Acetic acid sodium salt hydrolysis

The rate of hydrolysis of cellulose acetate can be monitored by removing samples at intervals during hydrolysis and determining the solubiUty of the hydrolyzed acetate. When the desired DS is reached, the hydrolysis is stopped by neutralizing the catalyst with magnesium, calcium, or sodium salts dissolved in aqueous acetic acid. 

Solution Process. With the exception of fibrous triacetate, practically all cellulose acetate is manufactured by a solution process using sulfuric acid catalyst with acetic anhydride in an acetic acid solvent. An excellent description of this process is given (85). In the process (Fig. 8), cellulose (ca 400 kg) is treated with ca 1200 kg acetic anhydride in 1600 kg acetic acid solvent and 28—40 kg sulfuric acid (7—10% based on cellulose) as catalyst. During the exothermic reaction, the temperature is controlled at 40—45°C to minimize cellulose degradation. After the reaction solution becomes clear and fiber-free and the desired viscosity has been achieved, sufficient aqueous acetic acid (60—70% acid) is added to destroy the excess anhydride and provide 10—15% free water for hydrolysis. At this point, the sulfuric acid catalyst may be partially neutralized with calcium, magnesium, or sodium salts for better control of product molecular weight. 

The sodium salt of aceto-coumaric acid on hydrolysis decomposes, yielding first an acid which loses water, forming coumarin, together with acetic acid-—... 

The hydrolysis of the sodium salt of a weak acid can be treated similarly. Thus for a solution of sodium acetate... 

The diacetylated ethane-1-hydrox-1,1-diphosphonic acid is prepared by dissolving the diphosphonic acid in acetic acid and adding acetic anhydride [114]. The sodium salt can be directly converted to the free acid form by passing it through an hydrogen cation exchanger. The bicyclic dimer is prepared by basic hydrolysis of diacetylated cyclic dimer, as shown in Eq. (70) ... 

Indole (I) condenses with formaldehyde and dimethylamine in the presence of acetic acid (Mannioh reaction see Section VI,20) largely in the 3-position to give 3-dimethylaminomethylindole or gramine (II). The latter reacts In hot aqueous ethanol with sodium cyanide to give the nitrile (III) upon boiling the reaction mixture, the nitrile undergoes hydrolysis to yield 3-indoleacet-amide (IV), part of which is further hydrolysed to 3-indoleacetic acid (V, as sodium salt). The product is a readily separable mixture of 20 per cent, of (IV) and 80 per cent, of (V). 

H. N. Stokes prepared salts of triimidotetraphosphoric add, HN PO(OH).NH. PO(OH)2 2, by the hydrolysis of salts of pentametaphosphimic acid—e.g. a hot acetic acid soln. of sodium pentametaphosphate furnishes sodium triimidotetra-phosphate, NH PO(OH).NH.PO(ONa)2 2 and the addition of silver nitrate to the soln. furnishes the silver triimidotetraphosphate, HN PO(OH).NH.PO(OAg)2 2. The acid is so unstable that it cannot be made by heating tetrametaphosphimate as might have been anticipated by the formation of diimidotriphosphoric acid by the action of heat on trimetaphosphimic acid. 

While the hydrolysis of triphosphonitrilic chloride with sodium acetate furnishes trimetaphosphimic acid and the hydrolysis of tetraphosphonitrilic chloride with water furnishes tetrametaphosphimic acid, the hydrolysis of pentaphosphonitrilic chloride, P5N5C1i0, with sodium hydroxide in ethereal soln. furnishes sodium pentametaphosphimic acid, PsNsHloO10, or rather the alkali pentameta-phosphimate—sufficient alkali must be present to maintain the alkalinity of the soln. The sodium salts are amorphous, and are precipitated in a gelatinous form by the addition of alcohol to the alkaline soln., or to the soln. neutralized with acetic... 

One often needs to calculate the pH of a salt solution that comes from a weak acid and a strong base, such as sodium acetate. For this salt, Kb = 10 u/(2 x 10-5) = 5 x 10-10, where 2 x 10-5 is the Ka of acetic add. Because sodium acetate solutions are alkaline because of the hydrolysis phenomenon,... 

The carbonate salts investigated by Siegfried and Howwjanz were decomposed instantly by dilute acetic acid, whereas the moderate stability of the 0-(sodium thiolthiocarbonyl) derivatives toward this reagent has been a valuable aid to their purification. In mineral acids, however, the 0-(metal thiolthiocarbonyl) compounds are also rapidly attacked, with regeneration of the carbohydrate, a property utilized in the cellulose Viscose process. The 0-(sodium thiocarbonyl) derivative of cellulose is less resistant to acid hydrolysis than its thiolthiocarbonyl analog. 

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