Mixtures Of Benzonitrile Research Articles

Influence of dielectric, Electro-Optic Kerr Effect and spectroscopic characterisation on polar–polar binary liquid mixture

ABSTRACT Complex dielectric spectra of the binary mixture of benzonitrile (BNZ) with acetophenone (ACPH) have been carried out at 11 different concentrations in the frequency range of 10 MHz to 40 GHz at four different temperatures (10°C, 15°C, 20°C and 25°C) using Time Domain Reflectometry technique. Static dielectric constant (ε0), relaxation time (τ) are obtained for above mentioned temperatures using nonlinear least squares fit method and density and refractive index are obtained at room temperature (25°C). These parameters are used to calculate the excess static dielectric constant (ε0 E) and excess inverse relaxation time (1/τ)E, excess molar volume (Vm E), effective Kirkwood correlation factor (geff), Bruggeman factor (fB) and thermodynamic parameters such as enthalpy and entropy of activation of BNZ-ACPH mixture. Static dielectric constant decreases with increasing temperature and increasing concentration of ACPH in BNZ. The deviance in the excess parameters shows the strength of the molecular interactions and the presence of intermolecular interaction between unlike molecules. The measurement of Kerr constant (B) of the binary mixture of BNZ-ACPH have been reported for the wavelengths 632.8 nm and 512 nm for 5 different concentrations at room temperature using Electro-Optic Kerr Effect method. The change in the Kerr constant was observed for the different concentrations associated with the pure liquids. This deviation shows the non-additive behaviour and which is in good agreement with the dielectric parameters of the system under study. Also, the FTIR spectra have been obtained of BNZ-ACPH mixture to have a good agreement with the dielectric study.

The application of a supported palladium catalyst for the hydrogenation of aromatic nitriles

The use of a Pd/C catalyst in the liquid phase hydrogenation of various aromatic nitriles (benzonitrile, benzyl cyanide, 3-phenyl propionitrile and cinnamonitrile) has been studied in order to assess the effectiveness of this type of catalyst for this class of reaction. On modifying the nitrile substituent and upon introducing conjugation, varying degrees of conversion are observed. For benzyl cyanide and 3-phenylpropionitrile, incomplete mass balance profiles are linked to spill-over to the carbon support. In the case of benzonitrile hydrogenation, a hydrogenolytic step leads to a loss of selectivity to the primary amine to yield toluene with, ultimately, complete selectivity. Co-hydrogenation measurements on mixtures of benzonitrile and benzylamine indicate the presence of site-selective chemistry. Co-hydrogenation studies on mixtures of benzonitrile and benzyl cyanide highlight the competitive nature of the reaction system and, indirectly, establish a contribution from adsorbed imine species.

Microwave-Assisted Facile and Convenient Synthesis of Imidazolines.

The 2-substituted imidazolines are of considerable importance because their derivatives exhibit a wide variety of biological activities, including antihypercholesterolemic, antiinflammatory, antidiabetic and antihypertensive. These compounds are also used as intermediates and catalysts in synthetic chemistry. Several methods for the synthesis of 2-imidazolines from carboxylic acids, esters, nitriles, orthoesters, hydroximoyl chlorides, hydroxy amides, and mono-, or disubstituted chlorodicyanovinyl benzene have been reported previously. However, some of these methods suffer from disadvantages such as long reaction times, low yields of the products, difficulty in preparation of starting materials and tedious workup. Therefore, there is still a scope to find potential methods for this transformation. In recent years organic reactions assisted by microwave irradiation have gained special attention. The chief features of the microwave reactions are the enhanced selectivity, much improved reaction rates, milder reaction conditions and formation of cleaner products. In this paper we wish to report an efficient and convenient method for the synthesis of 2-imidazolines from nitriles and ethylenediamine in the presence of sulfur under microwave irradiation (Scheme 1). Typically, benzonitrile (1a), ethylenediamine and sulfur were mixed and irradiated for 2.5 min in a domestic microwave oven (operating at 720 W). The reaction mixture was allowed to reach to room temperature, then cold water was added and the mixture was extracted with chloroform. Removal of the solvent and recrystallization of the crude product from cyclohexane gave the corresponding 2imidazoline (2a) in 97% yield. The effect of microwave irradiation power in this reaction was also investigated. The results show that the highest yield of compound 2a is obtained at a power of 720 W (Table 1). At this power, the temperature of the reaction vessel after the irradiation was measured to be ~130 °C. Under the same reaction conditions, a variety of nitriles are cleanly and rapidly converted to their corresponding 2-imidazolines in 96-99% yields within 1.211 min (Table 2). The conventional thermal reactions were also performed for this transformation in the absence of microwave energy. The experimental results show that the yields of the products are relatively lower under this condition and the reaction times are longer, specially in the cases of 1b, 1h and 1j. In order to show the general applicability of this method, the reaction of benzonirtile was performed on a 100 mmole scale. The result (95% yield, 2.5 min) was comparable to that obtained by the small scale experiment. In order to show the effect of sulfur, a mixture of benzonitrile (1a) and ethylenediamine was irradiated in the absence of sulfur. Under this condition, the reaction did not proceed at all and benzonitrile remained intact in the reaction mixture. The exact mechanism of the reaction is not clear at this time. However, a plausible explanation is that sulfur reacts with nitrile to produce thioamide. Thioamide reacts with ethylenediamine, which upon elimination of hydrogen sulfide and ammonia, produces 2-imidazoline. Evolution of hydrogen sulfide is a certification of the above statement. In conclusion, a simple and efficient procedure for the synthesis of 2-imidazolines has been explored. Mild reaction conditions, absence of solvent, shorter reaction time, easy and quick isolation of the products and excellent yields are main advantages of this procedure which make this method an attractive and useful contribution to the present methodologies.

Microwave-Assisted Facile and Convenient Synthesis of Imidazolines

The 2-substituted imidazolines are of considerable importance because their derivatives exhibit a wide variety of biological activities, including antihypercholesterolemic, antiinflammatory, antidiabetic and antihypertensive. These compounds are also used as intermediates and catalysts in synthetic chemistry. Several methods for the synthesis of 2-imidazolines from carboxylic acids, esters, nitriles, orthoesters, hydroximoyl chlorides, hydroxy amides, and mono-, or disubstituted chlorodicyanovinyl benzene have been reported previously. However, some of these methods suffer from disadvantages such as long reaction times, low yields of the products, difficulty in preparation of starting materials and tedious workup. Therefore, there is still a scope to find potential methods for this transformation. In recent years organic reactions assisted by microwave irradiation have gained special attention. The chief features of the microwave reactions are the enhanced selectivity, much improved reaction rates, milder reaction conditions and formation of cleaner products. In this paper we wish to report an efficient and convenient method for the synthesis of 2-imidazolines from nitriles and ethylenediamine in the presence of sulfur under microwave irradiation (Scheme 1). Typically, benzonitrile (1a), ethylenediamine and sulfur were mixed and irradiated for 2.5 min in a domestic microwave oven (operating at 720 W). The reaction mixture was allowed to reach to room temperature, then cold water was added and the mixture was extracted with chloroform. Removal of the solvent and recrystallization of the crude product from cyclohexane gave the corresponding 2imidazoline (2a) in 97% yield. The effect of microwave irradiation power in this reaction was also investigated. The results show that the highest yield of compound 2a is obtained at a power of 720 W (Table 1). At this power, the temperature of the reaction vessel after the irradiation was measured to be ~130 °C. Under the same reaction conditions, a variety of nitriles are cleanly and rapidly converted to their corresponding 2-imidazolines in 96-99% yields within 1.211 min (Table 2). The conventional thermal reactions were also performed for this transformation in the absence of microwave energy. The experimental results show that the yields of the products are relatively lower under this condition and the reaction times are longer, specially in the cases of 1b, 1h and 1j. In order to show the general applicability of this method, the reaction of benzonirtile was performed on a 100 mmole scale. The result (95% yield, 2.5 min) was comparable to that obtained by the small scale experiment. In order to show the effect of sulfur, a mixture of benzonitrile (1a) and ethylenediamine was irradiated in the absence of sulfur. Under this condition, the reaction did not proceed at all and benzonitrile remained intact in the reaction mixture. The exact mechanism of the reaction is not clear at this time. However, a plausible explanation is that sulfur reacts with nitrile to produce thioamide. Thioamide reacts with ethylenediamine, which upon elimination of hydrogen sulfide and ammonia, produces 2-imidazoline. Evolution of hydrogen sulfide is a certification of the above statement. In conclusion, a simple and efficient procedure for the synthesis of 2-imidazolines has been explored. Mild reaction conditions, absence of solvent, shorter reaction time, easy and quick isolation of the products and excellent yields are main advantages of this procedure which make this method an attractive and useful contribution to the present methodologies.

Ultrasonic velocity, permittivity, density, viscosity and proton nuclear magnetic resonance measurements of binary mixtures of benzonitrile with organic solvents

The ultrasonic velocity, permittivity, density and viscosity of binary mixtures of benzonitrile (BN) with methanol (MeOH), acetone (AC), acetonitrile (AN), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridine (Py) and carbon tetrachloride (CCl4) have been measured at 25 °C. Ultrasonic velocity measurements of BN–MeOH, BN–CCl4, BN–AN, AN–MeOH and CCl4–MeOH mixtures have also been made at 35 and 45 °C. The excess permittivity (ΔIµ), excess viscosity (Δη) and excess isentropic compressibility (Δκs) for various systems have been calculated and examined as a function of solvent composition. The excess parameters show strong deviations from ideal behaviour and indicate interactions between BN and most of these organic solvents. Mixtures of BN and DMF, however, show nearly ideal behaviour over the entire range of composition. The nature of interaction of BN with methanol is different and more interesting than for other solvents. BN, like CCl4 and AN, is a strong structure breaker of methanol. Proton NMR chemical shift measurements of the OH proton of methanol in BN–MeOH mixtures confirm this observation.

ChemInform Abstract: CROWN ETHERS IN ORGANIC SYNTHESIS. II. CATALYTIC DEHYDRATION OF ALDOXIMES

AbstractBenzaldoxim (I) wird in Gegenwart von (II) und Kaliumcyanid sowie einem 18‐Kronenether als Katalysator zu Benzonitril (III) und (IV) im Verhältnis 3:1 umgesetzt.

CROWN ETHERS IN ORGANIC SYNTHESIS. II. CATALYTIC DEHYDRATION OF ALDOXIMES

Abstract Phase transfer (crown ether or quaternary ammonium salt) catalyzed reaction of benzaldoxime with potassium salts (cyanide or halide) produces a 3:1 mixture of benzonitrile and benzamide. A base-catalyzed mechanism is proposed. Extension of the procedure to provide a general, one-pot conversion of aldehydes to nitriles is indicated.

還元的アチルアミン化の研究 (第7報)

1) Reduction, at high temperature and high pressure, of benzonitrile in the presence of benzaldehyde results in an increased yield of dibenzylamine because the aldehyde takes part in the latter's formation.2) The action of formamide or ethyl formate was examined by the reductive formyl-amination of a mixture of benzaldehyde and benzonitrile. In the case of formamide, formylbenzylamine can be obtained in 89% yield, in a mixture of benzonitrile and benzaldehyde in a molar ratio. The use of benzaldoxime and ammonia, instead of benzonitrile, was also experimented.