Alkylated amino resins production

In general, conditions for the first part of the reaction are selected to favor the formation of methylol compounds. After addition of the reactants, the conditions may be adjusted to control the polymerization. The reaction may be stopped to give a stable symp. This could be an adhesive or laminating resin and might be blended with filler to make a molding compound (see also Laminates Reinforced PLASTICS). It might also be an intermediate for the manufacture of a more complicated product, such as an alkylated amino resin, for use with other polymers in coatings. 

Properties. Alkylated amino resins can be classified into two general classes (1) polymeric, partially alkylated resins which have a lower solids content and (2) the more monomeric, fully and partially alkylated products which have a higher solids content. 

Some other polymers such as aromatic and aliphatic hydrocarbon resins, high MW alkylated amino resins, polyvinyl ethers and polyvinyl butyrals are utilized for the purpose of enhancing leveling. They are not marketed as leveling agents but are used in specialty products. 

Over half of the remaining market for products used in the processing of rubber is made up of antioxidants, antiozonants and stabilizers, either amino compounds or phenols. Aniline is used to manufacture vulcanization accelerators, antioxidants and antidegradants. Of the latter, several are A-substituted derivatives of p-phenylenediamine and octyl dipheny-lamine. Diphenylamines terminate free-radical reactions by donating the amino hydrogen, and are used to protect a wide range of polymers and elastomers. Many synthetic rubbers incorporate alkylated diphenylamine antioxidants. Other antioxidants include aryl amine resinous products from, e.g. condensation of aniline and acetone in the presence of... 

Production. Although the patent literature cites many other amino and amide compounds, only urea, melamine, benzoguanamine, acrylamide, and glycoluril have found a market position as starting materials for the production of amino resins. Formaldehyde is the only aldehyde used on a commercial scale. Methanol, butanol, and isobutanol are mainly employed as alkylating alcohols. 

Some important compounds used in synthesis of amino resins are shown in Figure 2.22. Synthesis of amino resins for surface coatings typically involves two steps. In the first step, known as a methylo-lation reaction (Figure 2.23), the amino compound is reacted with formaldehyde to yield a methylolated intermediate. In the second step, known as an alkylation/etherification reaction (Figure 2.23), the methylolated intermediate is reacted with an aicohol to produce an aikyi ether of methyioi groups. While methylol formation (step 1) is possibie over the entire pH range, this reaction is generally carried out under basic conditions to obtain usefui products. 

The storage stability of pre-condensates based on phenol-formaldehyde usually poses no problem. This is not the case with amino-resin pre-condensates. Technically significant are only the reaction products of urea, urea derivatives, and melamine with formaldehyde. The hydroxyl alkyl amines formed in an addition reaction... 

Normally the reaction Is useful for the conversion of alkyl halides to primary amines without concomitant formation of secondary amines.29 Treatment of polymer 17 with hexamethylenetetramine in a mixture of ethanol/THF afforded an insoluble resin. Using diazabicyclooctane (DABCO), we demonstrated that the reaction could be limited to attack by a single nitrogen in a multifunctional amine, so we did not anticipate crosslinking via bis-quat salt formation. Hydrolysis of 2 with anhydrous HC1 in ethanol generated free amino groups as evidenced by a positive ninhydrin test, but quantitative hydrolysis could not be achieved and the product remained insoluble. One would have expected a simple bis-quat to hydrolyse and open the crosslinked structure. 

Several syntheses of l,3-dioxoperhydropyrrolo[l,2-c]imidazoles have been developed using different strategies. a-Substituted bicyclic proline hydantoins were prepared by alkylation of aldimines 135 of resin-bound amino acids with a,tu-dihaloalkanes and intramolecular displacement of the halide to generate cr-substituted prolines 136 and homologs (Scheme 18). After formation of resin-bound ureas 137 by reaction of these sterically hindered secondary amines with isocyanates, base-catalyzed cyclization/cleavage yielded the desired hydantoin products <2005TL3131>. 

A problem with the chromatographic determination of cysteic acid is that there is almost no retention of cysteic acid. For both reversed-phase HPLC and ion-exchange amino acid analyzers (usually employing cation-exchange resins), cysteic acid is essentially eluted within or near the void volume of the column. This makes it more susceptible to unknown chromatographic interferences from various matrices. When cysteine is alkylated by 3-bromopropylamine, the product (S-3-aminopropylcysteine) looks very similar to lysine in structure. Hale et al. (90) show that this alkylated species affords excellent chromatographic separation on four different commercially available amino acid analysis systems and that, indeed, it does elute very near lysine in each case (see Fig. 4). 

Aube and co-workers have found that enolizable ketones react with benzyl azide in triflic acid to yield /V-(phenylamino)-methylated products [Eq. (5.354)]. The transformation is an aza-Mannich reaction interpreted with the involvement of the Mannich reagent A -phenyl iminium ion 295 formed in situ in a Schmidt rearrangement. Cyclic tertiary alcohols react with alkyl azides in triflic acid to yield N-alkylamines (296, 297)983 [Eq. (5.355)]. The Schmidt rearrangement was used to transform Merrifield resin into amino-polystyrene resin by reacting the azido derivative in excess triflic acid (CH2CI2, 0°C).984... 

The major diastereomer 95 could be obtained in optically pure form by silica gel chromatography. The absolute configuration of the amination product was dictated by the choice of the chiral diamine, and correlated with previous results in asymmetric a-alkylation. Furthermore, the major diastereomer 95 was converted to the corresponding (ft)-a-aminoethyl phosphonic acid 96 by sequential treatment with (i) TFA, CH2C12,0 °C (ii) 1 N HC1 and (iii) H2, Pt02,70 psi, followed by Dowex 50 (H+) resin chromatography in 73 % overall yield. Optical rotation of the a-amino phosphonic acid 96 allowed the confirmation of its optical purity (> 98 %) and of its absolute configuration. 

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