Tin octoate

A typical condensation system involves the reaction of a silanol-terminated polydimethylsiloxane with a multi-functional organosilicon cross-linking agent such as Si(RO)4 Figure 29.8). Pot life will vary from a few minutes to several hours, depending on the catalysts used and the ambient conditions. Typical catalysts include tin octoate and dibutyl tin dilaurate. 

Figure 7. Surface concentration (Cs) of the hydroxyl groups phenylurethanated with and without tin octoate for cellulose films (O) Visking without catalyst (0) cellophane with tin octoate...

It is also seen that when phenylurethanation is carried out at 30°C with the use of tin octoate as catalyst, the reaction proceeds with a higher rate than that without catalyst in spite of lower temperature, but the products show a similar saturated level of urethanation. 

Currently, tin(II) bis-(2-ethyUiexanoate), also referred as tin octoate, is the most widely used catalyst for the ROP of lactones. This popularity stems from its acceptance by the American Food and Drug Administration (FDA) for the formulation of polymer coatings in contact with food. Moreover, tin(II) bis-(2-ethyUiexanoate) is less sensitivity towards water and other protic impurities than aluminum alkoxides, which facilitates its use in the laboratory and in industry. 

The second approach is based on the polymerization of lactones bearing functionalized substituents. A set of lactones bearing chloride [124-126], bromide [127, 128], iodide [129], alkene [130-134], or alkyne [135] were synthesized and (co)polymerized by tin octoate, tin(IV), and aluminum alkoxides (Fig. 29). 

For selectiveness of initiation of graft reactions, the use of a tin octoate (SnOct2) (or tin(II) 2-ethylhexanoate) catalyst is convenient for preparing this type of copolymers, polysaccharide-gra/f-PHAs, because the ring-opening polymerization of cyclic esters such as lactides and e-caprolactone (CL) can be initiated efficiently by hydroxo-initiators (i.e. based on hydroxyl groups) in the presence of SnOct2 [12-16], as exemplified in Scheme la. 

Thus, termination of oxazoline polymerization with potassium hydroxide gave hydroxy-terminated polymers, which in the presence of tin octoate were capable of initiating the anionic polymerization of -caprolac-tone [287] giving the corresponding block copolymer, acting as effective compatibiliser. 

Silanol-silane reaction. A is removal of H B is Si-O-Si crosslinked polymer tin octoate is the catalyst. 

The alcoholate was alternatively reacted with tin octoate to initiate the polymerization of L-lactide (LL) and produce (PS)(PEO)(PLL) star terpolymer. In another application of the method, the 1,1-diphenyl -alkylpotassium intermediate (I) was used to initiate the polymerization of MM A at —78 °C. After de-protecting and activating the hydroxyl group, the polymerization of ethylene oxide was initiated, leading to the formation of the (PS)(PMMA)(PEO) star terpolymer. If e-CL is polymerized instead of EO, then (PS)(PMMA)(Pe-CL) stars are produced. Limited characterization data were given for these stars. In all cases two of the arms grow from the star center and thus cannot be isolated and characterized. However, interesting amphiphilic structures were obtained. 

EINECS 206-108-6 2-Ethylhexanoic acid tin(2-<-) salt Metacure T-9 NSC 75857 Nuocure 28 Stannous 2-ethylhexanoate Stannous 2-ethylhexoate Stannous octoate Tin 2-ethylhexanoate Tin bis(2-ethylhexanoate) Tin diocloate Tin ethylhexanoate Tin octoate Tin(2-r) 2-ethylhexanoate Tin(ll) 2-ethylhexanoate Tin(ll) 2-ethylhexylate Tin(ll) bis(2-ethylhexanoate). Catalyst used in production of PU coatings, adhesives, and sealants uniform activity and excellent stability. Arr Products Chemicals Inc. 

Two-component RTV formulations involve separate packages for the polysiloxane and cross-linking agent. A typical two-component RTV formulation cures by reaction of silanol end groups with silicate esters in the presence of a catalyst such as tin octoate or dibutyltin dilaurate (Figure 4.38). 

It is usually obtained by ROP of e-caprolactone in the presence of metal alkoxides [aluminium isopropoxide, tin octoate] [Okada, 2002 Albertsson and Varma, 2002 Chiellini and Solaro, 1996]. It is a semi-crystalline water-soluble synthetic polymer made from... 

Lactide is produced by degradation reactions, mainly via intramolecular chain scission of the prepolymer. Lactide synthesis from a prepolymer with a DP in the range of 10-15 in the presence of various catalysts at 4-5 mbar and 190-245°C is reported by Noda and Okuyama [9]. The best performances were reported using 0.05-0.2 wt% tin catalysts and tin octoate (stannous 2-ethylhexanoate) in particular, which is widely available. The catalyst increases the rate of backbiting reactions from hydroxyl chain ends of prepolymers to form lactide molecules [9, 15]. The melt viscosity of the prepolymer increases because of the esterification reactions during the process, which results in decreased rate of mass transfer. 

Despite the fact that the metal ions enable to control the polymerisation, they also pose an important downside as the formed polymers will always contain metal residues. These metal ions might have detrimental health effects. Aluminium derivatives have already been linked to Alzheimer s disease, although this hypothesis is controversial [50], while tin octoate, despite being FDA approved, has already been shown to be cytotoxic. As tin levels often exceed 1000 ppm, the FDA has set a limit of 20 ppm for polyesters used for biomedical applications [51]. To circumvent this problem, attention has already been paid to less toxic catalysts including magnesium and calcium alkoxides. Conversely, attempts are being made to remove the catalyst residues from the polymer. 

Synonyms Sn-(ll)-ethylhexanoate Stannous 2-ethylhexanoate Stannous-2-ethylhexoate Tin octoate Tin-(ll)-octoate Empiricail CjsFIsoQiSn Formula Sn(C8H,sQ2)2... 

Poly(lactic acid)s can be synthesized by two methods (i) polyeondensation of lactic acids and (ii) ROP of LAs [1, 3, 8, 54, 55], Figure 8.3 shows the synthesis of PLLA, PDLA, and their block copolymers [11], Tin-based catalysts such as tin (II or IV) chloride and tin (II) bis-2-ethyUiexanoic acid (stannous octoate or tin octoate) were reported to effectively increase the molecular weight of the resulting PLAs up to an order of 10 and 10 g mol for polyeondensation [56,57] and ROP [58-61], respectively. Moreover, bulk polymerization in the presence of these catalysts aids in avoiding racemization and transesterification during the ROP of LA. 

Tin fluoborate Tin fluoborate (ous). See Stannous fluoroborate Tin fluoride. See Stannous fluoride Tin fiuoroborate Tin (ii) fiuoroborate Tin fiuoroborate (ous). See Stannous fiuoroborate Tin, fiuorotriphenyi. See Triphenyitin fiuoride Tin monoxide. See Stannous oxide Tinoclarite Mg-DTPA. See Pentetic acid Tin (ii) octadecanoate. See Stannous stearate Tin octoate Tin-(ii)-octoate. See Stannous octoate... 

The establishment of the equilibrium is often accelerated by acidic or basic catalysts, for example, by strong acids (p-toluenesulfonic acid), metal oxides (antimony trioxide), Lewis acids (titanium tetrabutoxide, tin acetates or tin octoates), weak acid salts of alkali metals or alkaline earth metals (acetates, benzoates), or by alcoholates. 

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