Coupling type heating method for preparing pyrogallic acid

A pyrogallic acid and coupled technology, which is applied in the field of coupled heating to produce pyrogallic acid, can solve problems such as unreasonable energy use, poor crystallizer cooling effect, unstable product quality, etc., and achieve stable and reliable quality and high product raw materials The effect of low consumption and short discharge time

Inactive Publication Date: 2007-09-12
保廷荣
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Problems solved by technology

This method has the following disadvantages: ① low production efficiency, high energy consumption, and unreasonable energy use; ② small heating area, low production efficiency; ③ carbonization of materials during heating, increasing raw material loss; ④ material sublimation process is one In the gradual coking process, the temperature of the electric heating system needs to be adjusted continuously as the thickness of the coking layer changes. The whole process becomes a variable temperature heating process, and the temperature is not easy to control, resulting in unstable product quality; Its cooling effect is easy to change with the change of climate. When the external temperature is high, the cooling effect of the crystallizer is poor, so that part of the sublimation gas cannot crystallize and escape with the decarboxylation gas, resulting in a decrease in yield
In order to overcome the above deficiencies, some manufacturers have changed the heating method. For example, Chinese Patent No. 03117943.6 "A Production Method for Pyrogallic Acid". The sublimation temperature of gallic acid is 170°C under a vacuum of 0.6-0.8 MPa, and there is no possibility of producing pyrogallic acid

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  • Coupling type heating method for preparing pyrogallic acid

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Embodiment Construction

[0019] As the method for producing pyrogallic acid shown in the accompanying drawing, 100 kg of raw material gallic acid is added to the drier 25, and the gallic acid is dried by secondary steam with a temperature of 240° C., dried for 4 hours and discharged, and the residual steam of the dried raw material gallic acid, After passing through the flow divider 27 and the condensing hot water bucket 28 , the condensed water returns to the coupler 4 as supplementary water; the supplementary water required by the coupler is mainly supplied by the supplementary water device 30 . Open the top cover of sublimator 22 then, add the gallic acid that has dried from here. At the same time, add high boiling point medium superheater cylinder oil into coupler 4 and heater 1, observe the oil level from the expansion oil seal to make it have the required liquid level; add water medium into the shell of the evaporation section of coupler 4 , observe the water level gauge 2 located on the evapora...

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Abstract

The invention discloses a process for preparing pyrogallol through coupled heating, which comprises using gallic acid as raw material, carrying out intermittent process flows including drying, sublimation, cooling down crystallization and vacuum decarboxylation with a totally coupled heating system and a semi-coupled cooling system, thus the pyrogallic acid can be crystallized and separated.

Description

technical field [0001] The present invention belongs to the production method of polyhydroxybenzene compound, specifically belongs to the production method of pyrogallic acid. Background technique [0002] Pyrogallic acid, also known as pyrogallic acid, its scientific name is pyrogallol or 1,2,3-pyrogallol. For the manufacture of azo dyes, anthraquinone dyes, etc., and for gas analysis and as a developer. [0003] There are two kinds of process routes for the production of pyrogallic acid: chemical method and sublimation method. The chemical method uses cyclohexanone, cyclohexanol, resorcinol, etc. as raw materials for chemical synthesis. This method has the disadvantages of not being able to eliminate solvent residues in the finished product, long process route, and large investment in equipment. The sublimation method uses gallic acid as a raw material and is prepared through decarboxylation. The decarboxylation sublimation process requires heating. It is usually heate...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/00C07C39/04
Inventor 保廷荣
Owner 保廷荣
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