Potassium hydroxide solutions viscosity

To a 250 ml flask equipped with a stirrer, a thermometer, a water condenser and Dean-Stark trap was added 11.42 g of 4.4 -isopropylidenediphenol (0.05 moles), 13.1 g of a 42.8% potassium hydroxide solution (0.1 mole KOH), 50 ml of dimethyl sulfoxide and 6 ml of benzene. The reaction mixture was kept under an atmosphere of nitrogen and the water was azeotroped oft over a 3 to 4 hours period (130—135° C). At the end of this time the reaction mixture consisted of the potassium salt of the biphenol and was essentially anhydrous. After cooling the mixture there was added 14.35 g (0.05 moles) of 4.4 -dichlorodiphenyl sulfone and 40 ml of anhydrous dimethylsulfoxide. The reaction mixture was maintained, under a nitrogen atmosphere, between 130 and 140° C with stirring for 4 to 5 hours. The viscous orange solution was then poured into 300 ml of water in a Waring Blendor and the polymer separated by filtration and dried at 110° for 16 hours. A yield of 22.2 g (100%) of polymer with a reduced viscosity in chloroform (0.2 g per 100 ml at 25°) of 0.59 was obtained. 

Apparently, there is no influence of oxygen during the preparation of the fractions in the chloral hydrate procedure, as judged from the values of intrinsic viscosity of the experiments given in Table III. Furthermore, it may be noted that the amylopectin fractions obtained by this method are insoluble in hot water (as well as in cold 1.0 AT potassium hydroxide solution). ... 

It depends upon the purpose for which the viscosity is needed. In our own laboratories, where we are concerned primarily with a fundamental characterization of the gum, we measure viscosity in IN potassium hydroxide solution with g uar concentrations varying from 0.5 to 1%. From such measurements we can also calculate limiting intrinsic viscosity. 

The polymer solution is diluted to a workable viscosity with benzene and extracted three times with 5% aqueous potassium hydroxide solution, so that a sample of the next to the last aqueous extract gives no precipitate upon acidification. The benzene solution is then repeatedly washed with deionized water until the washings have the same (near neutral) pH as the fresh, deionized water being used. The benzene solution is carefully separated and filtered into a tared beaker. The solvent and monomer is allowed to evaporate at room temperature. The residue is dried to constant weight for 3 days at 60°C and 0.3 mm Hg. 

Other physical phenomena that may be associated, at least partially, with complex formation are the effect of a salt on the viscosity of aqueous solutions of a sugar and the effect of carbohydrates on the electrical conductivity of aqueous solutions of electrolytes. Measurements have been made of the increase in viscosity of aqueous sucrose solutions caused by the presence of potassium acetate, potassium chloride, potassium oxalate, and the potassium and calcium salt of 5-oxo-2-pyrrolidinecarboxylic acid.81 Potassium acetate has a greater effect than potassium chloride, and calcium ion is more effective than potassium ion. Conductivities of 0.01-0.05 N aqueous solutions of potassium chloride, sodium chloride, potassium sulfate, sodium sulfate, sodium carbonate, potassium bicarbonate, potassium hydroxide, and sodium hydroxide, ammonium hydroxide, and calcium sulfate, in both the presence and absence of sucrose, have been determined by Selix.88 At a sucrose concentration of 15° Brix (15.9 g. of sucrose/100 ml. of solution), an increase of 1° Brix in sucrose causes a 4% decrease in conductivity. Landt and Bodea88 studied dilute aqueous solutions of potassium chloride, sodium chloride, barium chloride, and tetra-... 

The polymerisation is carried out in a reactor with an agitator and a water vapour jacket in the presence of a catalyst (10-12% alcohol solution of potassium hydroxide) at 20+5 °C. The polymerisation is continued until the product attains a certain viscosity after that, the reactor is loaded with a required amount of dimethyldichlorosilane to break the chain, with an addition of toluene to dilute the varnish. The polymer is treated with dimethyldichlorosilane for 3-5 hours at agitation the end of the stage is monitored by the universal indicator. The varnish is filtered to eliminate mechanical impurities and potassium chloride and sent to repeated toluene distillation, which is continued until the varnish attains the necessary viscosity and polymer content. 

The course of the reaction can be followed by (1) the drop in acid content, since the -COOH group disappears for every ester link formed, (2) the rise in viscosity and also less reliably by (3) the volume of water produced. The acid content is measured by titration of resin solution with alcoholic alkali solution and the acid value (AV) or acid number (AN) of the resin is the number of milligrams of potassium hydroxide required to neutralize 1 g of solid resin. AV values of commercial alkyds are usually between 5 and 30. Water evolution is never sensitive enough to monitor the reaction properly, and the first two tests are those normally carried out together. 

Quality control in the manufacture of alkyd resins involves appropriate rapid tests to determine the acid number, viscosity of solutions of known concentrations in mineral spirits or xylene (Gardner-Holdt viscosity tubes used for comparison), color (Gardner 1933 Color Standards), and cure time. A target range 2-5 units above the acid number units of gelation is desirable. Most manufactured alkyd resins have an acid value (number of mg of potassium hydroxide required toneutralize 1 gm of resin) of less than 15. 

Preparation of II. Aqueous potassium ferricyanide (0.329 g, 0.001 m) was added dropwise over a 27 minute period to a vigorously stirred mixture of a solution of 3,4-dibromo-2,6-dimethyl-phenol (I) (2.80 g, 0.01 m) in 150 ml benzene and 150 ml aq. 2% solution of potassium hydroxide at 25 under a nitrogen atmosphere. After 170 minutes, the benzene layer was separated eind washed with 10% hydrochloric acid and then with water. The solution was added dropwise to 500 ml methanol. The polymer was filtered off, washed with methanol, and dried 20 hours at 25 and 12 Torr. Weight 2.0 g (100% yield). Intrinsic viscosity ... 

Neutral salts, such as sodium chloride, potassium chloride, magnesium chloride, calcium chloride, and thorium nitrate, have only a small influence on the viscosity of aqueous solutions of the gum a slight increase can be detected. It is noteworthy that sodium hydroxide changes the viscosity to a high degree, as shown in Figure 4. 

Addition of sodium, potassium, calcium, ammonium, etc., bases to aqueous solutions of Gantrez AN resins leads to two viscosity peaks, corresponding to 1 and 2 mole equivalents of base. The interpolymers are precipitated by Ca ions and other heavy, polyvalent metal cations, beyond 0.7 mole equivalents. With ammonium hydroxide, peaks tend to be observed at about 1 and 3 mole equivalents of base. Ionic interactions in aqueous solutions of Gantrez AN polyelectrolytes and polycarboxylates, electrophoretic mobility and viscosity of copolymer salts, counterion binding properties, etc., have received substantial <659,672.700-702,1100) polyelectrolyte salt sol-... 

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