Catalyst For Esterification Research Articles

Arenesulfonic Acid-Functionalized Bentonite as Catalyst in Glycerol Esterification with Acetic Acid

The present study is focused on the synthesis of arenesulfonic acid-functionalized bentonite as a catalyst to produce monoacetin, diacetin, and triacetin from glycerol and acetic acid using toluene as solvent and a water removing agent. The best conditions for the present reaction with acetic acid were an acetic acid:glycerol:toluene molar ratio of 7:1:1.4, 100 °C, and 0.074 wt % of catalyst (based on the total weight of glycerol). Under the reaction conditions, 96% glycerol conversion was achieved within 0.5 h from the start of the reaction. The maximum selectivity of 66% and 74% were achieved for diacetin and triacetin after 0.5 and 3 h of reaction, respectively, without formation of any byproduct. The arenesulfonic acid-functionalized bentonite was characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, N2 adsorption/desorption experiments (Brunauer, Emmett and Teller, BET, method), field emission scanning electron microscopy, and the surface acidity was determined by back titration. Without significant treatment, the catalyst was reusable for 5 consecutive runs.

Adaptive neuro-fuzzy inference system-genetic algorithm vs. response surface methodology: A case of optimization of ferric sulfate-catalyzed esterification of palm kernel oil

Abstract Ferric sulfate-catalyzed esterification process for palm kernel oil (PKO), which had an initial acid value (AV) of 22 ± 0.1 mg KOH/g oil, was modeled using response surface methodology (RSM) and adaptive neuro fuzzy inference system (ANFIS). The process parameters investigated in the AV reduction of the oil were methanol-to-oil ratio (2:1–3:1), catalyst loading (6–10 w/v) and reaction time (15–25 min) using Box Behnken design of RSM. The developed ANFIS and RSM models were both subjected to various statistical evaluation and they both showed high degree of accuracy based on the high values of coefficient of determination ( R 2 ) of 0.9662 and 0.9039 for ANFIS and RSM, respectively and low values of mean absolute error of prediction (MAE) 0.0506 and 0.1506, and average absolute deviation (AAD) of 2.3665 and 7.1179 for ANFIS and RSM, respectively. To minimize the AV for the PKO, the process parameters investigated were optimized using RSM and ANFIS coupled with genetic algorithm (GA). Optimum values of methanol-to-oil ratio of 2.96:1, catalyst amount of 6 w/v and reaction time of 15 min with a corresponding AV of 1.05 mg KOH/g oil (95.2% AV reduction) were established using ANFIS-GA, while the values obtained using RSM were methanol-to-oil ratio of 2:1, catalyst amount of 6 w/v and reaction time of 25 min with a corresponding AV of 1.54 mg KOH/g oil (93.0% AV reduction). Based on the statistical indicators employed for this work, ANFIS was a better prediction tool than RSM while GA outperformed RSM in the optimization of the esterification process. Ferric sulfate proved to be a good catalyst for PKO esterification.

Progress on Zeolite-membrane-aided Organic Acid Esterification

Esterification is a common route to produce carboxylic acid esters as important intermediates in chemical and pharmaceutical industries. However, the reaction is equilibrium limited and needs to be driven forward by selective removal one of the products. There have been some efforts to selectively remove water from reaction mixture via several separation processes (such as pervaporation and reactive distillation). Integrated pervaporation and esterification has gained increasing attention towards. Inorganic zeolite is the most popular material for pervaporation due to its high chemical resistant and separation performance towards water. Zeolite also has proven to be an effective material in removing water from organic compound. Zeolite can act not only as selective layer but also simultaneously act as a catalyst on promoting the reaction. Hence, there are many configurations in integrating zeolite membrane for esterification reaction. As a selective layer to remove water from reaction mixture, high Si/Al zeolite is preferred to enhance its hydrophilicity. However, low Si/Al zeolite is unstable in acid condition due to dealumination thus eliminate its advantages. As a catalyst, acid zeolites (e.g. H-ZSM-5) provide protons for autoprotolysis of the carboxylic acid similar to other catalyst for esterification (e.g. inorganic acid, and ion exchange resins). There are many studies related to zeolite membrane aided esterification. This paper will give brief information related to zeolite membrane role in esterification and also research trend towards it.

High-efficiency oxidative esterification of furfural to methylfuroate with a non-precious metal Co-N-C/MgO catalyst

From both fundamental and practical perspectives, the production of chemicals from biomass resources using high-efficiency non-precious metal catalysts is important. However, many processes require addition of stoichiometric or excess quantities of base, which leads to high energy consumption, leaching problems, and side reactions. In this study, we investigated the high-efficiency oxidative esterification of furfural to methylfuroate by molecular oxygen with a Co-N-C/MgO catalyst. The catalyst was prepared by direct pyrolysis of a cobalt(II) phenanthroline complex on MgO at 800 °C under N 2 atmosphere. From furfural, 93.0% conversion and 98.5% selectivity toward methylfuroate were achieved under 0.5 MPa O 2 with reaction at 100 °C for 12 h without a basic additive. The conversion and selectivity were much higher than those obtained with cobalt catalysts produced by pyrolysis of a cobalt(II) phenanthroline complex on activated carbon or typical basic supports, including NaX, NaY, and CaO. X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and experimental results revealed that the high efficiency of Co-N-C/MgO for production of methylfuroate was closely related to the cobalt-nitrogen-doped carbon species and its catalytic ability in hydrogen abstraction. In contrast, Co-N-C(HCl) that synthesized by removing MgO with HCl from Co-N-C/MgO, as the catalyst produced mainly an acetal as a condensation product, and chloride ions had a negative effect on the oxidative esterification. Although the catalytic performance of the cobalt-nitrogen-doped carbon species was greatly affected by HCl treatment, it could be recovered to a great extent by addition of MgO. Moreover, changes in the oxygen pressure hardly affected the oxidative esterification of furfural with Co-N-C/MgO. This study not only provides an effective approach to prepare methylfuroate, but also for designing high-performance non-precious metal catalysts for the oxidative esterification of biomass-derived compounds. The non-precious metal catalyst Co-N-C/MgO showed high efficiency in the oxidative esterification of furfural to methylfuroate (93.0% conversion and 98.5% selectivity). The reaction with the catalyst Co-N-C(HCl) proceeded via a condensation pathway with acetal as the dominant product.

Synthesis of Biolubricant Trimethylolpropane Trioleate and Its Lubricant Base Oil Properties

Trimethylolpropane trioleate (TMPTO) could significantly reduce environmental pollution compared to mineral oils. In this study, oleic acid (OA) and trimethylolpropane (TMP) were used to synthesize TMPTO, and the synthesis process was optimized by single-factor experiments to obtain the highest yield. First, two kinds of operating conditions (vacuum distillation and atmospheric reflux) were compared, and then four kinds of catalysts were investigated to select the most efficient catalyst in esterification. Afterward, five reaction parameters were investigated, and the optimal conditions obtained were as follows: catalyst/TMP, 3.2:1 (molar ratio) 2% (w/w) OA/TMP; temperature, 180 °C; reaction time, 3 h; and vacuum degree, 0.095 MPa. Under the optimized conditions, the TMP conversion rate reached up to 92.8%. Furthermore, TMPTO was confirmed by Fourier transform infrared spectroscopy (FTIR). Finally, the typical properties of the product were evaluated, including the kinematic viscosity at 40 and 100 °C, vi...

Zr-modified hierarchical mordenite as heterogeneous catalyst for glycerol esterification

Hierarchical mordenite catalysts were prepared by HF and NH4F etching. Materials' zirconia modification was performed by incipient wetness impregnation in order to vary surface acidity type and strength. XRD, N2 physisorption, solid-state NMR and UV–Vis spectroscopies were applied for characterization. Acidic properties of the obtained materials were investigated by TPD of adsorbed ammonia and FT-IR spectra of adsorbed pyridine. Catalytic performance was studied for the glycerol esterification with acetic acid. Zr increased reaction turnover activity compared to raw zeolite substrate due to abundant Brönsted and Lewis moiety presence. The demonstrated biomass valorization processes to bio-based platform chemicals are of interest, as they employ biodiesel production waste.

Preparation and characterization of SO42 −/FexAl1 − xPO4 solid acid catalysts for caprylic acid esterification

A series of SO42−/FexAl1−xPO4 solid acid catalysts were prepared and characterized by means of XRD, FE-SEM, elemental analysis, N2 adsorption–desorption, XPS, NH3-TPD, pyridine adsorption FT-IR and ion exchange/titration. Their catalytic performances were evaluated by the esterification of caprylic acid with ethanol. Experimental results revealed that the doping of iron can markedly enhance the acidic properties of the SO42−/AlPO4, thereby boosting its catalytic activity in esterification. The maximum caprylic acid conversion of 92.4% was achieved over the iron doped catalysts. Moreover, the incorporation of iron has also greatly elevated the stability of SO42−/AlPO4 during repeated catalytic cycles.

A potential “green” organotin: Bis-(methylthiopropyl)tin dichloride, [MeS (CH2)3]2SnCl2

The tetravalent organotin compound [MeS(CH2)3]2SnCl2, 1, has been synthesized in high yield and structurally characterized as being hexa-coordinate at tin with two intramolecular Sn-S bonds. The specific structure has been shown by theoretical calculations to be the low energy geometric structure available, and the differences associated with the experimental and calculated Sn-S bond lengths ascribed to crystal packing issues. The intramolecular Sn-S bonding produces a benign organotin compound with respect to its interactions with human natural killer cells; however, this blocking of coordination sites at Sn does not reduce its capacity to act as an efficient esterification catalyst.

Natural Phosphate Supported Titania as a Novel Solid Acid Catalyst for Oleic Acid Esterification

In the present study, a novel solid acid catalyst based on titanium dioxide (2.5–10 wt %) supported on natural phosphate (TiO2/NP) was prepared by a sol–gel process, and 10 wt % loaded catalyst was characterized by several physicochemical techniques. The performances of the synthesized catalyst were investigated in esterification of oleic acid with methanol. The catalytic performance was screened under different reaction conditions, namely, loading amount of TiO2, calcination temperature, molar ratio of methanol to oleic acid, reaction temperature, and amount of catalyst. Under optimal conditions, the catalyst loaded with 10 wt % TiO2 and calcined at 800 °C showed the highest oleic acid conversion of 87%. The catalyst showed a good stability under high reaction temperature and can be reused without severe loss of activity. As a versatile application, the TiO2(10)/NP catalyst exhibits a good ability for the esterification of free fatty acids in a highly acidic feedstock.

Retention and sustained release of fragrance by Cyclodextrin functionalized cotton fabric modified using maleic anhydride

Abstractβ‐cyclodextrin(CD) was incorporated in cotton fabric following pad‐dry‐cure technique employing maleic anhydride as modifying agent under the dual influence of free radical polymerization catalyst ammonium peroxodisulfate [(NH4)2S2O8] and esterification catalyst tetrasodium pyrophosphate (Na4P2O7). β‐cyclodextrin(CD) can be esterified if treated with maleic anhydride (an unsaturated dicarboxylic acid) due to the presence of hydroxyl groups in β‐cyclodextrins and also such compound can form inclusion complex with essential oils. The retention of essential oil and its sustained release after repeated post wash treatments was determined quantitatively by UV–vis spectrophotometry.

Mesoporous aluminosilicate: efficient and reusable catalysts for esterification of sec-butanol with acetic acid

Esterification of acetic acid with sec-butanol to produce sec-butyl acetate has been systematically carried out by using mesoporous (3–9 nm size) aluminosilicate (meso-AS) catalysts (surface area 327–578 m2 g−1) derived from Na-montmorillonite by controlled HCl acid activation. High catalytic activity up to 89% conversion with nearly 100% selectivity towards sec-butyl acetate is observed. The effect of reaction temperature, mole ratio of reactants and catalyst concentration on esterification reactions were studied. The catalyst could be recycled and reused several times without significant loss of their catalytic activities. The catalysts were characterized by pyridine adsorbed FT-IR, XRD, SEM-EDX, MAS-NMR, surface area (BET) and TPD analysis.

Functionalization of MWCNT by –SO3H and –COOH Groups and Their Application as Solid Acidic Catalysts for Esterification of Waste Chicken Fat

Functionalization of MWCNT by –SO3H and –COOH Groups and Their Application as Solid Acidic Catalysts for Esterification of Waste Chicken Fat

Effect of water and lipophilic alcohols or amines on the 4‐dodecylbenzenesulfonic acid‐catalyzed esterifications, trans‐esterifications, and amidations

4‐Dodecylbenzenesulfonic acid (DBSA) was employed in the esterification of oleic acid (OA) and the trans‐esterification of oleic oil (OO) with 1‐butanol as alcohol in the presence of various degrees of excess water. Under these conditions DBSA was found to be a highly active esterification catalyst regardless of excess water content, but was found to be a less effective for trans‐esterification reactions. Lipophilic alcohols of differing straight and branched C3‐6 chains were also tested on mixtures of OA/water (1:1) in DBSA‐catalyzed esterifications; OO/water (1:1) in trans‐esterifications; and OA/OO/water (1:1:1) in simultaneous esterifications and trans‐esterifications. While longer straight chain alcohols generally gave a two‐fold increase in yield of their corresponding alkyl oleates to 80%+, we observed a doubling from 30–50% to 60–95% of alkyl oleate yield for the OO/OA/water mixture. DBSA‐catalyzed amidations of OO and methyl oleate emulsions in water were conducted with 1‐butyl and 1‐heptyl amine where it was found that the more lipophilic the ester moiety the higher the yield of alkyl amide.Practical applications: The practical advantages of DBSA as catalyst are high conversions to the desired product along with its tolerance to high quantities of water, emulsified within the lipid material. A capacity to transform a range of substrates with varying lipophilic character in a range of condensation reactions. In addition, we demonstrate that esterification and trans‐esterification reactions could be performed simultaneous and in the presence of high quantities of water. This is of direct interest to the transformation of waste sources of lipids that often contain a mixture of triglycerides and free fatty acids in various concentrations, emulsified with waste water. Furthermore, we demonstrate that all of the value‐added products/co‐products can be separated by an effective and industrially relevant methodology, including recovery of the DBSA catalyst as well as the water and water soluble co‐products, such as glycerol.A 4‐Dodecylbenzenesulfonic acid (DBSA) is demonstrated to be an effective polyvalent catalyst for the recovery of aqueous emulsified lipids by conversion into value‐added products. DBSA proved to be a polyvalent catalyst showing high activity using a range of substrates, performing esterification, trans‐esterification, and amidations reactions efficiently despite the potential detrimental presence of high water loadings. The commercial incentive of our system is the phase separation of the product mixture into the converted lipids for use as biofuels and glycerol for resale as a fine chemical.

Sol‐immobilized vs deposited‐precipitated Au nanoparticles supported on CeO2 for furfural oxidative esterification

AbstractBACKGROUNDThe non‐edible nature of lignocellulose makes this an important raw material for future biorefineries. This work concerns the oxidative esterification of furfural (a C5 compound) to alkyl furoates, which find applications in the fine chemical industry.RESULTSVery efficient Au/CeO2 catalysts for furfural oxidative esterification were prepared by deposition of gold colloids using polyvinyl alcohol as protective agent. The catalysts provided complete conversion and selectivity without the presence of a base. Sol‐immobilized catalysts displayed better catalytic performances than Au/CeO2 prepared by deposition–precipitation (74% conversion). It was proposed that polyvinyl alcohol molecules act not only as gold stabilizer, but they leave ceria support uncovered and available for catalysis. The reaction is extremely sensitive to temperature, but can be carried out at very low pressures. Sol‐immobilized catalysts do not require any preliminary calcination to be activated and can be recovered by simple filtration: no oxidation of the exhausted catalyst is required for at least six catalytic runs.CONCLUSIONThe new catalyst is active, selective, recyclable and suitable for an industrial chemistry application based on renewable resources. Furoate ester can be obtained with optimal yields by a greener process than is presently used. © 2017 Society of Chemical Industry

High purity FAU-type zeolite catalysts from shale rock for biodiesel production

FAU-type zeolite was prepared using Irish shale rock and tested as a catalyst in the liquid-phase esterification of oleic acid (a model test reaction for biodiesel production). A systematic study was conducted (over the stated preparation ranges) by varying the water:shale ratio (4:1–15:1 by mass), and mixing (1–24h), aging (6–48h) and hydrothermal treatment times (6–72h) to determine the optimal parameters. XRD confirmed that the product purity was highly dependent on the experimental conditions used. The BET surface area of the calcined FAU-type zeolite was 571m2g−1 and its crystal purity was comparable to that of a commercial zeolite Y. The prepared zeolite was catalytically active in the esterification of oleic acid with ethanol reaching a maximum of 78% conversion after 90mins, which is practically identical to that recorded for commercial zeolite Y.

Esterification of oleic acid to biodiesel over a 12-phosphotungstic acid-based solid catalyst

A 12-phosphotungstic acid (PTA)-based esterification catalyst was prepared by modifying PTA with 1,2,3-trizaole-4,5-dicarboxylic acid (TDA). The obtained TDA-PTA sample was characterized with XRD, IR, SEM, TG and potentiometric titration techniques, and its catalytic properties for esterification of oleic acid with methanol were studied. In addition, the effects of reaction conditions, including catalyst amount, oleic acid/alcohol molar ratio, reaction time and reaction temperature, on its catalytic performance were investigated. After modification with TDA, although the Keggin structure of PTA is kept and the sample shows strong acidity, the particle morphology changes to regular spheres. In particular, the sample exhibits high catalytic activity and stability in esterification of oleic acid with methanol. The modification of PTA by TDA effectively prevents PTA from dissolving in the reaction mixture, and thus, the TDA-PTA can be recycled at least six runs without severe loss of catalytic activity, showing that it is a good heterogeneous catalyst for esterification.

Octyl Co‐grafted PrSO3H/SBA‐15: Tunable Hydrophobic Solid Acid Catalysts for Acetic Acid Esterification

AbstractPropylsulfonic acid (PrSO3H) derivatised solid acid catalysts have been prepared by post‐modification of mesoporous SBA‐15 silica with mercaptopropyltrimethoxysilane (MPTMS), and the impact of co‐derivatisation with octyltrimethoxysilane (OTMS) groups to impart hydrophobicity to the catalyst was investigated. Turnover frequencies (TOFs) for acetic acid esterification with methanol increase with PrSO3H surface coverage across both families, suggesting a cooperative effect between adjacent acid sites at high acid site densities. Esterification activity is further promoted upon co‐functionalisation with hydrophobic octyl chains, with inverse gas chromatography (IGC) measurements indicating that the increased activity correlates with decreased surface polarity or increased hydrophobicity.

Sulfonic Acid-Functionalized Solid Acid Catalyst in Esterification and Transesterification Reactions

The recent development of an environmentally benign solid acid catalyst has been a relatively cutting-edge area of research in the synthesis of value added esters and biodiesel. Solid acid catalysts are economically viable, effective, and environmentally amicable than conventional homogeneous catalysts and reusability of the catalyst is another advantage of these catalysts. The applicability of sulfonic acid-functionalized solid acid catalysts in the well-known esterification and transesterification reactions for the synthesis of esters and biodiesel, respectively along with their reusability aspect are discussed in this review.

Highly efficient (CoOx-N@C, PANI) nanopowder derived from pyrolysis of polyaniline grafted cobalt acetate for oxidative methyl esterification of benzyl alcohols

Nitrogen doped carbon supported cobalt nanopowder (CoOx-N@C, PANI) obtained from pyrolysis of polyaniline (PANI) grafted cobalt(II)acetate was found to be highly active heterogeneous catalyst for oxidative esterification of alcohols using molecular oxygen as oxidant. The nanopowder was found to be more active than homogeneous as well as heterogeneous polyaniline grafted Co(II)acetate catalyst and could be efficiently reused for several runs without any significant loss in activity.

Discovery of Multicomponent Heterogeneous Catalysts via Admixture Screening: PdBiTe Catalysts for Aerobic Oxidative Esterification of Primary Alcohols.

In the present study, we demonstrate the utility of "admixture screening" for the discovery of new multicomponent heterogeneous Pd catalyst compositions that are highly effective for aerobic oxidative methyl esterification of primary alcohols. The identification of possible catalysts for this reaction was initiated by the screening of simple binary and ternary admixtures of Pd/charcoal in combination with one or two metal and/or metalloid components as the catalyst. This approach permitted rapid evaluation of over 400 admixture combinations for the oxidative methyl esterification of 1-octanol at 60 °C in methanol. Product yields from these reactions varied widely, ranging from 2% to 88%. The highest yields were observed with Bi-, Te-, and Pb-based additives, and particularly from those containing both Bi and Te. Validation of the results was achieved by preparing specific PdBiTe catalyst formulations via a wet-impregnation method, followed by application of response surface methodology to identify the optimal Pd-Bi-Te catalyst stoichiometry. This approach revealed two very effective catalyst compositions: PdBi0.47Te0.09/C (PBT-1) and PdBi0.35Te0.23/C (PBT-2). The former catalyst was used in batch aerobic oxidation reactions with different primary alcohols and shown to be compatible with substrates bearing heterocycle and halide substituents. The methyl ester products were obtained in >90% yield in nearly all cases. Implementation of the PBT-2 catalyst in a continuous-flow packed-bed reactor achieved nearly 60 000 turnovers with no apparent loss of catalytic activity.