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1.
液相合成γ—丁内酯新型催化剂 总被引:2,自引:0,他引:2
液相合成γ┐丁内酯新型催化剂林衍华*骆有寿(浙江大学二次资源化工国家专业实验室杭州310027)关键词γ-丁内酯,1,4-丁二醇,Cu-Zn-O催化剂,绿铜锌矿1996-12-04收稿,1997-06-06修回γ-丁内酯是一种精细化学品,用作高沸点、... 相似文献
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多功能光学活性丁二醇衍生物的合成和结构 总被引:5,自引:0,他引:5
通过新的合成策略,以手性合成子3和具有生物活性的有机碱类化合物4为反应底物,利用Michael不对称加成反应,合成得到光学纯的5-(R)-[(1R,2S,5R)-(-)-氧基]-4-(R)-(杂环碱基)-2(5H)-呋喃酮(5). 加成物5通过还原反应得到了多功能光学活性的二醇类化合物6,产率为42%~82%,e.e.≥98%. 化合物6的化学结构得到了确认,其立体化学结构和绝对构型经X射线晶体学测定得到了确定. 相似文献
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Darwin P. R. Kint Emilia Wigstrm Antxon Martínez de Ilarduya Abdelilah Alla Sebastin Muoz‐Guerra 《Journal of polymer science. Part A, Polymer chemistry》2001,39(19):3250-3262
Novel poly(ethylene terephthalate) (PET) copolyesters, abbreviated PEDMBT, containing optically active (2S,3S)‐2,3‐dimethoxy‐1,4‐butanediol (DMBD) as the second comonomer were investigated. Copolymers with ethylene glycol to DMBD ratios between 95/5 and 50/50 as well as the two parent homopolymers, PET and PDMBT, were prepared by a two‐step melt polycondensation. The resulting copolymers were found to approximately have the composition of the polymerization reaction feed and a random microstructure. Polymer intrinsic viscosities varied from 0.4 to 0.6 dL g?1 with weight‐average molecular weights ranging from 16,000 to 44,000. PEDMBT copolyesters were distinguished in being much more soluble than PET and showing an increasing affinity for water with the content in dimethoxy groups. According to the asymmetric constitution of DMBD, they displayed optical activity in solution. Both melting and glass‐transition temperatures of the copolyesters were observed to steadily decrease with the content in DMBD. PEDMBTs were found to be crystalline for contents in DMBD up to 30 mol %. Both powder and fiber X‐ray diffraction revealed that the same crystalline structure is shared by PET and the crystalline copolyesters. The homopolyester PDMBT resulted in becoming a polymer with a crystallinity comparable to PET but with a significantly different crystalline structure. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3250–3262, 2001 相似文献
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G. F. Pavelko 《Russian Chemical Bulletin》2006,55(8):1436-1439
The influence of O2 and H2O on the formation of iron dithiolates (IDTs) by the reactions of thiols and organic disulfides with the iron powder was studied
under the static (without mechanical activation of the reaction) and dynamic (with mechanical activation of the reaction)
conditions. Under the static conditions in the absence of O2 or H2O, only BnSH and PhSH give IDTs, whereas DdSH (Dd is dodecyl) produces IDTs in the presence of O2 or H2O. For the mechanical activation of the reactions of organic disulfides with the iron powder, the formation of IDTs is possible
if the reaction mixture contains H2O. On the interaction with iron oxides excess thiols are oxidized to organic disulfides and also afford IDTs.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1383–1386, August, 2006. 相似文献
7.
Albert J. B. Loman Leen van der Does Adriaan Bantjes Ivan Vulic 《Journal of polymer science. Part A, Polymer chemistry》1995,33(3):493-504
Results are reported on the effect of lateral methyl groups on the thermal properties of a series of polyesters prepared from diethyl 4,4′-biphenyldicarboxylate and various methyl substituted 1,4-butanediols. The diols were 1,4-butanediol; 2-methyl-1,4-butanediol; 2,2-dimethyl-1,4-butanediol; 2,3-dimethyl-1,4-butanediol; 2,2,3-trimethyl-1,4-butanediol; and 2,2,3,3-tetramethyl-1,4-butanediol. Apart from the tetramethyl derivatve, the transition temperatures of the methyl substituted polyesters were lower with respect of the unsubstituted polyester. On the basis of polarized photomicrographs, a smectic A mesophase was found for the unsubstituted polyester, whereas a nematic mesophase was observed for the 2-methyl substituted polyster. The 2,2-dimethyl, 2,3-dimethyl, and the 2,2,3-trimethyl substituted polyesters showed no liquid crystalline behavior. The 2,2,3,3-tetramethyl derivative displayed a birefringent melt phase although the DSC measurements were not unambiguous. A copolyester based on diethyl 4,4′-biphenyldicarboxylate, 1,4-butanediol, and 2,2,3,3-tetramethyl-1,4-butanediol showed a broad nematic mesophase. Further evidence for the nematic mesophase of this copolyester and the 2-methyl substituted polyester was provided by dynamic rheological experiments. Based on thermogravimetric analysis, it was concluded that the thermal stability was affected only when four methyl side groups were present in the spacer. © 1995 John Wiley & Sons, Inc. 相似文献
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S.K. Mehta Ganga Ram Rajat Chauhan K.K. Bhasin 《The Journal of chemical thermodynamics》2009,(12):1329-1338
The thermodynamic parameters viz. excess molar volume VE and speed of sound u, transport parameter viscosity η, and spectroscopic parameters viz. IR, 1H, 13C NMR have been measured for the mixtures of isomeric butanediol (1,2-, 1,3-, 1,4-, and 2,3-butanediol) and N-methyl-2-pyrrolidinone over the whole composition range at 308.15 K. The partial molar quantities , isentropic compressibility , viscosity deviation Δη, deviation in Gibbs free energies of activation for viscous flow g(x), and excess NMR chemical shift δE have been estimated and analyzed. Results show that the interaction between unlike molecules takes place through hydroxyl groups of isomeric butanediol and CO group of N-methyl-2-pyrrolidinone. Excellent agreement between thermodynamic and spectroscopic measurements is observed. 相似文献
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The enthalpies, entropies and Gibbs energies of inclusion of dl-1,3-, 1,4- and meso-2,3-butanediols into α- and β-cyclodextrin cavities from ideal gas phase have been determined on the basis of newly obtained
experimental data of the butanediols. The butanediol molecules are stabilised strongly in the cavities due to interactions
with inner walls of the cavities. Entropies of the gaseous isomers are greatly decreased in the cavities. The largest decrease
is obtained for the case of 2,3-BD. Discussions concerning the1,4-butanediol given in the preceding paper have been changed
due to the adoption of new data on the butanediols.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Gui Zhi Li Hosouk Cho Lichang Wang Hossein Toghiani Charles U. Pittman 《Journal of polymer science. Part A, Polymer chemistry》2005,43(2):355-372
Poly[isobutyl methacrylate‐co‐butanediol dimethacrylate‐co‐3‐methacrylylpropylheptaisobutyl‐T8‐polyhedral oligomeric silsesquioxane] [P(iBMA‐co‐BDMA‐co‐MA‐POSS)] nanocomposites with different crosslink densities and different polyhedral oligomeric silsesquioxane (MA‐POSS) percentages (5, 10, 15, 20, and 30 wt %) were synthesized by radical‐initiated terpolymerization. Linear [P(iBMA‐co‐MA‐POSS)] copolymers were also prepared. The viscoelastic properties and morphologies were studied by dynamic mechanical thermal analysis, confocal microscopy, and transmission electron microscopy (TEM). The viscoelastic properties depended on the crosslink density. The dependence of viscoelastic properties on MA‐POSS content at a low BDMA loading (1 wt %) was similar to that of linear P(iBMA‐co‐MA‐POSS) copolymers. P(iBMA‐co‐1 wt % BDMA‐co‐10 wt % MA‐POSS) exhibited the highest dynamic storage modulus (E′) values in the rubbery region of this series. The 30 wt % MA‐POSS nanocomposites with 1 wt % BDMA exhibited the lowest E′. However, the E′ values in the rubbery region for P(iBMA‐co‐3 wt % BDMA‐co‐MA‐POSS) nanocomposites with 15 and 30 wt % MA‐POSS were higher than those of the parent P(iBMA‐co‐3 wt % BDMA) resin. MA‐POSS raised the E′ values of all P(iBMA‐co‐ 5 wt % BDMA‐co‐MA‐POSS) nanocomposites in the rubbery region above those of P(iBMA‐co‐5 wt % BDMA), but MA‐POSS loadings < 15 wt % had little influence on glass‐transition temperatures (Tg's) and slightly reduced Tg values with 20 or 30 wt % POSS. Heating history had little influence on viscoelastic properties. No POSS aggregates were observed for the P(iBMA‐co‐1 wt % BDMA‐co‐MA‐POSS) nanocomposites by TEM. POSS‐rich particles with diameters of several micrometers were present in the nanocomposites with 3 or 5 wt % BDMA. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 355–372, 2005 相似文献