Benzene-acetonitrile Mixtures Research Articles

Effect of solvent polarity on the fluorescence quenching of TMC molecule by aniline in benzene–acetonitrile mixtures

The fluorescence quenching of coumarin derivative, 6-methoxy-4-p-tolyloxymethyl-chromen-2-one by aniline is carried out in different solvent mixtures of benzene and acetonitrile at room temperature. The quenching is found to be appreciable and a positive deviation from linearity is observed in the Stern–Volmer plot in all the solvent mixtures. Various rate constants for fluorescence quenching processes have been estimated using a sphere of action static quenching model and a finite sink approximation model. From the positive deviation of linear Stern–Volmer plots and dependence of rate constants on the polarity of the solvents, it has been inferred that the quenching process is diffusion-limited, and static as well as dynamic quenching processes are responsible for the observed positive deviation in the Stern–Volmer plot. Further, both models have been found to agree well with transient state also in pure acetonitrile and benzene solvents.

Role of solvent polarity on the fluorescence quenching of newly synthesized 7,8-benzo-4-azidomethyl coumarin by aniline in benzene–acetonitrile mixtures

The fluorescence quenching of 7,8-benzo-4-azidomethyl coumarin by aniline has been studied in different solvent mixtures of benzene (BN) and acetonitrile (AN) at room temperature. The quenching is found to be appreciable and a positive deviation from linearity was observed in the Stern–Volmer (S–V) plot in all the solvent mixtures. Various parameters for the quenching process have been determined by sphere of action static quenching model and finite sink approximation model. The magnitudes of these rate parameters indicate that positive deviation in the S–V plot is both due to static and dynamic processes.

Fluorescence quenching of BPBD by aniline in benzene–acetonitrile mixtures

The quenching of fluorescence of 2-(4′- t-butylphenyl)-5-(4′′-biphenylyl)-1,3,4-oxadiazole (BPBD) has been studied by aniline in different solvent mixtures of benzene and acetonitrile at room temperature. The quenching is found to be appreciable and a positive deviation from linearity was observed in the Stern–Volmer plot in all the solvent mixtures. Various rate parameters for the quenching process have been determined by sphere of action static quenching model and finite sink approximation model. The magnitudes of these rate parameters indicate that positive deviation in the Stern–Volmer plot is due to both static and dynamic processes. The dependence of Stern–Volmer constant on dielectric constant of the solvent mixture indicates the possibility of different solvent molecule composition around the fluorescent from that of the bulk.

Catalytic effects of hydrogen-bond acceptor solvent on nucleophilic aromatic substitution reactions in non-polar aprotic solvent: reactions of phenyl 2,4,6-trinitrophenyl ether with amines in benzene–acetonitrile mixtures

The effect of addition of small amounts of hydrogen-bond acceptor solvent, acetonitrile, to the benzene medium of the reactions of phenyl 2,4,6-trinitrophenyl ether with aniline and cyclohexylamine, respectively have been investigated. The addition produced similar effects in the two reactions—continuous rate increase with increasing amounts of acetonitrile. The results are interpreted in terms of the effect of amine–solvent interaction on the nucleophilicity of the amines and are in accord with our expectations based on the effects observed for hydrogen-bond donor solvent, methanol on the same reactions. It is also established from the results that the role of hydrogen-bond acceptor co-solvent could be played by an added more basic non-nucleophilic amine.

Titration of Acids and Acid Mixtures in Benzene-Acetonitrile Binary Solvent System

In this investigation, the half-neutralization potential of a series of acids of varying pKa was determined in the benzene-acetonitrile solvent system. The half-neutralization potential value of the acids was related to the pKa in a series of benzene-acetonitrile mixtures covering a range of dielectric constants (Dm = 5–35). The slopes of these straight-line relationships were then related to the dielectric constants of the solvent mixtures. The solvent mixture showing the maximum slope (Dm = 30) was used as a differentiating solvent for titrating binary and ternary sulfonamide mixtures.

Kinetics of reaction of 4-substituted 2-nitrofluorobenzenes with piperidine in benzene-acetonitrile mixtures

Kinetics of reaction of 4-substituted 2-nitrofluorobenzenes with piperidine in benzene-acetonitrile mixtures