Difference Between Acrylamide and Bisacrylamide

Main Difference – Acrylamide vs Bisacrylamide

Acrylamide and Bisacrylamide are amides. Amides are organic compounds that contain an amide group (-C(=O)NRR’). Bisacrylamide is a type of acrylamide. Majority of acrylamides are used in the manufacture of various polymers. Some additional uses of acrylamide include use as a binding and thickening agent, in cement manufacture, etc. Bisacrylamide, on the other hand, is the common name used for N,N’-methylenebisacrylamide. Bisacrylamide is mainly used as a cross-linking agent. The main difference between acrylamide and Bisacrylamide is that acrylamide has a C-N bond whereas Bisacrylamide contains an N-C-N bond.

Key Areas Covered

1. What is Acrylamide
     – Definition, Chemical Properties, Production
2. What is Bisacrylamide
     – Definition, Use as a Crosslinking Agent
3. What is the Difference Between Acrylamide and Bisacrylamide
     – Comparison of Key Differences

Key Terms: Acrylamide, Amide Group, Bisacrylamide, Cross-Linking Agent, N N’-methylenebisacrylamide, Polyacrylamide, Polymers, Prop-2-enamide

What is Acrylamide

Acrylamide is an organic compound having the chemical formula C₃H₅NO. It is an amide containing an amide group (-C(=O)NRR’). Here, acrylamide has two hydrogen atoms bonded to the nitrogen atom. The IUPAC name of this compound is prop-2-enamide (prop = three carbon atoms present, 2-enamide = amide consist of a double bond in the 2^nd carbon). Acrylamide is also called acrylic amide.

Figure 1: Acrylamide Chemical Structure

At room temperature, acrylamide is a white crystalline solid compound that is odorless. It is soluble in water and many other polar solvents. The molar mass of acrylamide is 71.08 g/mol. The melting point of acrylamide is 84.5 °C and at high temperatures, it decomposes instead of vaporization; therefore, there is no boiling point. Furthermore, acrylamide decomposes non-thermally in the presence of acids, bases, oxidizing agents and iron. This non-thermal decomposition forms ammonia. The thermal decomposition forms carbon monoxide (CO), carbon dioxide (CO₂) and oxides of nitrogen (NO_x).

Production of Acrylamide

Acrylamide can be prepared by the addition of water to acrylonitrile.

CH₂=CHCN      +     H₂O        →      CH₂=CHCONH₂

This reaction is catalyzed by reduced copper catalyst (Cu+), but the yield is poor. This should be done at high temperatures; the catalyst cannot be recycled, and unwanted polymerization reduces the yield. These drawbacks can be overcome using immobilized nitrile hydratase.

Acrylamide Polymerization

The product obtained from the polymerization of acrylamide is polyacrylamide. The repeating unit of this polymer is -CH₂CHCONH₂-. It is a network structure due to the presence of crosslinks between polyacrylamide polymer chains. The crosslinking agent used here is Bisacrylamide. Polyacrylamide is mainly used as a gel in gel electrophoresis (a technique used to separate charged molecule in mixtures).

What is Bisacrylamide

Bisacrylamide is an amide having the chemical formula C₇H₁₀N₂O₂. It is common as a cross-linking agent used in polymerization processes such as polyacrylamide production. It is the widely used cross-linking agent for protein separation applications in polyacrylamide gels. The IUPAC name of Bisacrylamide is N,N’-methylenebisacrylamide.

This structure has an N-C-N bond since it has two amide groups connected to each other. This compound is called Bisacrylamide because it is formed by the combination of two acrylamide molecules. The molar mass of this compound is 154.17 g/mol. It has two nitrogen atoms and two oxygen atoms in its chemical structure. At 365° F, Bisacrylamide melts with decomposition. It is available as a white crystalline powder.

Figure 2l: N,N’-methylenebisacrylamide

Bisacrylamide polymerizes with acrylamide to form crosslinks between polyacrylamide polymer chains. Due to this cross-linking, polyacrylamide gels have a high network structure (no individual polymer chains. All chains are connected to each other).

Difference Between Acrylamide and Bisacrylamide

Definition

Acrylamide: Acrylamide is an organic compound having the chemical formula C₃H₅NO

Bisacrylamide: Bisacrylamide is an amide having the chemical formula C₇H₁₀N₂O₂.

IUPAC Name

Acrylamide: The IUPAC name of acrylamide is prop-2-enamide.

Bisacrylamide: The IUPAC name of Bisacrylamide is N,N’-methylenebisacrylamide.

Molar Mass

Acrylamide: The molar mass of acrylamide is 71.08 g/mol.

Bisacrylamide: The molar mass of Bisacrylamide is 154.17 g/mol.

Chemical Bonding

Acrylamide: Acrylamide has a C-N bond between carbon and nitrogen.

Bisacrylamide: Bisacrylamide has a N-C-N bond between carbon and nitrogen.

Amide Group

Acrylamide: Acrylamide has one amide group.

Bisacrylamide: Bisacrylamide has two amide groups.

Melting and Boiling Point

Acrylamide: The melting point of acrylamide is 84.5 °C, and at high temperatures, it decomposes.

Bisacrylamide: At 365° F, Bisacrylamide melts with decomposition.

Water Solubility

Acrylamide: Acrylamide is water soluble.

Bisacrylamide: Bisacrylamide is slightly water soluble.

Uses

Acrylamide: Acrylamide is used as a monomer for polyacrylamide, and used as a binding and thickening agent.  

Bisacrylamide: Bisacrylamide is mainly used as a crosslinking agent in polymerization processes.

Conclusion

Both acrylamide and Bisacrylamide are amide forms. They are composed of C, H, O and N atoms. These compounds have different applications based on their chemical structures and properties. Acrylamide is the monomer used for the production of polyacrylamide polymer. Bisacrylamide is used to make crosslinks between these polyacrylamide polymer chains. The main difference between acrylamide and Bisacrylamide is that acrylamide has a C-N bond whereas Bisacrylamide contains an N-C-N bond.

Reference:

1. Preparation of acrylamide.Enzyme Technology,  Available here.
2. “Bis-Acrylamide, 2% Solution.” Bis-Acrylamide, 2% Solution – Gold Biotechnology, Available here.
3. “N,N’-Methylenebisacrylamide.” Wikipedia, Wikimedia Foundation, 18 Jan. 2018, Available here.

Image Courtesy:

1. “Acrylamide-2D-skeletal” (Public Domain) via Commons Wikimedia
2. “Methylenebisacrylamide” By Edgar181 – Own work (Public Domain) via Commons Wikimedia