AMMONIUM PYRROLIDONE

In a further approach, protective agents may be added to prevent the interfering substance from reacting with the analyte. Stable, but volatile complexes or compounds are formed between the analyte and the protective agent. These protective agents are very often complexing agents, such as ethylenediamine tetraacetate (EDTA), ammonium pyrrolidone-dithiocarbamate (APDC), or 8-hydroxychinoline. 

The comparative experiments of Table I show that both py-K/C02 and TMAC are essential for the formation of ultrahigh molecular weight polymers. This observation is consistent with the results of earlier investigators who obtained relatively low molecular weight ([n] = 1.6 dl/g, Mw = 48,000) nylon 4 with pure or in-situ generated quaternary ammonium pyrrolidonate catalysts. 

An efficient sample pretreatment/introduction technique for the inductively coupled plasma atomic emission spectrometry (ICP-AES) using ion exchange for analyte preconcentration and matrix separation and laser ablation sampling for sample introduction was developed. Ammonium pyrrolidone dithiocarbamate-PS films were coated on glass plates for analyte preconcentration. 32 refs. HONG KONG Accession no. 662915... 

Photolysis or thermolysis of heteroatom-substituted chromium carbene complexes can lead to the formation of ketene-like intermediates (cf. Sections 2.2.3 and 2.2.5). The reaction of these intermediates with tertiary amines can yield ammonium ylides, which can undergo Stevens rearrangement [294,365,366] (see also Entry 6, Table 2.14 and Experimental Procedure 2.2.1). This reaction sequence has been used to prepare pyrrolidones and other nitrogen-containing heterocycles. Examples of such reactions are given in Figure 2.31 and Table 2.21. 

As a t rpical example. Scheme 3 shows the possible formation of five-membered ring systems with two heteroatoms in the aceto-in-ammonium sulfide model system (Barone, R., Universite d Aix-Marseille III, unpublished results, 1986). Similar predictions can be made for the formation of substituted pyrrolidones and for additional five- and six-membered rings. 

Ammonium quaternary salt containing a double bond such as [2-hydroxy-3-(methacryloyloxy)propyl]trimethylammonium chloride can be used as a grafting reagent to improve the hydrophylic properties of polyamides (63). Still other compounds as vinyl pyrrolidone (23) and methacryloxy stannane (64), seem to be useful for Nylon grafting under cobalt-60 irradiation. 

A recent report describes the presence of pyrrolidone carboxylyl peptidase in rat liver (46). A partial purification of the enzyme has been obtained by ammonium sulfate fractionation and gel filtration on Sepha-dex G-200. The rat liver enzyme is similar to that obtained from Pseudomonas thus, it is protected against inactivation by 2-pyrrolidone and exhibits similar substrate specificity. 

It has been demonstrated that the oxygen anion of initially formed product (36) effectively catalysed the [2,3]-Wittig rearrangement as a Lewis base. Other Lewis-base catalysts such as lithio or sodio 2-pyrrolidone promote the same [2,3]-Wittig rearrangement of silyl enolates generated from a-allyloxy ketones, whereas rearrangements of enolates from a-allyloxy esters were efficiently catalysed by ammonium 4-methoxybenzoate.24... 

The above mentioned hydroxy and epoxy functional silanes represent reactive intermediates which can be transformed into ionic trimethyl silane derivatives. To give an example, hydroxyhexyltrimethylsilane can be reacted with sulfamic acid in the presence of a polar aprotic solvent such as f -methyl pyrrolidone or dimethyl formamide. The transformation of the ammonium salt into the appropriate alkyl ammonium derivative is readily achieved by addition of amine under generation of ammonia gas. 

Regarding the initiation process of polymerization, it can be started by y-radiation. It is a method that has been used for the synthesis of hydrogels of PEO as well as hydrogels based on vinyl monomers " in this latter case, azo-compounds such as 2,2-azo-isobutyroni-trile (AIBN)f or 2,2 -azobis (2-amidine-propane) dihydrochloride or V-SO, and aqueous salt solutions such as aqueous ammonium peroxodisulfate are also used. Among the monomers most used in the preparation of hydrogels through free-radical polymerization are 2-hydroxyethyl methacrylate (HEMA) and A-vinyl-2-pyrrolidone (VP). ... 

Our bi- and tri-metallic species are derived from precursor molecules that can be denuded (chemically) to expose only the mixed-metal constituent atoms. The nanoalloys that almost all others prepare are generally formed by methods that rely on sequential addition of separate solutions such as HAuCl and PdCl [35] to form Au-Pd nanoalloys. Moreover, such nanoalloys (like the metallic nanoparticles now in extensive use [45]) are utilized in their passivated form, which means that they have surfactant species such as poly(vinyl pyrrolidone), PVP, or poly-diaUyl dimethyl ammonium chloride (PDDA) covering their surfaces (The molecular weight of which may be as large as 450 kDa). Our nanoparticles are free from such surfactants or any other stabilizing molecular entity. 

The synthesis of (+)-cucurbitin (26) may be achieved starting from 1-carbe-thoxy-3-pyrrolidone (180). Reaction of 180 with KCN and ammonium chloride in aqueous methanol gives an adduct which is refluxed with 48% HBr to afford cucur-bitin hydrobromide. Resolution of (+)-cucurbitin with (+)-camphoric acid yields (-) 26-(+)-camphorate (m.p. 195-96°C) from which free base is liberated to give (-)-cu-curbitin (26) [126b]. 

Earlier, the reduction of y-nitro esters with zinc and ammonium chloride had been shown49 to provide a suitable route to iV-hydroxy 2-pyrrolidones, e.g., 42. Various catalytic hydrogenation procedures can also effect the same reductive cyclization.49,80... 

Fuchigami and coworkers have formed emlates with electrogenerated bases (equations 10 and 11). - The basic anions of 2,6-di-r-butyl-p-cresol and a-pyrrolidone were obtained by cathodic reduction. Countercations with a weak affinity for the fluorine atom e.g. quaternary ammonium, phosphonium or tertiary sulfonium cations) had to be used in the example shown in equation (11) in order to impede defluorination. 

Melamine is soluble only in water and has low solubility in dimethylsulfoxide (DMSO) and in other aprotic dipolar solvents (9% at 120 °C), in glycerol or ethylene glycol (10% at 140 °C). In the majority of other usual solvents it is insoluble. Kucharski and Lubczak discovered a new class of reactive solvents for melamine [36] poly (hydroxymethyl) derivatives of cyclohexanone, acetone, nitromethane which are able to dissolve 50-60% melamine. Melamine can be totally propoxylated or ethoxylated at lower temperatures (70-90 °C), in aprotic dipolar solvents (for example DMSO, dimethylformamide, N-methyl pyrrolidone and so on), in the presence of quaternary ammonium hydroxides as catalysts [for example tetrabutyl ammonium hydroxide (TBAH)], at a low reaction rate (reaction 15.35), for a very long reaction time (40-50 hours) [31, 37]. The resulting hexafunctional polyols give very thermostable rigid PU (up 200 °C). 

Cationic polymers such as polymer JR (polyquaternium-10), a quater-nized cellulosic ingredient [6] cationic guar, a quaternized polymer of galactose Merquat polymers (polyquaternium-6 and -7) copolymers of dimethyl diallyl ammonium chloride and acrylamide [7] and Gafquat polymers (polyquaternium-11) (copolymer of polyvinyl pyrrolidone and dimethy-laminoethyl methacrylate) [8] have all been used and are currently used in conditioning shampoos, setting lotions, or mousses. 

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