The Reaction of 2,4,6-Trinitrotoluene and 2,4,6-Trinitrotoluene- d 3 with Sodium Isopropoxide in Isopropyl Alcohol

Equilibrium constants for the formation of 1 : 1 cyanide ion o-complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitroanisole, and 2,4,6-trinitrotoluene have been determined spectrophotometrically over a range of temperatures. Standard enthalpy ( A H 0 ) and entropy (AS0) changes associated with each reaction have been evaluated. The kinetics of formation of the o-complexes have been investigated by means of a stopped-flow technique and the activation parameters characterizing the formation of each complex have been determined. Evidence is presented which indicates the cyanide ion -2,4,6-trinitroanisole o-complex formed in isopropanol contains the cyanide ion bonded exclusively at the C-3 position.Les constantes dlCquilibres pour la formation d'un complexe-o 1 : 1 ion cyanure -trinitro-1,3,5 benzene, trinitro-2,4,6 anisole et trinitro-2,4,6 toluene ont t t t dtterminies dans un intervalle d e temptratures a I'aide de la spectrophotornCtrie. Les changements d'enthalpie standard (AH0) et d'entropie (AS0) associCs a chaque reaction ont Ctt Cvalues. La cinktique de formation des complexes-o a 6t6 ttudite a I'aide de la technique a dtbit interrompu et les parametres d'activation se rattachant a la formation de chaque complexe ont ete dtterminks. On apporte des preuves pour montrer que le complexe-cr ion cyanuretrinitro-2,4,6 anisole form6 dans I'isopropanol contient I'ion cyanure lie exclusivement a la position C-3.[Traduit par le journal]Can. J. Chem., 52,8 (1974)

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confidence: 90%

Kinetic and Equilibrium Studies of the Reactions of Cyanide Ion with 1,3,5-Trinitrobenzene, 2,4,6-Trinitroanisole, and 2,4,6-Trinitrotoluene in Isopropanol

Gan¹,

Norris²

1974

“…The reaction of I ,1,3,3-tetramethylguanidine (TMG) with 2,4,6-trinitrotoluene (TNT) in dipolar aprotic solvents has been shown to be a proton transfer from the methyl group ( I , 2), and a number of primary deuterium kinetic isotope effects have been measured for the proton transfer reaction with various bases and solvents (3)(4)(5)(6)(7). Nevertheless, it has also been noted (3,6,7) that nucleophilic attack by some bases could take place on the benzene ring to yield a a-complex.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, it has also been noted (3,6,7) that nucleophilic attack by some bases could take place on the benzene ring to yield a a-complex. The ring attack took place at the 3 position instead of the I position as originally observed by Meisenheimer (8).…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanisms of the reaction of 2,4,6-trinitrocumene and 2,4,6-trinitroethylbenzene with 1,1,3,3-tetramethylguanidine in N,N-dimethylformamide solvent

Biswas¹,

Jarczewski²,

Leffek³

1987

The reaction of tetramethylguanidine (TMG) with trinitrocumene (TNC) and trinitroethylbenzene (TNEB) in dimethylformamide solvent has been studied with respect to products and kinetics. For TNC only u-complex formation with the benzene ring was observed, for which theequilibrium constant, rate constants, and activation parameters were measured. For TNEB, both u-complex formation and proton transfer from the a-carbon atom of the ethyl group were observed. The equilibrium constants, rate constants, and activation parameters were separately determined for each reaction and a primary deuterium isotope effect, kH/kD = 13.6 (at 20°C), was found for the proton transfer. The reaction parameters are compared to those for proton transfer from TNT to tetramethylguanidine in DMF solvent.MIHIR K. BISWAS, ARNOLD JARCZEWSKI et KENNETH T. LEFFEK. Can. J. Chem. 65, 1007Chem. 65, (1987 Dans le but de determiner la cinttique et la nature des produits des rtactions, on a ttudit les rtactions de la tttramtthylguanidine (TMG) avec le trinitrocumkne (TNC) et avec le trinitrotthylbenzkne (TNEB), dans le dimtthylformamide. Dans le cas du TNC, on n'a observt que la formation du complexe u avec le noyau benztnique dont on a mesurt la constante d'tquilibre, les constantes de vitesses ainsi que les parametres d'activation. Dans le cas du TNEB, on a observk la formation d'un complexe a ainsi qu'une rtaction de transfert de proton du carbone u du groupement tthyle. Pour chacune de ces rkactions, on a dttermint les constantes d'tquilibre, les constantes de vitesse et les paramktres d'activation; de plus, on a trouvt que l'effet isotopique primaire du deutkrium, kH/kD = 13,6 (a 20°C). On a compart les paramktres rtactionnels avec ceux observts anttrieurement pour le transfert de proton du TNT i la tttramtthylguanidine dans le DMF.[Traduit par la revue]

“…Hence it appeared that a unique theory for this phenomenon could not apply and several proposals evolved to account for its origin (vide infra). It occurred to us that structural modification could produce useful information and, while use of alkyl substituted nitroaromatics could be considered, study of 2,4,6-trinitrotoluene has shown that alkoxide ion can partake in proton abstraction to give a nitrobenzylic anion in addition to a-complex formation (16)(17)(18)(19). On the other hand, use of 1-phenyl-2,4,6-trinitrobenzene (4) would preclude proton abstraction from occurring, while providing a model to test the importance of steric and delocalization effects.…”

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confidence: 99%

Ambident nucleophilic reactivity in σ-complex formation. Part 5. Reaction of 1-phenyl-2,4,6-trinitrobenzene with methoxide and phenoxide ions

Buncel¹,

Murarka²,

Norris³

1984

NORRIS. Can. J . Chem. 62, 534 (1984).The reactions of 1-phenyl-2,4,6-trinitrobenzene (4) with methoxide and phenoxide ions in DMSO and DMSO-methanol solutions have been investigated. MeO-gives rise to a 1,3 adduct through kinetic control and a 1,l adduct through thermodynamic control. These processes persist also in the reaction of 4 with potassium phenoxide in DMSO-methanol. However, reaction of 4 with potassium phenoxide in DMSO gives rise to a 1,3 adduct as the only observed species in which phenoxide is bonded to the nitroaromatic moiety via the para phenoxy carbon, in accord with previous observations on the ambident reactivity of phenoxide ion. The results are considered in terms of various steric and electronic effects and it is concluded that F-strain, relief of steric compression, and delocalizability considerations play dominant roles in accounting for the observed reaction course.ERWIN BUNCEL, SURESH KUMAR MURARKA et ALBERT RICHARD NORRIS. Can. J. Chem. 62, 534 (1984) On a CtudiC les reactions du phtnyl-l trinitro-2,4,6 benzkne (4) avec les ions methanolates et phenolates en solution dans le DMSO et dans le melange DMSO-methanol. L'ion MeO-donne des adduits 1,3 qui sont des produits de contrBle cinktique et des adduits 1 ,I rtsultant du contrBle thermodynamique. Ce processus se manifeste Cgalement dans la reaction du compose 4 avec le phenolate de potassium dans le melange DMSO-mtthanol. Cependant, cette m&me rtaction effectuee dans le DMSO conduit a un adduit 1,3; c'est la seule espkce observee dans laquelle I'ion phtnolate est lie a la portion nitroaromatique par I'intermediaire du carbone en position para du groupe phtnoxy en accord avec les observations anterieures relatives a I'ion phtnolate qui posskde deux positions de reaction. On considkre ces rksultats en fonction des effets stCriques et tlectroniques et on conclut que I'encombrement F, la dCcompression sterique et la possibilite de dClocalisation jouent un rBle majeur dans I'evolution de la rtaction.[Traduit par le journal]As part of a continuing study on the interactions of nitroaromatic compounds with bases (1-3), in this paper we present results pertaining to the formation of 1,l and 1,3 a-complexes and the ambident reactivity of phenoxide ion (4).Among the various structure-reactivity relationships in a-complex formation processes (5-1 l), one which has received considerable attention is the generally observed kinetic preference for 1,3, and thermodynamic preference for 1,l adduct formation, in the reactions of bases with 1-X-2,4,6-trinitrobenzenes and related substrates. The first instance of this type of result was the discovery by Servis in 1965 (12) through 'H nmr spectroscopy that 2,4,6-trinitroanisole (TNA, I), on reaction with methoxide ion in dimethyl sulfoxide (DMSO) -methanol solution (90: 10 v/v), yielded initially the 1,3 adduct (2), which then decayed and was replaced by the more stable 1,l adduct (3), Scheme 1.While in the majority of subsequent studies this trend in kinetic versus thermodynamic control was confirmed...