Synchrotron SAXS/WAXD and rheological studies of clay suspensions in silicone fluid

Suspensions of two commercial smectite clays, montmorillonite KSF and montmorillonite K10, in a low-viscosity silicone oil (Dow Corning 245 Fluid) were studied by simultaneous synchrotron small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) techniques and rheological measurements. In the 0.5% (w/v) KSF clay suspension and two K10 clay suspensions (0.5% and 1.0%), WAXD profiles below 2theta=10.0 degrees did not display any characteristic reflection peaks associated with the chosen montmorillonite clays, while corresponding SAXS profiles exhibited distinct scattering maxima, indicating that both clays were delaminated by the silicone oil. In spite of the large increase in viscosity, the clay suspensions exhibited no gel characteristics. Dynamic rheological experiments indicated that the clay/silicone oil suspensions exhibited the behavior of viscoelasticity, which could be influenced by the type and the concentration of the clay. For the K10 clay suspensions, the frequency-dependent loss modulus (G") was greater in magnitude than the storage modulus (G') in the concentration range from 0.5 to 12.0%. The increase in the clay concentration shifted the crossover point between G' and G" into the accessible frequency range, indicating that the system became more elastic. In contrast, the KSF clay suspension exhibited lower G' and G" values, indicating a weaker viscoelastic response. The larger viscoelasticity response in the K10 clay suspension may be due to the acid treatment generating a higher concentration of silanol groups on the clay surface.     

Novel mild synthesis of high-added-value p-hydroxyphenyl acetic acid and 3,4-dihydroxyphenyl acetic acid using the acidic clay/hydrogen peroxide catalytic system

Acid-activated clays KSF and KSF/0 were successfully used in the hydrogen peroxide conversion of phenyl acetic acid to high-added phenolic compounds: p-hydroxyphenyl acetic acid and 3,4-dihydroxyphenyl acetic acid, endowed with a powerful antioxidant capacity. The catalytic conversion enhancement could be correlated to the total surface acidity and the high iron content of the catalysts KSF/0 and KSF, respectively. The synthetic route described here was conducted under mild conditions with very low degree of mineralization and without significant Fe ion leaching observations. The synthesis reaction is operationally simple and could find application for industrial purposes.     

A green and selective synthesis of 2‐aryloxazines and 2‐aryltetrahydropyrimidines

An efficient method for the selective synthesis of 2‐substituted oxazines and tetrahydropyrimidines by the reaction of arylnitriles with 3‐amino‐1‐propanol and 1,3‐diaminopropane in the presence of montmorillonite K‐10 and KSF as inexpensive, environmentally benign, and reusable catalysts under classical heating conditions and microwave irradiation is reported. J. Heterocyclic Chem., (2011).     

Montmorillonite clay-catalyzed cyclotrimerization and oxidation of aliphatic aldehydes

A temperature-dependent equilibrium is observed for the cyclotrimerization of aliphatic aldehydes in the presence of Montmorillonite K10 clay, while aerobic oxidation of aliphatic aldehydes to the corresponding carboxylic acids is favored at room temperature in the presence of Montmorillonite KSF clay.     

Catalyzed Knoevenagel reactions on inorganic solid supports: Application to the synthesis of coumarine compounds

Knoevenagel reactions involving carbonyl compounds and active methylene derivatives have been studied in the presence of alumina, KSF and K10 montmorillonites. With addition of water the ester group undergoes hydrolysis. A route is disclosed for the synthesis of coumarine compounds catalyzed by solid supports.     

Investigation of the Montmorillonite clay-catalyzed [1,3] shift reaction of 3-methyl-2-butenyl phenyl ether

The [1,3] shift reaction of 3-methyl-2-butenyl phenyl ether was catalyzed more effectively by Montmorillonite K10 clay than Montmorillonite KSF clay, and proceeded with greatest ortho-selectivity in carbon tetrachloride at room temperature.     

Development of antimicrobial cotton fabric using bionanocomposites

In order to provide antimicrobial activity to cotton, cotton fabrics were treated by montmorillonite (KSF), montmorillonite–dihydroxy ethylene urea (KSF–MDEU), KSF–chitosan (CS) and KSF–CS–MDEU solutions containing 12.5, 25 and 50 ppm silver ion. The effect of modification on the antibacterial activity of cotton fabrics was also evaluated after 10 cycles of washings. MDEU exhibited better antimicrobial activities after washing process. By using 25 ppm silver, KSF and CS modification solution, good performance in terms of antibacterial activity was obtained. The addition of CS and MDEU increased the whiteness index values of cotton fabrics treated with KSF containing different silver concentrations. The characterization of modified cotton samples was done by Fourier transform infrared spectroscopy, X-ray diffraction analysis, inductively coupled plasma-mass spectroscopy, scanning electron microscopy and thermogravimetric analysis.     

One‐Pot Synthesis of Nitriles from Aldehydes and Hydroxylamine Hydrochloride over Silica Gel,Montmorillonites K‐10, and KSF Catalysts in Dry Media Under Microwave Irradiation

Abstract

A rapid and facile one‐pot synthesis of nitriles has been carried out from the corresponding aldehydes and hydroxylamine hydrochloride in the presence of environmentally benign silica gel (84–95%), Mont K‐10 (85–96%), and Mont KSF clay (88–98%) catalysts in dry media under microwave irradiation.     

Prenylation of 4-Methylphenol

Russian Journal of General Chemistry - Organoaluminum (aluminum phenolate and aluminum isopropylate) and acidic heterogeneous catalysts (zeolites C-10, C-100 and ZSM, clay KSF, sulfonic cation...     

Absorption spectroscopic investigations on M[Al (OC3H7i)4]3 (M = Pr, Nd) - catalysed reduction of ketones

Transition metal (Mo, V and Cr) incorporated montmorillonite KSF and K10, catalyzed the liquid phase benzylation of o-xylene by benzyl chloride efficiently with high selectivity towards monoalkylated product. Mo catalysts showed the highest catalytic activities. The catalysts were characterized by XRD, surface area, pore volume and acidity measurements and by temperature programmed desorption of ammonia.This revised version was published online in December 2005 with corrections to the Cover Date.     

Microwave-Induced Solvent-free Synthesis of β-Keto Esters Using Montmorillonite KSF and K10 Clays as Efficient and Recyclable Heterogeneous Solid Acids

Montmorillonite KSF and K10 clays catalyzed effectively the reaction of methyl diazoacetate with various aldehydes using microwave irradiation under solvent-free conditions affording the corresponding β-keto esters in good yields and short reaction time. The present method is an improvement for the previous known synthetic methods and has many obvious advantages compared to them including the high efficiency, generality, high yields, operational simplicity, environmental benignity, and possibility of recycling the natural solid clays.     

KSF supported 10-molybdo-2-vanadophosphoric acid as an efficient and reusable catalyst for one-pot synthesis of 2,4,5-trisubstituted imidazole derivatives under solvent-free condition

The one-pot three-component cyclocondensation has been developed involving the reaction of benzil with an aromatic aldehydes and ammonium acetate under thermal solvent-free conditions in the presence of a KSF supported 10-molybdo-2-vanadophosphoric acid catalyst. 10-Molybdo-2-vanadophosphoric acid was immobilized on KSF with a 20% loading, which showed the highest catalytic activity. The catalyst was fully characterized using FT-IR spectroscopy, thermal analysis, XRD and SEM analysis techniques. There are several distinct advantages to this protocol, including high yields, short reaction time, operational simplicity and a recyclable catalyst with a facile work-up procedure.     

Nitration of phenolic compounds by metal-modified montmorillonite KSF

The nitration of phenolic compounds with 60% nitric acid (1.2 equiv) has been carried out in the presence of metal-modified montmorillonite KSF, prepared from different metals (V, Mo, W; Sc, La, Yb, Eu, In, Bi, Ti, Zr, Hf) and KSF or nitric acid treated HKSF, as catalysts. These catalysts showed good stabilities and high catalytic activities in nitration process. In addition, these catalysts can be recovered easily and reused for many times in nitration. This process is an eco-safer and environment-benign way for clean synthesis of nitrated phenolic compounds.     

无溶剂条件下以10-钼-2-钒磷酸为高效、可重复使用催化剂一锅法合成2,4,5-三取代咪唑衍生物（英文）

The one-pot three-component cyclocondensation has been developed involving the reaction of benzil with an aromatic aldehydes and ammonium acetate under thermal solvent-free conditions in the presence of a KSF supported 10-molybdo-2-vanadophosphoric acid catalyst. 10-Molybdo-2-vanadophosphoric acid was immobilized on KSF with a 20% loading, which showed the highest catalytic activity. The catalyst was fully characterized using FT-IR spectroscopy, thermal analysis, XRD and SEM analysis techniques. There are several distinct advantages to this protocol, including high yields, short reaction time, operational simplicity and a recyclable catalyst with a facile work-up procedure.     

Degradation of Orange II by heterogeneous photocatalytic reaction using montmorillonite KSF

Degradation of Orange II in montmorillonite KSF (KSF) suspensions under irradiation by a 250 W metal halide lamp (λ ≥ 365 nm) was investigated. The degradation kinetics of Orange II in KSF suspensions followed the Langmuir-Hinshelwood model. The effects of KSF concentration, solution pH, initial Orange II concentration, carboxylic salts were studied.     

Spectroscopic Studies on the Interaction of Tetramethylpyridylporphyrins and Cationic Clays

In the present work, the interaction between5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) and its metallated form(CoTMPyP) with three cationic clays was investigatedby X-ray diffraction (XRD), UV-VIS and resonance Ramanspectroscopies. Sodium montmorillonites K10 and KSFand a synthetic fluorohectorite (FHT) containingdifferent macrocycle loadings, were prepared by an ionexchange reaction. In nonsaturated KSF and FHT, theCoTMPyP molecule assumes a flat orientation, relativeto the host layers, giving rise to at least twoabsorption bands in the Soret region (ca. 445 and 465 nm)assigned to adsorbed and intercalated CoTMPyP,respectively. For the delaminated K10 sample, a broadband centered around 456 nm, indicates a majorcontribution from the metalloporphyrin on the clayexternal surfaces. The electronic spectra of FHTsamples containing increasing amounts of CoTMPyPshow bands red shifted even when a small amount ofporphyrin is used, suggesting that the electroniclevels of the macrocycle are more affected by theinteraction with the clay than by the metalloporphyrindistortion inside the galleries. The resonance Ramanspectra obtained for all CoTMPyP samples presentedonly minor shifts in peak positions and band width,with the exception of the FHT saturated sample, wherethe bands are clearly broader when compared to otherloadings, suggesting that porphyrin aggregation isoccurring. In the case of TMPyP, the bands at ca. 430and 468 nm were assigned to nonprotonated andprotonated molecules, respectively. This assignment issupported by resonance Raman spectroscopy, which alsoshowed the ₂ mode (ca. 1550 cm^-1) to bethe most sensitive peak to protonation.     

Clay Catalysis: Synthesis of Organosulphur Synthons

Abstract

The Montmorillonite KSF catalyses the synthesis of a large variety of organic sulphur compounds from carbonyl compounds: dithianes, thioacetals, thioketals, thiochromanes.

Clay minerals are known to cataiyse a variety of organic reactions(1). In these reaction, the clay catalyst acts as a solid Bronsted acid. One of the most acidic, Montmorillonite manufactured by Sud Chemie, is the KSF catalyst. Clay is inexpensive and offers several advantages to the classic acid: a strong acidity (Ho = ?8 to ?9), no corrosive action, selectivity and easy work-up.

We report here, that KSF clay is a convenient catalyst for the synthesis of useful thio-organic reagents : dithianes, thioketals, trithioorthoformiates, thiochromanes. The condensations of the thiol with the carbonyl compounds were completed in refluxing toluene in presence of KSF with the azeotropic separation of water. Generally the pure compound was obtained in these reactions and the work-up very simple.     

Adsorption of Promethazine hydrochloride with KSF Montmorillonite

Adsorption of Promethazine hydrochloride (PHCl) onto KSF Montmorillonite from aqueous solution has been investigated. Experiments were conducted at various pH values, ionic backgrounds and solution temperatures. The pseudo-second-order equation successfully predicted the adsorption among the tried kinetics models (pseudo-first-order, pseudo-second-order and intraparticle diffusion). Langmuir, Freundlich and DR adsorption models were used to describe equilibrium isotherms and the isotherm constants were obtained. The increase in solution temperature caused a decrease in the adsorption capacity values found from Freundlich and DR isotherm. The adsorption type can be explained by combined ion exchange and physisorption. Thermodynamic parameters of adsorption of Promethazine hydrochloride (PHCl) onto KSF were also evaluated. The surface morphologies of KSF and PHCl loaded KSF were examined using a scanning electron microscope (SEM). FTIR measurements of samples were also conducted.     

Clay Catalysis: Dry Condensation of 3-Methyl-1- Phenyl-5-Pyrazolone with Aldehydes Under Microwave Irradiation

3-Methyl-1-phenyl -5-pyrazolone (1) and arylcarboxyaldehydes (2) were condensated to 1-phenyl-3-methyl-4-(arylmethylene)-5-pyrazolone (3) in presence of acidic clay KSF without solvent under microwave irradiation.     

Microwave-assisted rapid cyclization of lapachol, a main constituent of Heterophragma adenophyllum

Cyclization reactions of lapachol (1) isolated from Heterophragma adenophyllum have been studied under microwave irradiation under different conditions using alumina (acidic, basic and neutral)/silica gel/montmorillonite (KSF and K-10) as solid support along with neat reaction using 2-3 drops of DMF giving naturally occurring dehydro-alpha-lapachone (2), alpha-lapachone (3), beta-lapachone (4) depending upon the nature of support and irradiation time. A novel naphthoquinone derivative adenophyllone (5) can be synthesized from lapachol using DMF under microwaves.