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It is a challenge to accurately assess pancreatic cystic lesions (PCLs) and determine their risk. We compared the yield of tissue acquired with endoscopic ultrasound (EUS)-guided microforceps (through the needle tissue biopsy [TTNB]) with that of samples collected by EUS-guided fine-needle-aspiration (EUS-FNA), and the accuracy of analyses of each sample type in the diagnosis of mucinous PCLs.We performed a prospective open-label study of 114 consecutive adults (56.1% women; mean age, 64.2 y) undergoing EUS-FNA evaluation of PCLs (mean size, 35 mm) at 7 centers, from June 20, 2016, through August 31, 2018. Samples were collected from each cyst by FNA and microforceps; samples collected by FNA were analyzed by cytology and samples collected by TTNB were analyzed by histology. Acquisition yield was defined as the percentage of specimens collected that were adequate for cytologic or histologic analysis. Diagnoses of mucinous cysts were made based on identification of pancreatic mucinous epithelium by cytology analysis of FNA samples or histologic analysis of TTNB samples. Surgical specimens were used as the reference standard when available.The EUS-guided microforceps were successfully inserted into 97.4% (111 of 114) of PCLs. Tissue acquisition yield was significantly higher with TTNB (95 of 114; 83.3%) than FNA (43 of 114; 37.7%) (P.001). Sixty-one PCLs were determined to be mucinous based on TTNB analysis (53.5%) vs 11 with FNA analysis (9.6%) (P.001). Among PCLs categorized as equivocal, based on the level of carcinoembryonic antigen, TTNB analysis found 50% (41 of 82) to be mucinous and FNA analysis found 8.5% (7 of 82) to be mucinous (P.001). Findings from analyses of samples collected by TTNB were 100% concordant with findings from histologic analysis of surgical specimens (14 of 14), whereas only 3 of 14 findings from analysis of samples collected by FNA were in agreement with findings from surgical specimens (21.4%) (P.001). Four of 5 mucinous PCLs with advanced neoplasia (80%) were detected with TTNB compared with none with FNA (P = .04). Self-limited intracystic bleeding occurred in 7 patients (6.1%), and acute pancreatitis in 6 patients (5.3%).In a multicenter prospective study of patients undergoing EUS-FNA for evaluation of PCLs, we found TTNB collection of tissues for histologic analysis to be safe and feasible, with an acquisition yield of 83.3%. Histologic analysis of samples collected by TTNB identified a larger proportion of mucinous PCLs compared with cytologic analysis of samples collected by FNA-even among samples categorized as equivocal, based on the level of carcinoembryonic antigen. More samples collected by TTNB than FNA were found to have advanced neoplasia. Clinicaltrials.gov no: NCT02979509.

Vanadium oxide (V2O5) species has been supported on different porous clay heterostructures (with silica pillars, silica-zirconia with a molar ratio Si/Zr = 5 and silica-titania with a molar ratio Si/Ti = 5) by wetness incipient method. All catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption at &minus, 196 &deg, C, NH3 thermoprogrammed desorption (NH3-TPD), Raman spectroscopy, diffuse reflectance UV-Vis and X-ray photoelectron spectroscopy (XPS). After that, the catalytic activity of the vanadium-based catalysts was evaluated in the selective oxidation of H2S to elemental sulfur. The catalytic data show that both the activity and the catalytic stability increase with the vanadium content, obtaining the highest conversion values and sulfur yield for the catalysts with vanadium content of 16 wt.%. The comparison among all supports reveals that the incorporation of TiO2 species in the pillars of the PCH improves the resistance to the deactivation, attaining as best results a H2S conversion of 89% for SiTi-PCH-16V catalyst and elemental sulfur is the only compound detected by gas chromatography.

Background and Objectives: EUS-guided drainage, and direct endoscopic necrosectomy (DEN) of walled-off necrosis (WON) using a lumen-apposing metal stent (LAMS) is safe and effective. Early debridement of WON may improve overall clinical outcomes. The aim of this study is to perform a multicenter retrospective study to compare the clinical outcomes and predictors of success for endoscopic drainage of WON with LAMS followed by immediate or delayed DEN performed at standard intervals. Methods: Patients with WON managed by EUS-guided drainage with LAMS were divided into 2 groups: (1) those that underwent immediate DEN at the time of stent placement and (2) those that underwent delayed DEN 1 week after stent placement. DEN was subsequently performed every 1–2 week (s). Technical success (successful placement of LAMS), adverse events (AEs), and clinical success (complete resolution of the WON) were evaluated. Results: Totally, 271 patients underwent WON drainage with LAMS: 69 who underwent immediate DEN and 202 who underwent delayed DEN. The technical success for LAMS placement was 100% in both groups. There was no significant difference in the overall procedural AEs between the immediate and delayed DEN groups (P = 7.2% vs. 9.4%; P = 0.81). Stent dislodgement during index endoscopy occurred in three patients in the immediate DEN group compared to zero in the delayed DEN group (P = 0.016); all three dislodgements occurred during necrosectomy. Clinical success for WON resolution in the immediate DEN group was 91.3% compared to 86.1% in the delayed DEN group (P = 0.3). The mean number of necrosectomy sessions for WON resolution was significantly lower in the immediate DEN group compared to the delayed DEN group (3.1 vs. 3.9, P < 0.001). Performing DEN at the time of stent placement was an independent predictor for resolution of WON with lesser number of DEN sessions (odds ratio 2.3; P = 0.004). Conclusions: DEN at the time of initial stent placement reduces the number of necrosectomy sessions required for successful clinical resolution of WON.

Backgrounds and Objectives: No study on the use of lumen-apposing fully covered self-expanding metal stent (LAMS) to drain pancreatic fluid collections (PFCs) has evaluated outcomes of patients in the outpatient setting. The objective of this multicenter study was to evaluate the clinical outcomes, success rate, and adverse events of the LAMS for endoscopic ultrasound (EUS)-guided transmural drainage of patients with symptomatic PFCs on an inpatient versus an outpatient basis. Methods: This was a multicenter, retrospective study conducted at 4 tertiary care centers. Results: We identified eighty patients with PFCs in whom EUS-guided transmural drainage using the LAMS was performed. The mean age of the patients was 53.1 years old. Mean size of the PFC was 11.8 ± 5.1 cm. A total of 33 patients had PFCs drained in an outpatient setting while 47 patients underwent PFC drainage as inpatients. The overall technical success (ability to access and drain a PFC by placement of transmural stents) was 98.7% (79 patients). There was no statistically significant difference in the technical success rate between the inpatient and outpatient groups (100% vs. 98%, respectively, P = 1). There was no significant difference in resolution of PFCs in the inpatient and outpatient groups (91% vs. 87% respectively; P = 1). The number of procedures required for PFC resolution was significantly lower in the inpatient group as compared to the outpatients (2.3 vs. 3.1 respectively, P = 0.025). Procedure-related adverse events were significantly lower in the inpatient group compared to the outpatient group (P < 0.01). There was no significant difference in the 2 groups in terms of development of adverse events requiring endoscopic reintervention within 30 days of initial stent placement (P = 0.69). Conclusion: This study shows that LAMS placement for PFCs can be performed safely on an outpatient basis with overall technical and clinical outcomes that are comparable to those seen in inpatients.

[EN] Vanadium supported on pure (Al2O3, ZrO2) or mixed zirconia-alumina (with Al/(Al + Zr) ratio of 0.75 or 0.25) catalysts have been prepared by wet impregnation, using homemade prepared supports. The catalysts have been characterized and tested in the oxidative dehydrogenation (ODH) of ethane and in the methanol aerobic transformation. The catalytic performance strongly depends on the nature of the metal oxide support. Thus, activity decreases in the order: VOx/ZrO2 > VOx/(Al,Zr-oxides) > VOx/Al2O3. On the other hand, at low and medium ethane conversions, the selectivity to ethylene presents an opposite trend: VOx/Al2O3 > VOx/(Al,Zr-oxides) > VOx/ZrO2. The different selectivity to ethylene at high conversion is due to the lower/higher initial ethylene formation and to the extent of the ethylene decomposition. Interestingly, VOx/(Al,Zr-oxides) with low Zr-loading present the lowest ethylene decomposition. The catalytic results obtained mainly depend on the nature of the supports whereas the role of the dispersion of vanadium species is unclear. In methanol oxidation, the catalysts tested present similar catalytic activity regardless of the support (Al2O3, ZrO2 or mixed Al2O3-ZrO2) but strong differences in the selectivity to the reaction products. Thus, dimethyl ether was mainly observed on alumina-supported vanadium oxide catalysts (which is associated to the presence of acidic sites on the surface of the catalyst, as determined by TPD-NH3). Formaldehyde was the main reaction product on catalysts supported on Zr-containing oxides (which can be related to a low presence of acid sites). In this article, the importance of the presence of acid sites in ethane ODH, which can be estimated using the methanol transformation reaction, is also discussed., The authors would like to acknowledge the DGICYT (CTQ2015-68951-C3-1-R and MAT2017-84118-C2-1-R projects), the Secretary of State for International Cooperation in Spain (Project AP/040992/11) and FEDER for financial support. B.S. also thanks the University of Valencia (UV-INV-AE16-484416).

Background Afferent loop syndrome (ALS) is traditionally managed surgically and, more recently, endoscopically. The role of endoscopic ultrasound-guided entero-enterostomy (EUS-EE) has not been well described. The aim of this study was to assess the technical and clinical success and safety of EUS-EE. Methods This was a multicenter, retrospective series at six centers in patients with ALS treated by EUS-EE. Data on patients treated with enteroscopy-assisted luminal stenting (EALS) at a single center were also collected. Results 18 patients (mean age 64.2 years, 72 % post-pancreaticoduodenectomy, 10 female) underwent EUS-EE. The most common symptoms were vomiting (27.8 %) and jaundice (33.3 %). Clinical success included resolution of symptoms in 88.9 % and improvement to allow hospital discharge in 11.1 %. Technical success was achieved in 100 % of cases, with a mean procedure time of 29.7 minutes. The most common procedure was a gastro-jejunostomy (72.2 %). Three adverse events (16.7 %) occurred (two mild, one moderate). When compared with data on EALS, patients treated with EUS-EE needed fewer re-interventions (16.6 % vs. 76.5 %; P Conclusion EUS-EE seems to be safe and effective in the treatment of ALS. Indirect comparison with EALS suggested that EUS-EE is associated with a reduced need for re-intervention.

[EN] A series of W-V-O catalysts with different m-WO3 and h-WO3 phase contents were hydrothermally synthesized by employing different tungsten, vanadium, and ammonium precursors and characterized by powder XRD, N-2 adsorption, SEM, X-ray energy-dispersive spectroscopy, thermogravimetric analysis, Raman and FTIR spectroscopy, NH3 temperature programmed desorption, H-2 temperature-programmed reduction, and XPS. Finally, the acid/redox properties were analyzed by using aerobic transformation of methanol as a characterization reaction. A correlation between phase composition as well as acid and redox properties was observed, which were correlated to the catalytic performance of the title materials in a one-pot oxydehydration reaction of glycerol. The hexagonal tungsten bronze (h-WO3) phase shows a significantly higher concentration of acid sites than monoclinic m-WO3, so that the acid properties of W-V-O oxides are directly related to the presence of h-WO3 crystals. The presence of a higher concentration of acid sites in V-containing h-WO3 crystals is a key factor to achieve high selectivity to both acrolein and acrylic acid during one-pot glycerol oxydehydration. Also, V sites in h-WO3 show higher selectivity in the consecutive reaction (partial oxidation of acrolein to acrylic acid), while V sites in the m-WO3 phase fundamentally lead to the formation of carbon oxides., The authors acknowledge the DGICYT in Spain, CTQ2015-68951-C3-1-R and CTQ2015-68951-C3-3-R. Authors from ITQ also thank Project SEV-2016-0683 for financial support. D. D. thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). The research group of Prof. Fabrizio Cavani (University of Bologna, Italy)and Consorzio INSTM (Firenze) are gratefully acknowledged for a PhD grant to A. C. Authors also thank the Electron Microscopy Service of Universitat Politecnica de Valencia for their support.

This review deals with an analysis of the main structural and reactivity properties of mixed oxide systems containing vanadium oxide as the key component in catalysts for gas-phase reactions, mainly oxidations. Particular focus is placed on catalysts showing intrinsic bi-functional properties, where the combination of both acidic/basic properties and redox V-sites is a requisite for achieving optimal catalytic performance. For the selected catalytic systems, structure–reactivity correlations that have been proposed in many decades of literature were analysed, with the aim of shedding light on the molecular-level aspects of current processes and facilitating a more rational design of future catalysts.

[EN] Glycerol surplus from biodiesel synthesis still represents a major problem in the biofuel production chain. Meanwhile, those in the acrylic acid market are looking for new processes that are able to offer viable alternatives to propylene-based production. Therefore, acrylic acid synthesis from glycerol could be an effective solution to both issues. Among the viable routes, one-pot synthesis theoretically represents the most efficient process, but it is also highly challenging from the catalyst design standpoint. A new class of complex W MoV mixed-oxide catalysts, which are strongly related to the hexagonal tungsten bronze structure, able to directly convert glycerol into acrylic acid with yields of up to 51% are reported., The authors from the Instituto Tecnologia Quimica would like to thank the Spanish Government (Project CTQ2012-37925-C03-1 and program Severo Ochoa SEV-2012-0267) for financial support. CIRI Energia e Ambiente ALMA MATER STUDIORUM, Universita di Bologna, is acknowledged for the grant to A.C. E.G.G. acknowledges financial support from the Spanish Government through the project MAT2010-19837-C06-05.

Accessory spleens and splenosis represent the congenital and acquired type of ectopic splenic tissue. Generally, they are asymptomatic entities posing as solid hypervascular masses at the splenic hilum or in other organs, such as the pancreas. Intrapancreatic ectopic spleen mimics pancreatic neoplasms on imaging studies, and due to the lack of radiological diagnostic criteria, patients undergo unnecessary distal pancreatectomy. We present the first case of intrapancreatic ectopic spleen in which the concomitant use of needle-based probe confocal laser endomicroscopy and fine-needle aspiration supported the final diagnosis.

Background and study aims Endoscopic ultrasound-guided gastroenterostomy (EUS-GE) in malignant gastric outlet obstruction (GOO) appears to be promising; however, its role in benign GOO is unclear. The aim of this study was to ascertain the clinical efficacy and safety of EUS-GE in benign GOO. Patients and methods This was an international retrospective series involving 5 tertiary centers. Consecutive patients who underwent EUS-GE between 1/2013 – 10/2016 for benign GOO were included. The primary endpoint was the rate of clinical success defined as ability to tolerate oral intake without vomiting. Secondary endpoints included technical success and rate of adverse events (AE). Results Overall, 26 patients (46.2 % female; mean age 57.7 ± 13.9 years) underwent EUS-GE for benign GOO due to strictures from chronic pancreatitis (n = 11), surgical anastomosis (n = 6), peptic ulcer disease (n = 5), acute pancreatitis (n = 1), superior mesentery artery syndrome (n = 1), caustic injury (n = 1), and hematoma (n = 1). Technical success was achieved in 96.2 %. Dilation of the lumen apposing metal stent was performed in 13/25 (52 %) with a mean maximum diameter of 14.6 ± 1.0 mm. Mean procedure time was 44.6 ± 26.1 min. Clinical success was observed in 84.0 % with a mean time to oral intake of 1.4 ± 1.9 days and a median follow-up of 176.5 (IQR: 47 – 445.75) days. Rate of unplanned re-intervention was 4.8 %. 3 AE were noted including 2 misdeployed stents and 1 gastric leak needing surgical intervention following elective GE stent removal. Conclusions EUS-GE is a promising treatment for benign GOO. Larger and prospective data are needed to further validate this novel endoscopic technique in treating benign GOO of various etiologies.

Background and aims Benign gastrointestinal (GI) strictures are often refractory to standard endoscopic interventions. Fully covered coaxial lumen-apposing metal stents (LAMS) have emerged as a novel therapy for these strictures. The aim of this study was to evaluate the safety and efficacy of LAMS for refractory GI strictures. Patients and methods A retrospective analysis was performed for patients who underwent LAMS placement for benign luminal strictures in three US centers between January 2014 and December 2016. The primary outcomes were technical success and initial clinical success of LAMS placement. Secondary outcomes were stent migration, rate of re-intervention, and adverse events. Results A total of 49 patients underwent 56 LAMS placement procedures. Previous treatment had failed in 39 patients (79.6 %), and anastomotic strictures were the indication in 77.6 % (38/49), with the most common site being gastrojejunal (34.7 % [17/49]). Technical success was achieved in all procedures and initial clinical success was achieved in 96.4 % of all procedures (54/56). Patient initial clinical success was 95.9 % (47/49). Stent migration occurred in 17.9 % of procedures, and was more likely to occur at sites in the lower GI tract (P = 0.02). The mean stent dwell time was 100.6 days, and the mean follow-up was 169.8 days. Minor adverse events, not requiring hospitalization, occurred in 33.9 % of procedures, including subsequent stricture progression (10.7 %). In cases where LAMS were removed, mean follow-up time was 102.2 days. The re-intervention rate was 75 % at 300 days follow-up after stent removal. Of the LAMS placed at anastomotic strictures, 36.4 % required re-intervention, with approximately two-thirds of these re-interventions requiring placement of a new stent or surgery. Conclusion LAMS placement was successful for the management of refractory GI strictures, with good technical and initial clinical success rates. However, re-intervention rates after LAMS removal were high, and many strictures were not resolved by an extended period of stenting with these coaxial stents. LAMS placement offers additional therapeutic options and in selected cases might be considered a destination therapy for patients with recalcitrant benign strictures.

Background and study aims Double endoscopic bypass entails EUS-guided gastroenterostomy (EUS-GE) and EUS-guided biliary drainage (EUS-BD) in patients who present with gastric outlet and biliary obstruction. We report a multicenter experience with double endoscopic bypass. Patients and methods Retrospective, multicenter series involving 3 US centers. Patients who underwent double endoscopic bypass for malignant gastric and biliary obstruction from 1/2015 to 12/2016 were included. Primary outcome was clinical success defined as tolerance of oral intake and resolution of cholestasis. Secondary outcomes included technical success, re-interventions and adverse events (AE). Results Seven patients with pancreatic head cancer (57.1 % females; mean age 64.6 ± 12.5 years) underwent double endoscopic bypass. Four patients had EUS-GE and EUS-BD performed during the same session with a mean procedure time of 70 ± 20.4 minutes. EUS-GE and EUS-BD were technically successful in all patients, all of whom were able to tolerate oral intake with resolution of cholestasis in 6 (87.5 %). One patient had a repeat EUS-BD with normalization of bilirubin. There were no adverse events. Conclusions Double endoscopic bypass is feasible and effective when performed by experienced operators. Studies comparing this novel concept to existing techniques are warranted.

Endoscopic ultrasound-guided gastrojejunostomy (EUS-GJ) with placement of a lumen-apposing metal stent is a minimally invasive and efficacious procedure for gastric outlet obstruction (GOO) patients not amenable to surgery. Laparoscopic gastrojejunostomy (Lap-GJ) has traditionally been the standard of care. No direct comparison between EUS-GJ and Lap-GJ has been described. Our aim was to compare the clinical outcomes, success rate, and adverse events (AE) of EUS-GJ with Lap-GJ.Patients with GOO from 4 academic centers in 3 countries were included. Technical success was defined as successful creation of a gastrojejunostomy. Clinical success was defined as the ability to tolerate a diet postprocedure.Data were collected on 54 patients. A total of 25 patients underwent EUS-GJ (male n=11, mean age 63.9 y) and 29 patients underwent Lap-GJ (male n=22, mean age 75.8 y). Technical success was achieved in 29 (100%) Lap-GJ group patients and 23 (88%) in the EUS-GJ group (P=0.11). AEs occurred in 41% (n=12) of patients in the Lap-GJ group and 12% (n=3) in the EUS-GJ group (P=0.0386). According to the Clavien-Dindo Classification, the Lap-GJ group AEs were grade I (n=4), grade II (n=5), grade III (n=2), and grade V (n=1); the EUS-GJ AEs were grade II (n=2) and grade V (n=1).Although the EUS-GJ group contained more complex patients, efficacy was similar between the groups. AEs were significantly lower in the EUS-GJ group. EUS-GJ is a safe and efficacious, minimally invasive option for patients with GOO.

Background and Aims: ERCP is challenging in patients with Roux-en-Y gastric bypass (RYGB) anatomy. EUS-guided gastrogastrostomy (GG) creation is a promising novel technique to access the excluded stomach to facilitate conventional ERCP. We aimed to compare procedural outcomes and adverse events (AEs) between EUS-guided GG-assisted ERCP (EUS-GG-ERCP) and enteroscopy-assisted ERCP (e-ERCP) in patients with RYGB. Methods: Patients with RYGB anatomy who underwent EUS-GG-ERCP or e-ERCP between 2014 and 2016 at 5 tertiary centers were included. The primary outcome was technical success of ERCP, defined as successful cannulation of the selected duct with successful intervention as intended. Secondary outcomes included total procedural time (in the EUS-GG group, total procedural time included EUS-GG creation plus ERCP procedure time), length of hospital stay, and rate/severity of AEs graded according to the American Society for Gastrointestinal Endoscopy lexicon. Results: A total of 60 patients (mean age, 57.2 ± 13.2; 75% women) were included, of whom 30 (50%) underwent EUS-GG-ERCP and 30 (50%) underwent e-ERCP (double-balloon enteroscope ERCP, 19; single-balloon enteroscope ERCP, 11). The technical success rate was significantly higher in the EUS-GG-ERCP versus the e-ERCP group (100% vs 60.0%, P

Background and study aims EUS-guided gastroenterostomy (EUS-GE) is a novel procedure that potentially offers long-lasting luminal patency without the risk of tumor ingrowth/overgrowth. This study compared the clinical success, technical success, adverse events (AEs), length of hospital stay (LOHS) and symptom recurrence in EUS-GE versus SGJ. Methods This was a multicenter international retrospective comparative study of EUS-GE and SGJ in patients with malignant gastric outlet obstruction (GOO) who underwent either EUS-GE or SGJ. EUS-GE was performed using lumen apposing metal stents. Results A total of 93 patients with malignant GOO treated with either EUS-GE (n = 30) or SGJ (n = 63) were identified. Peritoneal carcinomatosis was present in 13 (43 %) patients in the EUS-GE group and 7 (11 %) patients in the SGJ group (P Conclusions EUS-GE is associated with equivalent efficacy and safety as compared to surgical GJ. This is the first comparative trial between both techniques and suggests EUS-GE as a non-inferior but less invasive alter to surgery.

Background and Aims EUS-guided fine-needle core biopsy sampling is a safe and effective technique for diagnosis of focal liver lesions. However, data are limited in its role in parenchymal disease. We evaluated the utility of EUS-guided parenchymal liver biopsy sampling with a modified 1-pass wet suction technique (EUS-modified liver biopsy sampling [EUS-MLB]) in patients with unexplained increase in liver-associated tests. Methods We retrospectively evaluated the safety and efficacy of EUS-MLB in patients referred for EUS to evaluate for biliary obstruction and pancreatic disorders but with associated unexplained liver tests. EUS-MLB was performed during the same session after biliary obstruction was excluded. Results One hundred sixty-five consecutive patients underwent EUS-MLB. The median age was 52 years (interquartile range [IQR], 42-65). Sixty-eight patients (41%) were men. The median of the maximum intact core tissue length was 2.4 cm (IQR, 1.8-3.5). The median total specimen length (TSL) was 6 cm (IQR, 4.3-8). The median number of complete portal tracts (CPTs) per TSL was 18 (IQR, 13- 24). The mean number of CPTs per sample length was 7.5 cm. Adverse events were uncommon (1.8%) and included abdominal pain and self-limited hematoma. Conclusions EUS-guided fine-needle biopsy sampling using a novel 19-gauge core needle with a modified 1-pass 1 actuation wet suction technique (EUS-MLB) is a safe and effective way to evaluate patients with unexplained liver tests abnormalities who are undergoing EUS for exclusion of biliary obstruction.

[EN] The design of suitable catalysts for the one-pot conversion of glycerol into acrylic acid (AA) is a complex matter, as only fine-tuning of the redox and acid properties makes it possible to obtain significant yields of AA. However, fundamental understanding behind the catalytic phenomenon is still unclear. Structure-reactivity correlations are clearly behind these results, and acid sites are involved in the dehydration of glycerol into acrolein with vanadium as the main (or only) redox element. For the first time, we propose an in-depth study to shed light on the molecular-level relations behind the overall catalytic results shown by several types of V-containing catalysts. Different multifunctional catalysts were synthesized, characterized (>X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, temperature-programmed reduction, and temperature-programmed desorption of ammonia), and tested in a flow reactor. Combining the obtained results with those acquired from an in situ FTIR spectroscopy study with acrolein (a reaction intermediate), it was possible to draw conclusions on the role played by the various physicochemical features of the different oxides in terms of the adsorption, surface reactions, and desorption of the reagents and reaction products., The Instituto de Tecnologia Quimica thanks the Spanish Government-MINECO projects (CTQ2015-68951-C3-1-R and SEV-2012-0267). CIRI Energia e Ambiente (University of Bologna) is acknowledged for a Ph.D. grant to A.C. Consorzio INSTM (Firenze) is acknowledged for a Ph.D. grant to C.B.

Several CeO2 and CuO-CeO2 catalysts were prepared using different methods, i.e., a homogeneous precipitation with urea, a nanocasting route using CMK-3 carbon as a hard template and a sol–gel process using Poly(methyl methacrylate) (PMMA) polymer as a soft template, and tested in the total oxidation of propane. The catalysts were characterized by a number of physicochemical techniques (XRD, N2 adsorption, TPR, XPS, Raman spectroscopy) showing distinct characteristics. For each series, Cu-Ce-O catalysts with low Cu-loadings (5 wt % CuO) showed the highest activity, higher than those samples either without copper or with high Cu-loading (13 wt % CuO). The incorporation of copper leads to an increase of the concentration of bulk defects but if the Cu-loading is too high the surface area drastically falls. The highest activity in the total oxidation of propane was achieved by Cu-containing ceria catalysts synthesized using a polymer as a template, as this method yields high surface area materials. The surface area and the number of bulk/sub-surface defects of the ceria seem to be the main properties determining the catalytic activity., The authors would like to acknowledge the DGICYT in Spain CTQ2012-37925-C03-2, CTQ2015-68951-C3-1-R, CTQ2015-68951-C3-3-R. Authors from ITQ also thank Project SEV-2012-0267 for financial support. B.S, R.S and A.M.D also thank UV-INV-AE16-484416.

We report on a study of the key reaction parameters in glycerol oxidehydration into acrylic acid over W–V–Nb mixed oxides with a hexagonal tungsten bronze structure. This investigation demonstrated that the optimal control of the two consecutive steps of acid-catalysed glycerol dehydration into acrolein and aldehyde oxidation into acrylic acid, and of the parallel reaction of acrolein transformation into by-products (ketals and oligomers), was achieved in the presence of a defined glycerol-to-oxygen inlet ratio. Indeed, oxygen played the fundamental role of accelerating the oxidation of the intermediately formed acrolein into acrylic acid, by allowing a greater concentration of the oxidizing V5+ sites. In fact, an unprecedented higher yield to acrylic acid and acrolein compared to W–V bronzes was registered (maximum acrylic acid yield 50.5%) together with an increase of more than one order of magnitude in productivity, because of both the greater concentration of glycerol used in the inlet feed and the lower contact time needed. Further experiments were carried out by reacting acrolein and methanol in oxidative conditions, the latter as a model molecule for the determination of surface acid and redox properties.