Carbon-based Solid Acid Catalyst Research Articles

Increased flexibility to improve the catalytic performance of carbon-based solid acid catalysts

AbstractThe correlation between catalytic performance and the structure of a carbon-based solid acid (G/F-1/x), an amorphous carbon-bearing SO3H group, was investigated. Concentrated sulfuric acid was used to carbonize and sulfonate the mixed graphene and fructose powder for the preparation of carbon-based solid acid catalysts with different cross-linked structures. The results showed that the catalyst with a higher fructose loading amount presented higher catalytic performance. The catalytic performance improvement could be attributed to a high density of SO3H groups and the fast diffusion of reactants and products enabled by a flexible carbon network. The best furfural yield was obtained up to 69.4% when the weight of graphene and the fructose loading ratio was 1:4.

Oleic acid esterification with methanol to methyl oleate under light irradiation using modified alginate capsules loaded with a solid acid catalyst

Sulfated ZrO2 and amorphous carbon-based solid acid catalysts were prepared by a literature method and were estimated to contain 54 and 240 μmol g-cat−1 acid sites, respectively. The capsule shell was modified by various methods to increase its permeability to oleic acid, and methoxy functionalization of the alginate shell with methanol gave the biggest increase and also improved the oleic acid esterification to methyl oleate by the capsules loaded with the solid acid catalyst. The amount of solid acid catalyst loaded in the capsule was optimized, and the capsules loaded with the amorphous carbon-based solid acid catalyst showed a higher methyl oleate formation rate and yield than the capsules loaded with sulfated ZrO2 and active carbon powder under light irradiation. This is probably because the number of acid sites on the amorphous carbon-based catalyst was greater than that on the sulfated ZrO2 catalyst. In addition, the amorphous carbon-based catalyst was directly heated under light irradiation because it was black, whereas the sulfated ZrO2 catalyst was heated by the reaction media that was heated by the active carbon powder absorbing the irradiated light.

Critical Review on the Preparation of Platform Compounds from Biomass or Saccharides via Hydrothermal Conversion over Carbon-Based Solid Acid Catalysts

Critical Review on the Preparation of Platform Compounds from Biomass or Saccharides via Hydrothermal Conversion over Carbon-Based Solid Acid Catalysts

Valorization of de-oiled microalgal biomass as a carbon-based heterogeneous catalyst for a sustainable biodiesel production

In this study, a novel carbon-based solid acid catalyst was synthesized by carbonization of de-oiled microalgal biomass followed by sulfonation. The effect of catalyst synthesis conditions such as carbonization temperature, sulfonation time, and H2SO4 concentration on the surface acidity of the catalyst and free fatty acid conversion was determined. The de-oiled microalgal biomass-based solid acid (DMB) catalyst was predominantly composed of carboxylic, phenolic, and sulfonic groups as indicated by the FTIR analysis and supported by the XPS analysis. The catalyst was further characterized by various methods to determine its physiochemical properties. A maximum fatty acid methyl ester (FAME) yield of 94.23% for microalgal oil (AO) and 96.25% for waste cooking oil (WCO) was obtained under optimized transesterification conditions. The catalyst exhibited high catalytic activity (FAME yield >90%) until the fourth cycle. Most of the biodiesel properties were within the permissible limit of EN 14,212 and ASTM D6751 standards.

Carbon-based solid acid catalyst derived from Undaria pinnatifida and its application in esterification

In this study, solid acid catalysts were prepared from a marine biomass, Undaria pinnatifida, also known as wakame, which is one of the hundred most invasive species worldwide. Carbonaceous materials from U. pinnatifida were prepared using sequential carbonization methods of pyrolysis and hydrothermal carbonization. The influence of these two carbonization methods on the characteristics of the solid acid catalysts was investigated. Catalysts prepared with a sequential carbonization method, pyro-hydrochar, exhibited the highest specific surface area while its sulfonated form showed good acidity of 2.14H+ mmol g−1. The catalytic performance of the prepared catalysts was evaluated through the esterification of acetic acid and ethanol. The catalyst derived from the sulfonated pyro-hydrochar presented higher catalytic activity than sulfonated pyrochar or hydrochar on its own. This study indicates that the sequential carbonization method is effective in producing carbonaceous material with great potential from U. pinnatifida that could be converted into highly efficient solid acid catalysts upon sulfonation.

Yeast-based biodiesel production using sulfonated carbon-based solid acid catalyst by an integrated biorefinery of durian peel waste

An integrated biorefinery concept for yeast-based biodiesel production using durian peel (DP) as a feedstock was developed. After dilute acid hydrolysis, DP hydrolysate (DPH) and DP solid fraction (DPSF) hydrolysis residues were generated. Yeast lipid was produced from undetoxified DPH by Rhodotorula mucilaginosa KKUSY14. DPSF was subjected to a one-step sulfonation process to prepare a solid catalyst (DPSF-SO3H) and was characterized using FTIR, XRD, and FE-SEM analysis. DPSF-SO3H catalyst exhibited good catalytic activity for yeast-based biodiesel (FAME) production from wet cell of KKUSY14 grown in DPH by direct transesterification. FAME yields of 81.57% and 78.73% were reached, respectively, for microwave and conventional heating. The fuel properties of FAME were in accordance with the ASTM and EN standards. Based on the higher heating value of FAME produced, an energy output of about 32.44–34.90 MJ/kg was estimated. The proposed bio-refinery concept led to the production of 101.2 kg yeast biomass, 16.0 kg yeast lipid, 717 kg DPSF-SO3H catalyst, 79.7–82.6 kg FAME, and 70.4 kg yeast residues from 1000 kg of DP waste. This model clearly provides economic benefits by creating value-added products and eliminating any waste streams.

Biodiesel synthesis by transesterification using coal-based solid acid catalyst

The medium metamorphic degree of bituminous coal with high oxygen content and low ash content is selected as the carbon carrier to prepare an efficient carbon-based solid acid catalyst through partial carbonization and sulfonation approach, and then is employed to catalyze transesterification of palm oil with methanol for biodiesel production. The strength of catalyst is characterized by Hammett inductor method. The reaction parameters are optimized by single factor method. Results demonstrate that the prepared catalyst possesses the Hammett acid strength range of 0.8<H0<3.3. The maximum biodiesel yield of 97.8% is obtained at catalyst dosage of 6 wt.%, transesterification temperature of 160 °C, molar ratio of methanol to palm oil of 18 and stirring rate of 1000 rpm for 8 h. Moreover, the catalyst exhibits satisfactory activity in catalyzing simultaneous esterification and transesterification when 20 wt.% oleic acid is added to palm oil.

Saccharification of cellulose using biomass-derived activated carbon-based solid acid catalysts

We prepared activated carbon-based solid acid catalysts derived from coconut shells via chemical activation with phosphoric acid under air and subsequent sulfonation. Their catalytic activities were evaluated in the saccharification of cellulose, and the parameters required for the activation and sulfonation processes were investigated. A catalyst activating temperature of 400 °C was found to be optimal, and the catalyst treated with chlorosulfuric acid exhibited a similar monosaccharide yield to that treated with fuming sulfuric acid. The prepared catalysts were characterized by various analytical techniques. The catalysts exhibited high specific surface areas and micropore volumes but low external specific surface areas. The catalysts had high contents of acidic functional groups when low activating temperatures were employed. For these catalysts, the surface chemical structure had a more dominant effect on the catalytic activity than that caused by the porous texture, while high acidic group contents led to high catalytic activities.

Potato peel waste-derived carbon-based solid acid for the esterification of oleic acid to biodiesel

Bio-waste valorization to generate carbon-based solid acid catalysts for biodiesel production from the low-grade, highly acidic feedstocks has been a research hot spot over the last decade. In this study, an abundant bio-waste from the household kitchens, restaurants, and food processing industries, potato peel (PP), was adopted as a raw material for the production of a solid acid catalyst (SO 3 H-PPAC). Firstly, PP was mixed with ZnCl 2 and activated at 450 °C for 1 h to obtain a porous carbon material (PPAC), which was subsequently sulfonated via concentrated sulfuric acid treatment. Various physicochemical techniques, such as XRD, N 2 physisorption measurements, FTIR spectroscopy, and high-resolution transmission electron microscopy (HR-TEM), were used to study the structural properties of the prepared materials. The catalytic behavior of the catalyst was tested in the acid-catalyzed esterification of oleic acid with methanol for biodiesel production. The combination of the high surface area of 827.7 m 2 / g and high concentration of acidic active sites of 1.6 mmol/g led to a high oleic acid conversion efficiency of 97.2% at 5 wt.% SO 3 H-PPAC, methanol/oleic acid molar ratio of 12:1 at 80 °C after 2.5 h. Moreover, the kinetic results unveiled that the esterification reaction obeyed the pseudo-first-order kinetic model, with an activation energy of 32.9 kJ/mol. Importantly, SO 3 H-PPAC has satisfying recyclable features and could maintain ∼ 70 % of its initial catalytic performance in the 5 th catalytic run. • Sulfonated carbon catalyst was synthesized from potato peel by ZnCl 2 activation and sulfonation. • The obtained catalyst exhibited high surface area of 827.7 m 2 g -1 . • Synthesized catalyst used in oleic esterification acid and afforded a high conversion of 97.2%. • The catalyst maintained ∼ 70 % of its initial catalytic performance in the 5 th catalytic run.

A novel magnetic carbon-based solid acid catalyst suitable for efficient hydrolysis of cellulose

A sucralose-derived magnetically separable carbon-based solid acid catalyst with cellulose-binding and catalytic sites has been successfully prepared by incompletely carbonizing the sulfonated sucralose with Fe3+ at high temperature to load ɤ-Fe2O3 nanoparticles onto the surface of the catalyst. The resultant magnetic catalyst was fully characterized and found to be suitable in the hydrolysis of cellulose. Microcrystalline cellulose pretreated by ball milling achieved the highest glucose yield of 32% using this neoteric catalyst at 363 K. Catalysts retained 90% of their activity after five runs recycle. The introduction of magnetic properties into the catalyst system will combine the high catalytic capacity for hydrolyzing cellulose and magnetic materials’ separation convenience.

Catalytic performance and deactivation mechanism of a one-step sulfonated carbon-based solid-acid catalyst in an esterification reaction

In this study, catalytic activity and deactivation mechanism of a carbon-based solid-acid catalyst in the esterification of oleic acid and methanol were investigated. The experimental results showed that the S150-4 catalyst, prepared by sulphonating at 150 °C for 4 h, yielded the highest sulfonic acid density. The conversion yield reached 97.98% under the optimum esterification conditions (i.e. catalyst loading, 10 wt%; methanol/oleic acid molar ratio, 8:1; reaction temperature, 65 °C; reaction time, 8 h) and decreased to 79.19% after four cycles. In the first batch of esterification, the formation of sulfonic esters was the main reason for the deactivation of the catalyst, whereas the leaching of sulphur was the main contributor in the second to fourth batches. Therefore, it is believed that reducing the leaching of sulphur and the formation of sulfonic esters by changing the addition method of methanol is an effective method to extend the service life of the catalyst.

Hydrolysis of corn stover pretreated by DESs with carbon-based solid acid catalyst

This study evaluated two hydrolysis strategies that involve a two-step and a one-pot process for the hydrolysis of cellulose. The two-step process consisted of cellulose pretreatment with deep eutectic solvent, followed by hydrolysis promoted by the carbon-based solid acid catalyst. The obtained results showed that the xylose and glucose yields were 33.9% and 6.9%, respectively, from corn stover based on this two-step strategy with ChCl ·Formic acid used as the pretreatment solvent. For one-pot hydrolysis, side reactions occurred and less glucose accumulated in the reaction system. In this case, the maximum achieved glucose yield was 21.1% for the hydrolysis of microcrystalline cellulose.Graphic abstractThe corn stover was pretreated with DES and then hydrolysed by carbon-based solid acid catalyst. Approximately 33.9% of xylose and 6.9% of glucose was recovered from corn stover with ChCl·Formic acid as the pretreatment solvent.

Synthesis of renewable heterogeneous acid catalyst from oil palm empty fruit bunch for glycerol-free biodiesel production

Interest in biodiesel research has escalated over the years due to dwindling fossil fuel reserves. The implementation of a carbon-based solid acid catalyst in biodiesel production eradicates the separation problems associated with homogeneous catalysis. However, its application in the glycerol-free interesterification process for biodiesel production is still rarely being studied in the literature. In this study, novel environmentally benign catalysts were prepared from oil palm empty fruit bunch (OPEFB) derived activated carbon (AC) which is sustainable and low cost via direct sulfonation using concentrated sulfuric acid. The effects of synthesizing variables such as carbonization and sulfonation temperatures with different holding times towards the fatty acid methyl ester (FAME) yield in interesterification reaction with oleic acid and methyl acetate were investigated in detail. It was found that the optimum carbonization temperature and duration together with sulfonation temperature and duration were 600 °C, 3 h, 100 °C and 6 h, respectively. The catalyst possessed an amorphous structure with a high total acid density of 9.0 mmol NaOH g−1 due to the well-developed porous framework structure of the carbon support. Under these optimum conditions, the OPEFB derived solid acid catalyst recorded an excellent catalytic activity of 50.5% methyl oleate yield at 100 °C after 8 h with 50:1 methyl acetate to oleic acid molar ratio and 10 wt% catalyst dosage. The heterogeneous acid catalyst derived from OPEFB had shown promising properties that made them highly suitable for cost-effective and environmental-friendly glycerol-free biodiesel production.

ADVANCES IN BIODIESEL SYNTHESIS: THE ROLE OF VARIOUS CATALYSTS

Biodiesel is a renewable, clean-burning, and biodegradable fuel which can be synthesized from readily available domestic and natural sources, such as edible, non-edible and waste cooking oils, which may serve as a substitute to petro-diesel. It is produced by catalytic transesterification of fats and oils. A number of researches has been devoted to discovering a benign catalyst, especially heterogeneous acid catalyst that could convert non-edible and waste cooking oils with high free fatty acid into biodiesel, in an attempt to reduce the cost of production. The cost of production of biodiesel is still far higher than that of conventional petro-diesel, owing to the cost of edible oil currently being used, processes involved, and cost of conventional heterogeneous catalysts employed. This study assessed the role of various catalysts; homogeneous, heterogenous and enzyme-catalyzed transesterification reactions, in terms of their advantages and disadvantages in biodiesel production in order to establish very promising catalysts. Some methods of heterogeneous acid catalysts were also highlighted. Amongst the common heterogeneous catalyst, carbon-based solid acid catalysts were recommended as very promising solid acid catalyst that can utilize the non-edible oils in biodiesel production. The advantages of carbon-based solid acid catalysts include cheap readily available raw materials for their synthesis, easier production processes, relative stability, high reusability and potential for utilizing waste and non-edible oils for biodiesel production. &#x0D; Nnaji, J. C. | Department of Chemistry, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria

Preparation of Carbon-Based Solid Acid Catalysts Using Rice Straw Biomass and Their Application in Hydration of α-Pinene

Carbon-based solid acid catalysts were prepared using rice straw (RS) waste, and the effects of carbonization temperature and sulfonation temperature on the catalytic activity were investigated. The properties of the catalysts were characterized using thermo gravimetric (TG), scanning electron microscope (SEM), Brunauer–Emmet–Teller (BET), Fourier transform infrared spectroscopy (FT-IR), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS), and their activities were investigated through the hydration of α-pinene. The conversion of α-pinene and the selectivity of α-terpineol reached 67.60% and 57.07% at 80 °C and atmospheric pressure in 24 h, respectively. The high catalytic capacity of the catalyst is attributed to the high acid site density and high porosity of the catalyst. TPD analysis and FT-IR spectroscopy showed that the catalyst produced by low-temperature carbonization at 300 °C followed by low-temperature sulfonation at 80 °C had abundant strong acid sites (0.82 mmol/g), which can effectively inhibit the side reactions of hydrated α-pinene. The total acidity reached 2.87 mmol/g. N2-physisorption analysis clearly indicated that the obtained catalysts were mesopore-predominant materials, and the SBET and VTotal of catalysts reached 420.9 m2/g and 4.048 cm3/g, respectively. Preparation of the catalyst involves low energy consumption, and its cheap raw materials make the whole process simple, economical, and environmentally friendly.

Carbon-Based Catalysts for Biodiesel Production—A Review

In recent years, a new class of superior heterogeneous acid catalyst for biodiesel production has emerged. These catalysts offer advantages over their predecessors such as high surface area, elevated acid site density, enhanced catalyst activity, good operation stability and relevant economic affordability in an environmentally friendly frame. This review was concerned with carbon-based solid acid (CBAS) catalysts derived from both carbohydrate and pyrolysis products. A series of CBASs with various origins such as D-glucose, sucrose, starch, cellulose and vegetable oil asphalt, converted to char and sulphonated, have been explored as potential heterogeneous catalysts. Catalyst preparation and synthesis methods were briefly summarized. Catalyst characterization and performance for biofuels related reactions were elucidated, identifying potential research applications. Three catalysts in particular were identified as having potential for industrial application and requiring further research.

Highly Efficient Conversion of Xylose to Furfural in a Water–MIBK System Catalyzed by Magnetic Carbon-Based Solid Acid

In this work, the conversion of xylose to furfural (FF) was effectively achieved in a water–MIBK biphasic solvent system over a synthesized magnetic carbon-based solid acid catalyst (MMCSA). The ef...

Production of furfural from xylose catalyzed by a novel calcium gluconate derived carbon solid acid in 1,4-dioxane

A novel carbon-based solid acid catalyst (SC-GCa-800) was prepared by the high-temperature carbonization of calcium gluconate followed by sulfonation with 4-diazoniobenzenesulfonate at room temperature.

Novel Carbon-based Solid Acid from Green Pistachio Peel as an Efficient Catalyst for the Chemoselective Acylation, Acetalization and Thioacetalization of Aldehydes, Synthesis of Biscoumarins and Antimicrobial Evaluation

Background: Much attention has been focused on heterogeneous catalysts. Reactions with these recoverable and reusable catalysts are clean, selective with high efficiency. Among the heterogeneous solid acid catalyst in organic synthesis, Carbon-Based Solid Acids (CBSAs), which are important solid acid with many practical and research applications have been extensively studied. In this work, green Pistachio peel, a biomass waste, was converted into a novel carbon-based solid acid catalyst (Pis-SO3H). Objective: The aim of this work is to synthesize highly sulfonated carbon as an efficient, recyclable, nontoxic solid acid catalyst by simultaneous sulfonation, dehydration and carbonization of green Pistachio peel as biomass and investigate the catalytic activity of Pis-SO3H in acetalization, thioacetalization, acylation of aldehydes and synthesis of 3,3'-Arylmethylene-bis(4-hydroxycoumarin) derivatives. Method: Pis-SO3H was synthesized by an integrated fast one-step hydrothermal carbonization and sulfonation process in the presence of sulfuric acid. The characterization of the physicochemical properties of Pis-SO3H was achieved by XRD, FT-IR, FE-SEM, and elemental analysis. Results: The result of acid-base titration showed that the total acidity of the catalyst was 7.75 mmol H+g−1. This new heterogeneous catalyst has been efficiently used for the chemoselective thioacetalization, acetalization and acylation of aldehyde and the synthesis of biscoumarins under solvent-free conditions. All the reactions work easily in high yields. The antimicrobial activity of some of the biscoumarins was evaluated in screening by disk diffusion assay for the zone of inhibition. Conclusion: The catalytic activity of the Pis-SO3H was investigated during acetalization, thioacetalization, acylation and synthesis of biscoumarins. The results of protection of carbonyl groups and synthesis of biscoumarins in the present work offer effective alternatives for environmentally friendly utilization of abundant biomass waste.

Catalytic activity of heterogeneous acid catalysts derived from corncob in the esterification of oleic acid with methanol

Sulfuric acid (H2SO4) pretreated corncob-derived residue was used as a starting material to prepare solid acid catalysts using different sulfonation chemicals (H2SO4, p-toluenesulfonic acid (TsOH) and H2SO4/TsOH mixtures) for biodiesel production from the esterification of oleic acid with methanol. Effects of the different sulfonation agents on the properties of the derived carbon-based materials were investigated using various characterization techniques. Lignin residues were obtained after the H2SO4 pretreatment step, and high lignin-containing carbon-based catalysts of ca. 69% (w/w) lignin were derived after sulfonation with H2SO4. Employing TsOH or H2SO4/TsOH mixtures for sulfonation gave materials with a higher carbon/hydrogen (C/H) ratio, indicating a relatively effective carbonization compared to that with H2SO4 sulfonation. The catalytic activity of the sulfonated corncob in the esterification of oleic acid with methanol was influenced by the acid density, acid strength and porous structure of the sulfonated materials. High methyl oleate yields (>80% after 8 h at 60 °C) were achieved using the acid catalyst obtained from either H2SO4 or TsOH sulfonation, whereas those from H2SO4/TsOH sulfonation gave slightly lower yields. Thus, the use of the non-volatile TsOH solid as a ‘greener’ sulfonating agent for the production of carbon-based solid acid catalysts with a high catalytic activity in the esterification reaction is supported.