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1.
Difluoromethanesulfonic acid (1) readily reacts with P2O5 at room temperature to give difluoromethyl difluoromethanesulfonate (2) and SO2 in stead of the expected acid anhydride. If perfluorosulfonic acid (3) perfluorocarboxylic acid (5) or KI was added to this reaction mixture, difluoromethyl perfluorosulfonate (4), difluoromethyl perfluorocarboxylate (6) and HCF2I (7) was formed respectively in addition to 2. A similar result was obtained using POCl3 or SOCl2 instead of P2O5 as dehydrating agent. The mechanisms of the formation of difluorocarbene were discussed.  相似文献   

2.
A convenient and efficient one-pot N-alkylation of nucleobases from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of purine or pyrimidine nucleobase, TsIm, K2CO3, and triethylamine in refluxing DMF regioselectively furnishes the corresponding N-alkyl nucleobases in good yields. This methodology is highly efficient for various structurally diverse primary alcohols.  相似文献   

3.
A novel approach was achieved for growing citric acid towards polymer-like graphene quantum dots (PGQD) with high efficiency in the presence of sodium hydroxide as a base catalyst. This protocol is completely safe, simple, fast, and efficient by a bottom up strategy. Thermal treatment of a mixture containing citric acid with NaOH at 300 °C gave PGQD during 5 min. The reaction afforded a new heterogeneous catalyst, Pd/PdO/Fe3O4@PGQD, in the presence of Pd and Fe3O4. The magnetically recoverable catalyst showed high activity in the oxidation of alkylarenes and alcohols using H2O2 as a green oxidant at room temperature. Comparison of the results with previous reports showed the efficiency of the catalyst to have high turnover numbers in mild reaction conditions.  相似文献   

4.
Summary Ru/g-Al2O3 catalyzed the dehydrogenation of alcohols to carbonyl compounds without employing hydrogen acceptor. The catalyst was readily recovered from the reaction mixture and could be reused.  相似文献   

5.
Herein we report a novel magnetically recoverable lanthanum hydroxide nanoparticles for oxidative synthesis of nitriles directly from corresponding alcohols with ammonia as nitrogen source. The procedure for the preparation and characterization of La(OH)3/Fe3O4 magnetic nanoparticles were investigated and the scope and generality of the method was explored for a series of structurally diverse primary alcohols with electron‐donating and electron‐withdrawing groups. The best result was observed when 5 mol% of La with respect to the benzyl alcohol was used at reflux condition under O2 atmosphere. The La(OH)3/Fe3O4 magnetic nanoparticles could be easily isolated from the reaction mixture with an external magnet and reused at least 5 times without significant loss in activity.  相似文献   

6.
A catalyst based on immobilization of a molybdenum(VI) Schiff base complex on γ-Fe2O3 magnetic nanoparticles has been synthesized and characterized. This catalyst was employed for the selective oxidation of alcohols to the corresponding carbonyl compounds in EtOH/H2O2. The catalyst can be easily separated from the reaction mixture by decantation using an external magnet and reused efficiently in five subsequent reaction cycles without any significant decrease in activity or selectivity.  相似文献   

7.
Various primary alcohols, particularly benzylic alcohols, could be converted into the corresponding aromatic amides in good yields in a one-pot manner by treatment with molecular iodine in aq. NH3, followed by reaction with ∼30% aq H2O2. Similarly, various benzylic halides could be also converted into the corresponding aromatic amides in good yields in a one-pot manner by treatment with molecular iodine in aq NH3, followed by reaction with ∼30% aq H2O2. The present reactions involve the metal-free one-pot oxidative conversion of benzylic alcohols and benzylic halides into the corresponding aromatic amides, respectively.  相似文献   

8.
The limiting apparent molal adiabatic and isothermal compressibilities in aqueous solutions of alcohols and ethers at various temperatures have been determined by means of ultrasonic velocity measurements. The following compounds have been considered: secondary cyclic and open-chain alcohols (cyclopentanol, cyclohexanol, cycloheptanol, 2-butanol, 3-pentanol, 3-hexanol, 4-heptanol; cyclic ethers of the types (CH2)3On (n=1, 2, 3), (CH2)nO2 (n=3, 4, 5), and (CH2)nO (n=3, 4, 5); and the linear diethers dimethoxymethane, diethoxymethane, and 1,2-dimethoxyethane. The results indicate that both alcohols and ethers cause the water near the solute to become more resistant to pressure than the bulk. This is in agreement with the prediction of a mixture model for water.  相似文献   

9.
Measurement for a rate of reaction for about 30?min at a 5?min interval between KI and K2S2O8 aqueous solutions with conventional burette in industries and academics consumes about 3.375?g K2S2O8/250?mL?:?4.15?g KI/250?mL?:?11.6?mL (CH3COOH, glacial)/100?mL?:?1?g starch/10?mL?:?0.62?g Na2S2O3 (sodium thiosulphate)/250?mL?:?50?mL ice cold water. The number after the oblique in mL depicts an amount of aqueous solution where the amounts of chemicals in grams are dissolved. Similar determinations with econoburette reduced their amounts in 0.0675?g K2S2O8/5?mL?:?0.083?g KI/5?mL:?0.5?mL (CH3COOH, glacial)/5?mL?:?0.05?g starch/0.5?mL?:?0.025?g Na2S2O3/2?mL?:?2.5?mL ice cold water. The reduction in amounts is about 50 times, and similarly the time and operational efforts are reduced in the same proportion. The econoburette is a ‘green chemistry’ instrument which performs valuable titration with microlitre of substances. The micro level amount of titer and titrant consumed less time in performing a volumetric tititration and also prevented much use of materials. In general, after titration a significant quantity of indicators, additives, titer and titrant are consumed and drained out in a sink with the possibility of causing pollution. The econoburette reduces such wastage of materials by up to 90%, with high accuracy in results. The rate constant k?=?0.0431?sec?1?L–1?mol?1 remained fairly constant for successive measurements with time but with the conventional burette larger deviations were noted at 298.15 Kelvin temperature.  相似文献   

10.
In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one‐step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re‐used 8 times without significant loss of catalytic activity.  相似文献   

11.
Tertiary alcohols as well as primary and secondary benzylic alcohols react efficiently with nitriles to give the corresponding amides in good to excellent yields in the presence of P2O5/SiO2 (60% w/w).  相似文献   

12.
KF/Al2O3 acts as an efficient catalytic system for the synthesis of carboacyclic nucleosides via Michael addition of pyrimidine and purine nucleobases to α,β-unsaturated esters under solvent-free and microwave conditions. Using this method, the title compounds are produced in good to excellent yields and short reaction times.  相似文献   

13.
A rapid and regioselective preparation of homopropargyl alcohols was reported. In the presence of SnCl2C6HsMe3NBr and microwave irradiation, the mixture of tin-indium and propargyl bromide reacted quickly with aldehydes in aqueous media to produce the homopropargyl alcohols exclusively in high yields. For benzaldehydes bearing different substituents, electronic effect of the substituents affected the reaction, the electron-withdrawing groups promoting the reaction and the electron-donating groups impeding the reaction. The reactions of benzaldehydes bearing an ortho substituent group on the phenyl ring with propargyl bromide may yield a mixture of regioisomers (homopropargyl and homoallenyl alcohols) or a single homoallenic alcohol due to the steric effect.  相似文献   

14.
Drim-9(11)-en-8α-ol and drim-9(11)-en-8β-ol were synthesized in six steps from drimenol. Drimenol was oxidized by P2O5 and DMSO to drimenal, which isomerized with p-TsOH into isodrimenal. Isodrimenal was reduced by NaBH4 into isodrimenol, epoxidation of which by m-CPBA gave a mixture (3.4:1) of α- and β-epoxyisodrimenols. These reacted with tosyl chloride in Py to give a mixture of α- and β-epoxyisodrimenol tosylates. Treatment of the tosylate mixture with KI and then Ph3P produced a mixture of drim-9(11)-en-8α- and -8β-ols that was separated chromatographically. The overall yield was ∼26%.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 152–155, March–April, 2005.  相似文献   

15.
A study is made of the deamination of diethylenetriamine over acidalkali catalysts, i. e., kaolin and alumina with promoters. Promoters which raise the acidity of the catalyst, affect the formation of triethylene diamine favorably. Increasing the amount of additive increases the amount of triethylenediamine, and cuts the optimum temperature at which it is formed. On kaolin or Al2O3+15% B2O3, the yield of triethylenediamine amounts to 30% theory. Addition of MoO3 facilitates dehydrodeamination and hydrogenolysis of the diethylenetriamine. The optimum promoter for preparing pyrazine is MoO3 along with a small amount of acid oxides. On the Al2O3+5% MoO3+1% P2O5, the pyrazine yield is 27.5% theory. Triethylenediamine can be separated from mixtures of it with piperazine by azeotropic distillation with mxylene or a mixture of mesitylene and -memylnaphthalene.  相似文献   

16.
The reaction of easily available Morita–Baylis–Hillman (MBH) alcohols with AgSCF3 in the presence of n-Bu4NI and KI affords primary allylic SCF3 products in high yields and excellent regioselectivities. This regioselective dehydroxytrifluoromethylthiolation protocol could also be extended to propargylic alcohols for the preparation of the primary propargylic SCF3 products.  相似文献   

17.
A method for one-pot preparation of Julia-Kocienski sulfides and sulfones from alcohols and thiols is reported. A variety of primary alcohols were converted to the corresponding mesylates by methansulfonyl chloride and triethylamine in THF. After the reaction is complete, thiol (1 or 10) and either NaH or t-BuOK were added. The Julia-Kocienski sulfides 3, 9 and 11 were prepared by one-pot two steps procedure from alcohols in 76–96% yields (16 examples). Furthermore, after the sulfide formation, the reaction mixture was neutralized by p-toluenesulfonic acid and treated with H2O2 and ammonium molybdate in EtOH to give the Julia-Kocienski sulfones 4 in good yields except for trans-2-hexen-1-ol.  相似文献   

18.
The IR spectra of vapour from a Na3PO4, Na5P3O10 and Na2O-P2O5, mixture have been obtained in solid nitrogen at 12 K. The results suggest that it is possible to isolate both NaPO3 and NaPO2 when sodium tripolyphosphate and the Na2O-P2O5 mixture are vaporized. There was no evidence of the NaPO molecule, reported to be one of the most abundant vapour species in mass-spectrometric work on the vaporization of Na5P3O10.  相似文献   

19.
The reaction of adsorbed oxygen (Oads) with aliphatic alcohols n-C n H2n + 1OH with n = 2–5 is studied by the method of transients of open-circuit potential in combination with potentiodynamic pulses. It is shown that these alcohols react with Oads by a mechanism the same as for CH3OH. Kinetic parameters of these reactions are determined in ranges of high and medium surface coverages with Oads. These data together with analogous results obtained earlier for CH3OH were studied with the aim of elucidating how the length of the hydrocarbon chain affects the kinetics of interaction of alcohols with Oads. The complex variations of the reaction rate with n (with a maximum) are explained by several factors among which the energy of the C–H bond at α-carbon atom and the degree hydration of alcohols should be singled out.  相似文献   

20.
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