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31.
Cai-Yuan Pan Ye Liu Wei Liu 《Journal of polymer science. Part A, Polymer chemistry》1998,36(16):2899-2903
Cationic polymerization of 1,3-dioxepane (DOP) initiated by triflic acid was carried out in the presence of 2,2-bis(hydroxymethyl)butanol (BHMB). The structure and molecular weight of the products were characterized by GPC and NMR spectra. The results showed that molecular weight of the polyacetal obtained could be controlled by the initial mole ratio of DOP/BHMB. GPC showed that as the mole ratio of BHMB/DOP increased, the content of cyclic oligomers also increased. Proton, 13C and 2D HMQC-fg NMR demonstrated that no hydroxymethyl group of BHMB appeared as an end group. It was also illustrated by proton NMR that some BHMB units existed in cyclic oligomers. The mechanism of formation of cyclic oligomers was discussed. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2899–2903, 1998 相似文献
32.
Tabito Ikezaki Reishi Matsuoka Kenichi Hatanaka Naoko Yoshie 《Journal of polymer science. Part A, Polymer chemistry》2014,52(2):216-222
We synthesized biobased poly(2,5‐furandimethylene succinate‐co‐butylene succinate) [P(FS‐co‐BS)] copolymers by polycondensation of 2,5‐bis(hydroxymethyl)furan, 1,4‐butanediol, and succinic acid. These copolymers could be crosslinked to form network polymers by means of a reversible Diels–Alder reaction with bis‐maleimide. The thermal properties, mechanical properties, and healing abilities of the P(FS‐co‐BS)s and the network polymers were investigated. The mechanical properties of the network polymers depended on the comonomer composition of the P(FS‐co‐BS)s and the maleimide/furan ratio in the network polymers. Some of the copolymers exhibited healing ability at room temperature, and their healing efficiency was enhanced by solvent or heat. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 216–222 相似文献
33.
The title compound 3,9-bis(pyridin-2-yl)-2,4,8,10-tetraoxaspiro[5.5]undecane 4(C17H18N2O4) has been synthesized by the reaction of 2,2-bis(hydroxymethyl)propane-1,3-diol with pyridine-2-carbaldehyde in the presence of p-toluenesulfonic acid,and characterized by IR,1H-NMR and X-ray single-crystal diffraction.The crystal belongs to monoclinic system,space group C2/c with a = 25.133(2),b = 5.7219(5),c = 21.942(2) ,β = 99.145(2)°,V = 3115.3(5)3,Z = 8,Dc = 1.340 g/cm3,Mr = 314.33,F(000) = 1328,μ = 0.097 mm-1,MoKa radiation(λ = 0.71073),R = 0.0352 and wR = 0.1022 for 2486 observed reflections with I > 2σ(I).X-ray analysis reveals that the two 1,3-dioxane rings passing through the central spiro-C atom both adopt chair conformation.Intermolecular C-H…π,C-H…O and C-H…N weak interactions link the molecules to form a three-dimensional samdwich,which are effective in the stabilization of the crystal structure. 相似文献
34.
María del Mar Castro López M.C. Cela PérezMaría Sonia Dopico García José Manuel López VilariñoMaría Victoria González Rodríguez Luis F. Barral Losada 《Analytica chimica acta》2012
Molecularly imprinted polymer (MIP) for solid extraction and preconcentration of catechins have been successfully prepared by a thermal polymerization method using quercetin as template, 4-vinylpyridine as functional monomer and ethylene glycol dimethacrylate as crosslinker. A solution mixture of acetone and acetonitrile was used as porogen. Systematic investigations of the influence of monomer, cross-linker, porogen, as well as polymerization conditions on the properties of the MIPs were carried out. The quercetin MIPs were evaluated according to their selective recognition properties for quercetin, structurally related compounds (catechin, epigallocatechin gallate and epicatechin) and a unrelated compound of similar molecular size (α-tocopherol). Good binding was observed for quercetin, catechin and epigallocatechin gallate with an optimized MIP in a solid phase extraction system. Adsorption and kinetic characteristics were evaluated for catechins which indicated that the synthesized polymer had high adsorption capacity and contained homogeneous binding sites. Chemical and morphological characterization of the MIP was investigated by FTIR, SEM and BET, which confirmed a high degree of polymerization. Finally, the MIP was successfully applied to the clean-up and preconcentration of catechins from several natural samples. 相似文献
35.
超支化聚醚的支化度对玻璃化转变温度的影响 总被引:2,自引:0,他引:2
聚合物的分子结构对聚合物性能影响很大.支化度不同的同种聚合物,必须通过不同的催化体系合成,很难得到既具有相近分子量又具有不同支化度的系列聚合物样品,因此对聚合物性能与支化度的依赖关系的研究报道不多. 相似文献
36.
The influence of [(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)amino]-1-propanesulfonic acid (TAPS) on solutions containing lead(II) was studied by direct current polarography (DCP) and glass electrode potentiometry (GEP). The readings were taken at fixed total TAPS to total lead(II) concentration ratios and various pH values, at 25.0 ± 0.1 °C and ionic strength 0.1 M KNO3.Due to the basic pKa of the ligand, which occurs in the pH range where large amount of lead polynuclear species are formed, and the occurrence of ligand adsorption, that disabled the use of high concentrations of TAPS on DCP experiments, GEP and DCP experimental conditions were put to the limit in order to provide the correct Pb-TAPS-OH model and reliable stability constants.The proposed final model is: PbL, PbL2, PbL2(OH) and PbL2(OH)2 with overall stability constants values, as log β, 3.27 ± 0.06, 6.5 ± 0.1, 12.7 ± 0.1 and 17.27 ± 0.06, respectively.A comparative analysis of the strength of complexation of TAPS and a structural related buffer, 2-hydroxy-3-[tris(hydroxymethyl)methylamino]-1-propanesulfonic acid (TAPSO), with lead is also discussed. 相似文献
37.
A. M. Korolev L. T. Eremenko L. V. Meshikhina I. L. Eremenko S. E. Nefedov 《Russian Chemical Bulletin》1998,47(3):462-464
The first representative of organic nitrates of the oxazoline series, 4,4-dihydroxymethyl-2-(3-pyridyl)-2-oxazoline dinitrate,
was synthesized by the reaction ofN-nicotinoyltri(hydroxymethyl)aminomethane trinitrate hydronitrate (1) with a solution of KOH in alcohol. The reactivities of compound1 andN-nicotinoylethanolamine nitrate (nicorandil) in the reaction of intramolecular heterocyclization were compared. The structure
of the compound synthesized has been established by X-ray diffraction analysis.
For Part 1, see Ref. 1
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 478–481, March, 1998. 相似文献
38.
V. V. Zakharov G. P. Bugaeva M. E. Ivanova L. B. Romanova L. T. Eremenko S. E. Nefedov I. L. Eremenko 《Russian Chemical Bulletin》1998,47(7):1349-1352
An efficient procedure for the preparation of 1,4-bis(hydroxymethyl)cubane by reduction of cubane-1,4-dicarboxylic acid or
its dimethyl ester with aluminum hydride was developed. The molecular structure of 1,4-bis(hydroxymethyl)cubane was established
by X-ray diffraction analysis.
For Part 3, see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1387–1390, July, 1998. 相似文献
39.
2,2-二羟甲基-1,3-丙二醇单缩醛的合成 总被引:2,自引:0,他引:2
引言2,2-二羟甲基-1,3-丙二醇(以下称季戊四醇)单缩醛是有机合成的重要中间体。我们曾用季戊四醇单缩醛与氢化钠及1,3-丙磺内酯反应合成了一系列含有1,3-二氧六环的磺酸盐型可断裂表面活性剂[1]。目前,有关季戊四醇单缩醛的文献报道极少。Conr... 相似文献
40.
Enthalpies of proton transfer in methanol-water mixtures (0–90 wt. % methanol) have been measured by direct calorimetry for the bases 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-propanediol and 2,2-bis(hydroxymethyl)-2,2,2-nitrilotriethanol at 25°C. Also reported are the data for 3-hydroxy-2-methyl-4-pyrone. The results are discussed in terms of an adaptation of classical electrostatic formula. 相似文献