Amines ethylenimine

A process for the production of ethylenimine [151 -56-4] a suspect carcinogen, by the vapor phase dehydration of monoethanol amine has been developed (128—132). By using an alkyleneamine co-feed with the alkan olamine, higher alkylene amines are made in situ (133). The catalysts are tungsten-, niobium-, or phosphate-based. 

The secondary amines used in the preparation of enamines have been primarily simple dialkylamines or cyclic amines of five- or higher-membered rings. Azetidine (4) yields a stable enamine with cyclopentanone (28). No simple enamines formed by condensation of ethylenimine (5) or a substituted ethylenimine with an aldehyde or ketone have been reported. 

Figure 1.93 2-Bromoethylamine can be used to transform a thiol into an amine. The reaction may proceed through the intermediate formation of ethylenimine, yielding an aminoethyl derivative.

As seen in Tables II-IV, dialkylamines react with the substituted terminal acetylenes to give only trans-aminovinyl products. Primary aliphatic amines react with both ethyl propiolate and 1-ethylsulfonyl-l-propyne to give mixtures of cis and trans products and with p-tolylsulfonylacetylene to give only trans products. Ethylenimine reacts with ethyl propiolate and 1-ethylsulfonyl-l-propyne to give mixtures of cis and trans products. Aniline reacts with p-tolylsulfonylacetylene to give a mixture of cis and trans products. The solvent has a great effect on the cis- and trans ratio when ethylenimine is used. 

Ethylenimines may also be prepared by the reaction of 1,2-dihaloalkanes with amines or ammonia. For example, ethylenimine may be prepared in the laboratory or on an industrial scale by the reaction of ethylene dichloride with ammonia [42]. The reaction of amines with a,/3-dibromo ketones yields imines as described in Eq. (18) [43]. 

An interesting polymer constrained to a relatively compact conformation is polyethylenimine (PEI), which can be prepared by suitable polymerization of ethylenimine (Fig. 2) to give a highly branched rather than a linear macromolecule.19 The structure of a segment of this polymer is shown in Fig. 2. Approximately 25% of its nitrogens are primary amines, 50% secondary, and 25% tertiary.19 The branching of the polymer may be represented schematically as shown in Fig. 3. 

Deacylation rates of acetylsalicylate by isopropylated polymer at pH 7.3 were markedly slower than with unmodified polymer (Table III). With 2.4xlO-2 total residue molar concentration of isopropylated and unmodified poly(ethylenimine), respectively, k2, the pseudo-first-order rate for the former was 1.45 x 10-3 min-1, for the latter 1.2 x 10-1 min-1. Clearly, primary amines are the major sites for aminolysis of aspirin. 

As Fig. 15b illustrates, the graphical relation appears to be linear for an interaction number of 3 to 4, if A 1. Alternatively, for A = 1, linearity is evident (Fig. 15c) when the interaction number is 5 to 6. Thus a large value of A is compatible with the smallest interaction number. Excimer formation occurs within the fluorescence lifetime, about 8 nsec. Within that time the pyrene-labeled amine side chains must approach within about 4 A of each other. For the 5.3% pyrenylpolyethylenimine derivative in ethanol, where no ground-state association occurs, the effective local concentration of pyrene on the polymer matrix is about 10-2 M, as calculated from excimer fluorescence. In aqueous solution, where clusters form within the polymer matrix, the effective local concentration of pyrene adduct must be even greater. The quantitative assessment of fluorescence intensities (Fig. 15) points to a minimum interaction number of 3 to 4 pyrenyl-labeled amine side chains, within the 8 nsec lifetime. Since A 1, it appears from (12) that kDM(A) kMD + kD. Thus excimer formation must be very rapid in the polymer environment. We can conclude, therefore, that the primary-amine side chains of poly-ethylenimine are very flexible and mobile. 

It became of interest to see if we could obtain any indication of Schiff base formation with the polymer. Since spectroscopic probes would be obscured with the actual substrate, oxalacetate, because of the progress of the decarboxylation reaction (32), we have examined instead the spectra of oxalacetate-4-ethyl ester in solutions of the same modified poly-(ethylenimine) PEIQ—NH2. Such solutions develop a new absorption band at 290 nm. Furthermore, this band is essentially abolished if NaBH4 is added to the solution (Fig. 21). As is well known, NaBH4 reduces Schiff base linkages to amine groups.43-44... 

It has also been possible to confirm the presence of the reduction product of a Schiff base on the polymer by proton magnetic resonance. For this purpose we have used unmodified poly(ethylenimine), since it too catalyzes the decarboxylation of oxalacetate to its product, pyruvate. Unmodified polyethylenimine was mixed with oxalacetate-4-ethyl ester. One-half of this solution was treated with NaBH4 the second half was exposed to a similar environment but no NaBH4 was added. The borohydride-treated polymer exhibited a strong triplet in the nmr spectrum centered at 3.4 ppm upfield from the HOD resonance. This new feature would be expected from the terminal methyl protons of the oxalacetate ester attached to the polymer. Only a very weak triplet was found in the control sample not treated with borohydride. These observations are strong evidence for the formation of Schiff bases with the polymer primary amine groups. Evidently the mechanistic pathway for decarboxylation by the polymer catalyst is similar to that used enzymatically. 

A variety of mono-, di-, tetra-, and polydendron PAMAMs have been synthesized from simple amines as well as linear polyamine cores [2, 83, 124]. Linear poly(ethylenimines) with core multiplicities (Nc of ca. 300-400) have been shown to produce high-aspect ratio, rod-like dendrimers at generation 3 or 4 [2]. Their length is determined by the degree of polymerization (n) of the initiator core and their diameter is derived from the number of generations (see Scheme 3). 

Poly(ethylenimine) (PEI) has been examined extensively both in its classical, random branched topology [125] and in its linear form [126]. The various architectural and topological forms of PEI have been reviewed recently [127], Here we describe the first example of this polymer system as an ideal, hyper-branched molecular assembly. Synthesis of a tri-dendron poly(ethyleneimine) dendrimer derived from an ammonia core involved, first the selective alkylation of diethylenetriamine (DETA) with aziridine to produce a symmetrical core cell, namely tris-(-2-aminoethyl)amine. Subsequent exhaustive alkylations of the terminal amino moieties with activated aziridines [2, 127, 128], such as IV-tosyl- or N-mesylaziridine gave very good conversions to the first-generation protected... 

Reaction of various primary amine-terminated dendrimers with either inorganic or organic acids allows the preparation of a wide variety of crystalline derivatives. One such intermediate was implicated in the development of lyotropic phases [156] when octanoic acid was combined with Starburst poly(ethylenimine) (generation-3). 

Anion-exchange resins have also been prepared through the nitration of SDVB copolymers with sulfuric acid-nitric acid mixture followed by the reduction of nitro groups with sodium sulfide . Such resins containing —NHj groups have been further modified with ethylenimine or hydroxylamine Aminated polystyrene can be crosslinked with dichloroethane to give an anion-exchange resin... 

N-Alkyl- and N,N-dialkyl-ethylenediamines are prepared in a single step (cf. methods 427, 435, and 452) by the addition of gaseous ethylenimine to primary or secondary amines in the presence of anhydrous aluminum chloride (77-89%). Primary amines react at about 90° with benzene as solvent, whereas secondary amines react at 180° with tetralin or biphenyl as solvent. In a similar manner, homologs of ethylenimine and ammonia (or amines) react in high-pressure equipment at 100° in the presence of ammonium chloride. "... 

Lewis base adducts of U(OCFl2CH3)5 have been prepared with acetonitrile, THF, pyridine, and SO2, " and adducts of U(OCFl2CF3)5 were prepared with a number of aliphatic amines (NMes, NPrFl2, NPr Fl2, NPr2Fl, NMc2H, ethylenimine). Later reports of the synthesis of poly-fluoroalkoxides ethanol adducts U[OC(CF3)3]4(OCF[2CF[3)(F[OCF[2CF[3), and U[OCH-(CF3)2]4(OCF[2CF[3XEIOCF[2CF[3) from the reaction between the respective fluorinated alcohol with U(0CF[2CF[3) " determined these complexes to be monomeric. 

Gabriel ethylenimine method. Formation of ethylenimines (aziridines) by elimination of hydrogen halides from aliphatic vicinal haloamines with alkali. The method can be extended to the preparation of five- and six-membered ring amines. 

Many complexing polymers have been shown to be very promising for commercial metal enrichment and separation. Among those, amine polymers such as poly(allylamine) (PAL) and poly(ethylenimine) (PEI) have been found suitable for metal extraction. The main types of the different interaction products of metal ions with functional polymers are shown in Figure 9. 

Polyethylenimine is a product of the self-condensation of the strained-ring compound ethylenimine (aziridine, azacyclopropane). It is a globular molecule having a not quite statistical distribution of amine groups (30% primary, 40% secondary and 30% tertiary amine). The most effective molecular weight range for this water-soluble polymer in composite membrane fabrication has been 10,000 to 60,000. 

The ethylenimine (aziridine) ring is much harder than the oxirane ring to open by ammonia or amines catalysts such as ammonium chloride1142 and aluminum chloride1143 have been added. 

Ethylenimine is used in the manufacture of triethylenemelamine and other amines. 

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