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One of the most dramatic effects of vibrational and chemical non-equilibrium in hypersonic flows occurs in the bow-shock detachment process in flow over a wedge. This was shown theoretically and in reflected shock tunnel experiments by Hornung & Smith (J. Fluid Mech., vol. 93, 1979, pp. 225–239). In the present work, the effect is first demonstrated by computation of two-dimensional non-equilibrium flows. The effect of the finite transverse extent of the wedge is then studied by three-dimensional computations of non-relaxing flows. An analytical formula is obtained that gives the shock detachment distance of a finite wedge for ideal-gas and equilibrium flows. In the experiment, the finite transverse extent of the wedge competes with the non-equilibrium effects, as each introduces a new length scale. The carbon dioxide and nitrogen flows of the experiment are therefore computed in three dimensions and with two-temperature chemistry accounting for vibrational and chemical non-equilibrium. In the case of nitrogen flow, the agreement between experiment and computation is not good, the experimental detachment distance being larger. A number of possible reasons are quantitatively examined. A conclusive resolution of the discrepancy is considered to require a repeat of the experiment with more accurately characterized conditions. In the case of the carbon dioxide experiments, the computed results agree remarkably well with experiment. This is partially due to the fact that the condition is very close to equilibrium, where the sensitivity of the detachment process to relaxation effects is small. The analytical expression for the dimensionless detachment distance agrees very well with all the three-dimensional computations of non-relaxing flows.

© The Royal Society of Chemistry 2016. Pt/ZSM-5 catalysts with various crystal sizes were prepared via competitive ion-exchange, followed by a slow activation procedure. Even when using very large ZSM-5 crystals, highly dispersed Pt nano-clusters were contained within the zeolite crystal's voids, as ascertained by 2D pressure-jump IR spectroscopy of adsorbed CO and focussed ion-beam transmission electron microscopy. The shape-selective properties of the Pt/ZSM-5 catalysts were evaluated in the partial hydrogenation of soybean oil. Unique hydrogenation selectivities were observed, as the fatty acids located at the central position of the triacylglycerol (TAG) molecules were preferentially hydrogenated. The resulting oil has therefore high levels of intermediately melting TAGs, which are compatible with biolubricants due to their improved oxidative stability and still appropriate low-temperature fluidity. The TAG distribution in the partially hydrogenated soybean oil samples was independent from the zeolite crystal size, while the hydrogenation activity linearly increases with the crystal's external surface area. This trend was confirmed with a Pt loaded mesoporous ZSM-5 zeolite, obtained via a mild alkaline treatment. These observations imply and confirm a genuine pore mouth catalysis mechanism, in which only one fatty acid chain of the TAG is able to enter the micropores of ZSM-5, where the double bonds are hydrogenated by the crystal encapsulated Pt-clusters. crosscheck: This document is CrossCheck deposited related_data: Supplementary Information copyright_licence: The Royal Society of Chemistry has an exclusive publication licence for this journal copyright_licence: This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0) history: Received 4 March 2016; Accepted 30 March 2016; Accepted Manuscript published 31 March 2016; Advance Article published 13 April 2016; Version of Record published 18 April 2016 ispartof: Catalysis Science & Technology vol:6 issue:8 pages:2820-2828 status: published

This work presents a new carbon–silica hybrid material, denoted as CSM, with remarkable sorption properties. It consists of intraporous graphitic nanocrystals grown in the pores of mesoporous silica. CSM is obtained by a subtle incipient wetness impregnation of Al-containing mesoporous silica with furfuryl alcohol (FA)/hemelitol solutions. Both the volume match of the impregnation solution with that of the silica template pore volume, and the presence of Al3+ in the silica, are crucial to polymerize FA selectively inside the mesopores. Carbonization of the intraporous polymer was then performed by pyrolysis under He up to 1273 K. The resulting CSMs were examined by SEM, HRTEM, 27Al MAS NMR, N2 adsorption, XRD, TGA, TPD, XPS, pycnometry and Raman spectroscopy. Mildly oxidized graphitic-like carbon nanoblocks, consisting of a few graphene-like sheets, were thus identified inside the template mesopores. Random stacking of these carbon crystallites generates microporosity resulting in biporous materials at low carbon content and microporous materials at high carbon loadings. Very narrow pore distributions were obtained when pyrolysis was carried out under slow heating rate, viz. 1 K min−1. Adsorption and shape selective properties of the carbon filled mesoporous silica were studied by performing pulse chromatography and breakthrough experiments, and by measuring adsorption isotherms of linear and branched alkanes. Whereas the parent mesoporous silica shows unselective adsorption, their CSM analogues preferentially adsorb linear alkanes. The sorption capacity and selectivity can be adjusted by changing the pore size of the template or by varying the synthesis conditions. A relation between the carbon crystallites’ size and the shape selective behaviour of the corresponding CSM for instance is demonstrated. Most interestingly, CSM shows separation factors for linear and branched alkanes up to values comparable to those of zeolitic molecular sieves.

We here present the controlled synthesis of ultra-small diameter nanotubes in well-defined subnanometer sized confined space within zeolites. A critical view on the zeolite occluded nanotube growth is presented. Thermogravimetric analysis and optical techniques are evaluated for nanotube characterization. The introduction of Bro̸nsted acid sites in the zeolite framework leads to optimized yields. As temperatures below 500{degree sign}C are envisioned for nanotube synthesis, zeolite occluded nanotubes are compatible with current CMOS technology platform, in densities in accordance with ITRS standards for future interconnects, making zeolites a viable pathway for integration of SWCNTs in the chip of the future.

This study examined the solving of a visual-spatial reasoning puzzle task by children. The goal of the experiment was to measure how the physical form in which an educational task was presented influenced children’s task performance. All children were administered two sets of randomly chosen puzzle tasks. The order in which the task format was presented differed: children in condition one were presented tangible puzzle tasks first; in the second condition tasks in a virtual format were presented first. We compared the task performances of 26 children aged 5–7 in both conditions. The results show that, independent of the order of the task format, task completion times for the tangible version were significantly shorter than those for the virtual version. In addition, we found that children engaged in far more overt problem solving behaviour when using the tangible version; this most likely helped them to find the correct solution quicker. These findings support our hypothesis that tangible interfaces are more appropriate for training visual-spatial reasoning in this age group than are their screen-based virtual counterparts. The latter may require additional, underlying skills to operate the interface. Indeed, the results suggest that, for the virtual format, the variations in the task completion times between task types can be attributed to the number of puzzle piece rotations required.

A unified model for the description of vapor- and liquid-phase hydroconversion has been developed. The high isomer yield, which is typical for the shape selectivity exhibited by Pt/H-ZSM-22 at vapor-phase conditions, is still observed at liquid-phase conditions. However, the molar cracking yield is enhanced by at least 10 mol % when operating at liquid-phase conditions. The latter effect is mainly due to an increased physisorption competitiveness of lighter alkanes, which also results in enhanced cracking of lighter alkanes. The effect amounts to approximately 3 orders of magnitude for a difference of 2 in carbon number. These aggregation state effects are accounted for in the model through (i) liquid phase thermodynamic nonideality, (ii) destabilization of the physisorbed state by compression of the adsorbate by the bulk fluid, and (iii) carbenium ion stabilization by sorbent solvation by the bulk fluid. F-values of the order of 103 indicate the model's adequacy in describing the observed phenomena.

New model catalysts were prepared by applying DC magnetron sputter deposition of vanadia onto ZrO 2 /SiO 2 and TiO 2 /ZrO 2 /SiO 2 supports and were characterized by X-ray diffraction (XRD), X-ray energy dispersive spectrometry (EDX), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma emission spectroscopy (ICP) and catalytic activity towards propane and isobutane oxidative dehydrogenation. Titania interlayer enhances oxidative dehydrogenation activity and decreases the total oxidation side reactions. A Mars–van Krevelen mechanism is operative.

The detection of a low level 45,X cell line during routine cytogenetic analysis in an adult female can be difficult to interpret. In the absence of recent information regarding loss of the X chromosome and ageing, we undertook a prospective study. A total of 19,650 cells from 655 females aged from birth to 80 years were screened cytogenetically. The frequency of X chromosome loss ranged from 0.07% at age 65 years of age and showed a highly significant quadratic relationship between X chromosome loss and ageing (P ≤ 0.00001). We have produced a graphic representation that provides a minimum baseline age-related rate of X chromosome loss. This should assist diagnostic cytogenetics laboratories to determine the significance of 45,X cell lines detected in women of all ages. We also compared the frequency of 45,X cells in women referred with at least one spontaneous abortion with those referred for other reasons and found no significant difference. Thus, in our population, an excess of 45,X cells is not associated with pregnancy loss.

Model vanadia catalysts were synthesised using magnetron sputtering of the active species for precisely controlled and clean catalyst design. Two series of supported vanadia catalysts were produced on inert beads with silica surface: vanadia/silica through single vanadia coating and vanadia/titania/silica by subsequent deposition of titania and vanadia. Loadings were varied by changing deposition time. All catalysts were characterised for structure and reducibility. Catalytic performance was tested by steady-state and transient experiments with propane oxidative dehydrogenation. Both supports yielded similar vanadia structures and equal dispersion. The vanadia loading strongly influenced structure and chemical behaviour. Shorter depositions gave surface vanadia monomers and polymers, whereas for longer depositions, crystalline species developed on either support. In propane oxidative dehydrogenation, very high turnover frequencies were obtained, especially for thinner depositions. An intermediate titania layer strongly influenced the vanadia activity. Maximum activity was obtained for a few vanadia layers supported on titania. (c) 2006 Elsevier Inc. All rights reserved.

Silica sol–gel immobilized triflate compounds like La(OTf) 3 , tert -butyldimethylsilyl trifluoromethanesulfonate (BDMST) and triflic acid (HOTf) were tested in the acylation of 2-methoxynaphthalene with acetic anhydride, leading to 1-acetyl-2-methoxynaphthalene as the major product. The reaction only proceeded with good yields on BDMST and HOTf catalysts, while La(OTf) 3 presented a low activity. For BDMST in solvent-free conditions, the resulting TOF was superior to that reported in literature for other heterogeneous catalysts and even for homogeneous triflates. The rates of reactions in various solvents strongly depend on the donor number of these solvents.

A relumped single-event microkinetic (SEMK) model is developed to describe alkane hydroconversion on shape-selective Pt-H/ZSM-22. The model, considers n -alkane, mono-, di- and tri-branched alkanes for each carbon number and is developed according to the reaction rules formulated for the molecular SEMK model on ZSM-22. Differences in physisorption and protonation behaviour among the carbenium ions on ZSM-22 are accounted for. Reactions can occur at the pore mouth, bridge and micropore acid sites. Lumping coefficients depend on the type of sites. The calculation of the lumping coefficients is performed using a structural class based method, not requiring the generation of the detailed reaction network. The internal composition of a lump is determined by the physisorption properties of the alkanes belonging to the lump. The hydrocracking of n -C6 to n -C18 alkanes is described adequately over a wide range of conversions.

Several dyes that generate singlet molecular oxygen ( 1 O 2 ) were occluded in polydimethylsiloxane (PDMS). For the homogeneous dyes, this occlusion forms an easy way of heterogenization, whereas it improves the performance of dyes that are heterogenized already in molecular sieves. These systems were investigated for the singlet oxygenation of test substrates, such as 2,3-dimethyl-2-butene and 1-methyl-1-cyclohexene. The PDMS elastomer was selected for its transparent, hydrophobic and permeability characteristics. The elastomer is ‘wrapped’ around the sensitizing system and hence shields the dyes from polar components, such as water, and balances the sorption of solvents and reagents. This results in an enhanced oxygenate yield for water sensitive dyes. Finally, a new porphyrin, 5,15-(2,6-dichlorophenyl)-10,20-(4-allyloxyphenyl)porphyrin, was synthesized and chemically anchored to PDMS, resulting in a highly active heterogeneous singlet oxygen generating system.

A facile ‘one-pot’ synthesis for poly(γ-methyl-l-glutamate) (PMLG) membranes is reported. Despite having an α-helical secondary structure, as demonstrated via IR, these membranes did not show enantioselective behavior in pressure driven permeation of Trp. Therefore, the transesterification of PMLG with Igepal and Brij® 30 is introduced in a next step and the resulting polymers are characterized by means of IR and NMR. Supported membranes made from these materials show permselectivity towards d-Trp under a pressure gradient, but the enantiomeric excess of the permeate phase declines as a function of time. In order to realize a constant enantioselectivity, electrodialysis is demonstrated to be a suitable membrane process. Moreover, the obtained permeation rates of Ac-Trp are among the best ever reported for solid enantioselective membranes and approximate those realized with liquid membranes.

Isomerization and hydrocracking of a mixture of 1-cyclohexyloctane and dodecane were performed on Pt/H-ZSM-22 in a three-phase Robinson Mahoney reactor with complete internal mixing (T=523–543 K, P=7–8 MPa, H2/HC=5). The reaction products from 1-cyclohexyloctane were analyzed in detail and compared with those obtained in the absence of dodecane in a fixed-bed vapor-phase reactor (T=460 K, P=0.45 MPa, H2/HC=450). In the presence of dodecane, the main reaction pathway involved contraction of the six-membered ring to a five-membered ring with concomitant elongation of the octyl chain by one carbon. Subsequently, the nonyl chain underwent methyl branching at carbon positions far from the ring. Methyl branching rearrangements of the cyclohexane ring of 1-cyclohexyloctane were suppressed in the presence of dodecane. In the reaction product fraction of heptylmethylcyclohexanes, all cis–trans and positional isomers were formed except the 1,1′-heptylmethylcyclohexane isomer. The isomer distributions were explained with pore mouth and key–lock catalysis. Pt/H-ZSM-22 did not favor the paring reaction. The distribution of cracked products, and especially the abundant formation of alkylcyclopentanes, was in agreement with cracking through β-scission in the chain rather than by ring dealkylation typical of the paring reaction. Ring opening in 1-cyclohexyloctane and its isomers is a less important side reaction.

(Mg, Al)-layered double hydroxides (LDHs) with different Mg/Al ratios in the octahedral layer were prepared via the coprecipitation method and were exchanged with varying amounts of molybdate. The composition of the LDH supports and the state of the molybdate in these materials were studied with X-ray diffractometry, X-ray photoelectron spectroscopy and Raman. As was proven by NIR luminescence, aqueous H2O2 is converted at the surface of these catalysts into excited, singlet molecular dioxygen (1O2). The singlet dioxygen diffuses away from the 1O2 generating centers and can perform selective oxygenations, such as endoperoxidations of dienes, or hydroperoxidations of olefins. Catalyst composition and reaction conditions (temperature, solvent) have major effects on the catalyzed 1O2 generation and the subsequent substrate oxygenation. In order to maximize the efficiency of the H2O2 use and to limit the epoxidation side reaction, it is advisable to limit the amount of exchanged molybdate to ∼0.2 mmol per g and to use an LDH with Mg0.9Al0.1 composition in the octahedral layer. The latter material provides the optimum basicity for the catalytic activity of the exchanged molybdate.

Biporous carbonsilica materials (CSM) with molecular sieve properties and high sorption capacity were developed by synthesizing nano-sized carbon crystallites in the mesopores of Al-MCM-41.

Aim. The aim of the present series of studies was to investigate what motivates undergraduate students and how their motivation changes during their degree course. The present research investigated both subject specific and generic motivators by asking students what knowledge areas, skills and experiences were important to them. Sample. Study 1: 336 prospective and current undergraduate psychology students at a university in southern England. Study 2: 57 year one psychology students from a university in the north of England. Study 3: 30 undergraduate psychology students from the university used in Study 1. Method. The studies used a modified version of the Radford and Holdstock (1993) scale to assess students’ objectives in taking a degree programme, by rating the importance of knowledge areas, skills development and experiences. Study 1 used a cross-sectional design comparing responses of student by year of study. Study 2 compared responses of students in year one in Study 1 to students at a second university. Study 3 used a longitudinal design to investigate changes in values by year of study. Results. The findings suggest that there are two types of students: those who are motivated by the discipline itself and those who are motivated by the acquisition of more general skills and experiences. The perceived importance of many aspects declines over the three years of the degree, and seems especially low in year two. However, some aspects, notably research methodology, and some skills and experiences show marked increases in the final year. Conclusions. Current theories of educational motivation need to be extended to account for the difference between subject-related and generic motives.

A mixture of n -paraffins as well as a hydrotreated gasoil were hydrocracked over a Pt/ZSM-22 and a Pt/USY zeolite catalyst in a three phase reactor with complete internal mixing operated under industrially relevant conditions. The distribution of the isomerization products obtained from the n -paraffin mixture and the hydrotreated gasoil on Pt/ZSM-22 shows that pore-mouth and key–lock catalysis are operative, although the selective formation of branching at the end of the carbon chain is less pronounced. Ethylbranching is suppressed in liquid as well as vapor phase conditions. The cracked products obtained on Pt/ZSM-22 for both feedstocks contain a high amount of linear paraffins in comparison to the amount observed for hydrocracking on Pt/USY. This indicates that similar to vapor phase operations, the scission of the bond in the β position of the positively charged secondary carbon atom towards a new secondary carbenium ion (s,s β-scission) is also the dominant cracking mechanism for operations in liquid phase. The differences between vapor and liquid phase operations of Pt/ZSM-22 are attributed to differences in the adsorption modes of the molecules.

The liquid phase hydrocarbon oxidation is studied in a packed bed membrane reactor. A mathematical model is developed, reaction simulations are performed and interpreted using the conversion, organic peroxide efficiency and oxidation product separation factor. The influence of several process parameters, such as space time, overall membrane mass transfer coefficient and aqueous-organic phase distribution coefficient is investigated. A substantial increase in organic peroxide efficiency was observed in the packed bed membrane reactor configuration as compared to a conventional packed bed reactor.

The in situ synthesis of methylalumoxane (MAO) on the crystalline structure of heteropoly acids generates a highly active and weakly coordinating compound for the metallocene catalyst. The MAO-phase formed by the controlled hydrolysis of trimethylaluminum covers the Keggin unit of the heteropoly compound, as is verified with several spectroscopic techniques. The primary Keggin structure of the heteropoly compound is preserved and MAO-formation induces an intensive charge transfer in the VIS-region. 27 Al-NMR of alumoxo-phosphotungstate illustrates the reversible interaction of the Lewis acid Al of the anchored alumoxane with the bridging oxygen atoms of the phosphotungstate Keggin structure. The interaction of the alumoxo-heteropoly compound with an ansa-metallocene produces a highly active catalyst for the co-oligomerization of ethene and propene. The softness of the heteropoly compound combined with the pseudo-liquid phase formation of the alumoxo-heteropoly compounds exceeds the activity of the homogeneous system and the stability of the heterogeneous MAO-anchored materials. The composition of the Keggin structure determines the catalytic potential of the metallocene which is transformed in a temperature dependent oligomerization and a fluctuating alternation of monomer and comonomer. The molecular weight and the methyl branching of the oligomer molecules are designing tools for the physicochemical features of a synthetic lubricant. A comparable charge delocalization over each heteropoly compound results in a single-sited catalytic system inducing a small dispersity of oligomer products.

The anchoring of alumoxane, synthesized by the in situ hydrolysis of trimethylaluminum, on the internal pore walls of a mesoporous MCM-41 support generates a highly active and selective host for bis(cyclopentadienyl)zirconium dimethyl (Cp2Zr(CH3)2) in the oligomerization of propene. The regioselective preference of the immobilized metallocene is preserved and a typical Flory–Schulz distribution for the propene oligomers is obtained.

A general method to immobilise homogeneous catalysts and to improve the performance of heterogeneous catalysts is discussed. The method consists in embedding the catalysts in hydrophobic PDMS (polydimethylsiloxane)-membranes. Inspired on a complete structural mimic of cytochrome P-450 up to the level of the membrane, this technique gives superior properties to the membrane resident catalyst. The scope and limitations of this method are discussed by two examples of heterogeneous catalysts, i.e., FePc-Y (iron phthalocyanine zeolite Y) and [Mn(bpy) 2 ] 2+ -Y (manganese bis(bipyridyl) zeolite Y), and three examples of homogeneous complexes, i.e., FePc, Ru-binap ([2,2′-bis(diphenylphosphino-1,1′-binaphtyl]chloro( p -cymene)-ruthenium chloride) and the Jacobsen catalyst ( N,N′ -bis(3,5-di- tert -butylsalicylidene)-1,2-cyclohexane-diamine manganese chloride). Due to changed sorption in the zeolites, catalyst activity is enhanced and deactivation is suppressed. Furthermore, the membrane incorporation makes the use of a solvent redundant. For homogenous complexes, this procedure represents a general method for heterogenisation. Moreover, the technique opens new ways in the field of oxidation chemistry, where solvents are necessary to homogenise reagents which usually differ in polarity.

Although cellulosic biomass offers a promising alternative as an abundant renewable resource in the production of biofuels and platform chemicals, so far only a few studies have reported its aqueous-phase conversion into glucose or sugar alcohols using solid chemocatalysts. The principal reason is that these polymeric biomolecules with semi-crystalline structure cannot penetrate the pores of conventional heterogeneous chemocatalysts. New advances in the conversion of cellulose thus require the design of efficient multifunctional catalytic systems with sterically accessible acid and metal sites.

The isomerization and disproportionation of m-xylene has been performed over zeolite β samples with Si/Al ratios in the range from 11 to 42. The selectivity for isomerization versus disproportionation and the selectivities among the isomerization and disproportionation products are contrasted with the micropore structures proposed for zeolite β. The isomerization and disproportionation activity of zeolite β depend strongly on the aluminium content, decreasing with increasing framework aluminium content. Maximum activity is found for Si/Al ratios between 14 and 15, while the p/o selectivity remains constant.

Si-VPI-5 crystals containing Si atoms in Si(4Al) environments arc synthesized. The crystals contain occluded amine. It is protonated and neutralizes the residual negative lattice charges associated with the Si(4A1) sites. Calcined Si-VPI-5 is active in the isomerisation of decane and exhibits extra-large pore characteristics.

Titanium silicalites with different titanium contents were synthesized according to two hydrothermal procedures. The materials were subjected to physicochemical characterization and tested as catalysts for partial oxygenations by aqueous hydrogen peroxide. The role of isolated titanium, finely divided titanium dioxide and residual acidity in the catalytic behavior of titanium silicalites is discussed and a mechanistic model for the oxidation reactions is proposed.

Titanium silicalites synthesized via different procedures are tested in the oxidation of phenol, l-octene and n-hexane by aqueous H2O2. It is shown that the presence of titanyl groups, on which H2O2 is activated by formation of titanium peroxo complexes, is a prerequisite for oxygenation activity. Furthermore, in order to afford high selectivities, titanium silicalites should be free of impurities which cause acid catalyzed side reactions or H2O2 decomposition.

The article contains sections titled: 1. Introduction 2. Furfural 2.1. Properties 2.1.1. Physical Properties 2.1.2. Chemical Properties 2.2. Resources and Raw Materials 2.3. Production 2.3.1. Chemistry of Furfural Production 2.3.2. Production of Furfural 2.4. Uses and Economic Aspects 2.5. Quality Specifications, Transportation, Toxicology 3. Furfuryl Alcohol 3.1. Properties 3.1.1. Physical Properties 3.1.2. Chemical Properties 3.2. Resources and Raw Materials 3.3. Production 3.4. Uses and Economic Aspects 3.5. Quality Specifications, Transportation, Toxicology 4. Furan 4.1. Properties 4.2. Production 4.3. Uses, Economic Aspects, Transportation, Toxicology 5. Tetrahydrofurfuryl Alcohol 5.1. Properties 5.2 Production 5.3 Uses, Economic Aspects, Transportation, Toxicology 6. Furfurylamine and Tetrahydrofurfurylamine 7. Methylfuran and Methyltetrahydrofuran 8. Furoic acid This article discusses the properties, production, and industrial uses of furfural and compounds derived from furfural on a commercial basis. The only commercial route to furfural is acid-catalyzed digestion of pentosan sugars in biomass. Nowadays, furfural is the sole precursor for all compounds containing a furyl, furfuryl, furoyl, or furfurylidene radical in the chemical industry. Detailed information is given on the production, properties, and economical aspects of furfural [98-01-1] and furfuryl alcohol [98-00-0], and the most important specialty chemicals derived from furfural and furfuryl alcohol are summarized: furan [110-00-9], tetrahydrofurfuryl alcohol [97-99-4], 3,4-dihydro-2H-pyran [110-87-2], furfurylamine [617-89-0], tetrahydrofurfurylamine [4795-29-3], 2-methylfuran [534-22-5], 2-methyltetrahydrofuran [96-47-9], and furoic acid [88-14-2].

Vermiculite mineral has been pillared with aluminum-cerium hydroxyl solutions after hydrothermal treatment, prior to the pillaring process. The pillared clays exhibited an increase of the microporosity and acid properties respect to the natural clay. The catalytic and textural properties were investigated in the hydroisomerization of decane. The modified vermiculites were very active with respect to most of the pillared clays and the pore size closed to 10 and 12-ring zeolites. The products distributions from decane isomerization showed that their profile is comparable to that of active zeolites.

In situ characterization techniques directly relate the physicochemical properties of a catalyst to its catalytic activity, allowing a more rational catalyst design. As a result of the sensitivity and inherent limitations of each spectroscopic approach, several problems are still unaccounted for (e.g. pressure gap, materials gap and phase gap). These shortcomings can be solved by applying new spectroscopic techniques. Here fluorescence microscopy is used to directly monitor chemical reactions inside zeolite crystals. This technique images the catalytic activity with a high spatiotemporal resolution and sensitivity and thus allows locating the active zones throughout an individual catalyst crystal.

Objective: To investigate whether there is a difference in general practitioners’ attitudes towards CAM in the UK and Germany. Study design: A descriptive questionnaire was developed and sent to 97 GPs in the UK and 99 GPs in Germany. Results: The overall response rate was 68%. German GPs showed a (non-significant) overall more positive attitude towards CAM than did British GPs. British GPs made more referrals to complementary practitioners. The most popular CAM therapies that UK GPs referred their patients to were chiropractic treatment, acupuncture and osteopathy. German GPs referred their patients mainly to acupuncture treatment, chiropractic treatment and herbal medicine. A significantly higher number of German GPs reported having practised as a CAM practitioner before and having personally used CAM themselves. Seventy percent of British GPs and 76% of German GPs thought it is safe to prescribe complementary medicine and therapies to patients. Conclusion: There are small national differences in referring patients to various CAM modalities. Both nations have an overall positive attitude toward and a high interest in CAM. Lack of scientific evidence and information on training opportunities were important points that were continuously raised by GPs in both countries.

Publisher Summary This chapter discusses the interactions of titanium (Ti) molecular sieves with hydrogen peroxide (H 2 O 2 ) using near infrared luminescence spectroscopy to detect the characteristic 1270 nm emission of the short-lived excited singlet molecular oxygen ( 1 O 2 ). For all titanium molecular sieves tested, part of the H 2 O 2 is converted to 1 O 2 ; higher H 2 O 2 concentrations result in more singlet molecular oxygen; increasing titanium content of the molecular sieve does not result in more 1 O 2 production; and particularly the hydrophilic (Ti,Al)-β produces 1 O 2 at a high rate.

Publisher Summary This chapter discusses the selective adsorption of trans unsaturated fatty acid compounds in MFI-type zeolites. A zeolite structure that selectively adsorbs trans unsaturated fatty acid compounds in the presence of their cis unsaturated counterparts is selected among several topologies using a liquid-phase chromatographic study of the adsorption of oleic and elaidic acid methylester. The functioning of the present adsorbent is based on the restricted adsorption of the curved cis unsaturated compounds in the pores of highly siliceous MFI type zeolites while the straight trans isomers experience significantly less limitations. The present selectivity is retained when the complexity of the substrate molecules is gradually increased from methylesters to triacylglycerols.

Publisher Summary Catalytic conversion of hydrocarbons over crystalline microporous acidic aluminosilicate catalysts is applied in large petroleum refining processes including catalytic cracking, hydro cracking, isomerization, alkylation, and oligomerization. This chapter provides with a conceptual basis for rationalizing this acid zeolite based catalytic hydrocarbon conversion processes. It is recognized that the zeolite acid strength is more in line with conventional strong acids rather than with superacid. In order to explain the reactivity and the selectivity of the zeolite catalyst, it is insufficient to represent the zeolite catalyst by a proton, by analogy to homogeneous strong BrOnsted acids, without considering the chemical and physical interactions of the hydrocarbon molecules with the zeolite framework. The kinetics of the catalytic conversions are dominated by the strong physical adsorption of the molecules on the catalyst being unique to zeolites.

Publisher Summary This chapter discusses the colloid chemical properties of silicalite-1 nanoslabs. Nanoslabs have negative zeta potential and contain occluded and externally adsorbed tetrapropylammonium (TPA). At room temperature, the nanoslabs form physical aggregates that dissociate upon dilution. The formation of these reversible aggregates accelerates silicalite-1 synthesis upon heating. The influence on the crystallization of dilution with water or tetrapropylammonium hydroxide (TPAOH) solution and of salt addition may be attributed to the changes of the nanoslab mobility and of the nanoslab–nanoslab interfaces. The externally adsorbed TPA controls the formation of ordered chemical bonds between nanoslabs in contact and the subsequent crystal formation.