Increasing Extraction Temperature Research Articles

Extraction of caffeine, chlorogenic acids and lipids from green coffee beans using supercritical carbon dioxide and co-solvents

The paper reports on experimental data on the extraction of caffeine, coffee oil and chlorogenic acids from green coffee beans using pure supercritical CO2 and supercritical CO2 modified with ethanol (5% w/w) and isopropyl alcohol (5% w/w) at 50 and 60ºC and 15.2 24.8 e 35.2 MPa. In this study extraction kinetics were obtained for all assays i.e. samples were collected at several time intervals for each solvent and mixed solvent. When pure CO2 and CO2-ethanol mixed solvent were used, an increase in pressure resulted in an increase in the amount of oil extracted. When CO2 was modified with isopropyl alcohol, the amount of coffee oil extracted also increased with pressure. Caffeine extraction initially increased and subsequently decreased with pressure. Chlorogenic acids were only extracted when isopropyl alcohol was used as a co-solvent. An increase in extraction temperature resulted in a decrease of caffeine and oil extraction (retrograde condensation) when only CO2 was used as solvent. With the use of co-solvent this retrograde behavior was no longer observed and the increase in temperature resulted in the increase in the extracted amounts of caffeine, coffee oil and chlorogenic acids.

Production of low ash coal by thermal extraction with N-methyl-2-pyrrolidinone

Present study was conducted for the purpose of producing low ash coal from LRC (low rank coals) such as lignite and sub-bituminous coal through thermal extraction using polar solvent. Extraction from bituminous coal was also investigated for comparison. NMP as a polar solvent was used. The ratio of coal to solvent was adjusted as 1: 10. Experimental conditions were established which include the extraction temperature of 200–430 °C, initial applied pressure of 1–20 bar and extraction time of 0.5–2 hr were used. Extraction yield and ash content of extracted and residual coal were measured. The extraction yield increased with the increase of extraction temperature, and the ash content of extracted coal decreased below 0.4% at 400 °C from the raw coal samples that have the ash contents of 4–6%. According to the analysis of experiments results, fixed carbon and calorific value increased, and H/C and O/C decreased.

Pressurized Liquid Extraction of Flavonoids from Spinach

Pressurized liquid extraction (PLE) using water and a 70:30 mixture of ethanol and water over the temperature range of 50 to 190 degrees C was used to extract flavonoids from dried spinach. The total phenolic content, antioxidant capacity, color, and browning indices of the extracts were also evaluated. PLE using a 70:30 mixture of ethanol and water was more effective than water in extracting flavonoids from spinach. Flavonoids were effectively extracted over the temperature band of 50 to 130 degrees C with water and 50 to 150 degrees C with ethanolic solvent. Levels of total phenolics and ORAC values increased with increasing extraction temperature, indicating that flavonoids were minor contributors to antioxidant capacity at elevated extraction temperatures. Browning of ethanolic extracts correlated highly with ORAC values over the temperature range of 50 to 190 degrees C, and the ORAC values of the large molecular weight fraction (> 1000 Da) increased linearly over the temperature range, indicating that Maillard polymers were the major contributors to antioxidant capacity. The results illustrate that PLE temperatures of < 130 degrees C for water or < 150 degrees C for ethanolic solvent may be used to extract flavonoids, followed by a high temperature (> 170 degrees C) extraction to generate antioxidant-rich moieties.

The Effect of Solvent Extraction of Light Lubricating Oil on Viscosity Index and Chemical Composition

An investigation was conducted for the improvement of viscosity index of light lubricating oil fraction (40 stock)obtained from vacuum distillation unit of lube oil plant of Daura Refinery, using solvent extraction process.In this study furfural solvent was used to extract the undesirable materials which reduce the viscosity index of rawlubricating oil fraction.The studied effecting variables of extraction were extraction temperature range from 70 to 110°C, and solvent to oilratio range from 1:1 to 4:1 (wt/wt).The n-d-M method was used for calculation of carbon distribution and structural group analysis of the raffinateproduced from furfural extraction.Also the three component phase diagram for a mixed-base oil and furfural at different temperature was drawn.The results of this investigation show that the viscosity index of lubricating oil fraction increases with increasingextraction temperature and increasing the solvent to oil ratio and reaches 115.6 at extraction temperature 110°C andsolvent to oil ratio 4:1.Further more, the results show that the viscosity, refractive index, density, sulfur content and percentage yield ofproduced raffinate were decreased as the extraction temperature or solvent to oil ratio increases for extraction process.

Effects of extraction parameters on gel properties of carrageenan from Kappaphycus alvarezii (Rhodophyta)

Carrageenan was isolated under different extraction conditions from Kappaphycus alvarezii collected in North Sulawesi, Indonesia. Its gel properties include very strong elasticity even at low concentrations. Molecular weight and rheological properties were obtained by gel permeation chromatography and dynamic viscoelasticity measurements in order to clarify the average molecular weight at various extraction temperatures (50, 70, 90°C) and times (1, 3, 5 h), as well as gel formation ability. The results showed that both the weight-average and the number-average molecular weight decreased with increasing extraction temperature. However, the gelation rate of the carrageenan was found to be constant at around 40°C, whereas the storage modulus, G′, and loss modulus, G″, of the gels differed from each other.

Extraction of green coffee oil using supercritical carbon dioxide

Supercritical CO 2 extraction was used to refine coffee oil obtained by mechanical pressing. Extractions were carried out using 50–70 °C and pressures ranging from 15.2 to 35.2 MPa, with a CO 2 flow rate of 1 standard L/min using a semi-continuous high-pressure extraction apparatus. Green coffee oil fractions were collected at fixed time intervals and the composition of each fraction was determined by HPLC analyses. Caffeine and traces of chlorogenic acid were detected in the first fractions while waxes remained in the extraction vessel. Compared with the original oil the triglyceride composition remained almost unchanged in the fractions. The results also indicate an increase of triglyceride and caffeine extraction with pressure. An increase in extraction temperature results in a retrograde behavior over the pressure range of 15.2–28.3 MPa. At pressures higher than 30 MPa the solubility behavior of coffee oil was apparently independent of the temperature. A good correlation of the solubility data of green coffee oil was obtained using the Chrastil equation.

Influence of experimental conditions on the extraction of phenolic compounds from parsley ( Petroselinum crispum) flakes using a pressurized liquid extractor

The influence of six pressurized liquid extraction parameters (temperature, pressure, particle size, flush volume, static time, and solid-to-solvent ratio) on the extraction of phenolic compounds from parsley flakes was examined. Parsley extracts were analyzed for their phenolic content by high performance liquid chromatography and Folin–Ciocalteu assay. The two major phenolic compounds extracted from parsley flakes were identified as apiin and malonyl-apiin. Particle size, solid-to-solvent ratio, and temperature influenced the amount of phenolic compounds extracted from parsley flakes. Higher extraction yields of phenolic compounds were obtained when extractions were performed with the smallest particle size (<0.425 mm) fraction. Temperature also showed a significant impact on the phenolic profile of the parsley extracts. The yield of malonyl-apiin decreased, while the amount of acetyl-apiin improved with the increase in extraction temperature. The latter compound (acetyl-apiin) is formed by decarboxylation of malonyl-apiin. The yield of the phenolic compounds did not increase proportionately with the increase in sample size, thereby suggesting that it is essential to have optimum solid-to-solvent ratio for accurate estimation of bioactive phytochemicals in foods. Flush volume did not show any major influence on phenolic yields, but it can be manipulated to reduce usage of extraction solvents, which in turn decreases solvent waste disposal costs generated after extraction. Similarly, changes in the static time (extraction time per cycle) and pressure did not result in any significant change in the yield of phenolic compounds extracted from parsley samples. However, sample throughput can be increased significantly by reducing static time.

Extraction of Hydrocarbons from Crude Oil Tank Bottom Sludges using Supercritical Ethane

A custom‐built, solvent recirculating, supercritical fluid extraction (SFE) apparatus was used to study the extraction of hydrocarbons from a crude oil tank bottom sludge (COTBS) with supercritical ethane. The SFE experiments were carried out varying the pressure (10 MPa and 17.20 MPa) and temperature (35°C and 65°C). The yield of the extracted hydrocarbon fraction increased with increase in extraction pressure at constant temperature, and decreased with increase in extraction temperature at constant pressure. The maximum extraction yield was obtained at the pressure and temperature conditions that lead to the highest solvent density. The extracted hydrocarbon fraction was a significantly upgraded liquid relative to the original untreated COTBS.

Tea extraction methods in relation to control of epimerization of tea catechins

AbstractEffect of water temperature and ethanol concentration on epimerization and extractability of tea catechins was investigated. The results showed that epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) were partially epimerized into gallocatechin gallate (GCG) and catechin gallate (CG), respectively, when tea catechins extract was heated in water solution at 100 °C for 2 h or dry tea was extracted in water at 100 °C. The epimerization of the catechins was inhibited if the tea catechins extract was heated as solid powder and the dry tea was extracted in 50% (v/v) ethanol or in water at 80 °C or below. When the dry tea was extracted in water, the extractability of catechins increased with the increase of extraction temperature up to 100 °C, but there was no statistically significant difference in total catechins between 80 °C and 100 °C. When teas were extracted using ethanol solutions, the highest extractability of total catechins was obtained in 50% (v/v) ethanol for dry tea and in 75% (v/v) ethanol for fresh tea leaf. In order to reveal the real profiles of tea catechins in teas to be tested, dry tea should be extracted in 50% (v/v) ethanol for 10 min, while fresh tea leaf should be extracted in 75% (v/v) ethanol for 10 min. For commercial extraction, temperature should be controlled at 80 °C if water is used as the solvent. Copyright © 2007 Society of Chemical Industry

Characterisation of HyperCoals from coals of various ranks

Ashless coals (HyperCoal) produced by thermal extraction of coals of different ranks with 1-methylnaphthalene at temperatures from 300 to 420 °C for 60 min were characterised. HyperCoal has many light components that are easily volatised and decomposed, and it has high thermal reactivity. All the HyperCoals showed high thermoplasticity during heating; in particular, HyperCoals obtained from low-rank Pasir and Mulia coals showed high thermoplasticity beginning at temperatures near 150 °C. On increasing the extraction temperature for Pasir sub-bituminous coal, the weight loss during heating decreased and the resolidification temperature shifted to higher temperatures. These results suggest that the Pasir-HyperCoal obtained at higher temperatures contains more, relatively heavy components. Nuclear magnetic resonance measurements showed that the ratio of aromatic carbon increased with increasing extraction temperature, indicating that some modification reactions occurred.

Recovery of nitrotoluenes in wastewater by solvent extraction

Toluene extraction was utilized to recover 2,4-dinitrotoluene (DNT), 2,6-DNT, and 2,4,6-trinitrotoluene (TNT) from wastewater of toluene nitration process. The batch-wise experiments were performed to elucidate the influence of various operating variables on the extracting behavior, including extracting temperature, volume ratios of solvent versus wastewater, agitation time, acidity of wastewater, and extraction stages. It was found that recovery of total organic compounds (TOC) was significantly elevated with increasing extraction temperature. Besides, high volume ratio of toluene/wastewater (2.0) and wastewater acidified to lower pH value enhanced the recovery percentage of TOC, in which extractable tendency was as follows: 2,6-DNT > 2,4-DNT > 2,4,6-TNT. It is worth noting that the nitrotoluenes in wastewater would be almost completely recovered using three sequential stages toluene extraction at the agitation time of 12 min and pH 3.0. It is apparent that this established method is promising for the treatment of wastewater from toluene nitration processed industrially.

볶음 처리 새송이버섯의 추출조건에 따른 생리기능적 특성 변화

볶음 처리한 새송이버섯의 환류추출조건에 따른 추출물의 생리기능적 특성을 살펴보았다. 에탄올농도에 따라서는 50% 에탄올농도로 추출하였을 때 총 페놀성 화합물 함량 및 수소공여능이 높은 것으로 나타났으며, 75% 에탄올농도로 추출하였을 때 SOD 유사활성이 높은 것으로 나타났다. 아질산염 소거능의 경우에는 에탄올농도가 낮을수록 높은 것으로 나타났다. 추출시간이 증가할수록 수소공여능은 감소하는 것으로 나타났으며, SOD 유사활성 및 아질산염 소거능은 증가하는 것으로 나타났다. 추출온도가 증가할수록 수소공여능 및 SOD 유사활성은 감소하는 것으로 나타났으며, 아질산염 소거능은 큰 차이를 보이지 않았다. 용매에 대한 시료량이 증가할수록 수소공여능, SOD 유사활성 및 아질산염 소거능이 감소하는 것으로 나타났다. 이상의 결과를 바탕으로 하여 볶음 처리한 새송이버섯의 추출조건 설정에 활용 될 수 있으리라 사료된다.

Analysis of Recovered Solvents from Coal Liquefaction in a Flowing-Solvent Reactor by SEC and UV-Fluorescence

Point of Ayr coal has been extracted using three solvents: tetralin, quinoline and 1-methyl-2-pyrrolidinone (NMP); at two temperatures: 350°C and 450°C, corresponding approximately to before and after the onset of massive covalent bond scission by pyrolysis. These solvents differ in solvent power and the ability to donate hydrogen atoms to stabilize free radicals produced by pyrolysis of the coal. Analysis of the fresh solvents and recovered solvents from coal liquefaction was achieved by size exclusion chromatography and UV-fluorescence spectroscopy. In the blank run, it was testified that the filling material sand and the steel powder did not react with solvent with increasing reaction temperature. The role of hydrogen donation in the tetralin extracts was to increase the proportion of large molecules with increasing extraction temperature. Quinoline and NMP both have the powerful extracting capability to get more materials out of coal with increasing extraction temperature.

Solar Extraction of Tar from Tar Sand Using Hot Kerosene

Utilization of solar energy for the heating of kerosene to be used in the extraction of tar from tar sand was theoretically and experimentally investigated. The idea is to replace the working fluid of a conventional flat-plate collector with kerosene instead of water. Hot kerosene is stored in a tank at a temperature of 50–75°C after, which it flows through an extractor filled with tar sand. Thermal performance of collector was found and compared with that of a similar collector with water as a working fluid. Preliminary extractor performance was also found in terms of percentage of recovery versus kerosene temperature. It was found that the efficiency of the collector using water was reduced by 15% when the working fluid was replaced with kerosene, and this was in fair agreement with the theoretical prediction. It was also found that, for the tar sand sample used, the percentage of recovery approaches 30% as the extraction temperature was increased to 70°C. Further increase in extraction temperature had a negligible effect on recovery.

Analysis of solvent extracts from coal liquefaction in a flowing solvent reactor

Point of Ayr coal has been extracted using three solvents, tetralin, quinoline and 1-methyl-2-pyrrolidinone (NMP) at two temperatures 350 and 450 °C, corresponding approximately to before and after the onset of massive covalent bond scission by pyrolysis. The three solvents differ in solvent power and the ability to donate hydrogen atoms to stabilise free radicals produced by pyrolysis of the coal. The extracts were prepared in a flowing solvent reactor to minimise secondary thermal degradation of the primary extracts. Analysis of the pentane-insoluble fractions of the extracts was achieved by size exclusion chromatography, UV-fluorescence spectroscopy in NMP solvent and probe mass. With increasing extraction temperature, the ratio of the amount having big molecular weight to that having small molecular weight in tetralin extracts was increased; the tetralin extract yield increased from 12.8% to 75.9%; in quinoline, increasing extraction temperature didn't have an effect on the molecular weight of products but there was a big increase in extract yield. The extracts in NMP showed the enhanced solvent extraction power at both temperatures, with a shift in the ratio of larger molecules to smaller molecules with increasing extraction temperature and with the highest conversion of Point of Ayr coal among these three solvents at both temperatures. Solvent adducts were detected in the tetralin and quinoline extracts by probe mass spectrometry; solvent products were formed from NMP at both temperatures.

Analysis of solvent extracts from coal liquefaction in a flowing solvent reactor

Point of Ayr coal has been extracted using three solvents, tetralin, quinoline and 1-methyl-2-pyrrolidinone (NMP) at two temperatures 350 and 450 °C, corresponding approximately to before and after the onset of massive covalent bond scission by pyrolysis. The three solvents differ in solvent power and the ability to donate hydrogen atoms to stabilise free radicals produced by pyrolysis of the coal. The extracts were prepared in a flowing solvent reactor to minimise secondary thermal degradation of the primary extracts. Analysis of the pentane-insoluble fractions of the extracts was achieved by size exclusion chromatography, UV-fluorescence spectroscopy in NMP solvent and probe mass. With increasing extraction temperature, the ratio of the amount having big molecular weight to that having small molecular weight in tetralin extracts was increased; the tetralin extract yield increased from 12.8% to 75.9%; in quinoline, increasing extraction temperature didn't have an effect on the molecular weight of products but there was a big increase in extract yield. The extracts in NMP showed the enhanced solvent extraction power at both temperatures, with a shift in the ratio of larger molecules to smaller molecules with increasing extraction temperature and with the highest conversion of Point of Ayr coal among these three solvents at both temperatures. Solvent adducts were detected in the tetralin and quinoline extracts by probe mass spectrometry; solvent products were formed from NMP at both temperatures.

Enrichment of hyperforin from St. John's wort (Hypericum perforatum) by pilot-scale supercritical carbon dioxide extraction.

St. John's Wort (Hypericum perforatum L.) was extracted with supercritical carbon dioxide using a pilot batch extraction plant. The effects of pressure, temperature, flow rate and extraction time were examined with respect to extraction yield and hyperforin content. Supercritical carbon dioxide showed a high selectivity for phloroglucinols. Extracts were analyzed using an isocratic HPLC method with a mixture of hyperforin/adhyperforin as an external standard. Within the studied range of extraction pressure (90-150 bar) and extraction time (1-5 h), extraction at 90 bar for 3 h and 120 bar for 1 h provided higher hyperforin content (up to 35%) in the resulting extracts. An increase in extraction temperature showed a negative effect, leading to increased degradation of hyperforin into orthoforin. When the total mass of carbon dioxide passing the extraction vessel was kept constant, changes in mass flow rate did not affect the extraction result.

Extraction of chili, black pepper, and ginger with near-critical CO2, propane, and dimethyl ether: analysis of the extracts by quantitative nuclear magnetic resonance.

Ginger, black pepper, and chili powder were extracted using near-critical carbon dioxide, propane, and dimethyl ether on a laboratory scale to determine the overall yield and extraction efficiency for selected pungent components. The temperature dependency of extraction yield and efficiency was also determined for black pepper and chili using propane and dimethyl ether. The pungency of the extracts was determined by using an NMR technique developed for this work. The volatiles contents of ginger and black pepper extracts were also determined. Extraction of all spice types was carried out with acetone to compare overall yields. Subcritical dimethyl ether was as effective at extracting the pungent principles from the spices as supercritical carbon dioxide, although a substantial amount of water was also extracted. Subcritical propane was the least effective solvent. All solvents quantitatively extracted the gingerols from ginger. The yields of capsaicins obtained by supercritical CO(2) and dimethyl ether were similar and approximately double that extracted by propane. The yield of piperines obtained by propane extraction of black pepper was low at approximately 10% of that achieved with dimethyl ether and CO(2), but improved with increasing extraction temperature.

Extraction of anthocyanins and other phenolics from black currants with sulfured water.

Health benefits of fruits, vegetables, and red wine are attributed to anthocyanins and other phytochemicals. In this research, the extraction of phenolics from black currants was optimized using different SO(2) concentrations (28, 300, 700, 1100, and 1372 ppm), temperatures (6, 20, 40, 60, and 74 degrees C), and solvent to solid ratios (S/S) (6, 20, 40, 60, and 74 mL/g). Surface response methodology was used to optimize yields of anthocyanins and total phenolics, as well as their antiradical and antioxidant activities. The extraction of phenolics varied with the SO(2) concentration, S/S, and temperature. Maximum yields of total phenolics and anthocyanins were obtained at an SO(2) concentration of 1000-1200 ppm and 19 L of solvent/kg of milled frozen berries. The increase of extraction temperature increased the rate of extraction and, thus, times to reach equilibrium for the extraction of total phenolics and anthocyanins were reduced. However, for the extraction of anthocyanins it is recommended that temperatures of 30-35 degrees C be used, as higher temperatures will degrade these compounds. Antioxidant activity was affected by all three experimental variables evaluated; however, the main variable affecting it was S/S. The higher the S/S, the lower the antioxidant index.

Catalytic hydrocracking of primary maceral concentrate extracts prepared in a flowing solvent reactor

Differences between the behaviour of coal macerals during liquefaction and catalytic hydrocracking were investigated. The liquefaction experiments were carried out in tetralin, using a flowing solvent reactor. The extracts were catalytically hydrocracked in a micro-bomb reactor, using a commercial catalyst. Extracts and hydrocracked products were characterised by size exclusion chromatography (SEC), UV-fluorescence spectroscopy (UV-F), probe-mass spectrometry and thermogravimetric analysis. Conversions of the vitrinite and the liptinite concentrates during liquefaction were high (∼89%), while inertinite samples yielded a little over 20% extract. For inertinites, the emerging picture was consistent with high cross-link density. Liptinite was extracted less completely at lower temperatures and more slowly at high temperatures compared to corresponding vitrinites and vitrinitic coals. Long chain aliphatics released from the liptinite concentrate between 340 and 390°C appeared likely to have originated in lower-molecular mass material occluded in the sample matrix and dissolving in tetralin prior to the onset of massive covalent bond scission. SEC chromatograms showed material of larger MMs in liptinite and vitrinite extracts than in the inertinite extract. The molecular mass distributions broadened with increasing extraction temperature. Catalytic hydrocracking experiments were carried out in a micro-bomb reactor for 10 and 120 min at 440°C, under 190 bar of hydrogen. In hydrocracking, the liptinite was the slowest extract to react at short reaction times (∼10 min). However, at longer reaction times, its products showed the smallest MM-distribution. Smaller differences were observed between the chromatograms of the 10 and 120 min hydrocracked products of the inertinite extract. Differences between spectra of the three extracts would strongly suggest the presence of larger (and apparently irreducible) polycyclic aromatic ring systems, in the hydrocracked products of the inertinite extract.