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1.
Recent developments in the aerobic oxidation of alcohols 总被引:1,自引:0,他引:1
2.
高压电场作用下乙醇-水溶液体系变化红外光谱分析 总被引:1,自引:0,他引:1
本文报道了用红外光谱分析电磁场作用下乙醇 水溶液体系变化情况。分析结果表明 :当乙醇溶液受到 2 0kV·cm- 1 的交变电磁场处理 (5 0Hz)时 ,分子之间的氢键缔合先增大后减少 ;高乙醇含量溶液受到同样强度电场较长时间处理时 ,有乙醇发生氧化反应 ,从红外谱中可看到νCO 峰及ν(OH) (H2 O) 峰的出现 ;经处理后的溶液自然放置 7天再测定 ,其红外谱图基本保持不变。文中对各出现变化的峰进行了分析 ,并对其机理进行了推导 相似文献
3.
The gene encoding a versatile biocatalyst that shows high enantioselectivity for a variety of ketones, SCR (Saccharomyces cerevisiae carbonyl reductase), has been identified, cloned, and expressed in Escherichia coli. Two types of expression systems with high NADPH-regenerating capacities have been constructed. One is the tandem system, where the genes encoding SCR and GDH (glucose dehydrogenase) are located in the same plasmid, and the other is the two-plasmid system, where each of the SCR and GDH genes is located in separate plasmids that can coexist in one E. coli cell. Asymmetric reduction of ketones with the recombinant E. coli cells gave synthetically useful 20 alcohols, 11 of which were enantiomerically pure. The productivity of one of these products was as high as 41 g/L. 相似文献
4.
Matrix-Investigations on Monomeric Copper(I) Chloride and its Complexes with N2 and PN Ligands. IR Spectroscopic Results and ab-initio Calculation In solid argon the reaction of monomeric CuCl with N2 yields ClCuN2. On the basis of two absorptions in the ir-spectrum and their corresponding isotopic shifts (14/15N) and with the help of a normal coordinate analysis, linearity of the molecule has been deduced. These results are confirmed by large scale ab-initio Calculations (CPF, MP2). Reaction of monomeric CuCl with molecular PN under matrix condition is shown to give rise to new absorptions in the IR spectrum which arev assigned to a linear molecule ClCuNP. 相似文献
5.
Preparation and Molecular Structures of Oligofunctional Dirhenium Carbonyl Derivatives from Dirhenium Nonacarbonylphosphane Starting with dirheniumdecacarbonyl, one CO-Ligand was eliminated oxidatively and substituted by the labile acetonitrile ligand. As an intermediate eq-Re2(CO)9NCCH3 was received. The reaction of this labilised carbonyl with tris(trimethylsilyl)phosphine and subsequent methanolysis gave ax-Re2(CO)9PH3, which was isolated and characterized for the first time. Photochemical and thermal reaction of ax-Re2(CO)9PH3 led to the new bi- and trinuclear complexes Re2(μ-H)(μ3-PHRe(CO)5)(CO)8, Re2(μ-PH2)2(CO)8 and Re2(μ-H) · (μ-PH2)(CO)8, which were characterized by IR-, 1H- and 31P-NMR spectroscopy. The structures of ax-Re2(CO)9PH3, Re2(μ-H)(μ3-PHRe(CO)5)(CO)8 and Re2(μ-PH2)2(CO)8 were confirmed by single-crystal X-ray analysis. ax-Re2(CO)9PH3 has a very short Re? P bond length of 228(2) pm. 相似文献
6.
Glucose, maltose, sucrose, lactose, ethanol and urea concentrations were monitored simultaneously during the cultivation of Escherichia coli and Saccharomyces cerevisiae by means of enzyme field effect transistors (EnFETs) applying glucose dehydrogenase (GDH), maltase (MAL)/GDH, invertase (INV)/GDH, β-galactosidase (β-GAL)/galactosedehydrogenase (GALDH), alcoholdehydrogenase (ADH)/aldehydedehydrogenase (ALDH), and urease. These enzymes were (co)immobilized on the pH sensitive gates of an eight-FET array. The FET array was integrated in a commercial FIA system. 相似文献
7.
微波常压法合成水杨酸酯 总被引:15,自引:0,他引:15
在浓硫酸催化下,采用微波常压法由水杨酸分别与正丁醇、异丁醇、正戊醇和异戊醇反应合成相应的水杨酸酯。结果表明:当水杨酸:醇:H2SO4=1:5.5:0.3(摩尔比)时,采用560W微波辐射22min,水杨酸酯的产率可达88.7% ̄96.4%,反应速度至少是常规反应的14倍。 相似文献
8.
9.
Summary The novel theoretical scheme IMOMM, integrating ab initio and molecular mechanics contributions in a single geometry optimization process, is applied to the structural determination of different [OsO4(NR3)] (NR3 = bulky chiral alkaloid derivative) species closely related to active catalysts for the asymmetric dihydroxylation of olefins. Computed values compare in a satisfactory way with available X-ray data, the relationship between the Os-N distance and the nature of the NR3, ligand being properly reproduced. The computational scheme allows the separate quantification of electronic and steric effects, as well as the identification of the specific steric repulsions responsible for the difference. 相似文献
10.
Mohammad H. Alizadeh Toktam Kermani Reza Tayebee 《Monatshefte für Chemie / Chemical Monthly》2007,138(2):165-170
Summary. Esterifications of acetic acid with some linear, secondary, tertiary, and benzylic alcohols mediated by catalytic amounts
of Keggin, Wells–Dawson, and Preyssler type heteropolyacids were carried out under reflux at mild reaction conditions with good to excellent yields. Among the examined
catalysts, H3PW12O40 and H14NaP5W30O110 revealed better results than other heteropolyacids. This work was performed with the aim of simplifying the esterification
process by omitting any solvents and mineral acid catalysts. Easy work-up, low cost, and acidic waste reduction, which are
all important features from the environmental and economical points of view, are distinct aspects of this protocol. Heteropolyacid
catalysts could be separated after a simple work-up and reused for several times. 相似文献