Carbon-based Solid Acid Research Articles

Preparation and characterization of biomass carbon-based solid acid catalyst for the esterification of oleic acid with methanol

A solid acid catalyst, prepared by sulfonating carbonized corn straw, was proved to be an efficient and environmental benign catalyst for the esterification of oleic acid and methanol. Various synthetic parameters, such as carbonization temperature and time were systematically examined. It was found that the catalyst exhibited the highest acid density of 2.64mmol/g by NaOH titration. A quantitative yield (98%) of ester was achieved, using the most active sulfonated catalyst at 333K with a 7wt.% catalyst/oleic acid ratio for 4h, at a 7:1M ratio of methanol/oleic acid, while the commercial available Amberlyst-15 only gave 85% yield under the same reaction condition.

Carbon-based solid acid: an efficient and reusable catalyst for the diastereoselective ring opening reaction of α-epoxyketones

Carbon-based solid acid efficiently catalyzes diastereoselective ring opening of α-epoxyketones in the presence of methanol to produce the corresponding α-hydroxy-β-methoxyketones in excellent yield.

Coaled Carbon-Based Solid Acid: a New and Efficient Catalyst for Click Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones under Solvent-Free Conditions

Coaled carbon-based solid acid (CCBSAC) is reported as a new, efficient and recyclable catalyst for the regioselective multicomponent synthesis of dihydropyrimidin-2(1H)-ones from aldehydes, β-ketoesters and urea or thiourea under solvent-free conditions. The structure and thermal stability of CCBSAC which resulted from ultra-clean coal resources mainly were characterized by IR, XRD, and TG. Nineteen dihydropyrimidin-2(1H)-ones examples were prepared and this catalyst could recycle up to 4 consecutive runs without losing its efficiency. The high yields of products, short reaction times, ease of work-up and clean procedure will make the present method a useful and important addition to the previous methodologies for the synthesis of dihydropyrimidin-2(1H)-ones.

Soft-template synthesis of sulfonated mesoporous carbon with high catalytic activity for biodiesel production

Here, we reported an excellent carbon-based solid acid catalyst for the catalytic synthesis of biodiesel, which was prepared by carbonizing a mesoporous phenolic resin and then followed by sulfonation with concentrated sulfuric acid. The influence of carbonization temperature on the pore structure and acidity was studied. Fourier transform infrared spectroscopy, energy dispersive spectrum analysis and an indirect titration method were used to demonstrate the successful modification of –SO3H groups on the carbon surface and determine the acidities of catalysts. N2 adsorption–desorption and transmission electron microscopy were used to characterize the mesoporous structure and pore structure parameters. These results indicated that the sulfonated catalyst carbonized at a low temperature (400 °C) showed the highest acidity of 2.21 mmol H+ g−1, meanwhile, retaining a mesoporous structure and relatively large surface area. The esterification reaction of oleic acid with methanol was employed to evaluate the performance of catalysts. The sulfonated mesoporous carbon catalyst exhibited a highly efficient activity, above 95% conversion of oleic acid with a 30 : 1 methanol/oleic acid at 70 °C for 3 h. Experimental parameters, including the molar ratio of reactants, reaction time and reaction temperature, were optimized and a superior recycling property was presented after five consecutive cycles.

Preparation and catalytic performance of a carbon-based solid acid catalyst with high specific surface area

A carbon-based solid acid catalyst was prepared by incomplete carbonization of H3PO4-impregnated pulp fibers followed by sulfonation. XRD, FT-IR, BET, TGA, and acid density test were employed to characterize the structure and performance of the catalyst. Results showed that the catalyst was amorphous carbon composed of aromatic carbon sheets with –COOH, –OH and –SO3H groups. Previous impregnation with H3PO4 could promote porosity formation of the catalyst. The optimized carbonization temperature and time for the catalyst were 250 °C and 1.5 h. The –SO3H density and specific surface area for the catalyst prepared under the optimized conditions were 1.1 mmol g−1 and 118 m2 g−1, respectively. Compared to HZSM-5, Amberlyst-15 and previous reported carbon catalysts, the catalyst showed higher catalytic activity for transesterification of methyl acetate with n-butanol as hydrophobic reaction. The catalyst had good thermal stability, which could bear 200 °C without decomposition. The catalyst retained satisfactory catalytic activity for transesterification of methyl acetate after 8 reaction cycles.

Preparation of a Novel Carbon Based Solid Acid Catalyst for Biodiesel Production via a Sustainable Route

A novel carbon-based solid acid catalyst has been synthesized via a sustainable route, by using glycerol, a byproduct in biodiesel production, as a precursor. The newly obtained catalyst is glycerol-derived and amorphous with irregular morphology and mesoporous structure. For both biodiesel production and glycerol utilization, it demonstrates as promising. Compared with amberlyst-15, the commonly used one, the new catalyst has shown highly catalytic activity and recycling performance in esterification of oleic acid and transesterification of triolein. The highly catalytic activity of the catalyst for biodiesel production can be mainly attributed to the high density of acidic –SO3H groups and hydrophilic groups on its surface.

Liquid-phase dehydration of 1-phenylethanol to styrene over sulfonated D-glucose catalyst

Dehydration of 1-phenylethanol to produce styrene has been studied in liquid phase without any solvent with carbon-based solid acid catalysts prepared in one step from renewable resources like d-glucose for the first time. The carbon-based catalyst shows higher styrene selectivity and lower activation energy than other solid acid catalysts that have been used so far, demonstrating that a carbon-based catalyst is very effective in producing styrene from 1-phenylethanol.

CARBON-BASED SOLID ACID CATALYZED SYNTHESIS OF POLYHYDROQUINOLINE DERIVATIVES VIA HANTZSCH REACTION UNDER SOLVENT-FREE CONDITIONS

An easy method for the synthesis of polyhydroquinoline derivatives via one-pot four-component Hantzsch condensation of dimedone, aryl aldehydes, ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of carbon-based solid acid (CBSA) in solvent-free conditions is described. The main advantages of the present approach are relatively short reaction times, high product yields, clean reaction profiles, simple experimental and work-up procedure.

Carbon-Based Solid Acid as an Efficient and Reusable Catalyst for the Synthesis of 1,8-Dioxodecahydroacridines Under Solvent-Free Conditions

Carbon-based solid acid catalyst was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the multicomponent reaction of dimedone, aromatic aldehydes, and a nitrogen source (ammonium acetate or aromatic amines) under solvent-free conditions, giving rise to 1,8-dioxodecahydroacridines in high yields. The present methodology offers several advantages, such as a simple procedure with an easy work-up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents.

Carbon-based solid acid catalyst from de-oiled canola meal for biodiesel production

Abstract A carbon-based acid catalyst was prepared by the sulfonation of partially carbonized de-oiled canola meal (DOCM), a by-product of canola seed processing. Partial carbonization of DOCM was carried out at 300 and 400 °C and the partially carbonized material prepared at 400 °C was steam activated to improve its surface properties. Four types of carbon catalysts were prepared using the partially carbonized material and DOCM by concentrated sulfuric acid treatment. The spectral and elemental analysis clearly indicated that the catalyst had enough acidic sites in the form of sulfonate groups having the ability to promote esterification reaction. The catalyst partially carbonized at 300 °C established various functional groups such as aromatic carbon atoms, phenolic-OH, COOH, and carbonyl groups on the surface as evidenced by the MAS 13C NMR and FTIR spectra. The catalyst produced by partial carbonization at 300 °C followed by sulfuric acid treatment showed better performance towards esterification of oleic acid and high FFA canola oil. The maximum conversion reached 93.8% after 24 h at 65 °C using 1:60 mol:mol of FFA to methanol and 7.5 wt.% of catalyst to FFA. The performance of the catalyst was reduced gradually during its recycling and reached to 40.5% at the end of 4th cycle.

Hydrolysis of carboxylic acid esters catalyzed by a carbon-based solid acid

A carbon-based solid acid catalyst is prepared by incomplete carbonization of sulfonated naphthalene and used for the hydrolysis of carboxylic acid esters. XRD, FT-IR, TGA and acid density test are employed to characterize the structure and performance of the catalysts. The results show that the catalysts prepared under different synthesis temperature and time are amorphous carbon composed of small aromatic carbon sheets with –SO3H groups. The catalytic activities of catalysts for methyl acetate hydrolysis are closely related with their acid densities. The appropriate synthesis temperature and time for the catalyst are 230 °C and 12 h and the acid density of catalyst under the optimized conditions can reach 4.49 mmol g−1. The carbon-based solid acid shows higher catalytic activity than Amberlyst-15 resin as a popular hydrolysis catalyst for a series of carboxylic acid esters hydrolysis. The catalyst has good thermal stability, which can bear 250 °C without decomposition. It also remains satisfactory catalytic activity for methyl acetate hydrolysis after six times recycling.

Efficient carbon-based solid acid catalysts for the esterification of oleic acid

Abstract A series of carbon-based solid acid catalysts was prepared by the sulfonation of mesoporous carbon substrates with thin pore walls, and catalytic activity for the esterification of oleic acid with methanol was tested. The highest turnover frequency (TOF) observed was 78 h − 1 , five times that of Amberlyst-15. The high catalytic activity may be attributed to the good dispersion of the catalysts in methanol. Catalysts with improved dispersion were obtained by a modified preparation, after which the highest TOF observed was 109 h − 1 , seven times that of Amberlyst-15.

Structure and Catalysis of Cellulose‐Derived Amorphous Carbon Bearing SO3H Groups

The correlation between catalytic performance and structure of a cellulose-derived and carbon-based solid acid (CCSA), an amorphous carbon bearing SO(3)H, COOH, and phenolic OH groups, was investigated. Sulfonation of partially carbonized cellulose under a N(2) atmosphere resulted in the formation of a CCSA, which was amorphous carbon consisting of small polycyclic aromatic carbon sheets with a high density of SO(3)H groups (ca. 2 mmol g(-1)). CCSAs were prepared from carbon precursors, which were obtained at temperatures ≤723 K, and exhibited a high catalytic performance for the esterification of acetic acid with ethanol and for the hydrolysis of cellobiose, although the surface areas were small (<5 m(2) g(-1)). In contrast, CCSAs, which were prepared from carbon precursors obtained at ≥823 K, exhibited much lower catalytic activities for both reactions, although the CCSAs had sufficient amounts of SO(3)H groups. Structural analyses, including spectroscopic analysis of CCSAs with adsorbed probe molecules, revealed that cross-linking between the polycyclic aromatic carbon sheets caused the sharp decrease in activity.

Reductive amination of aldehydes and ketones by NaBH4 using carbon-based solid acid (CBSA) as catalyst

A new, simple and convenient procedure is introduced for direct and indirect reductive amination of aldehydes and ketones with sodium borohydride. The reaction has been carried out in solid state in the presence of catalytic amount of wet carbon-based solid acid.

Carbon-based Solid Acid Catalyzed One-pot Mannich Reaction: A Facile Synthesis of β-Amino Carbonyl Compounds

A simple and efficient method for the synthesis of <TEX>$\beta$</TEX>-amino carbonyl compounds by one-pot three-component Mannich reaction of acetophenone, aromatic aldehydes and aromatic amines using a carbon-based solid acid (CBSA), as an effective and reusable catalyst, is described. The present methodology offers several advantages such as simple procedure with an easy work-up, shorter reaction times, and high yields.

Reaction Kinetics of Biodiesel Synthesis from Waste Oil Using a Carbon-based Solid Acid Catalyst

The kinetics of simultaneous transesterification and esterification with a carbon-based solid acid catalyst was studied. Two solid acid catalysts were prepared by the sulfonation of carbonized vegetable oil asphalt and petroleum asphalt. These catalysts were characterized on the basis of elemental analysis, acidity site concentration, the Brunauer-Emmett-Teller (BET) surface area and pore size. The kinetic parameters with the two catalysts were determined, and the reaction system can be described as a pseudo homogeneous catalyzed reaction. All the forward and reverse reactions follow second order kinetics. The calculated concentration values from the kinetic equations are in good agreement with experimental values.

Efficient catalytic conversion of fructose into hydroxymethylfurfural by a novel carbon-based solid acid

A novel carbon-based solid acid, which was prepared by a facile and eco-friendly approach from glucose and p-toluenesulfonic acid (TsOH), was used to catalyze fructose dehydration into 5-hydroxymethylfurfural (HMF) for the first time and exhibits excellent catalytic performance. As high as 91.2% yield of HMF was achieved in dimethyl sulfoxide (DMSO) at 130 °C after only 1.5 h. Besides, this catalyst also displayed a good reusability.

Carbon‐Based Solid Acid as An Efficient and Reusable Catalyst for One‐Pot Synthesis of Tetrasubstituted Imidazoles under Solvent‐Free Conditions

AbstractCarbon‐based solid acid catalyst was found to be highly efficient, eco‐friendly and recyclable heterogeneous catalyst for the multicomponent reaction of benzil, aromatic aldehyde, primary amine and ammonium acetate, giving rise to 1,2,4,5‐tetrasubstituted imidazoles in good to excellent yields. The present methodology offers several advantages, such as high yields, short reaction time, mild reaction condition and a recyclable catalyst with a very easy work up.

Synthesis of Sulfonated Carbon Nanocage and Its Performance as Solid Acid Catalyst

A carbon nanocage material (CKT) was first successfully sulfonated by introducing sulfophenyl groups on the surface of pore channels through benzenesulfonic acid-containing aryl radical in situ generated from the reaction of 4-aminobenzenesulfonic acid and isoamyl nitrite in water. The sulfonated carbon nanocage material (S-CKT) was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, powder small-angle X-ray diffraction and nitrogen sorption measurements. The results showed that the S-CKT still possess the high specific surface area (787 m2/g) and uniform mesoporous (pore diameter 4.7 nm) structures, although the structure of S-CKT is slightly disorder, compared with its unsulfonated precursor. S-CKT, as a carbon-based solid acid catalyst, showed good catalytic performance and reusability in the cross-Aldol condensation of ketones with aromatic aldehydes under solvent-free condition. [Dispersibility of S-CKT in H2O, DMF, EtOH (from left to right) after 6 month]

Etherification of Glycerol with Isobutylene to Produce Oxygenate Additive Using Sulfonated Peanut Shell Catalyst

A carbon-based solid acid catalyst was prepared by sulfonation of partially carbonized peanut shell, and characterized by SEM, EDS, BET analysis, FTIR spectroscopy, NH3 TPD, and TGA. The analytic results indicate that sulfonated peanut shell catalyst has an amorphous porous structure with a high acid capacity and good thermal stability and exhibits better catalytic activity for the glycerol etherification reaction than cation-exchange resin. With a molar ratio of isobutylene to glycerol of 4:1, a catalyst-to-glycerol mass ratio of 6 wt %, a reaction temperature of 343 K, and a reaction time of 2 h, glycerol was completely transformed into a mixture of glycerol ethers including mono-tert-butylglycerols (MTBGs), di-tert-butylglycerols (DTBGs), and tri-tert-butylglycerol (TTBG), and the selectivity toward the sum of the desired DTBGs and TTBG of 92.1% was obtained. Moreover, excellent reusability of the catalyst was also confirmed by repeated experiments.