Pradyumankumar Joshi | Dharmsinh Desai University (original) (raw)
Papers by Pradyumankumar Joshi
Journal of Industrial and Engineering Chemistry, 2011
The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aq... more The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aqueous aromatic carboxylic acids (phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid) was carried out in the presence of UV radiation using air. The TiO2 catalyst, synthesized by sol–gel technique and calcined at 673K, resulted ca. 100% anatase phase with 23nm crystallite size and surface area of
Catalysis Communications, 2013
ABSTRACT The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated ... more ABSTRACT The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71–99%) to alkylated products with high selectivity in alkylation reactions.
Journal of Industrial and Engineering Chemistry, 2011
The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aq... more The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aqueous aromatic carboxylic acids (phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid) was carried out in the presence of UV radiation using air. The TiO2 catalyst, synthesized by sol–gel technique and calcined at 673K, resulted ca. 100% anatase phase with 23nm crystallite size and surface area of
Materials Science Forum, 2012
Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis bas... more Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis based on UV/titanium dioxide is one of the emerging technologies for degrading and totally mineralizing toxic and highly stable carboxylic ...
Bulletin of the Korean Chemical Society, 2012
An ecofriendly catalytic route for selective synthesis of N-substituted azacyclopentanes, nitroge... more An ecofriendly catalytic route for selective synthesis of N-substituted azacyclopentanes, nitrogen-containing heterocyclic intermediates for many bioactive compounds, was established by carrying out N-heterocyclization (di N-alkylation) of primary amines with 1,4-dichloro butane (as dialkylating agent) using catalytic amount of hydrotalcite as solid base catalyst. The hydrotalcite was found to be efficient solid base catalyst for di Nalkylation of different primary amines (aniline, benzyl amine, cyclohexyl amine and n-butyl amine) giving 82 to 96% conversion (at optimized reaction condition) of 1,4-dichloro butane and > 99% selectivity of respective N-substituted azacyclopentanes within 30 min. under solvent free condition. The reaction parameters significantly influence the conversion of 1,4-dichloro butane to N-substituted azacyclopentanes. The nature of substituent present on amino group affects the reactivity of amine substrates for di N-alkylation reaction with 1,4-dichloro butane. The 1,4-dichloro butane was found to be highly reactive alkylating agent for di Nalkylation of amines as compared to 1,4-dihydroxy butane. The reusability of the catalyst and its chemical stability in the reaction was demonstrated.
Catalysis Communications
The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean... more The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71–99%) to alkylated products with high selectivity in alkylation reactions.
Journal of Industrial and Engineering Chemistry
The cause of deactivation of Degussa P25 titanium dioxide (TiO2) during photocatalytic degradatio... more The cause of deactivation of Degussa P25 titanium dioxide (TiO2) during photocatalytic degradation of phthalic acid in aqueous medium was investigated. Various regeneration methods, such as washing with solvents, hydrogen peroxide (H2O2) and thermal treatment were attempted to find the best technique for regeneration of spent catalyst. The deactivation and regeneration of TiO2 was monitored using XRD, FTIR, CHNO analysis, zeta potential measurement and surface area analysis. The surface adsorption of phthalic acid and the reaction intermediates deactivates the catalyst. The regeneration by H2O2 treatment nearly restored the activity, whereas washing with solvents and thermal treatment showed poor regeneration.
THE FOURTH SAUDI ENGINEERING CONFERENCE, NOV. 1995 - VOLUME V COMPUTER AIDED DESIGN OF AN AZEOTRO... more THE FOURTH SAUDI ENGINEERING CONFERENCE, NOV. 1995 - VOLUME V COMPUTER AIDED DESIGN OF AN AZEOTROPIC DISTILLATION COLUMN MM Noor Wali and MD Bashir Department of Chemical & Material Engg. King AbduJaziz University, Jeddah, Saudi ...
Journal of Industrial and Engineering Chemistry
The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aq... more The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aqueous aromatic carboxylic acids (phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid) was carried out in the presence of UV radiation using air. The TiO2 catalyst, synthesized by sol–gel technique and calcined at 673K, resulted ca. 100% anatase phase with 23nm crystallite size and surface area of 37m2/g. This catalyst was found to be efficient for PCD of phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid in aqueous medium. However, the reactivity and degradation pathway of these carboxylic acids were observed to be greatly influenced by the substituent group present in the aromatic ring. The order of degradation of aromatic carboxylic acids was found to be phthalic acid>o-nitrobenzoic acid>o-chlorobenzoic acid>benzoic acid. The aromatic carboxylic acids having electron withdrawing groups such as –COOH, –NO2 and –Cl were comparatively ...
Materials Science Forum, 2012
Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis bas... more Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis based on UV/ titanium dioxide is one of the emerging technologies for degrading and totally mineralizing toxic and highly stable carboxylic acids from waste water has attracted great attention in last decade. The aliphatic and aromatic carboxylic acids are widely used as reactants or produced as main products or byproducts in various chemical process industries. These chemical process industries generates waste water containing significant amount of carboxylic acids, which need to be removed from waste water before disposal to natural water bodies due to the environmental restrictions and their hazardous effects on flora and fauna. This paper reviews photocatalytic degradation (PCD) process for various carboxylic acids in detail, including basic mechanism of titanium dioxide, effect of carboxylic acid structure and various reaction parameters like effect of initial concentration and kinetic...
Procedia Engineering, 2013
The mesoporous silica (MS) supported copper catalysts containing 2 wt. % copper in finely dispers... more The mesoporous silica (MS) supported copper catalysts containing 2 wt. % copper in finely dispersed form were synthesized and characterized. A comparative study on the effect of calcination temperature and reduction of the supported metal on catalytic property of supported copper species was carried out. The loading of copper on the supports provides good reducibility and catalytic activity for dehydrogenation of benzyl alcohol. The acidity and copper ions in mesoporous silica supported copper sample showed good activity in catalytic transformations of benzyl alcohol.
Industrial & Engineering Chemistry Research, 2014
ABSTRACT The silver-doped titanium dioxide (Ag–TiO2) photocatalysts with varied silver content ra... more ABSTRACT The silver-doped titanium dioxide (Ag–TiO2) photocatalysts with varied silver content ranging from 0.75 at % to 3.5 at % were synthesized by a single-step sol–gel method. The role of silver content on the properties of photocatalyst has been studied. The doping of 0.75 at % silver in TiO2 produced thermally stable TiO2 anatase phase with smallest particle size, uniform particles size and morphology, high surface area and low-energy excitation characteristics. The Ag–TiO2 sample with 0.75 at % silver possesses predominantly finely dispersed silver species (Ag2O and AgO) on the surface. The proportion of surface agglomerated silver metal (Ag0) increases as the silver content in the Ag–TiO2 sample increases. The silver oxide species were observed to be responsible for better physicochemical and catalytic properties. The TiO2 with 0.75 at % silver was found to be an efficient photocatalyst showing enhanced photocatalytic activity for aqueous medium photocatalytic degradation of phthalic acid in the presence of UV radiation and air.
Applied Clay Science, 2011
ABSTRACT Due to shorter half life of venlafaxine, it is a prime requirement to develop a formulat... more ABSTRACT Due to shorter half life of venlafaxine, it is a prime requirement to develop a formulation which could extend the release of venlafaxine in the human body and also eliminate daily multiple dosage of venlafaxine. Montmorillonite (MMT) was used as sustained release carrier for venlafaxine by preparing venlafaxine–MMT by ion exchange. Venlafaxine–MMT was coated with polyvinylpyrrolidone to delay the release of venlafaxine. In vitro releases of venlafaxine from the various formulations were carried out in simulated gastric and intestinal fluids in controlled environment. 50% of venlafaxine was released by intestinal fluid within 5 h, > 95% within 48 h. Venlafaxine–MMT coated with PVP further decreased the release of venlafaxine.Research Highlights►Formation of montmorillonite–venlafaxine hybrid. ►XRD, FTIR, TGA, and SEM confirmed the formation of hybrid. ►In vitro release of highly water soluble venlafaxine drug.
Journal of Industrial and Engineering Chemistry, 2013
ABSTRACT The Mg–Al hydrotalcite (HT) and Mg–Al mixed oxide supported copper catalysts containing ... more ABSTRACT The Mg–Al hydrotalcite (HT) and Mg–Al mixed oxide supported copper catalysts containing 3–3.5 wt.% copper in finely dispersed form were synthesized and characterized. The effect of support nature on physico-chemical and catalytic properties of supported copper species were studied. The loading of copper on the supports was observed to be influencing the surface acidic, basic and reducibility properties, and catalytic behavior in dehydrogenation of benzyl alcohol. The high basicity and intercalated copper ions in Mg–Al hydrotalcite supported copper sample showed multifunctional activity in catalytic transformations of alcohols (primary, secondary and aromatic alcohols).
Journal of Industrial and Engineering Chemistry, 2011
The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aq... more The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aqueous aromatic carboxylic acids (phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid) was carried out in the presence of UV radiation using air. The TiO2 catalyst, synthesized by sol–gel technique and calcined at 673K, resulted ca. 100% anatase phase with 23nm crystallite size and surface area of
Catalysis Communications, 2013
ABSTRACT The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated ... more ABSTRACT The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71–99%) to alkylated products with high selectivity in alkylation reactions.
Journal of Industrial and Engineering Chemistry, 2011
The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aq... more The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aqueous aromatic carboxylic acids (phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid) was carried out in the presence of UV radiation using air. The TiO2 catalyst, synthesized by sol–gel technique and calcined at 673K, resulted ca. 100% anatase phase with 23nm crystallite size and surface area of
Materials Science Forum, 2012
Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis bas... more Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis based on UV/titanium dioxide is one of the emerging technologies for degrading and totally mineralizing toxic and highly stable carboxylic ...
Bulletin of the Korean Chemical Society, 2012
An ecofriendly catalytic route for selective synthesis of N-substituted azacyclopentanes, nitroge... more An ecofriendly catalytic route for selective synthesis of N-substituted azacyclopentanes, nitrogen-containing heterocyclic intermediates for many bioactive compounds, was established by carrying out N-heterocyclization (di N-alkylation) of primary amines with 1,4-dichloro butane (as dialkylating agent) using catalytic amount of hydrotalcite as solid base catalyst. The hydrotalcite was found to be efficient solid base catalyst for di Nalkylation of different primary amines (aniline, benzyl amine, cyclohexyl amine and n-butyl amine) giving 82 to 96% conversion (at optimized reaction condition) of 1,4-dichloro butane and > 99% selectivity of respective N-substituted azacyclopentanes within 30 min. under solvent free condition. The reaction parameters significantly influence the conversion of 1,4-dichloro butane to N-substituted azacyclopentanes. The nature of substituent present on amino group affects the reactivity of amine substrates for di N-alkylation reaction with 1,4-dichloro butane. The 1,4-dichloro butane was found to be highly reactive alkylating agent for di Nalkylation of amines as compared to 1,4-dihydroxy butane. The reusability of the catalyst and its chemical stability in the reaction was demonstrated.
Catalysis Communications
The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean... more The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71–99%) to alkylated products with high selectivity in alkylation reactions.
Journal of Industrial and Engineering Chemistry
The cause of deactivation of Degussa P25 titanium dioxide (TiO2) during photocatalytic degradatio... more The cause of deactivation of Degussa P25 titanium dioxide (TiO2) during photocatalytic degradation of phthalic acid in aqueous medium was investigated. Various regeneration methods, such as washing with solvents, hydrogen peroxide (H2O2) and thermal treatment were attempted to find the best technique for regeneration of spent catalyst. The deactivation and regeneration of TiO2 was monitored using XRD, FTIR, CHNO analysis, zeta potential measurement and surface area analysis. The surface adsorption of phthalic acid and the reaction intermediates deactivates the catalyst. The regeneration by H2O2 treatment nearly restored the activity, whereas washing with solvents and thermal treatment showed poor regeneration.
THE FOURTH SAUDI ENGINEERING CONFERENCE, NOV. 1995 - VOLUME V COMPUTER AIDED DESIGN OF AN AZEOTRO... more THE FOURTH SAUDI ENGINEERING CONFERENCE, NOV. 1995 - VOLUME V COMPUTER AIDED DESIGN OF AN AZEOTROPIC DISTILLATION COLUMN MM Noor Wali and MD Bashir Department of Chemical & Material Engg. King AbduJaziz University, Jeddah, Saudi ...
Journal of Industrial and Engineering Chemistry
The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aq... more The comparative study on titanium dioxide (TiO2) catalyzed photocatalytic degradation (PCD) of aqueous aromatic carboxylic acids (phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid) was carried out in the presence of UV radiation using air. The TiO2 catalyst, synthesized by sol–gel technique and calcined at 673K, resulted ca. 100% anatase phase with 23nm crystallite size and surface area of 37m2/g. This catalyst was found to be efficient for PCD of phthalic acid, o-nitrobenzoic acid, o-chlorobenzoic acid and benzoic acid in aqueous medium. However, the reactivity and degradation pathway of these carboxylic acids were observed to be greatly influenced by the substituent group present in the aromatic ring. The order of degradation of aromatic carboxylic acids was found to be phthalic acid>o-nitrobenzoic acid>o-chlorobenzoic acid>benzoic acid. The aromatic carboxylic acids having electron withdrawing groups such as –COOH, –NO2 and –Cl were comparatively ...
Materials Science Forum, 2012
Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis bas... more Among the new oxidation methods in advanced oxidation processes, heterogeneous photocatalysis based on UV/ titanium dioxide is one of the emerging technologies for degrading and totally mineralizing toxic and highly stable carboxylic acids from waste water has attracted great attention in last decade. The aliphatic and aromatic carboxylic acids are widely used as reactants or produced as main products or byproducts in various chemical process industries. These chemical process industries generates waste water containing significant amount of carboxylic acids, which need to be removed from waste water before disposal to natural water bodies due to the environmental restrictions and their hazardous effects on flora and fauna. This paper reviews photocatalytic degradation (PCD) process for various carboxylic acids in detail, including basic mechanism of titanium dioxide, effect of carboxylic acid structure and various reaction parameters like effect of initial concentration and kinetic...
Procedia Engineering, 2013
The mesoporous silica (MS) supported copper catalysts containing 2 wt. % copper in finely dispers... more The mesoporous silica (MS) supported copper catalysts containing 2 wt. % copper in finely dispersed form were synthesized and characterized. A comparative study on the effect of calcination temperature and reduction of the supported metal on catalytic property of supported copper species was carried out. The loading of copper on the supports provides good reducibility and catalytic activity for dehydrogenation of benzyl alcohol. The acidity and copper ions in mesoporous silica supported copper sample showed good activity in catalytic transformations of benzyl alcohol.
Industrial & Engineering Chemistry Research, 2014
ABSTRACT The silver-doped titanium dioxide (Ag–TiO2) photocatalysts with varied silver content ra... more ABSTRACT The silver-doped titanium dioxide (Ag–TiO2) photocatalysts with varied silver content ranging from 0.75 at % to 3.5 at % were synthesized by a single-step sol–gel method. The role of silver content on the properties of photocatalyst has been studied. The doping of 0.75 at % silver in TiO2 produced thermally stable TiO2 anatase phase with smallest particle size, uniform particles size and morphology, high surface area and low-energy excitation characteristics. The Ag–TiO2 sample with 0.75 at % silver possesses predominantly finely dispersed silver species (Ag2O and AgO) on the surface. The proportion of surface agglomerated silver metal (Ag0) increases as the silver content in the Ag–TiO2 sample increases. The silver oxide species were observed to be responsible for better physicochemical and catalytic properties. The TiO2 with 0.75 at % silver was found to be an efficient photocatalyst showing enhanced photocatalytic activity for aqueous medium photocatalytic degradation of phthalic acid in the presence of UV radiation and air.
Applied Clay Science, 2011
ABSTRACT Due to shorter half life of venlafaxine, it is a prime requirement to develop a formulat... more ABSTRACT Due to shorter half life of venlafaxine, it is a prime requirement to develop a formulation which could extend the release of venlafaxine in the human body and also eliminate daily multiple dosage of venlafaxine. Montmorillonite (MMT) was used as sustained release carrier for venlafaxine by preparing venlafaxine–MMT by ion exchange. Venlafaxine–MMT was coated with polyvinylpyrrolidone to delay the release of venlafaxine. In vitro releases of venlafaxine from the various formulations were carried out in simulated gastric and intestinal fluids in controlled environment. 50% of venlafaxine was released by intestinal fluid within 5 h, > 95% within 48 h. Venlafaxine–MMT coated with PVP further decreased the release of venlafaxine.Research Highlights►Formation of montmorillonite–venlafaxine hybrid. ►XRD, FTIR, TGA, and SEM confirmed the formation of hybrid. ►In vitro release of highly water soluble venlafaxine drug.
Journal of Industrial and Engineering Chemistry, 2013
ABSTRACT The Mg–Al hydrotalcite (HT) and Mg–Al mixed oxide supported copper catalysts containing ... more ABSTRACT The Mg–Al hydrotalcite (HT) and Mg–Al mixed oxide supported copper catalysts containing 3–3.5 wt.% copper in finely dispersed form were synthesized and characterized. The effect of support nature on physico-chemical and catalytic properties of supported copper species were studied. The loading of copper on the supports was observed to be influencing the surface acidic, basic and reducibility properties, and catalytic behavior in dehydrogenation of benzyl alcohol. The high basicity and intercalated copper ions in Mg–Al hydrotalcite supported copper sample showed multifunctional activity in catalytic transformations of alcohols (primary, secondary and aromatic alcohols).