Search results
1 – 10 of 14R.D. Kulkarni, M.E. Chaudhari and S. Mishra
The purpose of this paper is to provide a critical and in‐depth review of the present status and recent developments in synthetic methodologies, reaction engineering, process…
Abstract
Purpose
The purpose of this paper is to provide a critical and in‐depth review of the present status and recent developments in synthetic methodologies, reaction engineering, process design and quality control aspects associated with the manufacture of mono and multifunctional acrylate monomers.
Design/methodology/approach
This paper reviews commercially important UV cure mono and multifunctional acrylate monomers. It covers their synthesis, catalyst, and appropriate solvents for azeotropic removal of byproducts. The detail discussion on catalysis, basis of design of reactors and commercial plant and the process engineering associated with the manufacture has been supported through citation of synthesis of various acrylate monomers. The methodologies adopted for determination of physical, chemical and compositional characterisation of acrylate monomers have been presented. In addition, the guidelines regarding the bulk storage and commercial handling of acrylates have been reviewed.
Findings
The reaction engineering of esterification reaction between acrylic acid and polyol has been worked out to provide the basis for selection of reactors. The reaction has been modeled as a series – parallel complex reaction for providing explanation for generation of various byproducts/adducts and multiple esters.
Practical implications
The detailed discussion on formation, characterisation and treatment of Michael adducts and purification of acrylate monomers will be relevant for new researchers for further development. A review of guidelines on selection of homogenous and heterogeneous catalysts for synthesis of acrylate monomers has been presented.
Originality/value
Since the related literature on acrylate monomers is scarce, scattered and proprietary, the consolidated coverage in one paper will be useful.
Details
Keywords
Galal H. Elgemeie, Magdy K. Zahran, Emam M. Abbas and Ebtissam A. Abdel Mowla
Several new methylsulfanylpyrazolopyrimidines and methylsulfanylpyrazolotriazine derivatives containing an arylazo function were obtained. The application and characteristics for…
Abstract
Several new methylsulfanylpyrazolopyrimidines and methylsulfanylpyrazolotriazine derivatives containing an arylazo function were obtained. The application and characteristics for the synthesised dyes are demonstrated.
Details
Keywords
M.H. Helal, G.H. Elgemeie, M.A. El‐kashouti and K.A. El‐zaher Ahmed
The purpose of this paper is to synthesise new heterocyclic disperse azo dyes based on benzothiazapine moiety and their printability on synthetic fabrics.
Abstract
Purpose
The purpose of this paper is to synthesise new heterocyclic disperse azo dyes based on benzothiazapine moiety and their printability on synthetic fabrics.
Design/methodology/approach
Ethyl cyanoacetate was refluxed with aniline derivatives for 3 h to form cyanoacetanilides which coupled with different diazonium salts. The products obtained were cyclised with 2‐amino thiophenol to form arylazo benzothiazapine derivatives. The structures of the new dyes were characterised by micro‐analysis as well as IR, 1H NMR and 13C NMR. Printing pastes containing the dyestuffs prepared and thickened with sodium alginate were used for printing synthetic fabrics using either transfer printing or traditional screen printing.
Findings
New heterocyclic monoazo dyes derived from benzothiazabine moiety were obtained by the coupling of diazotised aniline derivatives with ethylcyanoacetate anilides followed by cyclisation with 2‐amino thiophenol. The use of synthesised dyes for transfer‐ or screen‐printing polyester and nylon 6 fabrics has been studied. The synthesised dyes which contain electron withdrawing substituents (NO2) in the phenyl ring attached to the azo groups and electron‐donating (OCH3) group on the other phenyl ring exert a bathochromic effect.
Research limitations/implications
Synthesis of azo dyes containing benzothiazapine moiety has never been reported in textile printing.
Practical implications
Production of simple and less costly dyes.
Originality/value
Synthesis of aryl azo benzothiazapine dyes by a simple method and application in printing of synthetic fabrics.
Details
Keywords
G.H. Elgemeie, K.A. Ahmed, E.A. Ahmed, M.H. Helal and D.M. Masoud
The purpose of this paper is to synthesize some novel 2-amino-6,6-dimethyl-9-phenyl-3-(phenyldiazenyl)-6,7-dihydropyrazolo-[5,1-b]quinazolin-8(5H)-one derivatives by…
Abstract
Purpose
The purpose of this paper is to synthesize some novel 2-amino-6,6-dimethyl-9-phenyl-3-(phenyldiazenyl)-6,7-dihydropyrazolo-[5,1-b]quinazolin-8(5H)-one derivatives by multi-component one-pot reaction using a microwave as a new tool for green chemistry.
Design/methodology/approach
An equimolor from arylazopyrazole, 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and benzaldehyde derivatives was dissolved in Dimethylformamide (DMF) to be irradiated in a microwave for 15 minutes; after completion of the reaction, as indicated by Thin layer chromatograph (TLC), the reaction mixture was poured into ice water, filtered and then crystallized with an appropriate solvent.
Findings
The structure of the synthesized dyes was established and confirmed for the reaction products on the basis of their elemental analysis and spectral data (MS, IR and 1H-NMR). These prepared dyes were used to print polyester and polyamide fabrics using synthetic thickener in the printing paste for the silk screen technique. The synthesized dyes are superior in terms of yield, purity, color strength and fastness properties and will lead to valuable achievements for commercial production.
Originality/value
An efficient method for synthesis of pyrazoloquinazolinone dyes was designed. The novel procedure features short reaction time, moderate yields and simple workup. The authors studied its application in printing polyester and polyamide fabrics.
Details
Keywords
The synthesis of novel cycloalkane ring‐fused arylazopyrazolo[1,5‐a]pyrimidines, using 4‐arylazo‐3‐aminopyrazol‐5‐ones as starting components, is described in this paper. The…
Abstract
The synthesis of novel cycloalkane ring‐fused arylazopyrazolo[1,5‐a]pyrimidines, using 4‐arylazo‐3‐aminopyrazol‐5‐ones as starting components, is described in this paper. The dyeing application and the dyeing characteristics of the dyes synthesised are also reported.
Details
Keywords
M.H. Helal, G.H. Elgemeie and D.M. Masoud
This paper aims to synthesize some new heterocyclic disperse azo dyes and their application in dyeing of polyester and polyamide fabrics.
Abstract
Purpose
This paper aims to synthesize some new heterocyclic disperse azo dyes and their application in dyeing of polyester and polyamide fabrics.
Design/methodology/approach
Pyrazolopyrimidine derivatives containing arylazo function by the reaction of 3,5‐ diaminopyrazole with ketene dithioacetals were prepared. The prepared dyestuffs are established using elemental analysis, IR measurements, 1H‐NMR and Mass spectra.
Findings
2,5‐diamino‐3‐arylazo‐N‐aryl‐6‐carboxamide‐7‐methylthio‐pyrazolo[1,5‐a]pyrimidine have been synthesized by the simple method. The dyed fabrics have a very good (4‐5) to excellent (5) results toward washing, perspiration, and rubbing fastness properties. The dyes are superior in terms of preparation and fastness properties.
Research limitations/implications
The disperse azo dyes used in this paper were synthesized via a step‐wise pathway leading to the new azo dyes. In addition, the variations in substituents and sites of location on the heterocyclic moiety could also be studied.
Practical implications
The new azo dye systems based on substituted pyrazolopyrimidine provided a series of azo dyes with improved dyeing properties. The dyes are superior in terms of yield, purity, colour strength, and fastness properties and will lead to valuable achievements for commercial production.
Originality/value
The synthesized disperse azo dyes are superior in terms of preparation, yield, purity, and fastness properties.
Details
Keywords
Galal H. Elgemeie, Maher H. Helal and Kawther A. Ahmed
Several new condensed carbocyclic arylazopyrazolo[1,5‐a]pyrimidine derivatives were obtained from 4‐arylazo‐3,5‐diaminopyrazoles as starting components. The application and dye…
Abstract
Several new condensed carbocyclic arylazopyrazolo[1,5‐a]pyrimidine derivatives were obtained from 4‐arylazo‐3,5‐diaminopyrazoles as starting components. The application and dye characteristics for the synthesized dyes are demonstrated.
Details
Keywords
M. Abdel Rehim, H.M. Fahmy, Z.E. Mohamed, M.H. Abo‐Shosha and N.A. Ibrahim
The purpose of this paper is to show how to remove some dyestuffs, as pollutants, from their aqueous solutions.
Abstract
Purpose
The purpose of this paper is to show how to remove some dyestuffs, as pollutants, from their aqueous solutions.
Design/methodology/approach
To achieve the goal, a water soluble hyperbranched poly (ester‐amide) (HBP) was synthesised using the melt polycondensation method by the reaction of maleic anhydride (MA) and diisopropanol amine (DIPA) at 140°C at a molar ratio of 1:1.3 MA: DIPA, respectively. This HBP was incorporated in the preparation of an effective microcrystalline cellulose (MCC)/dimethyloldihydroxyethylene urea (DMDHEU)/HBP adduct by crosslinking HBP with DMDHEU in presence of MCC. Furthermore, the prepared adduct was characterised by investigation its infra red and then utilised in the removal of three anionic dyestuffs from aqueous solutions, namely Irgalan Blau 3GL (an acid dye), SIRIUS Blau S‐BRR (a direct dye) and Levafix Brill Orange P‐GR (a hydrolysed reactive dye).
Findings
The results obtained revealed that the optimum conditions for preparing MCC/DMDHEU/HBP adduct are [HBP], 90 g/l; [DMDHEU], 200 g/l; LR, 1/3.3; [NC4LH], 20 g/l; a time of 30 min and a temperature of 160°C. Moreover, the results also showed that the extent of removal of such dyestuffs from their aqueous solutions by the prepared adduct follows the order: reactive dye>acid dye>direct dye, it is more pronounced at lower than at higher pH values and the removal of each dye by that adduct follows a first‐order reaction.
Research limitations/implications
Other substrates such as chitosan can be used to prepare more effective adducts.
Practical implications
Hyperbranched polymers can be used effectively to prepare ion exchangers capable of removing the pollutants of dyestuffs from their aqueous solutions.
Originality/value
The aforementioned prepared HBP is a novel hyperbranched polymer and could be applied in the removal of many other pollutants.
Details
Keywords
Copper‐clad polyimide glass laminates that pass the GPY/Polyimide Specifications of IPC‐L‐108A have been developed using the Michael reaction of bismaleimide and m‐aminophenol…
Abstract
Copper‐clad polyimide glass laminates that pass the GPY/Polyimide Specifications of IPC‐L‐108A have been developed using the Michael reaction of bismaleimide and m‐aminophenol. The addition reaction of m‐aminophenol to N‐phenylmaleimide has been confirmed from NMR, IR, and ultimate analysis. The peel strength of copper‐clad laminates is 1·8–2·0 kg/cm. The coefficient of expansion in the Z direction (25°C–246°C) is 0·96%. The glass transition temperature with post‐curing for an hour at 250°C is about 295°C. Water absorption by IPC‐L‐108A is 0·25%.
Regina Ngozi Ugbaja, Beno Okechukwu Onunkwor, Emmanuel Ifeanyichukwu Ugwor, Kunle Ogungbemi, Anuoluwapo Adewole, Michael Ayobami Olowoyeye, David Arowojolu, Olamide Yewande Adeleke and Victory Chukwudalu Ugbaja
This study aims to scrutinize the efficacy of chitosan (CT) on cardio-lipotoxic responses elicited by a high-fat diet (HF).
Abstract
Purpose
This study aims to scrutinize the efficacy of chitosan (CT) on cardio-lipotoxic responses elicited by a high-fat diet (HF).
Design/methodology/approach
Thirty-six male Wistar rats were distributed across six groups (n = 6): normal diet (ND), HF, ND-5%CT, HF-1%CT, HF-3%CT and HF-5%CT, for seven weeks. Blood and cardiac tissues were processed for biochemical, immunohistochemical and histopathological analyses.
Findings
Ingestion of HF induced hyperlipidaemia and lipid accumulation, leading to increased body and heart weight by 70.5% (p < 0.0001) and 124% (p = 0.0021), respectively, compared to ND-groups. Cardiac damage markers (creatine kinase, lactate dehydrogenase and malondialdehyde) were higher in the HF-group compared to control rats. Also, atherogenic and coronary risk indices were significantly elevated by 155% (p = 0.0044) and 174% (p = 0.0008), respectively, compared to control rats. Rats fed HF had significantly reduced cardiac antioxidants (superoxide dismutase, catalase and glutathione peroxidase) and elevated expression of NF-κB-p65 and p53 (p < 0.0001) in the cardiac tissues. Histology revealed lipid inclusions in the cardiac tissues of HF-groups. CT (1%–5%) prevented hyperlipidaemia, lipid accumulation, oxidative stress and cardiac damage in HF-fed rats, while greatly improving the histology of the cardiac tissues in HF-fed rats in a dose-dependent manner.
Originality/value
To the best of the authors’ knowledge, this is the first report of the effects of CT against cardio-lipotoxicity elicited by HF diet ingestion. The findings suggest that CT may present a safe therapeutic alternative for managing complications arising from cardio-lipotoxicity.
Details