Solvent Purity Research Articles

Digital twinning, prediction and multi-objective optimization of an azeotrope system separation process in pharmaceutical manufacturing process

Digital twin is to make full use of the physical model, sensor update, operation history and other data to integrate multidisciplinary, multi-physical quantity, multi-scale and multi-probability simulation process, and to complete the full life cycle process of the corresponding physical equipment in the virtual space. In this paper, digital twin technology was used to simulate the production process of a pharmaceutical workshop, thus realizing solvent recovery by an azeotrope system separation process. The separation was optimized by multi-objective genetic algorithm. separation process, wherein the polynomial curve fitting and entropy-weighted TOPSIS data evaluation algorithms were combined to optimize the operating parameters, then the solvent purity and yield reach 99.96 % and 77.9 %, respectively, which is much higher than the corporate requirements. In addition, the effectiveness of the digital twin in providing data-driven prediction capability was verified by a CNN-LSTM-based regression prediction model, and the CNN-LSTM model has an accuracy of more than 98.9 % for all prediction results. Finally, a 3D visualization model was built using the Unity engine, enabling researchers to visualize and explore changes in key metrics during the separation process. This study can provide some guidance for digital transformation and intelligent development in pharmaceutical industry.

Exploring the Impact of Cationic Surfactant Ctab on Bleu Brilliant G 250 De Cosmassie: Implications for Health Management and Environmental Sustainability

Background: Surfactants are ubiquitous in both natural and industrial processes due to their unique ability to reduce surface tension and facilitate interactions between hydrophilic and hydrophobic substances. Cationic surfactants like cetyltrimethylammonium bromide (CTAB) are of particular interest because of their widespread applications in areas such as healthcare and environmental management. The interaction between surfactants and dyes, such as Bleu Brilliant G 250 de Cosmassie, is critical in industrial processes, especially in the textile industry where wastewater treatment poses significant environmental challenges. Objective: The aim of this study was to explore the thermodynamic behavior of CTAB when combined with Bleu Brilliant G 250 de Cosmassie in aqueous solutions at room temperature. It sought to determine the critical micelle concentration (CMC) and the degree of counter-ion dissociation (α), and to calculate the changes in Gibbs free energy (ΔGm), enthalpy (ΔHm), and entropy (ΔSm) of the system. Methods: The study employed conductometric and spectrophotometric techniques to analyze the CTAB-dye interactions. Solutions were prepared with varying concentrations of CTAB and Bleu Brilliant G 250 de Cosmassie in deionized water, ensuring solvent purity through stringent conductivity and pH monitoring. Electrical conductance was measured at different temperatures to determine the CMC, while absorbance spectra were recorded to observe changes in the interaction between the surfactant and dye. The degree of counter-ion dissociation was calculated by the slope ratio method, and thermodynamic parameters were computed using established equations. Results: The conductometric studies revealed an increase in CMC with temperature, indicating a stabilization of surfactant monomers at higher temperatures. For CTAB and Bleu Brilliant system 1, the CMC was found to be 0.8 with α valued at 0.83. For system 2, the CMC values were 1.55 and 1.6 with α values of 1.01 and 0.91, respectively. Thermodynamically, the system displayed a Gibbs free energy of micellization of -33.09 KJ/mol, an enthalpy change of -6.53, and an entropy change of 0.1325 JK^-1 mol^-1. Conclusion: The study concluded that the interaction between CTAB and Bleu Brilliant G 250 de Cosmassie is influenced significantly by temperature, which affects the micellization behavior and thermodynamic properties. The findings contribute to a better understanding of the fundamental thermodynamic parameters influencing surfactant-dye interactions, providing insights that may improve industrial processes and environmental sustainability.

Multivariate HPLC system assessment and optimization for traditional Chinese medicine: a case study of Gastrodia elata.

The development of HPLC analytical methods for traditional Chinese medicine is intricate and time-consuming, influenced by factors such as column wear, solvent purity, and instrumental settings. A comprehensive evaluation of the HPLC system is crucial to mitigate potential variability and ensure the reliability of data. This is especially important given the complex and synergistic nature of the chemical components in traditional Chinese medicine, necessitating a multivariate measurement system analysis (MSA) to assess multiple correlated quality characteristics effectively. This study introduced a multivariate MSA method based on weighted principal components (WPC) to evaluate the HPLC system for the determination of metabolites in Gastrodia elata. By integrating multiple principal components and assigning weights according to their eigenvalues, the WPC method significantly enhanced both accuracy and robustness. It demonstrated a repeatability and reproducibility (% R&R) of 26.43% and a number of distinct categories (ndc) index of 5, confirming the system's acceptability. A full factorial experimental design was employed to identify key performance factors, leading to the recommendation to use five reference solutions for the standard curve and to triple sample preparations for improved precision and accuracy. Monte Carlo simulations confirmed the reliability of the system, showing % R&R and ndc values that follow a normal distribution, ranging from 19% to 22% and 6.07 to 7.38, respectively. Chromatographic conditions were optimized using a Box-Behnken experimental design. Subsequent validation experiments verified the method's high accuracy and reliability, with all relative standard deviation values for analytical precision, repeatability, and stability below 5%. The method also exhibited high recovery rates, exceeding 91% across three concentration levels, with RSD values under 4%. In conclusion, the application of a WPC-based multivariate MSA enabled a detailed evaluation of the HPLC system, ensuring accurate and reliable measurement of quality attributes. This method exemplified a scientifically rigorous approach for developing analytical methods in traditional Chinese medicine, enhancing both precision and reliability.

The development of life cycle greenhouse gas emission footprints of novel pathways for the solvent-assisted and solvent-electromagnetic heating oil sands extraction processes

Steam-based oil sands extraction methods are emissions-intensive. Solvent-assisted and solvent-electromagnetic heating are alternative methods with the potential to lower greenhouse gas emissions (GHG). However, identifying an energy-efficient process pathway for these technologies remains a major concern. This is a gap in the research. In this study, we developed simulation models to assess the performance of solvent-assisted, solvent-electromagnetic heating, and steam-assisted oil sands extraction central processing facilities. Three central processing facilities (pathways) were developed for solvent-assisted and solvent-electromagnetic heating processes to recover bitumen and solvent from emulsions. Pathways I and III use a low-temperature and a high-temperature distillation system, respectively, to purify the solvent. Pathway II uses a high-pressure separator to lower the amount of non-condensable gases in the solvent. Each pathway was applied to a deep and a shallow reservoir. Sensitivity and uncertainty analyses were conducted to present the GHG emission results. The results show that pathways I and III produce satisfactory solvent purity and minimize solvent losses in the central processing facility, and pathway II does not. Pathway II can be applied when a high degree of purity is not required. The life cycle GHG emissions from pathways I and II may not be favorable to the solvent-assisted process if the electricity emission factor and solvent-to-oil ratio are high. The lowest GHG emissions are from pathway III. The life cycle GHG emissions of the solvent-electromagnetic heating extraction in pathway III range from 34.4 to 61.7 and 23.3 to 43.9 kgCO2e/b-e for the deep and shallow reservoirs, respectively, while solvent-assisted emissions range from 26.6 to 48.2 and 20.2 to 40.0 kgCO2e/b-e for the deep and shallow reservoirs, respectively. Steam-assisted gravity drainage emissions range from 72.7 to 111.6 kgCO2e/b. The results show that solvent-assisted and solvent-electromagnetic heating processes can provide better performance than steam-assisted gravity drainage when a high-temperature distillation is installed in the central processing facility to recycle the solvent.

In situ Synthesis of Supramolecular Polymers: Finding the Right Conditions when Combining Covalent and Non-Covalent Synthesis.

The combination of covalent and non‐covalent synthesis is omnipresent in nature and potentially enables access to new materials. Yet, the fundamental principles that govern such a synthesis are barely understood. Here, we demonstrate how even simple reaction mixtures behave surprisingly complex when covalent reactions are coupled to self‐assembly processes. Specifically, we study the reaction behavior of a system in which the in situ formation of discotic benzene‐1,3,5‐tricarboxamide (BTA) monomers is linked to an intertwined non‐covalent reaction network including self‐assembly into helical BTA polymers. This system shows an unexpected phase‐separation behavior in which an interplay of reactant/product concentrations, side‐products and solvent purity determines the system composition. We envision that these insights can bring us one step closer to how to design the synthesis of systems in a combined covalent/non‐covalent fashion.

In situ Synthesis of Supramolecular Polymers: Finding the Right Conditions when Combining Covalent and Non‐Covalent Synthesis

AbstractThe combination of covalent and non‐covalent synthesis is omnipresent in nature and potentially enables access to new materials. Yet, the fundamental principles that govern such a synthesis are barely understood. Here, we demonstrate how even simple reaction mixtures behave surprisingly complex when covalent reactions are coupled to self‐assembly processes. Specifically, we study the reaction behavior of a system in which the in situ formation of discotic benzene‐1,3,5‐tricarboxamide (BTA) monomers is linked to an intertwined non‐covalent reaction network including self‐assembly into helical BTA polymers. This system shows an unexpected phase‐separation behavior in which an interplay of reactant/product concentrations, side‐products and solvent purity determines the system composition. We envision that these insights can bring us one step closer to how to design the synthesis of systems in a combined covalent/non‐covalent fashion.

Assessment of the solvent-electromagnetic heating-based bitumen extraction technology through techno-economic modelling

Bitumen’s high viscosity makes its extraction a challenging operation. The steam-assisted gravity drainage is a widely used extraction method for bitumen in a deep reservoir, however, it is greenhouse gas (GHG) emission-intensive because of high fossil fuel consumption. There is a lot of interest in bitumen extraction technologies with a low GHG emissions footprint. Solvent-electromagnetic Heating (SEH) is an emerging technology that can lower GHG emissions in oil sands extraction. SEH uses an electromagnetic device and solvent to preheat and mobilize emulsion from the reservoir. SEH eliminates the dependence on condensation heat and therefore the strict requirement of solvent purity. However, few studies have explored its techno-economic feasibility. Unlike studies found in the literature, this study presents a detailed techno-economic assessment, where plant size, operating and economic parameters are evaluated to measure their impacts on the economics of SEH technology. A rigorous steady-state process model of the SEH was developed for a capacity of 25,000 bbl/day of bitumen. The supply cost of dilbit, a mixture of bitumen and diluent, was evaluated. The estimated supply cost is C$56.80/bbl. Taking uncertainty into consideration, this cost ranges from C$55.20/bbl to C$64.40/bbl with median and mean values of C$60.20/bbl and C$59.90/bbl, respectively. Maintenance cost, solvent cost, blending cost, and transportation cost were major contributors to the supply cost of the SEH dilbit. The developed scale factor for SEH is 0.85, which suggests that a large plant capacity will reduce the dilbit cost. The SEH process is cost-competitive with conventional oil sands extraction methods and can be considered as a potential replacement for new greenfield projects. The findings of this study provide insight into the economic performance of SEH, thus can be used for decision-making.

Commercial Spirits for Surfactant-Free Syntheses of Electro-Active Platinum Nanoparticles

The Co4CatTM process is a simple, surfactant-free method to produce colloidal dispersions of precious metal nanoparticles in alkaline mono-alcohols. The synthesis is performed in low-boiling-point solvents and is relevant for industrial production. The robustness of the process is demonstrated by using three different commercial spirits as solvents to obtain Pt nanoparticles. The results demonstrate that careful control of the solvent purity is not needed to achieve the synthesis of stable 2 nm platinum nanoparticle colloids readily active electrocatalysts for energy conversion reactions like the methanol oxidation.

In situ oils/organic solvents cleanup and recovery using advanced oil-water separation system

Removing contaminants from wastewater is critical towards resolving global water pollution problems. However, the variety of oily contaminants composition, and the unsatisfactory performance and efficiency of current separation systems are still big challenges, thus developing efficient and scalable oil-water separation (OWS) methods is needed. Here, the performance of a novel pilot-scale oil-water separator skimmer (OWSS) prototype is fully investigated using an upflow fixed bed column system packed with polypropylene (PP) fibrous sorbent materials for dual continuous OWS and in situ oils/organic solvents recovery. The mechanism of oil sorption by the PP fibrous sorbents, as well as capillary and vacuum assisted oil flow within the inter-fiber voids is fully explored. A series of pilot-scale column experiments were performed with different bed heights (7.5–30 cm) and using different types of oil/solvent in order to determine their influence on the oil flux, OWS efficiency and recovered organic solvent purity. The OWSS provided excellent and stable performance. A trade-off relationship between oil flux and OWS efficiency can be obtained: The maximum flux was attained at the lowest sorbent bed height (7.5 cm), while the maximum OWS efficiency (>99%) was achieved at the highest sorbent bed height (30 cm). The materials’ morphology and wettability were examined showing outstanding stability and recyclability, which demonstrates their efficient integration into the overall OWSS. This study is expected to provide significant insights into the feasibility and scalability of an advanced, environmentally friendly, and relatively cost-effective OWS system, towards promising industrial implementation to overcome large-scale oil spill cleanup and oily wastewater treatment shortcomings.

Electrostatic Stabilization and Characterization of Fine Ground Silicon Particles in Ethanol

Stirred media milling is a common method for the efficient production of nanoparticles. Here the grinding of semi-metallic silicon nanoparticles is presented, which are of special interest as anode material for next generation lithium-ion batteries. Ground silicon particles show an enormous reactivity in water due to particle etching but only surficial oxidization in alcoholic solvents, which inhibits further particle etching. Therefore, the grinding process was realized in ethanol as a solvent in order to avoid particle etching but allow good integrity to a water-based anode production later on. From the application point of view the colloidal stability of silicon nanoparticle suspensions is of great importance, to realize anode coating structures with fine disperse silicon nanoparticles. Hence, this study is focusing on the electrostatic stabilization of the silicon nanoparticles in ethanol, which was characterized by zeta potential and the agglomerate size measurements. These results corresponding to electrostatical interactions are also in good accordance with rheological characterization of the suspensions and theoretical calculations. Additionally, the final metallic silicon content was also of high interest for the application, so that a thermogravimetric analysis procedure was established and evaluated by a chemical pulping procedure according to DIN EN ISO 21068-2. Furthermore the impact of the chosen stabilization additive and the solvent purity on the silicon content are discussed. Finally the process is realized by a pre-grinding step in a planetary ball mill and a fine grinding step within a stirred media mill. With this setup a production route for suspensions with a median primary particle size of less than 150 nm and metallic silicon content above 80 wt.% of the particles is presented. The ground nanoparticles show a surficial oxidized shell with a silicon core and a flake-like shape with crystalline and amorphous regions.

Processing optimization: A way to improve the ionic conductivity and dielectric loss of electroactive polymers

ABSTRACTElectro‐active polymers (EAPs) such as P(VDF‐TrFE‐CTFE) are greatly promising in the field of flexible sensors and actuators, but their low dielectric strength driven by ionic conductivity is a main concern for achieving high electrostrictive performance. It is well known that there is a quadratic dependence of the strain response and mechanical energy density on the applied electric field. This dependence highlights the importance of improving the electrical breakdown EAPs while reducing the dielectric losses. This article demonstrates that it is possible to dramatically increase the electrical breakdown and decrease the dielectric losses by controlling processing parameters of the polymer synthesis and fabrication procedure. As a result, an enhancement of around 70% is achieved in both the strain and blocking force. The effects on the dielectric losses of the polymer crystallinity, molecular weight, solvent purity, and crystallization temperature are also investigated. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1164–1173

Optimization of normal phase chromatographic conditions for lipid analysis and comparison of associated detection techniques

One important challenge in lipid class analysis is to develop a method suitable or, at least adaptable, for a vast diversity of samples. In the current study, an improved normal-phase liquid chromatography (NPLC) method allowed analyzing the lipid classes present in mammalian, vegetable as well as microorganism (yeast and bacteria) lipid samples. The method effectively separated 30 lipid classes or subclasses with a special focus on medium polarity lipids. The separation was carried out with bare silica stationary phase and was coupled to evaporative light scattering detection (ELSD), charged aerosol detection (Corona-CAD®) and mass spectrometry. Solutions are provided to circumvent technical issues (such as pumping solvents of low viscosity, solvent purity, rinsing step). The influence of mobile phase composition and addition of ionic modifiers on the chromatographic behavior of particular lipid classes is documented. A comparison between ELSD and Corona-CAD® confirmed the interest of this later detector for samples with a wide range of concentration of different lipids. Three common atmospheric pressure ionization interfaces were used for coupling the NPLC separation to a LTQ Velos Pro® mass spectrometer. The comparison of the chromatographic profiles showed that atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) are both suitable to detect the different lipid classes whereas APPI allows a better sensitivity for lipids at low-concentration.

Evaluation, prediction and optimization the ultrasound-assisted extraction method using response surface methodology: antioxidant and biological properties of Stachys parviflora L.

To optimize the extraction method using response surface methodology, extract the phenolic compounds, and identify the antioxidant and biological properties of Stachys parviflora L. extracts. Maceration and ultrasound-assisted extraction (UAE) (4, 7, 10 min treatment time, 40, 70, 100 % high-intensity and 60, 80, 100 % (v v-1) methanol purity) were applied to obtain the extracts. SEM was conducted to provide the microstructure of the extracted plant. MICs (colorimetric assay), MFCs (colony diameter), total phenolic content, total flavonoid content, radical scavenging capacity and extraction efficiency were determined. HPLC analysis was applied to measure the existent phenolic compounds. A quadratic model (4 min treatment time, 74.5 % high-intensity and 74.2 % solvent purity) was suggested as the best (TPC: 20.89 mg GAE g-1 d.m., TFC: 6.22 mg QEs g-1 d.m., DPPH IC50: 21.86 µg ml-1 and EE: 113.65 mg g-1 d.m.) UAE extraction model. The optimized UAE extract was generally more effective against Gram-positive microorganisms (MIC: 10-20; MBC: 10-40 (mg ml-1)) than Gram-negative ones (MIC: 40; MBC: >40 (mg ml-1)). Moreover, it (MGI: 2.32-100 %) revealed more anti-mold activity than maceration (MGI: <28.77 %). Explosive disruption of the cell walls, therefore, enhanced extraction yield by acoustic cavitation, was elucidated using SEM. Caffeic acid, tannic acid, quercetin, trans ferulic acid and rosmarinic acid were determined as the phenolic compounds in the optimized extract. RSM optimization was successfully applied for UAE from S. parviflora. The considerable antioxidant and biological properties were attributed to the phenolic compounds.

Boundary lubrication effect of organic residue left on surface after evaporation of organic cleaning solvent

Although samples are visibly clean, organic deposits could have tremendous impacts on tribological measurements and interpretation of friction and wear behaviors. This paper discusses the boundary lubrication effects of invisible residues from organic solvents that have been widely used in tribological studies in ambient conditions. Stainless steel, soda lime glass, and copper substrates were cleaned using UV/ozone treatment or organic solvents such as alcohols where the solvent was allowed to evaporate from the surface. In ball-on-flat tribo-tests, all UV/ozone cleaned samples showed high friction and catastrophic wear immediately upon sliding due to the absence of lubricants at the sliding interface, while samples cleaned by organic solvent experienced low friction and minimal wear for hundreds of reciprocating cycles. Analyses of the surface by atomic force microscopy and vibrational spectroscopy indicated that the solvent cleaning deposits hydrocarbon residue on metal and oxide substrates. This residue is due to trace impurities with low vapor pressures inevitably present in the bulk liquid, regardless of solvent purity, which become concentrated upon vaporization of the high vapor pressure solvent. These results demonstrated that drying after cleaning with organic solvents is equivalent to a dip-coating of low vapor pressure organics onto the sample surface. This dip-coating effect can be avoided if surfaces are cleaned using UV/ozone or if the surface is immediately rinsed with DI water and blow-dried after cleaning with organic solvent. These results indicate that the friction coefficients of the samples with organic residues should not be interpreted with the shear strength model of friction.

Simulation, optimization, and sensitivity analysis of a natural gas dehydration unit

The exploration and production of natural gas are usually accompanied by large amount of water vapor production. In order to prevent serious problems like hydrate formation that would be posed by water vapor molecules it is necessary to remove water from natural gas stream; a process called dehydration. In this study, a natural gas dehydration unit along with its diethylene glycol (DEG) recovery section, located in Iran, is simulated using a steady state flow-sheet simulator. For simulation purposes, a Redlich-Kwong-Soave equation of state with Modified-Huron-Vidal mixing rule (known as RKSMHV2 model) was applied owing to its low absolute average relative deviation percentage (AARD%) compare to the other available models. The primary aim of this research is to study the possibility of optimizing the whole process and performing a sensitivity analysis over the obtained results from the simulation. Volatile organic compounds (VOC) emission, dry gas dew point, solvent loss, and process total duty were chosen as dependent variables of the dehydration process the sensitivity of which were examined by independent variables variations like wet gas molar flow rate, solvent molar flow rate, solvent purity and water content of natural gas. The final results revealed that VOC emission is extremely sensitive to an enhancement in purity or molar flow rate of glycol while for the wet gas and water molar flow rate variations, solvent loss changes are more severe than the other dependent parameters. By taking into account all operational restrictions and assuming dry gas dew point as the key factor for the process optimization; it was revealed that a 10% increase in solvent molar flow rate is applicable in order to reduce dry gas dew point up to 6% without a significant rise in the dehydration unit's total energy consumption and VOC emission.

Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa

Effectively determining masses of proteins is critical to many biological studies (e.g. for structural biology investigations). Accurate mass determination allows one to evaluate the correctness of protein primary sequences, the presence of mutations and/or post-translational modifications, the possible protein degradation, the sample homogeneity, and the degree of isotope incorporation in case of labelling (e.g. 13C labelling).Electrospray ionisation (ESI) mass spectrometry (MS) is widely used for mass determination of denatured proteins, but its efficiency is affected by the composition of the sample buffer. In particular, the presence of salts, detergents, and contaminants severely undermines the effectiveness of protein analysis by ESI-MS. Matrix-assisted laser desorption/ionization (MALDI) MS is an attractive alternative, due to its salt tolerance and the simplicity of data acquisition and interpretation. Moreover, the mass determination of large heterogeneous proteins (bigger than 100 kDa) is easier by MALDI-MS due to the absence of overlapping high charge state distributions which are present in ESI spectra.Here we present an accessible approach for analysing proteins larger than 100 kDa by MALDI-time of flight (TOF). We illustrate the advantages of using a mixture of two matrices (i.e. 2,5-dihydroxybenzoic acid and α-cyano-4-hydroxycinnamic acid) and the utility of the thin layer method as approach for sample deposition. We also discuss the critical role of the matrix and solvent purity, of the standards used for calibration, of the laser energy, and of the acquisition time. Overall, we provide information necessary to a novice for analysing intact proteins larger than 100 kDa by MALDI-MS.

Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa

Effectively determining masses of proteins is critical to many biological studies (e.g. for structural biology investigations). Accurate mass determination allows one to evaluate the correctness of protein primary sequences, the presence of mutations and/or post-translational modifications, the possible protein degradation, the sample homogeneity, and the degree of isotope incorporation in case of labelling (e.g. 13C labelling). Electrospray ionization (ESI) mass spectrometry (MS) is widely used for mass determination of denatured proteins, but its efficiency is affected by the composition of the sample buffer. In particular, the presence of salts, detergents, and contaminants severely undermines the effectiveness of protein analysis by ESI-MS. Matrix-assisted laser desorption/ionization (MALDI) MS is an attractive alternative, due to its salt tolerance and the simplicity of data acquisition and interpretation. Moreover, the mass determination of large heterogeneous proteins (bigger than 100 kDa) is easier by MALDI-MS due to the absence of overlapping high charge state distributions which are present in ESI spectra. Here we present an accessible approach for analyzing proteins larger than 100 kDa by MALDI-time of flight (TOF). We illustrate the advantages of using a mixture of two matrices (i.e. 2,5-dihydroxybenzoic acid and α-cyano-4-hydroxycinnamic acid) and the utility of the thin layer method as approach for sample deposition. We also discuss the critical role of the matrix and solvent purity, of the standards used for calibration, of the laser energy, and of the acquisition time. Overall, we provide information necessary to a novice for analyzing intact proteins larger than 100 kDa by MALDI-MS.

Interfacial synthesis of bisphenol A tetrachlorocyclotriphosphazene from bisphenol A and hexachlorocyclotriphosphazene

Abstract The effect of solvent purity on the synthesis and yield of bisphenol A tetrachlorocyclotriphosphazene (BATCCP) has not been described in the literature. The purpose of this research was to synthesize BATCCP hybrid monomers and to evaluate the effect of solvent purity on the BATCCP production. BATCCP monomers were prepared by an interfacial procedure in a water/toluene system as a function of time with the assistance of a phase transfer catalyst, tetraoctylammonium bromide. 1 H and 31 P NMR confirmed the production of BATCCP monomer by the appearance of chemical shifts at 7.18 and 5.35 ppm in the 1 H NMR and 23.4 and 13.9 ppm in the 31 P NMR, respectively. Distillation of the toluene, not suggested in previous reports of HCCP hybrid synthesis, resulted in an improvement of actual % yield to 40% and stability of the product throughout the 1440 min reaction as confirmed by MALDI, compared with an 11% actual yield at 15 min, decaying to 2% over a 1440 min reaction when the synthesis was performed with ‘anhydrous toluene’ as provided commercially without further distillation.

Effects of experimental conditions on the molecular composition of maltenes and asphaltenes derived from oilsands bitumen: Characterized by negative-ion ESI FT-ICR MS

A vacuum topped Canadian oilsands bitumen (VTB) was subjected to solvent precipitation and subsequently characterized by elemental analysis, gel permeation chromatograph (GPC), 1H-NMR spectroscopy and negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Effects of experimental conditions such as solvent types (n-C5, n-C6, and n-C7), solvent purity, and solvent washing time on asphaltenes yields, bulk composition, and molecular composition of detectable heteroatom compounds in ESI source were determined. Elemental nitrogen and sulfur were enriched in asphaltenes while elemental oxygen had comparable content in maltenes and asphaltenes. Molecular composition of asphaltenes varies with separation conditions. The N1 and O1 species identified by ESI FT-ICR MS were enriched in maltenes. The O2 species exhibited two different double bond equivalents (DBE) distributions and solubility in normal paraffin solvents, indicating two types of molecular structures. Multi oxygen atom containing compounds mainly detected in asphaltenes. Compound class distributions are similar for maltenes derived from n-C5, n-C6, and n-C7, as well as for asphaltenes. The cyclic paraffin impurities in normal paraffin solvents had a significant influence on asphaltenes yields and heteroatom molecular composition. A portion of neutral N1 species and acidic O2 species adsorbed on asphaltenes could be dissolved by increasing washing time. Cautions should be exercised when interpreting the properties and composition of asphaltenes obtained with different experimental conditions.

Optimization of the Water-Insoluble Procedures for USP General Chapter Residual Solvents &lt;467&gt;

The water-insoluble procedures in US Pharmacopeia (USP) General Chapter Residual Solvents <467>, which are based on European Pharmacopoeia procedures, were optimized and modified before their inclusion in the chapter to improve their scope, performance, and ruggedness. The optimized procedures use a static headspace introduction system with a gas chromatograph equipped with a flame ionization detector. This article describes some of the key changes made to the USP published procedures, including use of dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) as the solvent, addition of 5 mL of water and 1 mL of sample (dissolved in DMSO or DMF) to the headspace vial, use of a 3:1 GC split ratio, and use of new matrix-matched system suitability solutions. These procedures were verified with two different active pharmaceutical ingredients--hydroxyzine pamoate and prednisone. In the investigation, the more polar material (hydroxyzine pamoate) showed greater recoveries for the optimized procedures when prepared in DMSO. The less polar material (prednisone) typically had greater recoveries in DMF for the optimized procedures. During experimentation, insights into sample preparation, additional types of headspace instrumentation, solvent purity, and other parameters were also gained.