scholarly journals Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation

2014 ◽  
Vol 10 ◽  
pp. 1817-1825 ◽  
Author(s):  
Carmen Martín ◽  
Arjan W Kleij
Keyword(s):  
Catalyst Concentration ◽  
Catalyst System ◽  
Bifunctional Catalyst ◽  
Cyclic Carbonates ◽  
First Order ◽  
Order Dependence ◽  
Carbonate Formation ◽  
Salen Complexes ◽  
Organic Carbonate ◽  
Binary Catalyst

Zn(salen) complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO2. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen)/NBu4I and a bifunctional system Zn(salpyr)·MeI with a built-in nucleophile. The latter system demonstrates an apparent second-order dependence on the bifunctional catalyst concentration and thus follows a different, bimetallic mechanism as opposed to the binary catalyst that is connected with a first-order dependence on the catalyst concentration and a monometallic mechanism.

CO-CATALYSIS IN FRIEDEL–CRAFTS REACTIONS: VI. POLYMERIZATION OF 2-BUTENE BY BORON FLUORIDE – METHANOL

1963 ◽  
Vol 41 (4) ◽  
pp. 932-936 ◽  
Author(s):  
H. R. Allcock ◽  
A. M. Eastham
Keyword(s):  
Molecular Weight ◽  
Catalyst Concentration ◽  
Ethylene Dichloride ◽  
Low Molecular Weight ◽  
Boron Fluoride ◽  
First Order ◽  
Order Dependence ◽  
Rate Of Polymerization ◽  
Cis And Trans

2-Butene is polymerized by boron fluoride and methanol in ethylene dichloride solution at ordinary temperatures to give very low molecular weight polymers. The rate of polymerization shows exactly the same dependence on catalyst concentration as did the rate of isomerization of the cis- and trans-2-butenes, i.e. first order both in free boron fluoride and in the boron fluoride – methanol complex. The polymerization, however, shows a first-order dependence in olefin over a concentration range where the isomerization is, experimentally, virtually independent of the olefin concentration.

scholarly journals Highly efficient conversion of CO2 to cyclic carbonates with a binary catalyst system in a microreactor: intensification of “electrophile–nucleophile” synergistic effect

RSC Advances ◽  
2018 ◽  
Vol 8 (68) ◽  
pp. 39182-39186 ◽  
Author(s):  
Ming-Ran Li ◽  
Ming-Chao Zhang ◽  
Tian-Jun Yue ◽  
Xiao-Bing Lu ◽  
Wei-Min Ren
Keyword(s):  
Synergistic Effect ◽  
Ammonium Salt ◽  
Coupling Reaction ◽  
Catalyst System ◽  
Cyclic Carbonates ◽  
Efficient Conversion ◽  
Highly Efficient ◽  
System P ◽  
Binary Catalyst

An intensification of the “electrophile–nucleophile” synergistic effect was achieved in a microreactor for the coupling reaction of CO2 and epoxides mediated by the binary Al complex/ternary ammonium salt catalyst system.

Polystyrene-Supported Phenol/DMAP: An Efficient Binary Catalyst System for CO2 Fixation to Give Cyclic Carbonates.

ChemInform ◽  
2007 ◽  
Vol 38 (43) ◽  
Author(s):  
Chao-Rong Qi ◽  
Huan-Feng Jiang ◽  
Zhao-Yang Wang ◽  
Bo Zou
Keyword(s):  
Co2 Fixation ◽  
Catalyst System ◽  
Cyclic Carbonates ◽  
Binary Catalyst

Polystyrene-supported Phenol/DMAP: an Efficient Binary Catalyst System for CO2 Fixation to Give Cyclic Carbonates

2007 ◽  
Vol 25 (7) ◽  
pp. 1051-1054 ◽  
Author(s):  
Chao-Rong Qi ◽  
Huan-Feng Jiang ◽  
Zhao-Yang Wang ◽  
Bo Zou
Keyword(s):  
Co2 Fixation ◽  
Catalyst System ◽  
Cyclic Carbonates ◽  
Binary Catalyst

Cooperative catalyst system for the synthesis of oleochemical cyclic carbonates from CO2and renewables

2016 ◽  
Vol 18 (13) ◽  
pp. 3775-3788 ◽  
Author(s):  
Nils Tenhumberg ◽  
Hendrik Büttner ◽  
Benjamin Schäffner ◽  
Daniela Kruse ◽  
Michael Blumenstein ◽  
...  
Keyword(s):  
Catalyst System ◽  
Cyclic Carbonates ◽  
Binary Catalyst

Taking Control!The binary catalyst system composed of MoO3and an organic phoshponium salt [Bu4P]X proved very efficient to produce oleochemical cyclic carbonates from renewables.

The effect of polymeric and model imidazolium halides on the rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid

1985 ◽  
Vol 50 (4) ◽  
pp. 845-853 ◽  
Author(s):  
Miloslav Šorm ◽  
Miloslav Procházka ◽  
Jaroslav Kálal
Keyword(s):  
Catalyst Concentration ◽  
Low Molecular Weight ◽  
Imidazolium Chloride ◽  
First Order ◽  
Nitrobenzoic Acid ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
Ethanol In Water ◽  
Direct Attack

The course of hydrolysis of an ester, 4-acetoxy-3-nitrobenzoic acid catalyzed with poly(1-methyl-3-allylimidazolium bromide) (IIa), poly[l-methyl-3-(2-propinyl)imidazolium chloride] (IIb) and poly[l-methyl-3-(2-methacryloyloxyethyl)imidazolium bromide] (IIc) in a 28.5% aqueous ethanol was investigated as a function of pH and compared with low-molecular weight models, viz., l-methyl-3-alkylimidazolium bromides (the alkyl group being methyl, propyl, and hexyl, resp). Polymers IIb, IIc possessed a higher activity at pH above 9, while the models were more active at a lower pH with a maximum at pH 7.67. The catalytic activity at the higher pH is attributed to an attack by the OH- group, while at the lower pH it is assigned to a direct attack of water on the substrate. The rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid is proportional to the catalyst concentration [IIc] and proceeds as a first-order reaction. The hydrolysis depends on the composition of the solvent and was highest at 28.5% (vol.) of ethanol in water. The hydrolysis of a neutral ester, 4-nitrophenyl acetate, was not accelerated by IIc.

scholarly journals Highly Efficient MOF Catalyst Systems for CO2 Conversion to Bis-Cyclic Carbonates as Building Blocks for NIPHUs (Non-Isocyanate Polyhydroxyurethanes) Synthesis

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 628
Author(s):  
Adolfo Benedito ◽  
Eider Acarreta ◽  
Enrique Giménez
Keyword(s):  
Molar Mass ◽  
Cycloaddition Reaction ◽  
Building Blocks ◽  
Catalyst System ◽  
Cyclic Carbonate ◽  
Ammonium Bromide ◽  
Cyclic Carbonates ◽  
High Molar Mass ◽  
Highly Efficient ◽  
Free Process

The present paper describes a greener sustainable route toward the synthesis of NIPHUs. We report a highly efficient solvent-free process to produce [4,4′-bi(1,3-dioxolane)]-2,2′-dione (BDC), involving CO2, as renewable feedstock, and bis-epoxide (1,3-butadiendiepoxide) using only metal–organic frameworks (MOFs) as catalysts and cetyltrimethyl-ammonium bromide (CTAB) as a co-catalyst. This synthetic procedure is evaluated in the context of reducing global emissions of waste CO2 and converting CO2 into useful chemical feedstocks. The reaction was carried out in a pressurized reactor at pressures of 30 bars and controlled temperatures of around 120–130 °C. This study examines how reaction parameters such as catalyst used, temperature, or reaction time can influence the molar mass, yield, or reactivity of BDC. High BDC reactivity is essential for producing high molar mass linear non-isocyanate polyhydroxyurethane (NIPHU) via melt-phase polyaddition with aliphatic diamines. The optimized Al-OH-fumarate catalyst system described in this paper exhibited a 78% GC-MS conversion for the desired cyclic carbonates, in the absence of a solvent and a 50 wt % chemically fixed CO2. The cycloaddition reaction could also be carried out in the absence of CTAB, although lower cyclic carbonate yields were observed.

scholarly journals KINETICS OF PALM OIL TRANSESTERIFICATION IN METHANOL WITH POTASSIUM HYDROXIDE AS A CATALYST

2010 ◽  
Vol 8 (2) ◽  
pp. 219-225
Author(s):  
Yoeswono Yoeswono ◽  
Triyono Triyono ◽  
Iqmal Tahir
Keyword(s):  
Activation Energy ◽  
Palm Oil ◽  
Rate Constants ◽  
Potassium Hydroxide ◽  
Catalyst Concentration ◽  
Time Interval ◽  
Pseudo First Order Reaction ◽  
Exponential Factor ◽  
Potassium Methoxide ◽  
First Order

A study on palm oil transesterification to evaluate the effect of some parameters in the reaction on the reaction kinetics has been carried out. Transesterification was started by preparing potassium methoxide from potassium hydroxide and methanol and then mixed it with the palm oil. An aliquot was taken at certain time interval during transesterification and poured into test tube filled with distilled water to stop the reaction immediately. The oil phase that separated from the glycerol phase by centrifugation was analyzed by 1H-NMR spectrometer to determine the percentage of methyl ester conversion. Temperature and catalyst concentration were varied in order to determine the reaction rate constants, activation energies, pre-exponential factors, and effective collisions. The results showed that palm oil transesterification in methanol with 0.5 and 1 % w/w KOH/palm oil catalyst concentration appeared to follow pseudo-first order reaction. The rate constants increase with temperature. After 13 min of reaction, More methyl esters were formed using KOH 1 % than using 0.5 % w/w KOH/palm oil catalyst concentration. The activation energy (Ea) and pre-exponential factor (A) for reaction using 1 % w/w KOH was lower than those using 0.5 % w/w KOH.   Keywords: palm oil, transesterification, catalyst, first order kinetics, activation energy, pre-exponential factor

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