Ether anomaly

Fig. 8-9. Solvent strength and the ether anomaly in dilute solutions of ethyl ether in pentane. Adsorption on 3.8% H2O-AI..O3. Reprinted from the Journal of Chromatography 12) by permission of Elsevier Publishing Company.

Thus, 2-furfuryl vinyl ether 6a is extremely sensitive to cationic activation (16) because of its very pronounced nucleophilic character, but the polymerization is accompanied by some gel formation due to abundant alkylation of the furan rings pendant to the macromolecules. This structural anomaly is not encountered with the 5-methylated monomer 6b (16) precisely because electrophilic substitutions take place predominantly at C5 and are therefore impossible with this monomer. A similar difference of phenomenolo was observed with the 2-fiiryl oxiranes 4a and 4b (17). 

The safety and pharmacological profiles of hypromellose acetate succinate are similar to those of other ether and ester derivatives of cellulose.All nonclinical studies reported in the literature identify no target organs for toxicity by hypromellose acetate succinate. It has also been reported that hypromellose acetate succinate does not alter fertility in rats, does not produce any developmental anomalies in rats and rabbits, and does not alter perinatal and postnatal development in rats when assessed up to 2500mg/kg. ... 

Table I lists typical properties of a baker s dozen of these resins, produced by typical direct preparations, without extensive purification. Overall, the viscosities of these resins were quite low, particularly by comparison to the well known general purpose epoxy resins based on the diglycidyl ether of bisphenol A (DGEBA). The more shielded higher alkylsubstituted hydantoin rings favored lower viscosities. Some anomalies in these viscosities presumably reflected either a tendency of certain resins to crystallize, or the presence of some species of higher molecular weight, formed by reaction of the glycidyl group with a second hydantoin ring.

When the alkenyl component is an O-terf-butyldimethylsilyl (TBDMS) enol ether, another anomaly occurs independent of enol ether geometry, the anti product is favored (Scheme 6.8) [62]. With trimethylsilylpropargyl ethers, the anti selectivity is 95-98%, making this reaction an excellent route for the preparation of anti 1,2-diols. In these cases, transition structures similar to Figure 6.6c and d are operative, the dominant influence being mutual repulsion between the carbanion substituent, R, and the 0-silyl group. 

Moreover, mass law retardation was evident on the conversion of cis-[PtMe(MeOH)(PEt3)2] in methanol/ether mixtures. In a general comparison of previously performed isomerizations of cis-[PtRCl(PEt3)2], the authors concluded that methanol solvolysis followed by dissociation of the methanol competed with direct dissociation of the chloride, and that a geometry change of the 3-coordinate intermediate applied in each case. The exception was when R was mesityl, the bulk of this ligand presumably being responsible for the anomaly. Scheme 4 combines these conclusions. 

Concerning the polymer, the main problem is the difficulty to find suitable solvents for PACA characterization, especially for the determination of their MW. The strongly polar solvents (nitromethane, acetonitrile and DMF) dissolve the polymers from methyl, ethyl and w-butyl esters (PMCA, PECA, PBCA), but they are suspected to cause degradation. Ether-type solvents are supposed to be inert, thus suitable. THF is indicated only for PBCA, since PMCA is insoluble, and PECA of high MW in THF shows a high viscosity and GPC anomalies. 

The monograph by Aubert and Sivolobov presents data on 69 hydrocarbons, 10 alcohols, 2 ethers, graphite, and thiophen for the solid, liquid, and vapour states in the temperature range 90 to 1400 K. Methods for the calculation of vapour heat capacities are given and the principal types of heat capacity anomaly in the condensed phases are presented. Tables giving melting temperature, enthalpies of transition, and entropies are provided. 

In addition to information concerning chain transfer ability, the data in Table 4 indicated a relationship between conversion and the complexing ability of the particular crown ether utilized as phase transfer catalyst. In fact, when percent conversion was plotted vs the log of the binding constants (log K) of the respective crowns for potassium cation, an apparently linear correlation was obtained. On the basis of some simple assumptions and free radical addition polymerization theory, however, it may be deduced that conversion should correlate with K rather than log K (Equation 1). This anomaly was resolved by using inhibitor-free monomer (Table 5), whereupon a good correlation (R=0.948) between the variables was obtained. 

The alcohol employed in these experiments was commercial alcohol I wanted to know what pure alcohol would give, which is placed, as for its volatiUty, between the precedent and the pair benzine and dichloroethane however in the bottle, much of its c s burst colorless it is thus, under this point of view, between the pair above and the pair chloroform and ether, and thus constitutes a slight anomaly but 1 do not think that this one is enough to prevent me from claiming the influence of volatility generally. 

Benzene has been amido-alkylated by reaction with ArC6H4CHClNR COR and AICI3 (R and R are various alkyl and phenyl) to ArCHPhNR COR in fair to good yields.Anisole and phenetole have been alkylated with l-chloro-2,3-epoxy-5-methylhex-5-ene and AlCls. A dissertation on apparent anomalies in the Friedel-Crafts alkylation of 2,6-dimethylphenol and its alkyl ethers has been cited. 

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