In the present study, kinetics of synthesis of 2,2-di(prop-2-ynyl)-1H-indene-1,3(2H)-dione was successfully carried out by propargylation of indene-1,3-dione with propargyl bromide using aqueous potassium hydroxide and catalyzed by a newly synthesized phase-transfer catalyst viz., N-benzyl-N-ethyl-N-isopropylpropan-2-ammonium bromide, PTC under ultrasonic (40 kHz, 300 W) assisted organic solvent condition. The pseudo first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (40 kHz, 300 W) in a batch reactor, it shows that the overall reaction rate can be greatly enhanced with ultrasound irradiation than without ultrasound.
The kinetics of polymerization of acrylonitrile (AN) was carried out under heterogeneous condition using a new multi-site phase-transfer catalyst (MPTC), viz., N,N'-dihexyl-4,4'-bipyridinium dibromide in the presence of water soluble initiator, potassium peroxydisulphate (PDS) under chlorobenzene/water two phase system assisted by ultrasound irradiation at constant temperature 60+1°C under nitrogen atmosphere. The rate of polymerization increases with an increasing the concentrations of AN, MPTC and PDS. The order with respect to [AN], [MPTC], and [PDS] were found to be 1.01, 1.03 and 0.52, respectively. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations followed by a discussion on its significance.
In the present work, kinetics of synthesis of 1,3-bis(allyloxy)benzene was successfully carried out by O-allylation of resorcinol with allyl bromide using aqueous potassium hydroxide and catalyzed by a new multi-site phase-transfer catalyst viz., 1,3,5,7-tetrabenzylhexamethylenetetraammonium tetrachloride, MPTC under ultrasonic (40 kHz, 300 W) assisted organic solvent condition. The pseudo first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (40 kHz, 300 W) in a batch reactor, it shows that the overall reaction rate can be greatly enhanced to seven fold faster with ultrasound irradiation than without ultrasound. The present study provides a method to synthesize ethers by ultrasound assisted liquid-liquid phase-transfer catalysis condition.
The synthesis of di-p-tolylsulfane from the reaction of 4-bromo-1-methylbenzene (BMB) with sodium sulfide was carried out using a multi-site phase-transfer catalyst (MPTC) viz., 1,4-dihexyl-1,4-diazoniabicyclo[2.2.2]octanium dibromide and ultrasonic irradiation in a liquid-liquid reaction condition. The overall reaction rate is greatly enhanced when catalyzed by multi-site phase-transfer catalyst (MPTC) combined with sonication (40 kHz, 300 W) in a batch reactor than catalyzed by MPTC without sonication. Effects on the reaction due to various operating conditions, such as agitation speed, different ultrasound frequencies, different phase-transfer catalysts, different organic solvents, the amount of MPTC, temperature, amount of sodium sulfide, effect of sodium hydroxide, volume of n-hexane and the concentration of 4-bromo-1-methylbenzene. The reaction obeys a pseudo first-order rate law and a suitable mechanism was proposed based on the experimental observation.
In this work, the nitroarylation of imidazole catalyzed by a new novel dual-site phase-transfer catalyst was carried out in an alkaline solution/imidazole in chlorobenzene two-phase medium with ultrasonic irradiation (40 kHz, 300 W). This new synthesized phase-transfer catalyst, N(1),N(6)-diethyl-N(1),N(1),N(6),N(6)-tetraisopropylhexane-1,6-diaminium dichloride (MPTC), which possesses two-site activity, was obtained from the reaction of 1,6-dichlorohexane and N-ethyl-N-isopropylpropane-2-amine. The reaction of imidazole and alkali was carried out at the interface to generate sodium imidazole anion which can further react with MPTC form quaternary ammonium imidazole anion along with ultrasonic irradiation (40 kHz, 300 W). This ion-pair further react with 1-chloro-4-nitrobenzene which is present in the organic phase to produce 1-(4-nitropheny) imidazole. The reaction follows a pseudo first-order rate law. Kinetics of the reactions such as effect of the catalysts, ultrasonic effect, agitation speed, temperature, alkaline concentration, amount of 4-nitrochlorobenzene and the solvent effect on the reaction rate were investigated in detail. Peculiar phenomenon for the dependence of the reaction rate on the amount of MPTC and ultrasonication are explained satisfactorily.
The ultrasound assisted preparation of 1-(benzyloxy)-4-nitrobenzene from the reaction of 4-chloronitrobenzene (CNB) and benzyl alcohol was carried out successfully using potassium hydroxide and catalyzed by a new multi-site phase-transfer catalyst (MPTC) viz., 1,3,5-triethyl-1,3,5-trihexyl-1,3,5-triazinane-1,3,5-triium trichloride in a solid-liquid reaction condition (SL-MPTC). The advantage of using SL-MPTC is to avoid a serious hydration of potassium salt of benzyl alcohol in the reaction between 4-chloronitrobenzene (CNB) and benzyl alcohol. The reaction is greatly enhanced in the solid-liquid system, catalyzed by multi-site quaternary ammonium salt (MPTC) and ultrasound irradiation (40 kHz, 300 W) in a batch reactor, it shows that the overall reaction greatly enhanced with ultrasound irradiation than without ultrasound. The reaction mechanism is proposed and verified by examining the experimental evidence. A kinetic model is proposed in which a pseudo first-order rate law is sufficient to describe the results, such as the effects of agitation speed, ultrasound, different phase transfer catalysts and the effect of organic solvents, the amount of newly prepared MPTC, the effect of temperature, the amount of water, the concentration of 4-chloronitrobenzene (CNB) and potassium hydroxide concentrations. The apparent rate constant (kapp) were investigated in detail. Rational explanations to account for the phenomena on the results were made.
In the present research work, the solid-liquid reaction was successfully carried out in the new synthesized multisite phase-transfer catalyst, namely i.e., 1,3,5-tribenzyl-1,3,5-triethyl-1,3,5-triazinane-1,3,5-triium trichloride(MPTC), and sonication (40 kHz, 300 W) to produce the desired product namely 1-(4-nitropheny) pyrrole from pyrrole and 4-nitrochlorobenzene. The selectivity of N-arylation product was obtained under sonication and MPTC. The combination of ultrasound and MPTC resulted in better efficacy as compared to the individual operations. The apparent reaction rate is greatly enhanced and observed to obey the pseudo-first order kinetics. The k app value increases with increasing kinetic parameters that is the amount of [MPTC], [substrate], ultrasonication, stirring speed, temperature, etc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.