体、香料等行业的使用要求.     

尿素包合法纯化小桐子油多不饱和脂肪酸的工艺

研究了尿素包合法纯化小桐子油脂中多不饱和脂肪酸(PUFAs)的工艺条件.考察了溶剂种类、不饱和脂肪酸/尿素/甲醇质量比、包合温度和降温方式对PUFAs纯化效果的影响.3种溶剂中,甲醇对PUFAs的纯化效果最好.当UFAs/尿素质量比为1∶1、1∶1.5、1∶2、1∶2.5时,PUFAs纯度不断提高,分别为69.38%、...     

软钾镁矾在乙醇-水和甲醇-水混合溶剂中的结晶特性

采用湿渣法系统地测定了软钾镁矾在乙醇-水和甲醇-水混合溶剂中的相平衡数据,利用电导率法确定了其在水中的超溶解度及结晶介稳区,考察了温度、搅拌速率和降温速率对介稳区的影响. 结果表明,35℃下,软钾镁矾在两混合溶剂中的溶解度随其中乙醇和甲醇比例增大而减小,当乙醇:水或甲醇:水为1:1(j)时,软钾镁矾溶解度接近0,且相同配比的混合溶剂中,甲醇-水溶液中K2SO4的结晶区比乙醇-水溶液中大;在实验范围内,软钾镁矾的介稳区宽度随降温速率由15℃/h增至35℃/h而由0.40%增至1.48%(w,以软钾镁矾计,下同),随搅拌速率由250 r/min增至460 r/min而由1.54%降至1.04%,随温度由25℃升至35℃而由1.61%降至1.24%.     

苯酚焦油中提取对枯基苯酚工艺

苯酚焦油是异丙苯法生产苯酚过程中的副产物,其中含有的对枯基苯酚附加值较高。通过先将苯酚焦油蒸馏,得到较高浓度的对枯基苯酚,再采用两步结晶方法得到高纯度对枯基苯酚产品。研究结果表明,控制第一步结晶溶剂比m(正己烷)∶m(对枯基苯酚)=5∶1、溶解温度为43℃、降温速度为2℃/h、结晶终温度为24℃;重结晶溶剂比m(正己烷)∶m(对枯基苯酚)=3∶1、溶解温度为55℃、降温速度为2℃/h、结晶终温为25℃,得到对枯基苯酚产品纯度达到99.56%。工艺路线简单,实现了对枯基苯酚清洁生产。     

湿法磷酸合成磷酸脲的工艺研究

以湿法磷酸为原料直接合成磷酸脲,研究降温速率、搅拌速度、反应温度、反应时间、磷酸与尿素配比、结晶时间等工艺条件对磷酸脲收率的影响。得到最佳工艺条件为:降温速率为8℃/h,搅拌速度200 r/min,反应温度75℃,反应时间80 min,尿素与磷酸物质的量之比为1.05,结晶时间8 h,在此条件下磷酸脲的收率可达到63.24%。     

碱性介质多元体系中钒酸钠结晶分离

测定了NaOH-NaNO_3-NO_3VO_4-Na_2CrO_4-H_2O五元体系各盐在碱中的相平衡浓度,根据所得数据对该体系中的Na_3VO_4进行了冷却结晶分离.通过研究NaOH浓度、NaNO_3浓度、结晶终点温度、降温速度、搅拌速度、晶种对钒酸钠结晶分离的影响,得到的最优实验条件为:结晶液中NaOH浓度200~250g/L,NaN0_3浓度200g/L左右,搅拌转速200r/min,80~40℃自然降温,添加晶种量1%(ω),该条件下Na_3VO_4结晶率为61%,晶体纯度可达95%,且晶体颗粒人(147μm),沉降分离速度快(10min).     

过氧化尿素合成工艺及稳定性研究

以工业级尿素和双氧水为原料,采用正交实验合成过氧化尿素(UP),研究了原料摩尔比、反应时间、反应温度、结晶温度对产品活性氧含量、收率和稳定性的影响,探讨了不同稳定剂及用量对产品稳定性的影响。结果表明,以收率为指标的优化工艺条件为:双氧水与尿素摩尔比1.3∶1,反应温度35℃,反应时间35 min,结晶温度5℃;以稳定性为指标的优化工艺条件为反应时间35 min,结晶温度0℃,双氧水与尿素摩尔比1.4∶1,反应温度35℃。稳定剂的添加能提高过氧化尿素产品稳定性,其中以乙二胺四乙酸二钠、酒石酸、磷酸二氢钠效果较好,用量为尿素质量的0.8%~1.0%,产品稳定度达97%以上。     

KOH介质多元体系中铬酸钾与钒酸钾的高效结晶分离

测定了KOH-K3VO4-H2O体系的溶解度,结合KOH-K2CrO4-H2O体系的溶解度变化规律,研究了KOH-K2CrO4-K3VO4-H2O四元体系中蒸发结晶分离K2CrO4和冷却结晶分离K3VO4的方法. 针对钒渣钾系亚熔盐分解获得的溶出液组成,研究了该体系中K2CrO4和K3VO4结晶分离工艺参数对分离效果的影响. 结果表明,将溶出液蒸发至KOH浓度为630~670 g/L进行K2CrO4分离,K2CrO4结晶率达90%以上,晶体纯度达95%以上;将分离K2CrO4后的结晶母液继续蒸发至KOH浓度为800~850 g/L,从80℃到40℃自然降温,在搅拌速度200 r/min、晶种添加量2%(w)的优化结晶条件下,K3VO4结晶率为60%以上,晶体纯度达90%以上. 分离K2CrO4和K3VO4后的溶液返回钒渣亚熔盐分解反应过程循环使用.     

铵光卤石复盐的制备及结晶动力学研究

用盐湖卤水提钾后的水氯镁石溶液和生产镁砂副产的氯化铵溶液为原料,研究了制备铵光卤石的工艺条件.当溶液中氯化镁和氯化铵的物质的量比为1∶1时,在溶液pH为6.0、反应温度为85 ℃、搅拌速度为500 r/min、加热蒸发时间为1 h的条件下,在7 ℃冷却结晶4 h,然后过滤烘干,铵光卤石一次结晶产率为60%,二次结晶产率高达80%.测定了铵光卤石在水溶液中不同温度下的溶解度,利用10,20 ℃的溶解度和动力学参数建立了铵光卤石结晶动力学方程.动力学方程证明铵光卤石的低温结晶受单核结晶生长控制.     

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

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。     

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.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。