相转移催化法合成十二烷基缩水甘油醚

以十二醇和二氯丙醇为原料,用相转移催化剂直接合成了十二烷基缩水甘油醚。考察了催化剂种类、原料摩尔比、反应时间和反应温度对十二烷基缩水甘油醚收率的影响。结果表明,以四丁基溴化铵为催化剂,甲苯为溶剂,n(十二醇)∶n(二氯丙醇)=1∶1.60,反应温度50℃,反应时间4 h,十二烷基缩水甘油醚收率可达73.2%。用IR、1HNMR对产物结构进行了表征,采用测定产品环氧值的方法来计算十二烷基缩水甘油醚的收率。     

3-十六烷氧基-2-羟基丙基三甲基氯化铵的合成及性质研究

以十六醇、环氧氯丙烷(EPIC)与三甲胺盐酸盐合成了阳离子表面活性剂3-十六烷氧基-2-羟基丙基三甲基氯化铵(HPAC)。中间体十六烷基缩水甘油醚最佳合成条件:n(十六醇)∶n(EPIC)=1∶1.8,反应时间4 h,温度50℃,NaOH的浓度为50%,四丁基溴化铵作催化剂;HPAC最佳合成条件:n(十六烷氧基缩水甘油醚)∶n(三甲胺盐酸盐)=1∶1,温度30℃,反应3 h,HPAC的收率可达96%。研究了其界面、抗菌、抑菌性质。     

γ-缩水甘油醚氧丙基三甲氧基硅烷的合成

对γ-缩水甘油醚氧丙基三甲氧基硅烷的合成工艺进行了研究。以无水甲醇作溶剂,在组合催化剂存在下,烯丙基缩水甘油醚和三甲氧基硅烷发生硅氢加成反应制得γ-缩水甘油醚氧丙基三甲氧基硅烷。讨论了影响反应的主要因素,得出了最佳合成工艺条件:组合催化剂用量为200μL/mol三甲氧基硅烷、n(烯丙基缩水甘油醚):n(三甲氧基氢硅)=1.2:1、反应温度80℃、反应时间3h。在此条件下,γ-缩水甘油醚氧丙基三甲氧基硅烷的收率可达92.6%。     

1,3-二(3-缩水甘油醚氧基丙基)-1,1,3,3-四甲基二硅氧烷的合成

以四甲基二硅氧烷(HMM)和烯丙基缩水甘油醚(AGE)为原料,在铂催化剂条件下合成1,3-二(3-缩水甘油醚氧基丙基)-1,1,3,3-四甲基二硅氧烷(端环氧基封头剂)。研究了反应温度、反应时间、催化剂用量、HMM和AGE量之比及加料方式对转化率的影响,结果表明,最佳合成条件为n(HMM)∶n(AGE)=1∶2.2,反应温度80℃,反应时间3 h,催化剂用量为20 mg/kg(相对反应物总质量,以铂计),制备的端环氧封头剂转化率可达92.2%。     

2-羟基-3-丁氧基丙基淀粉的制备及性能研究

摘 要：以玉米淀粉为原料,丁基缩水甘油醚为疏水化试剂,氢氧化钠作为催化剂,水作为溶剂,在较温和反应条件下合成了2-羟基-3-丁氧基丙基淀粉(HBPS)。通过考察反应温度、反应时间、碱用量、水用量等因素对取代度和反应效率的影响,确定的最佳的制备条件为：当n(BGE):n(AGU)=0.615时,水用量m(H2O):m(AGU)=2:1、碱用量n(NaOH):n(AGU)=0.5:1、反应温度75℃和反应时间为5h,产品取代度MS=0.45,反应效率为RE=73%。使用IR、1H-NMR、13C-NMR对产物结构进行了表征,证明结构的正确。热重实验表明,疏水基团的引入可提高淀粉的耐热性能。     

2-羟基-3-丁氧基丙基淀粉的制备

以玉米淀粉为原料,丁基缩水甘油醚(BGE)为疏水化试剂,氢氧化钠作催化剂,水为溶剂,在较温和反应条件下合成了2-羟基-3-丁氧基丙基淀粉(HBPS)。考察了反应温度、反应时间、碱用量、水用量和BGE用量等因素对取代度和反应效率的影响,确定了最佳制备条件为:当n(BGE)/n〔淀粉葡萄糖单元(AGU)〕=0.615,m(H2O)∶m(AGU)=2∶1,n(NaOH)∶n(AGU)=0.5∶1,反应温度75℃和反应时间为5h,产品取代度MS=0.45,反应效率RE=73%。用IR、1HNMR、13CNMR对产物结构进行了表征。热重实验表明,疏水基团的引入可提高淀粉的耐热性能。     

2-甲基-α-氧基苯乙酸甲酯的合成研究

2-甲基苯甲酰腈水解制2-甲基-α-氧基苯乙酸甲酯中,物质量比n(2-甲基苯甲酰腈):n(NaCl):n(浓H_2SO_4):n(H_2O)=10∶1∶10∶10,反应温度维持在45℃,反应1.0h,再加入甲醇回流1.5h,可得纯度为90.69%的产物2-甲基-α-氧基苯乙酸甲酯,收率为77.99%.     

1,2-环己二醇二缩水甘油醚的合成及应用

1,2-环己二醇二缩水甘油醚是一种重要的化工产品,通过实验研究,优化了1,2-环己二醇二缩水甘油醚的合成条件,得到了新的最佳合成工艺方案:n(1,2-环己二醇)/n(环氧氯丙烷)=1/2.4;醚化反应温度为60~65℃;环氧化反应温度为35~40℃;最后介绍了1,2-环己二醇二缩水甘油醚的应用。     

4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺的合成研究

以对氯苄醇、3-溴丙炔为起始原料,经过醚化反应合成中间产物1-氯-4-((丙-2-炔-1-基氧基)甲基)苯,再与多聚甲醛、三乙胺经曼尼希反应,合成具有抗心律不齐功能的化合物4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺。通过GC-MS和1H NMR表征了产物结构。确定合成4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺的较优条件为:1-氯-4-((丙-2-炔-1-基氧基)甲基)苯1 mmol,n(1-氯-4-((丙-2-炔-1-基氧基)甲基)苯)∶n(多聚甲醛)∶n(三乙胺)=1∶1∶2,溶剂为二氧六环,催化剂为氯化亚铜,其用量占原料质量的20%,反应温度90℃,反应时间6 h,在上述适宜条件下4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺的得率为74.6%。     

4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺的合成研究

以对氯苄醇、3-溴丙炔为起始原料,经过醚化反应合成中间产物1-氯-4-((丙-2-炔-1-基氧基)甲基)苯,再与多聚甲醛、三乙胺经曼尼希反应,合成具有抗心律不齐功能的化合物4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺。通过GC-MS和1H NMR表征了产物结构。确定合成4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺的较优条件为:1-氯-4-((丙-2-炔-1-基氧基)甲基)苯1 mmol,n(1-氯-4-((丙-2-炔-1-基氧基)甲基)苯)∶n(多聚甲醛)∶n(三乙胺)=1∶1∶2,溶剂为二氧六环,催化剂为氯化亚铜,其用量占原料质量的20%,反应温度90℃,反应时间6 h,在上述适宜条件下4-((4-氯苄基)氧基)-N,N-二乙基丁-2-炔-1-胺的得率为74.6%。     

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.     

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.