Reaxis®  C248LC - Dibutyltin Oxide

REAXIS® C248LC (Dibutyltin Oxide-Low Chloride) is a dialkyl organotin typically used as a catalyst in E-coat formulations and esterifications. Commonly referred to as DBTO or Dibutyloxotin, REAXIS® C248LC is characterized by a high tin content (~ 48%), low chloride content, controlled particle size distribution and an oxide ligand, all of which impart both high reactivity and high-temperature stability.  REAXIS® C248LC is supplied as a solid and can be supplied as a stable liquid with suitable diluents such as plasticizers and silanes. Related liquid-grade versions include REAXIS® C248D, which includes a plasticizer and a relatively high tin content, REAXIS® C248DP, which contains a plasticizer and lower tin content, REAXIS® C248DN, which also contains a plasticizer but has a lower overall tin volume, REAXIS® C248T, which contains a silane complex, and REAXIS® C248VM, which is another variant of our DBTO and silane compound. These liquid versions are used as catalysts for silicone condensation reactions. REAXIS® C248 is the standard solid-grade version. 

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Technical Information

  • Product Category Organotin

  • Chemical Name Dibutyltin Oxide

  • CAS Number 818-08-6

Typical Specifications

Parameter Range
Tin Content (%) 47.0 Min
Chloride (%) 500 Max
Moisture (%) 0.5 Max
Fe (ppm) 10 Max

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® C248LC is are used in electro-coat (E-coat) applications, where it is preferred due to the more controlled particle size and lower chlorides. REAXISsup>® C248LC is used as homogenous catalyst for fatty acid -based saturated and unsaturated monomeric and polymeric esters. REAXIS® C248LC can be used as a transesterification catalyst and is this used in the synthesis of alkyd resins. In its plasticizer and silane liquid forms, DBTO is a good silicone condensation catalyst for adhesive, sealant, and coatings formulations, especially those formulations using silane terminated polymers (STPs). Alternative catalysts for esterification reactions include REAXIS® C220 (Monobutyltin Tris-(Ethylhexanaote)), REAXIS® C160 (Stannous Oxalate) and REAXIS® C129 (Stannous Octoate).


REAXIS® C248LC has a few characteristics that make it a suitable catalyst for a wide range of high-temperature esterification reactions. These include a high active tin content, dialkyl content and the presence of an oxide ligand. These characteristics result in a tin catalyst with good compatibility in a wide range of ester formulations, high reactivity leading to lower reaction times and the synthesis of low color end products, stability at typical reaction temperatures (180-230°C), and hydrolytic stability in the presence of water generated during esterification.

Package & Storage

  • 20kg (44lb) pails

REAXIS® C248LC should be stored in the original packaging at moderate temperatures. The container should be closed tightly after each use to maximize shelf life.

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

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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