丙烯酸正丁酯聚合的Diels-Alder反应机理理论研究

本文从理论上对丙烯酸正丁酯(nBA)自引发聚合的Diels-Alder反应机理进行了研究.利用DFT方法在UB3LYP/6-31G*水平上对反应的最低能量路径进行了计算,各驻点能量分别采用MP2/6-311G**和B3LYP/6-311 G(3df;2p)进一步精确计算.结构表明:此Diels-Alder反应仅包括一种途径,即路径(I),另一条途径在热力学不支持.     

含稠环基团的有机硅化合物及聚合物的研究 IV.含取代苊基有机硅烷的合成

利用乙烯基三乙氧基硅烷和烯丙基三乙氧基硅烷与苊式环戊二烯酮通过Ｄｉｅｌｓ－Ａｌｄｅｒ反应合成两种新的含取代苊基的有机硅化合物，并对新化合物进行了相应的组成和结构分析。     

替卡格雷关键中间体手性氨基环戊三醇的合成

以D-丙氨酸为原料,经酯化、Boc保护氨基、酯基羟胺化、羟胺氧化、Diels-Alder加成、烯烃双羟基化、邻二羟基的亚异丙基保护、脱N-酰基保护基、钯炭催化氢解等反应制备了(1S,2R,3S,4R)-2,3-O-亚异丙基-4-氨基环戊烷-1,2,3-三醇(Ⅰ)。对工艺路线中影响收率的关键步骤进行了反应条件优化。结果表明:(R)-N-Boc-丙氨酸异羟肟(Ⅴ)的制备采用(R)-N-Boc-丙氨酸甲酯(Ⅳ)为原料,收率为90.0%;(R)-2-(叔丁氧羰基)氨基-1-[(1S,4R)-2-氧杂-3-氮杂双环[2.2.1]庚-5-烯-3-基]丙-1-酮(Ⅵ)的制备采用Swern氧化和Diels-Alder环加成"一锅"反应,收率为83.1%;(2R)-2-(叔丁氧羰基)氨基-1-[(1S,4R,5R)-5,6-二羟基-2-氧杂-3-氮杂双环[2.2.1]庚-3-基]丙-1-酮(Ⅶ)的制备过程中使用了廉价且低毒的高锰酸钾,收率达85.0%。改进后目标产物的总收率达到了59.8%。     

Spaced-amine modified SBA-15: Synthesis and characterization

A novel kind of spaced-amine modified mesoporous silica (SBA-15-NH₂) was synthesized via the Diels-Alder reaction of fumaronitrile and cyclopentadienyl-modified SBA-15 (SBA-15-Cp), followed by the reduction of cyano groups using NaBH₄/I₂ as reductant and Diglyme as solvent. The synthesized materials were characterized by X-ray diffraction (XRD), N₂-sorption, transmission electron microscopy (TEM), Fourier Transform Infrared (FTIR) and thermogravimetric analysis (TGA). The mesostructure was kept well after reaction with fumaronibrile and the reduction of cyano groups. SBA-15-NH₂ has an amine loading of 0.95 mmol NH₂/g and shows high activity, selectivity and reusability in the Knöevenagel condensation of benzaldehyde and malononitrile.     

Copolymers of acrylonitrile with some furans and their Diels-Alder adducts

Copolymers of acrylonitrile with furan, 2-methylfuran and with 2,5-dimethyl furan have been prepared by free radical copolymerizations, and their ¹³C spectra examined for evidence of the three types of structure that formed, according to previous studies. We have characterized the Diels-Alder adducts of acrylonitrile with furan and with 2-methylfuran, and have found that they may also copolymerize with acrylonitrile by addition at their double bonds. The enchained adducts were most readily recognized in the ¹H spectrum by shifts at 4.8 and 4.6 ppm respectively from protons at the oxygen bridgehead. The ¹³C spectra of these various polymers have been assigned with the aid of model compounds. Below δ=60 ppm the nitrile shift was dispersed over a larger range of shifts than is found in PAN itself, and was joined by the shifts of unsaturated carbon atoms and of carbon atoms linked to the oxygen atoms within these structures. Above 60 ppm the shifts of carbons in acrylonitrile units were found to be perturbed systematically from their normal places by the presence of neighbouring structures formed from the different furan-containing molecules. In both the ¹H and ¹³C spectra shifts characteristic of the end groups from the AIBN initiator were noted. Fine structure in the spectra was attributed to monomer sequence effects and to the tactic structure of the polymer. Chiral centres appeared to be created from the furan rings at random, at least when protonated carbons were the site of initial attachment, but the mode of addition to the ring—whether cis, trans or both, was not certain. Assignments were made of bands in the i.r. spectra to modes of vibration of the units formed from the furan monomers.     

氯菌酸酐的合成

报道了1种改进的氯菌酸酐合成法。该法用甲苯作溶剂,由六氯环戊二烯与顺酐进行Diels-Alder反应制取氯菌酸酐,产率可达70％～80％。     

负载型AlCl_3催化共轭二烯烃与顺丁烯二酸酐的反应

催化裂化轻汽油烷基化、异构化与醚化是降低汽油烯烃含量、提高辛烷值的重要加工过程 ,为保证这些过程的催化剂寿命 ,必须脱除催化裂化轻汽油中的共轭二烯烃。制备了AlCl3 /Al2 O3 催化剂 ,用于催化顺丁烯二酸酐与催化裂化轻汽油中共轭二烯烃的Diels-Alder反应。考察了反应条件对共轭二烯烃转化率的影响 ,在反应温度 80℃ ,n(酸酐 ) /n(二烯 ) =1.1,反应时间 4h ,反应压力 1.0MPa的条件下 ,共轭二烯烃的转化率可达 90 %以上 ,并且催化剂稳定性好。处理过的催化裂化轻汽油作为醚化反应的原料 ,醚化催化剂使用寿命大大延长     

端羟基马来松香酯的制备及应用

对松香与顺丁烯二酸酐的Ｄｉｅｌｓ－Ａｌｄｅｒ反应进行了研究，讨论了反应温度、反应时间和反应物摩尔比对反应的影响；并进一步制得端羟基马来松香；对含端羟基马来松香酯的硬质聚氨酯泡沫塑料的耐热性进行了研究。     

基于热可逆Diels-Alder动态共价键PU-DA体系的制备和性能

使高度柔性的聚四氢呋喃二醇(PTMG)基材与糠基缩水甘油醚-2-呋喃甲胺(FGE-FA)反应得到四元呋喃结构的聚氨酯预聚物,再将其与含亲双烯体结构的双马来酰亚胺反应制备出高密度Diels-Alder(DA)动态共价键结构的自修复聚氨酯(PU-DA)。用FTIR、DSC和OM表征PU-DA的结构,用电子万能试验机测试了PU-DA的性能。结果表明：在PU-DA中引入了DA动态共价键后, 其正、逆反应温度分别为70℃和132℃;PU-DA具有良好的重塑性、溶胀溶解性和多次自修复性能。受损试样在70℃修复4 h裂纹即基本愈合,第一次修复率可达94.8%,三次修复率仍高于70%。