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1.
Ketones and aldehydes are conveniently and rapidly reduced to the corresponding alcohols in good yields using sodium borohydride under sealed-tube microwave conditions in either 95% ethanol or water. In purely aqueous systems, highly aliphatic substrates are sluggish, but this can be overcome by introducing sodium dodecyl sulfate (SDS) at the critical micelle concentration. With a 2:1 substrate/borohydride ratio and a reaction temperature of 100 °C, reduction is typically complete within 1 min in 95% ethanol and 5 min in water/SDS. The methodology is well suited for parallel and combinatorial synthetic approaches. 相似文献
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硼氢化钠是一种温和、高选择性的亲核还原剂。一般它只能还原醛、酮和酰氯,而对其它功能团不起作用。因而其应用范围有一定的限制。据文献报道,某些金属卤化物能有效地提高硼氢化钠的还原性能[1]。复合还原剂硼氢化钠/三氯化铁已应用于将β-二烷基氨基共轭烯酮还原为相应的饱和γ-氨基醇[2]。本文研究了硼氢化钠/三氯化铁对亚砜的还原反应。 相似文献
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Yu-Feng Hu 《Journal of solution chemistry》1998,27(3):255-260
Using a method for determination of solubilities of nonelectrolytes in electrolyte solutions based on isopiestic equilibration and precise chemical analyses, we have measured and report the solubilities of mannitol in sodium chloride solutions. Our results are, in general, in good agreement with the data of Kelly et al. The method is described and its advantages discussed. 相似文献
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以NaOH溶液快速沉淀BiCI3溶液制备了BiO(OH),研究了BiO(OH)对NaBH4还原芳香族硝基化合物的催化性能,考察了NaBH4用量对反应的影响.结果表明,在温和条件下BiO(OH)具有很高的催化活性和选择性.NaBH4和芳香族硝基化合物的摩尔比为1.04:1,在甲醇中室温反应2 h,芳香族硝基化合物主要被还原为氧化偶氮苯类化合物,收率80.4%~96.9%.该催化剂重复使用5次后活性没有明显下降.于120℃再生后,其活性与新制备催化剂相当. 相似文献
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Overthepasttenyears ,thepursuitofsynthetictar getswithincreasingcomplexityhasresultedinthedevel opmentofreactionsthatemphasizechemo ,regio ,di astereo andenantioselectivity .1 4 Theadditionsoforganichalidetocarbonylcompounds ,promotedbyvariousmet alsandacidc… 相似文献
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双核金属钌膦酸配合物(NH_4)_3[Ru_2(hedp)_2]·2H_2O(hedp=羟基亚乙基二膦酸)在常温水溶性体系中,无需相转移催化剂,可以高效催化t-Bu OOH氧化各种醇类,包括一级醇、二级醇和长链醇。催化机理研究表明,双核金属钌膦酸配合物的[Ru~Ⅲ-Ru~Ⅱ]~(3-)单元与t-Bu OOH作用,可以形成含过氧键的Ru~Ⅲ-Ru~Ⅲ-OO~tBu过渡态,然后再对底物醇进行氧化。该机理得到实验印证,如发现酸抑制而碱催进该反应,紫外可见光谱表明Ru~Ⅲ-Ru~Ⅲ-OO~tBu的形成。 相似文献
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Zhengning Li Guizhi Pan Zhu Zheng Huilin Chen 《Reaction Kinetics and Catalysis Letters》2000,69(1):77-82
Allylation of 5-methylfurfural with allyl halide and zinc was performed by using quaternary ammonium and phosphonium salts as phase-transfer catalysts. The phosphonium salt showed higher activity than the ammonium salt. Excellent yields were obtained with both catalysts. 相似文献
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系统地研究了无溶剂条件下,H2O2为氧源,反应控制相转移催化剂[(C16H33(70%)+C18H37(30%))N(CH3)3]3[PW4O16]催化氯丙烯环氧化制环氧氯丙烷反应.结果表明,在氯丙烯/H2O2/催化剂(摩尔比)=400∶100∶1条件下,50~55℃反应3 h,环氧氯丙烷的收率为85~87%.在NaH2PO4存在下,催化剂循环使用5次,活性无明显降低,新鲜催化剂和回收催化剂的31P MAS NMR谱分析结果表明NaH2PO4对催化剂结构和组成具有稳定作用. 相似文献
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A symmetric tetradentate Schiff base ligand bis(3‐methoxysalicylidene)‐o‐phenylenediamine (H2L) was prepared. A series of transition metal complexes with this Schiff base ligand have been synthesized and structurally characterized by IR and elemental analysis. The catalysis for reduction of thionyl chloride was studied by means of constant resistance discharge. The result shows that [Mn(III)LCl(H2O)]CH3OH and [Co(II)HLCl(H2O)] have a good catalytic activity for the reduction of thionyl chloride, which improves the cell voltage, the rate of discharge, and the lifetime of Li/SOCl2 batteries. 相似文献
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聚合物硼氢阴离子还原剂的制备及其对酯的还原研究 总被引:3,自引:0,他引:3
氯型季我安盐型强碱性阴离子交换树脂711^#与硼氢化钾反应制得聚合物硼氢阴离子还原剂,树脂容量3.2mmol BH4/g。用于不同酯化合物的还原,操作简便,树脂可再生重复使用。 相似文献
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The catalytic oxidation of benzyl halides to aldehydes and ketones in aqueous media was studied under relatively mild reaction conditions by using phase-transfer catalyst combined with potassium nitrate and 10% aqueous potassium hydroxide solution. As a result, a simple high-yield procedure has been developed. 相似文献
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The standard molal potential differences (Em∘) have been determined for the cell: CdHgx(two phase) | CdCl2(m), H2O(1 − w), 2-butanol (w) | AgCl(s) | Ag(s) in aqueous mixtures of low mass fraction of 2-butanol (w2-butanol = 0.05, 0.10, and 0.15) by using the literature data for the stability constants of the chlorocadmium complexes and the present potentiometric data for this cell at five temperatures from (293.15 to 313.15) K and at 10 molalities of CdCl2 from (0.002 to 0.02) mol-kg−1. The resulting values of E∘m have been used to calculate the standard thermodynamic quantities (ΔrG∘, ΔrH∘, and ΔrS∘) for the cell reaction, the stoichiometric mean molal activity coefficients (γ±) of CdCl2, and the standard thermodynamic functions for CdCl2 transfer (Δt G∘, Δt H∘, and Δt S∘) from water to the examined aqueous mixtures of 2-butanol. The values obtained have been compared with the analogous literature data for aqueous mixtures of 2-butanone; standard thermodynamic quantities for transfer of CdCl2 and HBr from water to mixtures containing the same mass fraction of 2-butanol have also been compared. For both electrolytes, these quantities show analogous trends with the alcohol content. This transfer process is nonspontaneous and endothermic. Enthalpy and entropy are evidently influenced by structural changes. 相似文献
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An Approach to Disulfide Synthesis Promoted by Sulfonyl Chloride in Sodium Bicarbonate Aqueous Media
Huilong Xiao Jiuxi Chen Miaochang Liu Huayue Wu Jinchang Ding 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2553-2559
A mild and efficient protocol for the synthesis of disulfides in aqueous media using mercaptans promoted by sulfonyl chloride is reported. This reaction offers the advantages of mild reaction conditions, short reaction time, high yields, and simple operation. 相似文献
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《Analytical letters》2012,45(2):123-128
Abstract An automated system for the determination of arsenic, selenium, antimony, bismuth and tin is described. These elements and their compounds are reduced with sodium borohydride to the corresponding hydride. Sensitivity of the automated system is comparable and in most cases better than the manual technique. The automated method was found superior to the manual with respect to reproducibility and ease of operation. 相似文献
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Tiana Jovanovi Jadranka Miliki Nikola Cvjetianin Stevan Stojadinovi Biljana ljuki 《Electroanalysis》2020,32(8):1867-1874
Polarization curves and complex kinetics of oxygen reduction (ORR) and borohydride oxidation (BOR) reaction were evaluated at thin Au layer on Ti and TiO2 electrodes. TiO2 electrodes prepared included amorphous TiO2 (AM?TiO2) and anatase (A?TiO2). The electrodes structure and nanotube arrays morphology were observed by XRD and SEM, respectively. All electrodes show activity for both ORR and BOR. The use of Au layer over A?TiO2 produces the strongest synergistic effect for ORR with exchange of 3 electrons. On the other hand, the strongest effect for BOR was observed in case of Au/Ti. 相似文献
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丙醇-氯化钠双水相体系萃取分离铂、钯、铑、金中的铱及其吸收光谱分析研究 总被引:12,自引:0,他引:12
提出了一种丙醇-氯化钠双水相体系萃取铱的分离-吸收光谱分析方法,在HCl介质中基于铱生成三氯亚锡酸络阴离子动力学速率与铂、钯、铑、金差异使铱与铂、钯、铑、金分离,其后在KI介质中萃取铱使其与贱金属基体分离,研究了在丙醇萃取相中铱的吸收光谱分析,并应用于实际样品中铱的测定。 相似文献
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Since the content of thiophene in coking crude benzene is high, it is necessary to remove it from coking crude benzene for efficient utilization. In this study, an important intermediate, N,N-dimethyl-2-thiophenecarboxamide, was synthesized from thiophene and dimethylcarbamyl chloride. The influences of the dosages of dimethylcarbamyl chloride and ZnCl2 catalyst, reaction temperature and time on the removal rate were further explored based on the reaction kinetics.The structure of the target product was characterized by means of MS,NMR and 13C NMR.The removal rate of thiophene was 98.14% after the reaction for 2 h and thiophene was almost removed after the reaction for 3 h under the optimal reaction conditions [a molar ratio of n(thiophene):n(dimethylcarbamyl chioride):w(ZnCl2)=1:12:10,300 r/min, 318 K and 101.325 kPa].The acylation of thiophene with dimethylcarbamyl chloride was approximately in accord with the first order kinetic equation at 303-323K.The activation energy was 53.9850 kJ/mol and the pre-exponential factor was 1.4521×10^9 h^-1. 相似文献