scholarly journals Silica Sulphuric Acid Catalyzed Fischer Esterification Reaction under Solventless Condition: A Novel Green Chemical Reaction

2011 ◽  
Vol 1 (1) ◽  
pp. 28-36 ◽  
Author(s):  
A. Rajendran
Keyword(s):  
Sulphuric Acid ◽  
Chemical Reaction ◽  
Esterification Reaction ◽  
Acid Catalyzed ◽  
Fischer Esterification

Solvolysis kinetics and mechanism of substituted 3-acetyl-1,3-diphenyltriazenes in acid medium; Kinetic acidity function

1987 ◽  
Vol 52 (9) ◽  
pp. 2212-2216
Author(s):  
Oldřich Pytela ◽  
Martin Kaska ◽  
Miroslav Ludwig ◽  
Miroslav Večeřa
Keyword(s):  
Acid Medium ◽  
Sulphuric Acid ◽  
Rate Constants ◽  
Decomposition Kinetics ◽  
Acidity Function ◽  
Hammett Equation ◽  
Kinetic Acidity ◽  
Reaction Constant ◽  
Acid Catalyzed ◽  
Catalytic Rate

The decomposition kinetics has been measured of fourteen 3-acetyl-1,3-bis(subst. phenyl)triazenes in 40% (v/v) ethanol and sulphuric acid. The kinetic acidity function and catalytic rate constants have been determined from the rate constants observed. Mechanism has been suggested for the general acid-catalyzed solvolysis from comparison of the course of the kinetic acidity function and H0 function and from the reaction constant of the Hammett equation.

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Gianluca Marcotullio ◽  
Miguel A. Tavares Cardoso ◽  
Wiebren De Jong ◽  
Ad H.M. Verkooijen
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Reaction Products ◽  
Arrhenius Law ◽  
Exponential Factor ◽  
Oil Derivatives ◽  
Destruction Kinetics ◽  
Acid Catalyzed ◽  
Effects Of Temperature

The interest for furfural has increased in the last years due to its potential for competing with oil derivatives as platform chemical. In addition, furfural, derived from C5 sugars, can play a key role in the valorization of the hemicellulose contained in biomass when considering the development of a modern biorefinery concept. The development of such new and competitive biorefinery processes must be based on accurate kinetic data for the reactions involving furfural in the conditions used for its production.This work addresses the determination of furfural destruction kinetics in aqueous acidic environment, using sulphuric acid as catalyst, in the temperature range 150 - 200°C, acid concentration range 36.4 - 145.5 mM and furfural initial concentration between 60.4 and 72.5 mM. These studies were carried out using a recently built lab-scale titanium reactor that enables liquid phase reactions in a relatively broad range of conditions.The obtained results show that destruction of furfural follows first-order reaction kinetics within the range of temperature and acid concentration evaluated. Moreover, the proposed kinetic model takes into account the effects of temperature and acid dilution on the ions activity, and thus H3O+, by using the electrolyte Non-Random Two-Liquid (eNRTL) model. By using this approach, the rate constant dependence on temperature could be described by the Arrhenius law and thus the activation energy could be estimated as being 125.1 [kJ/mol] and the pre-exponential factor 3.71•1011[s-1]. Separation of different reaction products was achieved by means of HPLC, these products were not yet completely identified. Contrarily to what is reported in previous works, formic acid formation from furfural under the tested conditions can be regarded as playing a far less pronounced role than suggested before.

scholarly journals Preparation of Biodiesel From Karanja (Pongamia Pinnata) Oil

2017 ◽  
Vol 29 (1) ◽  
pp. 24-28
Author(s):  
M Rakib Uddin ◽  
Kaniz Ferdous ◽  
Sukanta Kumar Mondal ◽  
Maksudur R Khan ◽  
MA Islam
Keyword(s):  
Chemical Engineering ◽  
Calorific Value ◽  
Clean Energy ◽  
Pongamia Pinnata ◽  
Esterification Reaction ◽  
Biodiesel Fuel ◽  
Step Method ◽  
Acid Catalyzed ◽  
Karanja Oil ◽  
Conventional Diesel Fuel

Biodiesel is a biodegradable, sustainable and clean energy has worldwide attracted renewed and growing interest in topical years, chiefly due to development in biodiesel fuel and ecological pressures which include climatic changes. In this paper, karanja (pongamia pinnata) seed has been studied as a potential source for biodiesel preparation. Karanja oil is extracted from the seed by different methods. Oil properties have been measured by standard methods. Acid catalyzed transesterification, acid catalyzed two-step method and three-step method have been studied for biodiesel preparation from karanja oil. In the three-step method, the first step is saponification followed by acidification to produce free fatty acid (FFA) and finally esterification of FFA to produce biodiesel. In saponification, acidification and esterification reaction, the reaction parameters were optimized. Silica gel was used in both transesterification and esterification to adsorb water, produced in the reaction hence increase the reaction rate. Properties of biodiesel such as specific gravity, FFA, Viscosity, saponification value, iodine value, cloud point, pour point, flash point, cetane index, calorific value etc are measured and compared to conventional diesel fuel and standard biodiesel.Journal of Chemical Engineering, Vol. 29, No. 1, 2017: 24-28

scholarly journals Group 13 Lewis Acid Catalyzed Synthesis of Cu2O Nanocrystals via Hydroxide Transmetallation

2021 ◽  
Author(s):  
Noah Gibson ◽  
Alexandria R. C. Bredar ◽  
Byron Farnum
Keyword(s):  
Oleyl Alcohol ◽  
Copper Ions ◽  
Colloidal Synthesis ◽  
Esterification Reaction ◽  
Group 13 ◽  
Oleyl Oleate ◽  
Acid Catalyzed ◽  
Uv Visible ◽  
Continuous Injection ◽  
Injection Procedure

The colloidal synthesis of metal oxide nanocrystals (NCs) in oleyl alcohol requires the metal to catalyze an esterification reaction with oleic acid to produce oleyl oleate ester and M-OH monomers, which then condense to form MxOy solids. Here we show that the synthesis of Cu2O NCs by this method is limited by the catalytic ability of copper to drive esterification and thus produce Cu+ -OH monomers. However, inclusion of 1-15 mol% of a group 13 cation (Al3+, Ga3+ , or In3+) results in increased yields for the consumption of copper ions toward Cu2O formation and exhibits size/morphology control based on the nature of M3+ . Using a continuous-injection procedure where the copper precursor (Cu2+ -oleate) and catalyst (M3+ -oleate) are injected into oleyl alcohol at a controlled rate, we are able to monitor the reactivity of the precursor and M3+ catalyst using UV-visible and FTIR absorbance spectroscopies. These time-dependent measurements clearly show that M3+ catalysts drive esterification to produce M3+ -OH species, which then undergo transmetallation of hydroxide ligands to generate Cu+ -OH monomers required for Cu2O condensation. Ga3+ is found to be the “goldilocks” catalyst, producing NCs with the smallest size and a distinct cubic morphology not observed for any other group 13 metal. This is believed to be due to rapid transmetallation kinetics between Ga3+ -OH and Cu + -oleate. These studies introduce a new mechanism for the synthesis of metal oxides where inherent catalysis by the parent metal (i.e. copper) can be circumvented with the use of a secondary catalyst to generate -OH ligands.

Kinetic acidity function and solvolysis of 3-hydroxy-1,3-diphenyltriazenes

1986 ◽  
Vol 51 (3) ◽  
pp. 564-572 ◽  
Author(s):  
Oldřich Pytela ◽  
Stanislava Štumrová ◽  
Miroslav Ludwig ◽  
Miroslav Večeřa
Keyword(s):  
Sulphuric Acid ◽  
Substituent Effects ◽  
Acidity Function ◽  
Kinetic Acidity ◽  
Acid Catalyzed ◽  
Kinetics Of

Ten 3-hydroxy-1-(X-phenyl)-3-phenyltriazines have been synthesized, and kinetics of their solvolysis have been measured in 40% (v/v) ethanol and sulphuric acid. The concept of kinetic acidity function has been generalized, its construction has been suggested, and the procedure has been applied to the solvolysis of 3-hydroxy-1,3-diphenyltriazenes. The kinetic acidity function found has been confronted with the H0 acidity function. The substituent effects have been evaluated with respect to mechanism of the acid catalyzed solvolysis.

The Acetic Anhydride-Sulphuric Reaction for General Paresis

1927 ◽  
Vol 73 (302) ◽  
pp. 419-421 ◽  
Author(s):  
A. G. Duncan
Keyword(s):  
Acetic Anhydride ◽  
Mental Disorder ◽  
Sulphuric Acid ◽  
Positive Reaction ◽  
Chemical Reaction ◽  
Spinal Fluid ◽  
General Paresis ◽  
Simple Chemical

While elaborating a test for cholesterol in the cerebro-spinal fluid, 0. H. Boltz (I) observed and investigated a reaction which occurred predominantly in cases of neuro-syphilis, and which he named the acetic anhydride-sulphuric test. To I c.c. of spinal fluid was added 03 c.c. of acetic anhydride, drop by drop, and after mixing the fluids by shaking, [email protected]. of concentrated sulphuric acid was added in drops, and the mixture shaken again. The development of a blue pink or lilac colour characterized a positive reaction. The test has been studied in this country, and it has been claimed that the reaction is positive in almost every case of general paresis, and negative in almost every other type of mental disorder, except certain cases of non-paretic neuro-syphilis. As this constitutes a surprising degree of specificity of an apparently simple chemical reaction for a single disease, I have carried out the reaction in association with the routine tests in a series of cerebro-spinal fluids with a view to ascertaining its value. One hundred and sixty fluids were examined—a comparatively small number on which to base conclusions, but the results will show that the claims previously advanced for the value of the test require considerable modification.

scholarly journals Study of the kinetics and equilibria of the oligomerization reactions of 2-methylglyceric acid

2013 ◽  
Vol 13 (6) ◽  
pp. 3097-3109 ◽  
Author(s):  
A. W. Birdsall ◽  
C. A. Zentner ◽  
M. J. Elrod
Keyword(s):  
Water Content ◽  
Chemical Species ◽  
Organic Aerosol ◽  
Bulk Phase ◽  
Oligomeric Form ◽  
Gaseous Precursor ◽  
Acid Catalyzed ◽  
Fischer Esterification ◽  
Phase Chemical ◽  
Atmospheric Chamber

Abstract. The presence of a variety of chemical species related to the gaseous precursor isoprene in ambient secondary organic aerosol (SOA) has stimulated investigations of the nature of SOA-phase chemical processing. Recent work has demonstrated that 2-methylglyceric acid (2-MG) is an important isoprene-derived ambient SOA component and atmospheric chamber experiments have suggested that 2-MG may exist in oligomeric form (as oligoesters) under conditions of low SOA water content. In order to better understand the thermodynamic and kinetic parameters of such oligomerization reactions, nuclear magnetic resonance techniques were used to study the bulk phase acid-catalyzed aqueous reactions (Fischer esterification) of 2-MG. While the present results indicate that 2-MG oligoesters are formed in the bulk phase with similar water content equilibrium dependences as observed in atmospheric chamber SOA experiments, the acid-catalyzed rate of the Fischer esterification mechanism may be too slow to rationalize the 2-MG oligoester production timescales observed in the atmospheric chamber experiments. Furthermore, it appears that unrealistically high ambient SOA acidities would also be required for significant 2-MG oligoester content to arise via Fischer esterification. Therefore, the present results suggest that other, more kinetically facile, esterification mechanisms may be necessary to rationalize the existence of 2-MG oligomers in atmospheric chamber-generated and ambient SOA.

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