Cellulose acetone from

A great deal of work has been done on the effect of aqueous alkali on cellulose, from the viewpoint of the pulping industry (e.g., 16-28.48-59). The minor organic volatile products observed here at similar temperature to those used in Kraft pulping (150-180°C) eventually lead to colored product formation, which is of concern to the paper industry. The formation of acetone from cellulose has long been known. Generally, most interest has been shown in the nature of the residual cellulose after alkali treatment, not in the nature of the volatiles. From the viewpoint of determining the chemistry of oil formation from cellulose, the intermediate volatile products are all-important and the residual cellulose is of little interest. 

Cellulose acetate [9004-35-7], prepared by reaction of cellulose with acetic anhydride, acetic acid, and sulfuric acid, is spun into acetate rayon fibers by dissolving it in acetone and spinning the solution into a column of warm air that evaporates the acetone. Cellulose acetate is also shaped into a variety of plastic products, and its solutions are used as coating dopes. Cellulose acetate butyrate [9004-36-8], made from cellulose, acetic anhydride, and butyric anhydride in the presence of sulfuric acid, is a shock-resistant plastic. 

Cellulose acetate [9004-35-7] is the most important organic ester because of its broad appHcation in fibers and plastics it is prepared in multi-ton quantities with degrees of substitution (DS) ranging from that of hydrolyzed, water-soluble monoacetates to those of fully substituted triacetate (Table 1). Soluble cellulose acetate was first prepared in 1865 by heating cotton and acetic anhydride at 180°C (1). Using sulfuric acid as a catalyst permitted preparation at lower temperatures (2), and later, partial hydrolysis of the triacetate gave an acetone-soluble cellulose acetate (3). The solubiUty of partially hydrolyzed (secondary) cellulose acetate in less expensive and less toxic solvents such as acetone aided substantially in its subsequent commercial development. 

Production of cellulose esters from aromatic acids has not been commercialized because of unfavorable economics. These esters are usually prepared from highly reactive regenerated cellulose, and their physical properties do not differ markedly from cellulose esters prepared from the more readily available aHphatic acids. Benzoate esters have been prepared from regenerated cellulose with benzoyl chloride in pyridine—nitrobenzene (27) or benzene (28). These benzoate esters are soluble in common organic solvents such as acetone or chloroform. Benzoate esters, as well as the nitrochloro-, and methoxy-substituted benzoates, have been prepared from cellulose with the appropriate aromatic acid and chloroacetic anhydride as the impelling agent and magnesium perchlorate as the catalyst (29). 

A considerable number of systems have been used to separate chlorophylls on thin layers [30,31]. The most readily applicable layers are prepared from cellulose, silica, or sucrose and use hydrocarbon carriers with a polar modifier, usually acetone, in the developing solvent. However, silica layers cause a level of decomposition that is unacceptable for preparative work. Sucrose layers offer no particular advantages in separation and are neither commercially available nor recommended. 

A process for the production of cellulose acetate fiber produces a waste stream containing mainly air but with a small quantity of acetone vapor. The flowrate of air is 300 kmol h-1 and that of acetone is 4.5 kmolh-1. It is proposed to recover the acetone from the air by absorption into water followed by distillation of the acetone-water mixture. The absorber requires a flow of water 2.8 times that of the air. 

Acetone-soluble cellulose acetate is prepared by deacetylating cellulose triacetate. The product formed directly is unsatisfactory. Thus the distribution of free hydroxyls and acetate groupings is of primary importance. Cramer and Purves118(b) studied the distribution by tosylation and found that the acetyl removal from primary and secondary hydroxyl groups occurs at approximately the same rate, but that the number of... 

The list of pyrolysis products of cottonwood shown in Table VII (llj reflects the summation of the pyrolysis products of its three major components. The higher yields of acetone, propenal, methanol, acetic acid, CO, water and char from cottonwood, as compared to those obtained from cellulose and xylan, are likely attributed to lignin pyrolysis. Other results are similar to those obtained from the pyrolysis of cell-wall polysaccharides. This further verifies that there is no significant interaction among the three major components during the thermal degradation of wood. 

Fig. 8. Successive differential absorptions of acetone in cellulose nitrate at 25° C. Taken from Kishimoto, Fc/jita, Odani, Kurata and Tamura (1960)...

A brass (Cu-Zn) bar, wound with molybdenum wire, was plated with copper metal. The specimen was annealed in a series of steps, in which the movements of the molybdenum wires were recorded. The inert markers had moved from the interface towards the brass end of the specimen, which contained the fastest diffuser - zinc. This is now called the Kirkendall effect. A similar marker experiment had actually been performed by Hartley a year earlier while studying the diffusion of acetone in cellulose acetate (Hartley, 1946), but most metallurgists were not familiar with this work (Darken and Gurry, 1953). 

It should be noted that it is not only preparations of mixed polysaccharides which differ from cellulose in solubility, but also esters (acetates, nitrates) do not dissolve com Jetely m solvents of the corresponding cellulose esters. Thus, the nitrate of mixed polysaccharide(III), which contains 42 mol.-% of altrose, dissolves in acetone to 68%, and the triacetate dissolves in methylene chloride to 65 %. 

Acetate rayon is cellulose (from any source) in which about two of the hydroxyl groups in each unit have been acetylated. This renders the polymer soluble in acetone from which it can be spun into fiber. The smaller number of hydroxyl groups in acetate rayon compared to cotton makes direct dyeing of rayon more difficult than of cotton. 

V , the polymer-rich phase or the polymer-lean phase separates iRltially from the solution. If v Is smaller than the critical solution concentration, v, the p lymer-rlch phase separates as a small particle, whose slzf, defined by Its radius S., may be almost equal to or slightly larger than the critical radius, S, of the phase separation. Hereafter we call this particle the primary particle" (see Figure 2). As shown In a later section, primary particles have diameters, 2S, of around 20 to 30 nm In the cases of cellulose cuprammonlum soTutlon/acetone and cellulose acetate/ acetone systems. These particles grow Into secondary particles with radii of S.,... 

Diacetate fibres can be dissolved out by two treatments with acetone and triacetate fibres by three treatments with dichloromethane, in each case for 10 min at room temperature. In this way they can be separated from cellulose, wool, silk, polyester or acrylic fibres, which then remain as a residue. 

Figure 2 The pressure dependency of various penetrant-polymer systems (a) 30°C, I /polyethylene, (b) 20°C propane/polyethylene, (c) 35°C, carbon dioxide/ polycarbonate, (d) 40°C, acetone/ ethyl cellulose. (Reprinted with permission from ref. 15. Copyright 1987 John Wiley and Sons.)...

As the mobile phase flows through the fibres of the paper the cellulose will tend to adsorb more water from it. The result is that the moving solvent tends to become denuded of water as it advances, and its composition is not constant along the sheet (Figure 3.16). Sometimes there is a definite boundary where the solvent composition changes, for example, in some inorganic separations where acetone-water-hydrochloric acid mixtures are used as the solvent there is a dry solvent front, and, some instance behind it, a wet solvent front. The forward area consists of acetone from which the water has been removed, and the area behind the wet solvent front consists of aqueous acetone, and therefore contains all the acid. 

For example, 1,4-addition of the acetone carbanion to acrolein would be a facile reaction under the reaction conditions used for cellulose liquefaction (both of these intermediates are formed from cellulose). The product, 5-ketohexanal, could cyclize to 3-hydroxycyclohexanone, which would then dehydrate and dehydrogenate to phenol and related aromatic products. This route to an observed product (phenol) is still speculative, but we have shown the more direct route to phenol from cyclohexanone does not occur under the... 

Another class, the nitro-celluloses, are formed from cellulose, C 6 H 10 O 5, which forms the groundwork of all vegetable tissues. Cellulose has some of the properties of the alcohols, and forms ethereal salts when treated with nitric and sulphuric acids. The hexa-nitrate, or gun-cotton, has the formula, C 12 H 14 0 4 (0N0 2 ) 6 and collodion-cotton, pyroxylin, c., form the lower nitrates, i.e., the tetra- and penta-nitrates. These last are soluble in various solvents, such as ether-alcohol and nitro-glycerine, in which the hexa-nitrate is insoluble. They all dissolve, however, in acetone and acetic ether. 

Cellulose acetate is the most important ester produced from cellulose however, its use in adhesives is limited. Both the triacetate (DS greater than 2.75) and secondary acetate (DS of 2.4-2.6) are used industrially in plastics and textiles. The triacetate is soluble in mixtures of organic solvents, and the secondary acetate is soluble in acetone. Cellulose acetate is more heat resistant than cellulose nitrate but is less water resistant and tends to become brittle with age. 

The nanoyarn can be produced also from cellulose derivatives such as methyl-cellulose, ethylcellulose, nitrate cellulose, acetate cellulose, acetate-butyrate cellulose, etc. When, for instance, the nanoyam of acetate cellulose is produced, the initial polymer is dissolved in acetic acid, acetone, or ethylacetate (Stylianopoulos et al., 2012 Vargas, 2010). 

Figure 3.90 are presented the experimental values of UCST and LCST with thc-oretical values for the systems cellulose 3,0-acetatc (CTA) + acetone and cellulose 2,8-acetate (CDA(2,8)) + acetone (Cowie et al., 1971). The authors calculated 7 from the thermal expansion coefficient of acetone and from F.qiiations 28 and 26. The figure demonstrates qualitative agreement between theory and experiment, after the axes for the theoretical and experimental curves T are shifted by 169° relative to each other. 

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