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Donald G M Anderson - One of the best experts on this subject based on the ideXlab platform.
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mechanism and temperature dependent kinetics of the dehydration of Tert Butyl Alcohol in hot compressed liquid water
Industrial & Engineering Chemistry Research, 1997Co-Authors: Michael Jerry Antal, Donald G M AndersonAbstract:In the presence of acid or base, or under neutral conditions, isoButylene is the only observed product of the reactions of Tert-Butyl Alcohol in compressed liquid water at 225, 250, and 320 C. On the basis of a kinetic analysis of limited results at 250 C, an earlier paper concluded that Tert-Butyl Alcohol dissociates as an Arrhenius acid at 250 C and thereby catalyzes its own dehydration to isoButylene. Kinetic analyses of the data sets contained in this paper do not corroborate the alleged ability of Tert-Butyl Alcohol to protonate water. Instead, the authors find that hydronium ions formed by the ordinary dissociation of water are the primary catalytic agents for the dehydration reaction. In agreement with the earlier work, all three data sets are consistent with a heterolytic reaction mechanism involving protonated Alcohol, carbocation, di-Tert-Butyl ether, and protonated ether as intermediates. The kinetics still suggest that Tert-Butyl Alcohol weakly dissociated as a Bronsted acid at these conditions. Values of K{sub w} determined by the kinetic model enjoy good agreement with electrochemical values available in the literature. Values of the other parameters (rate constants) which compose the kinetic model are evaluated with less precision, and a novel method is proposedmore » to estimate the uncertainty associated with each parameter.« less
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mechanism and temperature dependent kinetics of the dehydration of Tert Butyl Alcohol in hot compressed liquid water
Industrial & Engineering Chemistry Research, 1997Co-Authors: Michael Jerry Antal, Donald G M AndersonAbstract:In the presence of acid or base, or under neutral conditions, isoButylene is the only observed product of the reactions of Tert-Butyl Alcohol in compressed liquid water at 225, 250, and 320 °C. On ...
Congjie Gao - One of the best experts on this subject based on the ideXlab platform.
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freeze casting of novel porous silicate cement supports using Tert Butyl Alcohol water binary crystals as template microstructure strength and permeability
Journal of Membrane Science, 2017Co-Authors: Senjie Dong, Wenzhuo Zhu, Xueli Gao, Zhen Wang, Leyi Wang, Congjie GaoAbstract:Abstract Freeze casting liquid dispersions of solid particles is an effective method for preparing porous composites, thus creating strong and lightweight materials with “designed” microstructures for various applications. This work illuminates that Tert-Butyl Alcohol (TBA)/water (H2O) mutually miscible system can be used as template to prepare aligned porous silicate cement supports with unique pore structures via directional freezing. The resulting pore morphology of porous cement substrates changes from prismatic to needle-like, dendritic, coralline, graininess and lamellar structure with the increasing of TBA-H2O ratio in cement slurry. Pore size distributions (macropores and mesopores) demonstrate the hierarchical pore structure of porous cement. The BET surface area (SBET) of porous cement support increases with the decreasing TBA content in cement slurry, until the pore forming agent was pure water. Porous cement that are fabricated from mixed slurries with relatively high TBA-H2O ratio show better mechanical strength. Porous cement support prepared from cement slurry with 90 wt% TBA exhibits the best permeation performance due to its well-distributed and oriented pore structure. These findings demonstrate how an aligned and hierarchical porous inorganic support with desirable properties can be prepared, under mild conditions, with the combination of advanced casting technique and most ancient construction material on earth.
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Preparation of tubular hierarchically porous silicate cement compacts via a Tert-Butyl Alcohol (TBA)-based freeze casting method
Chemical Engineering Journal, 2016Co-Authors: Senjie Dong, Wenzhuo Zhu, Xueli Gao, Zhen Wang, Leyi Wang, Xinyan Wang, Congjie GaoAbstract:Tubular porous silicate cement compacts with hierarchical porosity were successfully fabricated via a Tert-Butyl Alcohol (TBA)-based freeze-casting technique in one single step. These samples were characterized by unidirectional aligned pore channels and completely open porosity. Various experimental parameters affecting the macropore size, mesopore size, porosity, and compression strength were investigated, including the initial solids loading, freezing temperature and curing period. Both the research findings of microstructure observations and property tests show that the pore size decreased significantly with decreasing freezing temperature and increasing solids loading. The porosity increased significantly with decreasing solids loading, while the compressive strength decreased remarkably. In addition to their tunable physical characteristics, these brand-new inorganic porous materials with oriented aligned pore channels and dense layer surface showed high permeation performance and desirable separation ability. These results endow the silicate cement, a kind of low-cost and high-performance architecture material, with great potential as a novel ordered porous inorganic material for numerous applications, especially in separation process.
Michael Jerry Antal - One of the best experts on this subject based on the ideXlab platform.
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mechanism and temperature dependent kinetics of the dehydration of Tert Butyl Alcohol in hot compressed liquid water
Industrial & Engineering Chemistry Research, 1997Co-Authors: Michael Jerry Antal, Donald G M AndersonAbstract:In the presence of acid or base, or under neutral conditions, isoButylene is the only observed product of the reactions of Tert-Butyl Alcohol in compressed liquid water at 225, 250, and 320 C. On the basis of a kinetic analysis of limited results at 250 C, an earlier paper concluded that Tert-Butyl Alcohol dissociates as an Arrhenius acid at 250 C and thereby catalyzes its own dehydration to isoButylene. Kinetic analyses of the data sets contained in this paper do not corroborate the alleged ability of Tert-Butyl Alcohol to protonate water. Instead, the authors find that hydronium ions formed by the ordinary dissociation of water are the primary catalytic agents for the dehydration reaction. In agreement with the earlier work, all three data sets are consistent with a heterolytic reaction mechanism involving protonated Alcohol, carbocation, di-Tert-Butyl ether, and protonated ether as intermediates. The kinetics still suggest that Tert-Butyl Alcohol weakly dissociated as a Bronsted acid at these conditions. Values of K{sub w} determined by the kinetic model enjoy good agreement with electrochemical values available in the literature. Values of the other parameters (rate constants) which compose the kinetic model are evaluated with less precision, and a novel method is proposedmore » to estimate the uncertainty associated with each parameter.« less
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mechanism and temperature dependent kinetics of the dehydration of Tert Butyl Alcohol in hot compressed liquid water
Industrial & Engineering Chemistry Research, 1997Co-Authors: Michael Jerry Antal, Donald G M AndersonAbstract:In the presence of acid or base, or under neutral conditions, isoButylene is the only observed product of the reactions of Tert-Butyl Alcohol in compressed liquid water at 225, 250, and 320 °C. On ...
Sreedevi Upadhyayula - One of the best experts on this subject based on the ideXlab platform.
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highly efficient alkylation of phenol with Tert Butyl Alcohol using environmentally benign bronsted acidic ionic liquids
Applied Catalysis A-general, 2015Co-Authors: Tanmoy Patra, Salahuddin Ahamad, Sreedevi UpadhyayulaAbstract:Abstract A series of SO 3 -H functionalized environmentally benign Bronsted acidic ionic liquids were prepared using triethylamine, 1-methyl imidazole, pyridine, diethanolamine, 1,4-butane sultone and methane sulfonic acid as the starting materials. These synthesized ionic liquid catalysts were characterized using spectroscopic tools like 1 H NMR, 13 C NMR. The catalytic activity of the synthesized ionic liquids was investigated in Tert -Butylation of phenol with Tert -Butyl Alcohol. The effect of kinetic parameters like reaction time, reaction temperature, reactant mole ratio, reactant to catalyst mole ratio, on the conversion of phenol and selectivity to 2- Tert -Butyl-phenol and 2,4-di- Tert -Butyl-phenol were investigated. Phenol conversion upto 94.2% was achieved at temperature as low as 80 °C and low Alcohol to phenol molar ratio of 2:1, ionic liquid to phenol ratio of 1:1 and reaction time of 2 h. The catalyst was found to retain its activity even after 8 recycles and was completely recoverable. The plausible reaction mechanism was formulated based on product distribution. The kinetic data was found to agree well with classical phenomenological models and the kinetic parameters were estimated. The experimental results were further validated by Density Functional Theory (DFT) optimizations of the ionic liquid structures performed at the B3LYP/6-311G** level using Gaussian 09 package.
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Kinetics of phenol alkylation with Tert-Butyl Alcohol using sulfonic acid functional ionic liquid catalysts
Chemical Engineering Journal, 2011Co-Authors: Pandian Elavarasan, Kishore Kondamudi, Sreedevi UpadhyayulaAbstract:Abstract N-methyl imidazole, pyridine and triethylamine based Bronsted acidic ionic liquids with sulfonic acid (–SO3H) functionality were obtained using 1,4-butane sultone. They were tested in a batch reactor for catalytic activity in the Tert-Butylation of phenol with Tert-Butyl Alcohol (TBA). The reaction time, reaction temperature and reactant mole ratio were optimized. Among the three ionic liquids, triethylammonium based sulfonic acid functionalized ionic liquid was found to be the most promising and gave the highest phenol conversion. A maximum phenol conversion of 86% with 57.6% selectivity to 4-Tert-Butylphenol (4-TBP) was achieved at a temperature of 70 °C at a low ionic liquid to phenol ratio. The catalyst retained its activity even after 5 recycles. A kinetic model was developed for the reaction mechanism based on the product distribution and the kinetic parameters were estimated. The activation energy for ionic liquid catalyzed alkylation of phenol was found to be 11.13 kcal/mol in the temperature range of 50–90 °C. Negative activation energy was observed for 2-Tert-Butylphenol (2-TBP) to 2,4-di-Tert-Butylphenol (2,4-DTBP) and the extended Arrhenius equation was used to interpret this trend.
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statistical optimization of process variables in batch alkylation of p cresol with Tert Butyl Alcohol using ionic liquid catalyst by response surface methodology
Chemical Engineering Journal, 2009Co-Authors: Pandian Elavarasan, Kishore Kondamudi, Sreedevi UpadhyayulaAbstract:Abstract Alkylation of p-cresol with Tert-Butyl Alcohol was studied using ionic liquid catalyst prepared from N-(1,4-sulfonic acid) Butyl triethylammonium hydrogen sulfate. An experimental design using response surface methodology (RSM) is used to optimize the process parameters in this batch alkylation to minimize rigorous experimental procedures and conserve the catalyst. The parameters, namely, temperature, reactant mole ratio, catalyst (IL) to p-cresol mole ratio and time of reaction on the conversion of p-cresol and yield of 2-Tert-Butyl-p-cresol (TBC) were optimized using Box–Behnken design. Low temperature, low p-cresol to Alcohol ratio and low catalyst (IL) to p-cresol ratio in a batch reactor were found to maximize conversion of p-cresol and yield of TBC.
B Satyavathi - One of the best experts on this subject based on the ideXlab platform.
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design and operation of extractive distillation systems using different class of entrainers for the production of fuel grade Tert Butyl Alcohol a techno economic assessment
Energy, 2018Co-Authors: Vineet Aniya, B Satyavathi, Ashish SinghAbstract:Abstract The 21st century beholds interest in biofuels, leading to a key challenge being the production of fuel grade ‘Tert Butyl Alcohol’ (TBA) with reduced economics. As a consequent step in the investigation with a different class of entrainers for TBA dehydration (Aniya et al. 2015, 2016) through extractive distillation (ED), the present study explores the utilization of ionic liquid [emim][Cl] and inorganic salt [MgCl2] as a potent entrainer. A comprehensive approach is proposed with phase-equilibrium measurements, thermodynamic modeling, design and process optimization using Aspen Plus. A techno-economic assessment of all the investigated processes (conventional solvents: CSED, solvent + salt: SEED, designer solvents or ionic liquids: DEED and ionic liquid + salt: DSEED) concluded SEED process to be the most promising with 6%, 18% and 37% savings in TAC and 9%, 23% and 41% savings in SEC as compared to the DSEED, DEED and CSED processes respectively. Further, retrofits (heat integration and thermally coupled schemes) demonstrated 13% and 6% reduction in specific energy consumption respectively thus improving the energy efficiency of ED systems. Heat integration brought in 12% savings in TAC over SEED process. However, thermally coupled schemes resulted in marginal benefit (2% savings) in terms of TAC over SEED process.
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comprehensive approach toward dehydration of Tert Butyl Alcohol by extractive distillation entrainer selection thermodynamic modeling and process optimization
Industrial & Engineering Chemistry Research, 2016Co-Authors: Vineet Aniya, B SatyavathiAbstract:Recently, Tert-Butyl Alcohol (TBA) has emerged as a commercially competent reagent for biofuel production, but forms a minimum boiling azeotrope with water which restricts its applicability. This paper presents a comprehensive methodology for the dehydration of TBA by extractive distillation (ED). In entrainer selection, glycolic and ionic liquids were investigated followed by VLE measurements and thermodynamic modeling. On the basis of evaluated results, pseudobinary, isovolatility and equivolatility curves have been explored to rank accurately the selected entrainers. Triethylene glycol (TEG) and 1-ethyl-3-methylimidazolium chloride [emim][Cl] emerged as the most appropriate entrainer. Finally, the process design and optimization was carried out with the minimization of total annualized cost (TAC) as the objective function. The process economics demonstrated a notable reduction of 13.9% in the TAC for [emim][Cl] as compared to TEG as an entrainer for obtaining anhydrous TBA, thereby justifying the use o...
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isobaric phase equilibrium of Tert Butyl Alcohol glycerol at local and subatmospheric pressures volumetric properties and molar refractivity from 303 15 to 333 15 k of Tert Butyl Alcohol glycerol Tert Butyl Alcohol water and water glycerol binary systems
Journal of Chemical & Engineering Data, 2016Co-Authors: Vineet Aniya, Ashish Kumar Singh, B SatyavathiAbstract:Isobaric vapor–liquid equilibrium for the binary system of Tert-Butyl Alcohol (TBA) + glycerol were obtained at local atmospheric pressure of 95.9 kPa and subatmospheric pressures of 66.6 and 79.9 kPa over the entire composition range using a modified Othmer-type ebulliometer. Wilson and NRTL models were used for correlating the experimental data. The results suggest that the NRTL model represented the experimental data better with lower RMSD and AAD values. Furthermore, at local atmospheric pressure of 95.9 kPa, the densities and refractive indices for the three binary systems TBA + glycerol, TBA + water, and water + glycerol involved in the dehydration of TBA by extractive distillation were measured over the entire composition range from 303.15 to 333.15 K. The volumetric properties in terms of excess molar volume, partial molar volume, and isobaric thermal expansivities as well as molar refractivity were evaluated and analyzed for the three different binary systems. A Redlich–Kister polynomial was used...