D-Gluconic acid, copper salt (1:?)

The fermentation method uses glucose as a raw material, which is fermented and oxidized by black mold to generate gluconic acid, and then reacts with copper carbonate (or basic copper carbonate) to generate copper gluconate. This method has huge production equipment, high concentration energy consumption, and difficulty in purification and crystallization. The direct method directly reacts calcium gluconate with copper sulfate to produce copper gluconate. The process of this method is simple, but the residual calcium sulfate is difficult to remove. The chemical oxidation method uses glucose as a raw material, oxidizes it to gluconic acid with ozone, and then concentrates and dehydrates under reduced pressure to obtain zanolactone, which is then reacted with copper carbonate to produce copper gluconate. Acidification method adds 1.2 mol of calcium gluconate to an equimolar sulfuric acid solution, reacts at 60-90°C for 1 to 2 hours, and filters the precipitated calcium sulfate while it is hot to obtain a colorless or light yellow gluconic acid solution (relative to Density 1.12～1.16). 4g of barium hydroxide aqueous solution and 1.5g of oxalic acid aqueous solution were added dropwise to the above gluconic acid solution, and the reaction was stirred for 15 minutes to remove residual Ca2+ and S02-. The purified solution is passed through anion and cation exchange resin to obtain a colorless and transparent gluconic acid solution. In addition, 1 mol crystalline copper sulfate solution is mixed with 2 mol sodium hydroxide solution, reacted at 40-60°C for 0.5-1h, filtered, and the filter cake is washed with water to obtain black copper oxide crystals. The copper oxide crystals were added to the gluconic acid solution in batches, reacted for 1 hour, filtered to remove unreacted materials, and allowed to cool and stand for 3 to 5 hours to precipitate crystals. Add an appropriate amount of 95% ethanol, stir to form a paste, and filter. The filter cake is vacuum dried at 50°C to obtain a finished product with a yield of 90%-92.5%. (C6H1lO7)2Ca+H2SO4→2C6Hn07+CaS04↓2C6H12O7+CuO→(C6H11O7)2Cu+H2O

Copper gluconate is a good nutrient fortifier. China~"s regulations can be used in infant formula food, the amount of use is 7.5 ~ 10mg/kg (calculated as copper, the same below); in dairy products is 5.7 ~ 7.5mg/kg .