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Dodecylbenzenesulfonic acid (DBSA) was proved to be an efficient catalyst for Prins cyclization of styrenes and formaldehyde or acetaldehyde in water. A tandem dehydration/Prins cyclization reaction using a tertiary alcohol and formaldehyde as substrates proceeded very well by using DBSA as catalyst. Acetophenone, which is less reactive compared with styrene, can also react with formaldehyde when catalyzed by DBSA in water to afford 1,3-dioxan-5-ylphenylmethanone in good yield. 相似文献
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十二烷基苯磺酸/异辛烷微乳液中脂肪酶催化合成异丁酸异戊酯 总被引:5,自引:0,他引:5
在十二烷基苯磺酸(DBSA)/异辛烷微乳液中进行了脂肪酶催化合成异丁酸异戊酯的反应, 考察了微乳体系的含水量w0、溶解酶缓冲溶液的pH值、反应温度等因素对酯合成反应转化率的影响; 与前期研究的CTAB微乳体系进行比较发现, DBSA微乳体系中的酯合成反应速率明显增加, 短时间内的转化率显著提高, 在温和条件下反应9 h后, 转化率达90%以上; 通过DBSA体系中有酶与无酶条件下反应进程的比较得知, DBSA作为一种质子酸对酯合成反应具有一定的催化能力; 提出了该体系中微乳催化、酶催化和质子酸催化的三重催化机理. 相似文献
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The esterification of octanoic acid with octanol in microemulsion and emulsion system is studied. In the presence of 5–10% dodecylbenzene-sulfonic acid (DBSA), which is a surfactant-type catalyst, high conversion of esterification can be given both in microemulsion and in emulsion system. Compared with emulsion system, single-phase microemulsion is a more effective reaction system for esterification, with the advantages of comparatively little influence by the amount of water, no need of hard stirring, and stable state when laid long. The esterification of other fatty acids and alcohols in this reaction system were also accomplished in favorable conversion. 相似文献
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MohammadSaleemKhan ZarshadAli 《高分子科学》2005,(1):29-35
Dodecyl benzenesulfonic acid (DBSA) surfactant was used in the present study to find the effect of concentration on its electrical conductance in solution from 293-323K above and below the critical micelle concentration (CMC). The micellization parameters i.e. degree of counter ion binding (β), aggregation number (n) and number of counter ion micelle(m) were measured. The interaction of DBSA with polyvinylpyrrolidone (PVP) was also studied at 293K throughconductance and surface tension measure ments. A number of important parameters i.e. critical aggregation concentration (CAC), Gibb‘s free energy (△G) and binding ratio (R) were determined and the effect of NaCl on the CAC and polymer saturation point (PSP) was also investigated. 相似文献
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We report herein the use of p-dodecylbenzenesulfonic acid(DBSA) as a catalyst for a one-pot Biginelli reaction to afford 3,4- dihydropyrimidinone derivatives in good to excellent yields.This reaction proceeds efficiently in water and under solvent free conditions.Comparisons of results indicate that although the yields are high and comparable for both methods,the reaction times are considerably shorter under solvent free conditions. 相似文献
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Polyaniline soluble in organic solvents was prepared using dodecylbenzenesulphonic acid (DBSA) as functional dopant. The solubility parameter was calculated and the most suitable solvent chloroform was checked for the solubility and the most compatible polymer PMMA was selected for blending. Miscibility was maximized with 1% by weight of hydroquinone. Blending of doped polyaniline with dodecylbenzenesulphonic acid (PAni.DBSA) in poly (methyl methacrylate) (PMMA) was explained by a change in the conformation of the polymeric chains leading to an increase in the conductivity. The electrical conductivity increased as the weight percent of PAni.DBSA increased, showing a percolation threshold as low as 3.0% by weight and the highest conductivity was achieved at 20% by wt of PAni.DBSA. Scanning electron micrographs showed lowest level of phase separation. Raman spectroscopy is used to characterize the blending process of two polymers aiming to understand the transformations in different types of charged segments. Raman results give complementary data about the blending process showing that together with the structural change of the polymeric chains, there is also a chemical transformation of these polymers. Analysis of Raman spectra was done investigating the relative intensities of the bands at 574 cm−1 and 607 cm−1. A relationship between conductivity and Raman was also proposed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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导电聚苯胺与Fe3O4磁性纳米颗粒复合物的合成与表征 总被引:28,自引:0,他引:28
对十二烷基苯磺酸(DBSA)掺杂的导电聚苯胺(PAn-DBSA)的氯仿溶液,在pH为中性的条件下,采用“修饰-再掺杂(Modification-re-doped)法”合成了含有Fe3O4磁性纳米颗粒的导电聚苯胺复合物的有机溶液.用FTIR,XRD,TEM,UV-Vis和SQUID等对所得复合物进行了表征,结果表明,该复合物呈现超顺磁性和半导体的导电性,并具有较好的透明性. 相似文献
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《Current Applied Physics》2015,15(5):599-607
A new composite material from epoxidized natural rubber (ENR-50) and polyaniline have been successfully prepared. Aniline which was polymerized in the presence of dodecylbenzene sulfonic acid (DBSA), then added to ENR-50 for the preparations of ENR-50/Pani.DBSA composite films. The hydrogen bonding which contribute to the formation of ENR-50/Pani.DBSA composites was observed in FT–IR, UV–Visible and DSC. It showed hydrogen bonding interactions between the epoxy groups in ENR-50 and the amine groups in Pani.DBSA. The morphologies of the prepared materials were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and conductivity measurements revealed that the percolation threshold is at 2.5 w% of Pani.DBSA content. Atomic force microscopy (AFM) micrographs showed that ENR-50 with 5 wt% Pani.DBSA addition has the lowest surface roughness. In addition thermogravimetric analysis indicates improved thermal stability at low Pani.DBSA content. DSC measurements revealed that Tg value increases with increasing Pani.DBSA, indicating that the formation of homogenous composite material. Nanoindentation results show that the hardness (H) and Young's modulus (Es) increased with higher addition of Pani.DBSA polymer. 相似文献
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This paper is an extension of previous work on polymerization of anilinium–DBSA (dodecylbenzenesulfonic acid) in an aqueous dispersion in the presence of mica or talc silicate particles. The presence of mica or talc particles greatly accelerates the polymerization process of anilinium‐DBSA and an encapsulated structure is formed as well. The catalytic effect of various metallic cations which exist in the chemical compositions of mica or talc on the polymerization kinetics of anilinium‐DBSA was investigated. The conductivity results along with microscopy observations prove a well formed encapsulated structure for the polyaniline/mica composites, but less for the polyaniline/talc composites. The anilinium‐DBSA complex and mica aqueous dispersions pretreated at different temperatures prior to polymerization have shown a significant effect on the polymerization rate of anilinium‐DBSA. The higher the dispersion temperature, the higher is the polymerization rate found. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献