• Elastomers and Composites
• /
• v.54 no.3
• /
• pp.188-200
• /
• 2019

Rubber articles contain various organic additives such as antidegradants, curing agents, and processing aids. It is important to extract and analyze these organic additives. In this paper, various extraction methods of organic additives present in rubber composites were introduced (solvent extraction, Soxhlet extraction, headspace extraction, and solid-phase microextraction), and the extracts were characterized using gas chromatography/mass spectrometry (GC/MS). Solvent and Soxhlet extractions are easy-to-perform and commonly used methods. Efficiency of solvent extraction varies according to the type of solvent used and the extraction conditions. Soxhlet extraction requires a large volume of solvent. Headspace sampling is suitable for extracting volatile organic compounds, while solid-phase extraction is suitable for extracting specific chemicals. GC/MS is generally used for characterizing the extract of a rubber composite because most components of the extract are volatile and have low molecular weights. Identification methods of chemical structures of the components separated by GC column were also introduced.

• The Korean Journal of Food And Nutrition
• /
• v.12 no.4
• /
• pp.358-363
• /
• 1999

This study was conducted to evaluate the extraction methods for the determination of antioxidants in soybean oil. Recovery rates of various antioxidants in soybean oil showed similar rates as 80.4~102.1% by solvent/solvent extraction method and 89.9~106.4% by sweep co-distillation method except 46.6~61.2% of PG at corresponding spiked concentractions. The maximun recovery rates of antioxidnts were obtained when extraction time and extraction temperature used in UNITREX were 20min and 21$0^{\circ}C$ respectively. In the recovery rates with the activation of florisil when 2% ofwater was added to florisil the highest recovery rates for TBHQ, BHA, BHT were obtained by sweep co-distillation met-hod. Therefore sweep co-distillation method showed less solvent simple operation and high recovery rate compared with solvent/solvent extraction method.

• Resources Recycling
• /
• v.26 no.5
• /
• pp.3-11
• /
• 2017

Solvent extraction is an important process to recover pure gold and silver from various leaching solutions. The present work reviews the aqueous chemistry and solvent extraction separation of gold (I, III) and silver (I) from several leaching systems such as cyanide, thiocyanate, thiosulfate, thiourea and chloride medium. The extraction and separation behavior of gold (I, III) and silver (I) by various single and mixtures was compared on the basis of extraction reaction and the selectivity from these mediums. The chloride medium is recommended for the separation of gold and silver by solvent extraction in terms of extraction and stripping efficiency.

• KSBB Journal
• /
• v.26 no.5
• /
• pp.453-458
• /
• 2011

In this study, two different extraction techniques, organic solvent extraction and supercritical carbon dioxide ($SCCO_2$) extraction, were employed to evaluate the extraction efficiency of oil from Chlorella vulgaris. In the organic solvent extraction, the effects of various organic solvent on the extraction yield were investigated. The $SCCO_2$ extraction was carried out while varying such operating parameters as temperature, pressure, $SCCO_2$ flow rate, and cosolvent. About 4.9 wt% of oil was extracted from ground Chrollera vulgaris for 18 h when dichloromethane/methanol (2：1, v/v) was used as an extraction solvent. The oil yield of the $SCCO_2$ extraction was found to be very low (0.53 wt%) and to increase up to about 0.86 wt% with the addition of cosolvent.

• Natural Product Sciences
• /
• v.25 no.2
• /
• pp.150-156
• /
• 2019

Conventional extraction of oil and azadirachtin, a botanical insecticide, from Azadirachta indica involves defatting the seeds and leaves using hexane followed by azadirachtin extraction with a polar solvent. In order to simplify the process while maintaining the yield we explored a binary extraction approach using Soxhlet extraction device and hexane and ethanol as non-polar and polar solvents at various ratios and extraction times. The highest oil and azadirachtin yields were obtained at 6 h extraction time using a 50:50 solvent mixture for both neem leaves (44.7 wt%, $720mg_{Aza}/kg_{leaves}$) and seeds (53.5 wt%, $1045mg_{Aza}/kg_{leaves}$), respectively.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.6
• /
• pp.66-71
• /
• 2011

Various single solvents were tested to find the effective solvent for the extraction of algae oil from wet-form Chlorella minutissima. In the case of single solvents, their extractabilities for algae oil were increased with their polarity because the water in wet algae cell is to form a solvent shell around the lipids. Based on these results, the wet-form algae samples were treated with a polar alcohol solvent and then a nonpolar solvent was added in algae residue. In the algae oil extraction by ethanol/n-hexane, total lipid contents were 40-50% and composition of triglyceride in extracted oil was 46.50%. Considering solvent toxicity of conventional solvent mixture such as chloroform and methanol for algae oil extraction, the ethanol/n-hexane system was identified as the effective one for the oil extraction from wet-form Chlorella minutissima.

• Journal of Environmental Science International
• /
• v.7 no.6
• /
• pp.753-759
• /
• 1998

In physical and reactive extraction of acrylic acid using various solvents the equilibrium characteristics of extraction were investigated. The degree of extraction in reactive extraction with Tri-n-octylamine(TOA) was 1.5~3 times than that in physical extraction. Distribution ratio was constant in methyl isobutyl ketone(MIBK) and n-butylacetate(n-BAc) but was increased with increasing the concentration of acrylic acid in benzene and chloroform. It can be explained by formation of dimers. Maximum extraction leadings of acrylic acid were three in benzene and were two in MIBK, chloroform and n-BAc, and it was found that acrylic acid was extracted as the form of $A_3$R In benzene and $A_2R$ in MIBK, chloroform and n-BAc. In effect of solvent, the degree of extraction was increased as he difference of solubility parameter of solvent and solute was decreased, and as dielectric constant of solvent was increased.

• KSBB Journal
• /
• v.19 no.6 s.89
• /
• pp.421-426
• /
• 2004

The extraction and separation of isoflavones from Korean soybean were peformed by various mechanical and chemical extraction methods. They included solvent extraction, stirring, supersonification and sub/supercritical water extraction. From the experimental results of the variation of solvent extraction by change in composition, the increase in extraction of a specific compound by stirring or supersonic energy, and the application of supercritical fluid with superior solvating power over solvents, the sonification was the most desirable extraction method in extracting aglycone isoflavones, daidzein and genistein from Korean soybean.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.3
• /
• pp.406-412
• /
• 1998

Such extraction conditions as the kinds of solvent, extracting temperature, extracting time, ratio of material to solvent and particle size of material, were studied to maximize the extraction of oleoresin from chipi. Larger amount of soluble solids were extracted from seeds with nonpolar solvents (hexane, pentane, ether) for extraction, because the seeds contained large amount of crude fats and monoterpene(limonene) volatile compounds. Larger amount of soluble solids were extracted from peel with polar solvents(methanol, ethanol) of extraction because of large amount of water soluble colors, sugars and oxygenated terpene bolatile compounds in the peel. The application of the solvents in intermediate polarity (dichloromethane, acetone) resulted in more effective extraction of soluble solid and volatile compounds. Expecially, dichloromethane was an excellent solvent in extraction of volatile compounds. In the concern of volatile compound recovery yield, the optimum extraction conditions, such as temperature, time, mixing ratio of material to dichloromethane and mean particle size, were $25^{\circ}C$, 10min, 1:10(w/v), 355~250${\mu}{\textrm}{m}$ for chopi peels and 3$0^{\circ}C$, 10min, 1:8(w/v), 355~250${\mu}{\textrm}{m}$ for chopi seeds, respectively.

• Journal of Industrial Technology
• /
• v.27 no.B
• /
• pp.161-167
• /
• 2007

The objetives of this study are to set up optimum extraction temperature, time and organic solvent for propolis extraction, to investigate chemical properties, and to develop health foods from propolis preparation. In this study, ethanol and ultrasonic extracts method performed to optimum extraction temperature was at 60, $20^{\circ}C$, optimum extraction time was at 12, 4 hours and optimum extraction amount of solvent was at 20, 15 times of propolis weight. When various ethanol solutions were used, whereas flavonoid content was highest in 70, 80% aqueous ethanol, respectively. So the ultrasonic extracts method used gave better results than the ethanol extracts method in this work. Extraction of propolis with etanol and ultrasonic extracts method was performed by using the water and various concentrations of aqueous ethanol as solvent. Sensitivity of propolis samples to Staphylococcus aureus was investigated and the results were shown. Samples of water extract did not inhibit microbial growth, where as 50% aqueous ethanol extract the largest inhibitory zone for Staphylococcus aureus, then decreased inhibition with increasing ethanol concentrations.