Calumet Specialty Products Partners has entered into a definitive agreement to purchase Royal Purple for approximately $335m.
Royal Purple manufactures high-performance lubricants for automotive, marine and other industrial applications.
Calumet will fund the acquisition through a mix of cash on hand, loans from its secured credit facility and other long-term debt financing if possible.
Bill Grube, Calumet chief executive officer, said Royal Purple has a specialty product line of lubricants serving the industrial and consumer automotive markets.
"They also have a very experienced and dedicated workforce and we are looking forward to working with them," Grube added.
Lee Culbertson, Royal Purple president and chief executive officer, said: "We believe Calumet shares Royal Purple's vision and commitment to excellence and will greatly assist in our continued growth."
The transaction is expected to close by the middle of July 2012 and is subject to customary closing conditions and regulatory approval.
Pursuant to the agreement, Calumet will acquire 100% membership interests of Royal Purple as a limited liability company at the closing.