L-抗坏血酸-2-聚磷酸酯的合成

研究了L 抗坏血酸与磷酸化试剂在水介质中制备L 抗坏血酸 2 一聚磷酸酯和L 抗坏血酸 2 三聚磷酸酯 ,当n(L 抗坏血酸 )∶n(三偏磷酸钠 )∶n(催化剂 ) =1 .0 0 0∶1 2 0 0∶0 1 50、溶液pH值为 8时 ,L 抗坏血酸 2 三聚磷酸酯的收率为 71 34% ,Vc效价为 32 1 0 %。作为饲料添加剂使用 ,可同时给动物补充钙和磷。     

L-抗坏血酸-2-三聚磷酸酯的制备及其热稳定性研究

以Vc及三偏磷酸钠为原料,一定温度条件下在水介质中进行酯化反应,一步制得目的产物L-抗坏血酸-2-三聚磷酸酯(AsTP);采用紫外分光光度法对产品定量分析,最后对制备的AsTP与Vc的热稳定性作了对比研究。试验结果表明,制备AsTP的最佳制备工艺条件为:溶液中Vc初始质量分数为10%,三偏磷酸钠与Vc物质的量比为1.2,反应温度为50℃,反应时间为50min,溶液pH值为10,相应Vc-2-三聚磷酸钠转化率可达84.45%。在80℃高温下将相同浓度的Vc与Vc-2-三聚磷酸钠在相同搅拌速率条件下处理90min,处理后Vc有效率仅有2.9%,大部分Vc已经因分解而损失,而AsTP处理后有效率为91.01%,表明其热稳定性比Vc高得多。     

L-抗坏血酸多聚磷酸酯的合成研究

以L-抗坏血酸为原料,三偏磷酸钠为磷酸化试剂,氯化钙为催化剂,在极性水溶液体系中发生酯化反应生成L-抗坏血酸多聚磷酸酯.通过单因素及正交实验,获得了适宜的反应条件:反应温度为35℃,L-抗坏血酸与三偏磷酸钠的摩尔比为1:1.3,L-抗坏血酸与氯化钙的摩尔配比为1:0.15,反廊溶液pH为9,在该反应条件下,L-抗坏血酸多聚磷酸酯收率为76.58%.     

维生素C磷酸酯的工艺优化研究

通过L-抗坏血酸与丙酮反应生成中间产物5,6-O-异丙叉-L-抗坏血酸(IPAA),再与三氯氧磷在水和吡啶混合体系中进行磷酰化反应,得L-抗坏血酸-2-磷酸酯镁(AP-Mg)。利用正交试验法得到制备L-抗坏血酸-2-磷酸酯镁的最佳工艺条件为:POCl3与IPAA的摩尔比为1.8∶1,吡啶浓度2.6 mol/L,pH=12.5时,产率86.75%,纯度92.30%。     

L-抗坏血酸-2-磷酸酯镁的合成与纯化

L-抗坏血酸与丙酮反应生成5，6-0-异丙叉-L-抗坏皿酸（IAA)，再与三氯氧磷进行磷酰化反应．往反应混合液中加入等体积的95％醇，再加入CaCl2溶液，以沉淀出L-抗坏血酸-2-磷酸酯钙晶体；把制得的钙盐溶解在搅拌的阳离子交换树脂的悬浮液中，然后通过阳离子交换柱以除去金属离子．在pH=9下转化为L-抗坏血酸-2-磷酸酯镁，收率为68．2％(以IAA计)，     

L-2-氯丙酸的合成工艺研究

以L-2-氨基丙酸为起始原料,经过重氮化、氯化、萃取、减压精馏步骤制得手性2-氯丙酸,并考察了原料配比、反应温度、酸浓度对反应的影响。最佳工艺条件为:n(L-丙氨酸)∶n(亚硝酸钠)为1∶1.6,n(碳酸钠)∶n(L-丙氨酸)为1.2∶1,盐酸浓度为25%,反应温度为5℃,反应时间为8 h,在该条件下产品收率达72.0%,e.e.%值为97.6%~98.3%,比旋光度-14.6°。     

紫外光谱法研究L-抗坏血酸-2-多聚磷酸酯的稳定性

探讨了影响L-抗坏血酸-2-多聚磷酸酯稳定性的主要因素,利用紫外光谱法研究了酸碱、温度和离子等对其稳定性的影响.     

酰氯法合成L-抗坏血酸苯甲酸酯工艺的改进

在N,N-二甲基乙酰胺(DMAc)中,苯甲酸与SOCl2反应生成的苯甲酰氯不经分离,继续与L-抗坏血酸反应得到L-抗坏血酸苯甲酸酯。考察了酰氯化反应时间、成酯反应时间、反应溶剂和物料比对反应收率的影响,结果表明,以10mL DMAc为溶剂,0℃下酰氯化反应2h后,接着在25℃下成酯化反应10h,苯甲酸10mmol,n(苯甲酸)∶n(SOCl2)∶n(L-抗坏血酸)=1.0∶1.1∶1.6,反应收率为62.8%。产物结构经1 H NMR、13C NMR、MS和IR确认。     

L-抗坏血酸-2-磷酸酯镁的制备研究

L-抗坏血酸-2-磷酸酯镁是一种稳定的维生素C衍生物，是维生素C转化的较好途径。改进了基团保护法的催化剂并探讨反应条件对反应的影响。     

基团保护法合成维生素C磷酸酯镁

对基团保护法合成L-抗坏血酸-2-磷酸酯镁进行了研究,分析了各反应因素对反应结果的影响,确定了最佳合成条件.     

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。