Method for preparing coking gallic acid

Method for preparing coking gallic acid

  • CN 102,140,056 A
  • Filed: 01/28/2010
  • Published: 08/03/2011
  • Est. Priority Date: 01/28/2010
  • Status: Active Application
First Claim
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1. One kind with the quinoline be solvent, copper powder be catalyzer decarboxylation prepares the method for pyrogallol as gallic acid, it is characterized in that may further comprise the steps:

  • The first step, with anhydrous gallic acid dispersing and dissolving in quinoline (A) solution, the solid-to-liquid ratio of anhydrous gallic acid and A is 1;

    4~

    7, add copper powder (B) catalyzer, the add-on of B and the mol ratio of anhydrous gallic acid are 0.15~

    0.20;

    1, mix, 130~

    184 ℃

    of following back flow reaction, the gallic acid material is dispersed in the A solution with molten state, has a large amount of CO2 bubbles to overflow simultaneously, and insulation no bubble in reaction product is overflowed.In second step, keeping the temperature of reaction product is 120~

    170 ℃

    , and makes above-mentioned reaction product underpressure distillation, and pressure reduces to 2kPa, distills out the A solvent in the feed liquid.Can adopt the two lines purification operations to the reaction product that steams A.The 3rd step (route one) added ether solvent (D) dissolving to the reaction product that steams A, and dissolution fluid filters, and reclaims solid substance, and the stripping filtered liquid heats up, insulation, reclaims D.Steam the enriched material that obtains behind the D, add 30~

    60 ℃

    of sherwood oils (E) solvent, slowly refluxing in water-bath dissolves it fully, produces lysate while hot and carries out crystallisation by cooling, filtration, obtain white or beige to pyrogallol product 3, filtered liquid E reuses.The 4th step (route two) was controlled at 150~

    170 ℃

    with the temperature of the product behind the above-mentioned A of removing, and carried out underpressure distillation, and pressure-controlling is collected the distilled flores, till no flores distillates at 5~

    2kPa.Collect the distilled flores and be pyrogallol product 1.The 5th step, or above-mentioned flores is added in the chloroform (C) of 3~

    7 times of flores weight agitator treating, make the impurity that participates in be dissolved among the C, filtering separation, and use C drip washing, filter is carried out vacuum-drying after doing, and 35~

    55 ℃

    of drying temperatures get pyrogallol product 2.

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