High Acid Site Density Research Articles

Novel Porous Organic Polymer Catalyst with Phosphate and Sulfonic Acid Sites for Facile Esterification of Levulinic Acid.

Biomass-derived value-added materials such as levulinic acid (LA) are favorable natural resources for producing ester-based biolubricants owing to their biodegradability, nontoxicity, and excellent metal-adhering properties. However, highly active catalysts must be developed to carry out efficient esterification of LA with aliphatic alcohols, especially long-chain aliphatic alcohols. In this study, we developed a novel porous covalent organic polymer catalyst (BPOP-SO3H) with dual acid sites, phosphate and sulfonic acid sites, for the esterification of LA. The prepared BPOP-SO3H catalyst was verified using various surface analysis techniques. BPOP-SO3H exhibited 98% LA conversion with n-butanol and 99% selectivity for butyl levulinate ester within 30 min, which is superior to that of most reported catalysts. BPOP-SO3H also showed high LA conversion and ester selectivity when other aliphatic alcohols were used. Moreover, BPOP-SO3H showed good recyclability for five consecutive cycles. We believe that incorporating a high density of acid sites into a porous polymer with a large surface area and hierarchical pores is a promising approach for developing heterogeneous acid catalysts for the production of alkyl levulinate esters from LA.

RuNi/MMO Catalysts Derived from a NiAl-NO3-LDH Precursor for CO Selective Methanation in H2-Rich Gases

CO selective methanation (CO-SMET) is a promising method for deep CO removal from H2-rich gases. In this study, a series of RuNi/MMO catalysts are prepared using the support MMO-N derived from NiAl-NO3-LDHs, which was prepared from NiAl-CO3-LDHs via an acid–alcohol ion-exchange reaction. The prepared catalysts were characterized by XRD, SEM, TEM, XPS, H2-TPR, CO-TPD, CO2-TPD, NH3-TPD, and TG. The RuNi/MMO-N catalyst demonstrated excellent CO-SMET performance, successfully reducing the CO to less than 10 ppm with a selectivity greater than 50% in a reaction temperature window ranging from 180 °C to 260 °C. Compared with similar catalysts derived from NiAl-CO3-LDHs, the exceptional CO-SMET capability of the RuNi/MMO-N catalyst is suggested to be associated with a more effective hydrogen spillover, a larger number of electron-rich Ni sites, and a higher density of acid sites on the surface of RuNi/MMO-N, which are conducive to CO adsorption and the inhibition of CO2 methanation.

Sulfonic acid-type hydrothermal carbon microspheres as stable, efficient catalysts for transesterification reactions

With the aim of preparing a sulfonic acid-type solid acid catalyst having a high density of acid sites and excellent stability, this work synthesized sulfonic acid bowl-shaped hydrothermal carbon microspheres (SA-OBHCs), using amine groups as the primary sulfonic acid bonding sites. This material was synthesized via a three-step functionalization process comprising the oxidation, amidation and sulfonation of BHCs. The extent to which chlorosulfonic acid reacted with amine groups in diethylenetriamine molecules on microsphere surfaces was also investigated using density functional theory calculations. These calculations showed that the substitution reaction of primary amines proceeded less readily than that of secondary amines but provided a more stable product. The surface acid density of the SA-OBHCs was as high as 11.2 mmol·g−1 and the –SO3H groups on the SA-OBHCs were found to be thermally stable up to 200 °C. These SA-OBHCs were subsequently used to catalyze the synthesis of fatty acid methyl esters (FAMEs) from a waste frying oil model compound and methanol. Reactions performed using a methanol/oil molar ratio of 20:1 at 140 °C for 3 h gave a FAMEs yield of 93.4 %. After four reuses, an SA-OBHCs specimen provided a FAMEs yield of 77.5 %, demonstrating the significant stability of this material.

On the role of the nature and density of acid sites on mesostructured aluminosilicates dehydration catalysts for dimethyl ether production from CO2

In this work, we designed four different mesostructured acidic materials to be used as methanol dehydration catalysts for the one-pot CO2-to-DME process, in the form of physical mixtures with a Cu/ZnO/Al2O3-based commercial redox catalyst (CZA). The studied systems consist in a mesostructured γ-Al2O3 and three mesostructured aluminosilicates (namely Al-MCM-41, Al-SBA-15, and Al-SBA-16) with the same Si/Al ratio (= 15) but significantly different textural properties. The main goal of this work is to understand how the textural features can influence the acidic properties (typology, amount, strength, surface density) and, consequently, how catalytic performances can be correlated with acidic features. On this note, we found that the systems presenting both Brønsted and Lewis sites (namely the three aluminosilicates) show much better catalytic performances than γ-Al2O3, that only features Lewis sites, thus implying that Brønsted sites are more active towards methanol dehydration than Lewis sites. The three aluminosilicates, despite presenting comparable amounts of Brønsted sites, show significantly different performances in terms of selectivity to DME; particularly, Al-SBA-16, the system with the lowest surface area, proved to be the most efficient catalyst. This finding led us to infer that, besides Brønsted acidity, a high surface density of acid sites is a key factor to obtain a high dehydration activity; being methanol dehydration a bi-molecular reaction, the close proximity of two acid sites would indeed favor the kinetics of the process.

Low-Temperature NH3-SCR over Hierarchical MnO x Supported on Montmorillonite Prepared by Different Methods.

Hierarchical MnO x pillared or supported on montmorillonite were prepared by three methods, i.e., impregnation (IM), chemical precipitation (CP), and in situ deposition (SP). The catalysts were characterized by low-temperature N2 adsorption (BET), XRD, XPS, SEM, TEM, H2-TPR, NH3-TPD, NO-TPD, TPSR, in situ DRIFTS, and evaluation of catalytic performance for NH3-SCR. The best catalytic performance was obtained for catalysts prepared by SP in terms of activity and selectivity, obtaining >90% NO conversion with >95% selectivity to N2 in 100-300 °C and GHSV of 70,000 h-1. Compared to IM and CP, SP greatly simplified catalyst preparation, resulting in higher BET surface areas; a spongy pore structure; more highly dispersed, pillared MnO x species; and higher density of acid sites distributed on catalysts surface, which all contributed to its superior performance for NH3-SCR. The activity for low-temperature NH3-SCR of manganese catalysts could be widely tailored by preparation methods.

Insight into induction period of methanol conversion reaction: Reactivity of ethene-precursors over H-ZSM-5 zeolite is independent of Brϕnsted acid site density

A series of H-ZSM-5 (TZ-m, m represents different Si/Al ratios) has been prepared and their Methanol to Olefin (MTO) performance are investigated. By adjusting the catalyst weight of H-ZSM-5 loaded in the pulse micro-reactor, the total Brϕnsted acid sites (BAS) amount of TZ-m catalysts is unified. The resultant similar methanol conversion (∼24 %) over different TZ-m zeolites confirms that the MTO reaction is dominantly catalyzed by BAS. Nevertheless, the BAS density considerably influences the reaction pathways; more condensed BAS enhances the relative propagation of aromatic-based cycle to alkene-based cycle, and vice versa. However, isotopic co-feeding and switching experiment reveals that the reactivity of aromatic hydrocarbon pool (HCP) species, which has been considered as main ethene precursors, is almost independent of acid site density. Although large amounts of aromatics are generated via hydrogen transfer reactions on the sample with high acid site density, most of the confined aromatics function as coke precursors instead of active HCPs. The accumulation of such confined aromatics in zeolite channels further limits olefins mobility and their access to BAS, leading to decreased reactivity of alkene HCPs on high acid site-density samples.

Oxidation reaction mechanism of hydrothermal carbon microspheres with applications to transesterification after sulfonation

AbstractBackgroundAn efficient sulfonic acid‐type acid catalyst with high acid site density based on hydrothermal carbon microspheres (HCMs) has been developed. The reaction by which double bonds in the HCMs were oxidized to generate carboxyl groups was evaluated based on density functional theory calculations.ResultsSulfonic acid‐type HCMs (SHCMs) were prepared from HCMs through a three‐step process comprising oxidation, amidation and sulfonation. An analysis of the oxidation process indicated that the formation of carboxyl groups involved the activation of O2 molecules and CH bonds, the cleavage of CC bonds, the homolytic fission of peroxy acids and the coupling reactions of H• radicals. The formation of numerous carboxyl groups on the HCM surfaces was the key to obtaining SHCMs with a high acid density of 14.5 mmol g−1.ConclusionsThe SHCMs obtained exhibited good catalytic performance during the transesterification of waste frying oil with methanol. Reactions performed using a methanol/oil molar ratio of 9:1 at 90 °C for 5 h gave a fatty acid methyl ester yield of 85.56%. © 2022 Society of Chemical Industry (SCI).

Transition Metal Hexacyanoferrate(II) Complexes as Catalysts in the Ring-Opening Copolymerization of CO2 and Propylene Oxide

The catalytic activity of four transition metal hexacyanoferrate(II) complexes (Ni2[Fe(CN)6], Co2[Fe(CN)6], KFe[Fe(CN)6] and Zn2[Fe(CN)6]) in the ring-opening copolymerization (ROCOP) of CO2 and propylene oxide (PO) is reported here for the first time and compared with that of other hexacyanometallate compounds. Complexes were prepared by coprecipitation employing tert-butanol as complexing agent. X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, X-ray fluorescence, scanning electron microscopy, transmission electron microscopy and N2 physisorption were used to confirm the identity of the obtained materials. Except for Zn2[Fe(CN)6], which showed an amorphous nature, the complexes were constituted by aggregates of cubic nanocrystals with intra-crystalline micropores and inter-crystalline mesopores. Gas–solid phase titration with NH3 revealed the high potential of hexacyanoferrates as Lewis acid catalysts. In the case of Zn2[Fe(CN)6], the lack of structural organization led to an extremely high density of acid sites (43 μmol m−2). The resulting copolymers were analyzed via nuclear magnetic resonance spectroscopy and gel permeation chromatography. The studied transition metal hexacyanoferrate(II) catalysts showed mild activity in the target reaction, giving rise to polyethercarbonates with moderate CO2 content (9.3–18.1 wt%), random configuration (67.0–92.4% of polyethercarbonate linkages), modest molecular weights (MW, g mol−1 = 3400–20,200) and high dispersity (ĐM = 4.0–5.4). Cyclic propylene carbonate (PC) was also produced (1.4–19.8 wt%). Among all, the Co2[Fe(CN)6] complex stands as a potential catalyst for CO2/PO ROCOP due to its high CO2 uptake, selectivity and molecular weight of the obtained copolymer.

Alumina catalyst with high density of medium acid sites for N-arylpyrrolidines synthesis

The N-alkylation of amines with tetrahydrofuran (THF) to synthesize pyrrolidine compounds is an economic and environmental benign route. However, current catalytic system often suffered from harsh reaction condition and hazardous reagents. In this work, we developed an alumina nanosheet catalyst with a large amount of medium acid sites for synthesis of N-arylpyrrolidines. Nearly 100% target product yield could be obtained at 190 °C, and this catalyst could be reused at least 5 times without obvious deactivation. NH3-temperature programmed desorption (TPD) and pyridine-infrared (py-IR) revealed that the catalytic performance is positively correlated with the content of medium acid sites. In-situ IR spectrum proved that the reaction follows the carbocation mechanism. This work affords a competitive system for green sustainable chemistry.

Assessment on the Effect of Sulfuric Acid Concentration on Physicochemical Properties of Sulfated-Titania Catalyst and Glycerol Acetylation Performance

In this research, a solid acid catalyst was synthesized to catalyse glycerol acetylation into acetins. The sulphated-titania catalysts were prepared via the wet impregnation method at different sulfuric acid concentrations (5%, 10%, 15%, and 20%) and denoted as 5SA, 10SA, 15SA, and 20SA, respectively. The synthesized catalysts were characterized using FTIR, XRD, TGA, BET, NH3-TPD, XRF, and SEM-EDX. The synthesized catalysts were tested on glycerol acetylation reaction at conditions: 0.5 g catalyst loading, 100–120 °C temperature, 1:6 glycerol/acetic acid molar ratios, and 2–4 h reaction time. The final product obtained was analysed using GC-FID. An increment in sulfuric acid concentration reduces the surface area, pore volume, and particles size. However, the increment has increased the number of active sites (Lewis acid) and strong acid strength. 15SA catalyst exhibited excellent glycerol conversion (>90%) and the highest selectivity of triacetin (42%). Besides sufficient surface area (1.9 m2 g−1) and good porosity structure, the great performance of the 15SA catalyst was attributed to its high acid site density (342.6 µmol g−1) and the high active site of metal oxide (95%).

Synthesis of SAPO-34 Nanoplates with High Si/Al Ratio and Improved Acid Site Density.

Two-dimensional SAPO-34 molecular sieves were synthesized by microwave hydrothermal process. The concentrations of structure directing agent (SDA), phosphoric acid, and silicon in the gel solution were varied and their effect on phase, shape, and composition of synthesized particles was studied. The synthesized particles were characterized by various techniques using SEM, XRD, BET, EDX, and NH3-TPD. Various morphologies of particles including isotropic, hyper rectangle, and nanoplates were obtained. It was found that the Si/Al ratio of the SAPO-34 particles was in a direct relationship with the density of acid sites. Moreover, the gel composition and preparation affected the chemistry of the synthesized particles. The slow addition of phosphoric acid improved the homogeneity of synthesis gel and resulted in SAPO-34 nanoplates with high density of acid sites, 3.482 mmol/g. The SAPO-34 nanoplates are expected to serve as a high performance catalyst due to the low mass transfer resistance and the high density of active sites.

Study of the Cycloaddition of CO2 with Styrene Oxide Over Six-Connected spn Topology MOFs (Zr, Hf) at Room Temperature.

A series of MOFs with a 6-connected spn topology were synthesized (MOF-808-(Zr, Hf), PCN-777-(Zr, Hf), MOF-818-(Zr, Hf)). Through the in situ DRIFTS of NH3 adsorption-desorption, we found that the activated catalyst mainly contains Lewis acid sites. The effects of different organic ligands on the Lewis acid of the Zr6 cluster were analyzed by XPS and NH3 -TPD, and the relative Lewis acidity of the same metal was obtained: PCN-777>MOF-808>MOF-818. In the Py-FTIR results, we confirmed that MOF-818 has a higher acid site density. In the activity test, MOFs with mesoporous structure showed better catalytic activity under normal temperature and pressure. Among them, MOF-818 can still maintain a high degree of crystallinity after catalysis. Finally, we use density functional theory to propose the mechanism of the cycloaddition reaction of carbon dioxide and styrene oxide. The results show that the metal is coordinated with styrene oxide and halogens attack the β carbon of the epoxide.

Acid treated Ce modified birnessite–type MnO2 for ozone decomposition at low temperature: Effect of nitrogen containing co-pollutants and water

In this study, HNO3 treated Ce modified birnessite–type MnO2 (CexMn-AT; x = 0.01,0.1,0.2,0.5) have been designed for decomposition of ozone at low temperature (20–40 °C) in the absence or presence of nitrogen containing co-pollutants and water. The best catalyst Ce0.01Mn-AT exhibits stable ozone conversion of 94 % in nearly dry air (300 ppm of ozone, RH = 0.7 %, GHSV = 1200 L/(g.h), 20 °C) in the presence of N2O5/HNO3 pollutants. However, the ozone conversion drops to 64 % for the undoped catalyst showing the beneficial role of cerium. Additionally, the Ce0.1Mn-AT catalyst shows a stable ozone conversion of 91 % after 5 h on stream in moist air (RH = 30 %, 30 °C) in the same operating conditions as before. The high tolerance of the best acid-treated catalysts to co-pollutants and water can be explained by the high density of acid sites and oxygen vacancies which facilitate the adsorption and decomposition of ozone and allow to minimize the amount of nitrogen containing adspecies which can affect the catalytic performances for ozone decomposition.

A Carbon‐Based Solid Acid Catalyst Prepared through a One‐Step Hydrothermal Carbonization: Efficient Catalysts for Liquid‐Phase Nitrification

AbstractCarbon‐based solid acid catalysts were successfully prepared by hydrothermal carbonization method and one‐pot method using naphthalene crosslinked by formaldehyde and sulfonated by H2SO4 (98 %). The characterization results showed that the catalysts prepared by hydrothermal carbonization method had more amorphous carbon composed of aromatic carbon sheets with functional groups (−SO3H, −COOH and −OH) than the catalyst prepared by one‐pot method. The preparation conditions of hydrothermal carbonization method were optimized. The F−N−SO3H‐h‐2.49 (1 : 11) prepared under optimal conditions showed high conversion of cyclohexane (48.2 %) and selectivity to nitrocyclohexan (98.2 %) at 125 °C for liquid‐phase nitrification, attributed to high acid site density (3.08 mmol/g) and amorphous carbon structure with hydrophilic functional groups. The F−N−SO3H‐h‐2.49 (1 : 11) also showed excellent thermal stability until 460 °C. The thermal stability of the catalyst is due to mutual electron‐withdrawal of aromatic carbon sheets.

Suppression of the hazardous substances in catalytically upgraded bio-heavy oil as a precautious measure for clean air pollution controls

Bio-heavy oil (BHO) is a renewable fuel, but its efficient use is problematic because its combustion may emit hazardous air pollutants (e.g., polycyclic aromatic hydrocarbon (PAH) compounds, NOx, and SOx). Herein, catalytic fast pyrolysis over HZSM-5 zeolite was applied to upgrading BHO to drop-in fuel-range hydrocarbons with reduced contents of hazardous species such as PAH compounds and N- and S-containing species (NOx and SOx precursors). The effects of HZSM-5 desilication and linear low-density polyethylene (LLDPE) addition to the feedstock on hydrocarbon production were explored. The apparent activation energy for the thermal decomposition of BHO was up to 37.5% lowered by desilicated HZSM-5 (DeHZSM-5) compared with HZSM-5. Co-pyrolyzing LLDPE with BHO increased the content of drop-in fuel-range hydrocarbons and decreased the content of PAH compounds. The DeHZSM-5 was effective in producing drop-in fuel-range hydrocarbons from a mixture of BHO and LLDPE and suppressing the formation of N- and S-containing species and PAH compounds. The DeHZSM-5 enhanced the hydrocarbon production by up to 58.5% because of its enhanced porosity and high acid site density compared to its parent HZSM-5. This study experimentally validated that BHO can be upgraded to less hazardous fuel via catalytic fast co-pyrolysis with LLDPE over DeHZSM-5.

Catalytic improvement of biomass conversion: Effect of adding mesoporosity on MOR zeolite for esterification with oleic acid

Catalytic processes play an important role in the valorization of biomass for the production of biofuels. In this context, the effect of desilication of MOR zeolite (H-MOR-D) on the esterification of oleic acid as a model reaction for biomass conversion was investigated. Zeolite catalysts were characterized by BET, TG, NH3-TPD, XRD, XRF, FTIR and 27Al MAS NMR analysis and the results showed that the alkaline treatment caused a decrease in crystallinity and removal of sites with greater acid strength of the zeolite precursor. The conversion of oleic acid into methyl oleate catalyzed by H-MOR was less (44%) than that obtained by the treated zeolite H-MOR-D (70%), suggesting that the catalytic activity in the MOR structure does not depend only on the high density of strong acid sites. DFT calculations showed that, bulky molecules suffer molecular distortions within the confined voids, consequently the adsorption enthalpy is highly unstable limiting the formation of intermediates and thus contributing to the lower reaction rate observed experimentally in H-MOR zeolite. Desilication should be considered in projects for the synthesis of new catalysts type zeolite for the conversion of biomass crude or pre-treated, in which bulky molecules prevail.

Production of value-added aromatics from wasted COVID-19 mask via catalytic pyrolysis

In this study, wasted mask is chosen as a pyrolysis feedstock whose generation has incredibly increased these days due to COVID-19. We suggest a way to produce value-added chemicals (e.g., aromatic compounds) from the mask with high amounts through catalytic fast pyrolysis (CFP). To this end, the effects of zeolite catalyst properties on the upgradation efficiency of pyrolytic products produced from pyrolysis of wasted mask were investigated. The compositions and yields of pyrolytic gases and oils were characterized as functions of pyrolysis temperature and the type of zeolite catalyst (HBeta, HY, and HZSM-5), including the mesoporous catalyst of Al-MCM-41. The mask was pyrolyzed in a fixed bed reactor, and the pyrolysis gases evolved in the reactor was routed to a secondary reactor inside which the zeolite catalyst was loaded. It was chosen 550 °C as the CFP temperature to compare the catalyst performance for the production of benzene, toluene, ethylbenzene, and xylene (BTEX) because this temperature gave the highest oil yield (80.7 wt%) during the non-catalytic pyrolysis process. The large pore zeolite group of HBeta and HY led to 134% and 67% higher BTEX concentrations than HZSM-5, respectively, likely because they had larger pores, higher surface areas, and higher acid site density than the HZSM-5. This is the first report of the effect of zeolite characteristics on BTEX production via CFP.

MCM-41-supported tungstophosphoric acid as an acid function for dimethyl ether synthesis from CO2 hydrogenation

We mixed an MCM-41-supported tungstophosphoric acid (TPA) catalyst with a commercial CuO–ZnO–Al2O3 methanol synthesis catalyst (MSC) and optimized the mixing ratios/reaction conditions towards high performance in dimethyl ether (DME) synthesis by CO2 hydrogenation. First, a series of TPA/MCM-41 catalysts were synthesized at a TPA loading of 30, 40, 60, and 80 wt% and characterized by combining various techniques. The results of X-ray fluorescence spectroscopy confirmed the loading of stoichiometric TPA amounts in each TPA/MCM-41 catalyst, while the N2 adsorption-desorption measurements and the scanning transmission electron microscopy images were showing the decoration of MCM-41 pores with TPA clusters. X-ray diffraction and infrared spectroscopy results identified some structural distortions in TPA clusters especially at relatively low loadings and the results of temperature programmed desorption of ammonia measurements quantified the consequences of these changes in TPA structure on the acid properties. The optimized TPA loading in TPA/MCM-41 was 60 wt% with CuO–ZnO–Al2O3:TPA/MCM-41 = 4:1 at 40 000 mL CO2 gcat−1 h−1 and H2:CO2 = 3:1 at 250 °C and 45 bar. At these conditions, the rate was 1551.5 gDME kgcat−1 h−1, to the best of our knowledge, the highest rate for the direct DME synthesis from CO2 hydrogenation in a single-pass reactor. This performance was originated from the high density of acid sites in TPA/MCM-41 owing to exceptionally high surface area of MCM-41 offering a monolayer dispersion of TPA even at a TPA loading of 60 wt%. These results present a broad potential of TPA/MCM-41 as an acid function in the catalyst mixture for the single-pass DME synthesis from CO2 hydrogenation, especially if used together with an MSC specifically designed for CO2 hydrogenation.

Stabilization of acid-rich bio-oil by catalytic mild hydrotreating.

Although liquid products derived from the pyrolysis of biomass are promising for the production of petroleum-like hydrocarbon fuels, the catalytic burden of hydrodeoxygenation must be reduced to achieve feasible upgrading processes. Herein, mild hydrotreating of an acid-rich biomass pyrolysis oil (bio-oil) with an unusually high total acid number (588mg KOH/g bio-oil) was performed to stabilize the low-quality bio-oil. Ru-added TiO2-supported transition metal catalysts stabilized the bio-oil by reducing its acidity more compared to what could be achieved by Ru-free catalysts; this process also leads to lower loss of organic compounds compared to when using a Ru/TiO2 catalyst. Based on the performance of transition metal catalysts, including Ni, Co, and Cu, supported on TiO2, tungstate-zirconia, or SiO2, supported bimetallic catalysts were prepared by adding Ru to the TiO2-supported metal catalysts. The bimetallic catalysts Ru/Ni/TiO2 and Ru/Co/TiO2 exhibited good decarboxylation activity for the removal of carboxylic acids and a higher yield of organic compounds compared to that provided by Ru, which can be deemed appropriate for feedstocks when hydrodeoxygenation needs to suppress the loss of organic reactants. Using these catalysts, the carboxylic acid concentration was reduced to 319-323mg KOH/g bio-oil with organic yields of 62-63wt% at reaction temperatures 150-170°C lower than the temperature required for direct conversion of carboxylic acids to alcohols or deoxygenates. The improved catalytic hydrotreating activity of Ru-added transition metals can be attributed to the high acid site densities of these catalysts along with their improved hydrogenation activities.

Synthesis and catalytic evaluation of acidic carbons in the etherification of glycerol obtained from biodiesel production

In this paper, the catalytic behaviour of carbonaceous system (Ccs) functionalized with –SO3H groups were studied in the etherification of refined (Gly) and crude glycerol (GlyC), with benzyl alcohol (BA). This Ccs was obtained by a synthetic method with low energetic cost in only 24 h. Its catalytic activity and selectivity were studied varying the catalyst percentage (2.5, 5 and 10 wt.%), the initial reactant molar ratio and temperature (between 80 and 120 °C). A very good catalytic performance was achieved (97 % conversion after 360 min of reaction), at 120 °C, Gly:BA = 3:1 and 10 wt.% of Ccs. The high activity can be attributed to high acid site density (6.4 mmol H+/g), that also allowed us to working at lower reaction temperature (100 °C) and with less catalyst concentration (2.5 wt.%), without observing significant loss in BA conversion. Monoether (ME1) was the major product of the reaction with 72 % selectivity. The material can be reused and still gives a notable conversion of BA (about 43 %) after three successive reuses. Finally, the Ccs was active and selective to the desired products in the etherification of crude glycerol (GlyC) derived of biodiesel industry. An important BA conversion (45 %) was obtained only reducing the water content of GlyC and without carrying out any other purification and/or neutralization treatment.