Microwave heating for the rapid determination of thermodynamic functions of chemical reactions

Bacci, Mauro; Bini, M.; Checcucci, A; Ignesti, A.; Millanta, L.M.; Rubino, N.; Vanni, R.

doi:10.1039/f19817701503

Cited by 10 publications

(11 citation statements)

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“…In previous studies on the application of microwaves in heterogeneous catalysis, all the reactions studied, including the decomposition of H 2 S, reduction of SO 2 with CH 4 , and the CO 2 reforming of CH 4 , have been endothermic so that the proposed hot-spots could result not only in an acceleration in reaction rates but also an apparent shift in equilibrium, giving a higher reactant conversion than that expected at the observed temperature. In this strongly exothermic HDS reaction, according to the arguments developed above, the equilibrium conversion will decrease as the temperature is increased.…”

Section: à1 ð10þmentioning

confidence: 99%

“…Microwave radiation as a remote heating source was developed subsequently and is well established in society in domestic microwave ovens and industrial systems. The application of microwave dielectric heating to chemical systems attracted great interest following the publication of two important papers in 1986 [2,3], although initial reports indicating the potential of the technique had been published in 1981 for chemical synthesis [4] and in 1967 for polymer applications [5]. Over the last decade, in particular, the development of microwave-assisted chemistry has witnessed an explosive growth, as detailed below.…”

Section: Introductionmentioning

confidence: 99%

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Applications of microwave dielectric heating in environment-related heterogeneous gas-phase catalytic systems

Zhang

Hayward

2006

Inorganica Chimica Acta

167

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The application of microwave dielectric heating in a range of environment-related heterogeneous catalytic reaction systems has been reviewed. The reactions investigated include the decomposition of hydrogen sulfide, the reduction of sulfur dioxide with methane, the reformation of methane by carbon dioxide, the hydrodesulfurization of thiophene, and the oxidative coupling of methane. The interaction of microwave irradiation with heterogeneous catalytic systems and its consequence for the microwave heating behaviour of catalysts have been examined. The effect/mechanism of microwave dielectric heating on heterogeneous catalytic reaction systems has also been discussed.

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Section: à1 ð10þmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Applications of microwave dielectric heating in environment-related heterogeneous gas-phase catalytic systems

Zhang

Hayward

2006

Inorganica Chimica Acta

167

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“…Although several chemical applications of microwave heating have been reported (1)(2)(3)(4)(5), it is only recently that microwave ovens have been used in organic synthesis (6,7). In a preliminary communication (6) we described the use of microwave ovens for synthesizing esters from carboxylic acids, carboxylic acids from alkyl benzenes and amides, and ethers from alkyl halides.…”

Section: Introductionmentioning

confidence: 99%

The rapid synthesis of organic compounds in microwave ovens

Gedye¹,

Smith²,

Westaway³

1988

Can. J. Chem.

261

110

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This work demonstrates that organic compounds can be synthesized up to 1240 times faster in sealed Teflon vessels in a microwave oven than by conventional (reflux) techniques. It is shown that all polar molecules absorb microwave energy rapidly and that the rate of energy absorption varies with the dielectric constant. The rates of reaction of polar molecules in nonpolar solvents are not increased appreciably by the microwave method. Also, the homogeneity of the reaction does not affect the rate enhancement. The rate enhancement arises predominantly because the oven superheats the solvent rapidly. Finally, pressure (temperature) measurements have shown that the maximum rate enhancement is achieved when the proper power level and volume of solvent are used. It appears that rate enhancements of approximately 200 are possible for many reactions if the reaction conditions are optimized.RICHARD N. GEDYE, FRANK E. SMITH et KENNETH CHARLES WESTAWAY. Can. J. Chem. 66, 17 (1988).Dans ce travail, on demontre que les composCs organiques peuvent &tre synthCtisCs 1240 fois plus rapidement dans des rkcipients de TCflon scelles, dans des fours a micro-ondes, que par les techniques conventionnelles de reflux. On dCmontre que toutes les molCcules polaires absorbent rapidement 1'Cnergie des micro-ondes et que les vitesses d'absorption de 1'Cnergie varient avec la constante diklectrique. La mCthode des micro-ondes ne provoque pas en une augmentation substantielle des vitesses des rCaetions impliquant des molCcules polaires dans des solvants qui ne sont pas polaires. De plus, I'homogCnCitC du milieu reactionnel n'influence pas le taux d'augmentation des vitesses des rkactions. L'augmentation des vitesses des reactions provient principalement du fait que le four provoque une surchauffe rapide du solvant. Enfin, des mesures de pression (tempkrature) ont permis de dtmontrer que le taux maximal d'augmentation des vitesses de rCaction est atteint lorsqu'on utilise un niveau de puissance et un volume de solvant appropriCs. I1 semble que l'on puisse atteindre des taux d'augmentation des vitesses de rCactions d'environ 200 si les conditions des rCactions sont optimisCes.[Traduit par la revue] Introduction Although several chemical applications of microwave heating have been reported (1-5), it is only recently that microwave ovens have been used in organic synthesis (6, 7). In a preliminary communication (6) we described the use of microwave ovens for synthesizing esters from carboxylic acids, carboxylic acids from alkyl benzenes and amides, and ethers from alkyl halides. In fact, these organic reactions occurred up to 1240 times more rapidIy in sealed Teflon containers in the microwave oven than by classical reflux methods. Since then, Giguere et al. (7) reported dramatic reductions in reaction time in microwave syntheses using the Diels-Alder, Claisen, and ene reactions.The present paper extends the scope of this new synthetic method and reports our investigations of several of the factors that affect the rate enhancements found in organi...

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“…Microwave-induced polymerization [7], moisture analysis [8], wet ashing procedures of biological and geological materials [9][10][11], heating of ore sample and acid mixtures in sealed vessel to reduce the time of dissolution [12], catalytic hydrogenation of alkenes [13], rapid determination of various thermodynamic functions of a reaction [14], etc., were reported between the late 1960s and the early 1980s. Microwave-induced polymerization [7], moisture analysis [8], wet ashing procedures of biological and geological materials [9][10][11], heating of ore sample and acid mixtures in sealed vessel to reduce the time of dissolution [12], catalytic hydrogenation of alkenes [13], rapid determination of various thermodynamic functions of a reaction [14], etc., were reported between the late 1960s and the early 1980s.…”

Section: Seven-membered Heterocycles 549mentioning

confidence: 99%