Solubility of Potassium Carbonate and Potassium Hydrocarbonate in Methanol

Abstract

The solubility of potassium carbonate in methanol and the acid-base interaction of these compounds with each other have been considered. The reaction results in the formation of methoxide and hydrocarbonate of potassium. The reported values on the solubility of potassium carbonate differ essentially from the data described in the literature. The solubility of potassium hydrocarbonate in methanol has also been determined.The solubilities of potassium carbonate in alcohols as well as other carbonates have been studied previously. [1][2][3] However, the authors of the papers did not take into account the possible reaction between carbonate of alkali metal as the base and alcohol as the acid where M is an alkali metal and R is an alkyl group.Loder and Lee 4 reported the formation and the recovery of alkoxides according to eq 1 for the first time. They offered the process for the preparation of potassium methoxide wherein 8.6 parts of K 2 CO 3 and 94.6 parts of CH 3 OH reacted at 20°C for 6 h. The solid KHCO 3 precipitated from a reaction mixture was filtered out. The remaining carbonates were separated by evaporating methanol from the solution, and then the carbonates precipitated were readily filtered from the saturated potassium methoxide solution. This latter solution may be further evaporated to obtain solid potassium methoxide.Studying the reactions of diethyl phosphite with electrophiles in the K 2 CO 3 /C 2 H 5 OH system, we established the formation of potassium ethoxide after stirring of potassium carbonate with ethanol using a titrimetric method. 5 In the present paper, the solubility of K 2 CO 3 in methanol was determined in view of the above interaction. In addition, the distribution of all components in the K 2 CO 3 / CH 3 OH system was investigated under the conditions of phase and chemical equilibrium. The solubility of KHCO 3 in anhydrous methanol was also determined. Experimental SectionReagents. As far as possible, anhydrous chemicals were used. After dehydration, the methanol obtained from Merck was stored above molecular sieves type 3A. The water content in the methanol was controlled by the GC method and did not exceed 0.02 mass %. Potassium carbonate and potassium hydrocarbonate obtained from Aldrich (ReagentPlusTM) had a purity of 99.99 mass %. Before the experiment, the potassium carbonate was warmed to 120°C for 1 h. Procedure.The equilibrium concentrations of the components of K 2 CO 3 /CH 3 OH and KHCO 3 /CH 3 OH systems were determined using the titrimetric method. For this purpose, a mixture of the appropriate carbonate (a known mass of sample from 2.8 to 6.8 g) and 10 mL of methanol was continuously agitated within 6 h in a temperaturecontrolled cell at either (25 ( 0.05°C) or (35 ( 0.05°C). Then the suspension was passed through a porous glass filter under pressure. The solid and liquid phases were treated with water separately. The concentrations of K 2 CO 3 , KHCO 3 , and CH 3 OK were determined by hydrochloric acid solution using phenolphthalein and methyl orange solutions as the ind...

Biodiesel Production from Jatropha curcas Oil Using Potassium Carbonate as an Unsupported Catalyst

“…the concentration of CH 3 OK decreased and, at the same time, the concentration of K 2 CO 3 increased (Platonov et al, 2002). However, KHCO 3 was found to be a poor catalyst with negligible catalytic activity when compared to that of K 2 CO 3 (Arzamendi et al, 2008).…”

“…A previous study on the solubility of anhydrous potassium carbonate in methanol showed that potassium carbonate and methanol undergo a reversible reaction in the following way (Platonov et al, 2002):…”

Experimental and modelling approach to the catalytic coproduction of glycerol carbonate and ethylene glycol as a means to valorise glycerol

“…Potassium carbonate, while fully soluble in water, is scarcely soluble in organic solvents, but can react with alcohols to render the corresponding bicarbonates and alkoxides (in this case, potassium glyceroxide) [49] . Possible reactions of substitution of hydrogen atoms by potassium atoms in glycerol molecules are:…”

Solubility of potassium and sodium orthophosphates in ethylene glycol

“…Data on the solubility of acid and neutral orthophosphates of alkali metals in other alcohols, glycols, cellosolves, and glycerin are absent. It is known [6][7][8][9][10][11][12][13] that the alcoholysis of weak-acid salts (carbonates, orthophosphates, sulfi des, and cyanides), of organometallic compounds, and other derivatives of alkali metals, such as acetylenides, amides, hydrides, nitrides, and azides, can be considered as a mode of preparation of corresponding alcoholates, whereas the alcoholysis of hydroxides is one of industrial methods of producing potassium and sodium alcoholates:…”

“…Earlier distributions of components over phases in methanolysis reactions of potassium hydroxide and carbonate and also in alcoholysis of sodium sulfi de under the action of various alcohols [9][10][11] were determined. Furthermore it was found that the methanolysis of potassium hydrocarbonate does not occur [9]. It was reported in the patent [6] that glycolates are formed in reactions of orthophosphates, cyanides, and carbonates of alkali metals with ethylene glycol and propylene glycol.…”