Tartrazine

Tartrazine

Names
Systematic IUPAC name Trisodium 5-hydroxy-1-(4-sulfonatophenyl)-4-[(E)-(4-sulfonatophenyl)diazenyl]-1H-pyrazole-3-carboxylate
Properties
Chemical formula	C16H9N4Na3O9S2
Molar mass	534.36
Appearance	Bright yellow solid
Solubility in water	20 g/100 mL
Solubility in glycerol	18 g/100 mL
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Tartrazine, commonly known as FD&C Yellow 5 in the United States, and E102 in the European Union, is a bright yellow azo dye that is one of the most common yellow food colorants.

Properties

Chemical

Tartrazine is highly soluble in water as the trisodium salt, though the free acid is very insoluble in water.

Physical

Tartrazine's maximum absorbance in aqueous solution is 425 nm.

Availability

While tartrazine is present in a wide variety of foods, including being the sole colorant of many brands of pickles and Lemon-Lime flavored Gatorade, the amounts that it is used in are so small that it is not worth isolating from these sources. Readily available yellow food coloring will often contain tartrazine, though it will usually be mixed with Sunset Yellow FCF (FD&C Yellow 6). These two dyes exhibit similar chemical properties, and thus would be difficult to separate, though it may be possible to do so by careful pH adjustment.

Preparation

Tartrazine can be prepared in a multiple step procedure starting with sulfanilic acid and sodium diethyl oxaloacetate.

Handling

Safety

Tartrazine is safe to handle, though it should not be consumed in macroscopic amounts. The amounts used in food are very small. It will not penetrate the skin, but it will stain the surface yellow.

Storage

Tartrazine is very stable and can be stored in virtually any airtight container at room temperature.

Disposal

Tartrazine can be disposed of by washing it down the drain with copious water.

References

Relevant Sciencemadness threads

Synthesis of Tartrazine and Allura Red AC