Catalyst Molar Ratio Research Articles

Catalytic performance of hexagonal boron Nitride@ APTS-SO3H as heterogeneous nanocatalyst for biodiesel production

In this study, the synthesis of a new stable hexagonal boron nitride (h-BN) is reported via the combustion of boric acid and urea using a pyrolysis method. The surface of hBN particles was modified and the physical/chemical properties of h-BN-APTS-SO3H were examined by different characterization, confirming the modification of h-BN. The effects of methanol/acid molar ratio, temperature, and amount of catalyst were investigated. The results showed that the optimal conditions for the esterification of palmitic acid were as follows: methanol to a palmitic acid molar ratio of 30:1, a temperature of 50 °C, a catalyst of 300 mg for 5 h, and a maximum yield of biodiesel of 90 % was achieved. Furthermore, the quality parameters of the biodiesel were made according to ASTM methods [ASTM D445: Kinematic viscosity, ASTM D445: Flash-point, ASTM D92: Ash content, ASTM D6751: Density]. Tests indicate that the quality parameters of the prepared biodiesel were within ASTM standards. Significantly, the h-BN@APTS-SO3H(1) catalyst showed excellent stability on repeated reuse and can be recycled several times without much activity loss.

ZnO/fly ash catalyst for producing biodiesel from kapok seed (Ceiba pentranda) oil

The quantity of fossil fuels has decreased every year due to increasing energy consumption, thereby requiring alternative renewable energy sources such as biodiesel from kapok seeds. Basically, making biodiesel needs a catalyst. Catalysts are classified into two types based on their phase: homogeneous and heterogeneous. This research employed a ZnO heterogeneous catalyst with fly ash support. It investigated the optimal mole ratio of catalyst and kapok seed oil as well as the optimal catalyst dose to produce the best biodiesel yield. The methodology in this study consisted of ZnO preparation, fly ash preparation, ZnO/fly ash catalyst synthesis, and biodiesel production by the transesterification reaction process. The research variables included the dose of catalyst (wt% oil) of 3, 4, 5, 6, and 7 and the mole ratios of oil to methanol of 1:9, 1:12, 1:15, 1:18, and 1:21. The results of this study indicated that the best catalyst dose was 5% with a biodiesel yield of 58%. Meanwhile, the variable molar ratio of oil to methanol got the highest yield of 65% at 1:8. Therefore, a zinc oxide catalyst with fly ash as support had great potential to produce biodiesel from kapok seed oil.Keywords: Biodiesel; Kapok Seed Oil; ZnO; Fly ash; Yield

Aqueous-phase hydrogenolysis of glycerol over NiCeZr catalysts using in-situ produced H2: Effect of Ce/Zr ratio

Glycerol is a renewable carbon resource for producing high-value products via hydrogenolysis. Herein, we investigated the impact of Ce/Zr molar ratios of NiCeZr-x catalysts, synthesized using a single-step co-precipitation method, on their physico-chemical and catalytic properties during the hydrogenolysis of glycerol with in-situ generated H2. The catalytic performance of the NiCeZr-x catalysts depended significantly on the synergy between oxygen vacancies, acid-base properties, and metallic sites. Ce-rich catalysts increased hydrogen production, whereas Zr-rich catalysts showed higher selectivity in breaking C–O bonds, leading to significant 1,2-propylene glycol yields. The catalyst with a Ce/Zr molar ratio of 15/85 displayed superior performance, attaining a 75.3% glycerol conversion, 29.7% yield, and 52.8% selectivity for 1,2-propylene glycol at 235°C/35 bar and 12 h−1. After use, the Ce-rich catalysts underwent oxidation and coalescence of nickel, whereas the Zr-rich catalysts exhibited Ni leaching. The results indicated that Zr-rich NiCeZr-x catalysts possessed potential to sustainably produce deoxygenated products from glycerol, making it an eco-friendly alternative.

Glucose conversion process to methyl lactate catalyzed by SnCl4-based homogeneous catalysis

Biomass is a renewable alternative to fossil fuels and a valuable source of chemicals. In this study, a facile and efficient method was established to improve the selectivity of methyl lactate (MLA) for the homogeneous Lewis acid catalyzed chemical conversion of glucose and methanol. The effects of catalyst dosage, reaction temperature, and reaction time were systematically investigated, with an emphasis on the variation trends of MLA and other by-products. Through process optimization, the best catalyst molar ratio was 0.075 to 0.1, the reaction temperature was 170 to 180 °C, and the reaction time was 3 h. Under these conditions, the conversion of glucose in methanol exceeded 98%, and the yield of MLA was greater than 40%.

Diastereoselective synthesis of cis‐1,2‐limonene oxide using dimeric Salen‐Mn (III) complexes as reusable catalysts

Diastereoselective epoxidation of R‐(+)‐limonene using achiral and racemic dimeric Salen‐Mn (III) complexes as catalysts ((1a) and (1b)) and in situ generated dimethyldioxirane (DMDO) as an oxidizing agent was explored. The best reaction parameters were: (i) KHSO5/R‐(+)‐limonene molar ratio = 0.25; (ii) R‐(+)‐limonene, catalyst molar ratio = 20, (iii) absence of nitrogenous bases (axial ligands), (iv) ambient temperature (20°C), (v) racemic dimeric catalyst, and (vi) low amount of acetone (4 mL). Under these reaction conditions isolated yield to 1,2‐(+)‐limonene oxide and diastereomeric excess (d.e), and diastereomeric yield excess (d.y.e) to major diastereomer (cis‐epoxide) was 96%, 77%, and 72%, respectively. Moreover, the catalyst was segregated into a solid phase, while products remained in the liquid phase, allowing the easy separation of the catalyst and reaction products. Consequently, the catalyst could be recycled up to three times without appreciable loss of its initial catalytic activity.

Polymerization of N‐Butyl Vinyl Ether Catalyzed by Iron‐Containing Imidazolium‐Based Ionic Liquid

AbstractThe iron‐containing imidazolium‐based ionic liquids (ILs) 1‐n‐butyl‐3‐methylimidazolium heptachlorodiferrate (BMI.Fe2Cl7) and 1‐n‐butyl‐3‐methylimidazolium tetrachloroferrate (BMI.FeCl4) are applied as catalysts in the homogeneous polymerization of n‐butyl vinyl ether. Both solventless conditions as well as using different organic solvents, catalyst concentrations, temperatures, and reaction times are tested to assess the polymerization conditions that lead to the highest molecular weights of poly(n‐butyl vinyl ether). The Lewis acidic IL BMI.Fe2Cl7 proves to be highly efficient, even at low catalyst concentrations. In bulk polymerization, polymers with 142 kg mol−1 are obtained using a 1:10000 molar ratio of catalyst to monomer. In solution polymerization, the monomer consumption is also rapid and the molecular weight of the polymer is related to the catalyst concentration used. These results indicate the potential of this catalyst for industrial applications. In contrast with the acidic IL, the neutral iron‐containing imidazolium‐based IL BMI.FeCl4 does not show any catalytic activity.

Selective synthesis of oleyl alcohol via catalytic and non‐catalytic liquid‐phase methyl oleate reduction

AbstractThe upgrading of oleyl alcohol synthesis via methyl oleate reduction using NaBH4 without H2 supply was investigated. It was possible to synthesize selectively oleyl alcohol with high yields. Non‐catalytic and catalytic experiments were developed trying to improve the low final oleyl alcohol yield previously obtained. The effect of reaction temperature, methyl oleate/NaBH4 molar ratio and properties of different catalysts on final oleyl alcohol yield were analyzed. Thus, alumina‐supported metal (M) catalysts (M = Fe, Ce, Mo) were synthesized by incipient wetness impregnation. The M/Al2O3 catalysts were characterized in their chemical, textural, structural and acid–base properties using ICP, N2 physisorption, XRD and temperature‐programmed desorption (TPD) of NH3 and CO2. During non‐catalytic methyl oleate reduction, final methyl oleate conversion and oleyl alcohol yield of 94% were obtained using a methyl oleate/NaBH4 molar ratio of 0.11 at 333 K. Catalytic activity of M/Al2O3 solids increases as acid site number and ionic potential of M cations increase. In addition, the reaction mechanism for fatty acid methyl ester reduction was investigated from a theoretical approach using Density Functional Theory method at B3LYP/6‐31++G(d,p) computational level. Results obtained during theoretical calculations confirmed that the formation of reducing alcoxyborohydride species is energetically favored and allowed to understand the events at microscopic level involved in the reaction mechanism.

Ring opening polymerisation of ɛ-caprolactone with novel microwave magnetic heating and cyto-compatible catalyst.

We report on the ring-opening polymerization of ɛ-caprolactone incorporated with a magnetic susceptible catalyst, FeCl3, via the use of microwave magnetic heating (HH) which primarily heats the bulk with a magnetic field (H-field) from an electromagnetic field (EMF). Such a process was compared to more commonly used heating methods, such as conventional heating (CH), i.e., oil bath, and microwave electric heating (EH), which is also referred to as microwave heating that primarily heats the bulk with an electric field (E-field). We identified that the catalyst is susceptible to both the E-field and H-field heating, and promoted the heating of the bulk. Which, we noticed such promotion was a lot more significant in the HH heating experiment. Further investigating the impact of such observed effects in the ROP of ɛ-caprolactone, we found that the HH experiments showed a more significant improvement in both the product Mwt and yield as the input power increased. However, when the catalyst concentration was reduced from 400:1 to 1600:1 (Monomer:Catalyst molar ratio), the observed differentiation in the Mwt and yield between the EH and the HH heating methods diminished, which we hypothesized to be due to the limited species available that were susceptible to microwave magnetic heating. But comparable product results between the HH and EH heating methods suggest that the HH heating method along with a magnetic susceptible catalyst could be an alternative solution to overcome the penetration depth problem associated with the EH heating methods. The cytotoxicity of the produced polymer was investigated to identify its potential application as biomaterials.

Testing of Some Ionic Liquids at the Synthesis of Biodiesel

The aim of the present work was to the preparation of biodiesel from sunflower oil and methanol by the transesterification reaction in the presence of some ionic liquid catalysts. The yield was 98% using a 1:5 molar ratio of oil-based ionic liquid catalyst. Important fuel exploitation properties of B20 and B50 fuel blends have been investigated. The obtained results showed that B20 and B50 blends have a greater advantage for diesel engines than B100 and fossil diesel fuels. The best results were demonstrated B20 fuel blend among the studied fuels.

Fast pyrolysis of bagasse catalyzed by mixed alkaline-earth metal oxides for the selective production of 4-vinylphenol

4-Vinylphenol (4-VP) is a value-added phenol compound, which can be obtained from the pyrolysis of herbaceous biomass, and its yield can be further improved through the in-situ catalytic fast pyrolysis process. Herein, a barium-magnesium mixed metal oxide (BaMg-MMO) catalyst was developed and employed for the selective production of 4-VP from bagasse fast pyrolysis. The effects of Ba/Mg molar ratio in the BaMg-MMO catalyst, pyrolytic temperature, catalyst-to-bagasse (CA-to-BA) ratio were carefully investigated based on pyrolysis-chromatography/mass spectrometry (Py-GC/MS) tests. The 4-VP yield reached a maximal of 7.3 wt% with the corresponding selectivity of 44.4% at 300 °C under the Ba/Mg molar ratio of 1:1 and the CA-to-BA ratio of 4:1, compared with that of 5.0 wt% in the non-catalytic process. Moreover, a series of lab-scale fast pyrolysis tests of bagasse were carried out in a fixed bed reactor using BaMg-MMO with a Ba/Mg molar ratio of 1:1. The highest 4-VP yield and selectivity were 7.1 wt% and 56.6% at 300 °C with the CA-to-BA ratio of 1:1. The results indicated that BaMg-MMO could provide a promising catalytic performance on the formation of 4-VP during the fast pyrolysis of bagasse.

Optimization of Parameters Using Taguchi Orthogonal Array Design for an Intensified Per-Pass Conversion of Alphabutol® Technology in Butene-1 Production

Taguchi orthogonal design was used in this study to investigate the effects of three operational parameters (i.e., reactor temperature, reactor pressure, and catalyst ratio on per-pass conversion (PPC)). The optimal PPC was calculated from the predicted response function at 48°C of reactor temperature, 21 kg/cm2g of reactor pressure, and catalyst mole ratio of 2.50. Under these conditions, the PPC was estimated to be 87.1 per cent, with a maximum SNR of 38.95. In line with the delta ranking, the decreasing order of significance of each process parameter on the average per-pass conversion (PPC) was x1 > x2 > x3, with percentage contributions of 50.6%, 26.1%, and 23.3% for reactor temperature, temperature, and catalyst mole ratio, respectively. The optimal production condition can therefore be attained at a larger scale with the higher per-pass conversion of butene-1.

Studies on Xanthium strumarium L. seed oil: Biodiesel Synthesis and Process Optimization

The existing conventional energy sources are depleting day by day, their prices are increasing, so there is necessity to make use of sources of alternative energy. Biodiesel stands as an important alternative to diesel. It is obtained from human consumable and non-consumable oil. In this paper study of biodiesel synthesis and process optimization for kinematic viscosity and biodiesel yield obtained from Xanthium strumarium L. seed oil is carried out through Taguchi L9 (34) orthogonal array by considering methanol: oil mass molar ratio, heating temperature, heating time and concentration of catalyst as variable parameters. Stirring speed is taken as constant parameter. For optimization concentration of catalyst 0.8% to 1.2% by weight, methanol: oil molar proportion from 5:1 to 7:1, reaction temperature from 550C to 65 °C and heating duration of 40 to 50 min is used. By using ANOVA contribution of each factor on biodiesel yield and kinematic viscosity is determined. The result shows that, biodiesel produced from Xanthium strumarium L. seed oil has properties similar to other biodiesel fuel and are as per ASTM standards.

Effect of molar ratios of phenol, formaldehyde, and catalyst on the properties of phenol–formaldehyde resin with partial replacement of synthetic phenol with depolymerized lignocellulose biomass

Effect of molar ratios of phenol, formaldehyde, and catalyst on the properties of phenol–formaldehyde resin with partial replacement of synthetic phenol with depolymerized lignocellulose biomass

Facial synthesis of V-containing CuMgAl-LDHs as a new catalyst for the phenol hydroxylation

• Vanadate-intercalated LDHs was prepared by ultrasonic-assisted co-precipitation method. • One step hydroxylation of phenol to catechol and hydroquinone was carried out using H 2 O 2 as oxidant and H 2 O as solvent. • Excellent conversion of 50.22% and a yield of 28.75% was obtained for vanadate-intercalated LDHs. One step liquid phase hydroxylation of phenol to catechol and hydroquinone over vanadate-intercalated Cu/Mg/Al-layered double hydroxides (LDHs) was carried out using hydrogen peroxide as an oxidant and water as a solvent. The catalyst was synthesized by ultrasonic-assisted co-precipitation and ion-exchanged method under N 2 atmosphere. Also, the catalyst was characterized by IR, XRD, TG-DTA, ICP, BET, FE-SEM, TEM, and elemental mapping analyses. The result indicated the LDHs lamellar structure and plate-like shape particles of the synthesis catalyst with good vanadate intercalation. The effect of several reaction parameters, such as the amount of catalyst, phenol: oxidant ratio, reaction temperature, and time, were studied. After modifying the reaction condition, the CuMgAl-(V) catalyst exhibited an excellent conversion of 50.22% and a yield of 28.75% with the best selectivity of 57.26% at 80 °C, 6 h, phenol: oxidant ratio = 1:1, and phenol/ catalyst molar ratio = 125.

Preparation of a novel ionic liquid and its application in the synthesis of trimethylolpropane trioleate

The 1-(3-sulfopropyl)-3-vinylimidazole inner salt was prepared through the reaction of 1-vinylimidazole and 1,3-propanesultone, and then, it was mixed with different acids to synthesize three kinds of vinylimidazole acidic ionic liquids. The three ionic liquids (ILs) were used as catalysts for the catalytic synthesis of trimethylolpropane trioleate, and the effects of the catalyst amount, reaction time, reaction temperature, and molar ratio of reactants on the catalytic activity were studied. The esterification rates obtained using the three ILs as catalysts could reach 95.82%, 95.37%, and 97.88%. The catalytic kinetics of the synthesized ionic-liquid catalyst was studied, and the activation energies of the forward and reverse reactions were 13.9872 kJ mol−1 and 13.9918 kJ mol−1, and the pre-exponential factors were 2.781 × 10–2 L mol−1 h−1 and 4.835 × 10–5 L mol−1 h−1, respectively. The vinylimidazole acidic ILs showed good catalytic activity in the esterification reaction; thus, the catalysts are suitable for esterification reaction systems and valuable for research. Moreover, the existence of double bonds paves a way for the subsequent research on polymerized ionic liquids.

Facile adjusting the concentration of siliceous seed to obtain different HZSM-5 zeolite catalysts for effective catalytic depolymerization reaction of lignin

To improve lignin depolymerization reaction performance of HZSM-5 zeolite catalyst, we reported the effective catalytic depolymerization of rice husk lignin (RHL) to lignin phenolic monomer (LP) products over the different Si/Al mole ratios of HZSM-5 zeolite catalyst. Firstly, five samples comprising different Si/Al mole ratio of HZSM-5 zeolite catalyst were prepared by the physical method. The X-ray powder diffraction (XRD), scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), pyridine adsorption Fourier transform infrared spectroscopy (FT-IR), and temperature-programmed desorption of ammonia (NH3-TPD) were used to characterize various catalysts. Secondly, gas chromatography–mass spectrometry (GC-MS), 2D heteronuclear single quantum coherence (2D-HSQC), and gel permeation chromatography (GPC) were used to characterize various catalytic depolymerization products. The effect of different Si/Al molar ratios on the lignin conversion to LP products and the structural changes of residual lignin were analyzed. Finally, according to the results of LP products, we discovered that after the use of different Si/Al molar ratios of HZSM-5 zeolite catalysts, the content of acid in the different catalysts which increased with decreasing the Si/Al mole ratios. Among them, the A4P PM products (A4P: having a saturated or unsaturated aliphatic side chain in C4 position) increased from 0.58% (SA560, Si/Al: 560) to 1.83% (SA70, Si/Al: 70), the C6P PM products (C6P: having no side chain in C4 position of G, S, and H structure) increased from 1.53% (SA560, Si/Al: 560) to 3.41% (SA70, Si/Al: 70). Finally, the highest 6.05% PM products yield appeared in the SA70 (Si/Al: 70) catalytic system. It is worth noting that PM products produced by this HZSM-5 zeolite catalyst SA70 have great potential to be a promising renewable alternative to fossil resources.

Highly efficient Co(II) porphyrin catalysts for the extractive oxidative desulfurization of dibenzothiophene in fuel oils under mild conditions

Co(II) porphyrins have been utilized as efficient and selective catalysts for the extractive oxidative desulfurization reaction on the refractory dibenzothiophene (DBT) in [Formula: see text]-dodecane (model middle distillate fuel oil). The acetonitrile was taken as extracting polar solvent and H2O2 was used as oxidant. The reaction optimization was done with respect to DBT:catalyst molar ratio; DBT:H2O2 molar ratio; extracting solvent: CH3CN/[Formula: see text]-dodecane volume ratio; reaction temperature and time. Under the optimized conditions, a maximum of [Formula: see text]98% DBT removal was achieved by using the meso-tetrakis(4[Formula: see text] methoxyphenyl)porphyrinatocobalt(II) as catalyst under mild conditions at 50[Formula: see text]C.

Intensification and optimization of biodiesel production using microwave-assisted acid-organo catalyzed transesterification process

To produce biodiesel cost-effective, low-cost, high free fatty acid (FFA) oil feedstock is desirable. But high FFA creates difficulty during the base-catalyzed transesterification process by yield loss due to the formation of soap. However, these problems are overcome by the use of an acid catalyst. The acid catalysts can directly convert both triglycerides and FFAs into biodiesel without the formation of soaps or emulsions. The shortcomings of mostly used inorganic acids are that they work well for esterification of FFA present in low-cost oil, but their kinetics for transesterification of triglycerides present in oils is considerably slower. Corrosion of equipment is another major problem associated with an inorganic acid catalyst. The usage of an organic acid catalyst of the alkyl benzene sulfonic type, like 4-dodecyl benzene sulfonic acid (DBSA) minimizes these disadvantages of inorganic acid-catalyzed transesterification. The aim of the present investigation was to reduce the reaction time of transesterification of triglycerides further by using microwaves as a heating source in the presence of DBSA catalyst to achieve higher conversions under mild operating conditions. To optimize the transesterification variables for the higher conversion of biodiesel, the response surface methodology was employed to design the experiment. By using the DBSA catalyst under microwave heating at a temperature of 76 °C, conversion close to 100% in only 30 min of reaction time was obtained using a 0.09 molar ratio of catalyst to oil and 9.0 molar ratio of methanol to oil. A modified polynomial model was developed and was adequately fitted with the experimental data and could be used for understanding the effect of various process parameters. The catalyst to oil molar ratio and reaction temperature created a stronger effect on the biodiesel production than that exhibited by the methanol to oil molar ratio. It was observed that the microwave heating process outperformed conventional heating, providing a rapid, easy method for biodiesel synthesis from triglycerides in the presence of DBSA, an organic acid catalyst. The produced biodiesel was of good quality, as all the properties were within the prescribed limits of the ASTM D6751 standard.

Synthesis Of Glycerol Carbonate From Glycerol And Urea Using Limestone As Catalyst Source

Synthesis of Glycerol carbonate from glycerol and urea using limestone as a catalyst has been conducted. This study aims to make glycerol carbonate from glycerol and urea by utilizing scattered natural limestone widespread in Southeast Sulawesi as a catalyst source. The catalyst was obtained from the calcination of natural limestone to decompose CaCO3 to CaO. This condition added to glycerol and urea to test the catalyst activity. Synthesis of glycerol carbonate was carried out through the carbamoylation reaction of glycerol with urea. The advantage of this method is the reaction carried out with free solvents and running in ambient pressure (1 atm). The stages of catalyst testing in the reaction of glycerol carbonate formation were carried out by reacting glycerol, urea, and calcined limestone with 1: 1 substrate mole ratio with a catalyst concentration of 5% mass over glycerol. Characterization used was Fourier Transform Infrared Spectroscopy (FTIR) and supported by Gas Chromatography (GC) data. Optimization catalysis reaction was obtained at a temperature of 140oC for 4 hours and using a catalyst mole ratio to 5% substrate

Effect of reaction conditions in the catalytic esterification of palm fatty acid distillate to produce fatty acid methyl ester

Biodiesel or fatty acid methyl ester (FAME) obtained via esterification process is an alternative for industrial and transportation fuel. In this study, chromium-titanium mixed oxides catalyst synthesized via sol-gel method was used to catalyse the esterification of palm fatty acid distillate (PFAD) to produce FAME. Esterification was conducted in a batch reactor. The effects of reaction temperature, methanol to PFAD molar ratio, reaction time and reusability of catalyst were studied. Reaction conditions yielding the best performance of 89% FAME content were reaction temperature of 160°C, methanol to PFAD molar ratio of 3:1 and reaction time of 3 h. The catalyst can be reused for 3 times with 20% performance reduction between the first run and the third run. The results revealed that the mixed oxides of Cr-Ti is a potential heterogeneous catalyst for use in the esterification of high acid value feedstock of PFAD.