Hours Of Reaction Time Research Articles

OPTIMIZATION OF COCOA BUTTER EQUIVALENT PRODUCTION FROM FORMULATED HARD PALM OIL MID-FRACTION AND CANOLA OIL BLENDS

The study to find cocoa butter equivalent (CBE) as an alternative to cocoa butter (CB) from available and low cost commercial oils or fats has been increased recently. Current study investigates the blending of hard palm oil mid-fraction (PMF) with canola oil to produce high nutritional CBE using immobilized lipase from Rhizomucor miehei. The experiments were designed using Response Surface Methodology (RSM) to optimize the percentage of saturated-unsaturated-saturated (StUSt) triacylglycerols (TAGs). The experiment was performed at hard PMF concentration of 50 to 90% (w/w), lipozyme load between 5% and 10% (based on the weight of substrate) with a reaction time between 2 to 14 hours. The best reaction conditions to attain this target was 89.35% (w/w) of hard PMF concentration, 2 hours of reaction time, and 5% (based on the weight of substrate) of lipozyme load, resulting CBE which contains 64.44±1.18% of StUSt. The addition of canola oil improved the nutritional value of CBE which was marked by the higher percentage of linoleic acid (omega-6, 4.53±0.06%) and linolenic acid (omega-3, 0.74±0.14%) in CBE than CB (omega-6, 2.68±0.34%). Enzymatic interesterification was not altering fatty acid content in the CBE, especially linoleic acid (omega-6) and linolenic acid (omega-3) which was characterized by no significant difference (p > 0.05) between the fatty acid profile of initial mixture (before interesterification) and CBE (after interesterification).

Facile Hydrothermal Synthesis of Molybdenum Disulfide (MoS2) as Advanced Electrodes for Super Capacitors Applications

ABSTRACTA facile hydrothermal method was used to synthesize molybdenum disulfide (MoS2) microspheres. The effect of hydrothermal reaction time on morphology and electrochemical properties of MoS2 microspheres was evaluated. X-ray diffraction showed presence of crystalline MoS2 structure, where content of crystalline phase was observed to increase with hydrothermal reaction time. Electrochemical properties of MoS2 were evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge in 3M KOH solution. Specific capacitance of nanostructured MoS2 was observed to be between 68 F/g and 346 F/g at different scan rates along with excellent cyclic stability. High power density (∼1200 W/kg) and energy density (∼5 Wh/kg) was observed for MoS2 sample synthesized for 24 hours of hydrothermal reaction time. Overall optimal electrocapactive performance was observed for sample prepared for 24 hours of reaction time. It is demonstrated that the obtained MoS2 microspheres with three-dimensional architecture has excellent electrochemical performances as electrode materials for supercapacitor applications.

Preliminary studies on immobilization of lipase using chicken eggshell

A few advantages of enzyme immobilization are reusability of expensive enzyme, improvement of stability and activity compared to crude enzyme. Various organic components can be used as carrier for enzyme immobilization such as chicken eggshell. It can be used as a carrier for immobilization as its mineral component mostly contains of calcium carbonate. In the present study, Tributyrin method was used to test enzyme activity of Rhizomucour Miehei, Candida Antarctica and Candida Rugosa. Rhizomucour Miehei shows the highest enzyme activity (360.8 mol/min/mL lipase) and was used in further experiment. Experiment was continued to study incubation time for lipase immobilization on eggshell (1-4 hours) and reaction time of esterification of sugar ester (0-72 hours). Two hours incubation time for lipase immobilization was observed and gives the highest yield of sugar ester (78.13%). Fructose and stearic acid as substrate was used for the production of sugar ester. The highest percentage of sugar ester production was shown at 36 hours of reaction time.

Phase-Selective Hydrothermal Preparation and Upconversion Luminescence of NaYF<sub>4</sub>:Yb<sup>3+</sup>,Tm<sup>3+</sup>

Upconversion luminescence materials have been proved to have a good efficiency on converting low energy light to high energy light. These materials have received considerable attentions for many applications such as bio-labels, sensors, using for developing solar cells and photocatalytic applications under sunlight. Among many inorganic host materials, NaYF4 has been proved to be the best for doping lanthanide ions and have a good upconversion emission due to its low phonon energy, chemical stability, and transparency in the near infrared to ultraviolet range. In this study, NaYF4:Yb3+,Tm3+ upconversion luminescence materials were synthesized by hydrothermal method at temperature of 90 to 200 °C for period between 1 to 24 hours. The synthesized NaYF4:Yb3+,Tm3+ were characterized by X-ray diffraction, scanning electron microscopy, and fluorescence spectroscopy. The hydrothermal temperature and reaction time have strongly influence on phases and upconversion emission of the synthesized NaYF4:Yb3+,Tm3+. At 90 °C for 1 hour of reaction time, the pure cubic phase of NaYF4:Yb3+,Tm3+ was found. After increasing temperature and reaction time, the NaYF4:Yb3+,Tm3+ converted from cubic phase to hexagonal phase. Under excitation of 980 nm diode laser, the hexagonal NaYF4:Yb3+,Tm3+ exhibited the emission wavelength at about 656 nm (3F2 → 3H6), 469, 492, 552 nm (1G4 → 3H6), 537 nm (1D2 → 3H5), 450, 461 nm (1D2 → 3F4), 362 nm (1D2 → 3H6) and 345 nm (1I6 → 3F4). The upconversion emission intensity of the hexagonal NaYF4:Yb3+,Tm3+ was much stronger, compared with that of the cubic NaYF4:Yb3+,Tm3+.

Ultrasonic-Assisted Galvanic Replacement Synthesis for the Platinum Deposition on Palladium to Prepare Pd-Pt/MWCNT Electrocatalysts for ORR

In this work a simple two step method for preparing bimetallic Pd-Pt/MWCNT electrocatalysts via ultrasonic-assisted galvanic-replacement is presented. Firstly, Pd nanoparticles were deposited over MWCNT by micro-emulsion method to synthesize Pd/MWCNT. In a second step the Pd/MWCNT electrocatalyst is immersed in an ultrasonic bath of an aqueous solution containing different Pt concentrations to form a bimetallic Pd-Pt/MWCNT electrocatalyst by galvanic replacement reaction. It is worth to mention that any additive reagent was added during this reaction. The effects of galvanic replacement time, temperature and agitation were investigated. Three different amounts of Pd content were tested: 5, 10 and 20% wt. The catalysts were characterized by TEM, EDS and electrochemical methods. The results showed that bimetallic nanoparticle composition can be tuned up through the galvanic replacement conditions, where the Pt concentration of solution has a very important role. The ultrasound conditions allowed a great performance of the galvanic replacement reaction which leads to achieve the best electrocatalyst in two hour reaction time at room temperature. The electrocatalyst prepared with 10% wt of initial Pd content, 2 hour of reaction time, Pt concentration of 1.25 mM and final composition of Pd:Pt 1:2 showed the highest catalytic activity of all synthesized catalysts. These results showed a simple, efficient an environmental friendly route to synthesized bimetallic electrocatalysts for fuel cell applications.

EPOXIDATION SYNTHESIS OF LINOLEIC ACID FOR RENEWABLE ENERGY APPLICATIONS

Monoepoxidation linoleic acid (MEOA) has advantages for industrial applications. MEOA was synthesized using immobilized Candida antarctica lipase (Novozym 435). At optimum conditions, higher yield (82.14 %) and medium oxirane oxygen content, OOC (4.91 %) of MEOA were predicted at 15 μL of H2O2, 120 mg of Novozym 435 ® and 7 hours of reaction time. Fourier Transform Infrared Spectroscopy (FTIR) spectra of the MEOA showed monoepoxide group at 820 cm. H NMR analysis confirmed the monoepoxide group at 2.92 – 3.12 ppm while the monoepoxide signals of C NMR appear at 54.59 – 57.29 ppm. LC-MS analysis shows that of MEOA gives m/z at 296.22 as final product. MEOA exhibited good pour point (PP) of -41 oC. Flash point (FP) of MEOA increased to 128 oC comparing with 115 oC of linoleic acid (LA). In a similar fashion, viscosity index (VI) for LA was 224 generally several hundred centistokes (cSt) more viscous than MEOA 130.8. MEOA was screened to measure their oxidative stability (OT) which was observed at 168 oC. It is evident that increasing the hydrogen peroxide amount has a strong effect on the reaction kinetics; however, a large excess of hydrogen peroxide results in accumulation of peracid in the final product.

Biosynthesis and characterization of gold nanoparticles using extracts of tamarindus indica L leaves

This study reports the biosynthesis of gold nanoparticles using an extract of Tamarindus indica L. leaves. Phenols, ketones and carboxyls were present in the leaves of T. indica. These organic compounds that allowed the synthesis of nanoparticles were identified by gas chromatography coupled to mass spectrometry (GC/MS) and High Pressure Liquid Chromatographic (HPLC). Synthesis of gold nanoparticles was performed with the extract of T. indica leaves and an Au+3 aqueous solutions (HAuCl4) at room temperature with one hour of reaction time. Characterization of gold nanoparticles was performed by UV visible spectroscopy, scanning electron microscopy (SEM) and EDX. The results indicated the formation of gold nanoparticles with a wavelength of 576nm and an average size of 52±5nm. The EDX technique confirmed the presence of gold nanoparticles with 12.88% in solution.

On-site rapid detection of toxic Alexandrium tamiyavanichii: integrating the species-specific hydrolysis probe in insulated isothermal polymerase chain reaction (iiPCR)

On-site investigation of phytoplankton samples is important for rapid detection of harmful algal species and for early warning of harmful algal bloom. Molecular detection method by DNA amplification in a portable insulated isothermal PCR (iiPCR) device provides a simple and rapid detection based on fluorescent probe within an hour of reaction time. The assay was developed for a paralytic shellfish toxin-producing dinoflagellate Alexandrium tamiyavanichii. The assay presents the data as positive or negative on the presence or absence of A. tamiyavanichii cells, with a limit of detection (LOD) at five target cells per reaction. While the assay is incapable to accurately quantify cell density, it exhibits high detection accuracy and strongly correlated with quantitative PCR (qPCR) data. The user repeatability of iiPCR assay was evaluated; the results showed that no significant differences in the assay run by different operators. Field applicability of the assay was further validated by environmental samples. Despite the shortcoming of the assay, the overall performance of the assay to detect cells, its low-cost effectiveness, and portability for on-site detection, iiPCR has proven its potential as an early screening tool for harmful algae monitoring.

Synthesis and Characterization of Starch Vernolates in Organic Solvents

In this study the synthesis of epoxy fatty acid esters of starch (starch vernolates) by the reaction of cassava starch with vernonia oil methyl ester (epoxy ester) using basic catalyst K2CO3 and organic solvent, DMSO as a reaction medium is presented. Under current reaction conditions, a high degree of substitution of 1.24 was achieved, at a reaction temperature of 110°C and 12 hours of reaction time. The new starch vernolates were characterized by Scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated that the new product is an amorphous material with a continuous and shapeless morphology. The melting point measured by differential scanning calorimetry (DSC) was 118°C. The new synthetic method makes the synthesis of starch vernolates less time consuming and more inexpensive. The differences in melting point and degree of substitution with previously synthesized starch vernolates using enzymatic and chemical catalysis suggest a difference in reaction selectivity via this new reaction path.

Degradation of Indigo Carmine Using Advanced Oxidation Processes: Synergy Effects and Toxicological Study

The physicochemical degradation of Indigo Carmine (IC) dye in aqueous solution was performed using single and combined Advanced Oxidation Processes (AOP’s). Photocatalysis (TiO2-UV), Ozonation (O3) and Sonolysis (SN) were tested either in a standalone methodology or by combination of two simultaneous AOP’s. The dye conversion was followed by both measurements: 1) color removal determined by UV-VIS spectrometry and 2) organic and inorganic load determined by the chemical oxygen demand (COD). A complete and quick color disappearance of model water waste has been obtained by using combination of non-irradiated AOP’s, namely, O3/SN, which contrasts to the combination of irradiated photocatalysis with O3 or sonolysis. Color removal with simultaneous TiO2-UV/SN reached 77% while TiO2-UV/O3 reached 96% at similar reaction time. On the other hand, the standalone O3 yielded the highest color removal (94.4%) in 32 minutes whereas SN reached only 39.2% in 4 hours. The standalone light irradiated TiO2-UV reached 93.3% color re-moval in one hour of reaction time. These results indicated that non-irradiated (SN and O3) enhance synergistic effects that provoke structural changes in dye molecule without reaching total degradation. This is evidenced from FTIR of residuals from reaction mixture in which it has been observed the presence of organic molecules such as aromatics, sulfonic and amines refractory compounds that are mechanisti-cally possible to be found during IC degradation. Also, toxicity tests (MicroTox® Technique) were performed using commercially available bacteria culture before and after IC degradation for each AOP and their combination. Reduction of aqueous dye concentration decreased the level of toxicity of the treated water which is the main target of the AOP’s but the presence of the remaining recalcitrant compounds have also toxic effect.

Determination Optimum B2O3, KCl and NaOH Molar Ratios in the Synthesis of Potassium Borates

Borates are attention getting chemical compounds because of their properties which leads them a wide usage area. Being sub-group of borates, potassium borates show non-linear optical properties and owing to this they can find applications in optical modulation, optical switching, optical logic and memory, signal processing. Potassium borates can be used in welding, insulation, metal refining and lubricating oil production applications, also. In this study, potassium borates were produced from potassium chloride (KCl), sodium hydroxide (NaOH) and boron oxide (B 2 O 3 ) when different molar ratios of B 2 O 3 were used to find out the optimum ratio for the synthesis at 80°C and 1 hour of reaction time. The molar ratios of reactants were examined as 1:1:3 (as KCl:NaOH: B 2 O 3 ), 1:1:4, 1:1:5, 1:1:6 and 1:1:7. The identification of products and the effects of different molar ratios on the final product were determined by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) methods. According to experimental results, the Santite (KB 5 O 8 ·4H 2 O) mineral with powder diffraction file number (pdf) code of 01-072-1688 was produced for all molar ratios whereas the optimum ratios in which highest XRD score was obtained was 1:1:7.

Combination of electrocoagulation with advanced oxidation processes for the treatment of distillery industrial effluent

The treatment of distillery industrial effluent by means various combinations of electrocoagulation with Advanced Oxidation Processes (AOPs) such as ozonation, electrocoagulation, peroxi–electrocoagulation, photo–electrocoagulation, ozone–electrocoagulation and peroxi–photo–electrocoagulation process on the removal of percentage color, COD and energy consumption. The effects of various operating parameters such as ozone flow rate (5 to 15 LPM), initial effluent pH (2 to 10), current density (0.10 to 0.50A/dm2) and H2O2 concentration (50 to 500mg/L) on the removal of pollutant were studied in this study. Moreover comparison of all the processes in terms of color removal, COD removal and energy consumption was also carried out. The experimental results showed that100% of color and COD removal could be achieved by ozone–electrocoagulation process with an energy consumption of 5.7kWh/m3 within four hours of reaction time. The extent of color and COD removal was analyzed using a UV/vis spectrophotometer and closed reflux method.

Ranitidine abatement in chemically activated persulfate systems: Assessment of industrial iron waste for sustainable applications

This work assessed the use of industrial iron waste in the activation of persulfate (PS) (100μM) into sulfate radicals (SRs) for the removal of ranitidine (RAN) (28.5μM) from aqueous systems. The released iron corrosion products (ICPs) e.g. mainly Fe2+ species are responsible of PS activation. The optimal molar ratio of Fe2+:PS was found to be 1:1. A comparative study between industrial iron (iFe) and commercial iron (cFe) at 2 successive experimental runs showed that iFe has some advantages over cFe in terms of sustainability and less sludge formation. At low load of iFe (1mg/20mL), RAN removal was 95% over one hour of reaction time with a ratio of released Fe2+:PS of only 0.16:1.00. This system was evaluated at different ionic strength [I] conditions with NaClO4 neutral electrolyte, as well as in the presence of Cl- and Br-, the main seawater components. Results showed that at elevated [I] conditions, the rate of RAN degradation has decreased. However, in the presence of Cl- and Br-, with optimum levels of 1.0mM at [I]=100mM, RAN removal was enhanced rather than quenched. The total organic carbon (TOC) was analyzed at different PS:iFe molar ratios. Although degradation was successful at a very low iFe load, mineralization was negligible. However, RAN co-precipitation with in-situ formed ICPs improved TOC removal at higher iFe levels. The HPLC/MS chromatograms showed the presence of an oxidized RAN intermediate detected at 331m/z that dissipated gradually throughout the treatment.

English

Double promoted catalyst (CaO/KI/γ-Al2O3) was used as the catalyst for transesterification of palm oil into biodiesel. The experiment was carried out in a batch reactor consisting of a three-neck glass flask (500 ml capacity) equipped with a reflux condenser, thermometer and magnetic stirrer. Kinetic study was carried out with methanol under reflux conditions at different temperatures (35-75°C) and different times of reaction (1-7 hours). The effects of temperature and time of the reaction on the conversion of palm oil into biodiesel and reaction rate constants were investigated. The results showed that the conversion and rate constants of reaction increased with the increasing of the reaction temperature. The highest conversion of 97% was obtained at 65°C and 5 hours of reaction time. Meanwhile, the activation energy and the frequency factor were 15.47 kJ/mol and 1.22.10 2 , respectively.

Removal of malachite green in aqueous solution by adsorption on sawdust

A new adsorbent was synthesized from sawdust, a forest residue, in which methanol was used as a solvent and triethylamine as a modification agent under the following optimum conditions: 25 °C of reaction temperature, 1 : 8.75 of the ratio of sawdust to triethylamine (g:mL) and 1 hour of reaction time. The adsorption capacity of this adsorbent for malachite green was improved by 632.98% in contrast to that of the unmodified sawdust under the same adsorption conditions. Factors affecting the adsorption behavior of this adsorbent for malachite green, such as pH value, adsorption time, temperature and initial dye concentration, were evaluated through experiments in a batch system. The results indicated that the maximum adsorption capacity can be achieved at 5.08 of pH value and adsorption equilibrium can be reached in 6 hours. It was also found that the higher the temperature, the higher the adsorptive capacity would be. The Freundlich isotherm model provides a better description for the adsorption equilibrium when compared with the Langmuir equation in the conditions of the present study. Additionally, to examine the controlling mechanisms of the process, kinetic equations of the mass transfer and chemical reaction, the pseudo-first order model, the pseudo-second order model and the intraparticle diffusion model were used to correlate the experimental data respectively. The adsorption process of malachite green on sawdust tended to be controlled simultaneously by film mass transfer and intra-particle diffusion and it accompanied chemical reactions. It showed that the sawdust modified with triethylamine had good performance for cationic dye and can be used as a biomass adsorbent to treat dyes-containing wastewater with high quality.

Improving the yield of Jatropha curcas's FAME through sol–gel derived meso-porous hydrotalcites

The conversion of fatty acid methyl ester (FAME) from triglycerides using heterogeneous catalysis has gained increasing interest due to the prospect of increased yield at reduced operating costs and reaction conditions. In this paper, meso-porous hydrotalcite was used to catalyze jatropha oil into FAME with relatively higher yield at atmospheric pressure and relatively low reaction temperature. The molar ratio of methanol to oil required was relatively low and the conversion was completed within few hours of reaction time. The reaction was promoted when moderate calcination temperature was applied, the disordered structure of the catalyst was maintained, counterbalance anions was removed, and phase transitions within the oxide lattice was induced. Despite the observed deactivation during successive reaction cycles due to adsorption of residual triglycerides, the catalyst performance was restored effectively by air-re-calcination.

Disinfection byproduct formation kinetics of a water treatment plant on Kinmen Island

Chloramine has often been used as a chlorine alternative for trihalomethane (THM) and haloacetic acid (HAA) control. However, nitrogenous disinfection byproduct (N-DBP) formation and nitrification in distribution have always been major concerns in chloramination practices. On Kinmen Island, the high organic nitrogen content in raw water may increase the nitrogenous DBP formation. Simulated distribution system tests were conducted to explore the DBP formation kinetics in the distribution system. Lower haloacetonitrile (HAN4) formation (0.26 μg L−1) with chloramination than with chlorination (10.48 μg L−1) was observed from the 24 hours of reaction time. The nitrogen sources contributing to the dichloroacetonitrile (DCAN) formation kinetics were explored with 15N-chloramination. The results showed that nitrogen sourced from organic nitrogen was more dominant in DCAN formation with low chloramine dosage. This suggests that chloramine contributes to less DCAN formation in practice, especially for short distribution systems. In summary, the results provide evidence that simultaneous post-chloramination and pre-chlorination would be a feasible disinfection strategy applied to control regulated THM and HAA formation on Kinmen Island.

PENGARUH WAKTU REAKSI DAN RASIO MOL ASAM LINOLEAT DENGAN ISOPROPANOL PADA SINTESA PLASTISIZER ISOPROPIL LINOLEAT

Diversity of palm oil product in Indonesia is still limited, therefore it is needed to take an advantage of the development of downstream product of crude palm oil by esterification reaction. Esterification reaction is a reaction between carboxylic acid and alcohol to form ester. One of the emerging downstream product fatty acid alkyl ester is plasticizer. Plasticizer is an additive compound added to polymer to improve flexibility and workability. The purpose of this research was conducted to study the effect of reaction time and mole ratio and identify product of plasticizers isopropyl linoleic. In this research, plasticizer was synthesized by esterification of linoleic acid and isopropanol, using activated natural zeolite catalyst. The process was done with a variation of reaction time (4, 6, and 8 hours) and mole ratio (1: 6, 1: 9, and 1:12), with reaction temperature at 80 °C, stirring speed at 200 rpm and 15% of composition of linoleic acid based catalyst as fixed variables. From the analysis of the results showed that the esterification reaction time and mole ratio affect the product conversion. The best operating condition obtained in this research was 4 hours of reaction time and 1:12 of mole ratio which resulted the conversion of reaction was 67.09%. Characteristics of plasticizer produced from this research were viscosity (at 20 °C) 2.405 to 2.803 mPa.s and Specific Gravity (at 20 °C) from 0.863 to 0.872.

PENGARUH PELARUT TERT-BUTANOL TERHADAP MINYAK DAN SUHU REAKSI GLISEROLISIS PADA PEMBUATAN MONO DAN DIASILGLISEROL (MDAG) MENGGUNAKAN KATALIS ABU CANGKANG TELUR AYAM

Mono and diacylglycerol (MDAG) is one of the synthetic emulsifier agent widely used in food industry. Emulsifier agent is one of the economically high value oleochemical product. The purpose of this research is to produce MDAG through glycerolysis process of refined bleached deodorize palm oil (RBDPO) and glycerol by using egg shell waste as catalyst (4 % of oil weight) for 2 hours, whereas the variables ratio of tert-butanol to oil (1, 2, 3 v/w) and reaction temperatur (60, 70 and 80 oC). Egg shell waste was calcined at 900 oC for 2 hours to form active CaO catalyst. Then glycerolysis process to produce mono and diacylglyserol. Mono and diacylglycerol that formed was separated by using separator fannel. The upper layer was vaporated to separate MDAG from tert-butanol. The content of MDAG was analyzed using Gas Chromatography. The best result was at 70 oC temperature, ratio co-solvent to oil 3:1 (v/w), 2 hours of reaction time and 4% of catalyst amount from oil and oil molar ratio to glycerol 1:6 with MDAG content of 68,62%. MDAG formed are w/o emulsifier with 5.19 HLB. The result of this research shows that egg shell waste is suitable to be used as source of cheap catalyst to produce mono and diacylglycerol.

Study on Esterifying Conditions of Shrinkage Reducing Monomer

One system of Shrinkage reducing monomer was prepared by esterification reaction, the test method of esterification rate was discussed, to find out the significant factors of the esterification rate by using the orthogonal design. The influence of ether-to-acid mole ratio, reaction temperature, catalyst dosage and reaction time on the esterification was also investigated. The results demonstrate that the suitable esterifying conditions mainly require the suitable proportion of MA to C5H12O3 as 1~1.05 to 1, and under the temperature of 120~125°C, and 3~3.5hours of reaction time.