Potassium hydroxide equivalent weight

Polyols are identified by their hydroxyl numbers. If the polyol is initiated using ethylene glycol, and the polyol can be identified as a diol, with a functionality of 2, the average molecular weight can be determined. Hydroxyl number is defined as the number of milliweights (or milligrams) of potassium hydroxide equivalent to the active functions (hydroxyl content) of 1 g of the compound or polymer. 

The industrial term potash can be very misleading. It can refer to potassium carbonate (K2CO3), potassium hydroxide (KOH), potassium chloride (KCl), potassium sulfate (K2SO4), potassium nitrate (KNO3), or collectively to all potassium salts and to the oxide K2O. More correctly KOH is called caustic potash and KCl is called muriate of potash. Production is recorded in weight equivalents of K2O since almost all potash is used as fertilizer and this industry quotes weight percentages of K2O in its trade. 

Treat 1 g (1 ml) of the amine with 4 molar equivalents of 10 per cent sodium or potassium hydroxide solution (say, 20 ml), and add 1.5 moles (or 3 g if the molecular weight is unknown) of benzenesulphonyl or toluene-p-sulphonyl chloride in small portions with constant shaking. To remove the excess of acid chloride, either shake vigorously or warm gently. Acidify with dilute hydrochloric acid and filter off the sulphonamide. Recrystallise it from ethanol or dilute ethanol. 

Specification sheets will often give the equivalent weight of the polyol in terms of the hydroxyl number ("OH" value). The hydroxyl number is defined as "the number of milligrams of potassium hydroxide (KOH) equivalent to the hydroxyl content of 1.0 grams of polyol." Manipulation of this definition gives the follow equation ... 

The only practical difference between potassium and sodium hydroxide, as far as photography is concerned, is that 10 parts by weight of sodium are the equivalent of 14 parts by weight of potassium. Also, potassium hydroxide is more soluble, meaning more will go into solution than sodium hydroxide. The limit of sodium hydroxide in water is 50% the limit for potassium hydroxide is somewhat higher. 

When equivalent weights of sodium and potassium hydroxide are mixed, and fused in absence of air, sodium monoxide is formed, hydrogen evolved, and potassium distils at a temperature of about 670° C. The metal can be condensed, and the process is claimed to be applicable to its manufacture.2... 

Crude oils may be up to 15% FFA, while refined oils will be <0.1%. Measurement of FFA is normally done by titration of an ether-ethanol solution of the fat with standardized aqueous sodium or potassium hydroxide, in the presence of phenolphthalein indicator (see ISO 660 1983). This method is very accurate, using the molecular weight of oleic acid (282) for all calculations. Accuracy is improved by using the average molecular mass of the fatty acids in the fat, calculated from the FA composition (e.g., for palm oil 256 is used, for palm kernel/coconut oil 200 is used). The results are expressed either as acid value the number of milligrams of potassium hydroxide required to neutralize 1 g of the fat, or, FFA% the percentage concentration of oleic acid equivalent to the free acids present. 

The syntheses of three new aromatic ionomers with equivalent weights of ca. 800, 600 and 400 have been carried out. Thus, 3,3(oxydi P phenylene)bis[2,4,5-triphenylcyclo-pentadienone] and 3,3 -(oxydi-p-phenylene)bis[2,5-diethoxy-carbonyl-4-phenylcyclopentadienone] were copolymerized with 4,4 -diethynyldiphenyl ether in molar ratios of 70 30 100, 60 40 100 and 40 60 100 to afford the corresponding alkoxy-carbonyl-substituted polyphenylene oxides, which were converted to the ionomers by treatment with potassium hydroxide. 

To a resin flask equipped with a thermometer, stirrer, and reflux condenser is added 1000 gm of octamethylcyclotetrasiloxane. The siloxane is heated to 165°C, and then 0.14gm of a potassium hydroxide-isopropanol complex (neutral equivalent = 193.5) is added to give a Si K ratio of 4470 1. In 25 min the stirrer begins to stall, and the polymer is now heated for 3y hr at 150 C to complete polymerization. The resulting polymer has an intrinsic viscosity of 1.5 dl/gm corresponding to a molecular weight of 804,600. 

The determination of the equivalent weight of an ester is valuable more particularly in cases where the acid component is difficult to isolate and characterize. The following method is suitable for esters which have been found to be hydrolysed fairly readily by alcoholic or aqueous alkali. Accurately weigh about 1 - 0 g of the ester into a clean 100 ml flask and add 20 ml of N alcoholic potassium hydroxide and 2 ml of water. Carry out a control experiment without the ester. Boil each solution imder reflux very gently for about 30 minutes. Wash down each condenser with about 10 ml of water and cool the flasks. Titrate the contents of each flask with N hydrochloric acid to phenolphthalein. 

In the second method. Stone et al. [84] copolymerized monomer 4-2 with TFS (Fig. 2.17) by emulsion polymerization in 21% isolated yield. The optimized ratio between TFS and the dimethyl phosphonate-substimted a,, -trifluorostyrene monomer in the copolymer 4-5 was 2.4 1. The molecular weights of the resulting copolymer were 38,100 and 105,900g/mol for and respectively. Homo-polymer 4-3 (membrane A) was hydrolyzed under acidic conditions (hydrochloric acid in dioxane, 100 °C, 20 h). The yield and the equivalent weight of acid functions were 95% and 130 g/mol, respectively. Copolymer 4-4 was hydrolyzed by the authors using two processes (i) basic conditions (potassium hydroxide, 84 °C, 64 h), membrane Cl, and (ii) acidic conditions with a DMF pretreatment, membrane C3. Finally, the authors concluded that the best results were obtained with an acidic hydrolysis and that membranes based on sulfonic acid-a,, -trifluorostyrene gave better results than those obtained from the phosphonic acid homolog. 

A suitable weight of sample is digested with concentrated sulfuric acid, sodium or potassium sulfate and digestion catalysts using an electrical heater (Note 2). A reagent blank determination is alos carried out. The digested sample, after dilution, is transferred to a steam distillation apparatus. The addition of sodium hydroxide liberates ammonia equivalent to the nitrogen content of the sample. Liberated ammonia is collected in boric acid solution and determined by titration with standard hydrochloric acid. 

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