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The role of hydrophobic effects of dealuminated mordenites (Si/Al ratios varying from 7 to 100) has been investigated in two reactions carried out in aqueous/alcoholic media: hydroxymethylation of furfuryl alcohol with aqueous formaldehyde and hydration of phenyl-acetylene in alcohol medium. For both reactions, initial rates and turn over frequencies (TOF) increase in a significant extent with increasing Si/Al ratios. It is shown that the differences thus observed in the TOF values are characteristic of variations in the hydrophobicity of the various dealuminated mordenites, which is confirmed by the corresponding increase of the hydrophobicity parameter h, determined by thermogravimetric analysis of such samples. The hydrophobic character of the zeolites is also discussed in terms of the softness and activity of the corresponding Brönsted acid sites.

Hydroxymethylation of furfuryl alcohol with aqueous formaldehyde, yielding selectively 2,5-bis(hydroxymethyl)furan, has been carried out at 338 K in the presence of a highly dealuminated H-form mordenite. Kinetic analysis of the experimental results allows to propose an original kinetic law involving two types of catalytic sites. According to furfuryl alcohol concentration, there is competition, or not, upon these two types of sites.

Liquid-phase alkylation of naphthalene with cyclohexyl derivatives as alkylating agents has been studied over HM and HY zeolites. The reaction can be carried out efficiently over HY zeolites, for which high conversions and good selectivities in 2,6- and 2,7-dicyclohexyl naphthalenes (DCN) are obtained after very short reaction times. The ratio 2,6-DCN/2,7-DCN is near to 1, as in the case of the isopropylation reaction over the same catalysts. Such a result is in agreement with the values of critical diameters of 2,6- and 2,7-dicyclohexyl and diisopropyl naphthalenes, calculated by molecular mechanics. The 2,6-dicyclohexyl-naphthalene is a crystalline compound which is easily separated from the reaction mixture by crystallization, which constitutes an interesting advantage of cyclohexylation in comparison with isopropylation.

The acylation reaction of 2-butylbenzofuran with p-anisoyl chloride and p-anisic acid in the presence of faujasite type zeolites, in the liquid phase, is reported. A good initial selectivity to the 3-acylated derivative is obtained, but the selectivity decreases with time. This result is explained by the involvement of a deacylation-reacylation process.

Photocatalytic oxidation of substituted toluenes was investigated on irradiated TiO2 and TiO2 combined with HY15 and HY20 zeolites. In all cases the oxidation occurred in the first step exclusively on either one substituent or the other, but never on both simultaneously. In the presence of a zeolite, photooxidation conversion was higher than that obtained without zeolite.

Interesting basic zeolites have been prepared by impregnating CsNaX zeolite with various loadings of cesium acetate in order to improve, after calcination, the basic character of the solid and to benefit from the cage effect in fine chemistry. In the range of 0 up to 26 cesium atoms per unit cell, X-ray powder diffraction shows that the crystallinity is largely retained after the generation of the basic species. The microporous volume values indicate that an interesting space is available for fine chemistry. For characterizing the surface chemical properties of the basic post-synthetically modified CsNaX zeolites, the stepwise thermodesorption of CO2 (TPD) has been studied. Experimental conditions allowing an accurate determination of the basic species are described. The modified zeolites with various loadings have been compared under these conditions. For loadings below 16 cesium atoms per unit cell, a linear relationship is established between the amount of desorbed CO2 (molecules per unit cell), up to 550°C, and the impregnated cesium loading (atoms per unit cell). This result supports the hypothesis that the active cesium species are homogeneously located inside the cages of the CsNaX zeofite. The slope of the straight line (0.44) indicates that one cesium oxide per zeolite cage is generated, leading upon CO2 adsorption to a carbonate species (Cs2CO3). For loadings higher than 16 cesium atoms per unit cell, a saturation is observed for the amount of desorbed CO2 up to 550°C along with an increase of the amount of desorbed CO2 above 550°C corresponding to a deposition of basic species on the external surface of the solids.

Bulletin des Sociétés Chimiques BelgesVolume 100, Issue 11-12 p. 865-872 Article An Attempt to Rationalize Hydroprocessing of Cyclic Heteroaromatics Over Sulfided Catalysts Through a Common Limit Step: Hydrodearomatization Jacques Joffre, Jacques Joffre Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this authorPatrick Geneste, Patrick Geneste Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this authorJean-Baptiste Mensah, Jean-Baptiste Mensah Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this authorClaude Moreau, Claude Moreau Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this author Jacques Joffre, Jacques Joffre Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this authorPatrick Geneste, Patrick Geneste Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this authorJean-Baptiste Mensah, Jean-Baptiste Mensah Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this authorClaude Moreau, Claude Moreau Laboratoire de Chimie Organique Physique et Cinétique Chimique Appliquées, C.N.R.S., U.R.A. 418, Ecole Nationale Supérieure de Chimie, 8, rue Ecole Normale, 34053 Montpellier CédexSearch for more papers by this author First published: 1991 https://doi.org/10.1002/bscb.19911001111Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume100, Issue11-121991Pages 865-872 RelatedInformation

ChemInformVolume 21, Issue 27 Preparative Organic Chemistry ChemInform Abstract: Hydroprocessing of Substituted Benzenes Over a Sulfided CoO-MoO3/γ-Al2O3 Catalyst. C. MOREAU, C. MOREAU Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this authorJ. JOFFRE, J. JOFFRE Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this authorC. SAENZ, C. SAENZ Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this authorP. GENESTE, P. GENESTE Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this author C. MOREAU, C. MOREAU Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this authorJ. JOFFRE, J. JOFFRE Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this authorC. SAENZ, C. SAENZ Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this authorP. GENESTE, P. GENESTE Lab. Chim. Org. Phys., Cinet. Chim. Appl., CNRS, 34075 Montpellier, Fr.Search for more papers by this author First published: July 3, 1990 https://doi.org/10.1002/chin.199027091AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue27July 3, 1990 RelatedInformation

The performance of titania-supported molybdenum carbide, nitride, phosphide and oxide catalysts was compared for catalytic hydrodeoxygenation (HDO) of phenol. Phenol was selected as a stable model component for lignin degradation products in fast pyrolysis bio-oil. The synthesis and formation path of the materials was evaluated by the use of complementary characterization techniques (XRD, TPR and TGA–MS). All the catalysts showed promising catalytic performance during testing in a fixed-bed reactor set-up at a temperature of 350 °C and total pressure of 25 bar, and the highest activity was achieved with 15 wt% Mo2C/TiO2. A high selectivity towards benzene was observed with all catalysts. MoP supported on TiO2 showed the strongest tendency to aromatic ring hydrogenation and also a significant selectivity (10% level) towards methylcyclopentane, indicating contributions of acidic surface chemistry. Thus, Mo based materials are active and promising materials for establishing selectivity control in HDO of bio-oils.

The catalytic hydration reaction of alkynes over modified Y-faujasite zeolites is reported. Protonic, Ce3+, and Ca2+ exchanged Y zeolites are shown to be efficient catalysts for this reaction; the case of the Hg2+ exchanged zeolite is also discussed.

A series of catalysts containing tungsten and nickel on a γ-alumina carrier were examined with respect to surface acidity. The studies focused on the behaviour of sulphided samples to which various techniques were applied. In agreement with prior studies on Co-Mo catalysts, infrared spectroscopy of adsorbed pyridine showed that both Brönsted and Lewis acidic sites are present on the calcined Ni-W samples, but Brönsted acidity can no longer be detected after sulphiding. Other probes (ammonia or piperidine) substantiated these conclusions. Moreover, gravimetric adsorption-desorption studies on ammonia confirmed that Brönsted acidity is not a major characteristic of the sulphide catalysts. The lack of strong Brönsted acidity was also demonstrated by measuring the rates of cyclohexanol dehydration or cyclohexylamine coupling carried out on the series of sulphides Ni-W catalysts. Therefore, it was proved that acidic mechanisms do not play any major role in catalysis by sulphides. In contrast, the sulphide catalysts show a better aptitude than typical cracking catalysts for isomerizing and cracking 3-methylpentane under hydrodesulphurization conditions but the product selectivity is different. The occurrence of a metallic-type catalysis is suggested, which could also operate in hydrodenitrogenation.

The hydroprocessing of nitrogen-containing model compounds such as pyridine, quinoline, acridine, pyrrole and carbazole was studied using a batch method at 340°C and 70 bar H2 over sulphided NiO-MoO3/Al2O3 and NiO-WO3/Al2O3 catalysts, where it was found that saturation of the heteroaromatic rings always occurs prior to any cleavage of C-N bonds, generally Csp3-N bonds. The rates of hydrogenation of the heteroaromatic rings were shown to be mostly influenced by the aromaticity of these rings (π-electron delocalization) and not by the basicity of the nitrogen atom. On the other hand, the basicity of nitrogen atoms considerably influences the cleavage of Csp3-N bonds in the absence of steric effects.

The hydrogenation of substituted benzenes (R = Et, Ph, c-C6H11, PhCH2, c-C6H11CH2), of ortho- and para-substituted phenols (R = Et, Ph, c-C6H11, PhCH2) was studied by a batch method at 340 °C and 70 bar H2 over a sulfided NiOMoO3/γ-Al2O3 catalyst. The rates of hydrogenation are always higher for phenols than for benzenes and can be related to differences in the π-electron delocalization between the two series of organic compounds. The rates of hydrogenation of ortho- and para-substituted phenols are similar to one another and generally lower than those for phenol alone, thus suggesting a predominant role of electronic factors over steric ones.