Tartaric acid

From Sciencemadness Wiki
Jump to: navigation, search
Tartaric acid
Tartaric acid.png
Commercially available tartaric acid crystals
Names
IUPAC name
2,3-Dihydroxybutanedioic acid
Other names
2,3-Dihydroxysuccinic acid
E334
Paratartaric acid
Racemic acid
Threaric acid
Uvic acid
Properties
C4H6O6
Molar mass 150.087 g/mol
Appearance Crystalline solid
Odor Odorless
Density 1.79 g/cm3
Melting point D-(−)-Tartaric acid
172-174 °C
L-(+)-Tartaric acid
170-172 °C
racemic
210-212 °C
meso-Tartaric acid
165-166 °C
Boiling point Decomposes
L or D-tartaric
20.6 g/100 ml
DL, racemic
21 g/100 ml
meso
125 g/100 ml
Solubility Soluble in ethanol
Poorly soluble in glacial acetic acid, diethyl ether, isobutanol
Insoluble in chloroform, dichloromethane
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Sigma-Aldrich (levo)
Sigma-Aldrich (dextro)
Sigma-Aldrich (racemic)
Sigma-Aldrich (meso)
Related compounds
Related compounds
Potassium bitartrate
Succinic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Tartaric acid is a white crystalline organic acid which occurs naturally in many plants, most notably in fruits, such as grapes. One of its salts, potassium bitartrate, commonly known as cream of tartar, is formed naturally in the process of winemaking.

Naturally occurring tartaric acid is chiral, and is a useful raw material in organic chemistry for the synthesis. The naturally occurring form of the acid is dextrotartaric acid or D-(-)-tartaric acid.

Properties

Chemical

Partial neutralization of tartaric acid with potassium hydroxide or bicarbonate will give potassium bitartrate, also known as cream of tartar. This can be done by mixing equimolar amounts of the two reagents.

HOOC-CH(OH)-CH(OH)-COOH + KOH → HOOC-CH2-CH2-COOK + H2O
HOOC-CH(OH)-CH(OH)-COOH + KHCO3 → HOOC-CH2-CH2-COOK + H2O + CO2

Reaction of tartaric acid with hydrogen peroxide in the presence of a ferrous salt will yield dihydroxymaleic acid.

HOOC-CH(OH)-CH(OH)-COOH + H2O2 → HOOC-C(OH)=C(OH)-COOH + 2 H2O

Tartaric acid can be reduced to succinic acid. A chemical method, which uses hydrogen has been developed. The catalyst used consists of molybdenum oxide supported on carbon black (MoOx/BC). The reaction solvent consists of a mixture of hydrobromic acid and glacial acetic acid. At 170 °C, the yield of this process is 87%.[1]

HOOC-CH(OH)-CH(OH)-COOH + H2 → HOOC-CH2-CH2-COOH + 2 H2O

Physical

Tartaric acid is a crystalline colorless solid, soluble in water, acids and alcohols, but insoluble in hydrocarbons and halocarbons.

Availability

Tartaric acid is sometimes sold as descaling agent, sometimes mixed with citric acid.

Tartaric acid is available in many winemaking and agricultural stores, though it's more commonly found in the form of potassium bitartrate (cream of tartar) rather than pure acid.

Both racemic and isomeric tartaric acid can be purchased from chemical suppliers.

Preparation

Tartaric acid can be made by acidifying potassium bitartrate, which can be extracted from wine fermentation products (lees) or purchased from the store.

HOOC-CH(OH)-CH(OH)-COOK + HCl → HOOC-CH(OH)-CH(OH)-COOH + KCl

Projects

  • Grow large and beautiful crystals
  • Demonstration of chirality in organic compounds
  • Make cream of tartar
  • Make dihydroxymaleic acid
  • Preparation of potassium antimony tartrate

Handling

Safety

Tartaric acid has low toxicity and it's approved as food additive.

Storage

Tartaric acid should be kept in closed plastic or glass bottles. No special storage conditions are required, though it's best to be kept away from light.

Disposal

No special disposal is required. Discard it as you wish.

References

  1. http://pubs.rsc.org/en/content/articlelanding/2017/cy/c7cy01374d#!divAbstract

Relevant Sciencemadness threads