Bifunctional polyols

The resulting phosphonate polyol (18.17) is a bifunctional polyol having one hydroxyl group and one secondary amino group. 

Their odors are ammoniacal to varying degrees, with monoethanolamine being the most marked. The ethanolamines are hygroscopic and miscible with water, most alcohols, and polyols. They and their aqueous solutions are alkaline. Being bifunctional, ethanolamines react with acids to form esters or salts, and most of their industrial applications are dependent to some degree on these features. 

Rychnovsky and his group have recently developed new synthetic methods that lead to the total syntheses of the polyene macrolides roxaticin [2], roflamycoin [3], and filipin III [4]. The polyol chains of all three natural products were constructed by iterative, stereoselective alkylation of lithiated cyanohydrin acetonides and subsequent reductive decyanation, illustrated here by the synthesis of the polyol framework of filipin III (1) (Scheme I). The bifunctional cyanohydrin acetonide 2, prepared by ruthenium/BINAP catalyzed enantioselective hydrogenation of the corresponding ) -keto ester (BINAP = [ 1,1 -binaphthyl]-2,2 -diylbis(diphenylphosphane)), is deprotonated with LiNEt2 and alkylated with 2-benzyloxy-l-iodoethane. The alkylation product 3 is converted by a Finkelstein reaction into the iodide 4, which is used to alkylate a second... 

Some of the most familiar reactions falling into the polycondensation class are those leading to polyamides derived from dicarboxylic acids and diamines, polyesters from glycols and dicarboxylic acids, polyurethanes from polyols and polyisocyanates, and polyureas from diamines and diisocyanates. Similar polymer formations utilizing bifunctional acid chlorides with polyols or polyamines also fall into this class. The condensations of aldehydes or ketones with a variety of active hydrogen compounds such as phenols and diamines are in this group. Some of the less familar polycondensation reactions include the formation of polyethers from bifunctional halogen compounds and the sodium salts of bis-phenols, and the addition of bis-thiols to diolefins under certain conditions. 

The modification of a filler surface with isocyanates is a simple process which involves the reaction of hydroxyl groups on the filler surface with monomeric isocyanate. 2,4-toluene diisocyanate or hexamethylene diisocyanate are commonly used. Since isocyanates are bifunctional they can be further reacted with polyols to form a coating on the surface or they can be used for the reinforcement of polyurethane. A strong covalent bonding can be verified by controlled extraction with the solvent. Bound material will not be removed from the fillefs surface. 

The transamidation reactions, usually with diethanolamine, are frequently used to obtain diethanolamides of fatty acids (well known as nonionic surfactants [51-57]). Fatty acid diethanolamides are sometimes used together with other polyols, to obtain rigid PU foams. The fatty acid diethanolamides are bifunctional compounds and improve the compatibility of various polyolic systems very much, with pentanes used as blowing agents for rigid PU foams (reaction 17.15). 

A multistep reaction, polyaddition, is a polyreaction of at least two bifunctional or higher functional compounds. Polyaddition can result in either linear polymers (thermoplastics) or cross-linked plastics (duroplastics), depending on the specific functionality. Cross-linked products are obtained by means of a reaction of a bifunctional reactant with a trifunctional one. The more polyfunctional the reactant, the more closely meshed the cross-linking will be. That is why the polyols in polyurethane or epoxy resin production are frequently replaced by polyesters and polyethers containing large numbers of OH groups. Polyaddition, like polycondensation, is a multistep reaction. Fig. 4. Important polyadducts include linear and cross-linked polyurethanes as well as epoxy resins (see [2]). 

In addition to the oxidative scission of 1,2-diols, the reaction can be extended to related 1,2-bifunctional compounds such as oxiranes, 1,2-dicarbonyl compounds, 2-hydroxy aldehydes, ketones and acids, a-amino alcohols, 1,2-diamines and also to polyols. LTA cleaves a-hydroxy acids much more readily than do periodates and both reagents oxidize 2-hydroxy aldehydes and 1,2-dicarbonyl compounds relatively slowly. - Only periodic acid in water reacts with oxiranes via the corresponding diols. 

Using this technique, a large variety of polyurethanes have been prepared from different vegetable oils. Natural polyols like castor oil (generally trifunctional) are directly reacted with diisocyanates to obtain branched polyurethanes, although it is difficult to control the reactivity. However, bifunctional castor oil can be polymerised with diisocyanates in the presence of suitable chain extenders and catalysts to produce polyurethanes in a more controlled manner (Fig. 6.4). A castor oil polyol-based polyurethane network can also be prepared from epoxy terminated polyurethane pre-polymer with 1,6-hexamethylene diamine. Epoxy terminated pre-polymer is obtained by the reaction of glycidol and isocyanate terminated polyurethane pre-polymer of castor oil polyol, poly(ethylene glycol) (PEG) and 1,6-hexamethylene diisocyanate. ... 

Lactide and y-caprolactone are copolymerized in the presence of a multifunctional polyol. For example, a diol such as ethylene glycol, may be included to produce a bifunctional hydroxyl terminated polymer, or a triol, such as trimethylolpropane, may be used to produce a trifunctional pol mier hydroxyl terminated polymer. 

Polymers from hydroxy-substituted fatty acids or esters, derived from fats and oils and bifunctional compounds, have been reported [277]. The fat- and glyceridic oil-derived monomers used represent an inexpensive and readily obtainable monomer source for the preparation of condensation polymers from hydroxy- or amino-substituted fatty acids (e.g. 12-hydroxystearic acid) with difunctional compounds (e.g. diamines, polyamines, amino alcohols, diols, polyols, diacid chlorides, diisocyanates, phosgene, etc.). 

The formation of 2,3-dihydro-3,4-dihydroxy-5-acetyIfuran (48), a flavour component in baking, in the reaction between D-fructose and p-alanine has been reported." Anionic ruthenium iodocaibonyl complexes acted as dehydroxylation catalysts of C3 - Cs polyols and C sugars in aqueous solution, due to their bifunctional nature (acidity and hydrogenation ability). By exposure to [Ru(CO)3l3] in the presence of CO and Hj, glucose, fructose, and xylitol have been transformed to yvalerolactone (49), in up to 40% yield, via levulinic acid (fcumed well known acid-catalysed dehydration and internal oxidation-reduction reactions)."... 

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