乙醇-水混合溶剂中5′-尿苷酸二钠的结晶介稳区

采用双光路激光法,在293.2～318.2 K温度范围内,研究了5′-尿苷酸二钠在不同比例乙醇-水混合溶剂中的溶解与超溶解特性,得到了5′-尿苷酸二钠的结晶介稳区。采用λh方程关联了4个体系的溶解度数据,进而分别求得各体系下的混合焓和结晶焓。同时,探讨了搅拌转速、pH值和钠离子浓度对结晶介稳区的影响。实验结果表明,与温度相比较,乙醇质量分数是影响溶解度和超溶解度的主要因素;随乙醇质量分数的增大,5′-尿苷酸二钠的溶解度和超溶解度显著减小;在相同条件下,溶液pH值和钠离子浓度的升高,以及搅拌转速的降低均会增大5′-尿苷酸二钠结晶介稳区的宽度。     

乙醇-水溶剂中5'-尿苷酸二钠溶解度测定与关联

采用内置双光路激光检测器,在293.2-318.2 K温度范围内,测定了5'-尿苷酸二钠在纯水及不同乙醇-水混合溶剂中的溶解度.分别用R-K方程、λh方程和Wilson方程3种溶解度模型,采用最小二乘法关联实验数据,并对比不同溶解度模型.结果表明,在乙醇质量分数为0-0.65区间内,5'-尿苷酸二钠溶解度随着温度的升高而增大,随乙醇质量分数的增大而显著减小,λh方程对5'-尿苷酸二钠溶解度关联效果最好.将λ,h表达为乙醇质量分数的函数,并用于内插计算,精度满足工程要求.     

乙醇-水溶剂中5′-尿苷酸二钠溶解度测定与关联

采用内置双光路激光检测器,在293.2—318.2 K温度范围内,测定了5′-尿苷酸二钠在纯水及不同乙醇-水混合溶剂中的溶解度。分别用R-K方程、λh方程和Wilson方程3种溶解度模型,采用最小二乘法关联实验数据,并对比不同溶解度模型。结果表明,在乙醇质量分数为0—0.65区间内,5′-尿苷酸二钠溶解度随着温度的升高而增大,随乙醇质量分数的增大而显著减小,λh方程对5′-尿苷酸二钠溶解度关联效果最好。将λ,h表达为乙醇质量分数的函数,并用于内插计算,精度满足工程要求。     

汽液平衡盐效应的分子热力学──乙醇-水-1-1型电解质系统恒压汽液平衡盐效应参数的计算

测定了6个乙醇-水-1-1型电解质系统（LiCl、LiBr、NaBr、NaAc、KCl、KI）恒压（100.8kPa）条件下的汽液平衡盐效应参数.在Pierotti定标粒子溶液理论基础上提出非电解质浓度任意变化条件下含盐双液系汽液平衡盐效应参数的计算方法.硬球作用项采用Masterton-Lee方程计算，软球作用项采用胡英等人建议的分子热力学模型计算．对于乙醇-水极性混合溶剂系统，离子-中心分子的碰撞直径考虑离子溶剂化的影响，以离子的溶剂化系数为可调参数，拟合出混合溶剂的局部介电常数与乙醇摩尔分数的关联方程．预测结果表明，在很大液相浓度范围（X_1=0.143～0.700）内14个乙醇-水-1-1型电解质系统52个盐效应参数的平均相对误差为7.76％     

不同质量分数乙醇、乙酸钠溶液对双乙酸钠结晶过程影响

为提高双乙酸钠(SDA)的产品质量,考察了温度、溶剂组成、乙酸钠含量等条件对SDA溶解性的影响,采用动态法测定了SDA在不同质量分数乙醇-水、乙酸钠-水混合溶剂中的溶解度,并测定了SDA在纯水和质量分数为0.799 6(w1=0.799 6)的乙醇溶液中的介稳区。结果表明,SDA易溶于水,微溶于乙醇,随乙醇质量分数增加,SDA溶解度降低愈加显著,且在w1=0.799 6的乙醇溶液中降低最为明显;随产物中乙酸钠含量增加,SDA溶解度逐渐减小,且在质量分数为0.083 2乙酸钠溶液中降低幅度最大;在300~315 K范围内,w1=0.799 6的乙醇溶液对SDA和乙酸钠有明显的分离效果;SDA的介稳区宽度在纯水中随温度升高逐渐变窄,而在w1=0.799 6的乙醇溶液中受温度影响变化小,且介稳区宽度较纯水中窄。因此,在SDA结晶中,可采用w1=0.799 6的乙醇溶液结晶分离SDA,且过饱和浓度需控制在介稳区内。     

汽液平衡盐效应的分子热力学──乙醇-水-1-1型电解质系统恒压汽液平衡盐效应参数的计算

测定了6个乙醇-水-1-1型电解质系统（LiCl、LiBr、NaBr、NaAc、KCl、KI）恒压（100.8kPa）条件下的汽液平衡盐效应参数.在Pierotti定标粒子溶液理论基础上提出非电解质浓度任意变化条件下含盐双液系汽液平衡盐效应参数的计算方法.硬球作用项采用Masterton-Lee方程计算，软球作用项采用胡英等人建议的分子热力学模型计算．对于乙醇-水极性混合溶剂系统，离子-中心分子的碰撞直径考虑离子溶剂化的影响，以离子的溶剂化系数为可调参数，拟合出混合溶剂的局部介电常数与乙醇摩尔分数的关联方程．预测结果表明，在很大液相浓度范围（X_1=0.143～0.700）内14个乙醇-水-1-1型电解质系统52个盐效应参数的平均相对误差为7.76％     

布洛芬-烟酰胺共晶制备及其溶解度测定

采用乙醇-水混合溶剂,对布洛芬-烟酰胺共晶的溶液结晶法制备过程进行了研究,制备样品的PXRD和DSC表征结果证明了通过溶液结晶法大规模制备布洛芬 烟酰胺共晶的可行性。制备过程研究结果表明,当混合溶剂中乙醇与水的体积配比为1.82～7.11时,可以制备出布洛芬-烟酰胺共晶;而且随着乙醇与水体积配比的增大,共晶收率呈现先增大再减小的趋势,当体积配比为2.76时,共晶收率达到最大值(76.31%)。还在不同温度下测定了布洛芬-烟酰胺共晶在不同体积配比乙醇-水混合溶剂中的溶解度,结果表明随着温度和乙醇体积比例的升高,布洛芬-烟酰胺共晶的溶解度增大,最后用 Apelblat方程对溶解度数据进行拟合。     

葡萄糖在超/亚临界醇-水二元混合溶剂中的稳定性研究

以降低对反应条件的要求、减少可发酵糖的降解为出发点,在压力10 MPa,温度165～315℃范围内,研究了葡萄糖在水及在物质的量分数为0.6的甲醇-水、乙醇-水、异丙醇-水二元混合溶剂中的稳定性。结果表明:相同反应条件下,葡萄糖在乙醇-水二元混合溶剂中的稳定性高于在水及甲醇-水二元混合溶剂中的稳定性,而与在异丙醇-水二元混合溶剂中的稳定性相差不大。且在本研究涉及的混合溶剂中,反应温度越高,葡萄糖的稳定性越差。鉴于葡萄糖在乙醇-水二元混合溶剂中有较好的的稳定性,在乙醇物质的量分数0～0.85,温度165～315℃,压力8～16 MPa,停留时间0.57～2.1 min范围内,对乙醇-水二元混合溶剂中葡萄糖的稳定性做了进一步研究。结果表明:葡萄糖的稳定性随乙醇物质的量分数的增加而增加;压力对葡萄糖的稳定性影响不大;停留时间越短,葡萄糖的稳定性越好,本研究条件范围内,乙醇的物质的量分数0.85,停留时间0.57 min, 温度低于250℃葡萄糖稳定性相对较好。     

人造麝香DDHI重结晶的研究

测定了人造麝香DDHI在不同质量分数的乙醇水溶液中的溶解度 ,并用重结晶的方法提纯DDHI,适宜的工艺条件为 :用质量分数为 80 %的乙醇水溶液作为溶剂 ,将液态DDHI溶于 6 0℃的溶剂中 ,缓慢冷却至 2 0℃进行重结晶 ,溶液的pH =7,乙醇水溶液与DDHI的质量比为 2 3～2 6 ,进行二至三次重结晶可得到质量分数大于 99 5 %的DDHI     

四氢咔唑酮离解常数的光度法测定

研究了四氢咔唑酮在不同比例的乙醇.水混合溶剂中及不同酸度下的吸收光谱,提出了采用紫外分光光度法测定四氢咔唑酮在水中离解常数的方法.试验证明:在不同比例的乙醇.水混合溶剂中,四氢咔唑酮的离解常数与乙醇的体积分数存在良好的线性关系,通过外推至乙醇含量为零,可求得在实验条件下四氢咔唑酮在水溶液中的离解常数pKb为14.04.     

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.     

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.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。