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a-Aluminas are readily dissolved in concentrated phosphoric acid for analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES). The dissolution rate is significantly faster than with concentrated HCI at high pressure or via fusion techniques. In addition t o the ICP-AES results obtained with these solvent systems, the results of NMR spectrometric analyses are presented, which permit the preliminary characterisation of the species in the phosphoric acid solutions.

ABSTRACT27Al NMRsp ectra were obtained on a series of alumina sols prepared by the hydrolysis of aluminum sec-butoxide. Subtle but distinct differences were observed in the solution 27Al NMR spectra of sols which varied in appearance from being very milky to completely transparent. No changes were observed in the 27Al spectra of sols which had been aged. The adddition of sufficient quantities of acid or base to gel the sol precipitated dramatic changes in the Al spectra. Aluminum-27 NMR was found to be a highly useful tool for probing the sol-gel transformation of this system.

Benzalpiperitone (I) has been dehydrogenated to 3-hydroxy-4-isopropylstilbene (II), which on ozonolysis gave rise to 3-hydroxy-4-isopropylbenzaldehyde (IV), which is unlikely to be identical with rheosmin. This substance appears on the basis of its properties and possible biosynthesis to be 1-(p-hydroxypheny1)butan-3-one (V).