Purification of sodium formate with formic acid
Apr 09, 2021
The use of sodium formate has been a concern for a long time. For it, we also mentioned that it has an inseparable relationship with formic acid, which reminds many people whether formic acid can be made into sodium formate? What do you think? Some people think it is OK, others have the opposite idea. What is the result? Let's go and see it together.
Take 212g sodium carbonate and heat it into 1L water, add a small amount of formic acid water solution to the water solution. At this time, impurities can be removed from the solution while forming sodium formate precipitation. Then, 252g of refined formic acid is dissolved in 1L hot water (90 ℃), in the beaker, 500ml of water heat is pre heated to 90 ℃, under stirring, the volume of formic acid and sodium carbonate aqueous solution is slowly dropped into the beaker with a separating funnel. The pH value of the solution should be kept at 6-7 during this process. After dropping, after a little heating, cool the solution and filter out the crystal. Wash it with cold water, dry the crystal at 240-250 ℃, and then put it in a desiccator with concentrated sulfuric acid.
The sodium formate obtained by the above method or sold in the market can be purified by recrystallization of water. Dissolve it with hot water, and then saturate at about 90 ℃, then add 75% (volume fraction) ethanol water solution to the filtrate while it is hot, cool it, filter out the crystal, and dry at 250 ℃. Because its aqueous solution can react with glassware, and because of impurities in raw materials, it contains silicon dichloride and sodium carbonate in the product. It is suggested that attention should be paid to the preparation operation as soon as possible, and refined sodium hydroxide can be used instead of sodium carbonate. In addition, when preparing it, if the solution is acidic, a small amount of sodium formate will be generated, precipitated and precipitated with it. If the product is dried at 250-300 ℃, sodium formate can be decomposed into sodium carbonate by thermal decomposition.
