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Maleic Acid vs. Fumaric Acid: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on December 25, 2023
Maleic acid is a cis isomer with stronger reactivity and lower melting point, while fumaric acid is a trans isomer, more stable and has a higher melting point.

Key Differences

Maleic acid has a cis configuration, where both carboxylic acid groups are on the same side of the double bond, leading to a less stable structure. Fumaric acid, with its trans configuration, places these groups on opposite sides, contributing to greater stability.
The cis arrangement in maleic acid results in higher reactivity due to the closer proximity of its carboxylic groups. In contrast, fumaric acid's trans configuration leads to less reactive properties, as its carboxylic groups are further apart.
Maleic acid generally has a lower melting point and is more soluble in water due to its molecular arrangement. Fumaric acid, on the other hand, has a higher melting point and is less soluble, attributed to its trans structure.
In its solid form, maleic acid tends to be less stable and can easily be converted into fumaric acid. Fumaric acid remains more stable in its solid form and does not readily convert to its cis counterpart.
Maleic acid is often used in polymerization and as an additive in foods, leveraging its higher reactivity. Fumaric acid finds its use in food preservation and as an acidulant, owing to its stability and less reactive nature.

Comparison Chart


Cis isomer
Trans isomer


Less stable
More stable


Higher due to proximity of groups

Melting Point



Polymerization, food additive
Food preservation, acidulant

Maleic Acid and Fumaric Acid Definitions

Maleic Acid

An organic compound derived from butenedioic acid.
Maleic acid is converted into fumaric acid when heated.

Fumaric Acid

A dicarboxylic acid with trans configuration.
Fumaric acid is added to foods to extend shelf life.

Maleic Acid

An acid used in polymer production.
Maleic acid reacts with other chemicals to form durable plastics.

Fumaric Acid

An acidulant in the food industry.
Fumaric acid is often used to add tartness to beverages.

Maleic Acid

A compound used as an additive in food.
Maleic acid can enhance the flavor of certain snacks.

Fumaric Acid

An organic compound used in food preservation.
Fumaric acid is common in dry food mixes for its preservative qualities.

Maleic Acid

A less stable isomer of butenedioic acid.
Maleic acid's reactivity makes it useful in industrial applications.

Fumaric Acid

A compound with a higher melting point than its cis counterpart.
Fumaric acid's high melting point influences its physical properties.

Maleic Acid

A dicarboxylic acid with cis configuration.
Maleic acid is used in making polyester resins.

Fumaric Acid

A more stable isomer of butenedioic acid.
Fumaric acid remains stable under various storage conditions.


What is fumaric acid?

A trans isomer of butenedioic acid, commonly used as a food preservative.

What makes fumaric acid more stable?

Its trans configuration leads to greater stability.

In what applications is maleic acid used?

In polymerization, as a food additive, and in pharmaceuticals.

How does maleic acid's structure affect its properties?

Its cis configuration makes it less stable and more reactive.

What is the melting point of fumaric acid?

Higher than maleic acid, contributing to its physical stability.

How soluble is fumaric acid in water?

It is less soluble due to its molecular structure.

What is maleic acid?

It's a cis isomer of butenedioic acid, used in various industrial applications.

What are the uses of fumaric acid?

Mainly in food preservation and as an acidulant in beverages.

Is fumaric acid convertible to maleic acid?

No, fumaric acid does not easily convert to maleic acid.

Why is fumaric acid used in food preservation?

Its stability and acidic nature help prolong shelf life.

What is the impact of maleic acid in the food industry?

It's used as an additive to enhance flavors and textures.

What is the industrial production method for fumaric acid?

Mostly through catalytic isomerization of maleic acid.

Can maleic acid be converted into fumaric acid?

Yes, through heating or ultraviolet irradiation.

What is the melting point of maleic acid?

It has a lower melting point compared to fumaric acid.

Are there any health concerns with maleic acid?

In large quantities, it can be harmful, but is generally safe in regulated amounts.

Is fumaric acid safe for consumption?

Yes, when used in approved quantities, it's safe.

Can maleic acid be used in plastic manufacturing?

Yes, particularly in making unsaturated polyester resins.

Is fumaric acid involved in plastic production?

It's less common, but can be used in certain resin formulations.

How is maleic acid produced industrially?

Typically from benzene or butane through various chemical processes.

Is maleic acid soluble in water?

Yes, it's more soluble than fumaric acid.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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