Benzotriazole Molecules Research Articles

Using Polarised, Ultra-Soft X-Ray Absorption Spectroscopy to Probe Molecular Orientation in Benzotriazole Films Adsorbed on Partly Oxidised Copper

Abstract Data are presented of polarisation studies carried out to elucidate the orientation of the benzotriazole molecule adsorbed onto copper thin films. Spectra were obtained at the carbon K-edge. Comparisons are made between this and the orientations of structurally similar molecules; indazole, methyl benzotriazole and benzimidazole. Different copper film thicknesses and degrees of oxidation were investigated, and a film of benzotriazole on silver was also examined. All of the molecules were found to be oriented normal to the substrate, except benzimidazole on copper, which showed no orientation dependence.

A Novel Route to N-Styrylamides

Abstract A general synthesis of N-styrylamides starting from amides and phenylacetaldehyde is described. Condensation of the amide, aldehyde and benzotriazole affords N-(1-benzotriazol-l-yl-2-phenylethyl)amides 2 from which the benzotriazole molecule is smoothly eliminated.

Adsorption and film growth of BTA on clean and oxygen adsorbed Cu(110) surfaces

Benzotriazole (BTA) adsorption on clean Cu(110) and oxygen reconstructed Cu(110)−2 × 1 and c(6 × 2) surfaces has been investigated by scanning tunneling microscopy (STM). The STM images show that BTA forms the c(4 × 2) commensurate phase on the clean Cu(110)−1 × 1 surface. On the other hand, STM images of BTA adsorbed on the oxygen-induced Cu(110)−2 × 1 surface show a fully disordered structure. From a kinetic point of view, BTA molecules should adsorb preferentially on the oxygen-induced Cu(110)−2 × 1 added row compared to the clean Cu(110) surface.

Anodic Polarization Behavior of Copper in Aqueous Bromide and Bromide/Benzotriazole Solutions

Theoretical potential‐pH equilibria and anodic polarization studies were used to show that formation of the aqueous complex in at ∼24°C promotes active behavior of copper at in a manner similar to that observed in chloride solutions. A region of apparent Tafel behavior is observed with a position and slope of 60 mV that is consistent with mass transport control of the species. Careful analysis of this region provides a method for checking the value of the chemical‐free energy of the cuprous complex. Polarization studies in benzotriazole containing show that benzotriazole interacts with the active oxide‐free copper surface to inhibit anodic dissolution of copper. The interaction is potential‐dependent, similar to the behavior in chloride solutions, and inhibition is less effective at the lower pH values. Furthermore, a potential occurs above which the spontaneous repair of a damaged inhibiting film is unlikely. The inhibition process is discussed and the observations are shown to be reasonably consistent with a mechanism whose first step is the adsorption of the neutral benzotriazole molecule. Some possible similarities and differences between the active behavior of copper in iodide and bromide solutions are discussed on the basis of differences in their potential‐pH equilibria.

Functional Polymers. LIX. Synthesis and Polymerization of 2(2-Hydroxyphenyl)2H-benzotriazole-Based Glycidyl Methacrylate Derivatives

Abstract Three 2(2,4-dihydroxyphenyl)2H-benzotriazole derivatives were reacted with glycidyl methacrylate on the 4-hydroxyl group of the benzotriazole molecules to give the corresponding acrylic monomers. The new monomers were copolymerized with methyl methacrylate. In another approach, copolymers of methyl methacrylate and glycidyl methacrylate were allowed to react with the same three 2(2,4-dihydroxyphenyl)2H-benzotriazole derivatives and gave the corresponding 3-methacryloxy-2-hydroxypropyl derivatives. The monomers and polymers were characterized by the usual characterization techniques. The greatest emphasis was placed on the ultraviolet spectra in various solvents stressing the local proximity of the neighboring groups.

Spectroscopy of jet-cooled benzimidazole and benzotriazole

Laser-induced fluorescence excitation and dispersed fluorescence spectra of jet-cooled benzimidazole and benzotriazole molecules are reported. The first excited singlet state is assigned to 1L b for benzimidazole (origin at 36032 cm −1) and to 1L a for benzotriazole (origin at 34927 cm −1). A rapid nonradiative decay is found to occur for benzotriazole above 1200 cm −1 from S 1 origin. The spectra of benzimidazole show a good Franck—Condon overlap between S 0 and S 1( 1L b) states. For benzotriazole progressions of several in-plane modes (540, 1153, 1242, 1405 and 1447 cm −1) cover about 8000 cm −1 of the dispersed fluorescence spectrum following excitation into the origin of the S 1( 1L a) state.

Application of X-ray absorption spectroscopy to the structural characterisation of monodispersed benzotriazole coatings on partly oxidised copper thin films

X-Ray absorption spectroscopy using synchrotron radiation has been used to probe the structure of Copper-benzotriazole complexes and that of the benzotriazole involved in surface films following adsorption onto partly oxidised Cu thin films. Data recorded at the Cu-K edge and, using 4- and 5-bromo-substituted benzotriazole, at the Br-K edge are consistent with the CuI atoms coordinated to three or four benzotriazole molecules through the N(2) position on the triazole ring. Examination of the thin films using glancing-angle geometry suggests the adsorbed film to be only a few monolayers in thickness with the benzotriazole molecules coordinated to CuI ions in the oxidised Cu surface forming a hydrogen-bonded surface complex similar, in part, to that proposed by Fang et al. (Surf. Sci., 1986, 176, 476). At the interface the surface reaction appears to involve a topotactic arrangement with the (100) plane of Cu2O where the in-plane Cu–Cu interatomic distances closely match that expected for the surface complex. The overall limitations of the glancing-angle technique to the characterisation of this kind of interfacial system are discussed.

Anodic Polarization Behavior of Copper in Aqueous Chloride/Benzotriazole Solutions

Potential‐pH equilibria and potentiodynamic polarization studies were used to confirm that formation of complexes in and solutions produces a range of potentials at which anodic dissolution of copper occurs without formation of oxide. The interaction of benzotriazole (1 g/l) with oxide‐free copper surfaces in the chloride solutions was studied by potentiodynamic polarization and potentiostatic techniques. Inhibition of the anodic dissolution reaction was obtained in near‐neutral pH solutions and at pH 3.0. Inhibition was ineffective at pH 1.0. The interaction of benzotriazole with oxide‐free surfaces, leading to inhibition, was potential‐ and time‐dependent. Also, a limiting potential was observed and predicted above which additions of benzotriazole are ineffective and above which existing inhibiting films cannot undergo spontaneous repair. The results confirm that benzotriazole can interact with oxide‐free surfaces to promote corrosion inhibition of copper. The characteristics of the inhibition behavior, including breakdown and pH effects, were consistent with an inhibiting film that formed by adsorption of neutral benzotriazole molecules onto the Cu surface, followed by the adsorption of a thin layer of cuprous benzotriazole in polymeric form.

Methyl Substitution in Benzotriazole and Its Influence on Surface Structure and Corrosion Inhibition

Fourier transform infrared reflection absorption spectroscopy (FT‐IRAS) and polarization resistance measurements have been used to investigate the surface structure and inhibiting properties of all four monosubstituted methylbenzotriazoles on copper surfaces. The formation of a protective barrier layer is strongly dependent on the position of the methyl group in the benzotriazole (BTA) molecule as well as on the presence of a cuprous oxide on the copper surface. Substitution of a methyl group in the triazole ring, 1Me‐ or 2Me‐BTA, prevents the formation of a protective layer on the surface, whereas introduction of a methyl group in the benzene ring, 4Me‐ and 5Me‐BTA results in the formation of stable layers, 30 and 70Å, respectively. The inhibiting efficiencies for 4Me‐ and 5Me‐BTA are even higher than for BTA itself. It is concluded from a comparison with BTA that other parameters than film thickness and surface orientation must be taken into account in order to explain the differences in inhibiting properties. The increased hydrophobic character of the methyl substituted BTA derivatives may explain their superior inhibiting efficiencies in relation to BTA.

IR reflection-absorption spectroscopic study of benzotriazole on copper

Polarization-modulated infrared reflection absorption spectroscopy has been used to measure the infrared spectra of the surface films on copper grown in methanol or aqueous solutions containing benzotriazole. The spectra were compared with that of the copper-benzotriazole model complex. Surface protective films prepared in methanol containing benzotriazole are composed of infinite chains in which the Cu-benzotriazole complex is connected by strong charge-transfer interactions between benzotriazole molecules.

Benzotriazole as a corrosion inhibitor for brass

The effect of benzotriazole (BTA) on the corrosion of brass in 0.1 N HCl, 0.1 N H 2SO 4 and 0.1 N NH 4Cl was studied by means of immersion tests and galvanostatic measurements. BTA showed a good inhibition effect in some corrosive media. The percentage inhibition in 0.1 N HCl solution was found to increase with increasing BTA concentration. In contrast, the percentage inhibition in 0.1 N H 2SO 4 was inversely proportional to the BTA concentration. The highest inhibition efficiency was obtained in 0.1 N NH 4Cl. The role of BTA as an inhibitor for brass was explained in terms of the chemisorption of BTA molecules at some active sites on brass surfaces.