Synthesis, characterization and curing studies of thermosetting epoxy resin with amines

A new hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) is prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with Epichlorohydrin by using benzyltrimethylammonium chloride as a catalyst. The resulting compound possesses both the oxirane ring and maleimide group. The curing reaction of these maleimidophenyl glycidylether epoxy compound (N-MPGE) with amines as curing agents such as ethylendiamine (EDA), diethylentriamine (DETA) and triethylenetetramine (TETA), aminoethylpiperazine (AEP) and isophoronediamine, IPDA), are studied. Incorporation of maleimide groups in the epichlorohydrin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples exhibited good thermal stability, excellent chemical (acid/alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity net work of the cured systems

Preparation and reactivity studies of maleimidophenyl glycidylether with amines

The hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) was prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with epichlorohydrin by using benzyltrimethylammonium chloride as a catalyst. The resulting compound possessed both the oxirane ring and maleimide group. The curing reaction of N-MPGE with amines as curing agents such as tetraethylenepentamine (TEPA), bishexamethylenetriamine (BHMT), 2-methyl pentamethylenediamine (2-MPMDA) and 2,2,4-trimethy diamines (2,2,4-TMDA) was studied. The cured samples exhibited good thermal stability and excellent chemical (acid/alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity network of the cured systems. © 2011 Chemical Society of Ethiopia

Ru(III)​-​catalyzed oxidation of some amines by chloramine-​T in hydrochloric acid medium: Mechanistic aspects and kinetic modeling

A review. The kinetics of oxidn. of five amines viz., ethylenediamine (EDA)​, diethylenetriamine (DETA)​, triethylenetetramine (TETA)​, aminoethylpiperazine (AEP) and isophoronediamine (IPDA) by sodium N-​chloro-​p-​toluenesulfonamide or chloramine-​T (CAT) in the presence of HCl and Ru(III) chloride was studied at 303 K. The five reactions followed identical kinetics and the exptl. rate law is rate = k[CAT]​0[amine]​x0[H+]​y[Ru(III)​]​z, where x, y and z are fractions. A variation of the ionic strength or dielec. const. of the medium and the addn. of halide ions and p-​toluenesulfonamide had no significant effect on the rate of the reaction. The solvent isotope effect has been studied in D2O medium. The activation parameters have been evaluated from the Arrhenius plots. Under comparable exptl. conditions, the rate of oxidn. of amines increases in the order: AEP > TETA > DETA > EDA > IPDA. An isokinetic relationship is obsd. with β = 377 K, indicating enthalpy as a controlling factor. Oxidn. products were identified. CH3C6H4SO2+NH2Cl of the oxidant has been postulated as the reactive oxidizing species. Further, the kinetics of Ru(III)​-​catalyzed oxidn. of these amines have been compared with unanalyzed reactions (in the absence of Ru(III) catalyst) and found that the catalyzed reactions are 2-​3-​fold faster. The catalytic const. (KC) was also calcd. for each amine at different temps. from the plots of log KC against 1​/T, values of activation parameters with respect to the catalyst have been evaluated. The obsd. results have also been explained by a plausible mechanism and the related rate law has been deduced

Preparation and reactions of chromium(III) alkoxides

Reactions of CrCl3.3THF with LiOR (R = Me, Et, Bu) in 1:3 molar ratio in ROH yield insol. Cr(OR)​3. The corresponding reactions with R = Me2CH and Me3C yield hydrolyzed products only; these compds. were prepd. by alternative routes. All the alkoxides were characterized by physicochem. methods. Attempts were made to study their alcoholysis reaction

Synthesis of co(II), Ni(II) and Cu(II) complexes from schiff base ligand and reactivity studies with thermosetting epoxy resin

A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II), Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-(Z)-2-piperazin-1-yl- ethylimino-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen

Synthesis, characterization, antibacterial, antifungal and anthelmintic activities of a new 5-​nitroisatin Schiff base and its metal complexes

The copper (II)​, cobalt (II)​, nickel (II) and zinc (II) complexes of 5 - nitroisatin Schiff base (L) (L = Schiff base derived from 5-​nitroisatin and 2-​methyl-​4-​nitroaniline) were synthesized and characterized. The authenticity of the ligand and its metal complexes has been established by micro anal., IR, NMR, LC​/MS, UV-​VIS and elec. conductance measurements. The ligand acts as a bidentate agent in which the carbonyl oxygen and the azomethine nitrogen of 5-​nitroisatin are involved in co-​ordination. Square planar geometry was proposed for the Cu (II) and Ni (II) complexes and tetrahedral geometry was proposed for the Co (II) and Zn (II) complexes. The ligand and its metal complexes have been screened for antibacterial activity against Staphylococcus aureus, Escherichia coli, etc. and for antifungal activity against Aspergillus niger, Aspergillus flavous, etc. The Schiff base and its complexes were also screened for anthelmintic activity on earthworms. Both samples displayed significant activitie

Preparation and curing studies of maleimide bisphenol-A based epoxy resins

Maleimide modified epoxy compounds were prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with diglycidylether of bisphenol-A. Triphenylphosphine was used as catalyst and methylethylketone as solvent. The resulting compound possessed both the oxirane ring and maleimide group. The curing reaction of the maleimide epoxy compound with amine curing agents such as 1-(2-aminoethyl) piperazine (AEP) and 5-amino-1,3,3-trimethylcyclohexane methylamine isophorone diamine, IPDA) were studied. Incorporation of maleimide groups in the epoxy resin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples were found to have good thermal stability, chemical resistance (acid/alkali/solvent) and water absorption resistance

Copper complex of isatin Schiff base encapsulated in zeolite as active heterogeneous catalyst: an efficient protocol for the acetylation reaction

Copper (II) complex of 3-phenylimino-1,3-dihydro-indol-2-one encapsulated in the super cages of zeolite-Y has been synthesized by flexible ligand method and characterized by various physicochemical measurements. The catalytic activity of cationic exchanged zeolite, copper complex of ligand and complex encapsulated inside the zeolite was investigated for the decomposition of H2O2 and for the acetylation of p-cresol. All catalysts show good to excellent yield. The results showed that conversion of p-cresol varies in the order homogeneous complex \NaY-Zeolite\Cu-Y-Zeolite\heterogeneous comple

Synthesis, Characterization and Biological Activities of a New 5-Chloroisatin Schiff Base and its Metal Complexes

Copper(II), cobalt(II), nickel(II) and zinc(II) complexes of 5-chloroisatin Schiff base (L) (L= Schiff base derived from 5-chloroisatin and 2-methyl-4- nitro aniline) were synthesized and characterized. The authenticity of the ligand and its metal complexes had been established by micro analysis, IR, NMR, LC/MS, UV-Vis and electrical conductance measurements. The ligand acts as a bidentate in which the carbonyl oxygen and the azomethine nitrogen of 5-chloroisatin are involved in co-ordination. Square planar geometry was proposed for Cu(II) and Ni(II) complexes and tetrahedral geometry was proposed for Co(II) and Zn(II) complexes. The ligand and its metal complexes have been screened for their antibacterial activity against bacterias viz. Staphylococcus aureus and Escherichia coli etc. and antifungal activity against fungi Aspergillus niger and Aspergillus flavous etc. The activities of both the samples have shown significant and noticeable changes on complexations

Zeolite-​encapsulated 2-​(o-​aminophenyl)​benzimidazole complexes: synthesis, characterization and catalytic activity

Cobalt(II)​, copper(II) and zinc(II) complexes of 2-​(o-​aminophenyl)​benzimidazole (AmPhBzlH) encapsulated in the super cages of zeolite-​Y and ZSM-​5 were synthesized and characterized by spectroscopic studies (IR, UV​/visible, EPR)​, elemental analyses, thermal studies and x-​ray diffraction patterns. The catalytic activity of encapsulated complexes was studied for the hydroxylation of phenol using 30​% H2O2 as an oxidant. Under optimized reaction conditions, the hydroxylation of phenol yielded catechol and hydroquinone as the major products. All catalysts show good selectivity for diphenol products. A max. conversion of phenol was obtained with [Cu(AmPhBzlH)​]​-​Y as the catalyst. Conversion of phenol varies in the order [Cu(AmPhBzlH)​]​-​Y > [Cu(AmPhBzlH)​]​-​ZSM-​5 > [Zn(AmPhBzlH)​]​-​Y > [Co(AmPhBzlH)​]​-​Y > [Zn(AmPhBzlH)​]​-​ZSM-​5 > [Co(AmPhBzlH)​]​-​ZSM-​5 after 6 h of reaction time. Test for the recyclability of the reaction was also carried out and the results indicate their recyclability