Presence Of Manganese Acetate Research Articles

Synthesis and Characterization of Oligomer Bis(<i>trans</i>-2,3-dibromo-4-hydroxy-2-butenyl)terephthalate as a Green Corrosion Inhibitor on Mild Steel in 1 M H<sub>3</sub>PO<sub>4</sub> Solution

Poly(ethylene terephthalate) (PET) waste was depolymerized by trans-2,3-dibromo-2-butene-1,4-diol in the presence of manganese acetate as a catalyst using microwave irradiation as opposed to the conventional heating process in order to reduce the time required for PET depolymerization. The depolymerization product bis(trans-2,3-dibromo-4-hydroxy-2-butenyl)terephthalate (BDBHBT) was isolated, characterized, and evaluated as a green inhibitor for mild corrosion steel in corrosive 1 M H3PO4 medium. This product was characterized using FTIR and 1H-NMR. The effects of immersion time, inhibitor concentration, and reaction temperature were studied. The chemical technique utilized in this study was weight loss, while the electrochemical technique employed an open circuit potential. With 0.6 g/L of BDBHBT inhibitor, the highest corrosion inhibition efficiency of 83.3% was observed. The kinetic and thermodynamic functions were calculated, and the results indicated that the investigated inhibitor was physically adsorbed on the surface and confirmed to the Langmuir adsorption isotherm. This study aims to lessen pollution of the environment by transforming PET waste to a beneficial oligomer BDBHBT and estimating the inhibitory effect of this product on the corrosion of mild steel in 1 M H3PO4.

OXIDATION OF ACETOXITOLUENES WITH MANGAN(III) ACETATE

The kinetics and mechanism of the reaction of ozone with acetoxytoluenes in an acetic anhydride solution in the presence of manganese acetate have been studied. The main reaction products under these conditions are hydroxybenzyl alcohols in the form of the corresponding acetoxybenzyl acetates (65-77%). The effect of manganese (II) acetate on the selectivity of oxidation with respect to the methyl group has been studied. The mechanism of redox catalysis is considered, which explains the obtained experimental data.

Green Recycling of Poly(ethylene terephthalate) Waste as Corrosion Inhibitor for Steel in Marine Environment

Green recycling of poly(ethylene terephthalate) plastic waste, in this respect, PET waste was subjected to de polymerization process with tri methylene glycol (1,3-propandiol) in the presence of manganese acetate (1.0 % w/w to the total Wight of the reactants) as trans esterification catalyst, the product is Bis-(3-hydroxy-propyl)-terephthalate, BHPT, as a non-ionic surfactant was separated and characterized by FT-IR and 1HNMR and evaluated as corrosion inhibitor for carbon steel alloy in artificial marine environment using chemical and electrochemical techniques. Effect of inhibitor concentrations and reaction temperature were studied. The chemical techniques used in this work are gravimetric, thermometric and atomic absorption spectroscopy(AAS), whereas the electrochemical techniques are open circuit potential, potentiodynamic polarization. The corrosion inhibition efficiency increases with increasing inhibitor concentrations and decreased by rising temperature. The maximum corrosion inhibition efficiency 96.5% was afforded using 300 ppm of the used inhibitor derived from plastic waste. Potentiodynamic polarization curves indicate that the used system act as mixed inhibitor. The data of AAS show that the iron(iii) ions Fe+3 concentrations were decreased by increasing inhibitor concentration. All the used techniques are in good agreement to each other (±2 %) and shows that the used drug acts as green corrosion inhibitors for steel in marine environment.

Green Synthesis for Nonionic Surfactants from Poly(etheleneterphthalate) Plastic Waste

ABSTRACT Efficient solvent free green glycolysis for Polyethylene Terephthalate plastic waste, in this respect, PET waste was subjected to depolymerization process with trimethylene glycol (1,3-propandiol) in the presence of manganese acetate as trans esterification catalyst, the product is Bis-(3-hydroxy-propyl)-terephthalate, BHPT, as a non-ionic surfactant was separated and characterized by FT-IR and 1HNMR, The surface properties were studied by measuring the surface tension at different concentrations and temperatures. The surface tension, critical micelle concentration (CMC), and surface activities were determined. The surface parameters such as surface excess concentration (rmax), the area per molecule at interface (Amin)and the effectiveness of surface tension reduction ( πCMC ) were determined from the adsorption isotherms of the prepared surfactant. The thermodynamic data for the micellization and adsorption process were calculated and discussed.

Solvent Free Glycolysis of Plastic Waste as Green Corrosion Inhibitor for Carbon Steel in Sulfuric Acid

Solvent free efficient green glycolysis of Polyethylene terephthalate waste, PET, in this respect, PET waste was subjected to depolymerization with propylene glycol in the presence of manganese acetate as a catalyst, the product is Bis-(3-hydroxy-propyl)-terephthalate, BHPT, as non-ionic surfactant was separated, characterized by FT-IR and 1HNMR, BHPT was evaluated as corrosion inhibitor for steel in the presence of 1.0 M sulfuric acid by chemical and electrochemical methods, the corrosion inhibition efficiency increase with inhibitor concentration and decrease with temperatures, the galvanostatic polarization curves indicate that the BHPT, compound act as mixed inhibitor, the impedance of the inhibited solution has increased with the increase in the concentration of the inhibitor. the inhibition due to adsorption of the inhibitor molecules on the steel surface, the adsorption obey Langmuir adsorption isotherm. Thermodynamic parameters were computed and discussed, Scanning electron microscope (SEM) was used to study the surface morphology of steel in absence and presence of the used inhibitor, hydrogen evolution techniques was used to evaluate the inhibition efficiency of the BHPT inhibitor compound. the data obtained from different techniques are in good agreement to each other and show the BHPT, surfactant derived from PET, waste considered as good corrosion inhibitor for steel in sulfuric acid.

Statistical Process Optimization of Functionalized PET Oligomer Nanocomposites from Off-Grade PET

Off-grade Poly(ethylene terephthalate) (PET) of industrial manufacturers was partially depolymerized, using excess ethylene glycol (EG) in the presence of manganese acetate to synthesize PET oligomers. Influences of EG/PET molar ratio, reaction time, and catalyst concentrations and particle size of off-grade PET on yield of partial glycolysis reaction were investigated. The optimal conditions to synthesize PET oligomer (melting point of about 180°C) were obtained. Then, maleated PET as a compatibilizer for preparing PET nanocomposites was produced via reaction between maleic anhydride/phthalic anhydride (MA/PhA) composition and optimized PET oligomers. The combination of reaction time of 106 minutes and PhA/MA molar ratio of 0.85 gave the best results based on d-spacing and peak shift of nanocomposite samples. Hence, melt mixing of maleated PET with organoclay produced a good intercalation of layered silicate and good dispersion of clay in maleated PET matrix. Analysis of variance (ANOVA) was studied for both glycolyzed products and functionalized PET oligomers.

Recycling of off‐grade pet via partial alcoholysis to synthesize functionalized pet oligomer nanocomposites

AbstractOff‐grade poly(ethylene terephthalate) (PET) of industrial manufacturers was partially depolymerized using excess ethylene glycol in the presence of manganese acetate as a transesterification catalyst to synthesize PET oligomers. Influences of reaction time, Ethylene Glycol (EG)/PET molar ratio, catalyst concentrations, and particle size of off‐grade PET on yield of partial glycolysis reaction were investigated based on Box–Behnken's design of experiment. Thermal analyses of glycolyzed products are examined by differential scanning calorimetry. The optimum samples were also well‐characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (1H‐NMR and 13C‐NMR). The optimal conditions to synthesize PET oligomer (melting point of about 180°C) for a 120‐min glycolysis reaction time were EG/PET molar ratio of 2 with no catalyst using granule‐shaped PET. The same results were obtained for a 60‐min glycolysis reaction time, including EG/PET molar ratio of 1 with the weight ratio (catalyst to PET) of 0.5% using average particle size of PET. Then, maleated PET as a compatibilizer for preparing PET nanocomposites was produced via reaction between maleic anhydride/phthalic anhydride composition and optimized PET oligomers based on central composite design of experiment. The combination of reaction time of 106 min and PhA/MA molar ratio of 0.85 gave the best results based on d‐spacing and peak shift of nanocomposite samples. Hence, melt mixing of maleated PET with organoclay produced a good intercalation of layered silicate and good dispersion of clay in maleated PET matrix. Analysis of variance (ANOVA) was studied for both glycolyzed products and functionalized PET oligomers. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Porous polyurethane foams based on recycled poly(ethylene terephthalate) for oil sorption

AbstractIn using recycled poly(ethylene terephthalate) (PET) as a petroleum sorbent we tried to achieve two important objectives simultaneously. PET waste was glycolized using trimethylolpropane (TMp) or pentaerytheritol (PEr) to produce suitable polyol oligomers for polyurethane (PU) foams. The glycolysis was carried out in the presence of manganese acetate as a catalyst under normal pressure in m‐cresol at 220 °C. Producing polyols, PEr degraded PET into lower molecular weights than TMp. So prepared oligomers were reacted with 2,4‐toluene diisocyanate providing several types of PU foam. The effect of various variables (polyol reactivity, water content, type of catalyst, isocyanate amount and surfactant) on the foam structure and properties were analyzed. Porosity of the PU foams was examined using environmental scanning electron microscopy. Foams based on glycolized TMp contain small uniform cells whereas other foams form less uniform cells with varying sizes including closed cells. Dynamic mechanical analysis gives much lower storage moduli for TMp‐based PUs that for those based on PEr, an effect of dangling ethylene chains in the former case. The glass transition temperatures Tg are higher when PEr rather than TMp is used. Our PU foams show good sorption properties and sufficient reusability. Copyright © 2012 Society of Chemical Industry

Kinetics and mechanism of the catalytic reaction of ozone with toluene in the liquid phase

The kinetics and product composition of the liquid-phase catalytic oxidation of toluene with an ozone-air mixture were studied. It was shown that at low temperatures in an acetic anhydride medium in the presence of manganese acetate and an inorganic acid, oxidation develops mainly at the methyl group, yielding benzyl acetate, benzaldehyde, and benzylidene diacetate. The scheme of redox catalysis to explain the experimental data is discussed.

Poly(vinyl alcohol-co-lactic acid)/Hydroxyapatite Composites: Synthesis and Characterization

There is a wide range of applications where calcium phosphate and hydroxyapatite (HA) are used as biomaterials, e.g. as synthetic bone grafts, coating on metal prostheses (like hip endoprostheses or dental implants) and drug carriers. In the study, the design and synthesis of composites based on poly(vinyl alcohol-co-lactic acid)/hydroxyapatite (PVA-co-LA/HA) with potential for biomedical applications, they are presented. The hydroxyapatite particles were surface-grafted with l(+)-lactic acid in the presence of manganese acetate as catalyst, resulting in modified hydroxyapatite (HAm) with improved capacity of bonding, respectively for the preparation of the composite based on PVA-co-LA/HAm. FT-IR spectra further confirmed the existence of PLA polymer on the surface of HA particles. In synthesis of PVA-co-LA copolymer the different molar ratios PVA/LA (2/1, 1/1, 1/2), toluene/water: 1/2 (as azeotrope solvent mixture) and manganese acetate as catalyst, were used. The composite materials were synthesized in situ with 10 wt% HA, and respectively HAm (reported to PVA and lactic acid components). The composite materials were characterized by FTIR spectroscopy, thermal analyses (DSC, DTG), 1H-NMR spectroscopy, particle size distribution and zeta potential.

Synthesis of new cationic surfactants based on recycled poly(ethylene terephthalate) for deinking of solvent‐based ink from low‐density polyethylene surface

AbstractWater‐soluble oligomers based on poly‐(ethylene terephthalate) waste, PET, were prepared from transesterification of PET with diethanolamine and triethanolamine in the presence of manganese acetate as a catalyst at temperature of 200°C for 8 h. New cationic surfactants were prepared by reaction of the produced recycled oligomers with bromoacetic acid followed by quaternization with pyridine. The chemical structure of the prepared surfactants was confirmed by 1H‐NMR analysis. The surface tension, critical micelle concentration, and surface activities were determined at different temperatures. Surface parameters such as surface excess concentration (Γmax max), the area per molecule at interface (Amin), and the effectiveness of surface tension reduction (∏CMC) were determined from the adsorption isotherms of the prepared surfactants. The prepared surfactants were tested as ink removal for printed low‐density polyethylene surface. The effect of surfactants concentrations, pH, soaking time, and shaking time were investigated for deinking process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Synthesis and evaluation of a new water soluble corrosion inhibitor from recycled poly(ethylene terphethalate)

Polyethylene terephthalate waste (PET) was depolymerized by triethanolamine into glycolyzed product (GT), followed by esterification with bromacetic acid in the presence of manganese acetate as a catalyst to give (GT-Br). The obtained ester was reacted with thiourea to give thiol derivative (GT-SH). The effectiveness of the synthesized compound as corrosion inhibitor for API XL65 carbon steel, in 2 M hydrochloric acid solution was investigated by various electrochemical techniques such as open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of these investigations showed enhancement in inhibition efficiencies with the increasing of inhibitor concentration. The protective film formed on carbon steel surface was analyzed using an energy dispersive X-ray analysis (EDX) technique. Also, scanning electron microscope (SEM) was used to study the surface morphology of steel surface in the absence and presence of 400 ppm of the additive.

CORROSION OF CARBON-STEEL ALLOY IN 0.1M NITRIC ACID IN PRESENCE OF PLASTIC WASTE AS CORROSION INHIBITORS

Recyclization of poly (ethyleneterphthalate), (PET), with Diethanolamine and Triethanolamine having 1:2 wt% of PET: wt% of DEA or wt% TEA, in presence of manganese acetate as a catalyst. The inhibition action of the prepared compounds (D2 & T2) on the corrosion of carbon-steel which used in the manufacture of petroleum pipelines in nitric acid was evaluated, at different concentrations of inhibitors from (50-250 ppm) at different temperatures, ranged from (303-333 K). The polarization curves indicate that these compounds may act as mixed-type inhibitors. The adsorption of the prepared compounds on C-steel was found to follow the Langmuir adsorption isotherm,they also obey El-Awady isotherm. The values of activation energies (Ea*) and all thermodynamic activation parameters which determined, indicating that the type of adsorption was chemical adsorption.

New epoxy resins based on recycled poly(ethylene terephthalate) as organic coatings

Glycolysis of poly(ethylene terephthalate), PET, waste using trimethylol propane (TMP), triethanolamine (TEA), diethylene glycol (DEG) and diethanolamine (DEA) was used to produce suitable hydroxy-oligomers for epoxy. The glycolyzed products were reacted with epichlorohydrine to prepare a series of di- and tetraglycidyl epoxy resins with different molecular weights. The glycolysis was carried out in presence of manganese acetate as a catalyst at normal and high pressure in presence and absence of xylene at 210 °C. The produced resins were cured with different mole ratios of 1-(2-amino ethyl) piprazine as curing agent at room temperature. The mechanical properties of the cured epoxy resins were evaluated. The chemical resistances of the cured resins were evaluated through salt spray resistance, hot water, solvents, acid and alkali resistance measurements. The data indicate that the cured epoxy resins based on glycolyzed oligomer of PET and DEA have excellent chemical resistances as organic coatings among other cured resins.

Synthesis of Rigid Polyurethane Foams from Recycled Poly(ethylene Terephthalate) Waste

Glycolysis of poly(ethylene terephthalate), PET, waste using trimethylol propane (TMP) or pentaerytheritol (PEr) was used to produce suitable hydroxyoligomers for polyurethane foams. The glycolysis was carried out in the presence of manganese acetate as a catalyst, under high and normal pressure atmosphere in xylene and m-cresol at 220 °C. The prepared oligomers were reacted with 2,4- 2,6- toluene diisocyanate to produce different types of polyurethane foams. The compressive and flexural strengths, open and closed cell%, oxygen index% and curing times were determined and the results were correlated to the chemical structure of the produced oligomers.

Mechanical characteristics of modified unsaturated polyester resins derived from poly(ethylene terephthalate) waste

AbstractThe depolymerization of poly(ethylene terephthalate) (PET), by an alcoholysis reaction is an easy operation and gives prospects for the utilization of wastes. PET waste was first depolymerized by glycolysis reaction at three different molar ratios of diethylene glycol (DEG), in the presence of manganese acetate as a transesterification catalyst. Copolyesters of PET modified with varied mole ratios of p‐hydroxybenzoic acid (PHBA) were reported to exhibit excellent mechanical and chemical properties due to their liquid crystalline behaviour. Here we study the effect of incorporating (PHBA) units into the building structures of different unsaturated polyesters synthesized originally from glycolysed PET waste. Modified unsaturated polyesters were synthesized by depolymerizing PET with DEG, and the obtained oligoesters were reacted with PHBA and maleic anhydride (MA). The molar ratio of the added PHBA was varied to investigate its effect on the mechanical characteristics of these modified unsaturated polyesters. The data obtained reveal that increasing the molar ratio of PHBA within the studied range of concentrations leads to a pronounced improvement in the mechanical characteristics, which is represented mainly by the values of/maximum compression strength (σmax) and Young's modulus (EY).© 2002 Society of Chemical Industry

Synthesis of (�)-cis-tetradec-5-en-4-olide ? The racemate of the sex pheromone of the Japanese beetle

A three-stage method has been developed for the stereoselective synthesis of (±)-cis-tetradec-5-en-4-olide — the racemate of the sex pheromone of the Japanese beetlePopillia japonica C. The key reactions used were the stereoselective cis reduction of a triple bond with the aid of heterogeneous hydrogenation catalysts (zinc-copper couple, nickel boride, Lindlar catalyst) and the radical lactonization of conjugated systems by the action of acetic acid in the presence of manganese acetate.

RNA polymerase activity associated with bacteriophage phi 6.

The Pseudomonas phaseolicola bacteriophage phi6 incorporated labeled UTP into an acid-insoluble precipitate. Incorporation was dependent on the presence of manganese acetate, ATP, GTP, CTP, and a short heat treatment of the phage; the reaction was stimulated by NH(4)Cl. The substitution of (14)C-ATP, -CTP or -GTP for UTP, together with the appropriate unlabeled ribonucleoside triphosphates, disclosed that CMP was incorporated to the greatest extent followed by GMP, UMP, and AMP. Radioactive RNAs formed by the reaction were resistant to RNases A and T(1) in high salt but susceptible to these nucleases in low salt. The labeled RNA co-sedimented and co-electrophoresed with phi6 double-stranded (ds) RNA. However, the distribution of the radioactivity into the three ds-RNA components varied depending on the (14)C-ribonucleoside triphosphate used in the reaction. The incorporation of UMP was primarily into the two smaller ds-RNA segments, GMP primarily into the large ds-RNA segment, and CMP and AMP were about equally distributed into all three ds-RNA segments.

Absorption of oxygen by 2‐ethylhexaldehyde

AbstractThe kinetics of absorption of oxygen by 2‐ethylhexaldehyde dissolved in 2‐ethylhexanoic acid at concentrations up to 1.38 × 10−3 mole/cm3 (20 wt.‐%), in the presence of manganese acetate, was studied in a stirred cell and in bubble and packed bubble columns. Diffusion of oxygen was found to play a major role. The reaction was first order in oxygen and second order with respect to the aldehyde, and the overall third‐order rate constant was found to be 2.98 × 107 cm6 mole−2 sec−1 at 30°. The effect of cobaltous acetate on the specific rate of absorption of oxygen was also studied and manganese acetate was found to be the better catalyst.

Absorption of oxygen by n‐butyraldehyde

AbstractThe kinetics of absorption of oxygen by n‐butyraldehyde dissolved in n‐butyric acid, in the range of concentrations up to 3·1 × 10−3 gmole/cm3 (25 wt.‐%), in the presence of manganese acetate, was studied in stirred cells and a bubble column. It was found that diffusion of oxygen is important. The reaction was found to be first‐order in oxygen and second‐order with respect to the aldehyde. The overall third‐order reaction rate constant was found to be about 4 × 106 (cm3/gmole)2 sec−1 at 20°. The effect of the catalysts, cobaltous acetate and (cobaltous + 4 cupric) acetates, on the specific rates of absorption of oxygen was also studied. Manganese acetate was found to be the best catalyst.