Cinnamic acid adsorption

Reaction of cinnamic acid, which has the IR and 1II NMR spectra shown in Figures 11.36-11.38, with BH3 THF gives rapid consumption of the starting material. A single product P4 is formed that has die spectra shown. Comparison of die IR spectra shows diat the double bond in the reactant (1630 cm 1) is intact in the product (1654 cm ) but moved to higher frequency. The product P4 also has bodi vinylic (3026 cm1) and saturated (2861 cm1) C-H bonds. Both reactant and product have an O-H adsorption, but the strong H bonding in... 

Such electronic transfer induced by sulfur adsorption was also pointed out by using cinnamic acid as a probe molecule (48). The UV-visible reflexion spectra of adsorbed cinnamic acid on nonpoisoned and partly poisoned platinum catalysts shows that adsorption on pure platinum induces a shift of the peaks toward the higher wavelengths and an appearance of fine structure. Sulfurization of platinum induces a further enhancement of higher wavelength peaks. Binding energy of cinnamic acid is thus increased by sulfur adsorption on Pt catalysts. 

Baizer and coworkers established the most brilliant industrial electroorganic synthesis of the hydrodimerization of acrylonitrile to adiponitrile. They extended this hydrodimerization to a variety of activated olefins and in some cases [41 3] paid attention to the stereochemistry of products. However, their stereochemical data were not enough to discuss the stereochemical course of the reaction. Afterward, an attempt was made to provide a working hypothesis in the hydrodimerization of cinnamates by considering an orientated adsorption of radical anion intermediates on a cathode surface, but this was not persuasive because of a lack of experimental data on the stereochemistry of both the starting olefins and products. Recently Utley and coworkers [44-46] have reported stereochemical data of hydrodimers derived from a variety of cinnamic acid esters with chiral alcohol components. 

Yet another important area of application is the clarification and deacidification of fruit juices, for example, pineapple [187] and apple [188], as well as the adsorption of polyphenols (catechins, flavans, proanthocyanidins, cinnamic acids, etc.) in white wine, responsible for browning and maderization [189]. 

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