Study On The Cleaning Production Technology Of Gallic Acid

Gallic acid is a kind of widely used raw materials, can be used in medicine, such as such as anti-cancer, anti-inflammatory effect, it also can be applied to many fields such as chemical industry, for leather, ink, and cosmetics。It is also a kind of highly active biological polyphenols, and the demand is higher and higher。Tannins are main raw material for producing gallic acid。Tannic acid is the main ingredient in Chinese traditional medicine gallnut, and it also has the very high biological activity and medicinal function。 Hydrolyzed tannins traditional craft production, is a chemical method of gallic acid, namely using a high concentration of sulfuric acid and sodium hydroxide get gallic acid hydrolysis, it brings the environment pollution。So in this paper on the basis of the original process to reduce acid concentration and recipients of volatile acid recycling, and using the characteristic of the tannin enzyme hydrolysis experiment was carried out, thus reducing environmental problems. In the purification of gallic acid and tannic acid products also did a series of improvements。The content and main results are listed as below:1、The cleaning production technology of gallic acid① the traditional experimental using of concentration is more than 8% of the sulfuric acid and pure NaOH hydrolyzed tannins。We are still taking sulfuric acid as catalyst, but its concentration below 3%, through orthogonal and experiments on the response surface, it can be the best technology of hydrolyzed tannins:concentration of 2.5%, Reaction temperature is 150 ℃, and solid-liquid ratio of 1:10, reaction time is 8 h, but the basic reaction is completely (1% gelatin generating white precipitate) 。② Using of volatile acid sulfite experiment。 In industry can take advantage of the sulfur dioxide generated sulfurous acid and sulfite as recycling 。 The best available technology of experiment:the reaction temperature 145 ℃; reaction time 8 h; and solid-liquid ratio of 1:10, acid concentration of 6% sulfite, and the conversion rate reached 85% (because of the instrument, this is the biggest limit of reaction under laboratory conditions).,③ Using hydrochloric acid and sulfite can achieve the same effect (because hydrochloric acid also has the intelligence) for a while 。 Using hydrochloric acid concentration below 4%, the optimal process parameters as follows:reaction temperature 130℃, the acid concentration was 4%, the material liquid than the latter, the reaction time is 8 h, up to about 95。2、Purification experiment of Tannic acid use D201, the fluid volume is 1. 5 BV, the best solution concentration was (material liquid than 1:20), liquid flow rate is 1.5 BV/h on best under the conditions of tannic acid purification o The first water leaching at a speed of 2 bv/h; With 1.5 BV 75% ethanol to 1.5 BV/h elution, the purity of tannins products can reach between 96% and 97%。3、The cleaning process of recycling gallic acid from the acid crystallization mother liquor。Because a single performance only can be a purification index of resin。So, in order to better recovery and purification of gallic acid products, that can use a few resin column series method。First use resin to explore:10 g 001* 1 and 10 g D301 resin column, sample speed control in 2-3ml/min, reoccupy by 10 BV,100% ethanol elution solution, ethanol steam out, and then to evaporation and cooling crystallization。 Determination of the gallic acid content in solution can be below 0.1%, the purity of gallic acid is over 98.5%, recovery rate is about 80%。So this research plan is effective, the study is to search for optimum process conditions of two kinds of resin series, in order to achieve the research purpose。...