Making L-Phenylalanine by Benzaldehyde

In this article, I will show you 7 methods to make L-Phenylalanine by Benzaldehyde.

1. Benzaldehyde and acetyl glycine reacts acetamido cinnamic acid, and catalytic hydrogenation, in acetyl-DL-phenylalanine, and finally by aminoacylase hydrolysis can be split to generate L-Phenylalanine(CAS NO: 63-91-2).

2. Using the specificity of aminoacylase, only Ac-L-phe hydrolysis of an amide bond, and not hydrolyze Ac-D-phe amide, generate L-Phenylalanine. Then separate L-Phenylalanine and the Ac-D-phe according the different solubility in water. The separation of the Ac-D-phe racemization can be generated by Ac-DL-phe. Repeating the process of hydrolysis and separation again and again, the Ac-DL-phe can be all converted L-Phenylalanine.

3. Immobilized aminoacylase preparation: DEAE-sephadexa-50 full immersion into deionized water, then washed with 10 times the amount of the solution to mix 0.5mol/LHCl and 0.5mol/LNaOH treatment 30min. Then washed with deionized water to neutral, and finally were with 0.1mol / L and 0.01mol / L of pH = 7.0 phosphate buffer processing 1-2h, drained and set aside. 40-50h of culture learn koji expansion curved, with its support 6 times the amount of water 2 times ions The extract was washed with 2mol / L of NaOH solution to adjust pH to 6.7-7.0. Then the enzyme solution and 1kg 100L wet DEAE-sephadex A-50 mixed in the ratio was stirred at 0-4 ℃ 4-5h after adsorption, filter it DEAE-sephadexA-50, respectively 0.1mol/LNaAc deionized water solution, 0.01mol / L of pH = 7.0 phosphate buffer, washed 3-4 times. Filtration immobilized L-Phenylalanine, plus 1% toluene into cold storage storage backup.

4. Enzymatic hydrolysis: the hydrolysis tank 1000L, adding 700L0.1mol / L of Ac-DL-phe salt solution, and then gradually add 6mol / L of HCl solution was adjusted to pH 6.7-7.0, then add 15-20kg immobilized amino acid enzyme, maintained for about 4h 50 ℃ selective enzymatic hydrolysis reaction, the filtrate was collected by filtration to give the enzyme hydrolyzate of L-Phenylalanine (containing Ac-D-phe mixture).

5. Separation: the enzyme hydrolyzate with 6mol / L of HCl to pH 4.8-5.1, concentrated under reduced pressure to about 35L, and placed overnight at 0 ℃ crystallization, crystals were collected by filtration, washed with cold ethanol 10L, drying at 80 ℃ dry 3-4h, the goods of the crude, and the filtrate and washings were combined and concentrated under reduced pressure to about 20L to give L-Phenylalanine solution, to be repeated after racemization enzymatic hydrolysis, separation.

6. L-Phenylalanine racemization: the L-Phenylalanine was 60L, 100L added to the reaction tank, add acetic anhydride 18.5L, at 25-45 ℃, stirred for 30min, cool place 6h. Then concentrated HCl to adjust pH to 1.5-2.0,5 ℃ crystallization overnight, crystals were collected by filtration, washed, drained 40 ℃ vacuum drying, L-Phenylalanine.

7. Refining: the 100L reactor, adding 5kg of the crude L-Phenylalanine, add 50L of deionized water, heated to 100 ℃, stirring to fully dissolve, then add the pharmaceutical active carbon 0.25kg, stirred for half an hour after bleaching, hot filtration, 200L crystallization filtrate into the tank, cooled to 40 ℃, adding 50L, 40 ℃ 95% ethanol, with 6mol / L of HCl to adjust the pH to 5.48, at 0 ℃ crystallization overnight, crystals were collected by filtration, washed with 95% ethanol, pumping dry, 80 ℃ drying 3-4h, was the product of the finished L-Phenylalanine. Mother liquor can recycle.

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