At present, aloe-emodin is mainly obtained by extracting the crude product of aloe vera juice dried at low temperature with ethyl acetate, and then eluting and refining by silica gel column chromatography (petroleum ether-ethyl acetate). However, the amount of aloe-emodin obtained by this method is small, the product purity is not high, and the processing technology is complicated, so it cannot be widely used in fields such as biomedicine and chemical industry.
A kind of preparation technology of aloe-emodin, is characterized in that:
Including step a) using aloe extract as raw material to obtain aloe-emodin crude product through hydrolysis and oxidation;
In step b), the crude aloe-emodin product is purified to obtain the aloe-emodin product.
Preferably, the step a) comprises dissolving the aloe vera extract, leaving the dissolving solution at rest, filtering to remove the filter residue, transferring the clear liquid obtained by filtration, carrying out oxidation treatment of the clear liquid, cooling and crystallization of the oxidized clear liquid and centrifuging, and the obtained precipitate is Aloe-emodin crude O
Preferably, the dissolving aloe extract is carried out in an enamel dissolving kettle or an enamel hydrolysis kettle, and the dissolving environment is a mixed solution with a molar ratio of water and hydrochloric acid of (10:1) to (1:10) as a solvent, and the dissolution temperature 30°C -50°C.
Preferably, the oxidation treatment is to add ferric chloride to the clear liquid for stirring, and the amount of ferric chloride added is 1.2-2 times the weight of the aloe extract.
Preferably, the use time of the standing dissolving solution is 1-10h.
Preferably, the step b) comprises heating and dissolving the crude aloe-emodin product, press-filtering the dissolving solution to obtain the filtrate to remove the filter residue, cooling the filtrate for crystallization, and centrifuging the precipitate to leave the mother liquor to obtain the wet product of aloe-emodin.
Further preferably, the step b) further includes repeating step b) for purification of the filter residue obtained by pressure filtration and the mother liquor left by centrifugation, and the repetition times are preferably more than 2 times.
Further preferably, the temperature of the described heating dissolving aloe-emodin crude product is 40 ℃-50 ℃, and the solvent is toluene, and the quality of toluene is 10-15 times of the aloe-emodin crude product.
Further preferably, the step b) also includes adding methanol to the wet product of the aloe-emodin obtained by centrifugation, centrifuging and drying to obtain the aloe-emodin product, pulverizing the aloe-emodin product after sieving and packaging; The filtrate can be recovered by multiple combined distillations.
Further preferably, the centrifugal rotation speed is 500r/min-1000r/min.
