The method for preparing L- and D-camphorsulfonic acid by inducing crystallization and resolving racemic camphorsulfonic acid comprises the following steps:
(1) the preparation of racemic camphorsulfonate:
Raw material proportioning (weight ratio) racemic camphorsulfonic acid: water: =1: 1.2 above-mentioned raw materials are mixed in proportion, heated to be warming up to 50 DEG C and be incubated 3 hours, adjust pH with ammoniacal liquor to be 5, be cooled to 5 DEG C, centrifuge The dry yield of white solid salt was 80%. Mother liquor is recycled.
(2) preparation of D-camphorsulfonate:
The raw material weight ratio is, racemic camphor sulfonate: water: dextrorotatory optical activity inducer=1: 1.2: 0.1, water and racemic camphor sulfonate are mixed and heated to 80 ° C in proportion, and incubated for 2 hours When cooled to 50°C, add an inducer and keep warm for 1 hour, then cool to 20°C and centrifuge to obtain white solid D-camphorsulfonate, the optical rotation of D-camphorsulfonate is [a]D/20=+18‑‑20 . The mother liquor is used for the preparation of L-camphorsulfonate.
(3) Preparation of D-camphorsulfonic acid
The D-camphorsulfonate obtained above is dissolved in water and configured into a 20% aqueous solution, passed through an exchange column equipped with a cation exchange resin, the aqueous solution is collected and then concentrated to anhydrous through vacuum decompression, acetic anhydride solvent is added to crystallize, and the solution is cooled. to 5°C, filtered, and dried to obtain white crystals, the optical rotation of D-camphorsulfonic acid is [a]D/20=+21‑‑23, mp196‑200°C.
A preparation method of optically active left-handed and right-handed camphorsulfonic acid, comprising the following steps:
1. Preparation of racemic sulfonic acid: add 100 kilograms of 98% acetic anhydride and 20 kilograms of acetic acid in 200 liters of enamel reaction kettles with stirring, add 75 kilograms of racemic camphor under stirring and cooling, cool down to 0～5 ℃ and add 98% 55 kilograms of sulfuric acid, then kept temperature 5～30 ℃, reacted 60 hours, cooled to -2～5 ℃ after the reaction, kept 15 hours, centrifugal filtration, washed with acetic acid, vacuum-dried, got 70 kilograms of white crystalline racemic camphor Sulfonic acid, weight yield 93%;
2. 2. Prep work of left-handed and right-handed camphorsulfonic acid, splitting: include 23.2 kgs of racemic camphorsulfonic acid while stirring in a 100-liter enamel kettle, 18 kilograms of splitting agent compositions, 20 kilograms of water, mix and warm to 60 ～100℃ for 1 hour, cool to 5～10℃, keep for 1 hour, filter to obtain D-camphorsulfonic acid double salt, add 3 times the amount of water, heat to 60～100℃, adjust the pH value to 4～7 with ammonia water , and then cooled to 5-10° C. to filter and recover the resolving agent composition. The filtrate is ammonium d-camphorsulfonate solution, and the resolution ratio is 99%. The mother liquor from which the double salt has been filtered is added with ammonia water to neutralize to pH 4-7, cooled to 5-10 DEG C, and the resolving agent composition is filtered out. Filtration: Lots the L-camphorsulfonic acid ammonium salt service and also D-camphorsulfonic acid ammonium salt service into An as well as B chromatographic columns respectively, and slowly accumulate the A-column L-camphorsulfonic acid ammonium salt solution and the B-column D-camphor Sulfonic acid ammonium salt solution, A and B solutions were evaporated and concentrated to anhydrous in a thin film evaporator, then acetic acid and acetic anhydride were added for crystallization, cooled to 5 ~ 25 ° C, filtered, and dried to obtain white crystals, L-camphorsulfonic acid. The optical purity is 99.5%, and the optical purity of D-camphorsulfonic acid is 99.7%.