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Catalytic carbonyl-olefin metathesis has emerged as a new strategy for the direct formation of carbon–carbon double bonds. Successful approaches for ring-closing carbonyl-olefin metathesis exist, but limitations remain in accessing systems larger than 5-membered rings. Currently available strategies rely on Lewis acidic superelectrophiles as stronger catalysts, which require precious metal additives for their formation upon chloride abstraction from otherwise environmentally benign metal salts, such as FeCl3. Herein we report the development of a continuous flow reactor that overcomes this challenge and can access 6-membered rings using FeCl3 as the Lewis acid catalyst. The plug-flow reactor design is user friendly, benchtop amenable, and demonstrates up to 200x improved reaction efficiency over batch conditions. Computational investigations reveal that this transformation proceeds through an unprecedented bimolecular stepwise pathway via intermolecular proton transfer. These insights represent a significant advance for catalytic carbonyl–olefin metathesis and are expected to spur future developments in catalyst design and reaction scope.

Highly processable hydrogels loaded with active components for localised drug delivery and/or live cells for regenerative medicine are an attractive target for biotechnology research. We describe a single-pot precipitation polymerisation of poly (N-isopropylacrylamide) (pNIPAM) from the surface of dispersed Laponite® platelets in aqueous media above its lower critical solution temperature (LCST), yielding tightly packed pNIPAM globules that resist aggregation and can be maintained for long periods of time as a low viscosity colloidal suspension. Upon cooling, the pNIPAM chains transform from the ‘globule’ to the ‘coil’ conformation, establishing multiple physical interactions and chain entanglement leading to irreversible gel formation. We have shown that the temperature and rate of phase transition and the rheological and mechanical properties of Laponite®-pNIPAM hydrogel can be tailored by addition of N, N′-dimethylacrylamide (DMAc) comonomer and other biologically relevant additives. The tuneable properties of Laponite®-pNIPAM hydrogel confirms its excellent potential for a wide range of therapeutic applications.

Background and Aims: Nasal glucagon is a ready-to-use, drug-device combination therapy for the treatment of severe hypoglycemia. Portability is key, as nasal glucagon should be carried by persons with diabetes at all times. In designing for portability, the medication must allow for exposure to a broad range of temperatures without significant adverse effect on product quality/performance. In this study, we evaluated the stability and performance of nasal glucagon at temperatures ranging from -20 to +30 °C (-4 to +86 °F) in order to mimic real world situations. Methods: Testing focused on characterization of drug product (glucagon amount) and combination product performance (consistent delivery to nasal cavity). Critical quality elements, including chemical purity and content, particle size, actuation force, delivered dose, shot weight, spray pattern and plume geometry, were evaluated after being exposed to temperatures from -20 and +30 °C, a range broader than a typically controlled room temperature product [i.e., Store at Controlled Room Temperature, 20° to 25°C (68° to 77°F); excursions permitted between 15° and 30°C (59° and 86°F)], such as glucagon for injection. Results: All testing demonstrated that 100% of critical quality elements were satisfied. Nasal glucagon could be exposed to frozen (-20 °C), refrigerated (2 to 8°C), and up to 30 °C conditions for the 2-year shelf life. The degradation of glucagon followed Arrhenius kinetics (i.e., slower degradation rates at lower temperatures). Temperature cycling studies showed no significant changes in the chemical/product performance attributes. Conclusions: These analyses indicate no adverse impact to nasal glucagon from the chemical and physical perspective when exposed to frozen, refrigerated, and up to 30 °C conditions. The stability across a broad range of temperatures facilitates the portability of nasal glucagon as a rescue medication for severe hypoglycemia. Disclosure B. W. Pack: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. J. Melnick: Employee; Self; Eli Lilly and Company, Employee; Spouse/Partner; Eli Lilly and Company. C. Breen: Employee; Self; Eli Lilly and Company. R. Allen: Employee; Self; Eli Lilly and Company. Funding Eli Lilly and Company

MGV354 was being developed as a novel ocular therapy for lowering of intraocular pressure, a key modifiable risk factor for glaucoma. MGV354 is an activator of soluble guanylate cyclase, an enzyme known to be involved in the regulation of IOP. MGV354 has been shown to robustly lower IOP over 24 h after a single topical ocular drop in rabbit and monkey pharmacology models. However, MGV354 failed to produce similar results in patients with ocular hypertension or open-angle glaucoma.With an objective of explaining the lack of efficacy in the clinic, we attempted to study whether human metabolism was significantly different from animal metabolism. The present study documents the investigation of metabolism of MGV354 in an effort to understand potential differences in biotransformation pathways of MGV354 in rabbits, monkeys, and humans.Overall twenty-six metabolites, formed via oxidative and conjugative pathways, were identified in vitro and in vivo. In vitro hepatic metabolism was qualitatively similar across species, with minor but distinct differences. There were no observable interspecies differences in the hepatic and ocular metabolism of MGV354. Although ocular metabolism was not as extensive as hepatic, the results do not explain the lack of efficacy of MGV354 in clinical studies. MGV354 was being developed as a novel ocular therapy for lowering of intraocular pressure, a key modifiable risk factor for glaucoma. MGV354 is an activator of soluble guanylate cyclase, an enzyme known to be involved in the regulation of IOP. MGV354 has been shown to robustly lower IOP over 24 h after a single topical ocular drop in rabbit and monkey pharmacology models. However, MGV354 failed to produce similar results in patients with ocular hypertension or open-angle glaucoma. With an objective of explaining the lack of efficacy in the clinic, we attempted to study whether human metabolism was significantly different from animal metabolism. The present study documents the investigation of metabolism of MGV354 in an effort to understand potential differences in biotransformation pathways of MGV354 in rabbits, monkeys, and humans. Overall twenty-six metabolites, formed via oxidative and conjugative pathways, were identified in vitro and in vivo. In vitro hepatic metabolism was qualitatively similar across species, with minor but distinct differences. There were no observable interspecies differences in the hepatic and ocular metabolism of MGV354. Although ocular metabolism was not as extensive as hepatic, the results do not explain the lack of efficacy of MGV354 in clinical studies.

Effective food packaging is a major factor in the current global drive to minimise food waste. Starch is an excellent oxygen barrier for packaging but it is brittle and moisture sensitive. The addition of layered minerals and plasticizers can significantly improve the moisture barrier and flexibility of the resulting composite. Some combinations of starch and plasticizer are incompatible but our results show that the addition of bentonite ensures the formation of coherent starch films with much improved moisture barrier regardless of the starch-plasticizer compatibility. It was clearly demonstrated that improvement of the moisture barrier was critically dependent on the layer charge of the bentonite used. Starch was readily accommodated in the interlayer space of bentonites with a layer charge of

INTRODUCTION Daily phlebotomy is often a standard procedure in hospitalized patients. Recently, this practice has begun receiving attention as a potential target for efforts focused on eliminating overuse. Several organizations have published their efforts in this arena. Interventions have included education, feedback, and changes to computerized provider order entry (CPOE) but have yielded mixed results. METHODS A quality improvement initiative to reduce the utilization of daily phlebotomy was conducted at a 505-bed Academic Medical Center. This project involved a combination of educational interventions and changes to CPOE. The primary end point evaluated was the daily performance of complete blood counts (CBCs) and basic metabolic profiles (BMPs) on medical and surgery units relative to the corresponding hospital census. RESULTS Over the course of this project from August 1, 2013, to September 23, 2016, there was a 15.2% reduction in CBCs (p < .001 for linear trend) and 13.1% reduction in BMPs. DISCUSSION Our results suggest that layering multimodal interventions that involve both "hard-wired" changes to CPOE and education and performance feedback can result in decreased utilization of phlebotomy.

The applicability of the n-nonane pre-adsorption method for characterising the porosity in clays is presented. Na-SD, a Na+-exchanged purified bentonite, and materials obtained by Al3+-exchange and acid treatments of Na-SD and SAz-1 were used. Nitrogen adsorption isotherms, at −196 °C, were determined before and after n-nonane pre-adsorption on each of the samples. In all materials, n-nonane remained adsorbed in ultramicropores after outgassing at 25 °C. Outgassing at higher temperatures (50, 75 and 200 °C) removed nonane and ultramicropores became available for nitrogen adsorption. All treatments on Na-SD led to increase in micropore volume. Larger ultramicropore and supermicropore volumes were obtained for Na-SD acid activated with HCl at 95 °C than for treatments at 25 °C with HCl or following Al3+-exchange (Al-SD), and increased with increasing acid concentration to 3 M. Activation with 4 M HCl led to the largest pore volume with contribution from mesopores. However, the specific external surface area was the same as that obtained for Na-SD, Al-SD and for most of the other acid activated samples. Treatments at 95 °C with 1 M and 6 M HCl promoted increase in specific external surface area. The micropore volumes and specific external surface area for SAz-1 treated with 1 M HCl at 95 °C were larger than those of Al-SAz-1, but lower than those obtained for corresponding materials derived from Na-SD. The n-nonane pre-adsorption method enabled micropore volumes and specific external surface areas to be obtained for all samples.

Quantitative bioanalysis of dried plasma spots (DPS) is not subject to the impact of hematocrit and sample non-homogeneity that are often encountered in dried blood spot (DBS) assay. In the present report, an evaluation of plasma microsampling for DPS has been conducted for the first time using ritonavir as a model compound orally administered to dogs. For this evaluation, an LC-MS/MS method was developed and validated according to the current health authorities' guidance and industry practice for the analysis of ritonavir in DPS samples. The measured ritonavir concentrations in the DPS samples prepared using SAFE-TEC devices and directly from the conventional wet plasma using standard pipette were compared with each other and against those of conventional wet plasma. Both DPS results correlated well with each other and were comparable to those of the wet plasma. Good incurred sample reanalysis results were obtained for the two sets of DPS samples and wet plasma as well. The current plasma microsampling for DPS can serve as an alternative to DPS sampling via standard pipetting and wet plasma in in vivo studies.

Regulatory agencies have recently issued drug-drug interaction guidelines, which require determination of plasma protein binding (PPB). To err on the conservative side, the agencies recommend that a 0.01 lower limit of fraction unbound (fu) be used for highly bound compounds (>99%), irrespective of the actual measured values. While this may avoid false negatives, the recommendation would likely result in a high rate of false positive predictions, resulting in unnecessary clinical studies and more stringent inclusion/exclusion criteria, which may add cost and time in delivery of new medicines to patients. In this perspective, we provide a review of current approaches to measure PPB, and important determinants in enabling the accuracy and precision in these measurements. The ability to measure fu is further illustrated by a cross-company data comparison of PPB for warfarin and itraconazole, demonstrating good concordance of the measured fu values. The data indicate that fu values of ≤0.01 may be determined accurately across laboratories when appropriate methods are used. These data, along with numerous other examples presented in the literature, support the use of experimentally measured fu values for drug-drug interaction predictions, rather than using the arbitrary cutoff value of 0.01 as recommended in current regulatory guidelines.

The effect of silver nitrate concentration, pre-washed bentonite (to remove extraneous salt) and back-exchange procedures have been explored to assess the type of silver species formed and their behaviour upon exposure to further salts. X-ray fluorescence was used to quantify the amount of silver present and whether in cation exchange sites, whereas X-ray diffraction and transmission electron microscopy identified the silver compounds present. A further objective was to assess the antimicrobial, barrier and dispersion properties of the silver/sodium bentonites when incorporated into a starch-plasticiser-clay coating used for packaging. The silver/sodium bentonites demonstrated very strong antimicrobial activity towards Escherichia coli, Kocuria rhizophila and Aspergillus niger. Incorporating just 0.03 wt% of silver/sodium bentonite in the coating (0.2 mmol/m2 Ag in dried coating with thickness of 14 mm) produced a > 4.4 log reduction against an initial loading of 2.1 × 105 CFU/object for E. coli. Water vapour barrier properties of coatings prepared on paper and containing the mixed silver/sodium bentonite were unaffected since water vapour transmission rate values of ~20-40 g/m2.day (23°C, 50% relative humidity) were maintained. Also the presence of silver did not adversely affect the clay dispersion. The Ag+ release profile from mixed silver/sodium clay upon addition of HNO3 and NaNO3 is discussed.

The concept and development of mixed modifier clays have been investigated in order to optimize clay dispersion within polymer matrices in general and polycaprolactone (PCL) in particular. A range of mixed modifier clays have been prepared by the inclusion of a second, more polar, organomodifier of much shorter chain length (Me3(CH2CH2OH)N+) within a benzyl(hydrogenatedtallowalkyl)dimethylammonium organoclay. The focus was to produce a range of organoclays with a systematic progression of selected polarities so that an optimum compatibility with the host polymer, PCL, could be achieved. The key to success was to attain that delicate balance where the long alkyl chains on the first modifier just overcame the layer–layer attraction whilst the second, shorter chain, modifier offered the potential to optimise the polarity of the clay surface and reduce the congestion in the interlayer space to ease polymer ingress. The organo-modification, subsequent polymer dissolution and casting were achieved using nitrobenzene as the solvent. X-ray diffraction (XRD) evidence, supported by, carbon/nitrogen analysis, proton nuclear magnetic resonance spectroscopy and thermogravimetry–mass spectroscopy, indicated that, when fully optimized, a homogeneous distribution of the two modifiers had been achieved within each individual interlayer space and that the amount of each modifier could be controlled. XRD data and transmission electron microscopy images confirmed that the extent of dispersion, of the mixed modifier clay in PCL, could be controlled to produce layered aluminosilicate–polymer systems that were either exfoliated, intercalated or a mixture of both.

Sacubitril/valsartan (LCZ696) has been approved for the treatment of heart failure. Sacubitril is an in vitro inhibitor of organic anion-transporting polypeptides (OATPs). In clinical studies, LCZ696 increased atorvastatin Cmax by 1.7-fold and area under the plasma concentration-time curve by 1.3-fold, but had little or no effect on simvastatin or simvastatin acid exposure. A physiologically based pharmacokinetics modeling approach was applied to explore the underlying mechanisms behind the statin-specific LCZ696 drug interaction observations. The model incorporated OATP-mediated clearance (CLint,T) for simvastatin and simvastatin acid to successfully describe the pharmacokinetic profiles of either analyte in the absence or presence of LCZ696. Moreover, the model successfully described the clinically observed drug effect with atorvastatin. The simulations clarified the critical parameters responsible for the observation of a low, yet clinically relevant, drug-drug interaction DDI between sacubitril and atorvastatin and the lack of effect with simvastatin acid. Atorvastatin is administered in its active form and rapidly achieves Cmax that coincide with the low Cmax of sacubitril. In contrast, simvastatin requires a hydrolysis step to the acid form and therefore is not present at the site of interactions at sacubitril concentrations that are inhibitory. Similar models were used to evaluate the drug-drug interaction risk for additional OATP-transported statins which predicted to maximally result in a 1.5-fold exposure increase.

MicroRNAs (miRNAs) are short noncoding RNAs, which post-transcriptionally regulate gene expression. miRNAs are transcribed as precursors and matured to active forms by a series of enzymes, including Dicer. miRNAs are important in governing cell differentiation, development, and disease. We have recently developed a feeder- and serum-free protocol for direct derivation of endothelial cells (ECs) from human embryonic stem cells (hESCs) and provided evidence of increases in angiogenesis-associated miRNAs (miR-126 and -210) during the process. However, the functional role of miRNAs in hESC differentiation to vascular EC remains to be fully interrogated. Here, we show that the reduction of miRNA maturation induced by Dicer knockdown suppressed hES-EC differentiation. A miRNA microarray was performed to quantify hES-EC miRNA profiles during defined stages of endothelial differentiation. miR-99b, -181a, and -181b were identified as increasing in a time- and differentiation-dependent manner to peak in mature hESC-ECs and adult ECs. Augmentation of miR-99b, -181a, and -181b levels by lentiviral-mediated transfer potentiated the mRNA and protein expression of EC-specific markers, Pecam1 and VE Cadherin, increased nitric oxide production, and improved hES-EC-induced therapeutic neovascularization in vivo. Conversely, knockdown did not impact endothelial differentiation. Our results suggest that miR-99b, -181a, and -181b comprise a component of an endothelial-miRNA signature and are capable of potentiating EC differentiation from pluripotent hESCs. Disclosure of potential conflicts of interest is found at the end of this article.

Selected instrumental techniques [dilatometry, thermogravimetry – mass spectrometry (TG-MS), and variable temperature – diffuse reflectance infrared Fourier transform spectroscopy (VT-DRIFTS)] have been used to investigate the role of moisture in the rehydroxylation reaction which causes expansion and mass gain in fired clay ceramics. The temperature range over which adsorbed water molecules and structural hydroxyl groups are desorbed from fired clay ceramic as it is reheated, and the nature of the structural hydroxyls that are formed as the ceramic is cooled and then held under controlled conditions have been explored. The mass chromatogram for m/z = 18, supported by VT-DRIFTS, showed that physisorbed water molecules were removed from the ceramic at about 105°C, whereas strongly bound molecules of water and structural hydroxyls were held to ≤500°C. Dilatometry revealed a marked contraction of the ceramic between 200°C and 330°C which corresponded to loss of strongly bound molecules of water. The VT-DRIFTS also showed that the interaction of water molecules with the ceramic body following reheating occurred in two stages and confirmed the kinetic law previously derived from mass gain and moisture expansion in fired clay ceramics.

The feasibility of applying Partial Least Squares (PLS) to the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) spectra of mineral mixtures, quarry sandstones and oilfield reservoir rocks has been investigated and shown considerable potential for accurate and precise mineralogical analysis. Rapid spectrum acquisition and data processing together with small sample size requirements are key advantages of the PLS–DRIFTS method. A PLS model was created from the DRIFTS spectra of mixtures of seven mineral standards chosen to represent the most frequently encountered minerals in sandstone-type rocks; quartz, dolomite, montmorillonite, illite, kaolinite, chlorite and albite. The PLS–DRIFTS model was able to quantify the mineral components of independent mixtures with an absolute error of 1 wt.% for all the minerals (concentration range 0–30 wt.%) with the exception of quartz which exhibited an absolute error of 3 wt.% (concentration range 50–90 wt.%). The results provided by applying this PLS–DRIFTS model to several sandstone-type quarry rocks and a suite of oilfield reservoir rocks were considerably better than anticipated even though the model did not describe all the mineral components present in the samples nor the entire variance of constituent mineral components (e.g. crystallinity). The model was not able to differentiate between montmorillonite and illite probably due to the similarity of the DRIFTS spectra of these minerals, but it was able to quantify the combined (montmorillonite + illite) concentrations to within 1 wt.%. The model over-predicted the concentration of albite in the quarry rocks due to the presence of K-feldspar, which has a similar DRIFTS spectrum and was not included in the model. However, the model accurately predicted the total (albite and K-feldspar) concentration to within 4 wt.%. A separate PLS–DRIFTS model constructed using the DRIFTS spectra of the oilfield reservoir rocks showed that the carbonate components, calcite and dolomite could be differentiated and quantified to within 5.0 and 3.6 wt.%, respectively. This feasibility study confirmed the strong potential of combining DRIFTS with a multivariate statistical approach such as PLS and it is clear that more sophisticated models, that incorporates and describes a higher percentage of the variance in unknowns, would further improve the predictions.

Variable temperature DRIFTS has been used to investigate temperature variation of the number and population of the different environments occupied by water on unmilled kaolin and samples ball milled for 3, 10 and 30 min. Increasing the milling time resulted in structural damage of the kaolin and an increase in the amount of hydrogen bonded water indicated by bands in the OH stretching and bending regions. Curve fitting of the spectra, collected at 50 °C intervals in the temperature range 25–500 °C, established that the intensity of the bands diminished as the temperature was increased but also revealed bands that were more stable to high temperatures or were generated as the sample temperature was increased. Bands at 3750, 3386 and 3200 cm −1 and 1680, 1650, 1634 and 1600–1580 cm −1 were identified in the OH-stretching and bending regions, respectively. In particular a band at 1670 cm −1 has been attributed to strongly hydrogen bonded water which acts to hold the deformed kaolin sheets together. Upon aging the samples the intensity of this band decreased and was replaced by a band at 1630 cm −1 . Boehmite was tentatively identified as a product of the milled kaolin.

The effects of carbonation of mechanochemically prepared C-S-H samples under ambient conditions for upto 6 months have been investigated by Raman spectroscopy and X-ray diffraction. The type and extent of carbonation are strongly dependent on the initial CaO/SiO2 (C/S) ratio of the samples. Amorphous calcium carbonate hydrate is formed within minutes upon exposure to air. It crystallizes, over time, to give primarily vaterite at C/S >= 0.67 and aragonite at C/S

In this study, we report the use of clay-based catalysts in the methoxylation of α-pinene, for the selective synthesis of α-terpinyl methyl ether, TME. The main reaction products and intermediates were identified by GC-MS. The reaction conditions (stirring rate and catalyst load) that afford a kinetic regime were established. SAz-1 (Cheto, Arizona, USA) source clay and a montmorillonite (SD) from Porto Santo, Madeira Archipelago, Portugal, were modified by ion-exchange with Al3+ to produce catalysts with markedly different acidities and textural properties. The catalysts based on the high layer-charge SAz-1 montmorillonite proved to be the most active. Ion-exchange with Al3+, followed by thermal activation at 150°C, afforded the highest number of Bronsted acid sites - a significant proportion of which were located in the clay gallery - and this coincided with the maximum catalytic activity. The influence of various reaction conditions, to maximize α-pinene conversion and selectivity, was studied over AlSAz-1. When the reaction was performed for 1 h at 60°C, the conversion reached 65% with 65% selectivity towards the mono-ether, TME. Similar conversions and selectivities required up to 50 h over zeolites and other solid acid catalysts. The kinetic dependencies of this reaction on temperature and reagent concentration, over the selected clays were also investigated. It was established that, in the temperature and reagent concentration regime studied, the reaction was first order with respect to α-pinene. The apparent activation energies over the two catalysts, calculated from Arrhenius plots, were almost identical at 72 kJ mol-1

A bentonite collected at Serra de Dentro (SD), Porto Santo Island, Portugal, and the source clay SAz-I (Cheto, Arizona) were ion-exchanged with different cations (Al3+, Ni2+, Cr3+ and Na+). Variable temperature diffuse reflectance infrared Fourier transform spectroscopy (VT-DRIFTS) of pyridine treated samples, thermal desorption of cyclohexylamine and real time mass spectrometry of the evolved gases were used to evaluate the acidic properties of the prepared catalysts. The catalytic activity of these ion-exchanged clays was tested in the acid-catalysed conversion of limonene at 150 degrees C, to yield isomerization products (terpinolene, alpha-terpinene, gamma-terpinene and isoterpinolene), disproportionation products (p-cymene and p-menthenes) and high molecular-weight compounds. The possibility of increasing the selectivity toward p-cymene, over a catalyst with substantial Lewis acid character, was particularly envisaged. Catalysts derived from SD were significantly more active than their SAz-I counterparts. This was mainly attributed to the greater inherent acidity, to the higher structural iron content (providing dehydrogenation activity) and to the higher nitrogen surface area of the starting SD clays. Within the Mn+-SD series, the order of activity decreased as Ni2+ > Al3+ > Cr3+ > Na+. A direct comparison between Al3+-SD (with maximized Bronsted acidity) and Ni2+-SD (with predominant Lewis acid character) provided no support for enhanced p-cymene production over Lewis acid sites. (C) 2005 Elsevier B.V. All rights reserved.

Raman spectroscopy has been used to follow the hydration of C3A and C4AF, two of the principal components of ordinary Portland cement (OPC), in the absence and presence of calcium sulphate (gypsum). Raman spectroscopy enabled in situ, real time analysis of the hydrating pastes. Analysis of the pastes by X-ray diffraction complemented the Raman data and confirmed sample composition. Subtle changes in the Raman spectra of the different pastes illuminated differences in hydration behaviour between C3A and C4AF. The similarities and differences between the various systems are discussed. The influence of carbon dioxide on the hydration products has also received attention.

Polymer-clay nanocomposites have been prepared by solution intercalation of poly(vinyl alcohol) (PVOH) into Na+ Montmorillonite (Na+ Cloisite(R)). XRD has been used to determine the dispersion of the individual clay platelets in the PVOH matrix. ATR-FTIR has been used to perform in situ diffusion experiments of water and acetone into nanocomposite films. The data has been compared to that obtained from the pure polymers to evaluate the barrier properties of the nanocomposites. The dominant process during water uptake was polymer solvation so the clay loading exerted little influence on the uptake rate. In contrast, the rate of diffusion of acetone was significantly reduced as the clay loading in the nanocomposite increased. (C) 2003 Elsevier B.V. All rights reserved.

The ageing of oil-well cement, Dyckerhoff class G, under saturated water vapour in the presence of carbon dioxide has been studied using the complementary techniques of Raman microscopy and environmental scanning electron microscopy. This combination of techniques has enabled the key components involved in the surface hydration processes to be identified in situ, their time evolution to be monitored directly (without the need for quenching and sample extraction) and this evolution of chemistry/mineralogy to be related to local structural changes. It has also enabled local chemical changes in this highly heterogeneous material to be related to the original cement grain mineralogy. High aspect ratio structural features, rich in aluminium and sulfur, were formed on the grain surface during the ageing process. These were identified as ettringite, which exhibited a diagnostic band at 988 cm−1 in the Raman spectrum.

One montmorillonite, STx-1 (Texas, USA), was activated with different amounts of Al and tetramethylammonium (TMA+) cations to obtain materials with a combined Al3+ and TMA+ content equal to its cation exchange capacity. The adsorption capacity of these samples was studied saturating them with hept-1-ene at room temperature. The samples were heated and the evolved gases analyzed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. Hept-1-ene reacted with the clays via proton transfer and resulted in the formation of a variety of reaction products (>60 hydrocarbons). In general, the presence of TMA+ cations significantly reduced the population of protons to selectively produce isomerization and hydration products.

Acid activated metakaolins (AAMKs) have been prepared by calcination of the natural clay at 600degreesC to provide a metakolin which was then leached at 80degreesC for 3 h using 1M, 2M, 3M, and 6M HCl. These materials were characterized and their ability to transform the off gases from HDPE decomposition into useful aromatic species was evaluated. The amount of adsorbed water and the number of acid sites increased with the severity of acid treatment, Variable temperature DRIFTS spectroscopy of pyridine treated samples revealed that both Brphinsted and Lewis acid centers were present until 425degreesC. Pyridine bonded to the Lewis acid centers was more thermally stable. The AAMKs were all selective to the production of toluene with respectable, but lesser, amounts of xylenes and trimethylbenzenes. This selectivity contrasts with that of acid leached and pillared smectites which are selective toward trimethylbenzene. (C) 2002 Elsevier Science (USA).

Phenylphosphonic acid undergoes a topotactic reation with the available hydroxyls on the gibbsite sheet of kaolin and halloysite during reflux in a water–acteone mixture at 70°C. The reaction occurs much more rapidly with halloysite than with kaolin and the number of hydroxyls consumed is much higher for the halloysite than the kaolin. Variable temperature X-ray diffraction confirmed that the d-spacing for both kaolin–phenylphosphonic acid (KPPA) and halloysite–phenylphosphonic acid (HPPA) remained stable at 15.4 A to temperatures greater than 450°C. Variable temperature diffuse reflectance infrared Fourier transform spectroscopy (VT-DRIFTS) together with TG–MS analysis of the evolved gases confirmed that the phenyl ring was not thermally desorbed until after dehydroxylation began to take place. Moreover, these techniques showed that the complexes contained water which was desorbed near 150°C. In addition VT-DRIFTS showed that this water was hydrogen bonded to the remaining surface hydroxyls on the gibbsite sheet resulting in a shift of the AlAlOH band from 934 to 885 cm−1 in both HPPA and KPPA. This band shifted back to 934 cm−1 when the hydrogen bonded water (characterised by an OH bending mode at 1643 cm−1 and an OH stretching mode at 3547 cm−1) was thermally desorbed.

Graph Presented) The competitive adsorption of poly(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVOH) onto Na-bentonite has been assessed quantitatively. Particular emphasis was focused on the amount of organic located within the bentonite interlayer and any subsequent eff ects on the extent of layer expansion. The individual isotherms showed strong adsorption for both PVOH and PEG at amounts lower than the quantities required to produce a fully loaded bilayer (0.33 g of PVOH/g of clay) and single layered structures (0.10 g of PEG/g of clay), respectively. Above these concentrations, the incremental amounts adsorbed were smaller, and the concentration of adsorbates in solution gradually increased. Na-bentonite adsorbed more PVOH than PEG at any given concentration. In the competitive study, the amount of PVOH adsorbed was enhanced in the presence of PEG (0.10 and 0.30 g/g of clay), but less PEG was adsorbed. At low loadings of PVOH (0.02-0.10 g/g of clay), the amount of adsorbed PEG was increased but at higher PVOH levels PEG adsorption was reduced. The XRD data showed stepped changes in the d-spacing as the adsorbed amounts of both PEG and PVOH increased. The PEG-bentonite samples did not expand beyond a bilayer structure (18 A˚), but the XRD data for PVOH-treated samples indicated the formation of multilayer structures (d ≥ 44 A˚).

Shape Memory Polymers (SMPs) exhibit the intriguing ability to change back from an intermediate, deformed shape back to their original, permanent shape. In this contribution a systematic series of t-butylacrylate-co-poly(ethyleneglycol) dimethacrylate (tBA-co-PEGDMA) polymers have been synthesised and characterised prior to incorporation of organoclay. Increasing the poly(ethyleneglycol) dimethacrylate (PEGDMA) content in increments of 10% increased the storage modulus from 2005 to 2250MPa, reduced the glass transition temperature from +41 to −26°C and reduced the intensity of the associated tan δ peak. The tBA-co-PEGDMA crosslinked networks displayed useful shape memory properties up to PEGDMA contents of 40%. Above this PEGDMA percentage the materials were prone to fracture and too brittle for a realistic assessment of their shape memory capability. The system containing 90% t-butylacrylate (tBA) and 10% PEGDMA was selected as the host matrix to investigate how the incorporation of 1 to 5mass% of a benzyl tallow dimethylammonium-exchanged bentonite (BTDB) influenced the shape memory properties. X-ray diffraction data confirmed that BTDB formed a microcomposite in the selected matrix and exerted no influence on the storage modulus, rubbery modulus, glass transition temperature, Tg, or the shape or intensity of the tan δ peak of the host matrix. Therefore, it was anticipated that the presence of BTDB would have no effect, positive or negative, nor on the shape memory properties of the host matrix. However, it was found that the incorporation of clay, especially at the 1mass% level, significantly accelerated the speed, compared with the clay-free SMP, at which the microcomposite returned to the original, permanent shape. This accelerated return to the permanent shape was also observed when the microcomposite was coated onto a 100μm PET film.

Paper and paperboard are the most widely used packaging materials for both food and non-food products. Because they are composed of highly porous cellulose networks, they readily absorb moisture in high humidity environments or when in contact with liquid or high moisture foods. Therefore they are often coated with hydrophobic coating materials such as polyethylene (PE) to improve their water-resistant properties. One of the major uses of such hydrophobic material coated paperboard is a disposable single-use paper cup with or without a lid. Today, the paper-based materials are coated with a thin layer of a petroleum derived plastic, mostly polyethylene, which has provided the cups and other packaging solutions with the required barrier property and water resistance. Hence, the ongoing challenge is to coat the paper with a biobased, hydrophobic polymeric material which must be repulpable or otherwise biodegradable in most of the environments considered. Many interesting developments are already known for the manufacturing of cellulose-based products, such as microfibrillated celluloses (MFC's) or modified celluloses, usable in the paper packaging industry. Paper and paperboard in combination with Green-Polyethylene, MFC's and polyhydroxyalkanoates (PHA's) seems to be the most promising solution for the packaging industry in the near future and the development of the thermoplastic modified celluloses for the next future. Regarding environmental considerations, PHA is a promising solution for the paper packaging industry but the problem of material recycling has to be solved and a solution comparable with the recyclability of PE-coated paper packaging products should be obtained. This review consists of a critical analysis of published results of 1-way food packaging and discusses more in detail what will be necessary for the development of 1-way food packaging based solely on wood derived products and biodegradable polymers.

SWy-2 (Wyoming), Sap-Ca saponite (California) and SAz-1 (Cheto, Arizona) were exchanged with different cations (Al, Ni, Mg, Ca and Na). The catalytic activity of these ionexchanged clays was measured directly using the isomerization of α-pinene at 80°C for 2 h to yield camphene, limonene and other minor products. The order of activity for the different cationexchanged forms was Al > Ni > Mg > Ca > Na, which correlated well with the known polarizing power of these cations and the resulting interlayer acidity. Catalysts derived from Sap-Ca were the most active followed by SWy-2, with SAz-1 the least active by a considerable margin. The greater activity of Sap-Ca over SWy-2 was attributed to the high tetrahedral charge in the former. Reduction of the layer charge of SAz-1 using Li fixation caused a significant improvement in the catalytic activity of the Al-exchanged reduced-charge SAz-1.

Derivative thermograms (DTG) for the desorption of dimethylformamide (DMF) from Mn+−SWy−2/DMF complexes can be used to distinguish between different exchange cations simply by the temperature at which the most strongly held DMF molecules are desorbed. The maxima for the desorption of this strongly bound DMF in the DTG traces for Mg2+−, Ca2+− and Na+−SWy were at 420, 330, and 220 °C, respectively. Variable-temperature X-ray diffraction confirms that the DMF is present as a single layer of molecules in the clay gallery at these temperatures. Variable-temperature diffuse reflectance Fourier transform spectroscopy (VT-DRIFTS) has shown that the strongly held DMF molecules are directly coordinated to the exchangeable cations via the carbonyl group. The method is simple and robust, requires no specialized preparation methods and the diagnostic capability is not adversely influenced by the presence of moisture. VT-DRIFTS has shown that coadsorbed water is desorbed at temperatures below 100 °C

High-density polyethylene, HDPE, has been thermally decomposed in a thermobalance and the evolved gases passed through a bed of catalyst. The resulting transformation products were trapped and subsequently identified using GC-MS. Two smectites of different octahedral compositions were acid-activated under conditions known to produce catalysts of differing activity. Three different treatments were used for each smectite, thus providing six samples for evaluation. The thermal and catalytic decomposition of HDPE was studied under isothermal (60 min at 420°C) and dynamic (35–650°C at 10°C min−1) conditions. The thermal decomposition of HDPE yielded characteristic quartets of peaks in the chromatogram which were assigned to n-alkanes, 1-alkenes, x-alkenes and α,ω-dienes in the range C4–C22. Species of higher molecular weight than C22 were not detected. All six catalysts converted the alkenes present in the thermally generated off gases into light gases and aromatic species. Mono-, di- and trimethylbenzenes were the most abundant aromatic species although small quantities of ethylbenzenes and naphthalenes were produced. More aromatics were produced at 420°C than at temperatures up to 650°C, whereas the reverse was true for branched alkanes. The total conversion of HDPE increased with both the extent of acid treatment and the process temperature, whereas the proportion of aromatics produced was greatest for catalysts prepared using short acid-treatment times.

The progressive adsorption of N-methylformamide (NMF) onto Ca-, Mg-, and Na-exchanged Wyoming bentonite (Mn+ - SWy-2) together with its subsequent thermal desorption has been studied using a variety of complementary techniques. The derivative thermograms (DTG) for the desorption of NMF from Mn+-SWy-2 exhibit three maxima at temperatures which depend on the exchange cation. In Mg-SWy-2 these maxima occur at 130, 200, and 400 degrees C, whereas in Na-SWy-2 they occur at 100, 150, and 190 degrees C. Each of these maxima has been assigned to different sites and/or environments for sorbed NMF using variable temperature-X-ray diffraction (VT-XRD) and variable temperature-diffuse reflectance infrared Fourier transform spectroscopy (VT-DRIFTS). Each fully loaded Mn+-SWy-2/NMF complex has two layers of NMF in the gallery, which decreases to a single layer prior to the complete removal of NMF from the complex. The temperatures at which major weight losses occur coincide with decreases in the interlayer spacing. VT-DRIFTS has shown that at low temperatures NMF was removed from NMF clusters, similar to those in liquid NMF, while at high temperatures the NMF molecules are firmly bound and directly coordinated to the exchangeable cations. Unusual shifts in the C-H and N-H absorption bands were observed, indicating a unique orientation of these groups, which probably reflects their keying into the hexagonal cavities of the tetrahedral sheet of the aluminosilicate layer.

Three montmorillonites SWy-2 (Wyoming, USA), STx-1 (Texas, USA) and SAz-1 (Cheto, Arizona, USA) and a saponite Sap-Ca (California, USA) were activated with different amounts of Al3+ and tetramethylammonium (TMA(+)) cations to obtain materials with a combined Al3+ and TMA(+) content equal to their CECs. The catalytic activity was evaluated by reacting alpha-pinene at 120 degrees C for 1 h to yield camphene, limonene, and other minor products and compared to clays prepared without TMA(+). The total conversion over Sap-Ca, STx-1, SWy-2, and SAz-1 was 90%, 80%, 65%, and 25%, respectively, in samples treated with Al3+ alone. Similar yields were obtained over Al3+/TMA(+)-exchanged forms when the TMA(+) content was less than 20% CEC, but in general the presence of TMA(+) significantly reduced the total conversion. The activity of the Al3+-exchanged clays for this test reaction is attributed to their ability to remain expanded at the temperature of the activation process thus permitting easy access of the reagent. The comparatively low conversion over catalysts derived from SAz-1 was attributed to its high layer charge which restricted access to the active centers in the clay gallery.

Ni2+- and Al3+-exchanged montmorillonite are known to demonstrate Lewis and Bronsted acidity, respectively, when probed using the diagnostic base pyridine (C. Breen, Clay Miner., 1991, 26, 487). Thermogravimetric analysis (TGA) of pyridine saturated Al3+- and Ni2+-montmorillonite differ whereas here it was found that cyclohexylamine (CHA) desorption profiles were very similar, albeit CHA was held to a higher temperature on Ni2+-SWy-2 than on Al3+-SWy-2. Evolved gas analysis (EGA) of the desorbed products revealed significant differences in the amount of cyclohexylamine, cyclohexene, methylcyclopentene, benzene and aniline produced, which demonstrated different decomposition pathways for CHA sorbed to Al3+- and Ni2+-exchanged SWy-2. For example, cyclohexene is produced over both exchange forms whereas aniline and methylcyclopentene were the major products over Ni2+- and Al3+-SWy-2, respectively. Variable-temperature DRIFTS was unable to distinguish between CHA-treated Al3+- and Ni2+-SWy-2 at temperatures

The interaction of polymers with clays is considered with particular emphasis on the adsorption of polycations of the type [CH2CHOHCH2N(CH3)(2)](n)(n+) onto a low iron Texas bentonite, Westone-L (WL). The influence of clay type, particle size and resident cation on the amount of adsorbed polycation is reported along with variable temperature X-ray diffraction of the resulting complexes. The information obtained from Cs+- and Na+-WL suspensions using Cs-133 and Na-23 solution phase NMR is summarised and used to show that this technique can provide quantitative information regarding the displacement of Cs+-ions from the exchange sites by polycation in suspension and reflect subtle in situ changes intimated from Zeta potential measurements. The use of polycation-exchanged clays as scavengers of p-nitrophenol from water is described as is the significant activity of acid-treated polycation-exchanged clays for the catalytic isomersion of alpha-pinene to camphene and limonene. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

SWy-2 (Wyoming), STx-1 (Texas), and SAz-1 (Cheto, Arizona) montmorillonite and Sap-Ca saponite (California) were treated with different amounts of 12 M HCl and 1 M tetramethylammonium (TMA(+)) chloride solution at room temperature. The catalytic activity of these hybrid acid-activated organoclays (AAOCs) was directly measured using the isomerization of alpha-pinene at 120 degrees C for 1 h to yield camphene, limonene, and other minor products and compared to clays acid-treated in the absence of TMA(+) cations. The total conversion for the isomerization of cc-pinene was excellent for AAOCs formed from SWy-2 (88%) and STx-1 (73%), moderate for Sap-Ca (50%), and low for SAz-1 (20%). Samples treated with TMA(+) alone did not exhibit any marked catalytic activity. Acid-treated Sap-Ca and STx-1, which contained no TMA(+) cations were also effective catalysts for the isomerization process. TMA(+) cations were unexpectedly resistant to exchange by protons.

This contribution reports the coupling of TG with FTIR, MS and GC-MS (Synergic chemical analysis). During thermogravimetric analysis the gases evolved are analysed using 'real-time' FTIR and MS. Simultaneously the gases are collected on an absorbent trap (organic trap module, OTM) for subsequent analysis using GC-MS. As an example the technique has been used to identify the products evolved from a printed circuit board during thermal oxidation. The use of TG-FTIR-MS-OTM-GC-MS provided information that could not be available through single techniques alone. For example, it was possible to ascertain the temperature range over which bromophenol was released. (C) 1999 Elsevier Science B.V. All rights reserved.

The adsorption isotherms for the octylphenol ethoxylate, TX100, onto a range of bentonites and a saponite have been determined and the resulting thermal stability of composites has been studied. In general TX100 exhibited a high affinity for the different clay surfaces although the maximum amount adsorbed varied with both clay type, layer charge density and resident exchange cation. XRD and variable temperature XRD showed that TX100 was adsorbed into the interlamellar region, and that the thermal stability of the clay/TX100 composite was dependent upon the exchangeable cation present. For monovalent cation exchanged clays (M+-clay/TX100) the TX100 decomposed between 220 and 300 °C, and the d001 spacing decreased from 15.2 to 9.6 A. In contrast, divalent cation exchanged clays imparted a greater thermal stability to the complex (M2+-clay/TX100) owing to coordination of adsorbed TX100 to the exchange cation, wherein weakly coordinated TX100 was stable to 270 °C and strongly coordinated TX100 was held to temperatures in excess of 300 °C. FTIR analysis of the gases evolved evolved during thermogravimetry confirmed that the octylphenol unit was desorbed from M2+-clay at temperatures below 400 °C and that portions of the ethoxylate chain were held to 500 °C.

HDPE was thermally decomposed in a thermobalance and the evolved gases were passed through a bed of catalyst. Two acid activated clays of different structure were used, i.e. sepiolite (SEP), which is a fibrous clay mineral, and smectite (K10) which is a layered mineral. In addition two pillared smectites were studied one which was pillared with an Al species (AZA) and the other with an Al/Fe-species (FAZA). The thermal and catalytic decomposition of HDPE was studied under dynamic (35 to 650°C at 10°C min –1 ) and isothermal (60 min at 420°C) conditions. The evolved gases were analysed using TG-OTM-GC-MS. The thermal decomposition of HDPE yielded characteristic quartets of peaks assigned to n-alkanes, alk-1-enes, alk-x-enes and α,ω-dienes in the range C 4 -C 20 . Species of higher molecular weight than C 20 were not detected. All four catalysts converted the alkenes present in the thermally generated off gases into light gases and aromatic species including respectable quantities of toluene, xylenes, tri- and tetra-methylbenzenes. Ethylbenzenes and naphthalenes were produced to a lesser extent. AZA and FAZA produced the largest yield of aromatics and sepiolite is considered to produce significant quantities of low molecular weight gases in the isothermal process. The product distribution over sepiolite suggested that there were fewer dehydrocyclisation sites on this catalyst. None of the catalysts used was capable of cracking the saturated alkanes.

The uptake curves for the adsorption of a polycation ([CH2CH(OH)CH2N(CH3)(2)](n)(n+)(Cl)(n)(n-)) onto a low iron Texas bentonite, WL, have been determined and compared with those onto two source smectites, Swy-1 and SAz-1. The polycation exhibited a marked affinity for all the smectite surfaces but polycation uptake was maximized on the fine fractions of Na+-WL. Variable temperature X-ray diffraction of the clay polycation complexes showed that the polycation was segregated into different interlayers at loadings below 30% of the CEC. The adsorption of benzene onto TMA(+)-exchanged SWy-1, SAz-1, and WL showed that, despite having a comparable layer charge to SWy-1, WL was as poor a sorbent for benzene as SAz-1, which has a much higher layer charge. The adsorption of p-nitrophenol (PNP) from aqueous solution onto the TMA(+)-exchanged sorbents exhibited the same trends, although a smaller amount was adsorbed due to the greater size of PNP. The amount of PNP adsorbed by polycation-treated SWy-1 depended upon the polycation loading, and PNP uptake maximized at loadings of 28 and 46 mg (g clay)(-1). At higher loadings (80, 102, and 147 mg (g clay)(-1)) the uptake curves became linear and the PNP uptake decreased with increased polycation loading. No polycation-treated clay was as effective as TMA(+)-exchanged SWy-1 for the removal of PNP from water. (C) 1998 Academic Press.

Samples of SWy-2 and SAz-1 loaded with increasing amounts of the polycation magnafloc 206, [(Me2NCH2CHOHCH2)(n)]Cl-n+(n), were acid-treated using 6 M HCI at 95 degrees C for 30, 90 and 180 min. The activity of these acid-activated polycation-exchanged clays for the conversion of alpha-pinene to camphene and limonene was determined and compared with that from clay samples (without polycation) acid-treated in the same manner. Acid treatment of polycation-exchanged bentonites produced hybrid catalysts which enhanced the activity of the clays for the isomerisation of alpha-pinene to camphene and limonene. The presence of the polycation had a more marked influence on the activity of samples derived from SAz-1 increasing the yield from 25% for acid-activated SAz-1 with no added polycation to 50% camphene for acid-activated polycation-exchanged SAz-1. The increase in yield for corresponding samples derived from SWy-2 was only from 42 to 52%. This enhancement in yield for samples derived from SAz-1 was attributed to the increased hydrophobicity of the polycation loaded clay whilst the comparable yields for SWy-2 in the absence and presence of polycation may suggest that SWy-2 disperses well in the non-polar a-pinene. The total yields (based on alpha-pinene) for the most active catalysts was between 80 and 90%. These yields are directly comparable with those obtained by others using zeolites and pillared clays although the acid-activated polycation-treated clays were marginally less selective towards camphene. (C) 1998 Elsevier Science B.V.

The isotherms for the adsorption of a polyalkylene glycol (PAG1), of molecular weight

23Na solution phase NMR has been evaluated as an in situ probe to study the adsorption of tetramethylammonium (TMA+) and two polycations, FL17 ([(Me2NCH2CHOHCH2)n]n+Cln) and Magnafloc 1697, ([(CH2CHCH2N(Me)2CH2Cmacr;HCH2)n]n+Cln), onto clays in aqueous suspensions containing 2.5 mass% low iron Texas bentonite. The NMR data shows the effectiveness of the organocations at displacing Na+ from the bentonite surface. This information has been correlated with that obtained from particle-size and electrophoretic measurements in aqueous solution, together with information from adsorption isotherms. These results have been compared to those obtained in parallel studies using 133Cs solution phase NMR. FL17 and 1697 both exhibited high affinity adsorption isotherms on Na+- and Cs+-clay, whereas the adsorption of TMA+, which represents the cationic portion of the polymers was of lower affinity. Na+-bentonite adsorbed almost twice the amount of polycation required to fulfill the cation-exchange capacity (CEC) of the bentonite. The electrophoretic and particle size data indicated significant differences in the size of the polycation/clay flocs and the amount of polymer adsorbed on the external faces of the flocs in the presence of Na+- and Cs+-exchange ions. Correlation of this data with the NMR results suggests that the Na+-bentonite/polycation flocs are large, of low density, and that the polycation is concentrated in the interior while the Na+-ions occupy exchange sites on the external faces. Copyright 1997 Academic Press. Copyright 1997Academic Press

Five layered silicates in which the octahedral sheet contained differing amounts of Al, Mg, Fe, and Li were acid leached using acid concentrations and treatment temperatures selected to produce materials in which the octahedral sheet was depopulated in a controlled, stepwise (yet comparable) manner. SAz-1 and JP are dioctahedral smectites with octahedral compositions rich in Mg and Al, respectively. SWa-1 is a ferruginous smectite and ST an iron-rich beidellite. The fifth mineral was a trioctahedral hectorite which contains almost exclusively octahedral Mg. The Bronsted acidity and catalytic activity of the resulting materials were highest for the samples prepared with the mildest acid treatments but decreased as the octahedral sheet became increasingly depleted. Only the hectorite exhibited no catalytic activity despite the proven existence of Bronsted acid sites. The elemental composition of the starting material did not appear to make a significant contribution to the catalytic activity for the chosen ...

Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray diffraction (XRD) have been employed to investigate the adsorption of water soluble polymers from aqueous solution onto a clay mineral surface in situ, to gain an understanding of the interactions occurring at the microscopic level in water based muds (WBM). The water soluble polymers studied were; polyethylene glycol (PEG) (molecular weight, M w , 300 and 1000) (neutral), polyamine (FL15) ( M w 5000) (cationic) and polyacrylic acid, PAA, ( M w 2000) (charge dependant on pH) to establish the effect of polymer charge on the nature and extent of adsorption. XRD and ATR-FTIR spectroscopy have shown that water soluble polymers adsorb onto clay dispersions and are stable when deposited as thin solid films. XRD indicates that PEG stacks as either one or two layers whereas PAA and FL15 are restricted to a single layer between the clay lamellae. ATR-FTIR spectroscopy showed that FL15 penetrated the Na–SWy-1 films which contained low loadings of PEG without displacing any of the resident PEG. When a bilayer of PEG was present, FL15 did not penetrate into the film. Both PAA and PEG adsorbed onto FL15 loaded Na–SWy-1 films irrespective of FL15 loading or the molecular weight of the PEG. ATR-FTIR indicated that significant adsorption occurred in under 30 s and the adsorption rate was not influenced by the presence of a second polymer preloaded into the clay.

XRD, FTIR spectroscopy, cyclohexylamine desorption, potentiometric titrations and catalytic activity in an ether-forming test reaction have been used to investigate mildly acid-treated montmorillonite (SAz-1) and hectorite. The number of acid sites obtained from the cyclohexylamine desorption agreed with the accepted cation exchange capacity values for all samples. No evidence of any free protons was found in the potentiometric titration curves, which proved that complete autotransformation of the acid-treated samples had occurred over a much shorter period than previously recorded. Acid sites associated with Al3+ (Fe3+) released from the SAz-1 structure during acid treatment and subsequent autotransformation were of sufficient strength to catalyse the test reaction and produce tetrahydropyranyl ether in 80% yield. The complete absence of catalytic activity in the acid-treated hectorite samples confirmed that acid sites associated with interlayer Mg2+ and Li+ were unable to catalyse the test reaction.

In this study, we report the use of clay-based catalysts in the methoxylation of limonene, for the selective synthesis of α-terpinyl methyl ether. Na-SAz-1, Ca-SWy-2 and Sap-Ca source clays and a montmorillonite (SD) from Porto Santo, Madeira Archipelago, Portugal were modified by (i) ion-exchange with Al, Fe, Ni and Na and (ii) acid activation, to produce catalysts with markedly different acidic and textural properties. The lack of activity of Ni 2+ -SAz-1 (with Lewis acidity maximized), provided evidence that the process occurs preferentially on Bronsted acid sites. The catalysts based on the high layer-charge SAz-1 montmorillonite proved to be the most active. Ion-exchange with Al 3+ , followed by thermal activation at 150 °C, afforded the highest number of Bronsted acid sites located in the clay gallery and this coincided with the maximum catalytic activity. The influence of various reaction conditions, to maximize limonene conversion and selectivity, was studied over Al-SAz-1. When the reaction was performed for 20 h at 40° C, the conversion reached 71% with 91% selectivity to the mono-ether. Mild acid activation (1 M HCl, 30 min, reflux) of the raw SAz-1 clay leads to a material with a good catalytic behaviour (slightly inferior to Al-SAz-1), while any increase in the severity of the acid-treatment (6 M HCl, 30 min, reflux), caused a marked decrease in catalytic activity.