Butyltin chloride dihydroxide

Butyltin chloride dihydroxide (CAS 13355-96-9) is an organotin compound commercially available under trade names including Fascat 4101 and PC 4101, and referenced in literature as NSC 323990 and butylchlorostannanediol. It carries no assigned E-code and is classified under organometallic compounds with HS code 29319000.

In polyurethane and silicone formulations, it functions as a condensation catalyst, accelerating cross-linking reactions between hydroxyl and isocyanate or silanol groups to control cure rate and network density. It is also employed in PVC stabilisation systems, where the tin centre coordinates with degradation intermediates to inhibit thermal dehydrochlorination during processing.

Butyltin chloride dihydroxide is supplied as a solid and is subject to REACH registration requirements within the European Economic Area. Procurement teams should confirm supplier SDS documentation and substance authorisation status, as organotin compounds face ongoing regulatory scrutiny under REACH Annex XIV candidate substance evaluations.