Green Polyols from Tamanu Seed Oil: Reaction Kinetics and Process Optimization

Thermal degradations of biomass corn leaves were studied for kinetic modeling. Thermogravimetric-differential analyzer runs at 5, 10, 20, and 30 °C min−1 heating rates were employed. Apparent activation energy and frequency factor values were calculated for first-order kinetics using several procedures. The procedure of Coats and Redfern showed 28.89 to 31.78 kJ mol−1 apparent activation energy and 15.5 to 157.12 min−1 frequency factor, respectively. Calculation of the apparent activation energy and frequency factor using Kissinger–Akahira–Sunose procedure gave 229.9–364.2 kJ/mol and 8.567 × 1023 and 1.13 × 1031 (min−1), respectively as the conversion increased from 0.1 to 0.9. The newly introduced excel solver procedure indicates a distribution activation energy over the entire range of conversion. For first-order reaction kinetics, the calculated apparent activation energy magnitudes ranged between 5.0 kJ mol−1 with frequency factor equals to 0.239 and 196.2 kJ mol−1 with frequency factor 2.89 × 1012 in the studied range. The low or high magnitudes of the calculated activation energy are not associated with a particular value of the conversion. The calculated apparent activation energies are related to the direct solution of the simultaneous equations that constitute the basis of the excel solver.

Esterification of acrylic acid (AA) with 1,4‐butanediol (BD) was carried out over a solid acid catalyst to produce 4‐hydroxybutyl acrylate (HBA), an environmentally benign coating agent. The Amberlyst 15 catalyst was more active for the reaction than other ion exchanged resin catalysts such as Amberlyst 35 and DOWEX HCR‐S(E). The quasi‐homogeneous model was chosen to express the esterification reaction kinetics over Amberlyst 15. The stirring speed was changed from 300 rpm to 750 rpm and the reaction rate showed no influence of external mass transfer. The reaction temperature was varied from 100°C to 120°C to calculate activation energies of the reactions. The calculated activation energies were 58.3 kJ/mol and 86.7 kJ/mol for HBA and BDA (1,4‐butanediol diacrylate, by‐product) productions, respectively. The catalyst concentration was also changed from 0.0043 g/ml to 0.0171 g/ml to find its effect on the rate constant. The complete kinetic equation of esterification to produce HBA over the Amberlyst 15 catalyst based on the quasi‐homogeneous model was developed.

A study on palm oil transesterification to evaluate the effect of some parameters in the reaction on the reaction kinetics has been carried out. Transesterification was started by preparing potassium methoxide from potassium hydroxide and methanol and then mixed it with the palm oil. An aliquot was taken at certain time interval during transesterification and poured into test tube filled with distilled water to stop the reaction immediately. The oil phase that separated from the glycerol phase by centrifugation was analyzed by 1H-NMR spectrometer to determine the percentage of methyl ester conversion. Temperature and catalyst concentration were varied in order to determine the reaction rate constants, activation energies, pre-exponential factors, and effective collisions. The results showed that palm oil transesterification in methanol with 0.5 and 1 % w/w KOH/palm oil catalyst concentration appeared to follow pseudo-first order reaction. The rate constants increase with temperature. After 13 min of reaction, More methyl esters were formed using KOH 1 % than using 0.5 % w/w KOH/palm oil catalyst concentration. The activation energy (Ea) and pre-exponential factor (A) for reaction using 1 % w/w KOH was lower than those using 0.5 % w/w KOH. Keywords: palm oil, transesterification, catalyst, first order kinetics, activation energy, pre-exponential factor

Modeling and optimization of trans-esterification of palm kernel oil (PKO) to trimethylolpropone ester (TMP ester- a bio-lubricant) via palm kernel oil methyl ester (PKOME-a biodiesel) synthesis were investigated. The central composite design (CCD) component of the response surface methodology (RSM) was adopted for the optimization of the process parameters, where temperature and weight ratio of PKOME to TMP were held constant at 130 °C and 3.9 : 1 respectively, to generate 20 experimental runs. Bio-lubricant yield was calculated for each experimental run. A quadratic-like model was generated that related the yield to the process parameters (Reaction time, Stirring Speed, and Catalyst concentration). The predicted and actual R2 value were 0.9856 and 0.9959 respectively, which indicate an excellent agreement between experimental and predicted bio-lubricant yield. The predicted maximum bio-lubricant yield was 98.11 % at reaction time of 99.9084 mins, stirring speed of 863.794 rpm, and catalyst concentration 0.84522 wt. %. The experimental value obtained under same conditions was 96.996 %. Physico-chemical analysis of the bio-lubricant synthesized at optimum conditions were found to be within the range of the ASTM standard for bio-lubricants

The kinetics of the Zinc octoate/nonylphenol catalysed thermal cure of bisphenol A dicyanate (BACY) was investigated using non-isothermal differential scanning calorimetry (DSC). The kinetic parameters were estimated by the methods of Coats-Redfern (C-R) and Roger and Kissinger. The overall reaction conformed to first order kinetics. The calculated activation energy (E) and pre-exponential factor (A) depended on the analytical approach. However, the variation in activation energy was associated with a proportional change in A, rendering the overall rate constants nearly identical and independent of the analytical method for a given system. The presence of catalyst enhanced the rate constant. The apparent activation energies, normalised to a fixed A value, were practically identical for a given system, implying the existence of a kinetic compensation effect. The activation energy decreased with increasing catalyst concentration. The variation in activation energy with conversion for a given catalyst concentration was within the kinetic compensation limit for a given system. The activation parameters were used to predict the cure profile of the resin under given conditions of temperature and catalyst concentration.

<p class="AbstractText" style="margin-bottom:3.0pt;"><span style="letter-spacing:-.1pt;" lang="EN-US">The aim of this work was to investigate an advanced oxidation process for removing malachite green from aqueous solutions using a modified Fenton-like process. An experimental Box-Behnken design was applied to determine the optimal conditions by examining the effects of catalyst concentration ([Fe<sup>2+</sup>]), oxidant concentration ([K<sub>2</sub>S<sub>2</sub>O<sub>8</sub>]), and stirring speed. The analysis of variance (ANOVA) indicated that oxidant concentration was the most significant factor, with a p-value of 0.001, while catalyst concentration, the quadratic term of the oxidant, and the interaction between catalyst concentration and stirring speed were also significant. The optimal conditions for maximum dye removal were found to be a catalyst concentration of 3.5 ppm, an oxidant concentration of 3.07 ppm, and a stirring speed of 200 rpm, achieving a theoretical degradation yield of 100% and an experimental yield of 98%. This agreement validates the model and the importance of the optimized parameters. Additionally, degradation kinetics studies in various natural waters revealed that oxidation efficiency followed this order: Distilled water (98%) > Seawater ≈ Industrial water (88.97%) > Source water (85.57%) > Mineral water (80.52%).</span></p>

For successful industrial scale-up and effective cost analysis of transesterification process, presentation of complimentary research data from process optimization using statistical design techniques, chemical kinetics and thermodynamics are essential. Full factorial central composite design (FFCCD) was applied for the statistical optimization of base methanolysis of sea almond (Terminalia catappa) seed oil using response surface methodology (RSM) coupled with desirability function analysis on quadratic model. Reaction time had the most significant impact on the biodiesel yield. Optimum conditions for biodiesel yield of 93.09 wt% validated at 92.58 wt% were 50.03°C, 2.04 wt% catalyst concentration, 58.5 min and 4.66 methanol/oil molar ratio with overall desirability of 1.00. Ascertained fuel properties of the FAME were in compliance with international limits. GC–MS, FTIR and NMR characterizations confirmed unsaturation and good cold-flow qualities of the biodiesel. Based on power rate law, second-order kinetic model out-performed first-order kinetic model. Rate constants of the triglyceride (TG), diglycerides (DG) and monoglycerides (MG) hydrolysis were in the range of 0.00838–0.0409 wt%/min while activation energies were 12.76, 15.83 and 22.43 kcal/mol respectively. TG hydrolysis to DG was the rate determining step. The optimal conditions have minimal error and would serve as a springboard for industrial scale-up of biodiesel production from T. catappa seed oil.

Natural products have been receiving the spotlight from the people of developing and developed countries in recent years due to rising health care expenses and global financial crises. These natural products are the resources for bioactive compounds used in the drug development process. Tamanu seed oil is used for traditional remedies and cosmetic ingredients. The dried seed produces an oil with a yield of 50–75 %. Previous works reported that the seed oil comprised coumarins, one of the eminent groups of phenolics. Coumarins have anticancer, antimicrobial, anti-inflammatory, anticoagulant, antiviral, wound healing properties, and anti-HIV effects. Extraction is often referred to as the sample preparation method as its essential to purify bioactive compounds. In this work, coumarin mixture from tamanu oil was extracted by batchwise multi stages extraction. The effects of solvent used (methanol and ethanol), solvent–water concentration, and the number of stages were studied. The optimal conditions for the extraction of the coumarin mixture were 90 % ethanol and eight stages of extraction, which contributed to 50.73 ± 0.16 % of purity and 92.95 ± 3.76 % of recovery. Also, these conditions removed up to 66 % free fatty acids (FFA) and 100 % triglycerides (TG). It was found that the DPPH inhibition at 400 ppm shows that 90 % ethanol has the highest inhibition (57.72 ± 2.70 %) with an IC50 value of 305 ppm. Moreover, various compounds like pyrrole-2 carboxylate, epicrinamidine, cholestane, and hydroxysclerodin trimethyl ether were also detected in the polar fraction of tamanu oil.

Ochrocarpus longifolius assisted green synthesis of CaTiO3 nanoparticle for biodiesel production and its kinetic study

Chemical kinetics can be a useful tool for determining the optimal operating time of electrochemical processes. The main objective of the study was to determine the mineral oil removal rate by sono-electrochemical treatment. In this study, zero-, first-, and second-order kinetic models were used to determine the reaction rate of mineral oil removal with the sono-electrochemical process. The reaction rate experiments were conducted under the following optimal conditions: 8 min of treatment time, a current density of 53.1 A/m2, and a flow rate of 0.23 L/s. It was found that the changes in mineral oil concentrations follow second-order kinetics with a coefficient of determination of 0.9732. The mineral oil removal efficiency was 94.4%. This study concludes that sono-electrochemical process could be a promising technology for the removal of mineral oil from wastewater, and that the mineral oil removal rate can be determined by chemical kinetics. The results obtained may be useful for the optimization of the sono-EC process and reactor design.

Prediction capabilities of mathematical models in producing a renewable fuel from waste cooking oil for sustainable energy and clean environment

Catalytic esterification, kinetics, and cold flow properties of isobutyl palmitate

The mechanism of paraffin deposition and prevention has been studied in the laboratory using an apparatus which provides a quantitative means of studying paraffin deposition on metal and plastic surfaces. The amount, hardness, adhesion, per cent wax and mean molecular weight of paraffin deposits appear to be governed by surface roughness alone, all other conditions being constant. Tests of various plastic coatings indicate that most smooth, nonparaffinic plastics are capable of reducing paraffin deposits in oil wells, but flexible, highly polar, nonparaffinic plastics are more suitable for providing long term resistance to paraffin deposition in oil wells if the flow stream contains abrasive materials. Introduction The problem of paraffin deposition is one of long standing in the oil industry.' Crude oils often contain paraffins which precipitate and adhere to the liner, tubing, sucker rods and surface equipment as the temperature of the producing stream decreases in the normal course of flowing, gas lifting or pumping. Heavy paraffin deposits are undesirable because they reduce the effective size of the flow conduits and restrict the production rate from the well. Where severe paraffin deposition occurs, removal of the deposits by mechanical, thermal or other means is required, resulting in costly down time and increased operating costs. The troublesome paraffins are normal hydrocarbons ranging from approximately C(18)H(38) to C(38)H(78) mixed with small amounts of branched paraffins, monocyclic paraffins, polycyclic paraffins and aromatics. The amount of paraffins found in crude oils varies from less than 1 to more than 30 per cent. Many publications are available which deal with this problem, and perhaps the most significant findings in recent literature are contained in a publication by Hunt who developed the "cold spot tester", a really useful means of investigating paraffin deposition. Hunt's observations led to many generalized conclusions concerning the effect of surface roughness on paraffin deposits. He ascertained that there was an observable qualitative correlation between the severity of paraffin deposition and the roughness of the surfaces which he tested (cold rolled steel, stainless steel and several plastics). Because of the number of meaningful observations made by Hunt, his cold spot tester was modified somewhat and extensive tests were performed to study the quantitative relationship between surface roughness and the physical and chemical nature of paraffin deposits. LABORATORY TEST PROCEDURES The cold spot test apparatus consists of a flat circular plate mounted on a curved tube and positioned in a vessel containing a wax-oil solution (Fig. 1). The apparatus is arranged so that the temperature of the central portion of the circular plate can be varied by means of a circulating liquid stream; the test equipment includes provisions for maintaining a constant wax-oil solution temperature and stirring speed. In the paraffin deposition studies, the modified cold spot tester was used as follows. The cold spot probe consisted of a flat circular plat 2 in. in diameter and 1/8-in. thick positioned in the wax-oil solution kept at constant temperature. As in Hunt's earlier experiments,' a cold liquid was circulated through a tube connected to the circular plate so that the liquid impinged on one side of the plate cooling the plate from the center outward, causing paraffin to deposit on the side of the plate exposed to the wax-oil solution.

The ever-growing concern for the safety of lives and the environment as well as the depletion in fossil fuels reserves across the globe has led to the keen interests of many researchers in the field of renewable energy. This study was therefore undertaken to investigate the trans-esterification optimization process for biodiesel production from palm kernel using response surface methodology. The materials for the trans-esterification processes were palm kernel oil, Methanol and sodium hydroxide. The effects of reaction temperature (oC), catalyst concentration (wt%) and reaction time (min) on the yield were evaluated. The properties of the biodiesel produced showed that it met the ASTM standard for biodiesel. A quadratic polynomial model, Yield (%) = 78.60–3.12A–.62B + 0.00C -0.75AB – 3.50AC + 1.50BC + 2.82A2– 0.18B2 + 1.08C2, was developed that can be used to predict yield of biodiesel at any value of the different parameters investigated. The ANOVA for the model of the biodiesel yield obtained indicates that the models fit well in describing the relationship between the predictor (biodiesel yield) and the factors (methanol to oil ratio, catalyst concentration and reaction time). The optimal trans-esterification conditions were found to be 60°C for temperature, 60minutes for reaction time, 0.878w% of oil as Sodium hydroxide (catalyst) concentration and methanol/oil ratio of 1:6. At these optimal conditions, the biodiesel yield was fond to be 89.32% The generated biodiesel had high cetane number, better engine ignitability and poses lesser pollution problems than petroleum diesel.

A microwave-based technique to determine saccharides and polyols contents in Spirulina (Arthrospira platensis)