Benzoic acid, adsorption

Waszczuk etal. [173] have performed radiometric and voltammetric studies of benzoic acid adsorption on a pc-Ag electrode in contact with 0.1 M HCIO4 solution. The electrodes were obtained by electroplating Ag black onto a vacuum-deposited silver substrate. Benzoic acid appeared to be surface active in the entire range of potentials available at Ag in aqueous solutions. Adsorption of benzoic acid increased as the potential became more positive and this surface process was... 

Hagaman, E.W., Chen, B., Jiao, J., and Parsons, W. 2012. Solid-state O NMR study of benzoic acid adsorption on metal oxide surfaces. Solid State Nucl. Magn. Reson. 41 60-67. 

Basic properties of alkaline earth oxides have been measured by different methods such as titration with benzoic acid, adsorption of CO2, and others. Basicity distributions measured by the titration of outgassed samples of MgO, CaO and SrO are shown in Fig. 3.5. Magnesium oxide and CaO possess base sites stronger than H =26. 

FIG. 25 Adsorption isotherm for benzoic acid adsorption on alumina at pH = 5.0. Data points from Kummert and Stumm [19]. Regression line fit for Eq. (329) with tabulated regression parameters. 

In Table 14, the parameters determined for benzoic acid adsorption on alumina are contrasted. The values of Kummert and Stumm were determined fl-om a simultaneous solution of multiple adsorption equations, so critical comparison of the adsorption parameters in Table 14 based on the two methods is difficult. It will simply be... 

The requirement for atomic-scale sites in the CT mechanism is thought to be due to the formation of adatom-adsorbate complexes. Such complexes require a coordination site on the adsorbate through which the strong interaction can occur, as was demonstrated by the controlled adsorption of isonicotinic acid and benzoic acid on thin island films of silver (see the work of Chen et ai, 1980). This clearly showed that SERS spectra could only be obtained from the molecules when coordinating sites were exposed to the Ag film. 

Purification. See also Impurities Refining Wastewater treatment Water purification adsorbents for, 7 612 adsorption processes for, 7 612-613 aminophenols, 2 660-661 benzoic acid, 3 627-628 of carbide-generated acetylene, 7 207-208... 

Adsorption of benzoic acid (BA) was studied on four face-centered... 

Hartman, R.J., Kern, R.A., andBobalek, E.G. Adsorption isotherms of some substituted benzoic acids,/. Colloid Sci., 1(3) 271-... 

From this point of view, a brief comparison of acyloxylation of cis- or irany-stilbenes in electrochemical and chemical conditions is also relevant. Oxidation of cis- or irany-stilbene at the platinum anode in the presence of acetic or benzoic acid gives predominantly meyo-diacylates of hydroxy-benzoin or, if some water is present, t/treo-monoacylate. None of the stereoisomeric erythro-mono-acylate and rac-diacylate were obtained in either case. There was no evidence of isomerization of cis- to trany-stilbene nnder the electrolytic conditions employed (Mango and Bonner 1964, Koyama et al. 1969). The sequence of reaction steps in Scheme 2.27 was proposed. Adsorption-controlled one-electron oxidation of the snbstrate takes place. Then the cis-stilbene cation-radical interact with acetate to form an oxonium ion. The phenyl groups in the oxoninm adopt the trans mntnal disposition which is thermodynamically preferential. The trany-benzoxoninm ion is the common intermediate for conversions of both cis- and trany-stilbenes and, of conrse, for all the final prodncts (Scheme... 

In acidic media, the extent of adsorption of para-substituted benzoic acid on ferri-hydrite and goethite depends on the nature of the substituent (Rung and McBride, 1989). Adsorption decreases in the order ... 

Equation 10.27 is generally known as Freundlich equation. Equation 10.27 with concentration replaced by pressure was also used to describe the adsorption isotherms of gases on solids, suggesting the incorrect idea that adsorption from solution by a solid could be paralleled with gas or vapor adsorption on the same adsorbents. Whereas in some cases the restriction to dilute solutions was imposed by the solubility of solids (e.g., benzoic acid in water or stearic acid in benzene) it was not imposed on the investigation of mixtures of completely miscible liquids, e.g., acetic acid in water. 

Although in part this order may be affected by subsequent reaction of the iodine with the organic solvent under the influence of catalytic material in the charcoal (Schmidt, Z it KoUoid. Ghem. XIV. 242, 1914) yet similar alterations have been noted by Freundlich (ibid. p. 260) with other solutes, e.g. benzoic and picric acids, who found the following order for decreasing adsorption for benzoic acid water, benzene, ethyl ether, acetone for picric acid, water, ethyl, alcohol, benzene. 

Similar studies were carried out with benzoic acid on porous palladium electrodes [150]. The objective of this work was to investigate the adsorption processes and the reactivity of benzoic acid on different noble metals, in order to compare these results with those obtained for related aromatic compounds. On-line mass spectroscopy analysis of volatile products revealed that the adsorption of benzoic acid is irreversible at platinum while it is mainly reversible on palladium. Accordingly, different catalytic activity of platinum and palladium was found in the electrooxidation. 

Zelenay etal. have applied CV and radiotracer technique to study adsorption of benzoic acid from 0.1 M HCIO4 solution on a pc-Au electrode prepared by electroplating [286]. Chemisorption occurred within the entire potential range... 

This local adsorption geometry for formate on Cu(100) and Cu(110), with the molecular plane perpendicular to the surface and bonding through the two carboxylate atoms in near-atop sites, is also seen in other simple carboxylate species adsorbed on Cu(110), notably acetate (CH3COO—) [103] and benzoate (CgFIjCOO—) [104] formed, respectively, by exposure to acetic acid and benzoic acid. Relatively recent X-ray spectroscopy measurements combined with theoretical calculations provide further information on the bonding of formate and acetate on Cu(110) [105]. 

Fig. 6.117. Adsorption isotherms for various organic species on platinum in 0.01 N HCI solution, obtained with the radiotracer technique valeric acid (a), butanol ( ), benzoic acid (a), naphtoic acid ( ), naphtol (O). All the data are taken at the maximum adsorption potential. (Reprinted from J. Jeng, dissertation, Texas A M University, 1991.)...

The maximum surface concentration of benzoic acid obtained by extrapolation of the experimental data is rmax = 5.1 X 1014 molecules cm-2. Determine the parameters P and A in the Frumkin equation of adsorption. Calculate the Gibbs energy of adsorption. Compare the results with the Langmuir isotherm. (Sobkowski)... 

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