L-苹果酸与醇的酯化反应研究

通过气相色谱-质谱法、液相色谱法研究了浓硫酸、盐酸、无水氯化镍、无水氯化钴、分子筛、三氧化钼、三氧化钨催化苹果酸和乙醇酯化反应的催化活性及产物组成。研究了不同催化条件下苹果酸与乙醇的酯化反应;通过单因素实验研究了催化剂用量、苹果酸与乙醇的质量比、溶剂及溶剂用量对苹果酸转化率及苹果酸二乙酯的产率的影响。实验结果表明,L-苹果酸1. 34 g、无水乙醇4. 6 g,氧化钼0. 25 g,溶剂甲苯用量为5mL,回流反应,苹果酸二乙酯的产率达38. 5%。     

乙醛缩二乙醇的制备

以乙醇和乙醛为原料制备乙醛缩二乙醇影响产率的主要因素有：原料配比、反应温度、吸水剂量、反应时间、催化剂通入时间。利用正交试验的方法找出优化方案，通过单因素实验确定出最佳反应条件为：无水乙醇与新蒸乙醛摩尔比为2．4：1．0，3℃～5℃，硅胶用量为34g(对lmol晰蒸乙醛而言)，反应55min，催化剂通入 13min。产率可达90％以上。     

一种溴乙醛缩二乙醇的合成方法

<正>本发明公开了一种溴乙醛缩二乙醇的合成方法,由下述工艺步骤组成:1催化溴化反应:将原料三聚乙醛、铜催化剂、浓硫酸以及无水乙醇搅拌溶解,用冰盐浴冷却,再向反应釜中缓慢滴加单质溴,并在-5~0℃反应1-1.5h,得到溴乙醛的乙醇溶液;2缩醛化反应:向上步得到的溴乙醛乙醇溶液中投     

一种溴乙醛缩二乙醇的合成方法

本发明公开了一种溴乙醛缩二乙醇的合成方法,由下述工艺步骤组成:(1)催化溴化反应:将原料三聚乙醛、铜催化剂、浓硫酸以及无水乙醇搅拌溶解,用冰盐浴冷却,再向反应釜中缓慢滴加单质溴,并在-5℃~0℃反应1h~1.5h,得到溴乙醛的乙醇溶液;(2)缩醛化反应:向上步得到的溴乙醛乙醇溶液中投入无机脱水剂,加热升温至35℃~40℃,保温反应5h~6h后,再加入冰水,反应15min~20min,加入碳酸钠中和反应液,搅拌,静置分层,分出有机层,水层用二氯乙烷提取两次,合并有机相,先减压蒸馏回收溶剂,再减压分馏,收集65℃~68℃馏分,即得高纯度的溴乙醛缩二乙醇;本发明原料易得,反应步骤少,成本低,产品纯度高,质量稳定。     

全氟磺酸树脂催化合成乙醛缩二乙醇的研究

以乙醛和无水乙醇为原料,废弃的全氟磺酸树脂为催化剂合成乙醛缩二乙醇缩醛,对影响反应的因素进行研究。当醇醛摩尔比为2.4∶1、催化剂用量为3﹪、分子筛作为吸水剂,在3⁵℃反应60min,最高产率达到90.1%。该催化剂绿色环保且易于回收,且重复使用六次以上产率仍可达到89.1%以上。     

β-萘乙醚的微波合成研究

研究了以β 萘酚、无水乙醇为原料,浓硫酸为催化剂,采用微波辐射方法合成β 萘乙醚,并探索了反应条件对产物产率的影响。实验结果表明,在反应物用量β 萘酚3.6g(0.025mol),无水乙醇30mL,浓硫酸7mL,微波辐射功率260W,微波辐射时间40min条件下反应,产率可达71%以上。与常规加热合成方法比较,本方法反应时间大大缩短(由6h缩至40min),产率较高(从60%增至71%)。     

卤代乙醛缩二乙醇的合成

以醋酸乙烯酯、乙醇、氯气为原料,采用一锅煮方法合成氯乙醛缩二乙醇,同时用正交实验法优化了关键步骤氯乙醛和乙醇的缩合反应条件,得到优化条件为:醋酸乙烯酯与乙醇的比为1:5,缩合反应时间3h,缩合反应温度60℃,中和到pH值为6,此条件下产品收率达83%.并且在相同的实验条件下对其它卤代乙醛缩二醇的合成进行了初步的探讨,产品收率在60～80%之间.     

臭氧-乙醇法制取甲醛

<正> 用臭氧与无水乙醇反应制取甲醛未见有报道。经验研究表明在50～85℃时,臭氧与乙醇能发生反应;在反应中,臭氧既是催化剂又是氧化剂。臭氧促进乙醇脱水作用比用浓硫酸或无水三氯化铝降低2.45～5倍的反应温度,为此我们拟出“乙醇→乙烯→臭氧化合物→甲醛”的合成新路线。     

α-甲基-缩二乙醇酸二乙酯的合成

采用重氮乙酸乙酯(EDA)与乳酸乙酯在无水硫酸铜催化下进行O-H插入反应合成α-甲基-缩二乙醇酸二乙酯。讨论了反应时间,催化剂用量,反应温度和物料比例对插入反应收率的影响,在优化反应条件下产率为58.8%。产品纯度大于98%。     

RuCl3一步催化氧化液相乙醇合成1,1-二乙氧基乙烷

首先考察了不同金属卤化物对乙醇一步液相氧化合成1,1-二乙氧基乙烷(DEE)的催化性能。结果表明,RuCl_3催化性能最好。然后考察了反应条件的影响,结果表明,以50 mL无水乙醇(0.86 mol)为反应物时,最佳催化反应条件为:反应温度120℃、氧气压力2MPa、反应时间3h、催化剂用量0.004%(以乙醇的物质的量为基准,下同)、搅拌速度600 r/min,此时乙醇转化率达到38.2%,DEE选择性达到78.9%。并且发现,Ru~(3+)不但对乙醇氧化成乙醛具有较高的催化活性,同时RuCl_3是一种温和的路易斯酸,可以较好地催化乙醇与乙醛的缩合反应。最后对RuCl_3催化剂的重复使用性进行了考察,催化剂重复使用20次后,依然有较高的催化活性。     

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。