Revisiting Glycerol Esterification with Acetic Acid over Amberlyst-35 via Statistically Designed Experiments: Overcoming Transport Limitations

2019 ◽  
Author(s):  
Víctor Gabriel Baldovino Medrano ◽  
Karen V. Caballero ◽  
Hernando Guerrero-Amaya
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Batch Reactor ◽  
Catalyst Particle ◽  
Experimental Designs ◽  
Particle Sizes ◽  
Turnover Rates ◽  
Designed Experiments ◽  
Different Temperatures ◽  
Glycerol Esterification

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

Revisiting Glycerol Esterification with Acetic Acid over Amberlyst-35 via Statistically Designed Experiments: Overcoming Transport Limitations

2019 ◽  
Author(s):  
Víctor Gabriel Baldovino Medrano ◽  
Karen V. Caballero ◽  
Hernando Guerrero-Amaya
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Batch Reactor ◽  
Catalyst Particle ◽  
Experimental Designs ◽  
Particle Sizes ◽  
Turnover Rates ◽  
Designed Experiments ◽  
Different Temperatures ◽  
Glycerol Esterification

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

Production of iso-Amyl Acetate: Heterogeneous Kinetics and Techno-feasibility Evaluation for Catalytic Distillation

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
B. Saha ◽  
A. Alqahtani ◽  
H.T.R. Teo
Keyword(s):  
Acetic Acid ◽  
Kinetic Data ◽  
Batch Reactor ◽  
Value Added ◽  
Catalyst Particle ◽  
Amyl Alcohol ◽  
Amyl Acetate ◽  
Molar Ratio ◽  
Heterogeneous Kinetics ◽  
Esterification Reactions

Esterification reactions are typically equilibrium limited, and face challenges with product purification. They are carried out commercially using either large excess of one of the reactants, or by removing one of the products continuously in a reactive distillation column (RDC). In the present work, we studied the kinetics of esterification reactions of dilute acetic acid with iso-amyl alcohol to produce a value added ester (iso-amyl acetate) using ion-exchange resins, Purolite® CT-175 and CT-275 as catalysts in a batch reactor. The effect of agitation speed, catalyst particle size, reaction temperature, acetic acid concentration, acetic acid to iso-amyl alcohol molar ratio and catalyst loadings were investigated to optimise the reaction conditions. The non-ideality of each species in the reacting mixture was accounted for by using the activity coefficient via the use of the UNIFAC group contribution method. The kinetic data were correlated with Langmuir-Hinshelwood-Hougen-Watson (LHHW) and Eley-Rideal (E-R) models. The detailed kinetic data and a reliable rate expression for the esterification of acetic acid with an aliphatic alcohol (iso-amyl alcohol) would be useful for the simulation and design of an RDC for removing dilute acetic acid from aqueous streams. Another objective of this work was to evaluate the techno-feasibility of this operation through a systematic procedure of residue curve map (RCM). RCM gives a design engineer an idea of the existence of any separation boundaries imposed by the singular points corresponding to the reactive or kinetic azeotropes and thereby provide an insight into the feasibility of the desired operation. In the present study, RCM was generated for the quaternary system (acetic acid - iso-amyl alcohol - iso-amyl acetate - water) under different conditions to work out the feasibility of the operation. This map also suggests possible column sequencing or configurations to achieve a desired duty in an RDC.

scholarly journals Kinetics and Mechanism of the Change of the 4-Nitrobenzylthio-System into 4,4′-Diformylazoxybenzene in Alkaline Dioxane-Water Media

1985 ◽  
Vol 40 (11) ◽  
pp. 1128-1132
Author(s):  
Y. Riad ◽  
Adel N. Asaad ◽  
G.-A. S. Gohar ◽  
A. A. Abdallah
Keyword(s):  
Acetic Acid ◽  
Sodium Hydroxide ◽  
Rate Constants ◽  
Main Product ◽  
Reaction Medium ◽  
Aqueous Dioxane ◽  
Proton Abstraction ◽  
First Order ◽  
Water Media ◽  
Different Temperatures

Sodium hydroxide reacts with α -(4-nitrobenzylthio)-acetic acid in aqueous-dioxane media to give 4,4'-diformylazoxybenzene as the main product besides 4,4'-dicarboxyazoxybenzene and a nitrone acid. This reaction was kinetically studied in presence of excess of alkali in different dioxane-water media at different temperatures. It started by a fast reversible a-proton abstraction step followed by two consecutive irreversible first-order steps forming two intermediates (α -hydroxy, 4-nitrosobenzylthio)-acetic acid and 4-nitrosobenzaldehyde. The latter underwent a Cannizzaro's reaction, the products of which changed in the reaction medium into 4,4'-diformylazoxybenzene and 4,4'-dicarboxyazoxybenzene. The rate constants and the thermodynamic parameters of the two consecutive steps were calculated and discussed. A mechanism was put forward for the formation of the nitrone acid.Other six 4-nitrobenzyl, aryl sulphides were qualitatively studied and they gave mainly 4,4'-diformylazoxybenzene beside 4,4'-dicarboxyazoxybenzene or its corresponding azo acid.

α-DEUTERIUM KINETIC ISOTOPE EFFECTS IN SOLVOLYSES OF endo-NORBORNYL p-BROMOBENZENESULFONATE

1965 ◽  
Vol 43 (8) ◽  
pp. 2254-2258 ◽  
Author(s):  
C. C. Lee ◽  
Edward W. C. Wong
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Aqueous Dioxane ◽  
Kinetic Isotope ◽  
Different Temperatures

endo-Norbornyl-2-d p-bromobenzenesulfonate was synthesized and the isotope effects, as measured by kH/kD, were determined over a range of temperatures for solvolyses in 30% water – 70% dioxane, acetic acid, and formic acid. Values of kH/kD are of the order of 1.20. The data appear to indicate slightly higher isotope effects as the solvents are changed from aqueous dioxane to acetic acid to formic acid, as well as somewhat higher isotope effects at lower temperatures. Possible mechanistic implications of these results are presented. Relative titrimetric acetolysis rates, kexo/kendo, at different temperatures, and enthalpies and entropies of activation for these acetolyses are evaluated and discussed.

scholarly journals Influence of Bio-Oil Phospholipid on the Hydrodeoxygenation Activity of NiMoS/Al2O3 Catalyst

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 418 ◽  
Author(s):  
Muhammad Abdus Salam ◽  
Derek Creaser ◽  
Prakhar Arora ◽  
Stefanie Tamm ◽  
Eva Lind Grennfelt ◽  
...  
Keyword(s):  
Active Sites ◽  
Batch Reactor ◽  
Active Phase ◽  
Aluminum Phosphate ◽  
Spent Catalyst ◽  
Bio Oil ◽  
Pore Blockage ◽  
Sulfided Catalyst ◽  
High Degree

Hydrodeoxygenation (HDO) activity of a typical hydrotreating catalyst, sulfided NiMo/γ-Al2O3 for deoxygenation of a fatty acid has been explored in a batch reactor at 54 bar and 320 °C in the presence of contaminants, like phospholipids, which are known to be present in renewable feeds. Oleic acid was used for the investigation. Freshly sulfided catalyst showed a high degree of deoxygenation activity; products were predominantly composed of alkanes (C17 and C18). Experiments with a major phospholipid showed that activity for C17 was greatly reduced while activity to C18 was not altered significantly in the studied conditions. Characterization of the spent catalyst revealed the formation of aluminum phosphate (AlPO4), which affects the active phase dispersion, blocks the active sites, and causes pore blockage. In addition, choline, formed from the decomposition of phospholipid, partially contributes to the observed deactivation. Furthermore, a direct correlation was observed in the accumulation of coke on the catalyst and the amount of phospholipid introduced in the feed. We therefore propose that the reason for the increased deactivation is due to the dual effects of an irreversible change in phase to aluminum phosphate and the formation of choline.

scholarly journals Probing the Catalytic Efficiency of Supported Heteropoly Acids for Esterification: Effect of Weak Catalyst Support Interactions

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Alsalme ◽  
Aliyah A. Alsharif ◽  
Hamda Al-Enizi ◽  
Mujeeb Khan ◽  
Saad G. Alshammari ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Catalyst Support ◽  
Supported Catalyst ◽  
Catalytic Efficiency ◽  
Biodiesel Production ◽  
Effect Of Temperature ◽  
Heteropoly Acids ◽  
Catalyst Loading ◽  
Esterification Activity

Supported heteropoly acids are an interesting class of solid acid catalysts which possess flexible structure and super acidic properties essentially required for the oil-based biodiesel production. In this study, a series of catalysts containing 25 wt.% of heteropolytungstate (HPW) supported on various clays or SiO2 were prepared, and their catalytic efficiency was evaluated for esterification of acetic acid with heptanol. The as-prepared catalysts were characterized by various techniques including FT-IR spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and BET. The catalytic efficiency of both bulk and supported HPW catalysts for the esterification activity strongly depends on the type of support and amount of catalyst; the bulk HPW catalyst and the catalyst supported by kaolinite with 25 wt.% of HPW exhibited highest activity. In order to study the effect of temperature on conversion, all the catalysts were subjected to different reaction temperatures. It was revealed that esterification activity of both bulk and supported HPW catalysts strongly depends upon the temperature variations of the reaction. Besides, the effect of leaching of active sites on the catalysts performance for biodiesel production was also evaluated by inductively coupled plasma studies (ICP). The kaolinite-supported catalyst (25% HPW/kaolinite) demonstrated higher amount of leaching which is also confirmed by the significant decrease in its catalytic activity when it is used for the second time. However, the higher activity demonstrated by HPW/kaolinite maybe because of some homogeneous reaction indicating a weak catalyst support interaction (WCSI) resulting in the leaching of the catalyst during the test. Furthermore, the effects of other reaction variables such as catalyst loading and reaction time on the conversion of acetic acid were also studied.

Microstructure and Properties of Nanosemicrystalline Si3N4 Ceramics with Doped Sintering Additives: Part II. Phase Transformation and Microstructural Control

1998 ◽  
Vol 13 (9) ◽  
pp. 2588-2596 ◽  
Author(s):  
K. H. Ryu ◽  
J-M. Yang
Keyword(s):  
Electron Microscopy ◽  
Pressureless Sintering ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Additives ◽  
Different Temperatures ◽  
Si3n4 Ceramics ◽  
Scanning Electron ◽  
Microstructural Control

The low temperature pressureless sintering of a nanosized Si3N4 powder with doped sintering additives was investigated. The microstructural evolution during sintering at different temperatures was analyzed using x-ray diffraction and scanning electron microscopy. The effect of using nanosized Si3N4 powder as a catalyst to accelerate the α→β–Si3N4 transformation of a commercial Si3N4 powder with larger particle sizes was also investigated. Finally, two stage sintering was used to study the feasibility of controlling the microstructure and the mechanical properties of the nanosized silicon nitride.

Aqueous phase conversion of CO2 into acetic acid over thermally transformed MIL-88B

2021 ◽  
Author(s):  
Waqar Ahmad ◽  
Paramita Koley ◽  
Swarit Dwivedi ◽  
Abhijit Shrotri ◽  
Akshat Tanksale
Keyword(s):  
Acetic Acid ◽  
Aqueous Phase ◽  
Carbon Emissions ◽  
Active Sites ◽  
Catalyst Recycling ◽  
Efficient Catalyst ◽  
Co Catalyst ◽  
Net Zero ◽  
Significant Difference ◽  
Zero Carbon

Abstract Sustainable production of acetic acid (AA) is a high priority due to its high global manufacturing capacity and numerous applications. Currently it is predominantly synthesized via carbonylation of methanol, in which both the reactants are fossil-derived. CO2 transformation into AA is highly desirable to achieve net zero carbon emissions, but significant challenges remain to achieve this efficiently. Herein, we report a heterogeneous catalyst, thermally transformed MIL-88B with Fe0 and Fe3O4 dual active sites, for highly selective AA formation via methanol hydrocarboxylation. This efficient catalyst showed high AA yield (590.1 mmol/gcat.L) with 81.7% selectivity at 150°C in aqueous phase using LiI as a co-catalyst. The reaction is believed to proceed via formic acid intermediate. No significant difference in AA yield and selectivity was noticed during catalyst recycling study up to five cycles. This work scalable and industrially relevant for CO2 utilisation to reduce carbon emissions, especially if green methanol and green hydrogen are used.

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