Infrared spectroscopy acyl compounds

Applications in infrared spectroscopy A and B bands, iron-coordinated CO, 232, 186-187 application to allosteric mechanisms, 249, 566 bacteriorhodopsin, 246, 9, 380-381 caged compounds, 246, 6, 520-521 DNA [base pair formation, 246, 506 conformation, 246, 506-507 denaturation thermodynamics, 246, 506 ligand interactions, 246, 6, 507 sample requirements, 246, 506] fatty acyl ester determination in small cell samples, 233,... 

IR Spectra Infrared spectroscopy is of considerable importance in identifying carboxylic acids and their derivatives. The C = 0 stretching band is one of the most prominent in their IR spectra since it is always a strong band. Figure 17.2 gives the location of this band for most acyl compounds. 

Infrared spectroscopy is useful for classifying acyl compounds. 

Infrared spectroscopy has also been used to follow reactions between surface hydroxyls and organic compounds, such as alcohols and alkyl or acyl halides, to give covalent Si—O—R or Al—O—R bonds (McDonald [1958] Uytterhoeven et al. [1959] Fripiat et al. [1960b] UvAROV [1963] Boreskov et al. [1964] CoRSO [1964]). Reaction between alumina and alcohols at elevated temperatures has been shown to lead to carboxylate absorption bands, indicating oxidation of the alcohols by adsorbed oxygen (Boreskov et al. [1964] Corso [1964]). Reaction of phosphates with aluminum and iron hydroxides have been studied by Gastuche et al. [1963]. 

Burton and Praill were the first to prqjare this ecies both by the interaction of perchloric acid with acetic anhydride and the metathetic reaction of sflver perchlorate with acetyl chloride , in a comprehensive study of acylation reactions. They did not attempt a characterisation of the compound and assumed that in acid solutions it existed in a fully ionised form. A few years later, Jander and Surawski followed the formation of acetyl perchlorate in acetic anhydride by measuring the electrical conductivity changes which took place when acetyl bromide was added to silver perchlorate or vice versa. In both titrations an inflection point was observed for a mixture of equimolar quantities of the two reactants indicating the formation of acetyl perchlorate. Moreover, it was clearly drown that this compound was at least partly ionised since its conductivity was higher than that of acetyl bromide. Avedikian and Commeyras characterised acetyl perchlorate by infrared and Raman spectroscopy both in acetic anhydride and carbon tetrachloride. They concluded that some ionisation was present but could not assess its extent. Molecular acetyl perchlorate was also detected. As far as we are aware, no other study of the structure and extent of dissociation of acetyl perchlorate in solution has been conducted. 

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