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191.
硫酸氢钠催化合成己酸异戊酯的研究 总被引:14,自引:0,他引:14
己酸异戊酯是应用最广泛的食用香料之一。通常它是在硫酸催化下由己酸和异戊醇酯化反应而得[1] ,硫酸虽然活性高 ,价廉 ,但选择性差 ,产品质量不好 ,设备腐蚀严重 ,同时产生大量废液 ,污染环境。已发现对甲苯磺酸、磺酸树脂、固体超酸、杂多酸、氯化铁以及过渡金属硫酸盐等均可作为酯化反应的优良催化剂[2~ 7] 。本文探讨了硫酸氢钠催化羧酸的酯化反应 ,结果发现它具有良好的催化性能 ,且后处理方便 ,无污染。1 实验部分在装有分水器、温度计和回流冷凝器的四颈烧瓶中 ,加入一定量分析纯的己酸、异戊醇、甲苯和催化剂硫酸氢钠 (NaHSO… 相似文献
192.
193.
The thermal decomposition of some M
2
I
HPO3 (M-Li, Na, K) phosphites under nitrogen atmosphere was investigated. A stepwise mechanism of thermal decomposition has been proposed.
Zusammenfassung Es wurde die thermische Zersetzung von Phosphiten M 2 I HPO3 (M-Li, Na, K) in Stickstoffatmosphere untersucht. Die Schritte des Mechanismus der thermischen Zersetzung wurden vorgeschlagen.相似文献
194.
195.
Ugo Caruso Antonella De Maria Barbara Panunzi Antonio Roviello 《Journal of polymer science. Part A, Polymer chemistry》2002,40(17):2987-2993
Two formulas of grafted polymers with metal‐containing chromophores, potentially suitable for second‐order nonlinear optics applications, are described. Two chromophores were obtained from a tridentate ligand coordinated to Cu(II) or Pd(II) ions. The organometallic chromophore fragments were grafted to poly(4‐vinylpyridine) by the pyridinic nitrogen of the host polymer. Some qualities displayed by the new metallated polymers are remarkable: (1) a high value of the first hyperpolarizability coefficient of the chromophores, (2) a high content of the grafted chromophore in the polymers (up to 60 wt %), (3) a considerable increase in the glass‐transition temperatures (up to 240 °C), (4) good thermal stability in air (ca. 280 °C), and (5) good optical transparency of the films. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2987–2993, 2002 相似文献
196.
Reed M. Izatt Gypzy C. Lindh Peter Huszthy Glen A. Clark R. L. Bruening Jerald S. Bradshaw James J. Christensen 《Journal of inclusion phenomena and macrocyclic chemistry》1989,7(5):501-509
The macrocycle-mediated fluxes of alkali, alkaline earth, and several transition metal cations have been determined and compared in a H2O-CH2Cl2-H2O liquid membrane system using four water-insoluble macrocycles containing a dialkylhydrogenphosphate moiety. Transport of alkali metal cations by these ligands was greatest from a source phase pH = 12 or above into an acid receiving phase (pH = 1.5). Very low fluxes were observed for the transport of the alkaline earth cations and all transition metal ions studied except Ag+ and Pb2+ which were transported reasonably well by these new macrocycles.Deceased: September 5, 1987. 相似文献
197.
198.
M. Bešter-Rogač M. Tomšič J. Barthel R. Neueder A. Apelblat 《Journal of solution chemistry》2002,31(1):1-18
Conductivity measurements of oxalic acid and neutral oxalates (disodium oxalate, dipotassium oxalate, dicesium, and diammonium oxalate) were performed on dilute aqueous solutions, c < 3 × 10–3 mol-dm–3, from 5 to 35°C. These data and those available from the literature were analyzed in terms of dissociation steps of oxalic acid, the Onsager conductivity equation for neutral oxalates, the Quint–Viallard conductivity equation for the acid, and the Debye–Hückel equation for activity coefficients, to give the limiting equivalent conductances of bioxalate anion ;(HC2O4
–) and oxalate anion (1/2C2O4
2–) and the corresponding dissociation constants K
1 and K
2. 相似文献
199.
Fourier transform infrared reflection-absorption spectroscopy (FT-IRAS) has been used to study the orientation and coordination of glycine, L-phenylalanine and L-histidine on gold and copper surfaces. It was found that glycine and L-histidine were weakly adsorbed (physisorbed) in the zwitterionic form on gold. The surface chemical bonding of L-histidine and L-phenylalanine to copper were chemical rather than physical by nature. Conclusive evidence was obtained for coordination to copper through both the amino-nitrogen and carboxylate-oxygen atoms. 相似文献
200.
Enthalpies of solution of sodium octanoate in water, 1-propanol and aqueous mixtures of 1-propanol, 1-butanol, 1-pentanol and 1-hexanol, and of the alcohols in aqueous solutions of sodium octanoate at various concentrations were determined calorimetrically at 35 °C. MostH(soln) values are exothermic and strongly dependent on the solute concentration. The main energetic factor governing the process of dissolution of the surfactant is associated with changes in the water structure caused by the presence of alcohol. That governing the process of the alcohol dissolution in surfactant solutions is due to the effect alcohols have on the CMC of the octanoate. There is no indication of the alcohol being either solubilized in the interior of the aqueous micelle, or becoming part of the micellar film.The solubility at 35 °C of sodium octanoate in water, 1-propanol and their mixtures has also been determined. 相似文献