High Acid Amount Research Articles

Catalytic pyrolysis of lignin to aromatic hydrocarbons over Nb/Al oxide catalyst

Catalytic fast pyrolysis (CFP) of lignin aiming monocyclic aromatic hydrocarbons (MAHs) is attractive. Five metal oxide catalysts (named c-Nb3Alx) with different Nb/Al ratios, c-Nb, c-Al, c-Nb3Al1, c-Nb3Al2 and c-Nb3Al3 were synthesized and applied to CFP of lignin. Among these catalysts, c-Nb3Al2 exhibits excellent deoxygenation ability and the highest selectivity for MAHs (77.0 %). The selectivity and deoxygenation capacity of c-Nb3Al2 for MAHs were higher than H-ZSM-5 (25) as a control. It was attributed to the large external surface area (90 m2g-1), mesoporous structure (16.15 nm) and high acid amount (2.00 mmolNH3/gcat) of c-Nb3Al2. The c-Nb3Al2 has good stability and can be regenerated by simple calcination. The selectivity of the regenerated c-Nb3Al2 for MAHs was still high at 70.1 %. Guaiacol was used to compare the difference in the deoxygenation capacity of c-Nb3Al2 and H-ZSM-5.

Low-temperature catalytic dechlorination of model plastic pyrolytic oil over zeolite catalysts

Catalytic dechlorination of model plastic pyrolytic oil was investigated over different types of zeolites and ion-exchanged 13X zeolites at the low temperatures of 20–120 °C. Among different types of parent zeolites (13X, β, MCM-41), 13X had the highest catalytic dechlorination performance. After ion exchange of 13X with Ag+, its catalytic dechlorination performance was significantly enhanced, and the chlorine removal over Ag-13X reached 97.2 % after reaction for 5 h at 120 °C. The characterization results indicated that the acidity of the zeolite governed its catalytic dechlorination performance, and higher acid amount and stronger acid strength are preferred. Different types of chlorinated compounds followed different dechlorination mechanisms. The primary chlorinated alkanes (e.g., 1-chlorooctane) underwent nucleophilic substitution by the surface –OH groups or H2O to form alcohols and HCl, or dehydrochlorination reaction to produce olefins and HCl, while higher chlorinated alkanes with adjacent hydrogen (e.g., chlorocyclohexane) mainly underwent dehydrochlorination reaction to produce olefins and HCl. Chlorinated aromatics (e.g., chlorobenzene) was removed mainly by physical adsorption. Ag-13X showed good stability, and the chlorine removal still retained 72.1 % after 102 h on stream. After four dechlorination-regeneration cycles, the chlorine removal had only a slight decrease due to the partial collapse of its structure and slight loss of its acid amount.

Preparation of ZSM-5 zeolites by sodium-free method in rotating packed bed

In industry, H-type zeolites are usually synthesized under hydrothermal conditions in the sodium-containing system, in which great deal of ammonia nitrogen wastewater will be produced during the transformation of zeolites from Na-type to H-type. In this work, we prepared ZSM-5 zeolites in the sodium-free system using organic amines in a rotating packed bed (RPB), which can greatly reduce the amount of wastewater. It was found that the ZSM-5 zeolites synthesized by isopropanolamine (MIPA) had the highest acid amount with a value of 2.331 mmol/g compared to that by other three amines, and exhibits the highest conversion of benzaldehyde with a value of 77.63% in the acetal reaction of benzaldehyde and ethylene glycol. More importantly, RPB premixing can improve the transfer of Al into the framework of ZSM-5 zeolites relative to conventional stirring technique. This work provided a new route to prepare ZSM-5 zeolites with high acid amount in sodium-free system.

Seed-assisted synthesis of Ga-MFI slabs and nanocrystal agglomerates and comparative study of acidic properties

A series of Ga-MFI zeolites were one-step synthesized following the seed-assisted strategy without using additional organic template. The effects of synthesis parameters on the framework fabrication, morphology evolution, and gallium incorporation were systematically investigated by XRD, N2-adsorption, UV-Raman, STEM, TEM, solid state NMR, NH3-TPD, and Py-IR analyses. The Si/Ga seed exhibited a highly efficient structure-directing capability in the assembly of MFI framework and the amount of the costly tetrapropylammonium hydroxide (TPA+) was thus decreased to less than one-tenth in comparison with the traditional synthesis. Crystallization temperature and pre-aging conditions played the key roles in the Ga-MFI zeolite synthesis. Both of the morphology and the intraframework gallium concentration can be facilely controlled by adding the mineralizer and surfactant. The addition of NH4F and CTAB was favorable for the formation of the slabs-form product but against to the gallium substitution. Only with the help of Si/Ga seed, the synthesized Ga-MFI nanocrystal agglomerates possess a highly accessible hierarchical mesopore structure that consisted solely of interparticle-type mesopores. Simultaneously, it also exhibited a remarkable gallium incorporation, which ensured the great acidic properties, including strong acidic strength and high acid amount. As a consequence, the Ga-MFI nanocrystal agglomerates performed the excellent catalytic activity in the LDPE degradation.

Effects of Al distribution in the Cu-exchanged AEI zeolites on the reaction performance of continuous direct conversion of methane to methanol

The effects of the organic structure-directing agent (OSDA) with or without Na cations for the synthesis of AEI zeolite on the location and content of the Al atoms in the framework as well as the Cu speciation and acidic features of the exchanged Cu/AEI zeolite catalysts and their catalytic properties in the continuous direct conversion of methane to methanol (cDMTM) were investigated. The AEI zeolite synthesized with Na cations led to more Al and a higher percentage of Al pairs than the one prepared without Na cations. Consequently, the Cu/AEI zeolite catalysts synthesized with Na cations exhibited lower apparent activation energy of methane conversion, higher methanol formation rate, and less stable ability in the cDMTM reaction due to the more active dicopper species and higher acid amount than those prepared without Na cations. Adjustment of the close Al content in the framework of the two AEI zeolites by calcination, the Cu/AEI zeolite synthesized with Na cations evidenced a higher methanol selectivity and more stable reaction performance because of the different relationship between Cu species and acid sites, such as the distance, caused by the Al distribution. The methanol formation rate of 27.3 µmol·g−1·min−1 with about 50% selectivity and stable performance in the cDMTM reaction at 350 °C were obtained. Moreover, the stability of both 5Cu/AEI zeolite catalysts could be upgraded by further calcination to diminish the acid amount, the high methanol formation rate of the 5Cu/AEI zeolite synthesized with Na cations was maintained and the reaction stability was newly attained. The 5Cu/AEI zeolite synthesized without Na cations, merely the stable performance was reached, while the methanol formation rate and selectivity seriously declined. This work contributed to the development of AEI zeolite with different Al distributions and its significant impacts on the Cu speciation and acidic properties, thus providing a valuable strategy to obtain a robust Cu/AEI zeolite catalytic system for efficient and stable methanol production from methane.

Catalytic behavior of a ZnO/TiO2 composite in the synthesis of polycarbonate diol.

ZnO/TiO2 catalysts with different ZnO contents have been prepared through equal volume impregnation method, characterized by XRD, SEM, Py-IR, ICP, XPS, NH3-TPD and N2 adsorption/desorption, and evaluated in the synthesis of polycarbonate diol (PCDL) through transesterification. The results showed that titanium zinc oxide formed in these catalysts, and the content of acidic sites varied with the ZnO content, and ZnO/TiO2 (10%) has the highest acid amount. The ZnO/TiO2 (20%) with medium acidic sites showed the highest catalytic activity. The synthesis process of polycarbonate glycol was also optimized. Under the optimal reaction conditions, the yield of PCDL was 72.5%, and the M n reached 4829 g mol-1 with a PDI of 1.6.

Clariant unveils groundbreaking catalysts developed jointly with Linde Engineering for novel ethylene production technology

Eight-membered ring small-pore zeolite of RHO-type topology has been synthesized, characterized and tested for methanol-to-olefin (MTO) reaction. The zeolite was hydrothermally crystallized from the gel with Si/Al ratio of 5.0. It showed a high BET specific surface area (812 m2 g–1), micropore volume (0.429 cm3 g–1), and acid amount (2.53 mmol g–1). Scanning electron microscopy observations showed small crystallites of about 1 μm. The zeolite was active for MTO reaction with 100% methanol conversions at 623–723 K, whereas selectivity to lower olefins changed with time.

High-temperature selective catalytic reduction of NO with NH3: Optimization of ZrO2 and WO3 complex oxides

The catalyst for selective catalytic reduction of NOx at high temperatures is significantly demanded by current gas-fired exhaust purification. In this work, the complex oxides composed of two different structures of ZrO2-WO3 and WO3/ZrO2 with zirconium as the main component were prepared for NH3-SCR of NO at high temperatures by blending method and equal volume impregnation method, respectively. Combined with XRD, NH3-TPD, FE-SEM, BET and in situ DRIFTS characterization, the effects of component optimization of two kinds of ZrO2 and WO3 complex oxides on the performance for NH3-SCR of NO were mainly studied. The optimal compatibility of ZrO2 and WO3 complex oxides was determined, and the corresponding N2 selectivity and anti-interference ability of water vapor and SO2 were further investigated. Results showed that the performance of ZrO2-WO3 prepared by blending method for NH3-SCR of NO was significantly better than that of WO3/ZrO2 prepared by impregnation method. The ZrO2-WO3 containing 20% WO3 has the best performance in NH3-SCR of NO with NO conversion higher than 90% and N2 selectivity higher than 90% at 450–650 °C, and the performance was not affected by SO2, slightly affected by competitive adsorption of water vapor at 450 °C and not disturbed by water vapor above 500 °C. Further investigation showed that the NH3-SCR of NO over the ZrO2-WO3 reaction followed both L-H and E-R mechanisms. Characterization analysis revealed that ZrO2-WO3 has finer microscopic particles, larger specific surface area, higher acid amount and stronger acid strength than WO3/ZrO2.

Activity and selectivity of Ni–Cu bimetallic zeolites catalysts on biomass conversion for bio-aromatic and bio-phenols

To improve the quality of bio-oil and minimize coke formation, ex-situ catalytic biomass pyrolysis vapor upgrading to high-grade bio-aromatic and phenol compounds with Py-GC × GC/MS at different nickel-to-copper ratios was investigated. At the same time, the deoxygenation efficiency, structure-activity relationship, deactivation mechanism and possible pathways between combined mono- and bimetallic catalysts were also demonstrated. Ni and Cu species could be well dispersed, and the HZSM-5 support maintained the MFI crystal structure after bimetallic Ni–Cu modification, but the surface area, pore volume, and total acidity decreased. Bimetallic Ni–Cu catalysts showed better deoxygenation efficiency than monometallic catalysts, which had more advantages in the preparation of aliphatic hydrocarbons (29.86%) than mono- and bimetallic catalysts, which favored the production of aromatics (28.89%). Higher-Ni-loading catalysts promoted the formation of aliphatic hydrocarbons, aromatics and alkanes due to decarboxylation, decarbonylation and aromatization reactions, and higher-Cu-loading catalysts enhanced the olefin and phenol yields due to dehydration and demethylation reactions. Overall, the highest yields of bio-aromatic compounds and phenols were46.78% and 36.34%, respectively, at Ni-to-Cu ratios of 1:1 and 1:2, due to the high total acid amount and suitable average pore size for bio-aromatics and the low acidity and large pore size for phenols. The bimetallic Ni–Cu catalyst significantly increased the quality of bio-oil and reduced coke deposition.

Sonochemical synthesis of rho-ZMOF catalyst for an enhanced CO2 cycloaddition reaction

A zeolite-like metal–organic framework with a rho topology was synthesized via a sonochemical route (rho-ZMOF(S)), and its physicochemical properties were compared with the one prepared via a conventional solvothermal route (rho-ZMOF(C)). The physicochemical properties of the samples were examined using various instrumentation. High-quality rho-ZMOF(S) was obtained only after 2 h with uniform particles of ca. 600 nm in size, whereas rho-ZMOF(C) produced after 72 h was of ca. 60 µm in size. According to the temperature-programmed desorption of ammonia, rho-ZMOF(S) showed ca. 20% higher acid amount than rho-ZMOF(C). The beneficial effect of the higher acidity with the smaller particles in rho-ZMOF(S) was demonstrated by a significant enhancement in catalytic activity for the CO2 cycloaddition reaction to epichlorohydrin.

High Acid Biochar-Based Solid Acid Catalyst from Corn Stalk for Lignin Hydrothermal Degradation.

Solid acid catalysts generally show the disadvantage of low acid amount and low recycling rate. To solve these problems, corn stalk-based solid acid catalysts were synthesized through carbonization and sulfonation processes in this work. The results showed that besides the rod-like structure inherited from raw corn stalk, the catalysts contained some small broken pieces on the surface, and the specific surface area varied from 1120 to 1640 m2/g. The functional groups (-SO3H) were successfully introduced onto the surface of the obtained solid acid catalysts. The acid amount varied between 1.2 and 2.4 mmol/g, which was higher than most of solid acid catalysts. The catalyst produced at 800 °C for 6 h in carbonation and then at 150 °C for 8 h in sulfonation had larger specific surface area and more sulfonate groups. In the degradation of lignin, the use of catalyst led to the generation of more aromatic compounds (65.6 wt. %) compared to that without using the catalyst (40.5 wt. %). In addition, a stable yield of reaction (85%) was obtained after four reuses. Therefore, corn stalk is suitable for high-value utilization to prepare high-acid amount biochar-based catalyst.

Aroma and Some Quality Characteristics of Sweet Black Colored Oskar F1 (Capsicum Annuum L. Cv. Oskar F1) Pepper Variety

The number of new varieties bred in the world is increasing day by day. İncrease in yield, possibility of marketing in domestic and foreign trade, nutritional properties of agricultural products are closely interested with developing new varieties. The evaluation of the performance of these varieties in different ecological conditions is an important study subject. Oskar F1 is a black coloured pepper also called purple colured. Oskar F1 is a registered hybrid sweet pointed pepper variety and is subject to export. Oskar F1 pepper variety is stands out in terms of marketing with its black color in addition to having high ascorbic acid amount (222.33 mg / 100g) and hexanal was found as major aroma component which creates a sensory perception as a freshly cut grass to its aroma feature.

Production of biofuels from pine needle via catalytic fast pyrolysis over HBeta

The thermal and catalytic pyrolysis of pine needles over HBeta catalysts with different SiO2/Al2O3 ratios (25 and 300) were investigated by thermogravimetric analysis (TGA) and pyrolyzer-gas chromatography/mass spectrometry. TGA showed that the main decomposition of pine needles occurred between 150 and 550 °C. The catalytic DTG curves revealed the same decomposition temperature region as the non-catalytic TG curve of pine needles. Pyrolyzergas chromatography/mass spectrometry suggested that the effective catalytic conversion of pyrolyzate intermediates and other hydrocarbons to aromatic hydrocarbons can be achieved using HBeta catalysts at 600 °C. HBeta(25) produced a larger amount of aromatic hydrocarbons than HBeta(300) because of its higher acid amounts. By increasing the reaction temperature from 500 to 700 °C, the formation of benzene, toluene, ethylbenzene, xylenes (BTEXs) and other polycyclic aromatic hydrocarbons was increased with a concomitant decrease in phenolics and other oxygenates. The formation efficiency of BTEXs was increased further by increasing the catalyst loading.

Advanced and green ozonation process for removal of clofibric acid in water system: Preparation and mechanism analysis of efficient copper-substituted MCM-48

This paper described the use of modified mesoporous molecular sieves to remove clofibric acid through catalytic ozonation. The mesoporous silicate MCM-48 and Cu-substituted MCM-48 (Cu-MCM-48) with different Cu contents were prepared by hydrothermal method in surfactant solutions. The catalyst was characterized by XRD, UV–vis, and XPS, indicating that copper was successfully doped in the framework of three-dimensional MCM-48 and Cu-O-Si linkage was formed in Cu-MCM-48 samples. The SEM and TEM graphs exhibited that the cubic arrays were highly homogeneous and well-ordered. However, high Cu contents destroyed the basic structure of pure MCM-48 and metallic nanometric clusters accumulated on the surface of samples. The degradation and mineralization of clofibric acid (CA) were investigated with the presence of Cu modified MCM-48 (Cu-MCM-48) during ozonation. When the molar ratio of Si/Cu was 60, TOC removal reached 41.1% at 60 min oxidation time. The catalytic mechanism of Cu60-MCM-48 was also investigated by using density functional theory (DFT). The radical quenching experiments revealed that hydroxyl radical (OH) and superoxide radical (O2−) were the reactive oxygen species (ROS) for CA degradation. Cu60-MCM-48 showed favorable removal efficiency in the mild acid condition and remained high Lewis acid amount after reactions according to the results of Fourier transformer infrared (FTIR) of adsorbed pyridine. Furthermore, the possible reaction routes including C1O and C4Cl bonds destroying and aromatic ring cleavage were proposed by HPLC-MS. 2-hydroxyisobutiric acid was the main intermediate in ozonation process with the presence of Cu60-MCM-48.

Hierarchical ZSM-5 zeolite designed by combining desilication and dealumination with related study of n-heptane cracking performance

The effect of the basic (NaOH) and/or acid (citric acid and EDTA-2Na) treatment of ZSM-5 zeolite has been studied comparing the structural and acidic features and their catalytic performance in n-heptane cracking. The properties of the catalysts have been elucidated using XRD, N2 low-temperature sorption, 27Al and 29Si NMR, pyridine adsorbed FTIR, NH3–TPD, SEM and TEM analysis. The results showed that the degree of desilication and dealumination of ZSM-5 zeolites was greatly dependent on the agents. NaOH obviously created new mesopores on parent ZSM-5 zeolites by desilication. Citric acid contributed to the removal of nonframework Al species, causing the increase of micropore surface area. EDTA-2Na promoted desilication and simultaneously converted part of removed framework Al species into nonframework Al species. The treatment of ZSM-5 combined with those three agents was very effective to obtain a hierarchical structure with partial breakdown of the crystallites and high acid amounts of both Bronsted and Lewis acid sites. Catalytic tests showed that the post-treated ZSM-5 catalysts had higher activity and stability than parent ZSM-5 catalyst at the same reaction temperature. The synergetic effect of Bronsted acid and Lewis acid of ZSM-5 catalyst (Z5-ACE) probably facilitated n-heptane conversion, while more clean micropore and newly created mesopores facilitated the slight increase of olefin selectivity and suppressing the formation of coke deposition in its inherent micropores to some extent.

Unexpected features of exponentially growing Tobacco Bright Yellow-2 cell suspension culture in relation to excreted extracellular polysaccharides and cell wall composition.

This article presents a new insight about TBY-2 cells; from extracellular polysaccharides secretion to cell wall composition during cell suspension culture. In the medium of cells taken 2days after dilution (end of lag phase), a two unit pH decrease from 5.38 to 3.45 was observed and linked to a high uronic acid (UA) amount secretion (47.8%) while, in 4 and 7day-old spent media, pH increased and UA amounts decreased 35.6 and 42.3% UA, respectively. To attain deeper knowledge of the putative link between extracellular polysaccharide excretion and cell wall composition, we determined cell wall UA and neutral sugar composition of cells from D2 to D12 cultures. While cell walls from D2 and D3 cells contained a large amount of uronic acid (twice as much as the other analysed cell walls), similar amounts of neutral sugar were detected in cells from lag to end of exponential phase cells suggesting an enriched pectin network in young cultures. Indeed, monosaccharide composition analysis leads to an estimated percentage of pectins of 56% for D3 cell wall against 45% D7 cell walls indicating that the cells at the mid-exponential growth phase re-organized their cell wall linked to a decrease in secreted UA that finally led to a stabilization of the spent medium pH to 5.4. In conclusion, TBY-2 cell suspension from lag to stationary phase showed cell wall remodeling that could be of interest in drug interaction and internalization study.

Catalytic conversion of 2,5-dichlorotoluene over Hβ zeolite, Ag/Hβ and Cu/Hβ catalysts in N2 or H2 atmosphere

2,6-Dichlorotoluene (2,6-DCT), 2,4-dichlorotoluene (2,4-DCT), dichlorobenzenes (DCB), and dichloroxylene (DCX) were selectively synthesized through the catalytic conversion of 2,5-dichlorotoluene (2,5-DCT) over Hβ (SiO2/Al2O3 = 25) zeolite, Ag/Hβ, and Cu/Hβ catalysts in a N2 or H2 atmosphere. When Hβ zeolite was used as the catalyst at 310−350 °C in a N2 atmosphere, DCB, 2,6-DCT, 2,4-DCT, and DCX with the selectivities of ca. 28, 15, 17, and 22% were formed as the main products. When the Ag/Hβ catalysts with high Bronsted acid amount catalyzed the conversion of 2,5-DCT, 2,4-DCT with the selectivities of 71.9–83.9% was formed at 310 and 330 °C. The catalytic activities over the Cu/Hβ catalysts were similar to that over the Hβ catalyst. In a H2 atmosphere, the Ag2/Hβ and Cu10/Hβ catalysts favored the 2,5-DCT hydrogenation to DCB with the selectivities of around 40 and 58%, respectively. The acidity and metal type of the catalyst played important roles in the catalytic conversion of 2,5-DCT to chlorinated aromatics.

Aptitude of Saccharomyces yeasts to ferment unripe grapes harvested during cluster thinning for reducing alcohol content of wine

Among the viticultural techniques developed to obtain wine with reduced alcohol content, the use of unripe grapes with low sugar and high malic acid concentration, harvested at cluster thinning, was recently explored. So far, no studies have evaluated the fermentation performances of Saccharomyces in unripe grape musts, in terms of fermentation ability and reducing malic acid contents, to improve the quality of this low-alcohol beverage. In this work, we evaluated 24 S. cerevisiae strains isolated from Italian and Croatian vineyards with different fermentation aptitudes. Moreover, four S. paradoxus were considered, as previous works demonstrated that strains belonging to this species were able to degrade high malic acid amounts in standard musts. The industrial strain S. cerevisiae 71B was added as reference. Sugar and malic acid contents were modified in synthetic musts in order to understand the effect of their concentrations on alcoholic fermentation and malic acid degradation.S. cerevisiae fermentation performances improved when glucose concentration decreased and malic acid level increased. The conditions that simulate unripe grape must, i.e. low glucose and high malic acid content were found to enhance S. cerevisiae ability to degrade malic acid. On the contrary, S. paradoxus strains were able to degrade high amounts of malic acid only in conditions that resemble ripe grape must, i.e. high glucose and low malic acid concentration. In fermentation trials when low glucose concentrations were used, at high malic acid levels S. cerevisiae strains produced higher glycerol than at low malic acid condition. Malic acid degradation ability, tested on the best performing S. cerevisiae strains, was enhanced in fermentation trials when unripe grape must was used.

Selective Production of Light Olefins from Catalytic Cracking of n-Hexane over OSDA-Free Beta Zeolites

The catalytic cracking of n-hexane for producing light olefins on Beta zeolite synthesized under organic structure-directing agent free conditions (OFB) was carried out as a model reaction of naphtha cracking. The Al-rich H-form OFB (HOFB) catalyst exhibited a short catalytic life and a low selectivity to propylene even at the lower reaction temperature of 773 K, due to its high acid amount. Dealumination of HOFB by ammonium hexafluorosilicate (AHFS) treatment and followed by nitric acid treatment resulted in the increase in the catalytic life and propylene selectivity, regardless of the reaction temperatures ranging from 773 to 923 K. This could be attributed to the lower amount of the acid sites especially the Lewis acid sites, which suppressed the secondary reactions of propylene and butenes and the hydride transfer to form coke. For example, the HOFB-AHFS(0.5 M)-HNO3(6 h) catalyst showed a very high selectivity of ca. 41 C-% to propylene even at nearly 100 % n-hexane conversion, at the higher reaction temperature of 923 K.

Propylsulfonic acid functionalized mesoporous silica catalysts for esterification of fatty acids

The catalytic properties of 3 types of mesoporous silica SBA-15 (rope, rod and fiber), with 9.2nm or 12.1nm large mesopores, were examined with respect to their morphology and pore size. Commercially available Amberlyst-15 and the small pore sized MCM-41 were used for comparison. The catalysts were prepared by functionalization of the silica supports with propylsulfonic acid (Pr-SO3H) using post-synthesis grafting with 3-mercaptopropyltrimethoxysilane as a propyl-thiol precursor. All materials remained in a well-ordered hexagonal mesoporous structure after Pr-SO3H functionalization. The performance of the Pr-SO3H-functionalized mesoporous silicas was evaluated in terms of their catalytic activity in the esterification of oleic acid with short (methanol) and long (glycerol) chain alcohols, i.e., to test the effect of the pore size on the substrate conversion and product yield. The synthesized catalysts were highly active and the product composition could be tuned by selective choice of the mesopore size. The Pr-SO3H-functionalized rope-shaped SBA-15 gave the highest catalytic activity (in terms of the highest methyl oleate and triglyceride yields and oleic acid conversion level), which was higher than that obtained with the commercial Amberlyst-15 catalyst. A high acid amount, large specific surface area and a suitable pore size are the likely reasons for the high yield gained by Pr-SO3H-functionalized rope-shaped SBA-15 silica.