Tin -ethylhexanoate

Di(2-propenyl)-l,4-dioxane-2,5-dione (5.0 mmol), L-lactide (45.0 mmol), 20 ml of 0.01 M toluene solution of tin 2-ethylhexanoate, and 20 ml of 0.01 M toluene solution of /M-butylbenzyl alcohol were charged in a polymerization ampoule and then sealed and heated at 150°C for 1 hour. The polymer was then dissolved in chloroform, precipitated in excess methanol, filtered, and 6.55 g of product isolated containing 9 mol% 3,6-di(2-propenyl)-l,4-dioxane-2,5-dione and having an Af of 17,400Da with an Mw of 23,300 Da. 

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. 

Leenslag, J.W. and Pennings, A.J. (1987) Synthesis of high-molecular-weight poly(L-lactide) initiated with tin 2-ethylhexanoate. Makromolekulare Chemie, 188, 1809-1814. 

Among the coordination insertion catalysts, tin 2-ethylhexanoate (tin octoate, or Sn(Oct)2) is the most widely used and studied due to its ability to produce highly crystalline PLA in relatively short periods of time with high conversion and low racemization up to 180°C. It has also been approved by the United States Food and Drug Administration for food contact (16), making it ideal for many packaging applications. 

Leaded tin bronze Leaded tin bronzes Leaded yellow brass Leaded zinc oxide Lead 2-ethylhexanoate... 

Poly(L-lactide) microspheres were obtained from polymers synthesized as described by Duda and Penczek [13] in polymerization of Lc initiated with tin(ll) 2-ethylhexanoate and carried out in 1,4-dioxane. Microspheres were prepared from a polymer with = 9,300 and M /M = 1.06. 

The mechanism of the tin(II) bis-(2-ethylhexanoate)-mediated ROP of lactones remained a matter of controversy for many years, and many different mechanisms were proposed. Indeed, tin(II) bis-(2-ethylhexanoate) is not made up of alkoxides but of carboxylates, known as poor initiators for the ROP of lactones. In 1998, Penczek and coworkers made a major contribution in this field. They reported that, if the polymerization is carried out in THF at 80 °C, then tin(II) bis-(2-ethylhexanoate) is converted in situ into a new tin alkoxide by the reaction with either an alcohol, purposely added in the reaction medium, or with any other protic impurity present in the polymerization medium (Fig. 14) [37]. Tin alkoxides formed in situ are the real initiators of the polymerization, which takes place according the usual... 

Interestingly, salts other than tin(ll) bis-(2-ethylhexanoate) such as scandium and tin trifluoromethanesulfonate [41 3], zinc octoate [44, 45], and aluminum acetyl acetonate [45] were reported to mediate the ROP of lactones. As far as scandium trifluoromethanesulfonate is concerned, the main advantage is the increase of its Lewis acidity enabling the polymerization to be carried out at low temperatures with acceptable kinetics. Later, faster kinetics were obtained by extending the process to scandium trifluoromethanesulfonimide [Sc(NTf2)3] and scandium nonafluorobutanesulfonimide [Sc(NNf2)3] and to other rare earth metal catalysts (metal=Tm, Sm, Nd) [46]. 

To this end, a very widely used approach is ROP initiated by polyols (at least triols) in the presence of tin(II) bis-(2-ethyUiexanoate) [155,156]. By implementing this technique, alcohols are dormant species and have to be activated by reaction with tin(II) bis-(2-ethylhexanoate) into tin alkoxides to initiate or to propagate the polymerization. The alcohols are thus not activated at the same time and no side-reactions between them are observed. Besides, it is more appropriate to initiate... 

Multifunctional initiators made up of metal alkoxides rather than alcohols have been less used for the synthesis of star-shaped polyesters than have the tin (II) bis-(2-ethylhexanoate)/alcohol system. Nevertheless, Kricheldorf initiated the polymerization of sCL using a spiro-cyclic tin(IV) aUcoxide to obtain a tin-containing height-shaped polyester whose final hydrolysis resulted in the formation of a star-shaped polyester (Fig. 35) [25, 159-161]. 

A variety of anionic initiators, both ionic and covalent, have been used to polymerize lactones [Duda and Penczek, 2001 Jedlinski, 2002 Jerome and Teyssie, 1989 Penczek and Duda, 1993]. Much of the more recent activity involves the use of anionic covalent (coordination) initiators such as alkylmetal alkoxides and metal alkoxides such as R2A OR and Al(OR)3, metal carboxylates such as tin(II) 2-ethylhexanoate, metalloporpyrins (VI), and aluminox-anes such as oligomeric [A1(CH3)0] [Biela et al., 2002 Duda et al., 1990 Endo et al., 1987a,b Gross et al., 1988 Kricheldorf et al., 1990 Penczek et al., 2000a,b Sugimotoa and Inoue, 1999]. 

Tin(II) 2-ethylhexanoate is an important industrial initiator for cyclic ester polymerization [Duda and Penczek, 2001 Kricheldorf et al., 2001 Storey and Sherman, 2002]. Metal car-boxylates are useful initiators only in the presence of alcohols. The polymerization rate is very slow in the absence of alcohol, less than 1% of the rate in the presence of alcohol. The actual initiator is the metal alkoxide formed by the reaction between metal carboxylate and alcohol. 

A reactor was charged with 100 ml of toluene, 6,6-dimethyl-l,4-dioxane-2,5-dione (0.138 mol), poly(ethylene-glycol) (0.00578 mol 1000 Da), and tin(II)-2-ethyl-hexanoate (90% in 2-ethylhexanoic acid (0.141 mmol) and then refluxed for 24 hours using a Soxhlet extractor. The mixture was then cooled and concentrated. 

Frye and his co-workers have continued their tracer investigations of PVC stabilisation (67) and claim to have synthesised (68) a whole series of compounds Bu2SnY2 with labelled butyl groups, labelled tin atoms or labelled Y groups where Y = oxo-octylthioglycollate, mono-methyl-maleate, 2-ethylhexanoate or /S-mercapto-propanoate. They sought to learn a) Do any chemical reactions occur between stabiliser and polymer b) If so what are their natures c) Do the reactions contribute to polymer stabilisation ... 

To produce biodegradable poly(lactic acid-co-lysine) copolymers (for cell adhesion), it was first necessary to synthesize the monomer 3-[4-(A-benzyloxycarbonyl)aminobutyl]-6-methylmorpholine-2,5-dione (4, Scheme 4). During the final ring-closure step, a minor amount of epimerization occurs. However, the diastereomeric purity of 4 is in excess of 95%. The monomer 4 is copolymerized with L,L-lactide (3,6-dimethyl-l,4-dioxane-2,5-dione, 5) (Scheme 5) in tin(II) 2-ethylhexanoate at 100 °C for 24 hours. 

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. 

Albertsson et al. [55, 56,95, 114, 125-138] have done extensive work on the homo- and copolymerizations of lactones in bulk as well as in solutions using ROP. In bulk polymerization temperatures in the range of 100-150 °C were used while in solution polymerization, the temperature was kept low, 0 to 25 °C, to minimize side-reactions such as intra- and intermolecular transesterification reactions. Only oligomers were formed when DXO was (co)polymerized using an ionic initiator. Poly(DXO) of high molecular weight (>150,000) was obtained using tin(II) 2-ethylhexanoate [127]. 

High molecular weight poly(DXO) has been prepared at 110 °C using tin(II) 2-ethylhexanoate as catalyst [127]. Transesterification and degradation occurred above 130 °C. 

Synthetic routes include anionic, cationic, zwitterionic, and coordination polymerization. A wide range of organometallic compounds has been proven as effective initiators/catalysts for ROP of lactones Lewis acids (e.g., A1C13, BF3, and ZnCl2) [150], alkali metal compounds [160], organozinc compounds [161], tin compounds of which stannous octoate [also referred to as stannous-2-ethylhexanoate or tin(II) octoate] is the most well known [162-164], organo-acid rare earth compounds such as lanthanide complexes [165-168], and aluminum alkoxides [169]. Stannous-2-ethylhexanoate is one of the most extensively used initiators for the coordination polymerization of biomaterials, thanks to the ease of polymerization and because it has been approved by the FDA [170]. 

Morpholine-2,5-dione (l,4-oxazacyclohexane-2,5-dione) is characterised by the appearance in its molecule of both the <5-lactam and -lactone functions. The coordination polymerisation of this monomer [scheme (22)] has been reported for systems with diethylzinc [178] and tin bis(ethylhexanoate) [150] as catalysts ... 

Of the large volume of tin compounds reported in the literature, possibly only ca 100 are commercially important. The most commercially significant inorganic compounds include stannic chloride, stannic oxide, potassium stannate, sodium stannate, stannous chloride, stannous fluoride, stannous fluoroborate, stannous oxide, stannous pyrophosphate, stannous sulfate, stannous 2-ethylhexanoate, and stannous oxalate. Also important are organotins of the dimethyl tin, dibutyltin, tributyltin, dioctyltin, triphenyltin, and tricyclohexyltin families. 

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