Separating and purifying method of crude isovanillin

Separating and purifying method of crude isovanillin

  • CN 103,254,048 A
  • Filed: 02/16/2012
  • Published: 08/21/2013
  • Est. Priority Date: 02/16/2012
  • Status: Active Application
First Claim
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1. the separation purification method of an Isovanillin crude product, it is characterized in that:

  • the Isovanillin crude product is the synthetic Isovanillin crude product of 3,4-Dihydroxy benzaldehyde selective methylation reaction, wherein contains Isovanillin 91wt~

    93wt%, vanillin food grade,1000.000000ine mesh 5wt~

    6wt%, veratryl aldehyde 2wt~

    3wt%;

    Concrete separating step is as follows;

    In the reactor that stirring is housed, add Isovanillin crude product and 30~

    32wt% sodium hydroxide solution successively, the weight ratio of sodium hydroxide and crude product is 8~

    10;

    1, stir, be warming up to 50 ℃

    , material is dissolved fully, system pH>

    11.5 add the benzene extraction then, tell the benzene layer that is rich in veratryl aldehyde, normal pressure steams solvent benzol, and underpressure distillation gets veratryl aldehyde then;

    The water that contains Isovanillin and vanillin food grade,1000.000000ine mesh sodium salt after the benzene extraction adds 10~

    15wt% dilution heat of sulfuric acid, making system pH is 5~

    6,20~

    55 ℃

    of hierarchy of control Tcs, the phenolic hydroxyl group sodium of Isovanillin at first changes into phenol, forming precipitation from aqueous phase separates out, filter out after the precipitation, with benzene continuous extraction water, behind the separatory, the organic phase normal pressure steams solvent benzol, and remaining solid merges with precipitation, rectifying tower with 12~

    15 theoretical stages, carry out negative pressure rectifying, under vacuum tightness 15mmHg state, collect 178~

    179 ℃

    of cuts and get the Isovanillin product;

    Water behind the benzene extraction Isovanillin adds 10~

    15wt% dilution heat of sulfuric acid, and making the pH value is 30~

    40 ℃

    of 1~

    2. hierarchy of control temperature, the vanillin food grade,1000.000000ine mesh sodium salt all changes into vanillin food grade,1000.000000ine mesh, then with the benzene extraction, after separating, normal pressure steams solvent benzol, and underpressure distillation gets vanillin food grade,1000.000000ine mesh then.

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