共查询到20条相似文献,搜索用时 93 毫秒
1.
芳氧乙酸-3,3-二甲基-2-羰基丁酯衍生物的合成与生物活性史延年,李士明,方建新(南开大学元素有机化学研究所,天津,300071)关键词芳氧乙酸酯,合成,生物活性芳氧乙酸及其酯类衍生物具有良好的生物活性.作者曾以苯氧乙酸类化合物为母体,合成了一系列... 相似文献
2.
芳氧(硫)乙酸合成方法的改进 总被引:3,自引:0,他引:3
芳氧(硫)乙酸合成方法的改进包明贺庆林何晓智刘宝殿*(东北师范大学化学系长春130024)关键词芳氧乙酸,芳硫乙酸,合成1996-08-30收稿,1997-03-20修回吉林省科委应用基础研究资助课题芳氧(硫)乙酸可作杀菌剂和植物生长调节剂,其中芳硫... 相似文献
3.
从α-蒎烯直接催化酯化高选择性地合成乙酸正龙脑酯的研究-催化剂与反应机理初探 总被引:1,自引:0,他引:1
本文提出了新的硼酸类催化剂体系HB,用该体系对α-蒎烯与无水乙酸相互作用直接合成乙酸正龙脑酯作了较系统的研究。反应得到两种系列产物-酯化产物和异构化产物,酯化产物主要是乙酸正龙脑酯,葑醇酯和松油酯,异构化产物主要是莰烯、烯和松油烯等,总酯化产率为50%以上,其中乙酸正龙脑酯为20%以上,是至今从α-蒎烯直接合成乙酸正龙脑酯的最好结果。通过对产物的 ̄1HNMK图谱分析及动力学考察,确证反应主产物是正龙脑酯而不是异龙脑酯。文章对H_2SO_4、HClO_4、多聚磷酸(PPA)和杂多酸(12-磷钨酸)等催化剂进行了实验考察、对比和评述,表明了自制的HB催化剂体系具有高选择性合成乙酸正龙脑酯的显著优点,并对其反应机理作了初步探讨。 相似文献
4.
5.
一锅法合成金属配合物是近年来金属有机化学研究的一个热点之一。在对国内外噁唑啉金属配合物的合成及应用进行大量文献调研基础上,综述了本课题组近年来用腈类与手性氨基醇作用,在不同物质的量的金属盐如氯化锌、乙酸铜和氯化钴等金属氯化物或金属乙酸盐作用下,一锅法一步合成系列噁唑啉金属配合物及应用研究进展。同时,对该方法在其他噁唑啉金属配合物合成及应用领域提出展望。 相似文献
6.
聚羧基乙酸及其共聚物 总被引:1,自引:0,他引:1
对聚羧基乙酸及其共聚物的合成方法,生物降解性,生物相容性,力学性能,共聚改性等方面的研究进展做了综述,并讨论了聚羟基乙酸类材料的医学应用现状及前景。 相似文献
7.
磺化聚氯乙烯的催化酯化作用 总被引:2,自引:0,他引:2
聚氯乙烯与氯磺酸反应合成了一种高分子催化剂,研究了它对羧酸和醇的酯化反应的催化活性,探讨了催化合成乙酸正丁酯的反应条件,并催化合成了乙酸、丙酸和丁酸的十一种酯,收率为82—92%。 相似文献
8.
9.
通过二乙三胺五乙酸的双N-羟基琥珀酰亚胺活性酯与含氨基的乳糖或D-半乳糖衍生物反应,合成了8种含有D-半乳糖基的二乙三胺五乙酸非离子型配体,并进一步合成了其钆(Ⅲ)配合物,配体及配合物的结构经IR,^1HNMR与元素分析表征,对配合物的体外驰豫性能和小鼠急性毒性作了初步研究,家兔在磁共振成像实验表明这种上类造影剂具有肝靶向的特性。 相似文献
10.
利用大孔阳离子交换树脂为催化剂,催化合成乙酸糖醇酯,丙酸糠醇酯,丁酸糠醇酯,乙酸四氢糠醇酯,丙酸四氢糠醇酯,丁酸四氢糠醇酯,对影响反应的诸因素进行了讨论。 相似文献
11.
The chemical reactions underlying the formation of a water based alkoxide sol gel process for lead zirconate titanate thin films using solutions of Ti and Zr alkoxides are outlined. Titanium isopropoxide and zirconium propoxide are chemically modified by acetic acid in order to use water as a solvent. The nature of the hydrolysis reactions in the presence of acetic acid is reviewed. It is shown that the formation of ions and charged polymeric species reduces their rates of condensation and aggregation. 相似文献
12.
13.
Hayashi Hiroaki Suzuki Hisao Kaneko Shoji 《Journal of Sol-Gel Science and Technology》1998,12(2):87-94
Chemical modification effect of acetic acid was examined to control the hydrolysis and following condensation reaction of zirconium alkoxide. When acetic acid was added to zirconium alkoxide solution, acetic acid coordinated to a zirconium alkoxide to form a stable bidentate chelating compound if molar ratio of acetic acid to zirconium alkoxide (here after abbreviated as RA) was less than two. In the case of simultaneous addition of acetic acid and water into a zirconium alkoxide solution, acetic acid immediately reacted with alkoxide. Water reacted with residual functional alkoxy groups to proceed the following condensation. Changing the degree of chelating the acetic acid to a zirconium alkoxide led to the control of the hydrolysis and condensation by decreasing the alkoxy groups of zirconium alkoxide. Polymeric transparent monolithic gels could be successfully prepared in the range from RA = 1 to RA = 1.5, and from RW = 1 to RW = 1.5 (here RW means molar ratio of water to zirconium alkoxide), respectively. 相似文献
14.
Acetic acid vapor-deposited on ultrathin noncrystalline ice (NCI) and polycrystalline ice (PCI) films (less than 6 nm thick) under ultrahigh vacuum conditions has been investigated by using Fourier Transform Infrared Reflection-Absorption Spectroscopy. Pristine acetic acid deposited at 123 K (on a copper support) appears as an amorphous solid, which undergoes an irreversible phase transformation to a more structurally ordered (polycrystalline) form upon annealing to 153 K. Acetic acid is found to adsorb on NCI and PCI films initially through hydrogen bonding between C=O and dangling OH (of ice), followed by the formation of multilayers at 123 K. Thermal evolution studies of a low exposure of acetic acid on the ultrathin NCI and PCI films show that acetic acid undergoes coevaporation with water likely as an acetic acid hydrate at 155 K, which continues until the entire ice film has been exhausted at 165 K. Above 165 K, the remaining acetic acid solid appears to evaporate without undergoing the phase transformation, in contrast to the case of a high acetic acid exposure. Coevaporation of acetic acid with water is also found to proceed at a faster rate than the subsequent evaporation of acetic acid, which is consistent with the weaker interactions observed in the H-bonded acetic acid hydrate than that in acetic acid solid. 相似文献
15.
The aim of this study was to investigate the changes in carbohydrate components and the crystalline structure in hemp bast
fibers by adding ethyl acetate to acetic acid/water pulping processes. It was found that ethyl acetate added to acetic acid/water
process had a positive effect on yield, viscosity and carbohydrate components in pulp. It was assumed that the delignification
ratio increased by adding ethyl acetate to aqueous acetic acid pulping. Xylose content in hemp bast fibers was affected more
negatively in the ethyl acetate/acetic acid/water process than in the acetic acid/water one. Crystallinity and crystallite
size were higher in pulp sample obtained by the acetic acid/water process without ethyl acetate. 相似文献
16.
醋酸胶片的片基材料醋酸纤维素酯水解产生的"醋酸综合症"是影像部门保存醋酸胶片过程中遇到的最大技术难题之一,目前还没有较好的治理方法,其在降解过程中释放出的醋酸严重影响胶片的耐久性,关于其物理性能变化及相关性的研究较少.本文通过模拟密闭环境中醋酸浓度的累积实验,系统地分析了醋酸在胶片降解过程中对胶片物理性能的影响.实验结果表明,醋酸环境会加速胶片的降解,且随着醋酸浓度的增加,胶片扭曲变形程度增加,胶片的降解程度(酸度)增加;抗张强度减弱,但耐折度增加;含湿量和胶片乳剂层面的亲水性增加,同时胶片的热稳定性变差. 相似文献
17.
E. V. Tarasova V. M. Chernyshev A. V. Chernysheva R. S. Abagyan 《Russian Journal of Applied Chemistry》2011,84(3):400-406
Fundamental thermodynamic and kinetic aspects of the reaction in which acetic acid guanyl hydrazide is formed from aminoguanidine and acetic acid in aqueous solutions at pH 0.6-1.5 and the kinetics of cyclization of acetic acid guanyl hydrazide hydrochloride to 5-amino-3-methyl-1,2,4-triazole hydrochloride in a melt were studied. Methods for synthesis of acetic acid guanyl hydrazide hydrochlorides and 5-amino-3-methyl-1,2,4-triazole hydrochloride were developed. 相似文献
18.
Johnson CM Tyrode E Baldelli S Rutland MW Leygraf C 《The journal of physical chemistry. B》2005,109(1):321-328
Aqueous acetic acid solutions have been studied by vibrational sum frequency spectroscopy (VSFS) in order to acquire molecular information about the liquid-gas interface. The concentration range 0-100% acetic acid has been studied in the CH/OH and the C-O/C=O regions, and in order to clarify peak assignments, experiments with deuterated acetic acid and water have also been performed. Throughout the whole concentration range, the acetic acid is proven to be protonated. It is explicitly shown that the structure of a water surface becomes disrupted even at small additions of acetic acid. Furthermore, the spectral evolution upon increasing the concentration of acetic acid is explained in terms of the different complexes of acetic acid molecules, such as the hydrated monomer, linear dimer, and cyclic dimer. In the C=O region, the hydrated monomer is concluded to give rise to the sum frequency (SF) signal, and in the CH region, the cyclic dimer contributes to the signal as well. The combination of results from the CH/OH and the C-O/C=O regions allows a thorough characterization of the behavior of the acetic acid molecules at the interface to be obtained. 相似文献
19.
20.
The Separation of Polyphenols by Isocratic Hydrogen Bond Adsorption Chromatography on a Cross-Linked 12% Agarose Gel 总被引:2,自引:0,他引:2
The highly cross-linked 12% agarose gel, Superose™ 12 HR 10/30 is shown to possess hydrogen bond acceptor properties suitable for the separation of polyphenolic solutes such as phenolic acids, flavonols and flavonoids. The separation is achieved isocratically in the presence of solvent mixtures of acetic acid and ethanol. The extent of hydrogen bond adsorption is reviewed based on data obtained from the elution behaviour of a variety of simple polyphenolic solutes including dihydroxybenzoic acids. 相似文献