Esterification 660 REACTION INDEX

Our results on esterification over zeolites HP, HZSM-5, HY, DHY and y-Al203 clearly show that zeolite HP is the most suitable catalyst containing the required type of acidity suitable for esterification reaction and this is also confirmed by cyclohexanol dehydration activity (99.9% conversion) an acidity index reaction. 

Finally, the catalytic activity of DMCs in esterification reactions can be readily combined with their catalytic activity in epoxide ring-opening polymerizations, as was reported by Suh et al. [35]. This study showed that the copolymerization of propylene oxide with cyclic acid anhydrides such as succinic, maleic, or phthalic anhydride, catalyzed by a Zn-Co-DMC, afforded polyester polyols characterized by a moderate molecular weight and narrow polydispersity index. 

The choice of which reactions to include is not an easy one. First there are the well known "Name Reactions", that have appeared in various monographs or in the old Merck index. Some of these are so obvious mechanistically to the modern organic chemistry practitioner that we have in fact omitted them for instance esterification of alcohols with acid chlorides - the Schotten-Baumann procedure. Others are so important and so well entrenched by name, like the Baeyer-Villiger ketone oxidation, that it is impossible to ignore them. In general we have kept older name reactions that are not obvious at first glance. 

We have dealt above with a pure case of doublet reaction and other reactions. It is only natural that there can be some quite reasonable deviations. The bonds requiring activation must come into contact with the catalyst. If, for instance, one part of the index of the doublet reaction does not require activation, it can react without coming into contact with the catalyst. Such a half-doublet scheme for esterification in solution was given by the author 37). Hence, the transition from heterogeneous to homogeneous catalytic reactions occurs, and in the extreme case in which both the bonds of the doublet group do not require activation for the reaction, to noncatalytic reactions. 

In some doublet reactions the same products may be obtained from the same reactants but in different ways. Such reactions were referred to as olistomeric and the structural conditions of their appearance were determined on the basis of the multiplet theory (348). Thus, theoretically two cases of bond fission can take place in esterification, HO—COR + H—OR and H—OCOR HO—R. The tracer method shows that the first case is realized as a rule. The half-doublet scheme expresses such experiments. The doublet indexes for the reactions in solutions disintegrate into such schemes see Balandin (37). A complete system of doublet reactions for C, H, N, 0, S, and Cl (without their isotopes) has been obtained by the author (345). It is much more detailed than Table VII and amounts to 1500 types. It was obtained by exhaustive variation of atoms and bonds in the index by means of a specially developed method based on matrix algebra and combinatorial analysis. The significance of the obtained classification for organic catalysis is similar to that of the complete system of forms in crystallography, which was derived from the groups of symmetry by Fedorov and covers all possible forms (349). 

ATRP has been also utilized for the synthesis of an AB4 miktoarm star copolymer, where A is a PNIPAM block and B is a PDEAEMA block [53], At first, a mono-amino terminated PNIPAM homopolymer was synthesized. Subsequently, an addition reaction on the amino group using glycidol was realized, followed by esterification with excess 2-bromoisobutyryl bromide. The end functionalized PNIPAM formed in this way could be used as a tetrafunctional macroinitiator for the polymerization of DEAEMA monomers via ATRP. The formation of pme AB4 miktoarm star copolymer was assumed by the authors based on results from size exclusion chromatography. However, the polydispersity index was quite high (Mw/Mn= 1.23), therefore, SEC alone could not unambiguously confirm the level of purity of the miktoarm stars. 

At the end of the transformation, acetic anhydride in excess is hydrolyzed in acetic acid, which is directly titrated in the reaction medium with a sodium hydroxide solution in the presence of phenolphthalein. The same operations are realized with a blank in which there is no hydroxylated derivative, all the other experimental conditions being the same as in the assay. The difference between both volumes added gives the number of moles of acetic acid used for the esterification. The in pyridine acetylation index is of great interest in the analysis of essential vegetable oils, fats, and numerous pharmaceutical compounds, including, for instance, the determinations of cetylic and benzylic alcohols. The propionyl index is based on the same principle, but all of the operations are performed in a nonaqueous medium. 

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