Aminic polyols

Aminic polyols are low molecular weight adducts of propylene oxide (PO) [and/or ethylene oxide (EO)] made from aliphatic or aromatic polyamines such as ethylenediamine (EDA), diethylene triamine (DETA) [1, 2], ortho-toluene diamine (o-TDA) [3, 4] or diphenylmethanediamine (MDA) [2, 5, 6]. Because these starters are liquid at room temperature (EDA, DETA) or low melting point solids (o-TDA, MDA), they are alkoxylated in the absence of solvents. 

As a general rule, all the aminic polyols are much more reactive in the reaction with the aromatic isocyanates than the polyether polyols for rigid polyurethane (PU) foams initiated 

By the addition of a low steric hindrance amine (dimethylaminoethanol, dimethycyclohexylamine) or of KOH, to an aminic polyol, having hydroxypropyl groups, the extension of the chains with PO units is possible. 

For example EDA, with 4 mols of PO, is a well known crosslinking agent but has a high viscosity, around 50,000 mPa-s, at 25 °C (reaction 14.2). 

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Uses Preparation of propylene and dipropylene glycols, poly (propylene oxide), lubricants, oil demulsifiers, surfactants, isopropanol amines, polyols for urethane foams solvent soil sterilant fumigant. 

Chiral intermediates (e.g., non-proteinogenic amino acids, alcohols, amines, polyols, aminoalcohols, and acids)... 

Organic acids Amines Polyols Alcohols Esters Ketones Aldehydes Ethers Aromatics Olefins... 

Use Manufacture of polyamides, epoxy curing agents, carbinols, and amine polyols. 

Polymer polyols (filled polyols) 2. Aminic polyols... 

In order to increase the self-catalytic activity, high MW aminic polyols were created based on polyamines having one or two nitrogen atoms and low steric hindrance methyl groups (-N-CH3 groups), such as [149-151] ... 

The creation of the autocatalytic high MW aminic polyols based on N-methyl substituted poly amines, represents an important development in the area of poly ether polyols for low-fogging flexible PU foams. The VORANOL VORACTIV polyols developed by DOW represent a revolutionary group of autocatalytic polyols with reduced volatile organic compounds (VOC) emissions in PU products, especially in high resilience foams for bedding and automotive seating [149, 150]. 

Aminic polyols (aliphatic or aromatic) are a group of very reactive polyols with the structure of alkanolamines. The high reactivity is conferred by the self catalytic effect of tertiary nitrogen from the aminic polyol structure, in the reaction of hydroxyl groups with the -NCO groups (see Chapter 14). 

Aromatic amines such as o-TDA and MDA, give useless aminic polyols because of the high viscosities resulting from the direct propoxylation. 

Thus, aminic polyols of lower viscosities are obtained by the following three methods ... 

It was observed experimentally that by increasing the number of PO units per chain derived from one hydroxyl group there are obtained not only lower hydroxyl numbers but the viscosities of the resulting aminic polyols decrease significantly. The extension of the chains with PO is possible only after the addition of a catalyst, such as KOH, NaOH, low hindered tertiary amines or imidazoles. Utilisation of KOH and NaOH as catalysts needs a purification step. Using a low hindered amine as catalyst (trimethylamine, dimethyethanolamine, dimethylcyclohexylamine) the resulting polyols do not need any purification. 

Thus, by the propoxylation of DETA with around 8-10 mols of PO/mol of DETA, by using dimethylethanolamine as catalyst, aminic polyols of low hydroxyl number (390-420 mg KOH/g) are obtained, with low viscosity of around 6,000-9,000 mPa-s, at 25 °C [1,10,11] ... 

By the reaction of 4-5 mols of EO with one mol of DETA, followed by a catalysed propoxylation step, it is possible to obtain aminic polyols with a functionality of 5 OH groups/mol with a high hydroxyl number and convenient low viscosities (equation 14.5). 

The DETA-based aminic polyols are synthesised by first adding 4 mols of PO and, in the second step, adding several units of EO without any other catalyst (self catalysis). The addition of EO to the hydroxyl groups formed, being catalysed by the tertiary aminic nitrogen from the aminic polyol structure resulting from propoxylation (reactions 14.6) [11, 12]. 

By propoxylation of o-TDA with 4 PO mols, without any catalyst, an extremely viscous aminic polyol is obtained, of around 650,000 mPa-s at 25 °C (reaction 14.7). 

The same strong effect on the viscosity decrease was observed by the introduction of an internal poly [EO] block in the case of synthesis of aromatic aminic polyols derived from methylenedianiline (MDA), a precursor of diphenylmethane diisocyanate (MDI) [2, 5, 6] ... 

This method of viscosity decrease by introduction of internal EO units is very efficient for reusing wastes resulting from MDA fabrication, which have superior oligomers with 3, 4 or 5 aromatic nuclei (reaction 14.9). Propoxylation of these MDA wastes gives extremely viscous aminic polyols [2]. 

Highly aromatic and high functionality aminic polyols, of very convenient viscosities (15,000-25,000 mPa-s at 25 °C) are obtained. Similar effects of viscosity decrease were obtained by using as monomers a mixture of PO with EO (15-25% EO). 

A special aromatic aminic polyol was obtained by propoxylation or ethoxylation of aniline [7]. These diols were used sometimes as chain extenders in elastomers and in coatings. The disadvantage of these aniline-based diols is the fact that at a ratio of 2 mols of alkylene oxide (PO, especially EO) they become solid at room temperature, by crystallisation ... 

The third method to decrease the viscosity of aminic polyols is the alkoxylation of a mixture between a polyamine (which leads to very viscous polyols) with a monoamine, such as monoethanolamine, diethanolamine, diisopropanolamine or monoisopropanolamine, (which lead to fluid polyols). The quantity of monoamine is calculated so as not to affect markedly the functionality of the final aminic polyol. 

The resulting mixtures of aminic polyols (4.10) are excellent crosslinkers for rigid PU foams and other PU products. The aminic polyols, due to their intrinsic high reactivity are used especially in rigid spray PU foams. 

The Mannich polyols described are aromatic aminic polyols, the aromatic rings have a real contribution in improving the physico-mechanical, thermal and fire proofing properties of the resulting rigid polyurethane (PU) foams. The Mannich bases, for example the Mannich base resulting from one mol of nonyl-phenol, 2 mols of formaldehyde and 2 mols of... 

By the hydrolysis of a flexible foam based on toluene diisocyanate (TDI) one obtains toluene diamine (2,4 and 2,6 isomers), the polyether triol and, of course, carbon dioxide. The difficulty of the process is the separation of the amine. The amine may be used for TDI synthesis (after a previous purification), or be transformed into a valuable rigid polyol (aminic polyol) by alkoxylation with PO and EO. 

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