Effect Of Diluents Research Articles

Effects of Diluents on Physical and Chemical Stability of Phenytoin and Phenytoin Sodium.

The focus of the present work was to investigate compatibility between commonly used diluents and the drug (salt and acid form of the phenytoin). Lactose monohydrate (LMH), lactitol hydrate (LCT), and mannitol (MNT) were selected based on commercial products information of phenytoin sodium (PS) and phenytoin acid (PHT). Binary mixtures of the drug-diluent were stored at 60°C and 40°C/75% RH. Similarly, two commercial products, namely Product-A and Product-B, were also investigated in in-use stability. Color of PS-LMH changed from white to yellowish-brown and pH dropped by 3.4units after 4weeks exposure. FTIR, XRPD, and NIR chemical images indicated disproportionation in PS-LMH and PS-LCT mixtures stored at 40°C/75% RH. Furthermore, PS-LMH also indicated chemical interactions as indicated by distortion of LMH peaks. PHT-diluent mixture did not exhibit any physical and chemical modifications. Product-A changed color, increased weight, dropped pH value, and exhibited disproportionation and chemical reactions. The dissolution of Product-A decreased from 83.3 ± 1.4 to 7.1 ± 4.4% on 8weeks exposure to 30°C/75% RH. On the other hand, Product-B did not change; however, dissolution decreased by 15%. In conclusion, PS showed disproportionation and chemical reactions with LMH. Therefore, LMH should be avoided in PS formulations.

Numerical study of the effect of H2O diluents on NOx and CO formation in turbulent premixed methane-air flame

The interaction of turbulence–combustion inside the flame field is studied in a Launder-Sharma Low Reynolds Number (LS-LRN) k−ε/EDM framework, while suitable coefficients have been utilized in the code. A finite volume method (FVM) with staggered grids was applied to discrete set of governing equations. SIMPLE algorithm is applied with a fine grid resolution. The convective terms are discretized using Power Law Scheme (PLS). The system of governing equations is solved simultaneously using numerical or TDMA finite difference methods (Tri-Diagonal Matrix Algorithm). By implementation of the Zeldovich and Westbrook-Dryer mechanisms, NOx and CO concentrations were obtained, respectively. It is illustrated that the implemented LS-LRN-k−ε/EDM method with the new coefficients by shorter runtimes has very good agreement with previously published experimental measurements. Increasing the H2O diluent at the inlet leads to an increase in the temperature, which increases the NOx and CO near the entrance, but gradually towards the outlet of the combustion chamber. The energy absorbed by H2O leads to a severe decrease in temperature and subsequent reduction in the amount of NOx and CO emissions. With increasing H2O diluent, changes in temperature are not very significant, while changes in pollutants CO and especially NOx, are remarkable. With the increase of H2O diluent, the maximum amount of CO emission displaces towards the inlet of the combustion chamber. However, it should be noted that, at a specific value of H2O diluent, the length of the combustion chamber should not be less than critical value, causing the exhaust of the pollutant with large volume to the environment. After the critical point, the increase in the length of the chamber has little effect on reduction of the pollutant exhaust. However, by increasing the H2O diluent, enclosures with smaller length can be utilized.

The Effect of New Diluents on Motility and Viability of Rabbit Spermatozoa

The Effect of New Diluents on Motility and Viability of Rabbit Spermatozoa

Flammability limits of benzene, toluene, xylenes from 373 K to 473 K and flame-retardant effect of steam on benzene series

Typical benzene series (benzene, toluene, xylenes), while having important applications in chemical industry, are also threatening industrial safety and daily life due to high flammability. In this work, we measured the flammability limits of benzene, toluene, xylenes by ASHRAE method based on E681-09 at elevated temperatures (373 K, 423 K and 473 K). As the temperature increased, the flammable concentration ranges of benzene series expanded. On the basis of flammability limits experimental results, the flame-retardant effect of steam (H2O) on benzene, toluene, o-xylene, m-xylene, and p-xylene were investigated at 423 K separately. These experimental data were correlated with the extended Le Chatelier’s law and compared with theoretical estimations based on adiabatic flame temperature (AFT) method. The experimental results were completely reproduced by the extended Le Chatelier’s law. The lower and upper flammability limits (LFLs and UFLs) of benzene/toluene + H2O agreed well with the estimations, and the upper flammability limits of xylenes + H2O were within acceptable absolute deviation range. The average absolute deviations (AADs) of the lower and upper flammability limits for benzene series + steam between experimental results and optimized estimations were 0.07 % and 0.38 % separately. Moreover, flame-retardant effect of other diluents (N2 and CO2) on benzene series were calculated theoretically, and all the critical flammable ratios (CFRs) were close to 1. The results showed that the flame retardancy on benzene series need to be considered seriously rather than using common diluents.

Effect of burner diameter and diluents on the extinction strain rate of syngas-air non-premixed Tsuji-type flames

The present study focuses on the experimental determination of the global extinction strain rate (ag) for different syngas-air combinations using the Tsuji type configuration. To study the effect of porous burner diameter (D), ag values were obtained for four values of D at atmospheric pressure. The experimentally obtained ag for a given fuel-oxidizer combination decreases with an increase in burner diameter (D). This trend is consistent with the limited data available in the literature for hydrocarbon fuels. Other geometric and flow-field effects namely, (1) plug flow, (2) flow-field blocking by the burner, and (3) heat loss by the flame to sidewalls that can affect ag were also experimentally quantified. The results from this study show that the plug flow boundary condition is always satisfied for oxidizer inlet distance > 2 times the largest porous burner diameter. Burner diameter less than 1/4 times side wall length (as is the case for all burners used in this study) does not significantly modify the flow. Hence, these two flow-field modifications do not affect ag. However, heat loss from the flame to the ambient through the side walls can cause a 4–9 % decrease in ag. Experiments showed that, CO/H2 mixtures diluted with N2 yield 1.6–2.25 times higher ag in comparison to CO/H2 mixtures diluted with CO2. Increasing H2 from 1 to 5 % leads to 2.5–3.8 times increase in ag, compared to 5 to 10 % increase in H2 which leads to only 1.3–1.7 times increase in ag for 70 % of N2 (v/v) in fuel mixture. Global extinction strain rate (ag) increases by 1.5–2.4 times with 10 % increase in CO for fuel mixtures consisting of H2 (1 and 5 % by v/v), CO2 (50, 60 and 70 % by v/v) and N2 (50, 60, 70 and 80 % by v/v). The change in overall reactivity (ωo) due to different diluents is used to quantitatively explain the variation of ag for different fuel compositions. These effects are also qualitatively explained using OH radical concentration change with H2 % in the fuel mixtures.

Effects of Diluents, Saliva and Other Organics on the Microbicidal Activity of Cetylpyridinium Chloride and Povidone-iodine

Povidone-iodine (PVP-I) is used for infection control and preoperative sterilization of the oral and pharyngeal regions. Marketed preparations containing cetylpyridinium chloride (CPC) are used to inhibit growth of oral bacteria. We conducted an in vitro study of the sterilizing effects of these microbicides on 10 oral bacterial strains and fungi related to pneumonia and periodontal disease, after dilution with phosphate-buffered saline (PBS), saliva, and components in saliva. The CPC solution was evaluated at 50 mg/100 mL, which is the concentration used in products. CPC sterilized all strains within 1 minute. Prolongation of the sterilization time associated with dilution was more gradual in comparison to PVP-I solution. CPC sterilized 7 of 10 microbial strains within 3 minutes at 3 mg/100 mL. At 500 mg/100 mL, which is near the upper limit of the concentration that is actually used, PVP-I solution sterilized 7 microbial strains within 3 minutes. However, PVP-I had no sterilization effect when diluted to 100 mg/100 mL or lower. With addition of saliva, PVP-I sterilized 2 microbial strains within 3 minutes at 500 mg/100 mL, whereas CPC solution sterilized 9 microbial strains within 1 minute at 50 mg/100 mL. Our results show that in use influenced by dilution with saliva, CPC is likely to maintain a strong sterilization effect, whereas PVP-I may have a reduced effect.

Method Development and Validation for the Simultaneous Estimation of Ascorbic acid, Phenylephrine HCl, Paracetamol and Levocetirizine HCl using RP-HPLC

An accurate, precise RP-HPLC method was developed for the simultaneous estimation of Ascorbic acid (ASC), Phenylephrine HCl (PHE), Paracetamol (PAR), Levocetirizine HCl (LEV) in tablet dosage form and has been validated as per ICH guidelines. A gradient method was developed using column Aegispak C18 (25cm x 4.6mm, 5μm) and phosphate buffer pH 4.0±0.05, Acetonitrile. The detection was done using wavelength of 220nm. The flow rate was 1.5mL/minute and load volume was 50μL. The retention time of ascorbic acid, phenylephrine HCl, paracetamol, levocetirizine HCl was found to be 2.4±0.1, 5.4±0.1, 10.0±0.1, and 22.7±0.1 respectively. The method was linear in concentration ranges of 50 to 150% and R2 was found to be with in the limit. The result of accuracy was found to be between 98 to 102%. The method was precise as the % RSD was found that NMT 2.0%. Specificity studies reveals no interference in the standard peaks due to placebo and diluent effect. The developed precise method was validated in respect to linearity, range, precision, accuracy, robustness.

Semen cryopreservation in Piaractus mesopotamicus: the effect of different diluents and freezing equipment

Piaractus mesopotamicus (Holmberg, 1887) is a fish native to the Basin of the River Plate and which has great economic importance. In view of this, there has been interest in developing biotechnologies that aim to optimise reproduction in captivity. The aim of this study was to verify the effect of freezing the semen of the pacu using different diluents and freezing equipment. The semen, after pooling, was diluted in the proportion 1:3 (semen: diluent) in two different freezing media, resulting from combining 10% DMSO with Glucose 5% or with ACP-104; it was then cryopreserved in a Dry Shipper or programmable freezer (PF). The samples were later thawed and evaluated for sperm kinetics, membrane integrity and sperm morphology using the Computer Assisted Sperm Analyser (CASA). The data were submitted to ANOVA, and the mean values compared by F-test (P <0.05). There was no interaction between the Glucose 5% or ACP-104 diluents, and the Dry Shipper or PF equipment. However, Glucose 5% showed better results for sperm kinetics (motility: 40.52 ± 7.1%; VCL: 28.53 ± 4.07 µm s-1; VSL: 9.38 ± 3.54 µm s-1 and VAP: 15.24 ± 4.23 µm s-1) compared to ACP-104 (motility: 31.19 ± 3.17%; VCL: 22.76 ± 1.86 µm s-1; VSL: 5.4 ± 1.16 µm s-1 and VAP: 10.06 ± 1.53 µm s-1). It can therefore be concluded that Glucose 5% gives the best results compared to ACP-104, regardless of the equipment used, Dry Shipper or PF, in freezing the semen of P. mesopotamicus.

СВОЙСТВА ТОПЛИВНЫХ ЗОЛ РАЗЛИЧНЫХ ТИПОВ КАК КОМПОНЕНТОВ БИТУМНОЙ ЭМУЛЬСИИ

This paper presents the results of a study of the variability of physico-mechanical and physico-chemical properties, as well as structural features of aluminosilicate technogenic raw materials from wastes of fuel and energy enterprises in the form of various types of ashes as components of bitumen emulsions used in the composition of a hybrid binder (Portland cement - bitumen emulsion) for cement-asphalt concrete. Based on the analysis of the set of characteristics of fuel ashes, the possibility and expediency of their introduction into the composition of bitumen emulsions were determined with the aim of obtaining bitumen layers in the structure of cement-asphalt concrete, allowing to improve its operational characteristics. As a result of the analysis, the most effective diluent additive was identified among the studied technogenic raw materials, which would allow keeping its properties at the stage of introduction into the emulsion, and at the stage of forming the structure of the final composite to provide the desired properties.

Influence of Coconut Powder Water-Based Conservation Medium (APC-102c) for Maintaining Mitochondrial Activity of Cryopreserved Ram Sperm

Background: Semen extenders are required to protect and preserve semen, and the development of suitable extenders is key for artificial insemination. Although the use of Tris-based diluent is widespread, new diluents such as powdered coconut water have been developed for better sperm protection. One way to evaluate the effectiveness of diluents is through microscopic analyses that evaluate sperm motility, vigor, and concentration. However, these analyses are limited, and may not provide accurate results. New evaluation techniques have been studied, and one of the tests that can be used to add reliability to these analyses is mitochondrial activity evaluation, which can sum all the parameters, and provide a more accurate evaluation. Thus, the present study aimed to evaluate the efficacy of ACP-102c in cryopreserved ram semen.Materials, Methods &amp; Results: Five semen samples were collected from two ram breeders using artificial vagina (n = 10). Each ejaculate was divided into the following two treatments: T1 - ACP-102c + 20% egg yolk + 7% glycerol and T2 - TRIS + 20% egg yolk + 7% glycerol. Extended semen samples were then packed in 0.5 mL plastic straws, subjected through the refrigeration curve up to 4°C (0.35° C/min), and equilibrated for 2 h at 4°C. Subsequently, the straws were placed at 4 cm above liquid nitrogen level (-60°C) for 15 min, immersed, and then finally stored in the liquid nitrogen at -196°C. Both fresh and thawed samples were evaluated for total and progressive sperm motility using conventional microscopy (40x), and the same evaluator on each occasion. For plasma membrane integrity (IMP), the smear staining technique with the Eosin-Nigrosin staining was used; 200 sperms were counted and classified as whole (unstained) and unhealthy (stained). Mitochondrial activity was evaluated using a cytochemical technique based on the oxidation of 3,3'-diaminobenzidine (DAB); 200 sperms were counted, and classified into four classes (I, II, III, and IV) according to the degree of coloration of the intermediate part. Fresh semen showed no significant difference (P &gt; 0.05) between treatments with respect to motility parameters; however, T2 showed significantly inferior results regarding plasma membrane integrity. After thawing, T2 was significantly higher in sperm motility parameters compared to T1. The mitochondrial activity and plasma membrane integrity parameters did not show any significant difference between the treatments.Discussion: The TRIS-based diluent showed higher motility values than ACP-102c; however, motility rates in ACP-102c diluent, although lower, are considered satisfactory for insemination, which requires semen with minimal progressive motility of 30%. Notably, the cryopreservation protocol used in this study is the standard for TRIS-based diluent, and it is known that the optimal rate of refrigeration and cryopreservation may differ according to the composition of the storage medium; therefore, we may assume that the protocol used is not yet appropriate for the ACP-102c diluent, and further studies are required. IMP is an essential attribute for fertilization, and cryopreservation can affect the plasma membrane as observed in this study. Cryopreserved semen reduced the percentage of class I mitochondrial reaction sperms in both treatments, demonstrating that cryopreservation affects the mitochondrial activity of the intermediate portion of the sperm; however, there was no difference between treatments in thawed semen. Thus, we concluded that the ACP-102c conservation medium maintains seminal quality after thawing, and it can be used in artificial insemination processes.

Effect of mixed diluents during thermally induced phase separation process on structures and performances of hollow fiber membranes prepared using triple-orifice spinneret

In this study, polyvinylidene fluoride hollow fiber membranes were prepared using a triple-orifice spinneret in thermally induced phase separation. A solvent, propylene carbonate (PC), was extruded through the outermost layer of the spinneret. Through the use of this method, all the membranes were developed an entirely porous surface with similar pore size and porosity. Using mixed diluents with different concentrations of diphenyl carbonate and PC, the membrane bulk structures were controlled from an entirely bicontinuous network, a combination of bicontinuous and spherulitic structures, to an entirely spherulitic structure. The tailored bulk structures showed significant effects on the permeability, rejection, and mechanical strength of the membrane. Furthermore, the membrane sub-layer structure was modified to form different types from the composite-like structure of the combination of the spherulites and bicontinuous network to entirely spherulites, which controlled the membrane permeation stability within an extensive range of 6% to nearly 100%. A change in the polymeric dope solution phase diagram, as well as the interfacial behaviors of the polymeric dope solution and extruded PC, played important roles in appropriately tailoring membrane structures and performances. These novel and solid findings regarding the connections between structures and performances provide an advisable venue for the design of hollow fiber membranes with satisfactory performances.

25 A preliminary study of the effects of breed and nanowater as extender diluent on ram semen characteristics post-thawing

This study examined the effect of genotype and extender diluent on the characteristics of frozen-thawed ram semen. Twenty ejaculates collected from 10 rams aged 4-12 years (2 Polish Lowland (PON), 4 synthetic line BCP (Berrichon du Cher×Charolais×PON/Polish Merino), and 4 SCP (Suffolk×Charolais×PON/Polish Merino) in mid-breeding season were divided into six equal portions each and frozen in semen extender prepared by mixing commercial Triladyl extender (MiniTub GmbH) with deionized water (Aqua Purificata, Prolab) or nanowater (NW; deionized water declusterized in a cold plasma generator for 15, 30, 45, 60, or 90 minutes (15’, 30’, 45’, 60’, or 90’, respectively); Nanotechnology Systems) and Gallus domesticus egg yolk (1:3:1 vol/vol/vol). All semen samples were evaluated for progressive motility (Sperm Class Analyzer) and sperm morphology (Nikon Eclipse 80i microscope, Nikon Corp.). In addition, the ex situ survival time at 37°C and extender content of ALT (alanine transferase), ALP (alkaline phosphatase), and aspartate aminotransferase were measured, and the numbers of apoptotic, necrotic, and live spermatozoa were determined post-thawing with flow cytometry (BD Accuri™ C6 Plus, Becton Dickinson). Data were analysed by two-way analysis of variance and least significant difference test (SigmaPlot, Systat Software Inc.). The PON exceeded (P&amp;lt;0.05) SCP rams in the occurrence of mid-piece and double tail defects using NW30’ and NW45’ extenders. The proportion of spermatozoa with proximal droplets was greater (P&amp;lt;0.05) in PON than in SCP or BCP rams with NW15’ and NW30’ extenders, respectively, but the percentage of sperm with detached heads was greater (P&amp;lt;0.05) in BCP and SCP compared with PON using NW15’ extender. Overall, spermatozoa in PON rams’ semen had survival times greater by 25-50min (P&amp;lt;0.05) compared with those for semen from BCP and SCP synthetic lines. The ALT levels were significantly elevated in SCP compared with PON and BCP rams only in NW90’ extender. The numbers of necrotic spermatozoa were greater (P&amp;lt;0.05) in SCP and BCP compared with PON rams, and the numbers of apoptotic spermatozoa were greater (P&amp;lt;0.05) in BCP than in SCP rams with NW45’, NW60’, and NW90’ extenders. Live spermatozoa were more prevalent (P&amp;lt;0.05) in PON than in BCP rams in NW45’ extender post-thawing. To summarise, semen from PON rams had higher survival times and fewer spermatozoa with detached heads but more mid-piece defects and sperm with double tails post-thawing compared with BCP and SCP breeds. The number of necrotic cells was greater in semen from BCP and SCP rams compared with PON. It can be concluded that breed-related differences in post-thaw sperm morphology were apparent in extenders containing NW15-60’, whereas the variations in cell necrosis/apoptosis were primarily seen with the use of NW45-90’ extenders.

Investigation of the effect of reactive diluent on the properties of coatings based on unsaturated polyesters

Currently, the biggest share of paints and varnishes intended for painting internal surface of metal canning containers is accounted for by compositions containing epoxy oligomers. Despite the fact that such materials allow to obtain coatings with good adhesion to metal substrates, sufficient chemical resistance and elasticity, they have one significant drawback, which is due to the main component of epoxy resins – bisphenol A. Due to the well-known negative effects of bisphenol A on human health, the use of such materials is currently limited. Promising replacement of these materials are composites based on polyester resins. However, it should be mentioned that the disadvantage of polyester varnishes intended for canning containers is the low resistance of coatings to sterilization when laying food products in containers. The main reason for such low resistance is a relatively high content of ester groups in the structure of these polymers, characterized by low water, alkali and limited acid resistance. To increase the resistance of such coatings, we proposed to introduce fragments of unsaturated monomers (capable of homopolymerization under the conditions of polyester compositions (intended for can-coating) curing) into the composition of their polymer macromolecules. These fragments should create an additional steric hindrance for diffusion to ester groups of destructive molecules of aggressive media and ensure the durability of coatings in general. Synthesis of such polyesters is a typical polycondensation process, and to accelerate it, it is advisable to use various catalytic systems.

Effect of CO2 diluent on the formation of pollutant NOx in the laminar non-premixed methane-air flame

In this paper, the effects of changes in the concentration of diluent CO2 in methane and air fuels are investigated. A finite volume method (FVM) with staggered grids is used for numerical solution. Equations of continuity, momentum, energy, ideal gas state and kinetic equations with thermodynamic and thermo-chemical information of chemical species are solved using the numerical method of SIMPLE. The convective terms are discretized using Power Law scheme (PLS). The under-relaxation factor dependent on temperature has been utilized to solve the chemical kinetic equations. In this research, by increasing the diluent mass fraction, the mass fraction of the fuel is diminished to the same extent. Therefore, the sum of the diluent and fuel mass fraction values remains constant. The results depicted that as the amount of CO2 diluent in the fuel increases, the total lift-off height and flame length decreases linearly, and the maximum temperature in the combustion chamber becomes smaller than that at the inlet of the chamber. When the concentration of CO2 increases in the fuel, the temperature changes become negligible at the inlet of the combustion chamber. By using the CO2 diluent, shorter combustion chambers can be used. While the diluent is used, the increase in the length of the combustion chamber will not have any effect on the NOx emissions reduction. Therefore, the more concentration of the diluent is used, the smaller the combustion chamber can be selected. Moreover, by increasing the diluent, NOx pollutant decreases in the combustion chamber.

Adiabatic laminar burning velocities of C3H8-O2-CO2 and C3H8-O2-N2 mixtures at ambient conditions-PART I: Experimental and numerical study

This study and its companion paper presents a comprehensive study of laminar premixed flames of propane under oxy-fuel and oxygen-enrichment conditions for the first time. Laminar burning velocities were measured with the heat flux method at ambient conditions within an equivalence ratio of 0.6–1.6. The experimental results are discussed by comparison with modeling results from five detailed kinetic mechanisms. All models predicts the correct tendency of laminar burning velocities varies with equivalence ratios but only the UDEL model predicts the accurate laminar burning velocities under O2-CO2 atmosphere. The laminar burning velocities of C3H8-air and C3H8 + 0.3O2 + 0.7CO2were selected as reference values SL0, a new correlation SL/SL0=(1+αYenr+βYenr2) was obtained from the simulations and validated with experiment results. Good agreement between the correlation predictions and experimental results indicating that it is useful to predict SL in the range of this work. Part II will discuss the global flame parameters and the mechanisms of dilution, thermal and chemical effects of diluents on the laminar burning velocities.

Investigation of flame characteristics of hydrogen jet issuing into a hot vitiated nitrogen/argon/carbon dioxide coflow

Fundamental characteristics of hydrogen flame in diluted atmosphere may have important guiding value for controlling the operation of argon-circulated hydrogen engines. In this paper, the impact of thermal-atmosphere (T ≥ 940 K, N2/O2, Ar/O2 and CO2/O2) on the flame characteristics of hydrogen jet were investigated experimentally and numerically based on a controllable active thermal-atmosphere burner. The effects of different diluents on flame liftoff height and luminosity were quantitatively analyzed and the different luminosity of the hydrogen jet flame under different dilution gas atmosphere was explained with the chemical reaction kinetics. Different critical temperatures exist in different atmospheres. The flame luminosity is in the increasing order of CO2/O2-, Ar/O2- and N2/O2-atmosphere. The analysis speculates that CO2* is generated in the flame of CO2/O2-atmosphere. The difference in axial velocity and mixture fraction under different dilution gas atmospheres is mainly influenced by the thermal atmosphere and the physical properties of the dilution gas, which also has a great influence on the jet before the autoignition occurs.

Effects of Diluents on the Separation of Minor Actinides from Lanthanides with Tetradodecyl-1,10-phenanthroline-2,9-diamide from Nitric Acid Medium.

To investigate the effective separation of actinides (Ans) from lanthanides (Lns), single-stage batch extraction experiments were performed with a novel extractant, tetradodecyl-1,10-phenanthroline-2,9-diamide (TDdPTDA) with various diluents such as 3-nitrobenzotrifluoride (F-3), nitrobenzene, and n-dodecane for Am, Cm, and Lns. The extraction kinetics with TDdPTDA was rapid enough to perform continuous extraction experiments using mixer-settler extractors. The slopes of the distribution ratio versus the TDdPTDA concentration and the distribution ratio versus the nitric acid concentration were similar for F-3 and nitrobenzene systems, but different from the n-dodecane system. These differences were attributed to the characteristics of the diluents. This study revealed high distribution ratios of Am (DAm) and Cm (DCm) for TDdPTDA, with the high separation factors (SFs) of Am from Lns enough for their separation.

Impregnated Type Sorbents for Pb2+ Recovery from Neutral and Acidic Solutions

Synthetically convenient method for preparing phosphoryl podand 1,8-bis[2-(diphenylphosphorylmethyl)phenoxy]-3,6-dioxaoctane (L) has been developed. Recovery of Pb2+ with impregnated type sorbents was studied, the sorbents contain isodentate organic ligands—phosphoryl podand L and crown ether (4,4',(5')-di(tert-butyl)dicyclohexyl-18-crown-6)—as extractants. A sorbent based on the phosphoryl podand quantitatively extracts lead from neutral solutions (R = 98.4%) and does not recover it from acid solutions. On the contrary, the sorbents based on 4,4',(5')-di(tert-butyl)dicyclohexyl-18-crown-6 do not extract lead from neutral media and efficiently adsorb it from nitric and hydrochloric acid solutions (R = 90% from 3 M nitric acid solutions and R = 73.2% from 2 M hydrochloric acid solutions). Effect of diluent and support type, support pretreatment procedure, impregnation temperature and time, and solvent for support impregnation on lead sorption with sorbents based on 4,4',(5')-di(tert-butyl)dicyclohexyl-18-crown-6 have been studied.

Reactive extraction: a promising approach to separate protocatechuic acid.

3,4-Dihydroxybenzoic acid, commonly known as protocatechuic acid, is a naturally occurring phenolic compound, being the active component of many medicinal and edible plants. The in vitro and in vivo studies of protocatechuic acid conclude that it possesses many pharmacological properties. Protocatechuic acid, present in waste streams of food processing industries, is considered a phenolic pollutant. Owing to its bactericidal properties and in order to maintain the standards of disposal, its removal from the waste streams is necessary. Protocatechuic acid finds applications also in bioplastics, polymers, and also bio-based active films to improve food preservation. Its direct extraction from plant secondary metabolites possesses many difficulties. Recently reports of protocatechuic acid production by several Bacillus species are present in literature. For the retrieval/removal of protocatechuic acid from aqueous streams, methods like adsorption, O3/UV or H2O2/UV, and microbial degradation are in practice. For the retrieval of carboxylic acid from fermentation broths and aqueous streams, reactive extraction by the use of specific extractants has been found to be a most suitable method owing to its several advantages. The present paper is focused on the separation of protocatechuic acid by reactive extraction as a promising approach. The parameters needed for the design such as distribution coefficient, water co-extraction, physical and chemical extraction, effect of initial acid concentration, diluents, extractant, and extractant concentration have been discussed.

Effect of reactive diluent on gas separation behavior of photocurable acrylated polyurethane composite membranes

ABSTRACTIn this study, the effects of the type and content of reactive diluents on the permeation/separation of carbon dioxide/nitrogen (CO2/N2) through acrylate‐terminated polyurethane (APU)‐acrylate/acrylic diluent (APUA) composite membranes was investigated. A series of APUs based on poly(ethylene glycol) (PEG)‐1000 g mol−1, toluene diisocyanate, and 2‐hydroxyethyl methacrylate was synthesized and then diluted with several reactive diluents. The results obtained from differential scanning calorimetry (DSC) and Fourier transform infrared analyses showed that the microphase interference of hard and soft segments increased with increasing reactive diluent content. Furthermore, with increasing alkene double bond of reactive diluents, the degree of phase separation increased, which might be due to the higher gel content of APUAs. APUAs were used as top selective layer on PS/PSF as the support layer to obtain composite membrane. Field emission scanning electron microscopy micrographs revealed that APUAs penetrated into the support layer, leading to strong interfacial adhesion between APUA and support layers. The gas permeation experiments indicated that the gas permeability decreased, while the CO2/N2 selectivity increased with increasing reactive diluent content due to the enhancement of crosslinking density of APUAs. Moreover, the reactive diluent with high polarity, for example, acrylonitrile monomer, exhibited higher CO2/N2 selectivity due to the improvement in solubility of CO2 in APUA, while the permeability was retained compared with other reactive diluents. The thickness of APUA selective layer exhibited expectedly opposite effect on permeability and selectivity; however, the increment in selectivity is higher than the reduction in permeability when the thickness decreased from 50 to 10 μm. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48293.