Hydroxy compounds, with Cellulose

Magnesium compounds retard cellulose depolymerization by deactivating the transition metal catalysts. In alkaline media where hydroxy-acids or products of polysaccharide degradation are present, magnesium forms stable complexes with transition metals. The formation of iron-magnesium complexes in particular is supported by interactions approximating the coordination number of iron (6) and one half the coordination number (3). 

The rate of acetylation of 0-(hydrox3Tnethyl)cellulose (and other hydroxy compounds) by mixtures of carboxylic acids and their anhydrides has been found to increase greatly in the presence of trifluoroacetic acid. The acceleration is very much less with mono- and tri-chloroacetic acids, presumably because they form unsymmetrical anhydrides which are less effective acylating agents than acyl trifluoroacetates. The exceptional acylating power of the latter anhydrides is shown by their use in the synthesis of alkyl aryl ketones from polyalkylbenzenes, phenyl ethers, furan, and thiophene under mild conditions. The principle has been extended to include acids... 

Barnett acetylation method. Acetylation of hydroxy compounds such as cellulose with acid anhydrides in the presence of chlorine and sulfur dioxide. With cellulose, the process yields the diacetate below 65C and the triacetate above this temperature. 

P-HYDROXY- ETHYLDIMETHYLAMINE (108-01-0) Forms explosive mixture with air (flash point 105°F/41°C oc). An organic base. Violent reaction with oxidizers, acids. Ignites spontaneously with cellulose nitrate, and possibly other nitrogen compounds. Silver, cobalt, or chromium compounds may cause explosions. Contact with nitromethane forms a heat-, friction-, and shock-sensitive explosive. Incompatible with acrylates, aldehydes, alcohols, alkylene oxides, caprolactam solution, cresols, organic anhydrides, substituted allyls, epichlorohydrin, glycols, halogenated compounds, isocyanates, ketones, mercury, phenols, vinyl acetate. Attacks copper, zinc, and their alloys, galvanized steel. 

For the alumina layer it was concluded that the hydrogen-bonding associative effect is predominant and tends to mask the influence of the substituent effect except in the case of 2-substituted compounds, where a steric factor impedes the association. With cellulose the separation of the phenols is governed by their relative partition. The phenols, initially dissolved in the stationary phase, are removed by solvation of the phenolic hydroxy group by the mobile phase. In the case of 2-substituted compounds, solvation of the phenolic group is hindered and lower Rf values result. For cellulose... 

The kinetics of homogeneous reaction of several reactive dyes of the vinylsulphone type with methyl-a-D-glucoside (7.9), selected as a soluble model for cellulose, were studied in aqueous dioxan solution. The relative reactivities of the various hydroxy groups in the model compound were compared by n.m.r. spectroscopy and the reaction products were separated by a t.l.c. double-scanning method [38]. The only sites of reaction with the vinylsulphone system were the hydroxy groups located at the C4 and C6 positions [39,40]. 

Starch and cellulose, two polymeric carbohydrates with many OH groups, were first discussed in Section 5.1. Starch is used for short-term energy storage, and cellulose is the major structural compound in plant and bacterial cell walls. The many hydroxy groups allow for substantial... 

With cotton (cellulose), the direct dyes usually contain o-hydroxy- or aminoazo compounds, in which chelation assists in the production of hydrogen bonds between the dye and the cotton (1) ... 

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