Synthesis of and photodegradation in a series of poly(ethylene terephthalate)–co–4,4′-sulfonyldibenzoate yarns

Phototendering studies of poly(ethylene terephthalate) homopolymer yarn and a series of poly(ethylene terephthalate–co–4, 4′-sulfonyldibenzoate) copolymer yarns have shown that photosensitized degradation occurs more readily in the copolymers than in the homopolymer. A photo-oxidative mechanism involving the second monomer, dibutyl 4, 4′-sulfonyldibenzoate, has been proposed to account for the photosensitization. The photophysical processes in the second monomer, dibutyl 4, 4′-sulfonyldibenzoate, were studied by absorption and luminescence techniques. The lowest excited singlet and triplet in this compound were identified as the ¹(π, π^*) and ₃(π, π^*) states, respectively. The energy levels in the second monomer have been assigned as follows: ¹S₁ ～ 33,000 cm^?1, ¹S₂ ～ 42,000 cm^?1, and ³T₁ ～ 26,000 cm^?1.     

Stereochemistry of Neolignans - A Revised Structure for a Neolignan Isolated from the Roots of Piper capense

The erythro8-O-4′ neolignan IIIb was synthesized and was found to have identical ¹H and ¹³C NMR characteristics to a neolignan reported as a component of the roots of Nardostachys jatamansi. The NMR spectral characteristics of compound IIIb were also identical with those of a neolignan previously obtained from the roots of Piper capense, for which the unlikely 8-O-3′ structure IVa had been proposed. Two further erythro 8-O-4′ compounds IIIc and IIId were prepared, and their assigned ¹³C NMR signals were consistent with those of IIIb. At this time, there appears to be no evidence for the existence of 8-0-3′ neolignans as plant extracts.     

Synthesis and colour spectroscopic investigation of some hemicyanine dyes

New hemicyanine dyes with a benzo[2,3‐b;2′,3′‐b′]bis‐furo[3,2‐d]pyrazolium nucleus were prepared. Spectroscopic investigations were carried out in 95% ethanol for all the synthesised cyanine dyes and/or in pure solvents which have different polarities for some selected dyes. Structural identification was carried out via elemental analysis, infra‐red and proton nuclear magnetic resonance spectral data.     

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.     

Synthesis of a Magnetic Co@C Material via the Design of a MOF Precursor for Efficient and Selective Adsorption of Water Pollutants

3D metal–organic frameworks (MOFs) can be appropriate templates for the fabrication of nanomaterials due to they have active sites exposed on the channel or surface, which thus provide them with improved catalytic performance. In this study, a 3D cobalt-based MOF [Co(H₂bpta)]_n (Co-MOF), where H₄bpta denotes 2,2′,4,4′-biphenyltetracarboxylic acid, has been constructed with the use of a ligand with a high carbon content. On this basis, a 2D magnetic carbon-coated cobalt nanoparticle composite (Co@C) was prepared by using the title MOF under different temperatures. Magnetic Co@C can readily absorb dye from the solution and can thus act as an inexpensive and fast-acting adsorbent. Moreover, we have explored the adsorption isotherms, kinetics and thermodynamics of the anion dyes in detail. The adsorption capacity of the Co@C-800 for investigated methyl orange (MO) and congo red (CR) dyes were 773.48 and 495.66 mg g^?1, respectively. It is noteworthy that MO adsorption is higher in existing materials. Thermodynamic studies suggest that the adsorption processes are spontaneous and exothermic. This study opens a new insight into the synthesis and application of carbon-based materials that enable the selective removal of organic dyes.

Graphical Abstract

A Co-MOF has been solvothermal synthesized and structurally characterized, which was used as a combined catalyst and carbon source for the synthesis of magnetic Co@C. Interestingly, the as-grown Co@C-800 exhibits high-performance selective adsorption of anionic dyes (MO and CR) with high adsorption capacities.

     

Adsorption of phenazine dyes using poly(hydroxamic acid) hydrogels from aqueous solutions

Swelling and adsorption properties of poly(hydroxamic acid), (PHA) hydrogels in aqueous solutions of some phenazine dyes such as Neutral Red, Safranin T, and Janus Green have been investigated. PHA hydrogels containing N,N′ methylenebisacrylamide or ethyleneglycoldimethacrylate were used in experiments on swelling, diffusion and adsorption of the dyes. The equilibrium swelling (S_eq) values of PHA hydrogels in aqueous solutions of the phenazine dyes were calculated as 2.16–33.25 g g^?1. Swelling kinetic parameters such as initial swelling rate, swelling rate constant, and maximum swelling were found. Dye diffusion into hydrogels was found to be non‐Fickian in character. Diffusion coefficients are ranged 1.32 × 10^?6 cm² s^?1 ? 44.70 × 10^?6 cm² s^?1. Adsorption of the phenazine dyes onto PHA hydrogels was studied by batch technique. PHA hydrogels in the phenazine dye solutions showed the dark coloration. The data was found that Freundlich isotherm model fits. According the Freundlich constants, the adsorption isotherms are of S‐type in Giles classification. All swelling and binding parameters for PHA‐EGDMA were found to be higher than those for PHA‐NNMBA. The type of crosslinker influenced the swelling, binding, and sorption more than the type of dye. Finally, it can be said that PHA hydrogels may be used a sorbent for removal of dyes. POLYM. ENG. SCI., 58:310–318, 2018. © 2017 Society of Plastics Engineers     

Synthesis of novel amino(alkylamino)deoxychitins and the adsorption behavior of acid dye onto the resulting polymers

Novel chitin‐based materials were synthesized and the adsorption behavior of typical acid dyes to the resulting polymers has been evaluated. The successful synthetic reaction was confirmed by the infrared spectroscopic measurements. By the reaction of alkalichitin with tosyl chloride, the corresponding tosylchitin was synthesized as a soluble and reactive precursor. Next, aminodeoxychitin was synthesized by the reaction of the tosylchitin with ammonia. Similarly, 2′‐aminoethylamino‐ and 6′‐aminohexylaminodeoxychitins were synthesized by reacting the tosylchitin with ethylenediamine and hexamethylenediamine, respectively. It has been confirmed that the adsorption abilities of these polymers for acid dyes were significantly high, and also that one of the aminodeoxychitins showed a high adsorption ability for Cu²⁺ ion. On the basis of the adsorption data of acid dye on the aminodeoxychitin, the tosylchitin and the original chitin, the amino group contents at C₆ and C₂ positions were estimated. The aminodeoxychitin and aminoalkylaminodeoxychitins could be applicable to the adsorbent for anionic dyes and Cu²⁺ ion along with a precursor for further novel derivatives. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Cyanine dyes of new heterocyclic ring systems: Synthesis and structure-spectra studies

New cyanine dyes including monomethine cyanine dyes (simple cyanine dyes) and trimethine cyanine dyes (carbocyanine dyes) incorporating benzo[2,3-b; 2′,3′-b′]bispyrazolo[4,5-b]-1,4-(oxa-, thia-, and pyra)-zine-6,12-dione were prepared. Structure-spectra studies were carried out via measuring the electronic visible absorption spectra of these dyes in 95% ethanol. Structural confirmations were determined through elemental analysis, IR, ¹H NMR spectroscopy and MS spectral data at the Micro Analytical Center, Cairo University.     

Chitosan intercalated montmorillonite: Preparation, characterization and cationic dye adsorption

Chitosan intercalated montmorillonite (Chi-MMT) was prepared by dispersing sodium montmorillonite (Na⁺-MMT) into chitosan solution at 60 °C for 24 h. The Chi-MMT was characterized by XRD, XRF and FT-IR. The intercalation was accomplished via the ion-exchange of Na⁺ ions with –NH₃⁺ of chitosan, resulting in the expansion of d₀₀₁ from 1.42 nm of Na⁺-MMT to 2.21 nm of Chi-MMT. The chitosan content in the Chi-MMT measured by TGA was about 17 mass%. The adsorption capacity of Chi-MMT was investigated in comparison with the starting Na⁺-MMT and chitosan using three different cationic dyes, i.e. basic blue 9 (BB9), basic blue 66 (BB66) and basic yellow 1 (BY1). The Chi-MMT showed the highest adsorption capacity in the range of 46–49 mg/g when the initial dye concentration was 500 mg/L, being equivalent to 92–99 wt.% of dye removal. The adsorption capacities of Chi-MMT for all basic dyes increased with an increase of initial dye concentration. An increase of adsorption capability of Chi-MMT was attributed to the existence of intercalate-chitosan. It could enlarge the pore structure of Chi-MMT, facilitating the penetration of macromolecular dyes, and also electrostatically interact with the applied dyes. These results indicated the competency of Chi-MMT adsorbent for basic dye adsorption.     

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.     

A rhodamine B-based colorimetric chemosensor for sensitive and selective detection of Cu2+: Test strip analysis and density functional theory

We designed a rhodamine B-based colorimetric chemosensor BHSO ((Z)-3′,6′-bis(diethylamino)-2-(2-(((8-hydroxy-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-9-yl)methylene)amino)ethyl)spiro[isoindoline-1,9′-xanthen]-3-one) for detecting Cu²⁺. In the presence of Cu²⁺, BHSO caused a colour variation from colourless to bright orange. The limit of detection for Cu²⁺ towards BHSO was 0.73 μM. The binding of BHSO to Cu²⁺ was analysed as a 1:1 ratio through a Job plot and electrospray ionisation mass spectrometry. BHSO can detect readily Cu²⁺ with a test strip by colorimetric variation. The detecting process of Cu²⁺ by BHSO was represented by ultraviolet-visible titration, electrospray ionisation mass spectrometry, proton nuclear magnetic resonance titration, Job plot and density functional theory calculations.     

Some quantitative studies on light fading of after-treated direct dyes

Quantitative measurements of increase in lightfastness of direct dyes on cellophane on after-treatment with different metallic salts, e.g. sulphates of copper, cobalt, nickel, chromium and (ferrous) iron have been carried out. Copper sulphate has been found to be the best of all these salts. About 2% copper sulphate is found to cause considerable increase in the lightfastness. Measurements of y/x ratios of dyed and after-treated cellophane and also slopes of CF curves have shown that the higher fastness is due to higher aggregation of the dye in the fibre on after-treatment with copper sulphate. Metal complex formation with dye structures of the type o-hydroxy-o′-methoxy (or o′-hydroxy or ethoxy) azo has been found to be more useful for copper after-treatment than complex formation with dyes with a salicylic acid residue.     

Synthesis and characterization of a novel oligosiloxane containing alternative ladderlike structure via charge‐transfer interaction

A novel oligosiloxane containing alternative ladderlike structure involving viologen groups has been prepared via donor–acceptor interaction‐assisted template polymerization. The monomer used as the electron‐donor component, N,N ′‐bis(3‐methyldimethoxyl‐silylpropyl)‐4,4′‐bipyridinium dihexafluorophosphate and its precursor, N,N ′‐bis(3‐methyldimethoxyl‐silylpropyl)‐4,4′‐bipyridinium dibromide were first synthesized successfully in high yield. This oligosiloxane, which displays interesting electrochromic properties, has been characterized by FTIR, UV–vis, ¹H NMR, ²⁹Si NMR, X‐ray diffraction (XRD), and vapour pressure osmometry (VPO). © 2001 Society of Chemical Industry     

Substituted benzylidene Cyanines

Eight new chain substituted benzylidene cyanine dyes have been prepared by condensing 4-dimethylamino-2′-nitrobenzophenone and 4-dimethylamino-3′,5′-dinitrobenzophenone H90 H90 V 3 with methiodides of quinaldine and 6-haloquinaldines, in H90 H90 V 3 absolute ethanol, using piperidine as a basic catalyst. The optical absorption and H90 H90 V 3 extra sensitisation data of the dyes have been recorded and compared with those H90 H90 V 3 of their methin analogues. H90 H90 V 3The dyes absorb at longer wavelengths than their unsubstituted analogues, contrary to earlier observations. The dyes obtained from the 2′-nitroketone are H90 H90 V 3 good sensitisers, whereas those obtained from the 3′,5′-dinitroketone, are densensitisers. H90 H90 V 3     

The influence of molecular weight of acid dyes on the yield stress of dyed nylon monofilament

The yield stress of nylon filament dyed with several acid dyes has been determined as a function of dye content and the molecular weight of acid dyes. The nylon filament dyes with acid dye has greater yield stress than undyed one. The relation between the increment of the yield stress (f) due to the adsorption of acid dye and the dye content (C) in the filament can be expressed by parameters A and B as log f = A log(C ? _C) + B, where C₀ is the dye content under which no contribution to the yield stress is observed and C₀ depends on the number of sulfonic groups in acid dye. It is found that these parameters A and B are expressed by M (the difference between the molecular weight of acid dye and the weight of SO₃Na groups in it) as A = 1 ? 100/M, B = k₁ M^k2, where k¹ and k² are the constants which depend on the parent chemical structure of dyes. The parameters A and B are expected to give available informations as to the physical state of adsorbed dye on nylon filament.     

Solubility of Two Disperse Dyes Derived from <Emphasis Type="Italic">N</Emphasis>-Alkyl and <Emphasis Type="Italic">N</Emphasis>-Carboxylic Acid Naphthalimides in the Presence of Gemini Cationic Surfactants

The solubility of naphthalimide-based monoazo dyes containing N-ethyl and N-ethanoic acid groups was investigated in the presence of a conventional monomeric counterpart (DTAB) and two cationic gemini surfactants (12-4-12 or 14-4-14) individually. The effective parameters on dye solubility such as temperature, time and concentration of surfactants were investigated by UV–Visible spectrophotometry. The results demonstrate that the solubility of both dyes was considerably increased at concentrations above the surfactant CMC. The wavelength for the maximum absorbance of dyes in the aqueous solution shifts toward longer wavelengths with changes in the concentration of the cationic surfactants. A kinetic study of solubilization of dyes in cationic surfactants solution showed that the rate of solubilization follows the pseudo-first-order reactions. Rates of solubilization were in the range of 0.5 × 10⁻³ to 6.8 × 10⁻³ min⁻¹ for both dyes. The disperse dye containing a carboxylic acid group (dye 2) has a higher solubility rate than the dye containing an alkyl group (dye 1). The type of surfactant has a very low effect on adsorption of dye 1 onto the polyester fibers, whereas changing the surfactant type from DTAB to 12-4-12 or 14-4-14 causes adsorption of dye 2 on polyester to decrease.     

Research on the Chroming of Diacromo Dyes

An attempt has been made to reduce the dyeing time with afterchrome dyes by eliminating the cooling step before afterchroming. This cooling is normally necessary to control the rate of chroming to obtain level dyeings. Other methods of control have been investigated, including the use of chromium fluoride rather than potassium dichromate. Triphenylmethane dyes containing salicylic acid groups can be chromed with chromium(III) at the boil, giving a brighter dyeing and a lower rate of chroming than when dichromate is employed. Salicylic acid azo and some oo′-dihydroxyazo dyes can also be chromed with chromium(III) compounds, but the colours produced differ greatly from those obtained when dichromate is used. With other afterchrome dyes, such as oo′-dihydroxyazo dyes, that have additional substituted or unsubstituted hydroxy] or amino groups capable of interaction with dichromate, the mechanisms of chroming with chromium(III) and chromium(VI) are different.     

Synthesis of some new unsymmetrical aza-pyrazolomonomethine cyanine dyes

New aza-pyrazolomonomethine cyanine dyes IV and V have been prepared by the condensation of some nitroso compounds, namely p-nitroso-N,N′-dimethyl or diethyl aniline, α-nitroso-β-naphthol and β-nitroso-α-naphthoI, with known unsymmetrical pyrazolomonomethine cyanines II and III . The u.v. and visible spectra of all dyes prepared have been investigated.     

Chemical fixation of disperse dyes on protein fibers

Chemical fixation of disperse dyes on protein fibers has been examined in non-aqueous dyeing media. Disperse dyes that contained amino group within a molecule had high potential to react with protein fibers. Selection of dyeing medium gave marked influence on the dyeability of dyes on fibers. 4-(Dimethylamino)-pyridine (DMAP) and N,N′-dicyclohexylcarbodiimide (DCC) were also examined as auxiliaries for acylation and dehydration, respectively. Effects of DMAP on the reaction between disperse dyes and protein fibers were higher than that of DCC.     

Studies on the Vilsmeier-haack reaction. Part XIII: Novel heterocyclo-substituted 4,4′-bi-pyrazolyl dithiocarbamate derivatives

5-Imino-3-methyl-l-phenyl-2-pyrazoline-4-dithiocarbamic acid (I) underwent simultaneous formylation and dimerization reactions with the Vilsmeier reagent giving 4-[5′-imino-3-(1″-formyl-2″-dimethylaminoethenyl)-3′-methyl-1′-phenyl-1′H-pyrazolo-4′-dithiocarbamyl-2,4-dihydro-3-imino-5-methyl-2-phenyl-1-pyrazoline]dithiocarbamate (II) which hydrolysed with sodium hydroxide to give 4-[3′-(1″-formyl-2″-hydroxyethenyl)-3′-methyl-1-phenyl-1′-H-pyrazolo-4′-dithiocarbamyl-1′-pyrazoline]dithiocarbamate-5,5′-dione (IV). Treatment of II and/or IV with morpholine, piperidine, piperazine, hydroxylamine, hydrazine hydrate or phenylhydrazine afforded the corresponding dipyrazolo-4,4′-dithiocarbamate derivatives with different heterocyclic systems at the 3-position. The structures of these compounds were confirmed by microanalysis data, IR and ¹H-NMR spectrometry. All synthesized compounds have been screened in vitro against Gram-positive and Gram-negative bacteria, and fungi.