Methyl ethers physicochemical properties

These have a partial common structure, i.e. enolyzed a-diketone and a-hydrogen to the enollzable carbonyl is substituted by a methyl group. For a characteristic sugary aroma, the presence of enol-hydrogen was essential, because the acetyl ester or methyl ether of sotolon showed no characteristic aroma. The extraordinarily low threshold value of sotolon may be due to its coexistence with hydrophilic and hydrophobic (alkyl-substituted lactone) partial structures in one molecule. The lower threshold value of the ethyl-substituted homolog (II) than that of sotolon may also be explained from the balance of these opposite physicochemical properties. 

The physicochemical properties of alkylated polysaccharides have received some attention, and details of the structures and conformations of 0-methylcelluloses, and their interaction in micelle junctions, have been included in a thorough discussion of polysaccharide gels and networks. Information on the polydispersity of samples of partially methylated cellulose may be obtained from column fractionation and by fractional precipitation from a solvent-nonsolvent system, but, for a more complete characterization of polydispersity, fractionation with a series of solvent-nonsolvent systems is necessary. The solubility, in water, of polysaccharides that are mainly methylated may be considerably improved by introduction of a few suitable ionizing groups, for example, by reaction with monochloroacetic acid to introduce carboxymethyl ether groups. The general sorption and diflFusion features of hydrocarbons and other... 

Both indoles were obtained as the methyl ethers. The chromophoric and physicochemical properties of 5,6-dimethoxyindole 13 and of 5,6-dimethoxyindole-2-carboxylic acid 23 (R = H) thus obtained were reported. As an extension of Raper s observations, Burton (32JCS546) reported the formation of the A-methyl indole 3 by oxidation of 3,4-dihydroxyphenylethylmethylamine with Ag20 and a simple synthesis of 5,6-dimethoxy-l-methylindole. 

PHYSICOCHEMICAL PROPERTIES OF METHYL ETHYL ETHER AND ITS MIXTURES WITH DIETHYL ETHER. 

SOME PHYSICOCHEMICAL PROPERTIES OF ETHYL METHYL ETHER AND ITS MIXTURES WITH DIETHYL ETHER. //ENGLISH TRANSLATION OF ZH. FIZ. KHIM. 41 /I/ 204,19677/... 

Laccaic acids have two or three carboxyl groups, five or six hydroxyl groups, and/or one amino group, and are freely soluble in water, but only shghtly soluble in organic solvents such as chloroform and ethyl acetate. Based on these physicochemical properties of laccaic acids, we selected a two-phase solvent system composed of tert-hutyl methyl ether/n-butanol/acetonitrile/water, which has been frequently used as the solvent system for the separation of hydrophihc... 

Flavonoids are characterized by having an aromatic ring with different degrees of substitution, including functional derivatives such as esters, methyl ethers, and glycosides. These structural characteristics determine the general physicochemical properties of these compounds. 

Polypyrrole colloids can be easily synthesised via dispersion polymerization using a wide range of commercial water-soluble nonionic polymers such as methylcel-lulose [21], poly(vinyl alcohol) [22,23], poly(N-vinyl pyrrolidone) [14,20-22], poly( vinyl methyl ether) [24,25], and poly(ethyIene oxide) [26-28]. Cationic [29,30] and anionic [31] polyelectrolytes have also been successfully used as polymeric stabilizers. The water-soluble polymer is physically adsorbed onto the surface of the growing polypyrrole particles, probably via a hydrogen bonding mechanism in many cases (see Fig. 17.1). The physicochemical properties of this steric stabilizer layer can have a profound influence on the colloi-... 

PA. McCarron, A.D. Woolfson, R.F. Donnely, G.P. Andrews, A. Zawislak, and J.H. Price, Influence of plasticizer type and storage conditions on properties of poly(methyl vinyl ether-co-maleic anhydride) bioadhesive films,/. Appl Polym. Sci., 91,1576-1589,2004. T.R.R. Singh, PA. McCarron, A.D. Woolfson, and R.F. Donnelly, Physicochemical characterization of poly(ethylene glycol) plasticized poly(methyl vinyl ether-co-maleic acid) films, /. Appl. Polym. Sci., 112, 2792-2799, 2009. 

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