Synthetic resins. XVIII. Chelation ion exchange properties of 2,4-dinitrophenylhydrazone of 4-hydroxy acetophenone–formaldehyde resins

A large number of copolymers were synthesized by condensing 2,4-dinitrophenyl hydrazone of 4-hydroxy acetophenone (4HA 2,4 DNPH) with substituted benzoic acids/phenols and formaldehyde in the presence of NaOH or HCl as catalyst. The resins were characterized by IR spectra. The decomposition temperature, solubility parameter, and viscositv of the polymers have been determined. The ion-exchange properties have been studied using the batch equilibrium method. The measurement of the distribution of a given metal ion between an aqueous solution and the resins has been performed. The investigation was carried out over a wide range of pH and varying the ionic strength of the medium. © 1992 John Wiley & Sons, Inc.     

Synthetic resins: I. Preparation and characterization of resins from substituted benzoic acid–formaldehyde

A number of resins have been prepared by the condensation of substituted benzoic acid with formaldehyde in the presence of different acids and bases as the catalyst. The intrinsic viscosity and Huggin's and Kraemer's constants of the resins were determined. The solubility behavior of the resins was studied. The IR spectra and the thermogravimetric analysis of the resins were also studied. The values of the energy of activation of degradation of the resins were computed by using the Freeman–Anderson method.     

Synthetic resins: XV. Chelation ion exchange properties of 2,4- dinitrophenylhydrazone of resacetophenone-formaldehyde resin

A number of copolymers were synthesised by condensing the 2,4-dinitrophenylhydrazone of resacetophenone with substituted benzoic acids/ phenols and formaldehyde in the presence of sodium hydroxide or hydrochloric acid. The decomposition temperature, solubility and viscosity of the polymers have been determined. The ion-exchange properties have been studied by using a batch equilibrium method. The distribution of a number of metal ions between an aqueous solution and the resin have been measured. A wide range of pH and variable ionic strengths have been investigated.     

Synthetic resins. XIII. Synthesis and characterization of the resins derived from quinacetophenone/substituted benzoic acid/furfuraldehyde

Some resins have been synthesized by reacting quinacetophenone with substituted benzoic acids and furfuraldehyde in the presence of basic catalysts. The resins have been characterized by IR spectra of the characteristic groups. The number average molecular weights of the resins have been evaluated by the conductance method. The solubility and viscosity behaviors of the resin copolymers have been determined. Cu⁺², Ni⁺², Co⁺², Mn⁺², and Mg⁺² chelates have been prepared. The resins were shown to be selective ion-exchange resins for certain metal ions. A batch equilibrium method was used for studying the selectivity of the metal ions. The thermal behavior of the resins has been determined and the values of energy of activation of the resins were computed by using the Freeman–Anderson and Broido methods. The biological assays of some of the resin copolymers were found to be highly sensitive.     

Synthesis and characterization of novel sulfobetaines derived from 2,4‐tolylene diisocyanate

Novel sulfobetaines were synthesized from two urethanes derived from 2,4‐tolylene diisocyanate (TDI) blocked with 2‐hydroxyethyl methacrylate (HEMA) and either N,N‐dimethylaminopropylamine (DMAPA) or N,N‐dimethylaminoethanolamine (DMAEA). The first‐stage reaction of TDI with HEMA was carried out in petroleum ether heterogeneously with the precipitation of the intermediate monoadduct product in the reaction solution. The second stage is a homogeneous reaction of the monoadduct with the blocking agent, DMAPA or DMAEA, in tetrahydrofuran (THF). In both reactions, an inhibitor, hydroquinone, and a catalyst, dibutyltin diacetate (DBDAc), were used. The tertiary amine urethanes were quaternized by 1,3‐propane sultone to form the two novel sulfobetaines. The results of the elemental analysis of those products along with their ¹H‐NMR and IR spectra indicated that these materials were, indeed, the compounds expected. The products dissolved in strongly polar organic solvents. The copolymerization of these two monomers with comonomers such as styrene, methyl methacrylate, acrylamide, and HEMA was investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3447–3459, 2001     

Resin I: Synthesis,characterization, and ion‐exchange properties of terpolymer resins derived from 2,4‐dihydroxypropiophenone,biuret, and formaldehyde

Terpolymers (2,4‐DHPBF) were synthesized by the condensation of 2,4‐dihydro‐xypropiophenone, biuret, and formaldehyde in the presence of acid catalyst with varying the molar ratio of reacting monomers. Terpolymer composition has been determined on the basis of their elemental analysis and their number–average molecular weight of these resin were determined by conductometric titration in nonaqueous medium. The viscosity measurements were carried out in N,N‐dimethyl formamide which indicate normal behavior. IR spectra were studied to elucidate the structure. The terpolymer resin has been further characterized by UV–visible and ¹H‐NMR spectra. The newly synthesized terpolymers proved to be selective chelating ion‐exchange terpolymers for certain metals. The chelating ion‐exchange properties of this terpolymer was studied for Fe (III), Cu (II), Hg (II), Cd (II), Co (II), Zn (II), Ni (II), and Pb (II) ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurement of the distribution of a given metal ion between the terpolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The terpolymer showed a higher selectivity for Fe (III), Hg (II), Cd (II), and Pb (II) ions than for Cu (II), Co (II), Zn (II), and Ni (II) ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of surface-active compounds derived from cholesterol derivatives and glucose

The synthesis and characterization of surface-active compounds based on various steroid derivatives and glucose are presented. The hydrophobic and hydrophilic parts of the compounds were linked via glucosidic bonds. All compounds were found to have very low water solubility and only limited solubility in various organic solvents. The compounds were investigated according to their ability to interact with an anionic surfactant, sodium dodecylsulfate (SDS), in order to induce a decrease in the critical micelle concentration (CMC) of the surfactants. This synergistic effect was pronounced for cholestanol-6-on-β-D-glucopyranoside and for cholestan-3,6-diol-β-D-glucopyranoside. These two compounds lowered the CMC from 8 to 6 and 0.6 mM, respectively, for water solutions of SDS/glucoside with a molar ratio of 92∶8. Furthermore, the ability of the compounds to stabilize lipid membranes, in liposomes, at varying concentrations of Ca²⁺, was studied. The compounds were, as expected, found to induced stabilization similar to that of cholesterol.     

2,4-二氨基甲苯、尿素和甲醇合成甲苯-2,4-二氨基甲酸甲酯反应精馏过程研究

甲苯-2,4-二氨基甲酸甲酯(TDC)是非光气合成甲苯二异氰酸酯(TDI)的重要中间体,2,4-二氨基甲苯(TDA)、尿素和甲醇一步合成TDC是一条绿色的反应工艺。今在反应精馏装置上研宄了操作条件对非催化合成TDC反应的影响,得出适宜操作条件为:反应温度190°C,压力0.7~0.75 MPa,反应原料分为两股进料,其中一股进料为TDA,尿素和甲醇的混合液(nTDA:/nUrea:nMeOH=1:5:80),进料位置为反应段上方,速率为0.3 m L·min-1,另一股为纯甲醇,进料位置在反应段下方,速率为5.0m L·min-1,塔顶回流比0.75,塔釜釆出比90:2。在该条件下,TDA的转化率62%,TDC的收率和选择性分别为36%和58%。与高压釜上所得结果相比,TDC的选择性提高了17%。     

Synthetic resins. XX. Chelation ion exchange properties of resins derived from semicarbazone of 2-hydroxy acetophenone-substituted benzoic acid–formaldehyde

A number of resins have been synthesized by reacting orthohydroxy acetophenone-semicarbazone with substituted benzoic acid and formaldehyde in the presence of some acid and basic catalyst. The physicochemical properties of the resins have been reported. The ion exchange properties of the resins have been investigated. Influence of electrolytes on the metal uptake of Cu²⁺, Ni²⁺, Zn²⁺, Mg²⁺, and Mn²⁺ has been studied. The distribution of metal ions at different pH has also been reported. © 1992 John Wiley & Sons, Inc.     

Clarification of a wheat straw‐derived medium with ion‐exchange resins for xylitol crystallization

BACKGROUND: Xylitol bioproduction from lignocellulosic residues comprises hydrolysis of the hemicellulose, detoxification of the hydrolysate, bioconversion of the xylose, and recovery of xylitol from the fermented hydrolysate. There are relatively few reports on xylitol recovery from fermented media. In the present study, ion‐exchange resins were used to clarify a fermented wheat straw hemicellulosic hydrolysate, which was then vacuum‐concentrated and submitted to cooling in the presence of ethanol for xylitol crystallization. RESULTS: Sequential adsorption into two anion‐exchange resins (A‐860S and A‐500PS) promoted considerable reductions in the content of soluble by‐products (up to 97.5%) and in medium coloration (99.5%). Vacuum concentration led to a dark‐colored viscous solution that inhibited xylitol crystallization. This inhibition could be overcome by mixing the concentrated medium with a commercial xylitol solution. Such a strategy led to xylitol crystals with up to 95.9% purity. The crystallization yield (43.5%) was close to that observed when using commercial xylitol solution (51.4%). CONCLUSION: The experimental data demonstrate the feasibility of using ion‐exchange resins followed by cooling in the presence of ethanol as a strategy to promote the fast recovery and purification of xylitol from hemicellulose‐derived fermentation media. Copyright © 2008 Society of Chemical Industry     

Terpolymer resin II: Synthesis,characterization, and ion‐exchange properties of 2,4‐dihydroxyacetophenone–dithiooxamide–formaldehyde terpolymers

Terpolymers have been prepared by the condensation of 2,4‐dihydroxyacetophenone (2,4‐HA) and dithiooxamide (D) with formaldehyde (F) in the presence of hydrochloric acid as catalyst with varying the molar proportions of the reactant. Compositions of the terpolymer have been determined by elemental analysis. The number average molecular weight has been determined by conductometric titration in nonaqueous medium. Intrinsic viscosities of the solution of the terpolymer have been determined in N,N‐dimethyl formamide (DMF). The terpolymers have been characterized by UV–visible, IR, and proton NMR spectra. Chelation ion‐exchange properties have also been studied employing the batch equilibrium method. It was employed to study selectivity of metal ion uptake over a wide pH range and in media of various ionic strength. The overall rate of metal uptake follows the order: Fe³⁺ > Cu²⁺ > Ni²⁺ > Co²⁺ = Zn²⁺. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of a new class of thermosetting resins: Allyl and propargyl substituted cyclopentadiene derivatives

A series of all-hydrocarbon resins were synthesized by reacting cyclopentadiene allyl chloride, propargyl chloride, or a mixture of allyl chloride and propargyl ide, under phase transfer conditions. Phase transfer reactions with and without added solvents, and with either quaternary ammonium or crown ether catalysts, yielded similar products consisting of a mixture of 1,1-disubstituted cyclopentadiene (minor amount) and 2-3 isomers each of tri-, tetra-, penta-, and hexa-substituted derivatives. No further reaction of each these components possible. The overall substitution pattern varied little with changes in reaction conditions although limiting the allyl chloride content led to still reactive, partially substituted products. Incorporation of all-propargyl and high propargyl-to-allyl mixed functionalities on cyclopentadiene yielded products whose stability was very hindering their thorough characterization. Preliminary evaluation was there-carried out for mixed resins with lower propargyl functionality. The allyl substituted resin (allylated cyclopentadiene, ACP) underwent thermal cure lout initiator at around 200°C while allyl/propargyl substituted resin (7:1 ratio, APCP) showed a faster, lower temperature cure at around 120°C. Cationic cure of ACP was also initiated by a novel sulfonium salt at around 100°C. Neat resin when cured at 200°C gave material with a flexural storage modulus 2 of about 300 MPa. Further cure at 250°C raised the modulus to 1.2 GPa. resin gave composites with excellent properties when used with glass and on fibers. Flexural modulus values (by DMA) of ∼ 66 GPa were obtained for ACP/carbon fiber composites compared with 42 GPa for epoxy/carbon composites made in our laboratories using commercially available materials. The modulus values at 300°C dropped to 10% of the room temperature value for the epoxy composites, while the ACP/carbon composite maintained 60% of its room temperature value at 300°C. When brought back to ambient temperature, the modulus of latter sample had increased to 80 GPa and that of the epoxy composite dropped to 23 GPa. Glass fiber ACP composites performed similar to an epoxy composite up to 200°C but maintained properties up to 300°C while those of the epoxy were drastically reduced. TGA analysis of both cured ACP resin and its composites showed decomposition beginning at 375°C. Three-point-bending tests indicated very high modulus with brittle failure for ACP composites. Scanning electron micrographs showed moderate bonding of the new resin to both carbon glass fiber surfaces. This new class of thermosetting resins offers excellent potential for application in low-cost glass and carbon composites with good thermal and physical properties.     

Polymers from renewable resources. V. Synthesis and characterization of thermosetting resins derived from cashew nut shell liquid (CNSL)–furfural-substituted aromatic compounds

A number of resins were synthesized by reacting cardanol, a byproduct of the cashew industry, with furfural and substituted aromatic compounds in the presence of acid and basic catalysts. The resins were characterized by IR and NMR spectra and shown to be selective ion exchangers for certain metal ions. A batch equilibrium method was used for studying the selectivity of the metal ions. The thermal behavior of the resins was also studied. A plausible degradation mechanism is suggested. © 1994 John Wiley & Sons, Inc.     

Adsorption and photocatalytic degradation of phenol and 2,4 dichlorophenoxiacetic acid by Mg–Zn–Al layered double hydroxides

Mg–Zn–Al layered double hydroxides (LDHs) with varying amounts of zinc were prepared by the coprecipitation method. Solids were analyzed by XRD and N₂ physisorption, confirming the formation of pure LDH phase; and the production of mixed oxides with high specific surface areas (182–276 m² g⁻¹) after calcination. Band gap energy was also determined, presenting the expected decreasing tendency on increasing zinc amounts. These mixed oxides were tested both for the adsorption of 2,4 dichlorophenoxiacetic acid (2,4-d) and for the photocatalytic degradation of 2,4-d and phenol. Nearly total (97%) degradation of initial 1.45 mmol L⁻¹ of 2,4-d, with 1 g calcined LDH per liter, was accomplished in 9 h, while phenol half-life was as short as 3.5 h, with the catalyst with lowest zinc amount (5 wt.%). Langmuir adsorption isotherms are presented. Solids were also characterized by XRD and FTIR analysis after photocatalytic and adsorption activity, to determine the presence of 2,4-d. The versatility of LDH decomposition products in the elimination of different contaminants by different mechanisms puts them forward as a viable alternative for environmental remediation.     

Chelation ion‐exchange properties of copolymer resin derived from 4‐hydroxyacetophenone,oxamide, and formaldehyde

A copolymer (4‐HAOF) prepared by condensation of 4‐hydroxyacetophenone and oxamide with formaldehyde in the presence of an acid catalyst proved to be a selective chelating ion‐exchange copolymer for certain metals. Chelating ion‐exchange properties of this copolymer were studied for Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺, Pb²⁺, and Hg²⁺ ions. A batch equilibrium method was employed in the study of the selectivity of metal‐ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for Fe³⁺ ions than for Co²⁺, Zn²⁺, Cd²⁺, Pb²⁺, Cu²⁺, Ni²⁺, and Hg²⁺ ions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 787–790, 2003     

Elimination of inorganic mercury from waste waters using crandallite‐type compounds

The removal of inorganic mercury from waste water streams arising from mines, using an artificial amorphous compound of the crandallite type synthesized in our laboratory, Ca_0.5Sr_0.5Al₃(OH)₆(HPO₄) (PO₄), has been investigated. This compound exhibits an extremely wide range of ionic substitutions: Ca²⁺ and Sr²⁺ were interchanged with Hg²⁺, so the mercury content of the waste water, ranging from 70 to 90 ppm, was reduced to less than 0.1 ppm. The process has been studied under batch conditions. The crandallite showed a high capacity for the exchange of mercury from mercuric nitrate solutions, 1.555 meq g^?1. The ion‐exchange equilibrium isotherms for Hg²⁺ were correlated by the Langmuir equation. The recovery of mercury from Hg‐crandallite using HCl solutions and thermal treatment was also studied. Optimum recuperation of mercury is achieved by chemical reaction with HCl solution (pH 2.25). At these conditions, 75% of the mercury is recovered as the HgCl₄^2? complex in a simple batch process, and the crandallite (in the protonic form) can be reused. © 2003 Society of Chemical Industry     

Copolymers of acrylic acid with 2‐acryloyloxyethyl 2,4‐dichlorophenoxyacetate: Synthesis and herbicide release

Free‐radical copolymerization of acrylic acid with 2‐acryloyloxyethyl 2,4‐dichlorophenoxyacetate using 1.0 mol/L 1,4‐dioxane solution and 1.5 × 10^?2 mol/L of 2,2′ azobisisobutyronitrile as initiator has been carried out at 50°C. In addition to low conversion solution experiments performed to estimate the monomer reactivity ratios, three different copolymerizations over the whole range of conversions have been made. Theoretical values of cumulative copolymer composition, determined by the Mayo‐Lewis terminal model, have been correlated with those experimentally obtained. Finally, the herbicide release in three different aqueous pH buffer solutions has been evaluated in heterogeneous phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4238–4244, 2006     

Adsorption of 2,4-D on Mg/Al–NO3 layered double hydroxides with varying layer charge density

Layered double hydroxides (LDHs) have high surface area and high anion exchange capacity, so they have been proposed to be an effective scavenger for contaminants. In this study, the adsorption of 2,4-dichlorophenoxyacetate (2,4-D) on Mg/Al–NO₃ LDHs with varying layer charge density was investigated with particular attention on the effect of the orientation of the interlayer nitrate. Three Mg/Al LDHs were synthesized with Al³⁺/(Al³⁺ + Mg²⁺) molar ratios of 3.3 (LDH3), 2.6 (LDH4) and 2.1 (LDH5). The results of adsorption experiments showed that LDH5 exhibited an S-type isotherm with a low 2,4-D adsorption capacity due to the low accessibility of 2,4-D to the interlayer space. The accessibility was restricted by the small basal spacing of LDH5 as a result of the parallel orientation of the interlayer nitrate with respect to the hydroxide sheet. Thus, the 2,4-D adsorption occurred mainly on the external surface of the material. On the contrary, LDH3, which has the highest layer charge density among the samples, contains nitrate with an orientation perpendicular to the hydroxide sheet of LDH3. The interlayer nitrate was readily exchanged by 2,4-D. Thus, in addition to the adsorption on the external surface, the replacement of the interlayer nitrate by 2,4-D contributed to a higher adsorbed amount of 2,4-D; the 2,4-D adsorption of LDH3 exhibited an L-type isotherm. For LDH4 that contained interlayer nitrate with both parallel and perpendicular orientations, the adsorption characteristics were between those of LDH3 and LDH5. This work has demonstrated the dependence of 2,4-D adsorption characteristics on the nitrate orientation in LDHs, as a consequence of changing layer charge density.