Isomers and performance: tartaric acid molecule has two asymmetric carbon atoms, so there are three optical isomers, L-tartaric acid or D-tartaric acid, D-tartaric acid or L-tartaric acid, meso-tartaric acid. The same amount of L-tartaric acid and D-tartaric acid was racemic mixture of DL-tartaric acid or tartaric acid. Tartaric acid is a natural right-handed tartaric acid. Industrial production is the largest racemic tartaric acid. D-tartaric acid is colorless transparent crystals or white crystalline powder, odorless, very acid, the relative density of 1.7598. Melting point is 168 ~ 170 ℃. It can soluble in water, soluble in methanol, ethanol, slightly soluble in ether, insoluble in chloroform. DL-tartaric acid as a colorless fine crystal is no odor, the relative density of 1.697. Melting point is about 204 ~ 206 ℃, 210 ℃ decomposition. It also can soluble in water and ethanol, slightly soluble in ether, insoluble in toluene. Tartaric acid is stable in air and it is non-toxic.

Quality indicators
DL-tartaric acid quality indicators:
Indicators of water anhydrous product name
DL-tartaric acid mass fraction /% ≥ 99.5 99.5
Melting range /% 200 ~ 206 200 ~ 206
Sulfate /% ≤ 0.04 0.04
Heating loss /% ≤ 11.5 0.5
Residue on ignition /% ≤ 0.10 0.10

Brief introduction
DL-tartaric acid is a carboxylic acid, present in many plants, such as grapes and tamarind, is the major organic acids of wine. Added as a food antioxidant, can make the food with acidity. Use of tartaric acid is the largest beverage additives. It is the pharmaceutical industry raw materials. In the mirror industry, tartaric acid is an important agent and reducing agent, the formation of silver mirror can control the speed, get a very uniform coating.
Tartaric acid is also called 2, 3-Dhydroxybutanedioic acid . Structure is HOOCCH (OH) CH (OH) COOH. The presence of potassium hydrogen tartrate in grape juice, the salt is insoluble in water and the alcohol, grape juice wine in the process of precipitation, known as tartar, tartaric acid and the resulting name. Tartaric acid exists mainly in the form of potassium in a variety of plants and fruits, is also a small amount of free states exist.