Monobutyltin oxide

Monobutyltin oxide (CAS 51590-67-1) is an organotin compound supplied under trade names including Tegokat 256, PC 4100, ZT 4100, TMG 256, and Eurecat 8200. It carries no assigned E-code and is classified within the organometallic compounds category with the molecular formula C4H10OSn.

In polyurethane and polyester systems, monobutyltin oxide functions as a condensation catalyst, accelerating esterification and transesterification reactions by activating carbonyl groups toward nucleophilic attack. It is also used in PVC stabilisation and textile finishing processes, where it promotes cross-linking and contributes to flame retardant performance in polymer matrices.

Monobutyltin oxide is subject to REACH regulation and must be handled in accordance with applicable organotin restrictions under EU chemical legislation. Procurement teams should confirm supplier compliance documentation, including Safety Data Sheets aligned with Regulation (EC) No 1907/2006, and verify available packaging formats and grade specifications directly with the supplier.