利福霉素B氧化生成利福霉素O的工艺研究

对利福霉素B氧化生成利福霉素O的反应体系和操作条件进行了实验研究。通过实验研究发现,NaNO2为适宜的氧化剂,反应介质为甲醇和pH4.62醋酸盐缓冲液的混合体系,适宜反应温度10℃,反应时间1h。在适宜反应条件下,产物收率达到80%,而纯度达到92%以上。     

体系pH值对利福霉素恶嗪环合反应的影响

基于利福平合成反应中间体利福霉素恶嗪的环合反应机制,考察反应体系的pH值对利福霉素恶嗪纯度的影响,以及调节反应体现的pH值对环合反应的温度、时间、合成利福霉素恶嗪和终产品利福平纯度和收率的影响,确定环合反应体系最佳pH值范围在5-7范围时,可以使环合反应的温度从60℃降低到55℃,反应时间由2 h缩短到1.5 h,并可以抑制副反应的发生,提高利福霉素恶嗪和终产品利福平的纯度和收率。     

利福昔明合成工艺的研究

以利福霉素S和2-氨基-4-甲基吡啶为原料,二氯甲烷为溶剂,碘为催化剂,亚硫酸钠为还原剂,合成一种新药利福昔明。结果表明,优化工艺条件为:利福霉素S与催化剂碘的摩尔比为3∶1,2-氨基-4-甲基吡啶与利福霉素S的摩尔比为2.5∶1,反应温度为30℃,反应时间为24 h。在该优化条件下,产品的产率达85.2%。     

橡胶促进剂生产废水的预处理实验研究

采用NaClO催化氧化法对橡胶促进剂生产废水进行预处理,研究pH值、NaClO投加量、反应时间及活性炭投加量对COD去除率的影响。结果表明,NaClO催化氧化法处理该废水的最佳反应条件为:pH值4,NaClO投加量10mL/L,活性炭用量15g/L,反应时间为1h。除胺、酸化及NaClO催化氧化后,COD去除率达66.70%。     

橡胶促进剂生产废水的预处理实验研究

采用NaClO催化氧化法对橡胶促进剂生产废水进行预处理,研究pH值、NaClO投加量、反应时间及活性炭投加量对COD去除率的影响。结果表明,NaClO催化氧化法处理该废水的最佳反应条件为:pH值4,NaClO投加量10mL/L,活性炭用量15g/L,反应时间为1h。除胺、酸化及NaClO催化氧化后,COD去除率达66.70%。     

利福平合成工艺研究

为了提高利福平的产品质量,对目前国内普遍使用的嗪工艺进行了研究与优化。直接以发酵液氧化萃取制得的利福霉素S为原料进行环合反应和缩合反应合成利福平,与以往的利福霉素S钠盐为原料相比,无需利福霉素S钠盐的结晶、分离、干燥及酸化过程,生产工艺更为简单。考察了环合反应温度和时间、缩合反应温度和时间、原料配比及相关的催化剂用量对利福平收率和纯度的影响。得到较优工艺条件为:环合反应温度为55℃,环合反应时间为1.5 h,V(N,N-二羟甲基叔丁胺)∶V(冰醋酸)∶m(抗坏血酸)∶m(利福霉素S)=0.278∶0.014∶0.014∶1.000,缩合反应温度为55℃,缩合反应时间为2 h,V(1-甲基-4-氨基哌嗪)∶m(利福霉素S)=0.463∶1.000,此时,利福平粗品的收率可达86.56%,纯度为92.69%。     

离子液体中TS-1分子筛催化环己烷氧化反应

以离子液体[emim]BF4为反应介质,叔丁基过氧化氢(TBHP)为氧化剂,TS-1分子筛为催化剂,进行了环己烷选择性氧化反应研究.考察了氧化剂与环己烷物质的量比、反应时间、反应温度及离子液体/催化剂体系循环使用对环己烷氧化反应的影响.实验结果表明,在TBHP/环己烷物质的量比为2,反应温度为90 ℃,反应时间为18 h时,环己烷的转化率为13.2%,目的产物环己酮与环己醇的选择率高达97.6%.离子液体/催化剂体系循环使用4次后环己烷的转化率及氧化产物的收率略有降低.     

利福昔明合成工艺的研究

以利福霉素S和2-氨基-4-甲基吡啶为原料,二氯甲烷为溶剂,碘为催化剂,亚硫酸钠为还原剂,合成一种新药利福昔明。结果表明,优化工艺条件为：利福霉素S与催化剂碘的摩尔比为3∶1,2-氨基-4-甲基吡啶与利福霉素S的摩尔比为2.5∶1,反应温度为30℃,反应时间为24 h。在该优化条件下,产品的产率达85.2%。     

利福昔明的合成研究

以利福霉素S、液溴、2-氨基-4-甲基吡啶、抗坏血酸(VC)为主要原料,经过溴化、环合、还原三个步骤制备了利福昔明。结果表明,最优工艺条件为:溴化反应采用乙醇和水溶剂体系,利福霉素S与溴的摩尔比为1∶1.2;环合反应中3-Br-利福霉素S与2-氨基-4-甲基吡啶的摩尔比为1∶1.6,反应温度为63℃。在该优化条件下,产品总收率达85.1%。     

双膜分离技术在利福霉素O提取中的应用

根据利福霉素O工艺过程中利福霉素B及利福霉素O的理化性质,两次利用无机陶瓷膜在利福霉素O生产中使用,确定了最佳工艺参数,优化了传统工艺,提高了产品收率及质量,同时新工艺大大地降低了溶媒消耗,节约生产成本。     

利福霉素噁嗪稳定性的研究

研究考察了利福平合成反应中间体———利福霉素嗪在不同温度下的稳定性,确定了环合反应的温度及时间。考察了浓缩过程中嗪的稳定性,确定了利福平合成工艺的浓缩过程温度为85°C、时间应少于100min。     

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.