The industrial production methods of tartaric acid mainly have four kinds, such as extraction method, chemical synthesis method, semi-synthesis method and fermentation method.
1. Extraction method Tartaric acid was first extracted from the by-product wine stone of brewing wine. When brewing wine, some stones, the coarse wine stone, are often deposited at the bottom of the barrel, the main components of which are tartaric acid and its hydrogen potassium salt. The wine stone is crushed, dissolved and reacts with calcium hydroxide, and then added calcium chloride, so that it is all converted into calcium salt. Acidified with slightly excessive sulfuric acid, free tartaric acid is obtained, and solid tartaric acid is obtained by concentration, refining and drying. This process is simpler and less expensive.
However, due to the unstable source of the wine stone, the production is limited, not suitable for the industrial mass production of tartaric acid.
2. Chemical Synthesis method
1) oxidized benzene or naphthalene obtained maleic acid and anti-butene acid, and then added hydrogen peroxide reaction to the production of dl-tartaric acid.
2) with maleic anhydride as raw material, hydrogen peroxide as oxidant, tungsten acid as catalyst, catalytic oxidation to produce epoxy butyric acid, and then through hydrolysis can be produced tartrate, and then after cooling, crystallization, separation, drying tartaric acid finished products.
3. Semi-synthetic method Semi-synthetic method is a combination of chemical synthesis method and enzyme method (fermentation method). The maleic acid was first formed by cyclic oxidation and its salt, and then hydrolyzed by epoxy succinic hydrolysis enzyme was used to obtain tartaric acid. Another route is to use the cis-epoxy succinic acid salt as a precursor, and then ferment the production to obtain tartrate. At present, the biotransformation rate of tartaric acid was 100% by laboratory fermentation with cis-epoxy sodium succinate as substrate.
Semi-synthetic method has the characteristics of high conversion rate, high purity of product and good safety.
4. Fermentation method Microbial bacteria were used to convert carbon-containing compounds such as glucose and its derivatives, organic acids, amino acids, alcohols and other carbon sources to produce tartaric acid. In the early 70, Japan used the Gluconobacter Suborydans mutant strain to convert glucose into tartaric acid, with a yield of about 20~30%.
Generally speaking, there is less investment in production by fermentation, the cost is only a fraction of the chemical synthesis method, the operation is simple, the source of raw materials is wide, and there is no pollution problem caused by chemical method.