341. Passive Monitors Performance Under Fluctuating Solvent Concentration and Multiple Solvent Presence

2004 ◽  
Author(s):  
A. Bejan ◽  
M. Morgan ◽  
L. Monteith ◽  
G. van Belle
Keyword(s):  
Solvent Concentration

Catalytic hydrogenation of binary and ternary mixtures of unsaturated substances in the liquid phase on platinum

1979 ◽  
Vol 44 (8) ◽  
pp. 2378-2383 ◽  
Author(s):  
Libor Červený ◽  
Radka Junová ◽  
Vlastimil Růžička
Keyword(s):  
Liquid Phase ◽  
Binary Mixtures ◽  
Silica Gel ◽  
Catalytic Hydrogenation ◽  
Ternary Systems ◽  
Ternary Mixtures ◽  
Unsaturated Alcohol ◽  
Solvent Concentration ◽  
Binary And Ternary Mixtures ◽  
Hydrogenation Selectivity

Hydrogenation of olefinic substrates in binary and ternary mixtures using 5% Pt on silica gel as the catalyst was studied in normal conditions in the liquid phase with methanol or cyclohexane or in solvent-free systems. The effect of the solvent concentration on the selectivity of hydrogenation of the unsaturated alcohol-olefin binary mixtures was investigated. In ternary systems of unsaturated substrates, the effect of each of the substrates on the selectivity of hydrogenation of the remaining two substances was examined. Another system was found in which a jump change of the hydrogenation selectivity occurred on the vanishing of the fastest reacting substance.

Solvent diffusion mechanism of PMMA/ acetone coated glass fiber fabric during curing process

2021 ◽  
pp. 152808372110362
Author(s):  
Zhenrong Zheng ◽  
Yuejiao Bi ◽  
Lihuan Tong ◽  
Yalan Liu
Keyword(s):  
Glass Fiber ◽  
Diffusion Mechanism ◽  
Coating Film ◽  
Curing Process ◽  
Curing Time ◽  
Solvent Concentration ◽  
Solvent Diffusion ◽  
Coated Glass ◽  
Drying Model ◽  
Fiber Fabric

Fabric it is not an impermeable substrate because of fiber porosity. To study the solvent diffusion mechanism of coated fabric in the curing process, the drying model of PMMA/acetone coated glass fiber fabric was established. This drying model was verified by confocal Raman spectroscopy. Finally, the impact of fabric structure, thickness and porosity on the solvent diffusion process in coated fabrics was studied by the model. It was shown that the predicted solvent concentrations by the model were consistent with the experimental values. This model can be used to quantitatively calculate the solvent concentration at any position and at any time inside the coating film during the drying process. Moreover, it can also predict the curing time and residual solvent concentration of the coating fabric required to reach drying equilibrium. Compared with coated 3/1 twill, 5/3 satin and 2/1 twill, the solvent diffusion of coated plain fabric was faster during curing. Under the same environmental conditions, the thinner the fabric was and the greater the porosity was, the shorter the curing time was. The fitting equations for fabric thickness, fabric porosity and drying time were obtained, which can provide a theoretical guidance for the preparation, performance research and drying conditions optimization of PMMA coated textile materials.

scholarly journals Comparison of Phenols Content and Antioxidant Activity of Fruits from Different Maturity Stages of Ribes stenocarpum Maxim

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3148 ◽  
Author(s):  
Yuwei Wang ◽  
Delin Qi ◽  
Shulin Wang ◽  
Xiaohai Cao ◽  
Ying Ye ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Design Method ◽  
Extraction Process ◽  
Coumaric Acid ◽  
Solvent Concentration ◽  
Box Behnken Design ◽  
Maturity Stages ◽  
Ripening Stages ◽  
Intracellular Ros ◽  
Unripe Fruits

Differences in the content of nine phenols and the antioxidant capacity of Ribes stenocarpum Maxim (RSM) fruits at different stages of maturity were investigated, and the extraction process of polyphenols from RSM was also optimized using Box-Behnken design method. Results showed that the content of the nine phenols varied considerably at different ripening stages; catechin, chlorogenic acid, coumaric acid, and ferulic acid were abundant in immature fruits but decreased with fruit ripening, whereas the levels of rosemary acid and querctin acid were low in immature fruits and increased with time, reaching the highest value after the fruit was completely mature. The phenols extracted from RSM fruits possessed good antioxidant activities for effective and rapid scavenging of DPPH and ABTS free radicals, as well as intracellular ROS. Analysis of the phenols content at different maturity stages indicated that the unripe fruits had significantly higher polyphenols content than mature fruits. Consequently, unripe fruits possessed higher antioxidant activities. According to the overall results of the extraction process optimization, the selected optimal conditions for extracting polyphenols from RSM were as follows: extraction time, 95 min; solvent concentration, 60%; ratio of sample to solvent, 1:25.

scholarly journals Effect of solvent concentration on performance of polysulfone membrane for filtration and separation

2017 ◽  
Vol 226 ◽  
pp. 012171
Author(s):  
Muhamad Syafiq Mohamad Sofian ◽  
Muhamad Zaini Yunos ◽  
Azlinnorazia Ahmad ◽  
Zawati Harun ◽  
Siti Hajar Mohd Akhair ◽  
...  
Keyword(s):  
Solvent Concentration ◽  
Polysulfone Membrane ◽  
Effect Of Solvent

Effects of organic solvents on immobilized enzyme catalyses. Chymotrypsin immobilized on porous glass

1981 ◽  
Vol 59 (19) ◽  
pp. 2921-2925 ◽  
Author(s):  
J. Bryan Jones ◽  
Diana H. Pliura
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Porous Glass ◽  
Immobilized Enzyme ◽  
Butyl Alcohol ◽  
Solvent Concentration ◽  
Marked Contrast ◽  
Practical Applications ◽  
Tert Butyl Alcohol ◽  
Esterolytic Activity

The esterolytic activity of native chymotrypsin (CT) immobilized on ionically neutral porous glass beads has been studied in the presence of up to 20% (v/v) of the organic solvents methanol, ethanol, 2-propanol, tert-butyl alcohol, dioxane, and DMSO. In marked contrast to the variations observed with native CT, inhibition of CT immobilized on glass (CT–glass) was independent of the nature of the organic solvent. The overall activity, as indicated by kc(app)/km(app), decreased by 35–50% as the concentration of all solvents surveyed was increased up to 20%. In general, high organic solvent concentration accelerated the rate of protein release from the insoluble catalyst. For practical applications in aqueous organic solvents CT–glass conjugates are inferior to those of the enzyme attached to Sephadex.

Study on the Extraction and Purification of Microcystins (MC-LR)

2011 ◽  
Vol 340 ◽  
pp. 318-323
Author(s):  
Wen Yi Zhang ◽  
Ning Han ◽  
Li Rong Yao ◽  
Xiao Lan Qiu ◽  
Xiao Liang Chen
Keyword(s):  
Extraction Method ◽  
Taihu Lake ◽  
High Efficiency ◽  
Extraction Efficiency ◽  
Low Cost ◽  
Solvent Concentration ◽  
Purification Method ◽  
Blue Green Algae ◽  
Extraction Solvent ◽  
Extraction And Purification

The MC-LR from the the blue-green algae of Taihu Lake was extracted, at the same time, a set of microcystins extraction method with methanol as extraction solvent and purification method with C18-SPE as purification workstations were established. The extraction solvent concentration, extraction time, extraction solvent amount, leacheate concentration and eluent concentration were used to research the extraction efficiency of MC-LR. Finally, 80% methanol was used to wash microcytins to make MC-LR high purity and the purity was over 85%. This research presented a method of low cost and high efficiency. It provided the foundation for the further research of microcytins.

scholarly journals Extraction of Phytosterol Concentration in Different Legume Pods by Using Microwave-Assisted Hydrodistillation

2019 ◽  
Vol 19 (3) ◽  
pp. 796
Author(s):  
Noormazlinah Noormazlinah ◽  
Norlaili Hashim ◽  
Abdurahman Hamid Nour ◽  
Mimi Sakinah Abdul Munaim ◽  
Maria Pilar Almajano ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Microwave Power ◽  
Ethanol Concentration ◽  
Irradiation Time ◽  
Optimal Conditions ◽  
Solvent Concentration ◽  
Visible Spectroscopy ◽  
Optimum System ◽  
Microwave Assisted ◽  
Extraction Parameters

The traditional ways in the extraction of bioactive compounds using conventional methods are disadvantageous from both economic and environmental perspectives. In this, the potential of microwave-assisted hydrodistillation conditions for extraction of phytosterol from legume pods was investigated. Salkowski test performed on the legume pod has shown the reddish brown in all sample which confirmed the presence of phytosterol qualitatively. Liebermann-Burchard procedure and ultraviolet-visible spectroscopy (UV-Vis) apparatus were used to study the concentration of phytosterol at different extraction parameters which are temperature (25–80 °C), solvent concentration (50–100% v/v), irradiation time (1–10 min) and microwave power (400–800 W). The optimal conditions for highest yield of extract (0.219 mg/L) were obtained at a microwave power of 600 W, the irradiation time of 6 min, and ethanol concentration of 75% v/v. Results obtained in this study have shown the capability of microwave-assisted hydrodistillation in the extraction of phytosterol from legume pod. Further works are nevertheless required to provide a deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industry.

scholarly journals Optimization of the extraction of natural phenolic antioxidants from the seeds of Tamarindus indica L. - an undervalued by product of food processing - using response surface methodology

2018 ◽  
Vol 62 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Atreyi Sarkar ◽  
Uma Ghosh
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Extraction Time ◽  
Phenolic Antioxidants ◽  
Extraction Temperature ◽  
Tamarindus Indica ◽  
Solvent Concentration ◽  
Antioxidant Power ◽  
Wide Range ◽  
Ferric Reducing Antioxidant Power

The seeds of Tamarindus indica are known to possess a wide range of phenolic compounds with high antioxidant activity as measured by the ferric reducing antioxidant power (FRAP). In the present study, the optimum conditions for the extraction of crude phenolic antioxidants from Tamarind seed were determined using response surface methodology (RSM). A central composite design (CCD) was used to investigate the effects of four independent variables, namely concentration of extractable solids in solvent (g/ml; X1), extraction time (h; X2), extraction temperature (°C; X3) and solvent concentration (%, v/v; X4) on the responses of total polyphenol content (TPC) and FRAP. The CCD consisted of 30 experimental runs. A second-order polynomial model was used for predicting the responses. Canonical analysis of the surface responses revealed that the predicted optimal conditions for the maximal yield of TPC and FRAP were concentration of extractable solids in solvent of 0.049 g/ml, extraction time of 3.24 h, extraction temperature of 45 °C and a solvent concentration of 50%. The experimental values in the optimised condition coincided with the predicted ones within a 95% confidence interval, hence indicating the suitability of the model and the success of RSM in optimizing the extraction parameters.

scholarly journals Solvent Concentration Effect on Powder X-Ray Diffraction and Dissolution Profiles of Acyclovir-Nicotinamide Cocrystals

2017 ◽  
Vol 7 (04) ◽  
Author(s):  
Setyawan D. ◽  
Siswandono Siswandono ◽  
Winantari A. N. ◽  
Zu’aimah K.
Keyword(s):  
Physical Properties ◽  
Oral Bioavailability ◽  
Ethanol Concentration ◽  
Antiviral Agent ◽  
X Ray Diffraction ◽  
Solvent Concentration ◽  
Solubility In Water ◽  
X Ray ◽  
Dissolution Properties ◽  
Slurry Method

Objective : Acyclovir (ACV) is well-known antiviral agent that has absorption problem, mainly due to its poor solubility in water and oral bioavailability. To improve acyclovir physical properties, especially dissolution properties, acyclovirnicotinamide(NCT) cocrystal was formed. Methods : ACV-NCT cocrystal was prepared using slurry method using ethanol as solvent with different concentration. The ACV-NCT cocrystal from each sample groups was characterized using powder X-ray diffraction (PXRD), and then dissolution properties evaluated. Results : Each ACV-NCT cocrystals prepared from slurry method with different ethanol concentrations have different PXRD profile. Dissolution analysis (ED15) showed that ACV-NCT cocrystallization using slurry methods with 10,0 ml/g as ethanol concentration significantly increase ED15 values compared to acyclovir and acyclovir-nicotinamide physical mixture (α=0,05). Conclusion : ACV-NCT cocrystal successfully formed using slurry method with 10,0 ml/g as optimal ethanol concentration.

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