Cellulosates, alkali metal Cellulose

Other possibilities are the reduction of nitro groups by applying the sample solutions to adsorbent layers containing zinc dust and then exposing to hydrochloric acid vapors [110] 3,5-Dinitrobenzoates and 2,4-dinitrophenylhydrazones can also be reduced in the same way on tin-containing silica gel phases [111] Cellulose layers are also suitable for such reactions [112] Seiler and Rothweiler have described a method of trans-salting the alkali metal sulfates to alkali metal acetates [113]... 

Alkali-zelle,/. (Elec.) alkaline cell alkali-metal (photo)cell. -zellstoff, m. alkali cellulose. Alkalizitat, /. alkalinity. 

Earthquakes provide the ultimate test of the storage of incompatible chemicals and are sometimes followed by fires in chemical stores. Very few causes of ignition are found alkali metals halogen oxysalts in conjunction with strong acids and sulphuric or nitric acid and cellulose (wood flooring). These usually then ignite vapours of flammable solvents. 

Calcium bisulphite is largely used in the manufacture of sulphite pulp, from which paper and viscose silk (see p. 264) may be produced. Wood chips or shavings are boiled with the bisulphite under pressure and so yield cellulose, which at the same time is bleached. The bisulphites of magnesium and the alkali metals are also sometimes used. 

Less attention has been paid to the reaction of cellulose with rubidium hydroxide and with cesium hydroxide. Heuser and Bartunek101 isolated adducts of rubidium hydroxide and of cesium hydroxide that had the general formula MOH 3 C Hi0Ot. Their studies showed that the concentration, in weight percent, of alkali metal hydroxide required for forming a stable adduct of the lowest alkali content increases with increase in the atomic weight of the metal Li < Na < K < Rb < Cs. However, on a molar basis, this relationship does not hold. No simple relationship exists between the size of cation and the concentration of hydroxide necessary for the formation of a stable adduct. 

Nicoll, Cox, and Conaway127 have critically reviewed the different methods generally employed for determining the alkali content in cellulose-alkali metal hydrqxidei adducts. 

Of the oxy-anions having halogens in the +3 valence state, only the chlorite ion appears to be stable the alkali-metal chlorites are of some importance as cellulose bleaches. The chlorite ion results (along with an equivalent amount of chlorate) when C102 is dissolved in basic solution, a reaction analogous to the well known basic hydrolysis of NO. It is interesting that chlorites may also result from the reduction of C102 by peroxide in alkaline media ... 

The swelling of cotton with an aqueous solution of sodium hydroxide is an important com mercial treatment. It is called mercerization after its discoverer, John Mercer, who took a patent on the process in 1850 [308]. Other alkali metal hydroxides, notably lithium hydroxide and potassium hydroxide, will also mercerize cotton, but normally sodium hydroxide is used. Mercerization is utilized to improve such properties as dye affinity, chemical reactivity, dimensional stability, tensile strength, luster, and smoothness of the cotton fabrics [309]. The treatment is normally applied either to yarn or to the fabric itself either in the slack state to obtain, for example, stretch products, or under tension to improve such properties as strength and luster. The interaction of alkali metal hydroxides and cellulose has been extensively reviewed. Earlier reviews can be traced from relatively recent ones [99,310,311]. 

Venn obtained very little levoglucosan from the pyrolysis of raw cotton, whereas washing with water increased the yield to 28 %, and further prepurification by treatment with dilute alkali and acid provided a yield of 38%. Holmes and Shaw found that a cotton fabric purified by scouring and bleaching provided more tar and less char on vacuum pyrolysis than the reference materials. A Russian patent" claims that the heat resistance of cellulose is greatly increased by lowering the content of alkali metals to 0.03 — 0.05%. 

Carboxymethyl cellulose and its alkali metal salts (CMC) Carboxyalkylated cellulose -C O CH2COOH -c 0 C Substituted pyranose chain sequences... 

Cellulose acetate phthalate Esterified cellulose with about 20 and 35% acetate and phthalate groups, respectively Free acid form dissolves in organic solvents and only the alkali metal salts are water soluble Protective coating of tablets, insoluble in stomach but soluble in intestine fluids... 

U TLC cellulose Alkali metal solutions Fluorimetry, photo-1 ppm metry 277)... 

Reverse-Osmosis Separations of Alkali Metal Halides in Methanol Solutions Using Cellulose Acetate Membranes... 

The physicochemical criteria approach to reverse osmosis separations Involving the surface excess free energy of solvation for ionized and nonlonized solutes has been demonstrated by this work to include nonaqueous solutions. The parameters and correlations presented in this work permit the prediction of reverse osmosis separations and permeation rates for different alkali metal halides for cellulose acetate OEastman E-398) membranes of different surface porosities from only a single set of experimental data for a sodium chloride-methanol reference feed solution system. 

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