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1.
H. Balard M. Sidqi E. Papirer J. B. Donnet A. Tuel H. Hommel A. P. Legrand 《Chromatographia》1988,25(8):712-716
Summary The surface properties of silicas modified with – diols having between 4 and 16 carbon atoms were investigated by inverse gas chromatography. It is shown, that the value of the dispersive component of the surface energy does not change monotonously: a minimum value is recorded when the surface is covered by a monolayer of methylene groups. Further, when measuring the adsorption enthalpies of polar probes, an alternation of their H values is observed: grafts having an odd number of carbon atoms systematically show higher H values than the others. A trans-trans configuration of the grafted chains which allows optimum interactions is proposed, suggesting a preferential diesterification reaction of both terminal hydroxyl groups of odd diols. 相似文献
2.
Gianna Borghesani Rodolfo Pedriali Fernando Pulidori 《Journal of solution chemistry》1989,18(3):289-300
The heats of dilution and the osmotic coefficients for some aliphatic diols (1,3-propanediol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol; 2,3-butanediol; 1,5-pentanediol; 1,6-hexanediol) in water at 25°C are reported. The experimental free energy and enthalpy pairwise interaction coefficients were evaluated and are discussed in terms of the hydrophobic-hydrophilic properties of the solutes. The effect of the mutual position of the polar hydrophilic groups in the molecule on the experimental interaction coefficients transposed to the McMillan-Mayer (MM) state is emphasized. The Sawage-Wood additivity of groups (SWAG) approach has been used and critically discussed.Paper presented at J.C.A.T. '86-Ferrara 27–30 Ottobre 1986. 相似文献
3.
Hans R. Kricheldorf Majdi Al Masri 《Journal of polymer science. Part A, Polymer chemistry》1995,33(15):2667-2671
Attempts were made to synthesize poly(ether-sulfone)s from aliphatic diols or bissilylated diols on the one hand, and 4,4′-dichlorodiphenylsulfone or 4,4′-difluorodiphenylsulfone on the other hand. The reaction conditions and the catalyst were varied. Polycondensations of silylated diols with 4,4′-difluorodiphenylsulfone and powdered K2 CO3 in N-methylpyr-rolidone proved to give the best results. Using silylated isosorbide and isomannide as mono-mers chiral poly(ether-sulfone)s were prepared. GPC measurements indicate weight-average molecular weights in the range of 27×103–200×103. © 1995 John Wiley & Sons, Inc. 相似文献
4.
Recent results obtained on determining the extraction efficiency and composition of organic volatiles in Oregano Water obtained from Origanum onites L. are described. Oregano Water was subjected to liquid-liquid extraction with a range of solvents with different polarities and each extract was analyzed by GC/MS. 相似文献
5.
Harald Høiland 《Journal of solution chemistry》1977,6(5):291-297
The isentropic coefficients of compressibility of the homologous series of alcohols and diols R
n
CH2OH (n=2–6), CH3CHOHR
n
(n=1–5), 1,2-propanediol, 1,3- 1,4- and 2,3-butanediol, 1,5-pentanediol, and 1,7-heptanediol dissolved in propylene carbonate have been measured at 25°C. Isentropic partial molal compressibilities and group partial molal compressibilities at infinite dilution have been evaluated. The isentropic partial molal compressibilities of these alcohols and diols have been compared with the corresponding values in water. This comparison shows that the values in propylene carbonate are higher than in water by a factor of 10 due to an increased compressibility of the solvation sheath around nonpolar groups in PC. 相似文献
6.
H. Balard M. Sidqi E. Papirer J. B. Donnet A. Tuel H. Hommel A. P. Legrand 《Chromatographia》1988,25(8):707-711
Summary Silica has been modified by an esterification reaction using either n-alcohols or - diols. The grafting ratios were evaluated by elemental analysis of carbon or by the weight loss of the grafted silica heated to 700°C. The grafting ratio can be easily fixed by changing the silica to reactant impregnation ratios. In the case of n-alcohols, the grafting ratios do not vary monotonously with the number of carbon atoms of the grafts and the density of the grafted layer is 25% higher for - diols than for n-alcohols. This observation needs further investigation. 相似文献
7.
8.
A facile method to synthesize high‐molecular‐weight biobased polyesters from 2,5‐furandicarboxylic acid and long‐chain diols 下载免费PDF全文
Vasilios Tsanaktsis George Z. Papageorgiou Dimitrios N. Bikiaris 《Journal of polymer science. Part A, Polymer chemistry》2015,53(22):2617-2632
In this study, biobased furan dicarboxylate polyesters have been prepared using 2,5‐furandicarboxylic acid (FDCA) and diols with high number of methylene groups (long‐chain diols), namely, 8, 9, 10, and 12. Because of the high boiling points of these diols, a modified procedure of the well‐known melt polycondensation was applied in this work. According to this, the dimethyl ester of FDCA (DMFD) reacted in the first transesterification stage with the corresponding diols forming bis‐hydroxy‐alkylene furan dicarboxylates (BHFD). In the second stage, the BHFD reacted with DMFD again at temperatures of 150–170 °C (for 4–5 h), and in the final stage, the temperature was raised to 210–230 °C (vacuum was applied for 2–3 h). The molecular weight of the polyesters and the content of oligomers, as was verified by gel permeation chromatography analysis, depend on the polycondensation time and temperature. The chemical structure of the polyesters was verified from 1H NMR spectroscopy. All the polymers were found to be semicrystalline, with melting temperatures from 69 to 140 °C depending on the diol used. In addition, the mechanical properties also varied with the type of diol. The higher values were observed for poly(octylene 2,5‐furanoate), whereas the lowest values were observed for poly(dodecylene 2,5‐furanoate) with the higher number of methylene groups in its repeating unit. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2617–2632 相似文献
9.
D. D. Enchev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2127-2130
The synthesis of the titled compounds have been discussed. 相似文献
10.
《Angewandte Chemie (International ed. in English)》2017,56(43):13377-13381
A catalytic pinacol‐type reductive rearrangement reaction of internal 1,2‐diols is reported herein. Several scaffolds not usually amenable to pinacol‐type reactions, such as aliphatic secondary–secondary diols, undergo the transformation well without the need for prefunctionalization. The reaction uses a simple boron catalyst and two silanes and proceeds through a concerted, stereoinvertive mechanism that enables the preparation of highly enantiomerically enriched products. Computational studies have been used to rationalize the preference for migration over direct deoxygenation. 相似文献