9069. dl-Tartaric Acid

Nomenclature

CAS number: 133-37-9
2,3-Dihydroxybutanedioic acid; racemic tartaric acid; racemic acid; dl-tartaric acid; resolvable tartaric acid; uvic acid; paratartaric acid; dl-Weinsure (German); Vogesensure (German); Traubensure (German).
C4H6O6; mol wt 150.09.
C 32.01%, H 4.03%, O 63.96%.

Description and references

Probably never a natural product, although sometimes found in small amounts during wine-making. Prepn from l-tartaric acid by boiling with aq NaOH (meso-tartaric acid is obtained as a byproduct): Holleman, Org. Synth. 6, 82 (1926); coll. vol. I (2nd ed., 1941) p 497. Synthesis by oxidation of fumaric acid: Milas, Terry, J. Am. Chem. Soc. 47, 1412 (1925); Milas, Sussman, ibid. 58, 1302 (1936); US 2000213 (1935 to Standard Brands). From maleic acid: Church, Blumberg, Ind. Eng. Chem. 43, 1780 (1951).

Chemical structure

Properties

Anhydr acid, triclinic pinacoidal crystals from abs alc, from water above 73°, or by drying the monohydrate at 100°. mp 206°. pKa1 2.96; pKa2 4.24. Less soluble in water than l-tartaric acid. pH of 0.1M aq soln: 2.0. Soly in alcohol (g/100 g): 2.006 at 0°; 3.153 at 15°; 5.01 at 25°; 6.299 at 40°. Soly in ether about 1%.

Derivative

Monohydrate.

Properties

Triclinic pinacoidal crystals from water. d420 1.697. One hundred parts (w/w) of water dissolve 14.00 parts at 10°; 20.60 at 20°; 29.10 at 30°; 43.32 at 40°; 99.88 at 70°; 184.91 at 100°.