Study of reaction between N,N,N′,N′,N′-pentakis (hydroxymethyl) melamine and ethylene or propylene oxide

The effects of the kind and amount of oxirane (propylene or ethylene oxide), the amount of triethylamine catalyst, and the temperature on the reaction with N,N,N′,N′,N′-pentakis (hydroxymethyl) melamine (PHMM) in DMSO solution were studied. The changes in the content of reactive groups in the reaction mixture and in the final product were analyzed. The oxirane addition was shown to be accompanied by the condensation of hydroxymethyl groups in the PHMM. Optimal conditions for the synthesis and the structural formula of the s-triazine ring containing polyetherols were established. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2589–2602, 1997     

Reactions taking place in the system N,N,N′,N′,N″‐ pentakis(hydroxymethyl)melamine–oxirane in aqueous media

The results of studies on effects of the amount and type of oxirane, amount of catalyst and water, and temperature on the course of reactions taking place in the system N,N,N′,N′,N″‐pentakis(hydroxymethyl)melamine (PHMM)–oxirane carried out in aqueous media are reported. Quantitative determination of the content of functional groups present in the system and of side products formed in reactions of oxirane with water, made it possible to analyze in detail the processes taking place in the system. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 824–836, 2000     

α-Substituierte Phosphonate. XXXI. Zur Reaktion von N,N,N′,N′-Tetramethylchlorformamidiniumchlorid mit P-III-Verbindungen

α-Substituted Phosphonates. XXXI. The Reaction of N,N,N′,N′-Tetramethyl Chloroformamidinium Chloride with P(III) Compounds N,N,N′,N′-Tetramethyl chloroformamidiniumchloride ( 4 ) does not react with triethyl phosphite (TEP) or isopropyl diphenylphosphinate to give the expected bisphosphoryl derivatives 7 and 11 , respectively, but primarily the monophosphorylated amidinium salts 6 and 10 respectively. The phosphine oxide 10 is stable, while 6 undergoes an elimination of ethyl chloride to the betain 8 . Even under more drastic conditions the reaction of 4 or 8 with TEP does not lead to the expected bis(dimethylamino)bisphosphonate 7 , but to the monoaminated bisphosphonate 1 , involving a reduction step. Similar reduction has been observed under mild conditions in Michaelis-Arbusov reaction of dichloromethylenimonium chloride, yielding the expected trisphosphonate 2 and the bisphosphonate 1 as a by-product.     

Epoxy resins based on aromatic glycidylamines. VI. Toughening of N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane by reactive additives

Mechanical properties of N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane and its mixtures with liquid bisphenol A-type epoxy resins, bisphenol A and ε-caprolactone have been studied. 4,4′-Diaminodiphenylsulfone was used as hardener. Materials with improved fracture toughness and good mechanical strength in the temperature range 20–200°C have been formulated.     

Transport of lanthanides and fission products through supported liquid membranes containing N,N,N′,N′-tetraoctyl diglycolamide (TODGA) as the carrier

Facilitated transport of trivalent lanthanides, viz. La(III), Eu(III), Lu(III) and several fission product elements such as Tc, Mo, Zr, Pd, I, Cs and Ru across a flat sheet supported liquid membrane made of PTFE impregnated with N,N,N′,N′-tetraoctyl diglycolamide (TODGA) in n-dodecane was investigated from dilute nitric acid solutions. The transport rates of lanthanides increased with nitric acid concentration in a manner similar to their distribution ratios. The trend in metal ion transport after 75 min followed the order: La > Eu > Lu > Zr > Sr > I > Pd ~ Tc > Ru > Mo ~ Cs, which was consistent even after 5 h of operation. However, the transport of I reached the maximum value of ~26% in 100 min and remained constant thereafter. In the case of Am(III) transport studies, excellent decontamination from Zr was achieved when 0.4 M oxalic acid was added to the feed solution.     

Atom‐transfer radical polymerization of methyl methacrylate with α,α′‐dichloroxylene/CuCl/N,N,N′,N″,N″‐pentamethyldiethylenetriamine initiation system under microwave irradiation

The atom‐transfer radical polymerization (ATRP) of methyl methacrylate (MMA), using α,α′‐dichloroxylene as initiator and CuCl/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as catalyst was successfully carried out under microwave irradiation (MI). The polymerization of MMA under MI showed linear first‐order rate plots, a linear increase of the number‐average molecular weight with conversion, and low polydispersities, which indicated that the ATRP of MMA was controlled. Using the same experimental conditions, the apparent rate constant (k) under MI (k = 7.6 × 10^?4 s^?1) was higher than that under conventional heating (k = 5.3 × 10^?5 s^?1). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2189–2195, 2004     

Substituierte N,N′-Bis(thiazol-2-yl)-diaminoalkane aus α-Thiocyanato-acetophenonen und N,N′-Dialkyl-diamino-alkanen

Substituted N,N′-Bis(thiazol-2-yl)-diaminoalkanes from α-Thiocyanato-acetophenones and N,N′-Dialkyl-diaminoalkanes α-Thiocyanato-acetophenones 1 react with N,N′-dialkyl-diaminoalkanes 2 in the presence of an appropriate weak acid (acetic acid, propionic acid, benzoic acid) to give the hitherto unknown N,N′-dialkyl-N,N′-bis(4-aryl-thiazol-2-yl)-diaminoalkanes 3 . As reaction medium aliphatic alcohols (ethanol, methanol), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) or dipolar-aprotic solvents (acetonitrile, dimethylformamide) can be used. - I.r., u.v., n.m.r. and mass spectroscopic data of the novel bisthiazoles 3 are reported.     

Polymerization of styrene using N-(p-tolyl)-N′,N′-diethyldithiocarbamoylacetamide as photoiniferter

N-(p-Tolyl)-N′,N′-diethyldithiocarbamoylacetamide was prepared and used as a new photoiniferter for polymerization of styrene in bulk under UV light. This photopolymerization showed some specific character, i.e., molecular weights of resulting polymers increase with reaction time and monomer conversion, respectively. The reversible reaction between growing radical and dormant species was confirmed by electron spin resonance using 2-methyl-2-nitrosopropane as a spin trapping agent. Thus, the end functionalized polymer, N,N-diethyldithiocarbamoyl-terminated polystyrene, reinitiated photopolymerization of methyl methacrylate and vinyl acetate to form block copolymers. The molecular weight distribution about 2.7 indicated that the polymerization is not a strictly living radical polymerization. © 1996 John Wiley & Sons, Inc.     

Polycarbonate/(N,N′-dialicylidene ethylene diamine) cobalt(II) complex membrane for gas separation

A polycarbonate/(N,N′-dialicylidene ethylene diamine) cobalt(II) (cosalen) complexed membrane was prepared by introducing oxygen carrier (cosalen) into polycarbonate for gas separation. With increasing amount of oxygen carrier in the membranes, the selectivity of O₂/N₂ increased and the permeabilities of both O₂ and N₂ decreased. The selectivity of O₂/N₂ decreased with increasing operating temperature. The pure gases sorption measurements indicated that the affinity between oxygen and the membranes was appreciable higher than that of nitrogen. According to the X-ray analysis of the complexed membranes, the decreased gas diffusivities were caused by the increase of the packing density. The selectivity of O₂/N₂ was 15 and oxygen permeability for the cobalt complexed membrane with 3 wt % oxygen carrier was 0.33 barrers at 5°C. Furthermore, a dual mode sorption mechanism was utilized to describe the behavior of gas sorption and permeation through the cobalt complexed membrane. © 1996 John Wiley & Sons, Inc.     

Water Solvent Method for Esterification and Amide Formation between Acid Chlorides and Alcohols Promoted by Combined Catalytic Amines: Synergy between N‐Methylimidazole and N,N,N′,N′‐Tetramethylethylenediamine (TMEDA)

An efficient method for esterification between acid chlorides and alcohols in water as solvent has been developed by combining the catalytic amines, N‐methylimidazole and N,N,N′,N′‐tetramethylethylenediamine (TMEDA). The present Schotten–Baumann‐type reaction was performed by maintaining the pH at around 11.5 using a pH controller to prevent the decomposition of acid chlorides and/or esters and to facilitate the condensation. The choice of catalysts (0.1 equiv.) was crucial: the combined use of N‐methylimidazole and TMEDA exhibited a dramatic synergistic effect. The catalytic amines have two different roles: (i) N‐methylimidazole forms highly reactive ammonium intermediates with acid chlorides and (ii) TMEDA acts as an effective HCl binder. The production of these intermediates was rationally supported by a careful ¹H NMR monitoring study. Related amide formation was also achieved between acid chlorides and primary or secondary amines, including less nucleophilic or water‐soluble amines such as 2‐(or 4‐)chloroaniline, the Weinreb N‐methoxyamine, and 2,2‐dimethoxyethanamine.     

Studies on the curing kinetics and thermal stability of the novel tetrafunctional epoxy resin N,N,N′N′-tetrakis(2,3-epoxypropyl)-4,4′-(1,4-phenylenedioxy)dianiline

A novel tetrafunctional epoxy resin, namely N,N,N′N′-tetrakis(2,3-epoxypropyl)-4,4′-(1,4-phenylenedioxy)dianiline, has been synthesized. The curing kinetics has been studied by differential scanning calorimetry (DSC) using various amine curing agents. Thermal stabilities of the cured products have been investigated by thermogravimetric (TG) analyses. The overall activation energies for the curing reactions are observed to be in the range 63.6–196.7 kJ·mol^–1. The cured products have good thermal stability.     

Synthesis,characterization, and properties of low viscosity tetra‐functional epoxy resin N,N,N′,N′‐ tetraglycidyl‐3,3′‐diethyl‐4,4′‐diaminodiphenylmethane

Tetra‐functional epoxy resin N,N,N′,N′‐tetraglycidyl‐3,3′‐diethyl‐4,4′‐diaminodiphenylmethane (TGDEDDM) was synthesized and characterized. The viscosity of TGDEDDM at 25°C was 7.2 Pa·s, much lower than that of N,N,N′,N′‐tetraglycidyl‐4,4′‐diaminodiphenylmethane (TGDDM). DSC analysis revealed that the reactivity of TGDEDDM with curing agent 4,4′‐diamino diphenylsulfone (DDS) was significantly lower than that of TGDDM. Owing to its lower viscosity and reactivity, TGDEDDM/DDS exhibited a much wider processing temperature window compared to TGDDM/DDS. Trifluoroborane ethylamine complex (BF₃‐MEA) was used to promote the curing of TGDEDDM/DDS to achieve a full cure, and the thermal and mechanical properties of the cured TGDEDDM were investigated and compared with those of the cured TGDDM. It transpired that, due to the introduction of ethyl groups, the heat resistance and flexural strength were reduced, while the modulus was enhanced. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40009.     

Epoxy resins based on aromatic glycidylamines. IV. Preparation of N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane from aniline and analysis of the product by GPC and HPLC

Epoxy resins containing N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) were prepared from aniline and epichlorohydrin and analyzed by GPC and HPLC. The product composition was compared with that of resins prepared from 4,4′-diaminodiphenylmethane (DDM) and epichlorohydrin, which had been analyzed in our previous work. A new byproduct designated Y4 was isolated by semipreparative HPLC and identified by NMR and mass spectroscopy. The course of formaldehyde condensation with N,N-dichlorohydrin of aniline (DCHA) was followed by GPC and HPLC and the mechanism of formation of Y4 was proposed on the basis of obtained results. Attention was also paid to the differences in reactivity of DCHA diastereoisomers.     

Polarographic studies of lead(II) complexes with triethylenetetramine-N,N, N,′ N,″ N″', N″'-hexaacetic acid

Three different polarographic waves of lead(II)-TTHA system explored from limiting currents, half-wave potentials and reciprocal slopes of the log-plots and analysed to determine the kinetic parameters. The reduction for the first wave (A) was reversible or irreversible involving partially kinetic-controlled reaction with the change of pH and molar ratio of lead(II): TTHA. The second wave (B) is proposed to occur as the results of the adsorption of dissociated ligand anion on the dme. The third wave (C) at more negative potential ( -0.831 V vs sce, pH = 4.32) was assigned to an irreversible reduction of the complex PbH₂L (pH ? 5.27) or PbHL(pH > 5.27). The mechanisms of the electrode reaction of wave (C) are expressed as follows.

where k_j denotes the rate constant of electrodics.For the mechanisms (I) and (II) the values of k_j were determined from the dependence of the half-wave potential on the hydrogen ion concentration. They were 2.98 X 10^t-3 and 1.45 X 19^t-9 cm/s, respectively.     

Solution NMR study of the post-polymerization crosslinking agent N,N′-(2-propyloximino)-4,4′-methylenebis(phenylcarbamate). I

Because of its possible use as a blocked “post-polymerization crosslinking agent” for polymers containing labile hydrogen, the structure of the acetone oxime adduct of 4,4′-methylenebis-(phenylisocyanate) has been determined. ¹³C and ¹H nuclear magnetic resonance (NMR) spectroscopy has identified this product to be N,N′-(2-propyloximino)-4,4′-methylenebis(phenylcarbamate). Chemical shift assignments were based on information obtained by proton decoupled, off-resonance decoupled, and gated decoupled ¹³C-NMR, proton-NMR, and semiemperical substituent chemical shift (SCS) parameters.     

Properties of poly[N,N′-(4,4′-diphenyl ether) 4-amidophthalimide] film

A high molecular weight polyamide–imide polymer derived from the reaction of TMAC–DAPE has been prepared and its film properties have been evaluated. Poly-[N,N′-(4,4′-diphenyl ether) 4-amidophthalimide] film has an excellent combination of mechanical, electrical, and chemical properties at room temperature and at 200°C. A comparison of the film properties of this material with those of a commercial polyimide film, Teflon, FEP, Nomex paper, and Mylar films is also presented.     

Synthesis of N,N′-Bis(2-Nitro-Benzodifuroxanyl)-1,3,5-Trinitro-2,6-Diaminobenzene

N,N′-Bis(2-nitro-benzodifuroxanyl)-1,3,5-trinitro-2,6-diaminobenzene has been synthesized from 1,3-diaminobenzene and trinitrotrichlorobenzene. The molecular structure of this compound has been determined by elemental analysis, IR, ¹HNMR, and MS spectroscopies.     

Synthesis of N,N′-bis(2,4-dinitrobenzofuroxan)-1,3,5-trinitro-2,6-diaminobenzene

N,N′-bis(2,4-dinitrobenzofuroxan)-1,3,5-trinitro-2,6-diaminobenzene (V) has been synthesized from 1,3-diaminobenzene and trinitrodichlorobenzene. The molecular structure of this compound has been determined by elemental analysis, IR, ¹H-NMR, and MS spectroscopies.     

Grafting of N,N′-methylenebisacrylamide onto silk fibers using the vanadylacetylacetonate complex in aqueous medium

The grafting of N,N′-methylenebisacrylamide (N,N′-MBA) onto mulberry silk fibers is reported using vanadylacetylacetonate (VO(acac)₂) complex under inert atmosphere at 50°C. The effect of various variables like, concentration of N,N′-MBA and VO(acac)_2, acidity of the medium and the surfactants on the percentage grafting have been investigated. The higher rate of radical formation has been explained due to the coordination of π-electrons of the N,N′-MBA with the metal chelate which has assisted in the cleavage of M? O bond to generate radical easily. A plausible mechanism for graft copolymerization involving cyclization of N,N′-MBA prior to the grafting has been proposed.