Catalyst For Transesterification Research Articles

KF/MgO used as the catalyst for transesterification of dimethyl carbonate with isosorbide to dicarboxymethyl isosorbide

KF/MgO used as the catalyst for transesterification of dimethyl carbonate with isosorbide to dicarboxymethyl isosorbide

Facile and efficient fabrication of carbon nanotube reinforced epoxy vitrimers through dynamic crosslinking

AbstractCarbon nanotubes (CNT) is an ideal candidate for reinforced epoxy vitrimer composites, however, achieving a desirable improvement of the mechanical properties is a great challenge owing to CNT is extremely easy to aggregate. In this study, well‐dispersed CNT reinforced epoxy vitrimers, namely EVD/CNT, were prepared by combining ultrasonic dispersion and dynamic crosslinking techniques, using multiple wall carbon nanotube as reinforcement filler, sebacic acid as curing agent, diglycidyl ether of bisphenol A (DGEBA) as epoxy monomer, zinc acetylacetonate as transesterification catalyst, torque rheometer (internal mixer) as dynamic crosslinking equipment. The CNT reinforced epoxy vitrimers, namely EVS/CNT, were prepared using traditional static curing method. The structure and morphology, mechanical properties and stress relaxation behavior of EVS/CNT and EVD/CNT were comparatively investigated, and the influence of CNT content on the structure and properties of EVD/CNT prepared by dynamic crosslinking method were also studied. The results indicated that dynamic crosslinking technology can stably disperse CNT into epoxy vitrimer resin matrix under continuous shear force. However, CNT experienced severe secondary agglomeration during the static curing process. When the loading amount of CNT was 2 wt%, the tensile strength and elongation at break of EVD/CNT‐2 were 3.2 times and 2.2 times higher than those of EVS/CNT‐2, respectively. The Young's modulus and glass transition temperature (Tg) of EVD/CNT‐2 (6.43 ± 1.10 MPa, 29.6°C) were also higher than those of EVS/CNT‐2 (5.46 ± 0.31 MPa, 25.4°C). Moreover, dynamic crosslinking technology greatly shortened the reaction time of CNT reinforced epoxy vitrimers, improved production efficiency and reduced reaction energy consumption, and was expected to be used for large‐scale and industrial production.

Water‐Assisted Reprocessing and Shape Programming of Epoxy Vitrimer

Water‐Assisted Reprocessing and Shape Programming of Epoxy Vitrimer

Waste snail shells-derived mixed oxide catalyst for efficient transesterification of vegetable oil: Towards sustainable biodiesel production

This study explores the transesterification process of soybean oil for the production of biodiesel, utilizing an innovative mixed oxide catalyst obtained from discarded snail shells powder. The catalyst synthesis involved a thermal treatment at 900°C for 120 min, predominantly yielding calcium oxide (CaO). In order to evaluate its properties, we carried out a thorough characterization using various analytical techniques. The study explores the impact of crucial variables on the transesterification reaction, such as reaction time (from 30 to 150 min), methanol-to-oil ratio (from 3:1–18:1), and catalyst concentration (from 0.5% to 4% by weight). Optimal conditions emerged with a 90-min reaction time, a 12:1 methanol-to-oil ratio, and a 2% catalyst loading, yielding an impressive biodiesel conversion rate of approximately 93%. The validity of biodiesel conversion was confirmed through Fourier transform infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1 H NMR). The resultant biodiesel exhibited highly favorable characteristics, including an acid value of 0.85 mg of KOH/g, a density of 886.8 kg/m3, and a viscosity of 4.6 mm2/s. These measurements align with the standards set forth in EN 14214 and ASTM D6751 regarding biodiesel quality. The utilization of waste snail shells powder as a precursor for synthesizing the mixed oxide catalyst presents a promising approach for the sustainable production of biodiesel from soybean oil, offering a sustainable and efficient approach to biofuel production.

Effect of processing conditions on the properties of vitrimerized polybutylene terephthalate prepared by reactive extrusion

This study examined the effects of continuous reactive extrusion on the properties of vitrimerized thermoplastics derived from polybutylene terephthalate (PBT). PBT formulations were prepared using epoxy (crosslinker) and zinc acetylacetonate (transesterification catalyst) to form dynamic covalent networks. Reactive extrusion was performed at different screw rotation speeds (50, 100, 200rpm) with controlled residence times to compare the effects of the shear stress during the formation of crosslinks on the vitrimer properties. The rheological behavior of the extruded vitrimerized PBT suggests that competition between chain scission and branching occurs during the dynamic crosslinking of thermoplastics. Increasing the shear stress and/or time in the extruder was found to favor chain scission over crosslinking which makes gelation unattainable. In the case of injection molded specimens, tensile and X-ray diffraction tests of vitrimerized PBT extruded at different shear stress indicated a significant relationship between the degree of crosslinking, the orientation of crystallites, and the ability of the polymer network to withstand deformation at elevated temperatures.

Diphenyl Carbonate: Recent Progress on Its Catalytic Synthesis by Transesterification

Diphenyl carbonate is one of the raw materials used for the synthesis of polycarbonate, and its green and clean production is of great importance to the non-phosgene process for polycarbonate. The production of diphenyl carbonate by transesterification is its representative process route and is considered to be one of the typical examples of a green and sustainable process for chemicals. Since the discovery of the transesterification catalyst for diphenyl carbonate in the 1970s, researchers have been committed to improving its catalytic activity and selectivity and, correspondingly, the reaction engineering process. However, thermodynamic limitations, low activity, low selectivity, and limited stability have been bottlenecks that the transesterification catalyst has not been able to completely overcome, and the improvement of the catalyst is still ongoing. Therefore, this review takes the transesterification reaction of dimethyl carbonate and phenol as a model reaction and, based on a review of the progress in catalyst research on catalytic reaction processes, tries to clarify the structure–activity relationship between catalytic active sites and catalytic performance in homogeneous and heterogeneous catalytic processes and provides an overview of the progress in catalyst synthesis and modification.

Effective transesterification of castor oil to biodiesel catalyzed by novel carbon-based calcium composite

A novel carbon-based calcium catalyst was prepared through impregnation-calcination method, and was successfully applied as an effective catalyst for transesterification of castor oil to produce biodiesel. The catalyst prepared through the calcination at 500 °C for 3 h (Ca/C-500–3) exhibited the optimal performance. The prepared carbon-based calcium catalyst had excellent crystallinity and morphology, high basicity and surface area according to the characterization analysis results. Based on the XPS analysis, the combination of CaO and C in Ca/C-500–3 could improve the oxygen ion donating ability, which was beneficial for the reaction of triglycerides with methanol. The optimum composite of carbon-based calcium catalyst (Ca/C-500–3) displayed the excellent catalytic activity in castor oil transesterification, and 95.44 % of biodiesel conversion was obtained with the following conditions: methanol to oil molar ratio of 18:1, catalyst dosage of 5 wt%, reaction temperature of 65 °C and reaction time of 3 h. The TOF indicated that Ca/C-500–3 was an efficiency catalyst. Meanwhile, the calculation results of E-factor and PMI manifested that the transesterification of castor oil to biodiesel catalyzed by Ca/C-500–3 was a green reaction. Ca/C-500–3 could retain its high catalytic activity after five reaction cycles. The LCC cost analysis results suggested that, using Ca/C-500–3 as catalyst, biodiesel production from castor oil as feedstock had lower production cost compared to other biodiesel productions. The various factors affecting the cost of producing biodiesel were investigated using sensitivity analysis. Finally, the possible mechanism of catalytic transesterification reaction using carbon-based calcium composites was revealed.

Tertiary amine-based autocatalytic transesterification epoxy vitrimer: Effect of tertiary amine structure and covalent incorporation on the properties of vitrimers

Since its first report in 2011, researches on vitrimer transesterification catalyst systems had been gradually focused on three aspects: low toxicity and low corrosion, good compatibility with resin matrix, and high catalytic performance for bond exchange reactions. However, it is difficult to obtain a catalytic system that can simultaneously meet the above three expectations. This research conducted the preparation of autocatalytic transesterification epoxy vitrimers by directly mixing small tertiary amine molecules with epoxy-anhydride systems and covalent incorporating tertiary amine structures into curing systems. And the influence of tertiary amine structures and covalent incorporation on the various properties of vitrimers was also discussed. A tertiary amine promoter composed of isofunctional group ratio reaction from di-n-hexamine and epoxy resin provided by this research overcame the problem of poor compatibility between tertiary amine and epoxy resin, introduced a highly active catalytic structure into vitrimer curing system. And the result indicated that the vitrimer prepared according to our new strategy had excellent comprehensive performance. In conclusion, a new idea of covalent incorporation was proposed to provide ideas and inspiration for the development of new tertiary amine-based autocatalytic transesterification epoxy vitrimers.

Synthesis of Guanidine and Its Deposition on Bacterial Cellulose as Green Heterogeneous Catalyst for Transesterification to Methyl Esters

Green catalysts used in the transesterification reaction of biodiesel must have biodegradability and non-toxicity as their main characteristics, being thus friendly to the environment, since they perform in processes in which the content of CO2, which is increasing from year to year, should be reduced. As a consequence, their manufacture can be extremely rigorous. This work presents the two-step construction, synthesis, and deposition of such a green heterogeneous catalyst and its testing in the catalysis of the transesterification of triglycerides with methanol, resulting in methyl esters. A CSTR-type reactor was used to perform transesterification, and the biodiesel yields obtained had values in the range of 91.7–95.7%, using 2, 3, and 4 g/g catalyst to oil, under conditions like those for obtaining commercial biodiesel in homogeneous catalysis, i.e., a 65 °C process temperature and a 4:1, 5:1 or 6:1 methanol-to-oil molar ratio.

Superior heat‐resistant polylactide/poly(butylene succinate) blend fibers via in‐situ reactive compatibilization

AbstractBlending poly(butylene succinate) (PBS) with polylactide (PLLA) has proven effective in improving heat resistance of PLLA fibers. Unfortunately, it remains challenging to maintain good spinnability for PLLA/PBS blends with high content of PBS with which further improved heat resistance could be anticipated. In this study, reactive melt‐extrusion was devised to in‐situ generate PLLA‐PBS copolymers by introducing zinc acetate as a transesterification catalyst into PLLA/PBS blends. The compatibility between the PLLA and PBS phases was greatly improved by the formation of PLLA‐PBS copolymers, resulting in excellent melt‐spinnability even for the PLLA/PBS blends with high PBS content up to 20 wt%. In addition, an increase in crystallinity of PLLA was achieved in PLLA/PBS blend fibers, thanks to the enhanced compatibility. More importantly, the presence of PBS nuclei retarded the molecular orientation of the amorphous PLLA phase, consistent with the effective results from the relaxation heat‐setting treatment. These led to an exceptionally improved heat resistance of the PLLA/PBS blend fibers. As an encouraging result, the boiling water shrinkage was significantly reduced from ca. 20% for neat PLLA fibers to 3.7% for the PLLA/PBS blend fibers with 20 wt% PBS content. These findings may open up a facile and effective route to develop PLLA/PBS blend fibers showing sound spinnability, greatly improved heat resistance and softness.

Synthesizing a transesterification catalyst via a condensation reaction and assessment of the mechanism using density functional theory

AbstractBACKGROUNDA solid acid (SPEI–EN–OHCMs) having dendritic –NH2 groups was prepared via oxidation of hydrothermal carbon microspheres (OHCMs) followed by a condensation reaction with the –NH2 groups of polyethyleneimine and sulfonation. The mechanism by which –COOH groups on the surfaces of OHCMs reacted with these –NH2 groups was assessed using density functional theory (DFT).RESULTActivation using a combination of 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride (EDC) and N‐hydroxysuccinimide (NHS) was found to promote the formation of amide bonds such that –NH2 groups were bonded to the microsphere surfaces. This effect provided more bonding sites for –SO3H groups. The DFT results indicated that the energy barrier on the potential energy surface in the presence of EDC and NHS was lowered by 18.1 kcal mol−1. X‐ray photoelectron spectroscopy analyses also confirmed the introduction of –NH2 groups followed by –SO3H groups onto the surfaces of the OHCMs. The concentration of surface acid sites on SPEI–EN–OHCMs was found to be as high as 11.8 mmol g−1. Thermogravimetric data and elemental analysis results showed that the –SO3H groups on the SPEI–EN–OHCM surfaces were thermally stable below 180 °C.CONCLUSIONThe SPEI–EN–OHCMs catalyst was used to promote the transesterification reaction of waste frying oil with methanol. A trial with a methanol‐to‐oil molar ratio of 10:1 at 110 °C for 4 h gave a fatty acid methyl ester (FAME) yield of 92.3%. After four reuses, an SPEI–EN–OHCMs specimen provided a FAME yield of 54.3%. © 2024 Society of Chemical Industry (SCI).

The Kinetic Study of the Influence of Common Modifiers on the Curing Process of Epoxy Vitrimers.

An analysis of the influence of common modifiers on the kinetics of the curing process of epoxy-anhydride vitrimers was carried out. As common modifiers to enhance the "vitrimeric" nature of the material, zinc acetylacetonate as a transesterification catalyst and glycerol as a modifier of hydroxyl group content were chosen. The curing process of all obtained compositions was studied by differential scanning calorimetry (DSC) followed by the application of the isoconversional approach. It was shown that additives significantly affect the curing process. The resulting cured polymers were shown to be chemically recyclable by dissolution in the mixture of ethylene glycol and N-methylpirrolidone in a volume ratio of nine to one. The introduction of both zinc acethylacetonate and glycerol to the neat formulation led to a decrease in the dissolution time by 85.7% (from 35 h for the neat epoxy-anhydride formulation to 5 h for the modified formulation). In order to show the opportunity of the secondary use of recyclates, the mixtures based on the basic composition containing 10 wt. % of secondary polymers were also studied. The introduction of a recycled material to neat composition led to the same curing behavior as glycerol-containing systems.

Kinetics of Homogeneous Reaction of Potassium Methoxide Based on K2CO3 Catalyst in Transesterification of RBDPO to Biodiesel

Biodiesel production is generally catalyzed by potassium methylate or sodium methylate catalysts based on KOH and NaOH and these catalysts are still imported. The search for a cheap and effective catalyst continues to be carried out by researchers. One of the catalyst support materials currently in use involves impregnating K2CO3 with various substances, resulting in a heterogeneous catalyst. In this study, it was tried to use K2CO3 dissolved in methanol to produce a homogeneous potassium methylate catalyst. Potassium methylate-based homogeneous catalyst K2CO3-methanol is proven to have a very high function in the transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) into biodiesel, this is evidenced by the use of a catalyst percentage of 2% w and 30% w methanol to the weight of RBDPO resulting in an acid content in biodiesel of only 0.12% and a total glycerol of 0.124% in reaction time 3 hours, with the purity of the methyl ester in biodiesel reaching 98.80%. Meanwhile, for the calculation of homogeneous reaction kinetics, a reaction rate equation is produced where the order of the RBDPO transesterification reaction is order 2 (two) and the reaction rate constant is 0.0044.

Design of anti-saponification Ca-based catalyst with porous-shell structure from crustacean waste for biodiesel production

The rapid development of the biodiesel industry is of significant importance for achieving carbon emission reduction in the transportation sector. However, the presence of trace amounts of water in the feedstock during biodiesel synthesis may lead to severe saponification reactions, thereby reducing the yield of fatty acid methyl esters. In this study, based on our exploration of the characteristic of porous carbon to absorb moisture from the environment, we synthesized a CaO catalyst with porous carbon coating via discarded shrimp shell biomass. Because the carbonization temperature of organic matter in shrimp shells is lower than the decomposition temperature of CaCO3, the CO2 generated during pyrolysis can erode the pyrolytic carbon and form porous structure. The mesoporous carbon shell facilitates the diffusion of oil and methanol molecules while adsorbing moisture in the alcohol phase. This structure effectively minimizes the interaction between CaO and water, thereby suppressing saponification reactions and ensuring the smooth progression of the desired transesterification reaction. Through a series of physicochemical characterizations, the structure and water absorption performance of the catalyst were confirmed. The as-prepared CaO@PC-900 catalyst demonstrated the ability to maintain a biodiesel yield of over 85% in a reaction system with a water content of 3%, significantly surpassing the performance of commercial CaO and previously reported Ca-based solid bases. This work provides a new approach to the design of anti-saponification transesterification catalysts, while also offering a novel pathway for the synthesis of porous carbon from discarded crustacean biomass.

Self‐healing and reprocessing of saturated hydroxyl‐terminated polybutadiene‐based networks enabled by dynamic covalent chemistry

AbstractHydroxyl‐terminated polybutadiene (HTPB) is found in many applications due to its ease of manufacturing, useful mechanical properties over a wide temperature range, and reactive hydroxyl chain ends. Typically, HTPB is crosslinked with isocyanates to form polyurethane thermosets. Limitations of this approach include the use of toxic isocyanates and the oxidative instability of backbone alkenes. In this work, saturated HTPB is used to form reprocessable covalent adaptable networks that are capable of stress relaxation and reprocessing, without relying on isocyanates or unstable alkenes. This approach introduces dynamic chemistry to the HTPB network via chain extension and subsequent crosslinking with 4‐methyl caprolactone (4mCL) and a novel bislactone crosslinker. Using benzenesulfonic acid (BSA) as a transesterification catalyst, stress relaxation times range from 150 to 8 min at temperatures of 70 to 100 °C. Despite crosslinking, these networks behave elastically, as evidenced by strain‐at‐break values of 93% for pristine samples, and dynamically, as shown by a strain‐at‐break of 72% after reprocessing the damaged samples. Shape reprogramming is also demonstrated by straining the crosslinked networks and heating to elevated temperatures where bond exchange occurs. These findings illustrate the advantageous properties that can be achieved by using cheap commodity building blocks to achieve dynamic properties. We anticipate that valorizing commodity polymers into reprocessable thermosets will be of utility in applications that lack other viable recycling pathways.

Sustainable biodiesel production from waste olive oil: Utilizing olive pulp-derived catalysts for environmental and economic benefits

This paper introduces an environmentally and economically advantageous biodiesel production method using waste olive oil and pulp-derived catalysts. It tackles the critical issue of olive waste management by reusing discarded materials, reducing pollution, and minimizing landfill use. This sustainable approach preserves natural resources and reduces the carbon footprint associated with waste disposal. Olive pulp-derived catalysts offer a cost-effective and eco-friendly alternative to traditional catalysts, enhancing the economic viability of biodiesel production. Despite its low oil content, the waste olive pulp (WOP) is efficiently utilized for biodiesel production. The patent explores Sulfonated Carbon (SC) derived from dried olive pulp, serving as a robust acidic catalyst for transesterification. Characterization techniques comprising XRD, FTIR, and FESEM analyze SC properties. Biodiesel development optimization from waste olive oil (WOO) employs Response Surface Methodology (RSM), resulting in optimal conditions: a methanol-to-oil molar ratio of 15:1, a 60 °C reaction temperature, a 5-h transesterification time, and a 4% catalyst dose, yielding an impressive 94% biodiesel yield. The biodiesel's chemical structure is confirmed through analytical tools such as FT-IR, 1HNMR, and 13CNMR.In summary, this study highlights the potential of sulfonated carbon as a catalyst for sustainable biodiesel generation from waste olive oil. It offers a safe, efficient, and environmentally friendly alternative to traditional catalysts, delivering both environmental and economic benefits.

Application of Sodium Silicate from Palm Leaf Ash as Heterogeneous Catalyst in Transesterification of Palm Oil

This research aims to synthesize sodium silicate based on palm leaf ash as a heterogeneous catalyst for making biodiesel from refined, bleached, deodorized, palm oil (RBDPO). Silica was obtained by calcining palm leaf at a temperature of 700°C for 3 hours, followed by washing using 1 N HCl solution. Synthesis of sodium silicate catalyst was carried out by varying the mole ratio of NaOH:SiO2. The best catalyst was obtained at a NaOH:SiO2 molar ratio of 1.5:1, with a biodiesel yield of 74.468% and an ester content of 97.293%. The sodium silicate catalyst produced in this research performed a good stability by showing high recycling uses. The catalyst could be used up to three times without regeneration produced biodiesel with a yield of 40.018%.

Studies on Mg–Ba mixed oxide catalysts for continuous glycerol transesterification to glycerol carbonate

Mg–Ba mixed oxide catalysts are highly active and stable for continuous production of glycerol carbonate by transesterification of glycerol.

An anhydride -cured degradable epoxy insulating material exhibiting recyclability, reusability, and excellent electrical performance

We synthesized a high-performance epoxy insulating material that can be recycled and reused using triethanolamine as a transesterification catalyst co-accelerator. The new epoxy can be physically recovered through hot-pressing and regenerated via chemical degradation.

LTA zeolites as catalysts for transesterification of glycerol with dimethyl carbonate

The objective of this study was to investigate the use of LTA-structured zeolites as catalysts for synthesizing glycerol carbonate through the transesterification of glycerol with dimethyl carbonate, under mild reaction conditions. To evaluate the catalysts, a range of characterization techniques, including XRD, AES, SEM, TPD-NH3, TPD-CO2, and FT-IR with probe molecules like pyridine and pyrrole, along with elemental analysis, were employed. The investigation focused on various forms of LTA-structured zeolites (with K, Na, and Ca cations) to assess their impact on transesterification activity, with particular attention to the type of ion utilized and their basicity. Among these zeolites, K-Na-LTA (3A) zeolites demonstrated the most promising performance, achieving glycerol conversion rates ranging from 55 % to 77 %. Moreover, increasing basicity in the 3A zeolites led to higher glycerol conversion and glycerol carbonate yield. Encouragingly, all tested samples exhibited 100 % selectivity, exclusively producing the desired glycerol carbonate. However, during catalyst recycling, the decrease in glycerol conversion was observed, likely due to the leaching of active sites from the catalyst into the reaction medium. Methanol, being a one of the products, was identified as a potential agent responsible for the removal of potassium ions, during this process.