Solvent Residence Time Research Articles

Comparative extraction of cannabinoids and terpenoids from Cannabis sativa L. using three solvents

AbstractOrganic solvents of diethyl ether and pentane were tested against ethanol for the extraction of terpenoids and cannabinoids from hemp inflorescence. It is not well known how pretreatment of grinding and extraction conditions, that is, number of extractions, temperature, and solvent residence time affect extraction yield and product compositional profiles, so these were examined in this study. As a general trend, diethyl ether and pentane had better selectivity towards the terpenoids and cannabinoids compared to ethanol. It was found that even though grinding to reduce the particle size of the inflorescence did not dramatically increase the total extraction yield, it increased the yield of the first extraction as well as the content of terpenoids and cannabinoids in the extract. Extraction residence time trial revealed the benefit of shorter time and the different behavior of the two classes of compounds. Increasing the extraction temperature from 4 to 21°C improved the total extraction yield by all three solvents, however, no additional improvement was seen at 30°C. To achieve high concentration of the bioactive compounds in the extract, multiple extraction at 21°C with short residence time, such as 15 min, are preferred for the solvents tested, and an extract having about 6% terpenoids and 59% main cannabinoids was obtained using pentane. This systematic study provides a guide to commercial processing optimization and directions for further investigation.

Modeling and optimization of ionic liquid-based carbon capture process using a thin-film unit

Post-combustion CO2 capture is an effective solution for reducing CO2 emissions. Ionic liquids (ILs) have been proposed as a promising class of absorbents for CO2 capture due to their superior physicochemical properties. As ILs are expected to be, at least initially, costlier than conventional amine solvents, the economic impact of thermal degradation can be more significant for IL-based processes than for conventional systems. In this work, we introduce an advanced IL-based carbon capture process design using a thin-film unit under vacuum to regenerate the solvent. Using this new configuration, the regeneration system can operate at lower temperatures and the solvent residence time can be significantly reduced, minimizing IL absorbent losses due to thermal degradation. We conduct a detailed, rate-based analysis of the impact of thermal degradation kinetics on the economic performance of the proposed process. A comparison to a conventional flowsheet configuration is also presented.

Supercritical carbon dioxide extraction of Calendula officinalis: Kinetic modeling and scaling up study

The extraction of marigold (Calendula officinalis) oleoresin with supercritical carbon dioxide SCCO2 was carried out in a small scale extraction vessel (2.7×10−4m3) studying different extraction pressures (14, 24 and 34MPa) and different flow rates (15, 30 and 45gmin−1) at 313K. Then, using semi-empirical engineering scaling criteria (constant solvent lineal velocity or constant solvent residence time) and the Broken and Intact Cell (BIC) model, the scaling up to larger extraction vessels (1.35×10−3m3 and 5.16×10−3m3) was theoretically investigated.According to the BIC model, by keeping constant the CO2 residence time in the different size vessels a good reproduction of the kinetic behavior should be obtained. Nevertheless, experimental results did not confirm model predictions, and in fact none of the scaling criteria studied resulted adequate in the marigold supercritical extraction scaling up. Thus, using all the experimental overall extraction curves obtained, a new specific correlation was developed between the Schmidt number (Sc), CO2 mass flow, bed geometry and the supercritical mass transfer coefficients kYA with a good fit (R2=0.9767) for scaling up the supercritical extraction of marigold.

Integration of Chemical Physics and Ab Initio Models for Application to Li-Ion and Na-Ion Electrolytes

Electrolytes play a critical role in performance, safety, cost, and life of battery systems. Based on publications and patents alone, an enormous amount of research funding is spent each year investigating new or existing electrolyte systems. Electrochemical energy storage devices such as Li-ion cells and other emerging cell chemistries (e.g., Na, Mg) comprise a multi-billion dollar market that is projected to have greater than linear growth in coming decades to surpass $20B USD per annum. This collective emphasis within academic and market sectors calls for computational tools that can economically accelerate selection and characterization of advanced electrolyte systems. The focus of this work is to demonstrate value through intelligent combination of chemical physics models with ab initio techniques such as DFT. A logical target is electrolyte systems for Li-ion and Na-ion systems, the latter being an area of increased interest in light of its economic potential. Recent refinement and extension of chemical physics modeling to multi-component electrolyte systems has produced tools of unequaled speed and high accuracy. The Advanced Electrolyte Model (AEM, R&D 100 award, 2014) is an example of such a molecular-based tool that has been successfully applied to predict a wide spectrum of molecular and macro-scale properties for battery electrolytes. AEM employs a “static model” approach under the NPNRAMSA basis1, wherein aspects of key interactions such as ion solvation are defined through time averages that incorporate solvent residence times around ions and configuration-dependent distance-of-approach of solvents (ligands) to ions. Only reference values are needed for such averages within AEM, akin to “standard state” values. DFT and MD are logical starting points for such averaged or optimized quantities, as they yield rich information covering configurational and statistical aspects of molecular interactions. The challenge then is to standardize the computational “hand-shake” between DFT/MD and AEM. Two parameters are of primary interest in this model integration exercise. The first is the relative coordination between solvent molecules and an ion in terms of solvent alignment. This parameter has much influence on the effective size of the solvated ion under faradaic transport conditions. Expectedly, solvent alignment will be sensitive to the true solvation number at the salt concentration of interest, accounting for steric factors and field effects. The second parameter of interest is the average solvent residence time of a solvent in the immediate proximity of an ion (e.g., primary solvation shell), which reflects the relative strength of association between solvent and ion. Both of these parameters can be approximated by looking at energy-optimized configurations with representative populations of members (DFT, e.g. ref [1]) and by tracking pair correlation quantities over the simulation timeline (MD). We will present examples of such information and their use within AEM for Li-ion or Na-ion electrolytes such as organic carbonates with LiPF6 or NaPF6. A computational tool developed for materials will be confirmed as robust for more widespread use when it is amenable to investigating a diversity of material targets. We consider the comparison of Li-ion and Na-ion systems to gain understanding of fundamental differences that would influence electrochemical cell behavior. In general terms, it is anticipated that since sodium is typically less solvated than lithium in solution (due to its lower surface charge density) as seen in Fig. 1 for aqueous systems, then we could exploit this attribute to design electrolytes of lower viscosity, since viscosity is dependent in part to the structure in solution, of which ion solvation is a strong contributor in electrolytes [2] (while this concept is demonstrated for aqueous systems in Figs. 1 and 2, our electrolyte targets in the battery space will be non-aqueous). Having lower viscosity will provide a distinct benefit at lower temperatures, where battery electrolytes exhibit high viscosities that impact battery power and pulse duration [3]. Thus, we seek those instances where Na-ion electrolytes could provide superior conductivity at low temperatures, as compared to Li-ion systems. This work is sponsored by the Laboratory Directed Research and Development Program at the INL, under management of the Battelle Energy Alliance, LLC. 1. M. T. Benson, M. K. Harrup, K. Gering, Computational and Theoretical Chemistry 1005 (2013) 25–34. 2. K. L. Gering, Electrochim. Acta, Vol. 51, 3125 (2006). 3. K. L. Gering, ECS Transactions, Vol. 1 (26), 119 (2006). 1 Non-primitive, non-restricted associative mean spherical approximation. Figure 1

Optimization of Solvent Extraction of Parinari polyandra Benth Seed Oil Using Response Surface Methodology

Parinari polyandra B. seed is a potential source of oil with relatively high oil yield. Optimizing the extraction process of the oil will enhance its economic and industrial relevance, providing useful information for would be investors. Aims: This work is aimed at extracting oil from the seeds of Parinari polyandra B . by using solvent extraction method. The process was optimized by using response surface methodology to determine the effect of four sets of parameters corresponding to optimum oil yield. Methodology: Parinari oil was extracted using n-hexane and petroleum ether as solvents, Central Composite Design was used in the design of the 40extraction experimental runs. The effects of solvent residence time (A), temperature (B), solid/solvent ratio (C) and solvent types (D) on the yield of Parinari seed oil was studied using response surface methodology.

Efficient “total” extraction of perfluorooctanoate from polytetrafluoroethylene fluoropolymer

To determine the optimum conditions for the complete extraction of perfluorooctanoate (PFO) from polytetrafluoroethylene fluoropolymers, sample preparation and pressurized solvent extraction (PSE) conditions were investigated. Solvent extraction temperature, solvent residence time, relaxation time between extractions, and the effects of heating before PSE showed that methanol at 150 degrees C extraction temperature and a 12 min solvent residence time were the most efficient conditions. Preheating the polymer before extraction at 150 degrees C for 24 h significantly enhanced the quantity of PFO removed. Heating above 150 degrees C resulted in loss of PFO. PFO was determined by liquid chromatography with tandem mass spectrometry.

Molecular dynamics simulation of the antimicrobial salivary peptide histatin-5 in water and in trifluoroethanol: a microscopic description of the water destructuring effect.

The results of 520 ps molecular dynamics simulation of histatin-5, a small peptide present in human saliva and possessing antimicrobial activity, dissolved in water and in 2,2,2-trifluoroethanol, are reported. The simulations indicate that histatin-5 is destabilized in water and begins to unfold after 250 ps, while in organic solvent it maintains a regular secondary structure throughout the trajectory. Analysis of the peptide-solvent hydrogen bonds indicates that 2,2,2-trifluoroethanol is a poorer proton acceptor than water. The fluorine atom of the alcohol is almost never engaged in a hydrogen bond and the organic solvent interacts mainly with the peptide through its hydroxyl group. For some residues analysis of the solvent residence time indicated longer values for 2,2,2-trifluoroethanol than for water. The most striking difference is related to the number of times the solvent enters and leaves the first coordination shell of the peptide. This value was more than one order of magnitude higher for water than for the alcohol, suggesting that this may be the main cause of alpha-helix destabilization perpetrated by water.

The Wizard Lake Vertical Miscible Flood Solvent Bank Redesign Concept

Abstract The Wizard Lake D-3A Pool has been undergoing a tertiary hydrocarbon miscible flood (HCMF) since 1983 after completing primary production (1951 - 1967) and a secondary HCMF (1969 - 1983). The operation is comprised of three solvent injectors, four push gas injectors, and 42 production wells. Fresh solvent injection (2,500 m3/day) was initiated in 1991 to make up for significant solvent coning and changed the flood design from a vertical flood controlled by longitudinal diffusion to a horizontal flood dominated by transverse diffusion. Recycling in this case also allows the old propane-plus bank to be replaced by a more economical ethane-plus blend. Under solvent recycling, the mixing zone would be stabilized (balanced injection and withdrawal) with its thickness increasing from zero at the injector to the maximum at the producer. The design problem is thus reduced to finding the solvent residence time at each producer and the corresponding minimum bank thickness needed to maintain miscibility. The 1D diffusion equation coupled with miscibility data was used to calculate the required bank thickness and a full field 2D streamline model was used to predict the solvent residence times in this study. New solvent bank thickness design curves were generated by merging the residence times and the minimum miscible bank thickness data. Operating strategies based on the new design curves can potentially reduce the 1994 solvent bank size of 5.5 million reservoir cubic metres (rm3) to 3.0 million rm3. The concept applied in Wizard Lake can be extended to other miscible floods that involve solvent recycling. TABLE 1: Wizard Lake solvent bank design history. Background The Wizard Lake D-3A Pool is a dolomitized carbonate reef with a current estimated original-oil-in-place of 62.4 million m3. Reservoir pressure was decreased from 15.65 to 12.95 MPa during primary production. Prior to the secondary miscible flood (1968), water was injected to repressurize the reservoir to 14.80 MPa. At this time, the water-oil contact rose to 1,201 m sub-sea (mSS) from its initial position of 1,229.6 mSS. A first-contact miscible (FCM) propane-plus solvent and a 95 ﹪ methane push gas were injected to sustain a vertical miscible flood from 1969 to 1983. The solventoil contact reached the 1,201 mSS depth by 1983 and a new approval was granted to extend the flood to capture the tertiary oil trapped between the 1,201 and 1,229.6 mSS levels. This stage is known as the tertiary extension phase and the solvent was changed to an ethane-plus blend. Figure 1 shows a well map of the Wizard Lake D-3A Pool. Table 1 chronicles the history of the solvent bank design for the Wizard Lake flood. Extensive solvent coning commenced in 1991 (∼ 3:1 solvent to oil ratio). The produced solvent was purified and reinjected in order to maintain solvent bank integrity. Updated geological data indicated that the targeted reservoir had a lower porosity than was estimated originally. Due to solvent re-injection, the reservoir flow became largely horizontal with solvent mixing controlled by transverse diffusion. These events prompted the questioning of the original design assumptions and led to a redesign of the flood in 1994.

Molecular dynamics simulation of solvated azurin: correlation between surface solvent accessibility and water residence times.

A system containing the globular protein azurin and 3,658 water molecules has been simulated to investigate the influence on water dynamics exerted by a protein surface. Evaluation of water mean residence time for elements having different secondary structure did not show any correlation. Identically, comparison of solvent residence time for atoms having different charge and polarity did not show any clear trend. The main factor influencing water residence time in proximity to a specific site was found to be its solvent accessibility. In detail for atoms belonging to lateral chains and having solvent-accessible surface lower than approximately 16 A(2)a relation is found for which charged and polar atoms are surrounded by water molecules characterized by residence times longer than the non polar ones. The involvement of the low accessible protein atom in an intraprotein hydrogen bond further modulates the length of the water residence time. On the other hand for surfaces having high solvent accessibility, all atoms, independently of their character, are surrounded by water molecules which rapidly exchange with the bulk solvent. Proteins 2000;39:56-67.

Mechanism of supercritical fluid extraction of coal.

This paper describes the mechanism of supercritical toluene (or toluene–tetralin mixture) extraction of coal. The effects of solvent power and solvent residence time in the cell on conversion and liquid yield were examined by using a two-stage extraction method: extraction at various conditions followed by high-solvent power extraction. The effect of tetralin addition on supercritical toluene extraction was also investigated by this method. Furthermore, in situ ESR measurement was conducted to evaluate the variation of radical concentration during supercritical fluid extraction. From these detailed analyses the effects of the solvent power of supercritical fluid on the reactions during extraction, namely on decomposition and polymerization of the primary products from coal decomposition, and on stabilization of the radicals through hydrogen transfer reaction were evaluated.

Column fractionation of partially stereoregular poly(propylene oxide)

A column packed with glass beads has been used to fractionate partially stereoregular poly(propylene oxide) (PPO). PPO was first crystallized onto the glass beads from isooctane solution by stepwise lowering the column temperature. Each layer of PPO, which was deposited at different temperature ranges, was extracted by washing the beads with several columns full of isooctane. Thus several fractions differing in both stereoregularity and molecular weight were obtained by progressively increasing the extraction temperature and the solvent residence time in the column. It is concluded that in the procedure described above PPO can be fractionated on the basis of structural and steric regularity. The observed steady increase in the molecular weight of fractions with extraction temperature was interpreted as being due to the fact that the stereoregularity of chains increases with their molecular weight.