Acetylenedicarboxylic Acid: Properties, Uses & FAQs

Acetylenedicarboxylic acid is a linear alkyne diacid (HOOC–C≡C–COOH) notable for its strong acidity and ready solubility in water, ethanol, and diethyl ether, making it a versatile building block in organic synthesis and materials research.

Chemical Name

Acetylenedicarboxylic acid (but-2-ynedioic acid)

Solubility

Soluble in water, ethanol, and diethyl ether

Acidity

Strongly acidic; bears two carboxylic acid groups activated by the electron-withdrawing alkyne

Functional Groups

Terminal alkyne (C≡C) and two carboxylic acid (–COOH) groups

SKU (Aladdin)

A113362

Typical Applications

Cycloaddition reactions, MOF synthesis, polymer precursors, organocatalysis

What Is Acetylenedicarboxylic Acid?

Acetylenedicarboxylic acid (also known as but-2-ynedioic acid, ADCA, or propiolate diacid) is a small, symmetrical organic molecule with the molecular formula C₄H₂O₄. Its structure consists of a central carbon–carbon triple bond flanked by two carboxylic acid groups: HOOC–C≡C–COOH. This combination of an electron-deficient alkyne and two acidic termini gives the compound its characteristic strong acidity and high reactivity in a range of organic transformations.

The molecule is a solid at room temperature and is commercially available from Aladdin Scientific (SKU A113362) for research and synthetic applications.

Solubility and Physical Properties

Acetylenedicarboxylic acid is soluble in water, ethanol, and diethyl ether. This broad solubility profile makes it convenient to use across a variety of reaction media, including protic and aprotic solvents. Researchers working in aqueous or mixed-solvent systems will find it readily dissolves without requiring harsh heating in most cases.

The compound is strongly acidic due to the presence of two carboxylic acid groups that are further activated by the electron-withdrawing effect of the triple bond. This enhanced acidity compared to saturated analogues (such as succinic acid) is an important consideration when designing reaction conditions, selecting buffers, or working with base-sensitive substrates.

Key physical attributes (verify against current Certificate of Analysis):

• Appearance: White to off-white crystalline solid
• Solubility: Water, ethanol, diethyl ether
• Acidity: Strong (pKa values lower than typical aliphatic diacids)

Research and Synthetic Applications

Acetylenedicarboxylic acid is a multifunctional reagent valued in several areas of modern chemistry:

• Cycloaddition chemistry: The electron-poor alkyne is an excellent dienophile in Diels–Alder reactions and a dipolarophile in 1,3-dipolar cycloadditions, enabling rapid construction of carbocyclic and heterocyclic ring systems.
• Metal–organic frameworks (MOFs): As a linear ditopic linker, acetylenedicarboxylic acid is used to bridge metal nodes in the assembly of porous coordination networks with well-defined pore geometries.
• Polymer science: It serves as a monomer or crosslinker precursor, and its alkyne functionality is compatible with click chemistry approaches (e.g., copper-catalyzed azide–alkyne cycloaddition, CuAAC).
• Organocatalysis and total synthesis: The molecule appears as an activated acceptor in Michael additions and other conjugate-addition cascades used in natural product synthesis.

Its combination of reactivity, solubility, and commercial availability makes it a practical choice for both exploratory and preparative-scale work.

Handling, Storage and Safety Considerations

Because acetylenedicarboxylic acid is strongly acidic, standard laboratory precautions for corrosive organic acids apply:

• Personal protective equipment: Wear appropriate gloves (e.g., nitrile), safety glasses, and a lab coat. Work in a well-ventilated area or fume hood.
• Storage: Store in a tightly sealed container in a cool, dry place, away from bases and moisture. Refer to the product's Safety Data Sheet (SDS) for specific storage temperature recommendations.
• Stability: The compound may undergo decarboxylation on prolonged heating or under strongly basic conditions, generating reactive intermediates. Avoid exposure to strong bases or elevated temperatures unless required by the reaction protocol.
• Disposal: Dispose of in accordance with local regulations for organic acid waste.

Always consult the current SDS provided by Aladdin Scientific before use.

Ordering and Specifications

Aladdin Scientific supplies acetylenedicarboxylic acid under SKU A113362. When placing an order or evaluating the product for your application, consider the following:

• Purity: Check the current Certificate of Analysis (CoA) on the Aladdin Scientific website for lot-specific purity data, as specifications may vary by lot.
• Pack sizes: Multiple pack sizes may be available; contact Aladdin Scientific customer service or visit the product page for current availability and pricing.
• Lead time and shipping: Standard reagents are typically shipped from stock; confirm lead times with your regional Aladdin Scientific representative for bulk or custom quantities.
• Regulatory compliance: Confirm any import/export requirements with your procurement team before ordering internationally.

Frequently asked questions

Is acetylenedicarboxylic acid soluble in water?

Yes. Acetylenedicarboxylic acid is soluble in water, as well as in ethanol and diethyl ether, making it easy to use in a wide variety of reaction systems. Because it is strongly acidic, aqueous solutions will have a low pH; handle accordingly.

Why is acetylenedicarboxylic acid considered strongly acidic?

Acetylenedicarboxylic acid carries two carboxylic acid groups directly attached to a carbon–carbon triple bond. The alkyne is electron-withdrawing, which stabilises the conjugate bases and lowers the pKa values of both carboxylic acid groups relative to saturated diacid analogues such as succinic acid. This makes it significantly more acidic than typical aliphatic dicarboxylic acids.

What are the main synthetic uses of acetylenedicarboxylic acid?

It is widely used as an electron-deficient dienophile in Diels–Alder cycloadditions, a dipolarophile in 1,3-dipolar cycloadditions, a linker in metal–organic framework (MOF) synthesis, and an activated Michael acceptor in cascade reactions. Its alkyne functionality also makes it compatible with CuAAC click chemistry.

How should acetylenedicarboxylic acid be stored?

Store acetylenedicarboxylic acid in a tightly sealed container in a cool, dry place, away from bases and sources of moisture. Consult the Aladdin Scientific Safety Data Sheet (SDS) for lot-specific storage temperature and any additional precautions.

Can acetylenedicarboxylic acid undergo decarboxylation?

Yes. Like many activated diacids, acetylenedicarboxylic acid is susceptible to decarboxylation, particularly upon prolonged heating or exposure to strongly basic conditions. Reaction conditions should be carefully controlled to avoid unintended loss of the carboxylic acid groups, unless decarboxylation is the desired transformation.

What is the Aladdin Scientific SKU for acetylenedicarboxylic acid?

Acetylenedicarboxylic acid is available from Aladdin Scientific under SKU A113362. Visit the Aladdin Scientific website or contact customer service for current pricing, pack sizes, and availability.

References

1. Aladdin Scientific product page: Acetylenedicarboxylic acid, SKU A113362. Product description states solubility in water, ethanol and diethyl ether, and strong acidity.
2. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. Wiley. (General reference for Diels-Alder and 1,3-dipolar cycloaddition reactivity of electron-deficient alkynes.)
3. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry. Oxford University Press. (General reference for acidity of carboxylic acids and electron-withdrawing effects of alkynes.)

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