Aluminum tri-isopropoxide

Commercial end functional polymers have been converted to alkoxyamincs and used to prepare PKO-Worri-PS.040 The hydroxyl group of alkoxyamine 284 was used to initiate ring-opening polymerization of caprolactonc catalyzed by aluminum tris(isopropoxide) and the product subsequently was used to initiate S polymerization by NMP thus forming polycaprolactone-Wodr- P8.641 The alternate strategy of forming PS by NMP and using the hydroxyl chain end of the product to initiate polymerization of caprolactonc was also used. 

ROP initiated with aluminum tri-isopropoxide has been extensively investigated by several research groups [41,44,60-64] since it yields well-defined polymers... 

The thermal stability of PLAs depends on the molecular modifications, additives, residual initiators, catalysts, monomers, and water content. The thermal stabiUty of PLLA synthesized using aluminum tri(isopropoxide) as an initiator is higher than that synthesized using tin(II) bis(2-ethyUiexanoate) [156]. In addition, Jamshidi et al. found that the thermal stability of PLLA synthesized using tin(II) bis(2-ethylhexanoate) increases when the terminal carboxyl group is acetylated and that residual monomers enhance the thermal degradation of PLLA [157]. 

To demonstrate the use of TBE as an initiator for the living ROP of cyclic esters (e.g., e-caprolactone, CE), aluminum tris(isopropoxide), Al(0 Pr)3, can be reacted with 4 equiv of TBE and then added to a solution of CL in toluene and polymerization conducted at room temperature for 1 h (Hawker et al., 1998) to obtain poly(caprolactone) (PCL) derivatives (P15-III) with molecular weights similar to theoretical molecular weights and low polydispersities. [Instead of Al(0 Pr)3, triethylaluminum (EtsAl) can also be added at room temperature so as to obtain the activated alkoxide derivative to catalyze the ROP of CL.]... 

Acetone, cyclohexanone, benzophenone, cinnamaldehyde, and other carbonyl compounds are hydrogen acceptors in the Oppenauer oxidation of alcohols to carbonyl compounds. The reaction is catalyzed by Raney nickel [961], aluminum alkoxides [962], tris(isopropoxide), or tris(tert-bu-toxide) as bases soluble in organic solvents [963, 964]. These dehydrogenations of alcohols to aldehydes and ketones require refluxing or distillations and have given way to dimethyl sulfoxide oxidations, which take place at room temperature. 

For an Al-Si-TUD-1, the aluminum source can be aluminum isopropoxide, aluminum tri-sec-butoxide, or another organoalumina species that forms a monomeric A1 as an intermediate component. 

The A-B di-block copolymer of -CL and oxepan-2,7-dione has been synthesized using aluminum isopropoxide as initiator [114] (Scheme 16). In order to prepare the ABA tri-block copolymer, a difunctional initiator [Et2AlO(CH2)4OAlEt2] was used to polymerize B followed by the addition of monomer A. However, the rate of polymerization was lower than in the Al(0 Pr)3-initiated system. Increasing the temperature to 70 °C increased the rate but a broadening of MWD was observed due to intramolecular back-biting reactions and intermolecular transesterification reactions. The addition of 1 equiv. of pyridine with respect to Al increased the polymerization rate and reduced the MWD from 1.95 to 1.25 [95]. 

Aluminum isopropoxide has been used for the preparation of block copolyesters [147, 148]. Tri-block poly(e-CL-b-DXO-e-CL) was prepared by the sequential addition of different monomers to a living polymerization system initiated with aluminum isopropoxide in THF or toluene solution [95]. An alternative route for the preparation of the tri-block copolymer was to react the diblock poly(e-CL-b-DXO) containing an -OH functionality at the chain end using a difunctional coupling agent such as isocyanate or acid chloride (Scheme 18). However, the molecular weights were low and full conversion of monomers was not achieved. 

Similarly, tris-isopropylboron also undergoes P-hydride elimination. Decomposition of aluminum isopropoxide thermally produces acetone by P-hydride elimination [Eq. (6.85)] ... 

Using aluminum isopropoxide as the reducing agent under thermodynamically controlled conditions (84.5 °C, 22 h), 2-(l-cyclohexenyl)butanone is converted to the more stable tram-2-(l-cyclohexenyl)cyclobutanol whereas the d.v-alcohol (80%) is obtained using the sterically more demanding boron reagent, potassium [hydrido-tris(l-methylpropyl)boranate]142. 

Schubert, U., et al. (1999). Controlled polymerization of methyl methacrylate and ethyl acrylate using tris(4,4 -dimethyl-2,2 -bipyridine)copper(II) hexafluorophosphate complexes and aluminum isopropoxide. Polym. Bull., 43(4-5) 319-326. 

C36H30AI2, Di-/x-phenyl-bis diphenylaluminum), 38B, 705 C36H6oInN9Sc, Tris(tetraethylammonium) tris-(1,2-dicyanoethylene-1,2-dithiolato)indate(lII), 37B, 640 C3eHsnAlftOi2f Aluminum isopropoxide tetramer, 45B, 793 C3bH3oO T12, Di M 2-hydroxycyclohepta-2,4,6-trien-1-onato-bis[di-phenylthalliumdlD], 46B, 726... 

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