Carbonylative Reduction of Nitrophenols to Aminophenols

1995 ◽  
Vol 60 (3) ◽  
pp. 514-520 ◽  
Author(s):  
Vendelín Macho ◽  
Milan Kučera ◽  
Milan Králik
Keyword(s):  
High Selectivity ◽  
Sulfur Compound ◽  
Initial Pressure ◽  
Molar Ratio ◽  
Reaction Proceeds ◽  
Basic Additive ◽  
Mechanism Of The Reaction

Two- or three-component catalysts composed of (i) sulfur or sulfur compound (H2S, CS2, COS, Na2S), (ii) basic additive (triethylamine, CH3ONa, Na2S), and usually (iii) vanadium(V) compounds (e.g. NH4VO3) were found to catalyze efficiently the reaction of CO + H2O with isomeric nitrophenols to give the corresponding aminophenols. The reaction proceeds smoothly at 398 and 483 K and initial pressure of 7 MPa, and its rate increases from 2- to 4-nitrophenol. The selectivity to aminophenols exceeding 96 per cent was obtained at the water to nitrophenol molar ratio higher than 5. The solvents such as methanol and dioxane ensured better contact of the reactants, which was necessary for achievement of such a high selectivity. The effectiveness of the sulfur components (based on the S content) is expressed by the following sequence: S : CS2 : Na2S : H2 S : COS = 1 : 1.2 : 2.5 : 10 : 11. The reaction takes place also under the reduced CO pressure to 0.1 - 0.35 MPa. Formation of side products and mechanism of the reaction are discussed.

scholarly journals Production of value-added chemicals from esterification of waste glycerol over MCM-41 supported catalysts

2019 ◽  
Vol 8 (1) ◽  
pp. 128-134 ◽  
Author(s):  
Emine Kaya Ekinci ◽  
Nuray Oktar
Keyword(s):  
Acetic Acid ◽  
High Selectivity ◽  
Supported Catalysts ◽  
Value Added ◽  
Mass Spectrometry Analysis ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Glycerol Conversion ◽  
Spectrometry Analysis ◽  
Mcm 41

Abstract A series of active and selective MCM-41 supported catalysts have been successfully prepared and used for bioderived glycerol esterification with acetic acid to produce fuel additives. In the synthesis of MCM-41, an acidic hydrothermal synthesis route was used, and silicotungstic acid (STA) and zirconia (ZrO2) were added to the catalyst structure by wet impregnation. X-ray diffraction, nitrogen adsorption-desorption methods, scanning electron microscopy with energy-dispersive spectroscopy, and inductively coupled plasma-mass spectrometry analysis were used for characterizations of the catalysts. Diffuse reflectance infrared Fourier transform spectroscopy analyses of pyridine-adsorbed catalysts owns Lewis and Brønsted acidity hosting in one, which promotes the esterification reaction of glycerol into glycerol esters with high selectivity. Esterification of glycerol reactions were performed at temperature intervals of 105°C–200°C, with an amount of catalyst equal to 0.5 g, and glycerol/acetic acid molar ratio of 1:6 in a stirred autoclave reactor operated batchwise. STA and ZrO2-impregnated MCM-41 catalysts showed better performance with a complete glycerol conversion and high selectivity to triacetin.

Studies on the Immobilized-Lipase-Catalyzed Esterification of Alkyl Oleates in Solvent-Free Systems

2013 ◽  
Vol 645 ◽  
pp. 19-23 ◽  
Author(s):  
Hui Zhong ◽  
Zheng Fang ◽  
Bao Hua Zou ◽  
Xin Li ◽  
Kai Guo
Keyword(s):  
Oleic Acid ◽  
Low Temperature ◽  
High Selectivity ◽  
Immobilized Lipase ◽  
Enzyme Concentration ◽  
Molar Ratio ◽  
High Yield ◽  
Secondary Alcohols ◽  
Tertiary Alcohols ◽  
Candida Sp

The esterification of oleic acid with alkyl alcohols in solv ent-free systems was catalyzed by an immobilized lipase from Candida sp . 99-125. The influence of several factors, including enzyme concentration, temperature, molar ratio between oleic acid and alkyl alcohols, and structure of alcohol was also investigated. The results indicated that the reactions catalyzed by lipase at 20 o C, in the presence of 3% (w/w) lipase, on the molar ratio of 1:1 between oleic acid and alcohols, afforded products in high yield. It showed high selectivity to primary and low selectivity to secondary alcohols and tertiary alcohols because of the sterically hindered effect. Methanol has certain toxicity on the activity of the lipase. The lipase from Candida sp. 99-125 was identified to be an effective catalyst in the esterification of alcohol and oleic acid at low temperature.

N-Heterocyclic Carbene-Catalyzed Synthesis of Ynones via C–H Alkynylation of Aldehydes with Alkynyliodonium Salts

2019 ◽  
Author(s):  
Adam A. Rajkiewicz ◽  
Natalia Wojciechowska ◽  
Marcin Kalek
Keyword(s):  
Density Functional ◽  
Bond Formation ◽  
Kinetic Studies ◽  
Density Functional Theory Calculations ◽  
Hypervalent Iodine ◽  
Functional Theory ◽  
Leaving Group ◽  
13C Labelling ◽  
Reaction Proceeds ◽  
Mechanism Of The Reaction

Alkynylation of aldehydes with alkynyl(aryl)iodonium salts catalyzed by an N-heterocyclic carbene (NHC) has been developed. The application of the organocatalyst and the hypervalent iodine group-transfer reagent allowed for metal-free C–H functionalization and C–C bond formation. The reaction proceeds under exceptionally mild conditions, at –40 ⁰C and in the presence of an amine base, providing access to an array of heteroaryl-propargyl ketones containing various substituents in good to excellent yields. The mechanism of the reaction was investigated by means of both experiments and density functional theory calculations. 13C-labelling and computations determined that the key alkynyl transfer step occurs via an unusual direct SN2 substitution of iodine-based leaving group by Breslow intermediate nucleophile at an acetylenic carbon. Moreover, kinetic studies revealed that the turnover-limiting step of the catalytic cycle is the generation of the Breslow intermediate, whereas the subsequent C–C bond-formation is a fast process. These results were fully reproduced and rationalized by the computed full free energy profile of the reaction, showing that the largest energy span is located between protonated NHC and the transition state for the carbene attack on the aldehyde substrate.<br>

scholarly journals Properties and mechanism of action of pyruvate, phosphate dikinase from leaves

1969 ◽  
Vol 114 (1) ◽  
pp. 117-125 ◽  
Author(s):  
T. J. Andrews ◽  
M. D. Hatch
Keyword(s):  
Mechanism Of Action ◽  
Sugar Cane ◽  
Initial Velocity ◽  
Isotope Exchange ◽  
Reverse Direction ◽  
Pyruvate Phosphate Dikinase ◽  
Reaction Proceeds ◽  
Michaelis Constants ◽  
Phosphate Groups ◽  
Mechanism Of The Reaction

1. Sugar-cane leaf pyruvate,Pi dikinase was prepared free of enzymes that would interfere with studies on the stoicheiometry and mechanism of the reaction it catalyses. The reaction was unequivocally shown to involve the conversion of equimolar amounts of pyruvate, ATP and Pi into phosphoenolpyruvate, AMP and PPi. 2. The purified enzyme was stable at pH8·3 only if stored at about 20° in the presence of Mg2+ and a thiol-reducing reagent, care being taken to prevent the oxidation of the thiol. 3. The apparent Michaelis constants for phosphoenolpyruvate and PPi were 0·11mm and 0·04mm respectively and that for AMP was less than 4μm. 4. At pH8·3 the initial velocity of the reaction was about 6 times as fast in the direction towards phosphoenolpyruvate synthesis as in the reverse direction. 5. With the exception of ATP, all the products of the reaction in both directions were inhibitory. 6. The phosphate groups of PPi were derived from Pi and from the terminal phosphate of ATP. 7. Isotope-exchange studies indicated that the reaction proceeds in the following steps: Enzyme+ATP+Pi ⇌ Enzyme–P+AMP+PPi Enzyme–P+pyruvate ⇌ Enzyme+phosphoenolpyruvate

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: II. ISOBUTANE

1938 ◽  
Vol 16b (8) ◽  
pp. 260-272 ◽  
Author(s):  
E. W. R. Steacie ◽  
I. E. Puddington
Keyword(s):  
Rate Constants ◽  
Pressure Range ◽  
Reaction Rate ◽  
High Pressures ◽  
Initial Pressure ◽  
First Order ◽  
Decomposition Reactions ◽  
Order Rate ◽  
Reaction Proceeds ◽  
Kinetics Of

The kinetics of the thermal decomposition of isobutane has been investigated over an initial pressure range of from 5 to 60 cm., and at temperatures from 522 to 582 °C. The initial first order rate constants at high pressures are given by[Formula: see text]The results are in general agreement with those obtained by previous investigators. The reaction rate falls off with diminishing pressure, and the first order rate constants in a given run diminish strongly as the reaction proceeds. This behavior is similar to that of n-butane.Analyses of the products of the reaction were made at various stages, temperatures, and initial pressures by low-temperature distillation in a still of the Podbielniak type. The initial products were found by extrapolation to be H2, 35; CH4, 14; C2H4, 0.9; C2H6, 0.9; C3H6, 14; and C4H8, 35%. The results are compared with those of other workers.

scholarly journals Selective Hydrogenation of Dodecanoic Acid to Dodecane-1-ol Catalyzed by Supported Bimetallic Ni-Sn Alloy

2018 ◽  
Vol 13 (2) ◽  
pp. 311 ◽  
Author(s):  
Rodiansono Rodiansono ◽  
Muhammad Iqbal Pratama ◽  
Maria Dewi Astuti ◽  
Abdullah Abdullah ◽  
Agung Nugroho ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Initial Pressure ◽  
Reaction Engineering ◽  
Hydrogen Gas ◽  
Molar Ratio ◽  
Dodecanoic Acid ◽  
N2 Adsorption ◽  
Bet Method ◽  
Alloy Catalysts ◽  
Autoclave Reactor

Selective hydrogenation of dodecanoic acid over supported bimetallic Ni-Sn alloy catalysts into dodecane-1-ol is demonstrated. Bimetallic nickel-tin supported on titanium oxide (Ni-Sn(1.5)/TiO2) and gamma-alumina (Ni-Sn(1.5)/g-Al2O3); 1.5 = Ni/Sn molar ratio) were synthesized via hydrothermal method in a sealed-Teflon autoclave reactor at 150 oC for 24 h, then followed by reducing with hydrogen gas at 400 oC for 1.5 h. The synthesized catalysts were characterized by means of XRD, IC-AES, N2-adsorption (BET method), H2-chemisorption, and NH3-TPD. Bimetallic Ni-Sn(1.5)/TiO2 catalyst was found to be effective for hydrogenation of dodecanoic acid (>99 % conversion) to dodecane-1-ol (93% yield) at 160 oC, 30 bar H2, and 20 h and the highest dodecane-1-ol (97 % yield) was obtained at initial pressure of H2, 50 bar. An increase of reaction temperature slightly enhanced the degree of hydrodeoxygenation of dodecanoic acid to produce dodecane over both Ni-Sn(1.5)/TiO2 and Ni-Sn(1.5)/g-Al2O3 catalysts. Copyright © 2018 BCREC Group. All rights reservedReceived: 26th November 2017; Revised: 24nd December 2017; Accepted: 24th January 2018; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Rodiansono, R. Pratama, M.I., Astuti, M.D., Abdullah, A., Nugroho, A., Susi, S. (2018). Selective Hydrogenation of Dodecanoic Acid to Dodecane-1-ol Catalyzed by Supported Bimetallic Ni-Sn Alloy. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 311-319 (doi:10.9767/bcrec.13.2.1790.311-319) 

Ir-Catalyzed Site Selective Borylation of 8-Arylquinolines

Synthesis ◽  
2021 ◽  
Author(s):  
Buddhadeb Chattopadhyay ◽  
Mirja Md Mahamudul Hassan ◽  
Md Emdadul Hoque ◽  
Sayan Dey ◽  
Saikat Guria ◽  
...  
Keyword(s):  
Functional Groups ◽  
Convenient Method ◽  
High Selectivity ◽  
Catalytic Amount ◽  
Excellent Yield ◽  
Reaction Proceeds ◽  
Site Selective ◽  
Excellent Selectivity

We report a convenient method for the highly site selective borylation of 8-arylquinoline. The reaction proceeds smoothly in presence of catalytic amount of [Ir(OMe)(cod)]2 and 2-phenylpyridine derived ligand using bis(pinacolato)diborane as the borylating agent. The reactions occur with high selectivity with many functional groups, providing a series of borylated 8-aryl quinolines with good to excellent yield and excellent selectivity. The borylated compounds formed in this method can be transformed to various important synthons using known transformations.

Darstellung und [1+4]-Cycloaddition von Methylthio-chlorophosphanen RP(Cl)SMe (R = Me, Et, Ph) / Preparation and [1+4]-Cycloaddition of Methylthio-chlorophosphanes RP(Cl)SMe (R = Me, Et, Ph)

1988 ◽  
Vol 43 (3) ◽  
pp. 257-260 ◽  
Author(s):  
Jörg Apitz ◽  
Joseph Grobe ◽  
Due Le Van
Keyword(s):  
Elemental Analysis ◽  
Molar Ratio ◽  
One Pot ◽  
Spectroscopic Investigations ◽  
Condensation Reactions ◽  
Reaction Proceeds ◽  
New Compounds

The methylthio-chlorophosphanes RP(Cl)SMe [R = Me (1). Et (2). Ph (3)] are prepared in good yields (62-65%) by condensation reactions of the corresponding dichlorophosphanes RPC12 with methanethiol in the presence of trimethylamine (molar ratio 1:1:1). 1 and 3 have been used to produce 3-phospholene sulfides in a one-pot process by reaction with 1,3-dienes at 70 to 100 °C. Reaction proceeds via [1+4]-cycloadducts, which in suitable cases can be isolated and used for the preparation of the corresponding 3-phospholene oxides. New compounds were characterized by elemental analysis and spectroscopic investigations (NMR. MS).

Catalytic activity of cupric oxide in addition reactions of alkyl cyanoacetates with 1-alkenes

1979 ◽  
Vol 44 (12) ◽  
pp. 3695-3704 ◽  
Author(s):  
Milan Hájek ◽  
Jaroslav Málek
Keyword(s):  
High Selectivity ◽  
Addition Reaction ◽  
Fast Rate ◽  
Cupric Oxide ◽  
Ethyl Cyanoacetate ◽  
Radical Mechanism ◽  
Addition Reactions ◽  
Free Radical Mechanism ◽  
Reaction Proceeds ◽  
High Yields

In the presence of cupric oxide as the catalyst, ethyl cyanoacetate reacts with 1-alkenes to form 1 : 1 adducts in high yields. The active catalytic component was found to be a soluble copper species generated in the absence of oxygen in 10-3 to 10-5 M concentrations by a partial dissolution of cupric oxide in ethyl cyanoacetate. The homogeneous catalytic reaction proceeds already at temperatures about 80 °C at a fast rate and with high selectivity. Results of inhibition experiments in the presence of α-naphthol and galvinoxyl support strongly the view on a free-radical mechanism of the addition reaction.

The effect of steric crowding on an E2 transition state

1976 ◽  
Vol 54 (14) ◽  
pp. 2339-2341 ◽  
Author(s):  
George Stanley Dyson ◽  
Peter James Smith
Keyword(s):  
Transition State ◽  
Isotope Effect ◽  
Nitrogen Isotope ◽  
Bond Rupture ◽  
Deuterium Isotope Effect ◽  
Steric Crowding ◽  
Reaction Proceeds ◽  
Hydrogen Deuterium ◽  
Nitrogen Bond ◽  
Mechanism Of The Reaction

The mechanism of the reaction of 9-(4-substituted benzyl)fluorene-9-trimethylammonium ions with ethoxide is a normal E2 process. The magnitude of the primary hydrogen–deuterium isotope effect at 60 °C increased with increasing electron-donating ability of the 4-substituent, i.e., 4.15, 5.10, 5.34, 5.65, 5.75, and 5.91 for the 4-CF3, 4-Br, 4-Cl, 4-H, 4-CH3, and 4-OCH3 substituents, respectively. The magnitude of the nitrogen isotope effect at 70 °C decreased with increased electron-donating power of the 4-substituent, i.e., [(k14/k15)–1]100 = 1.24, 0.95, 0.92, 0.91, and 0.80 for the 4-CF3, 4-F, 4-H, 4-CH3, and 4-OCH3 substituents, respectively. A small Hammett ρ value of +1.33 was observed for the reaction. It is concluded that the reaction proceeds via a transition state where the proton is more than one-half transferred to base. It is further concluded that for a reaction in which the 4-substituents decrease the rate, both carbon–hydrogen and carbon–nitrogen bond rupture is more advanced in the transition state. This variance with Hammond's postulate is discussed in the light of steric crowding at the transition state.

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