CONTENTS Potassium Acetate

As previously discussed, solvents that dissolve cellulose by derivatization may be employed for further functionahzation, e.g., esterification. Thus, cellulose has been dissolved in paraformaldehyde/DMSO and esterified, e.g., by acetic, butyric, and phthalic anhydride, as well as by unsaturated methacrylic and maleic anhydride, in the presence of pyridine, or an acetate catalyst. DS values from 0.2 to 2.0 were obtained, being higher, 2.5 for cellulose acetate. H and NMR spectroscopy have indicated that the hydroxyl group of the methy-lol chains are preferably esterified with the anhydrides. Treatment of celliflose with this solvent system, at 90 °C, with methylene diacetate or ethylene diacetate, in the presence of potassium acetate, led to cellulose acetate with a DS of 1.5. Interestingly, the reaction with acetyl chloride or activated acid is less convenient DMAc or DMF can be substituted for DMSO [215-219]. In another set of experiments, polymer with high o -celliflose content was esterified with trimethylacetic anhydride, 1,2,4-benzenetricarboylic anhydride, trimellitic anhydride, phthalic anhydride, and a pyridine catalyst. The esters were isolated after 8h of reaction at 80-100°C, or Ih at room temperature (trimellitic anhydride). These are versatile compounds with interesting elastomeric and thermoplastic properties, and can be cast as films and membranes [220]. 

During the distillation of the azeotropic mixture the condensate (toluene) is sampled to determine moisture content. When the analysis is positive (absence of moisture by CUSO4), the sample is additionally analysed by the gasometric technique if the moisture content in toluene is not more than 0.02%, the dehydration of potassium acetate is considered complete. To account for the amount of dehydrated potassium acetate, the quantity of water poured off from collector 7 is measured by the difference of the weights of the loaded potassium acetate and the separated water one determines the precise amount of anhydrous salt. Toluene from collector 7 (after a thorough separation and its weighing) is poured into collector 10, and then sent to regeneration and returned into the production process. 

An estimate 440,000 metric tons (485,000 short tons) of potassium hydroxide were used in the United States in 2005. About 53 percent of that amount was used in the production of other potassium compounds, especially potassium carbonate (28 percent), potassium acetate, potassium cyanide, potassium permanganate, and potassium citrate. About 10 percent of all caustic potash was used in the manufacture of potassium soaps and detergents. Most soaps and detergents are made of sodium hydroxide. But potassium hydroxide can be substituted for sodium hydroxide to obtain soaps and detergents with special properties. Liquid soaps and soaps that will lather in salt water or water with a high mineral content are examples of such specialized potassium soaps. 

The adiabatic compressibilities of molten alkali metal acetate hydrates were measured at 60 °C for NaCH3C02 3H20 this practically coincides with its melting point Ks = 0.250 GPa Minima in xs as a function of the water content were found near this composition also for lithium and potassium acetate hydrates, with Ks slightly decreasing in the sequence Li > Na > K for the alkali metal cations [81]. All these values of the compressibilities are commensurate with those of the anhydrous molten salts in Tables 3.15 and 3.16. 

Saccharic acid. Use the filtrate A) from the above oxidation of lactose or, alternatively, employ the product obtained by evaporating 10 g. of glucose with 100 ml. of nitric acid, sp. gr. 1 15, until a syrupy residue remains and then dissolving in 30 ml. of water. Exactly neutralise at the boiling point with a concentrated solution of potassium carbonate, acidify with acetic acid, and concentrate again to a thick syrup. Upon the addition of 50 per cent, acetic acid, acid potassium saccharate sepa rates out. Filter at the pump and recrystaUise from a small quantity of hot water to remove the attendant oxahc acid. It is necessary to isolate the saccharic acid as the acid potassium salt since the acid is very soluble in water. The purity may be confirmed by conversion into the silver salt (Section 111,103) and determination of the silver content by ignition. 

The crude ketal from the Birch reduction is dissolved in a mixture of 700 ml ethyl acetate, 1260 ml absolute ethanol and 31.5 ml water. To this solution is added 198 ml of 0.01 Mp-toluenesulfonic acid in absolute ethanol. (Methanol cannot be substituted for the ethanol nor can denatured ethanol containing methanol be used. In the presence of methanol, the diethyl ketal forms the mixed methyl ethyl ketal at C-17 and this mixed ketal hydrolyzes at a much slower rate than does the diethyl ketal.) The mixture is stirred at room temperature under nitrogen for 10 min and 56 ml of 10% potassium bicarbonate solution is added to neutralize the toluenesulfonic acid. The organic solvents are removed in a rotary vacuum evaporator and water is added as the organic solvents distill. When all of the organic solvents have been distilled, the granular precipitate of 1,4-dihydroestrone 3- methyl ether is collected on a filter and washed well with cold water. The solid is sucked dry and is dissolved in 800 ml of methyl ethyl ketone. To this solution is added 1600 ml of 1 1 methanol-water mixture and the resulting mixture is cooled in an ice bath for 1 hr. The solid is collected, rinsed with cold methanol-water (1 1), air-dried, and finally dried in a vacuum oven at 60° yield, 71.5 g (81 % based on estrone methyl ether actually carried into the Birch reduction as the ketal) mp 139-141°, reported mp 141-141.5°. The material has an enol ether assay of 99%, a residual aromatics content of 0.6% and a 19-norandrost-5(10)-ene-3,17-dione content of 0.5% (from hydrolysis of the 3-enol ether). It contains less than 0.1 % of 17-ol and only a trace of ketal formed by addition of ethanol to the 3-enol ether. 

Thus, a polyester sample (1-3 g, exactly weighed) is dissolved in 25 mL of a titrated solution of acetic anhydride in dry pyridine (10% mass). The solution is heated to reflux for 1 h. After cooling, 50 mL pyridine and 10 mL water are added. The excess acetic acid present in the resulting solution is titrated by aqueous potassium hydroxide (0.5 mol/L) using a potentiometric titrator. The determination must be carried out in duplicate and a blank titration must be performed under the same conditions. The mass of polyester and the concentration of reactants should be adjusted to ensure that at least a fourfold excess of acetic anhydride is used. The final result (OH content) is expressed in mmol OH/g polyester or as the hydroxyl number, defined as the number of milligrams of KOH required to neutralize the acetic acid consumed per gram of polyester. [Hydroxyl number = (number of mmol OH/g polyester) x 56.106.]... 

A 2.000-g soil sample was analyzed for potassium content by extracting the potassium using 10.00 mL of aqueous ammonium acetate solution. Following the extraction, the soil was filtered and rinsed. The filtrate with rinsings was diluted to exactly 50.00 mL. Then 1.00 mL of this solution was diluted to 25.00 mL, and this dilution was tested with an instrument. The concentration in this 25.00 mL was found to be 3.18 ppm. What is the concentration of the potassium in the soil in parts per million ... 

The substance is burned on a platinum catalyst in a stream of oxygen and the iodine liberated is oxidised to iodic acid by bromine in acetic acid. After excess bromine has been removed with formic acid, potassium iodide is added to the solution, and the iodine liberated is titrated with thiosulphate. Since the amount of iodine titrated is six times the iodine content of the substance the method yields very accurate results. 

The purity of the hypochlorite may be determined by iodo-metric titration. This titration is run conveniently by weighing out a small portion of the hypochlorite (<0.5 g.) in a 4-ml. vial and then dropping the vial and its contents into an iodine flask containing 20 ml. of glacial acetic acid, 10 ml. of water, and 3 g. of potassium iodide. The titration is then conducted in the usual fashion. 

Active oxygen content is determined iodometrically 3 In an iodine flask, an accurately weighed sample (0.1-0.3 g.) is dissolved in 20 ml. of an acetic acid-chloroform solution (3 2 by volume), and 2 ml. of saturated aqueous potassium iodide solution is added. The flask is immediately flushed with nitrogen, stoppered, and allowed to stand at room temperature for 15 minutes. Fifty milliliters of water is then added with good mixing, and the liberated iodine is titrated with 0.1 A sodium thiosulfate, employing starch as indicator. A blank titration, which usually does not exceed 0.2 ml., is also run. One milliliter of 0.1 N sodium thiosulfate is equivalent to 0.00821 g. of tetralin hydroperoxide. 

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