Acetyltributyl citrate

• USP–NFAcetyltributyl Citrate

ATBC; Citroflex A-4; tributyl acetylcitrate; tributyl O-acetylcitrate

Tributyl 2-acetyloxypropane-1,2,3-tricarboxylate · [77-90-7]

UNII 0ZBX0N59RZ · PubChem CID 6505

C20H34O8 · 402.48

Plasticiser

Typical concentrations: — · Dosage forms: Solid

Used as a plasticiser for polymers in film coatings for tablets, capsules, beads and granules, including enteric and modified-release coatings based on acrylic polymers and cellulose derivatives. It is also used in polymer films and in food-contact plastics. Plasticiser levels are usually expressed relative to the polymer, typically about 10–30% w/w of the dry polymer.

A clear, colourless, practically odourless, oily liquid.

Density

≈ 1.05 g/cm³ at 25 °C

Boiling point

high (above about 320 °C at atmospheric pressure); very low volatility

Refractive index

≈ 1.44 (25 °C)

Solubility

practically insoluble in water; miscible with acetone, ethanol and vegetable oils

Stable. Store in a well-closed container in a cool, dry place.

Incompatible with strong alkalis, which hydrolyse the ester groups, and with strong oxidising agents.

Prepared by esterifying citric acid with n-butanol and then acetylating the remaining hydroxyl group with acetic anhydride; the product is purified by washing and distillation.

Regarded as having low toxicity and as non-irritant at the levels used in oral coatings. It is used widely in food packaging and other consumer plastics as an alternative to phthalate plasticisers.

Observe normal precautions for the quantity handled. Gloves and eye protection are recommended.

Included in the FDA Inactive Ingredient Database (oral capsules and tablets). Permitted in the USA in certain food-contact materials.

Acetyltriethyl citrate; tributyl citrate; triethyl citrate.

Acetyltributyl citrate is far less water-soluble than triethyl citrate, so it leaches less from coatings in aqueous media, but it is harder to incorporate into aqueous polymer dispersions and needs sufficient mixing time to partition into the polymer particles.