Substituted phenols cyclohexanones from

Only one other synthesis from this review, the aldol self-condensation of cyclohexanone, followed by dehydrogenation of the initial products, is of preparative importance. It has even been used in the large scale industrial syntheses of 2,6-diphenyl-phenol (see 2.4). All the other routes mentioned in this account, are primarily of scientific interest and are not useful for larger scale preparative work. They ate, however, of interest insofar as they emphasize differences between the chemical properties of alkyl and aryl substituted phenols. 

In 1987, the successful startup of a new process was announced for the production of 10,000 tons/year of catechol and hydroquinone by the selective oxidation of phenol with H202 catalyzed by TS-1 at the Enichem plant in Ravenna, Italy (Notari, 1988). Soon thereafter, it was disclosed that another new process for the production of cyclohexanone oxime from cyclohexanone, H202, and NH3 with TS-1 as the catalyst was being developed (Roffia et al., 1990).The fact that a material with unusual catalytic properties had been obtained was then finally recognized, and the interest in titanium-containing catalysts spread rapidly in the scientific community, especially in industrial research laboratories. In the meantime, the synthesis method was studied and described in more detail and when all the necessary precautions were taken, TS-1 was reproduced in other laboratories, as were the highly selective catalytic reactions. The subsequent work confirmed that Ti v can assume the tetrahedral coordination necessary for isomorphous substitution of SiIV and added valuable information about the structure, properties and catalytic performance of the material. New reactions catalyzed by TS-1 have been discovered, and new synthetic methods... 

With 3,5-dimethoxybenzoyl chloride used in the monoacylation of cyclohexanone to produce finally the same (MeO ArC synthon, an alternative synthesis of cardol 8(Z)-monene was developed [138]. Fig( 4)-49, Persoonol dimethyl ether (5-[(Z)-undec-3-enyl]resorcinol dimethyl ether) was synthesised from 3,5-dimethoxybenzyl alcohol [149], This same reactant has been employed for a range of 5-substituted resorcinols although its application to unsaturated phenolic lipids was not discussed [228]. Acetylenic methods have proved valuable for deriving phenolic lipidic double bonds in the Z-configurations and with advances in boration methodology [229] the corresponding E-isomers are accessible. 

Many reports of selenium relate to its use as a source of double bonds. Continuing this theme, phenols are formed from cyclohexenones by phenyl-selenation (PhSeCl) and oxidative removal of the selenyl group (MCPBA). In their turn cyclohexenones have been prepared by a similar sequence. The interesting point here is that the double bond can be inserted at the less substituted conjugated position by base isomerization of the phenylselenocyclo-hexanone. For example, the phenylseleno-group in the cyclohexanone (283)... 

During the last period considerable attention has been given to Ti-silicalite, a zeolite derived from silicalite by partial substitution of framework Si with Ti (refs. 1-3). This zeolite exhibits very valuable catalytic properties for a variety of reactions of industrial interest, in particular for cyclohexanone ammoximation, phenol hydroxilation and olefins epoxidation (refs. 4, 5). Despite that, the stability of Ti-silicalite, as well as fundamental aspects of its characteristics and catalytic behaviour, has not been studied. In this work sorption measurements of small (N ) and large (p- and m-xylene) probe molecules were performed to characterize the porous structure of Ti-silicalite, before and after various thermal treatments. The results, compared to those obtained by spectroscopic and diffractometric techniques, provided information on stability of both zeolite lattice and titanium inserted in the framework. 

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