Reaxis®  C248VM - Dibutyltin Oxide + Silane

REAXIS® C248VM (Dibutyltin Oxide + Silane) is a liquid version of dibutyltin oxide (DBTO) containing vinyltrimethoxy silane (VTMO), which  is commonly used as a catalyst for silicone chemistries.  REAXIS® C248VM contains 50% of the active tin catalyst content compared to the solid version of REAXIS® C248. Other silane grades include REAXIS® C248T (DBTO+ tetraethylortho silane/TEOS) and REAXIS® C417 (DOTO + tetrapropylortho silane/TPOS). Liquid versions of REAXIS® C248 utilizing phthalates as a non-reactive diluent include REAXIS® C248DP and REAXIS® C248DN. Other liquid grades are available upon request.

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Technical Information

  • Product Category Organotin

  • Chemical Name Dibutyltin Oxide + Silane

  • CAS Number 818-08-6

Typical Specifications

Parameter Range
Tin Content (%) 31.1 - 35.1
Color (Gardner Number) 5 Max
Density (g/ml) 1.2 - 1.4

International Regulatory Listings

  • TSCA (US) Yes

  • DSL (Canada) Yes

  • AICS (Australia) Yes

  • KECI (South Korea) Yes

  • IECSC (China) Yes

  • ENCS (Japan) Yes

  • TCSI (Taiwan) Yes

  • NZloC (New Zealand) Yes

  • PICCS (The Philippines) Yes

  • NDSL (Canada) No

  • REACH (EU) No


REAXIS® C248VM and its alternatives can be used as a homogeneous catalyst in a wide spectrum of silicone applications including adhesives, sealants, and elastomers. Silicone-based applications include: acetoxy-, ethoxy- and oxime-based Room Temperature Vulcanizing (RTV) adhesives and sealants, polyethylene crosslinked silanes (PEX), and select silane modified polymers (SMPs).


Given its high tin content, liquid form, and good compatibility with a wide range of raw materials, REAXIS® C248VM tends to be a highly reactive catalyst across a broad range of silicone formulations. In regard to silicone reactions, REAXIS® C248VM, like all tin-based catalysts, will catalyze the silanol/silane condensation reaction,acting as both a polymerization and crosslinking catalyst. REAXIS® C248VM is hydrolytically stable within typical formulation moisture levels, but this stability will break down with increasing moisture content.  

Package & Storage

  • 44 lb (20 kg) plastic pail
  • 440 lb (200kg) steel drum

REAXIS® C248VM should be stored in the original packaging at moderate temperatures. The container should be closed tightly after each use to maximize shelf life. Given the presence of a silane, hydrolytic instability could occur resulting in reduced catalytic performance.

Safety and Handling

Before use of Reaxis products please refer to the relevant Safety Data Sheet (SDS) for safety and toxicological data as well as for the information on proper transportation, storage, and use. SDSs are available by request via our web site, contacting your local representative, or emailing direct to

Hazard Classification (US SDS)

Section Hazard Class Category Hazard Statement
A.10 acute toxicity (oral) 4 H302
A.2 skin corrosion/irritation 2 H315
A.3 serious eye damage/eye irritation 1 H318
A.4S skin sensitization 1 H317
A.5 germ cell mutagenicity 2 H341
A.7 reproductive toxicity 1B H360
A.8 specific target organ toxicity - single exposure 1 H370
A.9 specific target organ toxicity - repeated exposure 1 H372
B.6 flammable liquid 2 H225

Hazard Pictograms (US SDS)


Transportation Information (US SDS)

DOT IMDG ICAO Environment Hazard
UN Number UN 1993 UN 1993 UN 1993 hazardous to the aquatic environment
UN Proper Shipping Name Flammable liquid, n.o.s. FLAMMABLE LIQUID, N.O.S. Flammable liquid, n.o.s.
Transport Class 3 3 3
Packing Group ll ll ll

Primary Composition Substance(s)

  • dibutyl tin oxide

Alternative Product(s) to Consider

This information is provided to the best of our knowledge but without obligation. Reaxis is not liable for any incorrect or missing information. This data sheet becomes invalid upon publication of a new version. Please contact us for the latest version.

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