Yield:-

Reaction Conditions:

with sodium tetrahydroborate in water at -1 - 3;Temperature;

Steps:

1-8 Example 2: Preparation of high-purity pentic acid

(1) Dilution: diethylenetriamine (100.05g, 0.97mol) diluted with water (51.23g) by weight about 1:0.5 to obtain diethylenetriamine aqueous solution;(2) Dissolution: add sodium chloroacetate (564.80g, 4.85mol) and sodium borohydride (3.67g, 97mmol) to purified water (1150g), stir to dissolve to obtain a solution containing sodium chloroacetate and sodium borohydride;(3) Reaction: cool down to 0 °C, and then add the above diethylenetriamine solution to the solution containing sodium chloroacetate and sodium borohydride, and control the internal temperature to -1~3 °C;(4) Alkalizing: add sodium hydroxide solution (585.43g, 40% w) to adjust the pH, and maintain the pH ≥13 of the reaction solution during the whole reaction process, control the temperature of -2~1 °C, and react for 3h;(5) Heat preservation: the solution obtained by the alkalinization step is heated to 10±3 °C, and this temperature range is maintained, the reaction is 40h, sampling and detection, when the main peak area ≥ 90% is the end point of the reaction.(6) Cooling: Cool the reaction solution to 10±5 °C.(7) Acidification: add concentrated hydrochloric acid dropwise to the cooling reaction solution, adjust pH=1.2-2.5;(8) Crystallization: cool down to 5±5 °C, add crystal seed, and quickly stir crystallization for 72h;(9) Filtration: filter, wash the solid with 300g of purified water, and obtain crude wet products of pentic acid;(10) One-time refining: add 1000g of water to the crude wet product of pentic acid, heat up to 90±5 °C to dissolve until clear, filter, cool the filtrate to 25±5 °C, crystallization for 12h; Cool down to 10±5 °C, stir and crystallize for 2h, filter, and obtain a refined wet product; 65±5 °C air drying for 5-9h to obtain a refined product.(11) Secondary refining: the pentic acid is refined for a time, add 1000g of water, raise the temperature to 90±5 °C to dissolve until clear, filter, cool the filtrate to 25±5 °C, crystallization for 5h; Cool down to 10±5 °C, stir and precrystallize for 4h, filter, and obtain secondary refined wet products; 65±5 °C air drying for 3-9h, to obtain a finished product of pentic acid, the purity of the pentic acid is 99.987%, and the content of related substance 1 is 0.013%.

References:

CN115650870,2023,A Location in patent:Paragraph 0073-0109