Carbon-based Solid Acid Catalyst Research Articles

Efficient conversion of xylose and corncob to furfural using a novel carbon-based solid acid derived from black liquor lignin-tin complexes

The novel carbon-based solid acid catalyst was prepared by carbonizing the mixture of metal salts and black liquor, followed by sulfonating. The physicochemical properties of the catalysts were characterized by SEM, FTIR, BET, NH3-TPD, Py-IR, XPS, ICP, and elemental analysis. The catalytic ability of the catalyst was explored by converting xylose and corncob to furfural via a one-step process. The effects of solvent types and water contents, catalyst dosage, substrate concentration, reaction temperature, and reaction time on furfural yield were evaluated. 93.4 % of furfural yield was achieved using 200 mg xylose at 170 °C for 120 min with 150 mg catalysts. Moreover, the furfural yields of 82.5 % were obtained from corncob. This work provides a promising strategy for synthesizing carbon-based solid acid catalysts from pulp waste black-liquid resources, which has a potential application for producing furfural from hemicellulose.

Formulation of a carbon-based solid acid catalyst from groundnut husk for the esterification of oleic acid

In this research, a biochar was prepared from groundnut husk and sulphuric acid. The biochar wassulphonated with chlorosulphonic acid to give a carbon-based sulphonated solid acid catalyst (SAC). The catalyst was characterised by N2 adsorption and desorption at 77K after degassing overnight under vacuum at 250˚ C, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and total acid density measurement. The results of the acid density measurement showed that the sulphonated biochar has a relatively high acid density of 3.2 mmol/g, while that of the non-sulphonated counterpart is 0.56 mmol/g. Comparison of the percentage conversion of oleic acid by esterification with methanol and butanol was carried out under three different conditions, viz: without catalyst, with the non-sulphonated biochar and with the sulphonated biochar, under the same experimental conditions of 5% catalyst weight percent (based on weight of acid), acid-methanol mole ratio of 1:12, reaction temperature of 70 oC, and five hours reaction time. Up to 91.6% percentage conversion of oleic acid to methyl oleate and 86.4% for butyl oleate were achieved, proving the effectiveness of the sulphonated biochar in catalysing the esterification reaction of oleic acid with methanol and butanol. The results of this study are expected to provide insights into the development of sustainable and cost-effective solid acid catalysts for the synthesis of oleate esters and other value-added materials from renewable feedstocks.

Preparation of carbon-based solid acid catalyst from rice straw for furfural production in aqueous media

Preparation of carbon-based solid acid catalyst from rice straw for furfural production in aqueous media

One-Pot Effective Approach to 2,5-Diformylfuran From Carbohydrates Using MoS2-Decorated Carbonaceous Sugarcane Bagasse.

Exploring the transformation of carbohydrates into valuable chemicals offers a promising and eco-friendly method for utilizing renewable biomass resources. Developing a bi-functional, sustainable heterogeneous catalyst is of utmost importance to attain a high level of selectivity for the desired product, 2,5-diformylfuran (DFF), in this direct conversion process. In this study, we developed a highly effective catalytic system to convert diverse carbohydrates into DFF. Our approach involved utilizing a MoS2 catalyst supported by amorphous carbon derived from sulfonated sugarcane biomass. The MoS2@SBG-SO3H composite was successfully synthesized using a facile and highly efficient method. The transformation of fructose into DFF achieved a significant yield of 70 % for 5 h at 160 °C using a one-step and one-pot reaction through dehydration and oxidation with oxygen. The oxidation of 5-hydroxymethylfurfural (HMF) into DFF using MoS2@SBG-SO3H was obtained at 94 % DFF within 5 h; the activation energy was 38.3 kJ . mol-1. The catalyst displayed convenient recovery and reusability. The direct synthesis of DFF from various carbohydrates, such as sucrose, glucose, maltose, and lactose, resulted in favorable yields. Our research provides a quick, green, and efficient process for preparing carbon-based solid acid catalysts and DFF.

Enhanced cellobiose hydrolysis over fluorine-modulated carbon-based solid acid catalysts

In this study, we synthesized novel carbon-based solid acid catalysts using plasma engineering by integrating sulfonic acid groups as primary catalytic sites and supplemented these with fluorine-containing, chlorine-containing, and other oxygenated functional groups (OFGs). Notably, the catalyst with the fluorine-containing functional groups results superior glucose yield (58.2 %) than that containing only OFGs (37.6 %). Theoretical analysis of the reaction energetics revealed that the cleavage of cellobiose's 1,4-O linkage to form two glucose molecules potentially constitutes the rate-determining step (RDS) in cellobiose hydrolysis. The reaction energy for this RDS was found to increase in the sequence of G–SO3H–F, G–SO3H–Cl, and G-SO3H, consistent with the experimentally obtained catalytic activity trends. Through extensive characterization, including textural analysis, surface chemistry, and density functional theory calculations, we identified that the –F groups are the key to strengthening cellulose–catalyst interactions. This study is the first study to demonstrate the potential of fluorine-modulated carbon-based solid acid catalysts for upgrading cellulosic biomass to value-added compounds.

A solid acid derived from fishbone catalyzes the hydrolysis of cellulose into nanocellulose

The necessity to look into waste biomass resource regeneration has increased due to growing environmental and energy-related problems. This study successfully developed an innovative fishbone-derived carbon-based solid acid catalyst using the carbonation-sulfonation method, which was subsequently applied to catalyze the hydrolysis of cellulose to produce nanocellulose. The data analysis reveals that the sulfonation treatment affects the microstructure of the catalyst, resulting in a decline in its specific surface area (134.48 m2/g decreased to 9.66 m2/g). However, this treatment doesn't hinder the introduction of acidic functional groups. In particular, the solid acid catalyst derived from fishbone exhibited a total acid content of 3.76 mmol/g, with a concentration of -SO3H groups at 0.48 mmol/g. Furthermore, the solid acids originating from fishbones manifested remarkable thermal stability, exhibiting a mass loss of <15 % at temperatures up to 600 °C. Moreover, the catalyst displayed exceptional catalytic performance during the cellulose hydrolysis reaction, achieving an optimum nanocellulose yield of 45.7 % at an optimized reaction condition. An additional noteworthy feature is the solid acid catalyst's impressive recyclability, maintaining a nanocellulose yield of 44.87 % even after undergoing five consecutive usage cycles. This research outcome underscores an innovative approach to for the sustainable utilization of waste biomass resources.

Sulfonated P-W modified nitrogen-containing carbon-based solid acid catalysts for one-pot conversion of cellulose to ethyl levulinate under water-ethanol medium

Sulfonated P-W modified nitrogen-containing carbon-based solid acid catalysts for one-pot conversion of cellulose to ethyl levulinate under water-ethanol medium

Efficient and selective conversion of xylose to furfural over carbon-based solid acid catalyst in water-γ-valerolactone

Hydrothermal liquefication of biomass to produce high-quality chemicals and liquid fuels is considered as a renewable and sustainable technology. Herein, a one-step hydrothermal method was used to prepare microcrystalline cellulose supported carbon-based catalyst PTA-BC with the activation factor of phosphotungstic acid. It was demonstrated by Py-FTIR, NH3-TPD and XPS that PTA-BC is not only rich in functional groups but also contains Brønsted acid sites (hydroxyl groups) and Lewis acid sites (CC, carboxyl groups). After experimental optimization, the optimum yield of furfural obtained from xylose catalyzed by PTA-BC was 81.02% at the reaction temperature of 180 °C and the reaction time of 20 min. The results show that PTA-BC contains –COOH, –OH and CC as catalytic sites and that the synergistic effect of these functional groups. The nature of the reaction solvent, appropriate reaction temperature and residence time are the main reasons for the good catalytic performance. This work provides a promising way for the synthesis of solid acid catalyst, which has a wide application prospect for the production of furfural.

Influence of Brönsted Acid Sites on Activated Carbon-Based Catalyst for Acetylene Dimerization.

Activated carbon (AC) has been widely used as a support material with both tunable acidity and abundant functional groups for solid acid catalysts in various chemical processes such as acetylene dimerization. A facile, mild acid modification method that directly activates AC to generate rich defects and oxygen functional group surface structures with Brönsted acid sites and an enhanced conductivity is presented here. Impressively, the catalyst with optimized Brönsted acid sites and an enhanced dispersion of active components exhibited a superior acetylene dimerization catalytic activity. Moreover, theoretical calculations indicated that an increase in hydrogen concentration could inhibit the formation of coke. This research offered a feasible potential way to devise and construct a carbon-based solid acid catalyst with an excellent catalytic performance.

The cellulose hydrolysis into glucose with carbon-based solid acid catalyst via machine learning, life cycle assessment and bibliometric analysis

The cellulose hydrolysis into glucose with carbon-based solid acid catalyst contributes to sustainable and low-carbon development. Determining the quantitative impact of key variables on glucose yield and environmental sustainability is a notoriously time-consuming and labor-intensive process. In this study, a bibliometric analysis was carried out to examine the current research on cellulose hydrolysis into glucose using solid acid catalyst. The application of machine learning (ML) has demonstrated that the random forest (RF) model possesses optimal predictive performance concerning the glucose yield (Training R2 = 0.89, Testing R2 = 0.80, MAE = 6.52, RMSE = 8.29). The SO3H acid densities was emerged as a most crucial influential parameter. The interactions relationship of influenced factors for glucose production was clarified by the partial dependence plot analysis (PDPs). Furthermore, the life cycle assessment (LCA) further indicated that the carbon solid acid catalysts used in cellulose hydrolysis to produce glucose have lower emissions of CO2, NOx, and SO2 compared to traditional acid catalysts, which is 85.5 kg ep of CO2, 0.17 kg ep of NOx, 0.23 kg ep of SO2 for carbon solid acid catalysts, while 91.84 kg ep of CO2, 0.24 kg ep of NOx, 0.61 kg ep of SO2 emission for acid hydrolysis. Thus, carbon solid acid catalysts have a comparably lower negative environmental impact than traditional acid hydrolysis. This study provides crucial insights into improving the prediction accuracy of ML models and reducing the carbon footprint involved in glucose production.

Lignin-derived carbon-based solid acid catalyst for the conversion of Pueraria cellulose to lactic acid

Lignin-derived carbon-based solid acid catalyst for the conversion of Pueraria cellulose to lactic acid

Cellulose hydrolysis reactor incorporating stirring apparatus for use with carbon-based solid acid catalyst

A highly efficient reactor with a stirring device was specially designed with the intent of performing the hydrolysis of pure crystalline cellulose using a carbon-based solid acid catalyst. This catalyst comprised an amorphous carbon-based material bearing –SO3H, –COOH and –OH groups. The stirring apparatus had seven blades coated with polytetrafluoroethylene and arranged axially at regular intervals with a 60° offset. This design proved highly effective, providing double the glucose yield compared with conventional stirring systems. The basic properties of this novel reactor were investigated and analyzed and are discussed herein.

Structure and Catalytic Performance of Carbon-Based Solid Acids from Biomass Activated by ZnCl2

In the current investigation, carbon-based solid acid catalysts were synthesized from peanut shells (PSs) and rice straw (RS) using ZnCl2 activation and concentrated sulfuric acid sulfonation. These catalysts were then employed for the hydration of pinene to produce terpineol. The research findings suggest that the natural porous structure of RS is more amenable to ZnCl2 activation compared to PSs. Furthermore, the catalysts prepared from fully activated RS by ZnCl2 (RSA-C-S) had a higher SBET and higher density of oxygen-containing groups (–COOH) in comparison with unactivated RS-based solid acids (RSC-S). The characterization outcomes revealed that RSA-C-S possesses a specific surface area of 527.0 m2/g, significantly outperforming RSC-S, which has a surface area of 420.9 m2/g. Additionally, RSA-C-S registered a higher –COOH density of 1.37 mmol/g, as opposed to RSC-S’s, with 1.07 mmol/g, attributable to the partial oxidation of internal –OH groups during activation. Experimental data from hydration tests confirmed that the catalyst’s superior performance is largely attributed to its elevated specific surface area and a high density of –COOH functional groups. Under optimal reaction parameters, RSA-C-S demonstrated unparalleled catalytic efficiency in the synthesis of α-terpineol via hydration of α-pinene, achieving conversion and selectivity rates of 87.15% and 54.19%, respectively.

A novel carbon-based solid acid catalyst with high acidity for the hydration of α-pinene to α-terpineol: Effect of graphite crystallite size and synergistic effect of defects

This work, for the first time, highlights that small-sized graphite crystallite and highly defective carbon-based catalysts can effectively increase the −SO3H density of the catalysts and modulate the surface electronic properties of the catalysts, which further facilitates the α-pinene hydration reaction. Hydrothermal phosphoric acid modulation of graphite crystallite size and defects in carbon-based catalysts systematically revealed the correlation between −SO3H density, catalytic activity, graphite crystallite size, and defects in biomass carbon. The characterization results demonstrate that small-size graphite crystallites and high structural defects provide more sp2 hybridized carbon edges, contributing to the catalyst's increase of −SO3H density. The −SO3H group density of the catalyst increased from 0.89 to 1.20 mmol/g after hydrothermal phosphoric acid treatment. The catalyst has the highest efficiency in the α-pinene hydration to α-terpineol among the reported catalysts, in which 87.06 % of α-pinene was converted and reached a maximum α-terpineol selectivity (55.38 %) time only 22 h. Density functional theory calculations show that the lattice defects of graphite crystallites in catalysts lead to the polarization of the electron cloud around the catalyst, which further leads to the reduction of electrostatic resistance between α-pinene and the active catalytic sites. The apparent activation energy of hydration by the catalyst is 1.74 times lower than that of conventional biomass carbon-based solid acids. The reduction of graphite crystallite size is considered a critical step in improving the selectivity of α-terpineol attributed to the effective reduction of α-terpineol adsorbed on the catalyst.

Powder properties of carbon-based solid acid catalyst for designing cellulose hydrolysis reactor with stirring apparatus

The powder properties of a carbon-based solid acid catalyst, an amorphous carbon material bearing SO3H, COOH and OH groups, were investigated for the hydrolysis of cellulose. The Carr flowability and floodability indices, the angle of internal friction (adherence), and the particle size distribution and shape for the powder catalyst were determined. The need to develop a special reactor with a stirring apparatus for the hydrolysis of cellulose was determined based on the Carr flowability index. Insight into the interaction or adherence between the catalyst and crystalline cellulose during the hydrolysis process was gained by measuring the internal friction angle. The optimum moisture content in the catalyst to achieve the maximum adherence was investigated.

H2SO4 assisted hydrothermal conversion of biomass with solid acid catalysis to produce aviation fuel precursors

With hydrothermal reaction, lignocellulosic biomass can be efficiently converted into furfural (FF) and levulinic acid (LA), both of which are key platform compounds that can be used for the subsequent preparation of aviation fuels. In order to reduce the acid concentration in traditional hydrolysis and provide a reaction system with good catalytic activity, we propose a biomass conversion route as dilute acid hydrolysis coupled with solid acid catalysis. Firstly, at different temperatures, the hemicellulose and cellulose in corn stover were step-hydrolyzed by sulfuric acid solution with a concentration of 0.9 wt.% to produce xylose and glucose, with conversion reaching 100% and 97.3%, respectively. Subsequently, a new resin-derived carbon-based solid acid catalyst was used to catalyze the aforementioned saccharide solutions to obtain FF with yield of 68.7 mol% and LA of 70.3 mol%, respectively. This work provides a promising approach for the efficient production of bio-aviation fuel precursors.

Preparation of Carbon-Based Solid Acid Catalyst from High-Sulfur Petroleum Coke with Nitric Acid and Ball Milling, and a Computational Evaluation of Inherent Sulfur Conversion Pathways.

A series of petroleum coke (petcoke)-derived solid acid catalysts were prepared via nitric acid treatment with or without ball milling pretreatment. The inherent sulfur in petcoke was converted to sulfonic groups, which were active sites for the esterification of octanoic acid and methanol at 60 °C, with ester yields of 14-43%. More specifically, samples without ball milling treated at 120 °C for 3 h had a total acidity of 4.67 mmol/g, which was 1.6 times that of the samples treated at 80 °C, despite their -SO3H acidities being similar (~0.08 mmol/g). The samples treated for 24 h had higher -SO3H (0.10 mmol/g) and total acidity (5.25 mmol/g) but not increased catalytic activity. Ball milling increased the defects and exposed aromatic hydrogen groups on petcoke, which facilitated further acid oxidation (0.12 mmol -SO3H/g for both materials and total acidity of 5.18 mmol/g and 5.01 mmol/g for BP-N-3/120 and BP-N-8/90, respectively) and an increased ester yield. DFT calculations were used to analyze the pathways of sulfonic acid group formation, and the reaction pathway with NO2• was the most thermodynamically and kinetically favourable. The activities of the prepared catalysts were related to the number of -SO3H acid sites, the total acidity, and the oxygen content, with the latter two factors having a negative impact.

A remarkable bifunctional carbon-based solid acid catalyst derived from waste bio-tar for efficient synthesis of 5-hydroxymethylfurfural from glucose

A remarkable bifunctional carbon-based solid acid catalyst derived from waste bio-tar for efficient synthesis of 5-hydroxymethylfurfural from glucose

Development of sulfonated carbon-based solid-acid catalysts derived from biorefinery residues and biomass ash for xylan hydrolysis

In this study, biorefinery residues and biomass ash were used to develop sulfonated carbon-based solid-acid catalysts to enhance xylan hydrolysis. Metals extracted from the biomass ash were impregnated into a carbon support prepared from biorefinery residues to synthesize sulfonated ash-impregnated carbon-based catalyst. Metals present in the ash most probably are responsible for the increased acid density in the catalyst. Using this catalyst, 11.4 % xylose yield was produced, an increase of 171 % over the yield obtained from a catalyst without ash impregnation. Using a xylan-to-catalyst ratio of 1:2, 72.9 % xylose yield was obtained, comparable to using 0.5 wt% sulfuric acid under the same reaction condition. Moreover, this catalyst significantly inhibited xylose dehydration, only forming 11.3 % furfural compared to that generated using dilute acid. Hence, these results show the potential for using biomass ash as a metal source to increase the number of acid sites in solid-acid catalysts used for biomass pretreatment.

Valorization of lignocellulosic wastes for low-cost and sustainable algal biodiesel production using biochar-based solid acid catalyst

Recently, carbon-based solid acid catalysts have come into prominence among different types of catalyst for production of biodiesel. Solid acid catalysts can be produced from carbon based materials such as biomass wastes by reducing the cost. Utilization of these wastes to prepare solid acid catalyst provides solid waste management and the potential greenhouse gas emissions decreases. Since algal biodiesel production is not so economical and needs to be improve, using these catalysts produced from waste biomass can be promising for making the process more cost effective and a low cost applicable zero-waste biorefinery approach can be put forth. In this study, walnut shell, olive stone and macroalgae were utilized to produce biochar based solid acid catalyst to be evaluated in microalgal biodiesel production. Walnut shell carbonized at 500 °C and then sulfonated by sulfuric acid was selected for biodiesel production due to having higher sulfonic acid density (0.35 mmol/g) and preferable structural properties. The statistical evaluation of transesterification parameters effect on microalgal biodiesel yield were evaluated and yield of 82% was found as the highest which was obtained by using 5 wt% catalyst, 12:1 methanol/oil molar ratio at the reaction time of 60 min. Stability test also showed the catalyst can be re-used up until the 5th cycle. Low cost feedstock and reusability of the catalyst presented a simple, cost-effective and environment-friendly process. At last, lignocellulosic wastes can be suggested for not only as biochar production also can be evaluated as solid acid catalyst and provide a cost-efficient biodiesel production.