Sodium hydroxide solution, electric resistance

On the other hand, the electric resistance of the membrane before the reaction with phosphorous pentachloride and triethylamine was 1,1 - cm2 and l,0i2- cm2 respectively when measured in the environment of 3,5 N sodium chloride solution to its one side and 6.0 N sodium hydroxide solution to the other side, and in the environment of 3.5 N sodium chloride solution of pH 0,5, According to reflective infrared spectrum, the absorption bands observed were different between the surfaces reacted with phosphorous pentachloride and non-reacted. Namely the absorption band at 1680cm 1 corresponding to carboxyl groups was observed, and the absorption band at 1060cm l observed in the sulfonic acid type membrane disappeared on the surface which had been reacted with phosphorous pentachloride. 

Chemical Stability. The wire made from PPT(I) exhibited good chemical resistance. For example, there was no change in electrical resistance after the wire was submerged in 5% hydrochloric acid solution or gasoline at room temperature for 24 hours or was boiled in 40% sodium hydroxide solution, lubricating oil, benzene or ethyl alcohol for 24 hours. These properties are shown in Table V. 

Figure 4.1 Change in electrical resistance of perfluorocarbon sodium sulfonate membranes (Nafion ) and specific resistance of sodium hydroxide solution with concentration of sodium hydroxide.

Grayish-white metal hody-centered cubic crystalline structure density 19.3 g/cm3 melts at 3,422°C vaporizes at 5,555°C vapor pressure 1 torr at 3,990°C electrical resistivity 5.5 microhm-cm at 20°C modulus of elasticity about 50 to 57 x lO psi (single crystal) Poisson s ratio 0.17 magnetic sus-ceptibilty +59 x 10-6 thermal neutron absorption cross section 19.2 + 1.0 barns (2,200m/sec) velocity of sound, about 13,000 ft/sec insoluble in water practically insoluble in most acids and alkabes dissolves slowly in hot concentrated nitric acid dissolves in saturated aqueous solution of sodium chlorate and basic solution of potassium ferricyanide also solubibzed by fusion with sodium hydroxide or sodium carbonate in the presence of potassium nitrate followed by treatment with water... 

Derivation From tantalum potassium fluoride by heating in an electric furnace, by sodium reduction, or by fused salt electrolysis. The powdered metal is converted to a massive metal by sintering in a vacuum. Foot-long crystals can be grown by arc fusion. Corrosion resistance 99.5% pure tantalum is resistant to all concentrations of hot and cold sulfuric acid (except concentrated boding), hydrochloric acid, nitric and acetic acids, hot and cold dilute sodium hydroxide, all dilutions of hot and cold ammonium hydroxide, mine and seawaters, moist sul-furous atmospheres, aqueous solutions of chlorine. 

The properties of the membrane hydrolyzed with 10 % sodium hyroxide were measured, and a saturated sodium chloride solution was electrolyzed using this membrane. The results are given in Table I. For comparison, the sulfonyl chloride-type membrane was treated in n-butyl alcohol at 110 °C for 3 hours without introducing air. The treated membrane was subjected to hydrolysis treatment in a methanol solution containing 10 % of sodium hydroxide. Electric resistance of the membrane was 450 —cm, and the current efficiency could not be measured. 

The membrane which had a thin layer of sulfonyl chloride groups was treated by triethylamine at room temperature for 16 hours, washed with water and then heated at 170°C. Thereafter, the membrane was also immersed in the same mixed solution composed of water, dimethyl sulfoxide and potassium hydroxide as mentioned before. Electric resistance of the membrane was 1.5ft- cm2 when measured in the environment of 3.5 N sodium chloride solution to... 

The membrane having the sulfonyl chloride groups was treated by an aqueous n-butyl amine solution for 2 hours, washed with water, heated in air for 24 hours at 90°C and then dipped in 10% methanol solution of sodium hydroxide. The reflective infrared spectrum showed that absorption band ascribable to the sulfonyl chloride disappeared and new absorption bands appeared at 1620, 1680 and 3400 cm l, The electric resistance and the electrolysis results of both of the treated and untreated membranes are shown in Table II respectively. 

Permselectivity of counter-ions through the ion exchange membrane depends on the fixed ion concentration of the membrane (Chapter 2.3). Many attempts have been made to increase the fixed ion concentration of the membrane to increase the ion exchange capacity and to decrease the water content of the membrane, namely, to increase the fixed ion concentration without increasing the electrical resistance of the membrane. Figure 4.8 shows an example of the relationship between current efficiency to produce sodium hydroxide and the fixed ion concentration of the membrane for the electrolysis of sodium chloride solution.17 It is apparent that the current efficiency increases with increasing fixed ion concentration of the membrane. 

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