P. S. T. Sai

Bio: P. S. T. Sai is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Catalysis & Pressure drop. The author has an hindex of 2, co-authored 5 publications receiving 13 citations.

Kinetics of Esterification of Acetic Acid and Ethanol with a Homogeneous Acid Catalyst

Abstract: In the present work, esterification reaction between acetic acid and ethanol was conducted in an isothermal batch reactor in the presence of a homogeneous acid catalyst sulphuric acid. The progress of the reaction was monitored by following the concentration of water measured using Karl Fischer titrator. The variables include the mole ratio of reactants, reaction temperature and catalyst concentration. The mole ratio of alcohol to acid was varied from 1 to 5, the reaction temperature between 20°C and 60°C and the catalyst concentration was varied from 1 to 10 weight per cent. The operating conditions for better yield of ester were identified. The experimental data were analysed by an integral method of analysis to obtain the order of the reaction. The reaction rate constants, frequency factor and activation energies have been determined. The kinetic model derived from the mechanism fits the experimental data satisfactorily. The activity coefficients of the system calculated using UNIFAC and modifi...

Effect of gas bypassing and operating parameters on coal gasification in internally circulating fluidised bed

Abstract: In internally circulating fluidised bed, there occurs gas bypassing from draught to annulus region and vice versa. The effect of gas bypassing on product gas composition in both annulus and...

Continuous segregation of binary mixture of solids in liquid fluidised beds: influence of feed entry location

Abstract: The effect of feed entry location on segregation of the binary mixture of solids in a continuous liquid fluidised bed has been investigated in the present study. Three different feed entry locations were selected and examined in a 72 mm ID and 3 m height continuous liquid fluidised bed. The binary feed mixture consists of different sized particles of same density with different compositions. The significant observations noticed at various feed entry locations on fluidisation behaviour are discussed. While feed entry location had a significant influence on purity and recovery of top and bottom products, it had no appreciable influence on pressure drop profile, entrainment and discharge rates of solids. The optimum liquid velocity and optimum purity/recovery were identified for every feed entry location for maximum separation of both the particles.

Continuous segregation of homogeneous binary mixture of solids by a liquid fluidised bed classifier

Abstract: Continuous segregation of homogeneous binary mixture of solids was experimentally investigated in a liquid fluidised bed with water as the fluidising medium. Experiments were conducted to study the...

Enhancement of Esterification Reaction between Ethanol and Sulphuric Acid Using Ionic Liquids

Abstract: Experiments were conducted in a batch reactor under isothermal conditions to study the enhancement of the esterification reaction between ethanol and sulphuric acid with ionic liquid as catalyst. The three catalysts used for the study were 1-butyl 3-methylimidazolium octyl sulphate, 1-ethyl 3-methylimidazolium octyl sulphate and 1-butyl 3-methylimidazolium methyl sulphate. The effect of reaction temperature, catalyst concentration and type of catalyst on conversion of the reactant was studied to obtain the kinetics of the reaction. The conversion levels increased with increasing catalyst concentration and decreased with increasing reaction temperature in the temperature range investigated. The rate data fitted first-order kinetics at high concentrations of the reactant and zero-order kinetics at low concentrations of the reactant, thus exhibiting shifting order-type kinetics. The proposed reaction mechanism suggested the possibility of splitting of the ionic liquid before participating in the reac...

Synthesis and Characterization of Zirconia Supported Silicotungstic Acid for Ethyl Levulinate Production

Abstract: A Keggin silicotungstic acid (HPS) catalyst was heterogenized by loading (10–40 wt %) over zirconia support, and the resulting catalysts were named ESZN-1 (10 wt %), ESZN-2 (20 wt %), ESZN-3 (30 wt...

“Pushing and pulling” the equilibrium through bubble mediated reactive separation for ethyl acetate production

Abstract: Esterification, a reaction extensively used in chemical processing, is limited by the establishment of kinetic equilibrium, i.e. marginally exer/endergonic. The reaction is generally slow with low yield making downstream separation cost intensive. A new heterogeneous contacting method for the synthesis of ethyl acetate through fine bubbles tests the hypothesis that reactive distillation can “pull” the reaction nearer to completion, reducing the downstream separation requirements. It achieves a high yield of ethyl acetate, 79.9% in 35 min, as compared with 64% conversion in 350 min using a conventional method. The kinetics of esterification reaction under bubbly flow conditions are studied – entirely different from the conventional bulk model. The alcohol is fed as vapor within the bubbles which means alcohol is always in deficit, providing an opportunity to convert an equilibrium limited reaction to nearly irreversible one. As the bubbles flow upwards, the reaction proceeds at the “skin” of the bubble. If the esterification reaction occurs at or near the microbubble interface, ethanol is in large excess in the bubble phase, as acetic acid is well below its boiling point in the liquid phase. By Le Chatelier's principle, the local excess ethanol will push the equilibrium towards completion. Similarly, removal of water and ethyl acetate via the “dry” bubble pulls the equilibrium towards completion.

Mechanism of tetralin conversion on zeolites for the production of benzene derivatives

Abstract: Ring-opening of tetralin, which is produced by partial dehydrogenation of naphthalene, was catalyzed by various zeolites. Influences of acidity and textural properties of the zeolites on the activity and selectivity were studied in the reactions of not only tetralin but also butylbenzene and indane as the intermediate models in tetralin conversion. The *BEA zeolite exhibited higher conversion and selectivity to benzene and its derivatives (butylbenzene, toluene, xylenes and ethylbenzene) than the other framework type zeolites. The simultaneous cracking of butylbenzene principally produced benzene. The reaction rate in the ring-opening of tetralin was considerably high on strong Bronsted acid sites in the 12-ring of the *BEA zeolite. The amount of Bronsted acid sites on the *BEA zeolite increased the tetralin conversion but did not affect the selectivity to the products. In tetralin conversion, MOR and FAU zeolites formed more methylindane and naphthalene as by-products, respectively. Methylindane was produced on weak Bronsted acid sites through ring-contraction of tetralin, and naphthalene was formed on Lewis acid sites through dehydrogenation. The influences of the reaction conditions on the catalytic activity in tetralin conversion were also investigated. The contact time increased the conversion, but hardly affected the selectivities to the products. The total pressure also improved the catalytic activity. The pressurized hydrogen decreased the selectivity for methylindane, while it increased for benzene and its derivatives. At 573 K, the selectivities to benzene and its derivatives were high, but the reaction temperature increased the selectivity to the by-products.

Kinetic Study of Homogeneous Catalyzed Esterification of a Series of Aliphatic Acids with Different Alcohols

Abstract: The kinetic study of esterification of series of aliphatic carboxylic acids (C1–C5) with various alcohols (n-propanol, isopropanol, and n-butanol) have been conducted using sulfuric acid as a catal...