Bismuth bismuth isooctanoate
Organic bismuth catalysts are dominated by bismuth carboxylate, especially bismuth isooctanoate.
Bismuth octanoate, also known as bismuth tris (2-ethylhexanoic acid).
English name: bismuth octote; bismuth tris (2-ethylhexanoate) and so on.
The molecular formula of bismuth octanoate is C24H45BiO6, molecular weight is 638.6, CAS number is 67874-71-9, EINECS number is 267-499-7.
Structural formula: Bi[OCOCH(C2H5)C4H9]3.
Physical and Chemical Properties
Brownish yellow viscous liquid, relative density (25℃) is 1.28~1.34, viscosity (25℃) is not more than 3Pa.s.
The Shepherd Chemical Company’s 28% bismuth isooctanoate product has a bismuth content of 27.7%～28.3%, and the nonvolatile fraction (105℃, 3h) is ≧85%.
The organic bismuth catalysts of The Shepherd Chemical Company are as follows.
Among them, BiCAT 8118 and BiCAT 8108 can be used in almost all kinds of polyurethane materials, BiCAT 8124 is recommended to be used in PU adhesives and elastomers, BiCAT 8106 is recommended to be used in adhesives and sealants, and BiCAT 8210 is recommended to be used in coatings and adhesives.
(Strem Chemicals ,Inc.) produced by the United States Strem Chemicals Limited (Strem Chemicals ,Inc.) to solvent oil as a solvent bismuth isooctanoate 72% concentration of products in Bi content of about 28%; xylene as a solvent for the concentration of 70% to 75% of the product, Bi content of about 24%.
The bismuth isooctanoate of Shenyang Applied Technology Experimental Factory is a yellow-brown liquid with 4% Bi content. Bismuth isooctanoate from another company in China is a yellow-brown liquid with solvent oil or xylene as solvent, and the bismuth content is 4%.
Characteristics and Uses
It can be used as paint drying agent, lubricating oil additive and polyurethane room temperature catalyst. Organic bismuth catalysts are environmentally friendly substitutes for organic mercury, organic lead and other toxic heavy metal catalysts, bismuth isooctanoate has very similar technical properties with organic lead, and can be used as a substitute material for lead drying agent, with better selectivity to NCO/OH group, avoiding NCO side reaction and reducing CO2 generation; bismuth compounds have better hydrolysis resistance stability than tin compounds, reducing the reactivity selectivity with water; bismuth isoctanoate is also used as a replacement material for lead drying agent, and can be used as a substitute material for lead drying agent in water-based PU dispersions. Water-based PU dispersion, reduce the side reaction between water and NCO group, can improve the drying performance of the coating in poor climatic conditions, especially in the harsh conditions of high air humidity, made of end-products with better mechanical properties; in the one-component polyurethane system, to play a role in unsealing, not to promote the reaction between NCO and water. However, the catalytic activity is lower in some systems. Bismuth-zinc combinations have a synergistic effect, allowing flexibility in formulation and production. It can be used alone or in combination with amines or other organometallic compounds.
Bismuth carboxylate catalyzes the reaction between aliphatic isocyanate and polyether secondary hydroxyl group even better than primary hydroxyl group. Under the catalytic effect of bismuth carboxylate, polyol containing β-hydroxyalkyl ester, urethane ester and ether group reacts with isocyanate faster than hydroxyl group with no positional resistance.
The high price of organic bismuth inhibits its wide application.
