Several methods for the synthesis of pyridoxal salt acid

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This post was last edited by yacoochem on 2015-8-28 08:07. Pyridoxal hydrochloride is a derivative of vitamin B6, and it plays a very important role in various industries. Research on its synthesis methods is also ongoing; currently, the main method for producing it involves the oxidation of pyridoxal hydrochloride to yield pyridoxal hydrochloride. There are roughly three types of synthesis methods: Method 1: Ahens H； Korytnyk W. (J. Heterocycl. Chem. Vol. 4, 1967: 625–626) reported the selective oxidation of pyridoxine hydrochloride using manganese dioxide to yield pyridoxal hydrochloride. This process uses manganese dioxide as an oxidant, generating large amounts of manganese-containing wastewater, which is difficult to treat and harmful to the environment ； Option 2: More Ashok. (Spectrochimica Acta Part A, Vol. 72, 2009: 204–208) reported the selective oxidation of pyridoxine hydrochloride to pyridoxal hydrochloride using H2O2 as an oxidant and a dichlorotris(triphenylphosphine)ruthenium complex as a catalyst. The drawback of this process is the use of the transition metal Ru, which is expensive; it currently lacks industrial applicability and requires further development by researchers. Option 3: Pyridoxine or its salt. Pyridoxine acid is used as the starting material, with water serving as the reaction solvent. Under the action of a catalytic oxidation system, pyridoxine or its salt/pyridoxine acid is selectively oxidized in water to yield pyridoxal or its salt/pyridoxal acid as shown in Formula (Ⅰ) ； This process features high conversion efficiency, good selectivity, mild reaction conditions, easy operation, low cost, and environmental friendliness, making it highly suitable for industrial application. As an important compound, pyridoxal phosphate has broad market prospects. It is available in two grades: industrial grade and pharmaceutical grade. The industrial grade has a purity of ≥97.0%, a dry loss of ≤0.5%, a pH value (in 1% aqueous solution) of 2.0–4.0, and a burning residue of ≤2.0% ； Pharmaceutical grade: ≥99.0%, loss on drying: ≤0.5%, sulfate ions: ≤500ppm, pH (1% aqueous solution): 2.0–4.0, residue on ignition: ≤0.1%, chlorides: 17.2–17.7%, nitrogen: 6.7–7.3%. Related reading: Salt, Pyridoxal acid