Iranian Journal of Chemistry and Chemical Engineering
Volume:38 Issue: 6, Nov-Dec 2019

This review gives an overview of the applications of ceria nanoparticles as inexpensive, efficient, reusable, and environmentally sustainable heterogeneous catalysts for the synthesis of a variety of key medicinal heterocyclic compounds with the emphasis on mechanistic aspects of the reactions. Literature has been surveyed from 2005 to 2018.

Here, we report the synthesis, characterization, and catalytic evaluation of Ni-Cu-Mg ferrite using tragacanth gum as biotemplate and Metals nitrate as the metal source by the sol-gel method without using any organic chemicals. The sample was characterized by powder X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Vibrating Sample Magnetometer (VSM), and Scanning Electron Microscopy (SEM). The X-Ray powder Diffraction (XRD) analysis revealed the formation of Cubic phase ferriteMNPs with an average particle size of 19 nm. The magnetic analysis revealed that the Ni-Cu-Mg ferrite nanoparticles had a ferromagnetic behavior at room temperature with a saturation magnetization of 27.85 emu/g. The catalytic activity of Ni-Cu-Mg ferrite MNPs was evaluated for the synthesis of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo [5.5.0.05,9.03,11 ] dodecane (HBIW) under ultrasonic irradiation. The catalyst could easily be recycled and reused a few times without a noticeable decrease in catalytic activity.

This study was designed to probe the fabrication of unique silver and gold nano-structures engaging a self-designed chitosan-porous anodic alumina nano-composite as a template. Porous anodic alumina has been manufactured by di-step aluminum anodization in an oxalic acid electrolytic bath. The surface properties of porous anodic alumina were reinforced by chitosan neutralized in sodium hydroxide. Multifarious nano-morphologies of silver, as well as gold nanostructures, were observed. Furthermore, the long chitosan biopolymer chains were degraded by γ-irradiations and the same procedure was employed for modification of porous anodic alumina with γ-degraded chitosan. The morphologies of fabricated silver and gold nanostructures were investigated by scanning electron microscopy, while their composition was evaluated with the help of energy-dispersive X-ray spectroscopy. X-ray diffraction study exposed the face-centered cubic phase for both silver and gold nanostructures. Reflection mode UV-Vis spectroscopy was used to ascertain reflection grooves in the absorption range of silver and gold nanostructures respectively. The technique does not involve any harmful reagent and shows different selectivity than methods in general practice. The achieved results apprised that the fabricated nanostructures offer the advantages of biocompatibility and eco-friendliness for numerous biomedical uses.

The production of zinc sulfate is important both medically and agriculturally. If zinc sulfate is produced without agglomeration at the nanoscale, its absorption in the body is more and faster. In this research, the induction time parameter is assessed for nucleation of zinc sulfate nanoparticles at room temperature and various supersaturations using acetone (as anti-solvent) in the presence of sodium dodecyl sulfate surfactant (SDS). The nucleation mechanism of zinc sulfate nanoparticles altered from primary to secondary by adding SDS surfactant in solution. The morphology of the zinc sulfate nanoparticles was analyzed by a Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) tests. The TEM results revealed that the size of the nanoparticles is between 30 and 35 nm in the presence of SDS surfactant. The experimental data proved that the induction time reduces and improves with increasing supersaturation and SDS concentration, respectively. Meanwhile, the nucleation rate increases with the decrease in the interfacial tension of the zinc sulfate particles. The experimental results were also compared with the predictions of classical nucleation theory and the results proved good agreement between them.

The electrochemical sensor for detecting hydrogen sulfide was fabricated. H2S gas molecules pass through polytetrafluoroethylene membrane with 0.22 mm pore size. Carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) were used to fabricate working and counter electrodes. It can be seen from Field Emission Scanning Electron Microscopy (FESEM) images of the working electrode that MWCNTs-COOH is distributed fairly uniform on the hydrophobic membrane. Quantitative results of Energy Dispersive X-ray (EDX) analysis show the presence of carbon (85.95 wt %) and oxygen (12.95 wt %) on the working electrode. The cyclic voltammetry results show the MWCNTs-COOH responds to H2S. The sensor response up to 56 ppm of H2S gas was measured by chronoamperometry. The sensor showed linear behavior up to 16 ppm. The detection limit of the sensor is 310 ppb and its sensitivity 48 hours after assembling is 0.1436 µA/ ppm. The averages of response and recovery times for 10 ppm of H2S were obtained 6.06 and 4.13 minutes respectively. The sensor with functionalized carbon nanotubes has many advantages than the sensor with raw carbon nanotubes; include more uniformity of fabricated electrodes, greater response, and less noise. Using functionalized carbon nanotubes concerning raw nanotubes increases the response of the sensor by 14.8 times at 10 ppm of H2S. Also, the response of the sensor to 250 ppm concentration of carbon monoxide gas was 4.35 nA which is very low concerning sensor response for hydrogen sulfide (1.64 µA for 10 ppm of H2S).

This paper focuses on intra crystalline diffusion of Ni2+ ions onto NaX and NaY zeolites. The zeolites are obtained by the hydrothermal synthesis method. The samples were characterized by several techniques: X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) and InfraRed Spectroscopy (FT-IR). Physical parameters such as pH solution (2 - 7), adsorbent dose (0.25 - 2 g/L), initial concentration of Ni (II) ions (50 - 200 mg/L) and temperature (298 - 323 K) are optimized. The maximum uptake is 99% and 97% for NaX and NaY zeolite respectively under the optimum conditions: pH ∼ 7 and adsorbent dose of 1 g/L for initial concentration of 50 mg/L at 298 K. The best interpretation of the experimental data is obtained by the Langmuir isotherm with a maximum adsorption capacity of 111.85 and 77.57 mg/g for NaX and NaY respectively. The results show that the kinetic data for both zeolites follow the pseudo-second-order model, indicating the presence of physical adsorption. The free energy (DGo), enthalpy (DHo), and entropy (DS°) are evaluated. The process has proved it's spontaneous and endothermic. Diffusion mechanisms of Ni (II)ions adsorption onto NaX and NaY has shown that intraparticle diffusion is the limiting step of the process. The NaX and NaY have been applied to wastewater from the Algerian industrial zone to eliminate the Ni2+ effluents using the optimal parameters. It has been found that the Ni2+ ions removal yield was 77.81% for NaX and 83.86% for NaY.

Copper vanadate nanoparticles were synthesized by a simple coprecipitation method in an aqueous medium and the products were used as adsorbents for eliminating methylene blue (MB) from water. The structure and morphology of the produced nanoparticles were evaluated through X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) analysis. The results indicated that the particles were 22-40 nm in diameter. Further, batch adsorption experiments were performed to evaluate the potential capability of the product for the removal of MB and optimizing the adsorption conditions. The effects of pH, the quantity of the adsorbent, contact time, dye concentration, and temperature on adsorption were determined. Fitting of the experimental data into the Langmuir and Freundlich adsorption models revealed good compliance with the Langmuir model with a maximum adsorption capacity of 151.5 mg/g at pH= 4.0. Evaluation of the kinetic and thermodynamic parameters showed that the adsorption process follows a pseudo-second-order kinetic model and reaches equilibrium after 10 min. The desorption of the dye and recycling potential of the adsorbent was also studied.

Untreated wastewater disposal containing synthetic dyes produces serious problems in the environment. Industrial wastewater containing dye requires treatment by a suitable process before discharging into the environment. The present study has been performed as a batch experimental study. Nanochitosan was synthesized from the Persian Gulf shrimp shell. The effect of the various parameters including pH, initial concentration of the RB29 dye, the equation contact time, and the adsorbent dosage as well as isotherm, thermodynamic and kinetic of the adsorption process were evaluated. The results of this study demonstrated that the maximum adsorption capacity of the nano chitosan, which occurred in pH=4, adsorbent dosage of 0.2 g/L, the concentration of 50 mg/L of RB29 dye and during 90 minutes, was 113.22 mg/g. Temkin and Dubinin-Radushkeish isotherms and pseudo-second-order kinetic equations have shown better results for describing the adsorption process. The entropic changes (ΔS°) and enthalpy changes (ΔH°) were 36.65J/mole K and 6.43 kJ/mole respectively. Also, the Gibbs free energy (ΔG) was negative. Therefore nano chitosan can be used as a suitable low-cost adsorbent for the removal of RB29 dye from aqueous solutions

In the present work, the solid-state dispersion method has been used to stabilize ZnOon Todorokite (TD). ZnO/TD catalysts have been characterized by SEM and XRD. Optimum process conditions were determined for the removal of Cr(VI) from water using the Taguchi fractional design method. Four controllable factors containing pH, photocatalyst amount, irradiation intensity, and initial concentration of Cr(VI) at three levels were identified for each factor. The optimum conditions were found to be as follows pH= 2, photocatalyst amount= 100 mg/L, irradiation intensity= 7.63 and Cr(VI) concentrations= 15 ppm. In optimum conditions, a first-order reaction to k= 0.1492 min−1 was observed in the photocatalytic reduction of Cr(VI) in water by UV/ZnO/TD.

In this research, selective adsorption of U(VI) in aqueous solutionsin the presence of various lanthanide ions by using U(VI)-imprinted cryogel polymer was conducted. For this purpose, the prepared pHEMA-(MAH)3-U(VI) cryogel polymer by free radical polymerization method. U(VI) was desorbed with 5.0 mol/L HNO3 and thus U(VI)-imprinted were created onto p-HEMA-(MAH)3 cryogel polymer. To determine the optimum conditions, in the process of selective adsorption of U(VI) ion to U(VI)-imprinted p-HEMA-(MAH)3 cryogel polymer, some parameters such as pH, flow rate, initial U(VI) concentration were investigated. Under the optimum conditions, the maximum adsorption capacity was obtained as 74.80 mg/g. Selectivity studies were also carried out in the presence of Nd(III), La(III) and Y(III) ions using U(VI)-imprinted p-HEMA-(MAH)3 cryogel polymer. The obtained adsorption order under competitive conditions was U(VI) ˃ La(III) ˃Y(III) ˃Nd(III).

At the laboratory level, we studied the effects of various factors, the initial concentration of metal ions, the pH of the solution, the amount of mud used and contact time, on the adsorption of zinc, and leads ions onto dam material (Mascara, Algeria). The constituents of silt sediment are quartz, calcite, and a mixture of clays. The equilibrium time was of the order of 60 min. The adsorption diagram is smooth and continuous leading to saturation, suggesting the possible monolayer coverage of zinc and lead ions on the surface of the adsorbent. The extent of adsorption increases with an increase in pH. Furthermore, the adsorption of metals increases with an increasing amount of adsorbent. The adsorption modeling was carried out using the Langmuir and Freundlich adsorption models to determine the mechanistic parameters associated with the adsorption process. The Langmuir–Freundlich isotherm model was the best to describe the experimental data. The maximum sorption capacity was found to be 42.73 and 131.57 mg/g for Zn2+ and Pb2+, respectively.

The coordination compounds of Fe (II) and Fe(III) with phthalic acid were synthesized. The compounds were studied by X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), and IR spectroscopy. It has been established that, regardless of the oxidative number of iron, the synthesis products have the same chemical composition and chemical formula - [Fe2(o-C6H4(COO)2)3]. It also found that the carboxyl groups of phthalate dianion have a monodentate and bridging function and the complex itself is a polymer-layered structure. Based on the obtained results, a schematic structure of the complex was proposed. Also were studied the thermal stability of the complex in the temperature range 20-660 °С and the supramolecular interaction of this substance with the rheological properties of heavy commercial oils. This significantly reduces the viscosity of heavy oil during transportation. Coordination polymer-based composites have been developed and tested. The use of composite solves several technological problems associated with the transport of high-viscosity oil.

A novel polyfunctional dipodal ligand, L = N,N'-bis[2-[(2-hydroxy-1-naphthyl)methyleneamino]ethyl]propanediamide (DOTA2HNAP) was developed and characterized through elemental and spectral analyses. The complexation behavior of the ligand was investigated with Co2+, Cu2+, and Zn2+ metal ions by potentiometric and spectrophotometric methods in the H2O-DMSO mixture (99:1) at µ = 0.1M KCl and 25 ± 1 °C. Four protonation constants for –OH of naphtholate groups and –N of imine were determined for the ligand. The ligand forms monomeric complexes of ML type with the metal ions, where coordination occurs through N-imine and O-naphtholate donors (N2O2). In the case of a complex of copper, an additional species, MLH-2, was formed due to ionization of the amide groups in a higher pH. The minimum energy structures of the metal complexes in solution have been obtained through molecular modeling studies by using the semi-empirical/ PM3 method. The photophysical properties of DOTA2HNAP were investigated in the presence of a wide range of biologically relevant metal ions. The fluorescence emission of the ligand at 450 nm (λex = 361 nm) exhibited a remarkable enhancement with Zn2+ ions (1 equivalent) at physiological pH amongst all metal ions. Such behavior enables the ligand to be considered as a suitable model for the detection of Zn2+ towards environmental applications.

The extraction of Terbium (III)from aqueous nitrate solutions with a supported liquid membrane was investigated using a mixture of di-(2-ethylhexyl phosphoric acid (D2EHPA) and tri-octyl phosphine oxide (TOPO) with a molar ratio 1/0.4. The Hydrophobic Polyvinylidene Fluoride (PVDF) membrane was used as solid support. The sorption process followed pseudo-second-order kinetics. The quantity of 8.29 mg/g was extracted using a Supported Liquid Membrane (SLM). The influence of the ionic strength, stirring rate, extraction time, and the interactions between them on the extraction yield of Terbium (III) ions was investigated using the factorial designs. The analysis of variance was used to show the relative importance of the extraction process parameters.

In this study, moisture content, free fatty acids, peroxide, iodine value, unsaponifiable matter, saponification value, fatty acid composition and tocopherol contents of wheat germ oil obtained by SC-CO2 extraction and cold press technology were investigated. Moisture, free fatty acid (FFA), peroxide value, iodine value, unsaponifiable matter and saponification value of cold press and supercritical CO2 extraction method oils were established as 0.097% and 13.32, 0.84% and 5.9%, 8.9 meq O2/kg and 15.8, 132 and 128, 6.5 g/kg and 8.04 and 197 and 182mg KOH/g, respectively. Major fatty acids of samples were determined as palmitic, oleic, and linoleic acids. Campesterol and β-stosterols of wheat germ oils obtained by the cold press and supercritical CO2 extraction are the major sterols. The germ oil extracted by both methods contained 24.19% and 23.44 % campesterol and 60.98% and 61.56% β-stosterol, respectively. While germ oil obtained supercritical CO2 extraction contains 50.60% α-tocopherol and 49.39% β-tocopherol, the oil obtained by cold press contained 73.12% α-tocopherol and 26.83% β-tocopherol. Supercritical CO2 extraction is conducted for the process that must be decided whether the pilot or industrial scale. Supercritical CO2 extraction that high oil yield is very high investment costs.

Theoretical assessment of the protonation reaction in the activation of propene on hydroxylated Mo(VI) and W(VI) metathesis catalysts is presented in this paper using the density functional theory calculations and five support clusters varying from simple SiO4H3 clusters to a large Si4O13H9 cluster. The bond distances and thermochemical data were similar for most of the clusters. The formation of isopropoxide was more favorable than a propoxide counterpart bonded via the primary carbon atom, with the Gibbs free energies of –3.73 and –7.78 kcal/mol, respectively, for the W catalyst. Overall, the 1T cluster models with optimized H atoms or an all-relaxed alternative would be considered appropriate replacements for a larger 4T cluster model saturated with OH groups and optimized terminal hydrogen atoms. The largest deviations in the energetic data were observed between the protonated structures formed on the two larger clusters saturated with either OH or H groups.

Single and mixed oxide Al/Zr-pillared clay (Al/Zr-PILC) catalysts were synthesized and tested for catalytic wet air oxidation (CWAO) of aqueous phenol solution under milder conditions, in a semi-batch reactor. The catalysts were synthesized from natural bentonite clay using ultrasonic treatment during the aging and intercalation steps and were characterized using High Resolution Scanning Electron Microscopy-Energy Dispersive angle X-ray spectrometry (HRSEM-EDX), powder X-ray diffraction (p-XRD), nitrogen adsorption/desorption, Fourier Transforms InfraRed Spectroscopy (FTIR) and zeta potential. Successful pillaring of aluminum and zirconium oxides into the clay was confirmed by p-XRD with increased basal spacing (1.92 nm) and higher specific surface area (230 m2/g). The influence of stirrer speed (200-1000 rpm), catalyst dosage (1-3 g/L), initial pH (1-3), initial phenol concentration (500-1500 mg/L), the effect of temperature (80-150 °C) and oxygen pressure (5-15 bar) was evaluated on phenol conversion and their reaction kinetics. At the optimum conditions of initial pH of 3, catalyst dosage of 2 g/L, initial phenol concentration of 1000 mg/L, reaction temperature of 100 °C, and oxygen pressure of 10 bar, the complete removal of phenol was achieved by Al/Zr-PILC within 120 min. The CWAO process was well-described by the first-order power rate law kinetics model. The apparent activation energy of the reaction calculated by Arrhenius equation was 21.306 kJ/mol.

Ketenimines and azadienes are transient intermediates in organic chemistry especially in elimination-addition processes and in the formation of heterocyclic systems. These compounds play a considerable role as intermediates in the synthesis of heterocyclic ring systems. In this present research synthesis of novel ketenimines and azadienes via multicomponent reactions (MCRs) based on alkyl-Isocyanides is reported. Following our ongoing interest in isocyanide-based MCRs, we reported stereoselective reactions between 4H-3,1-benzoxazine-2,4(1H)-dione (isatoic anhydride) with dialkylacetylenedicarboxylates in the presence of alkyl isocyanides under solvent-free microwave conditions which leads to novel functionalized ketenimines and azadienes in a green route. The results show that the microwave-assisted leaching process has advantages over the conventional ones, concerning energy-consumption, processing time, and environmental protection.

In search of potent cholinesterase inhibitors, we have carried out the synthesis and biologically evaluation of various benzaldehyde based 2,3-dihydroquinazolin-4(1H)-one derivatives. In vitro assay results revealed that all the synthesized compounds showed activity against both enzymes (AChE and BChE) and in few cases, the inhibition activity was even higher than or comparable to the standard drug galantamine. Overall, compounds having chloro or methoxy group attached to the para position of benzaldehyde resulted in potent cholinesterase inhibitors. Within the series, Bromo derivatives 4a-i were more active than their un-substituted counterparts. Amongst all, compound 4c (6,8-dibromo-2-(3-bromo-4-chloro-phenyl)-2,3-dihydro-1H-quinazolin-4-one) with selectivity index of 3.7 for AChE, displayed IC50 values of 3.7±1.05 µM (AChE) and 13.7±0.64 µM (BChE) and can be considered as potential lead compound with a feature of dual cholinesterase (AChE/BChE) inhibition. Insight into the mechanism of inhibition of the synthesized compounds was provided by computed binding modes in the active site of AChE and BChE.  Docking study on both isomers of the quinazoline also supported in vitro assay results. Preliminary in silico studies by using online admetSAR server showed that all compounds possessed good pharmacokinetic profile except nitro and methoxy substituted derivatives which were predicted to exhibit AMES toxicity. The synthesized compounds can be used as a structural foundation for the preparation of new potent cholinesterase inhibitors.

In this manuscript, we describe the synthesis of the carbohydrazide 2. Acid-catalyzed condensation with several carbonyl compounds to afford the corresponding carbohydrazide derivatives 3-12. Their acetylation afforded the corresponding acetyl derivatives 13-22. Oxidative cyclization of O-acetyl derivatives 19-22 afforded the corresponding 1,3,4-oxadiazole derivatives 23-26. On the other hand, condensation of the dicarbonyl compound 27 with several aroylhydrazines to give the corresponding bisaroylhydrazones 28-32 cyclization of 28-31 afforded 1,3,4-oxadiazoles 33-36. The structures of the prepared compounds were confirmed by 1HNMR and Mass Spectra. The mechanism of the formation of the products was discussed. Furthermore, the antioxidant activities of some of the prepared compounds were examined.

Rising cases of antibiotic-resistant bacteria is a public health concern. Many approved antibiotics target penicillin-binding proteins example peptidoglycan transpeptidase (PTPase). Due to wide pharmacological activity of phenothiazines, new styryl, aryl, alkynyl, and thiophenyl benzo[a]phenothiazines were synthesized and their inhibitory potency against PTPasein silico and Gram-positive/Gram-negative bacteria evaluated. The compounds inhibited the activity of PTPase at 18.93 - 75.48 µM and their best-docked poses identified interaction with PTPase Tyr318, His336, and His352. Experimental results agreed with computational predictions and further confirmed the benzo[a]phenothiazines as potential antibiotics. Also, the identified essential residues could be targeted during the rational optimization of the analogs.

A new manganese(II) complex containing p-hydroxybenzoate and caffeine ligands, namely [Mn(OH-C6H4COO)2(H2O)4].2(C8H10N4O2).8H2O has been prepared. The synthesized complex has been characterized by elemental analyses, FT-IR spectroscopy, X-ray crystallography, and molar conductance measurements. The thermal properties of the complex were analyzed by TGA/DTA. The complex crystallizes in the monoclinic space group P21/c having cell dimensions a=11.1311(2), b=14.3579(3), c=13.5383(3) Å, β=101.879(2)º, V=2117.34(8) Å3, Z=2. In the mononuclear complex, Mn atom is coordinated by two p-hydroxybenzoate anions and four water molecules. Moreover, the asymmetric unit of the complex also contains four uncoordinated water molecules and one caffeine ligand. Crystal structure of the complex has 3D supramolecular networks formed via O-HOH···Ocaf, O-Hw···Ow, O-Hw···Ncaf, O-Hw···Ocaf, and O-Hw···Ocar hydrogen bonds.

The main challenge in Wastewater Treatment Plants (WWTP) by activated sludge process is the reduction of the energy consumption that varies according to the pollutant load of influent. However, this energy is fundamentally used for aerators in a biological process. The modeling of energy consumption according to the decision parameters deemed necessary for good control of the active sludge process namely the removal yields of parameters pollutant such as Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Suspended solids (SS) and Ammoniac (NH4+) that must meet the required standards. To achieve this objective, a coupling of two approaches, the principal components analysis (PCA) method and the Adaptatif Neural  Fuzzy Inference System (ANFIS) model was envisaged, to improve the performance of fuzzy reasoning. Indeed, PCA as a factorization tool allowing the reducing of the variable that allows the reduction of the complexity of the studied phenomenon. The neuro-fuzzy learning from the data projected on the principal axes allows the improvement of the model, both in learning and validation periods. The comparative study between ANFIS model, the regression PCA model, and the coupling PCA-ANFIS method applied to the raw data was effected. The results indicate a significant improvement in the validation criteria obtained in the coupling PCA-ANFIS model compared to the other models for the learning and validation periods. The result shows that the coupling PCA-ANFIS can be used to extract information from data and to describe the nonlinearity of complex wastewater treatment processes.

Bacillus mojavensis PTCC 1696 (a member of Bacillus subtilis group) has been isolated from the Iranian oil field (Masjed-I Soleyman), to examine its ability to produce biosurfactant (lipopeptide type) [28]. The present study was designed to characterize the antibacterial activity of the isolated biosurfactant. The antibacterial activity towards several bacteria including clinical isolates and type strains species was examined. For detecting the extent of antibacterial activity, the agar disc diffusion method was used, where the measured diameter of the zone of inhibition was used as an index for determining the antibacterial activity. Among the test microorganisms, the antibacterial activity was highest in Pseudomonas aeruginosa ATCC 27853. At concentration as low as 16 μg/ml, the inhibitory effect of the lipopeptide biosurfactant was detectable. The stability of the test biosurfactant also was examined over a wide range of temperatures (40–100°C)and pH values (2-11). The stability was further tested using protease and lipase, where the substance showed clear sensitivity towards lipase. The potentiality of this antibacterial agent in clinical applications is of interest and needs to be further recognized.

The purpose of this paper is to find the optimal geometry of Venturi for the production of biodiesel by hydrodynamic cavitation. Intensive methods such as hydrodynamic cavitation eliminate the limitation of mass transfer in the transesterification reaction. In this paper, a venturi design was developed to create cavitation in biodiesel production. The most important property of venturi in creating cavitation and retrieving the pressure is the convergence and divergence angles. The four convergence angles of 22°, 20°, 17°, and 15° and four divergence angles of 12°, 10°, 7° and 5° in Gambit 2.4 software were designed and evaluated with Fluent 6.3 software and their CFD was analyzed. The maximum pressure recovery (85% of input pressure) and cavitation generation was for venturi 17-10 (Convergence angle 17° and divergence angle 10°), which was used in the experimental setup of biodiesel production. The biodiesel production efficiency with this venturi was 95.6%. The FTIR spectrum of the biodiesel was taken to confirm its purity.

The objective of this article was to study the effect of pyrolysis temperature and mineral matter on the distribution of the products of C1-C6 hydrocarbons. Pakistani lignite named Lakhra 6B was used to study the effect of inorganic substances on the reactivity of coal. The experiments were performed using pyrolysis gas chromatography to investigate the activity of virgin coal, HCl acid-washed coal, and acid-washed coal with (Ca(C2H3O2)2, Mg(C2H3O2)2, NaC2H3O2, KC2H3O2), added respectively. The products obtained were monitored by a gas chromatograph. The main products identified were methane, ethane, ethylene, propane, 1-butene, n-butane, 1-pentene, n-pentane, and benzene. The results showed that coal conversion to methane increased with an increase in temperature and the amount of this hydrocarbon was high among all the hydrocarbons formed. It was observed that the addition of metal ions affected the yields of the products selectively. The yield of benzene was observed to be high in the case of calcium and magnesium form coals. The other cations form coals produced a smaller quantity of benzene in the temperature range studied. From the results, it can be concluded that metal ions played a selective role in controlling the yield of C1-C6 hydrocarbons products from coal pyrolysis in general and benzene yield in particular.