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With the overview of different kinds of phenol synthesis routes, dehydrogenation of cyclohexanone to phenol under sub-critical water condition using Pt, Pd, Rh, Ru and Re immobilized heterogeneous catalysts have been reported. Surface properties and characterizations of the catalysts were done. Binding of metal on a support and their relationship with zeta potential (ζ) and their effect on catalytic activity are discussed. Importance of sub-critical water reaction conditions in terms of thermodynamic favourability and phase equilibrium are evaluated through ASPEN simulator. Based on the results obtained, possible reaction pathways for the formation of product and the by-products are illustrated. The feasibility of a metal acting as a dehydrogenation catalyst according to M0/MII (E0) couple is also explained.

Ni-nanoparticle supported on mesoporous ZSM-5 was prepared by dispersing colloidal Ni-nanoparticle over mesoporous ZSM-5. The resulting material was found thermally stable even at 900 °C and has uniform pore diameter of around 5 nm. The material was characterized by XRD, FE-SEM, TEM, XPS, TPR and N 2 adsorption/desorption. Reforming of methane with CO 2 was performed over Ni supported on mesoporous ZSM-5 at atmospheric pressure. The catalyst shows 96.2% methane conversion at 800 °C with the production of synthetic gas with the H 2 /CO mole ratio of 1:1. Various reaction parameters like temperature, weight hour space velocity (WHSV), Ni loading and time on stream were also studied.

A variety of multivalent metal salt, many of them are hydrates, were screened as catalysts for the esterification of fatty acids and alcohols. These salts included chlorides, nitrates, sulfates, and acetates of Fe3+, Al3+, Ga3+, In3+, ZrO2+, HfO2+, Zn2+, Co2+, Ni2+, Mn3+, Cr3+, and Cu2+. Ferric salts, particularly, FeCl3·6H2O, were the most active among the salts screened. The esters of primary C10−C18 fatty acids and alcohols were obtained quantitatively from equimolar mixtures in the presence of FeCl3·6H2O (substrate/catalyst (S/C; mol/mol) = 200, reaction period = 6 h, in refluxing mesitylene). Esters of isostearic acid and C10–C18 fatty alcohols were obtained with large quantities and prolonged reaction periods. The esters of aromatic carboxylic acids with cetyl alcohol and bulky steroid alcohols, including cholesterol, with C8−C18 fatty acids, were obtained in high yield. The cationic cluster formed by hydrolysis of the ferric cation is proposed to be the catalytically active species. Such a catalysi...

Samples of small-pore Engelhard titanium silicate ETS-4 and its Sr-exchanged variant, patented by Engelhard Corporation, were successfully synthesized in our laboratory, and the characteristic signatures of their crystal structures were confirmed by X-ray diffraction (XRD). Thermogravimetric analysis (TGA) was carried out to study their thermal behavior and stability, and crystal morphology was examined using a scanning electron microscope (SEM). The synthesized fine crystals were pelletized by pressure binding without the addition of any binder material. Equilibrium and uptake measurements for oxygen, nitrogen, and methane on Na- and Sr-exchanged ETS-4 were then carried out in a constant-volume apparatus. The equilibrium capacities of the three gases in the Na form of ETS-4 were comparable, and Sr exchange did not seem to significantly affect these capacities. However, Sr exchange appreciably increased the uptake rate of nitrogen and reduced that of methane, thereby increasing the kinetic selectivity to a promising level. Capacity and uptake measurements were also conducted on the Sr-exchanged ETS-4 dehydrated at different temperatures. It was observed that increasing dehydration temperature progressively lowered the capacities and also slowed the kinetics of adsorption. Probable reasons for the observed changes in equilibrium capacity and uptake are discussed in detail.

A liquid phase reaction between anhydrous AlCl3 and terminal Si–OH groups of mesoporous Si-MCM-41 in dry CCl4 results in a AlClx-grafted Si-MCM-41 (with Cl/Al ratio=1.43, Al(tetrahedral)/Al(octahedral)=ratio=0.84 and Al/Si ratio=0.17). This catalyst shows high catalytic activity in Friedel–Crafts type benzylation (by benzyl chloride) and acylation (by benzoyl chloride) of benzene and toluene.

Thermal activation of clayzic catalyst has been thoroughly investigated by calcining anhydrous ZnCl2 impregnated on Mont-K10 with different ZnCl2 loadings (0.5-2.0 mmol g-1) under static or flowing air at 270 °C and also under N2 flow at different temperatures (150-400 °C). Depending upon the ZnCl2 loading and calcination temperatures, an appreciable amount of HCl is evolved in the thermal activation, indicating an occurrence of reaction between the ZnCl2 and the surface hydroxyl groups of the clay (- OH + ZnCl2→ - O - Zn - Cl + HCl), leading to formation of new Lewis acid sites (- O - Zn -Cl). The Cl/Zn ratio, surface area and catalytic activity (in the benzene benzylation by benzyl chloride at 80 °C) of the clayzic formed in the thermal activation are influenced markedly by the ZnCl2 loading and calcination conditions (temperature and gas atmosphere). The maximum catalytic activity for the clayzic is observed at the optimum ZnCl2 loading (about 1.0 mmol g-1) and calcination temperature (about 270 °C). The thermal activation at 270 °C under flowing N2 led to a most active clayzic catalyst for the benzene benzylation. A temperature-programmed evolution of HCl in the calcination of ZnCl2/Mont-K10 with different ZnCl2 loadings from 25 to 400 °C at a linear heating rate of 2 °C min-1 has also been investigated.

Si-MCM-41 supported InCl3, GaCl3, FeCl3 and ZnCl2 catalysts (metal chloride loading = 1.1 mmol g −1 ) have very small activity for the dehydration of tert-butanol and hence show very high selectivity (>99%) for the esterification of tert-butanol by acetic anhydride, producing acetic acid as a by-product, at ⩽50°C. The esterification activity of the supported metal chloride catalysts is in the following order: InCl3> GaCl3> ZnCl2> FeCl3.

Adsorption properties of the mesoporous H–AlSi–MCM-41 and Na–AlSi–MCM-41 materials for aromatic hydrocarbons have been investigated by studying the temperature programmed desorption (TPD) of toluene, p-xylene, mesitylene and naphthalene over the mesoporous materials from 323 to 673 K at different linear heating rates (5–25 K min−1). The toluene TPD spectra show three distinct peaks for the H–AlSi–MCM-41 but a single asymmetric peak with humps for the Na–AlSi–MCM-41. The TPD spectra of all the other aromatic hydrocarbons for both the adsorbents show a single asymmetric peak with humps. The order of the heat of adsorption for the aromatic hydrocarbons, estimated from the temperature dependence of their peak (first one) maximum temperature was found as follows: toluene

Clay (kaolin, mont-K10 and mont-KSF) supported InCl 3 , GaCl 3 , FeCl 3 and ZnCl 2 catalysts (metal chloride loading=1.1 mmol g −1 ) show high selectivity (⩾98%) at high conversion in the esterification of tert-butanol by acetic anhydride to tert-butyl acetate ( t -BA) and very low activity for the dehydration of tert-butanol at ⩽50°C. For all the catalysts, mont-K10 is the best support and the order of their esterification activity (at 26°C) is: InCl 3 /mont-K10 (TOF=0.025 s −1 ) > GaCl 3 /mont-K10 (0.023 s −1 ) > FeCl 3 /mont-K10 (0.02 s −1 ) ⩾ ZnCl 2 /mont-K10 (0.019 s −1 ). InCl 3 /mont-K10 is highly active, selective and reusable catalyst for the esterification.

Temperature programmed desorption (TPD) of aromatic hydrocarbons (viz. toluene, p -xylene, mesitylene and naphthalene) on mesoporous high silica MCM-41 from 323 to 673 K at different linear heating rates (5, 10, 15 and 25 K min −1 ) has been investigated. TPD of toluene at different adsorbate loading (0.5 to 16.3 μmol g −1 ) has also been investigated. All the TPD curves have a single asymmetric peak. The heats of adsorption of aromatic hydrocarbons on the mesoporous material, estimated from the TPD peak maximum temperatures measured at different heating rates, was found to occur in the following order: toluene p -xylene H a increases with the decrease in the ionization potential of the hydrocarbons. The adsorption results from weak interactions between the π-electrons of aromatic hydrocarbons and the terminal poorly acidic silanol (Si–OH) groups. In the case of toluene TPD, the TPD peak maximum temperature increases with decreasing the adsorbate loading, indicating the presence of site energy distribution on the high silica MCM-41.

The influence of zeolite factors, such as Ga loading (0–3%), Si/Al ratio (35–132), degree of H + exchange (2–98%) and calcination temperature (600–800°C), affecting zeolitic acidity on the activity and selectivity of Ga/H–ZSM-5 in the aromatization of propane has been investigated. The activity and selectivity in propane-to-aromatics conversion are found to be influenced strongly by the above zeolite factors. The aromatization activity and selectivity of the zeolite shows a close relationship with its strong acidity (measured in terms of pyridine chemisorbed at 400°C). The propane aromatization activity and selectivity increases sharply with the increase in the strong acid sites of the Ga/H–ZSM-5.

The acidity and initial and time-on-stream activity in propane aromatization (at 550°C, space velocity of 3100 cm3g−1(zeolite)h−1) of Ga-impregnated H-ZSM-5 zeolite without or with binders (50 wt%), such as silica, alumina and kaolin, have been investigated. Both the acidity and catalytic activity of the zeolite are influenced by the presence of binder in the catalyst, depending upon the binder. The influence is found to be lowest for alumina and highest for kaolin. Among the binders, alumina is the most preferred binder for the zeolite catalyst.

Some typical multi-valent metal salts, such as chloride, nitrate, sulfate, and acetate of Fe(III), Al(III), Ga(III), In(III), Zr(IV), Hf(IV), Zn(II), Co(II), Ni(II), Mn(III), Cr(III), and Cu(II) ha...