2-硝基-1,3-苯二甲醚的合成

采用间苯二酚为原料,经过磺化、硝化、水解合成2-硝基-1,3-苯二酚,再用硫酸二甲酯进行甲基化,得到2-硝基-1,3-苯二甲醚。重点讨论了2-硝基1,3-苯二酚及其甲醚化工艺条件,结果表明,使用质量分数20%发烟硫酸可使1,3-苯二酚全部二磺化从而使2-硝基1,3-苯二酚收率增至63.5%,色谱纯度达98.5%以上;在反应温度80℃,反应时间4 h,n(M e2SO4)∶n(2-硝基1,3-苯二酚)=2.2∶1.0时,2-硝基-1,3-苯二酚甲基化收率高达75.6%。     

取代1,3-二苯基-1,3-丙二酮的合成与抗氧化性能

以取代芳酮和取代芳酯为原料,经克莱森反应合成了5个取代1,3-二苯基-1,3-丙二酮。采用正交实验优化1,3-二(4-甲氧基苯基)-1,3-丙二酮较佳的工艺条件:以甲苯为溶剂,NaNH2作催化剂,n(对甲氧基苯乙酮)∶n(对甲氧基苯甲酸甲酯)∶n(氨基钠)=1∶4∶5,微波辐射功率320 W,反应时间45 min,收率为72.1%。合成的产物结构经IR与1HNMR光谱进行了结构表征,用HPLC测定其含量。对UV光谱有良好的吸收及对猪油有较好的抗氧化作用。     

取代1,3-二苯基-1,3-丙二酮的合成与抗氧化性能研究

以取代芳酮和取代芳酯经克莱森反应合成了5个取代1,3-二苯基-1,3-丙二酮。采用4因素3水平正交试验优化1,3-二(4-甲氧苯基)-1,3-丙二酮较佳的工艺条件：以甲苯为溶剂,NaNH2作催化剂,n(对甲氧基苯乙酮)：n(对甲氧基苯甲酸甲酯)：n(氨基钠)=1:4:5,微波辐射功率320W,反应时间45min,收率为72.1%。合成的产物结构经IR与1HNMR光谱进行结构表征,用HPLC测定含量。对UV光谱有良好的吸收及对猪油有较好的抗氧化作用     

1,3-二甲基-2-咪唑啉酮的制备

以乙二胺、尿素、甲醛和甲酸为原料,经过环化和甲基化反应制得目标产物1,3-二甲基-2-咪唑啉酮(1,3-DMI)。通过红外、核磁对其结构进行了确证。考察了溶剂、原料浓度、原料摩尔比、反应温度和时间、催化剂对制备(1,3-DMI)收率的影响。较佳工艺条件为:制备2-咪唑啉酮时,以水-乙二醇混合作溶剂;制备1,3-DMI时,甲醛(36%)∶甲酸(85%)摩尔比为1∶2.8,反应温度95~100℃,反应时间16 h,氯化亚铜和三乙胺作催化剂,用量分别是2-咪唑啉酮摩尔数的1.0%。总收率达到71%,纯度为98.5%。     

多聚甲醛制备2-异丙基-2-异戊基-1,3-丙二醇

使用多聚甲醛作原料制备了2-异丙基-2-异戊基-1,3-丙二醇(PPPO)。考察了催化剂、反应温度、反应时间对PPPO收率的影响。结果表明,最佳工艺条件为n(己醛)∶n(单体甲醛)=1∶3.1,20℃滴加30%氢氧化钠溶液,2 h加完,40℃反应8 h。在此条件下,PPPO收率为83.4%。     

2,2-二氟丙烷-1,3-二胺的合成

该文经氟化、酰胺化和还原3步反应合成了2,2-二氟丙烷-1,3-二胺(DFPDA)。以丙二酸二乙酯为基本原料,首先经选择性氟化剂1-氯甲基-4-氟-1,4-二氮双环[2.2.2]辛烷双氟硼酸盐(Selectfluor)氟化得第一中间体2,2-二氟丙二酸二乙酯(DFDEM),DFDEM再经氨水酰胺化反应得到第二中间体2,2-二氟丙二酰胺(DFMA),最后以硼烷为还原剂,将中间体DFMA还原得到最终产品2,2-二氟丙烷-1,3-二胺(DFPDA),总收率最高可达45%。考察了3步反应的工艺条件对产品收率的影响,结果表明,较理想的反应条件为:氟化反应温度0℃,n(丙二酸二乙酯):n(氢化钠):n(Selectfluor)=1:3:3,氟化反应收率达58.18%;酰胺化反应8 h,n(氨水):n(DFDEM)=5:1,酰胺化反应收率可达96%以上;在65℃还原反应3～4 h,n(DFMA):n(BH3)=1:7.5,还原反应收率达91.1%。用IR、1HNMR和GC-MS分析了每个产物的化学结构。     

2-甲基-1，3-环戊二酮的合成

以丁二酸和丙酰氯为原料,无水A lC l3为催化剂,合成2-甲基-1,3-环戊二酮,并对工艺条件进行了优化。最佳条件为:在氮气作用下,n(丁二酸):n(丙酰氯):n(氯化铝)=1:3:3,反应温度100℃,回流时间2h,产品收率为58.9%。用红外光谱确定了产品结构。     

1-甲基-2,4,5-三硝基咪唑(MTNI)的合成

以4-硝基咪唑为原料,经硝化、热重排、甲基化等反应合成1-甲基-2,4,5-三硝基咪唑(MTNI),总收率19.4%,纯度>98%,经红外光谱、核磁共振、元素分析等方法表征其结构。研究了反应温度、反应时间等因素对1-甲基-2,4-二硝基咪唑(MDNI)合成及收率的影响,得到了较优的工艺条件:n(2,4-二硝基咪唑)∶n(碘甲烷)=5∶9,反应温度40~45℃,反应时间8h。对硝化反应条件进行了研究,确定了适宜反应时间为1h,反应温度为95℃。     

甘油合成1,3-丙二醇

以甘油为原料,经过氯代、氧化、克莱门森还原、水解4步反应,最终合成1,3-丙二醇,并用红外光谱仪和质谱仪对目标产物进行结构确定。从反应物摩尔比、反应温度、反应溶剂等优化了反应条件。最优反应条件为:氯代反应:温度120℃;氧化反应:温度23～27℃,n(1,3-二氯-2-丙醇)∶n(重铬酸钠)=1.8∶1,反应溶剂用量:1 mL水溶解1.4 g 1,3-二氯-2-丙醇;克莱门森还原反应:n(1,3-二氯丙酮)∶n(锌)=1∶1.2,水作反应溶剂最佳,在该条件下,1,3-丙二醇总产率可达37.1%。     

改性活性炭催化合成苯乙酮1,3-丙二醇缩酮工艺研究

采用活性炭负载Al2(SO4)3作为催化剂(Al2(SO4)3改性活性炭);以苯乙酮和1,3-丙二醇为原料合成苯乙酮1,3-丙二醇缩酮.考察了Al2(SO4)3。改性活性炭催化剂用量、原料配比、回流时间和带水剂用量对此反应工艺条件的影响.最佳的反应工艺条件为Al2(SO4)3改性活性炭用量为苯乙酮用量的6.67%,n(苯乙酮)∶n(1,3-丙二醇)=1∶1.1,带水剂用量为15 mL,回流时间为5 h,在此最佳反应条件下苯乙酮1,3-丙二醇缩酮的收率为61.15%,经前馏分循环使用可使收率提高到65.64%,产品的纯度为98.1%。Al2(SO4)3。改性活性炭催化剂的制备简单,催化活性好,而且重复利用后的产率并不下降,其后处理简便,无三废污染,符合环保、绿色催化的发展的趋势。     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.