• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.3855-3860
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• 2011

The competitive solvent extractions of alkali and alkaline earth metals by di-ionizable calix[4]arene nano-baskets were studied using nine conformers of calix[4]arene nano-baskets. The objective of this work is to assess the variation of macrocycle conformation, orientation and position of pendant moieties upon the extraction parameters (efficiency, selectivity and $pH_{1/2}$) of the complexes. The results revealed that alternation of ring conformation in calixarene scaffold affects the solvent extraction parameters towards alkali and alkaline earth metals, while changing the orientation of pendant moieties from ortho- to para- as well as cis- to trans-analogues depicted no changes in those extraction parameters.

• Journal of the Korean Wood Science and Technology
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• 제25권1호
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• pp.23-27
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• 1997

Alkali-soluble extracts were prepared from barks of Japanese larch(Larix leptolepis). Siberian larch(Larix gmelineii) and Radiata pine(Pinus radiata) The effect of various factors, such as particle size, liquor ratio, extraction temperature, and reaction time, on the extracts yield was investigated. Particle sizes affected the alkali-soluble extracts; the finer the particle size, the higher extracts and extract efficiency. High temperature and high liquor ratio were more effective. In the range of 0.25% to 1% NaOH concentration, alkali extracts were increased with the increasing alkali concentration. However, extract yields were leveled off above 0.5% alkali concentration. Extractions with NaHCO3 were almost equivalent to those of NaOH extraction. 1% NaOH and 1% NaHCO3 resulted in the highest yields of alkaline extracts. Extracts from Japanese larch were lower than those from Siberian larch and Radiata pine barks. Siberian larch bark was the best raw material for tannin adhesives, because its extractive yield was higher than those of the other barks. Concerning pH of alkaline media during extraction, small increases of the extract yields were resulted at range of pH 7 to pH 9, while a large increases from pH 9.0 to pH 12. This phenomenon is attributed to higher alkalinity.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1509-1516
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• 2012

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclusion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixarene in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of $p-tert-calix$[4]arene bearing different sulfonamide moieties were synthesized and their inclusion-extraction parameters were optimized including the calixarene scaffold $\mathbf{3}$ (4 wt %) as the carrier/demulsifier, the commercial kerosene as diluent in membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The selectivity of membrane over more than ten interfering cations was examined and the results reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.

• 펄프종이기술
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• 제43권1호
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• pp.83-91
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• 2011

Hemicelluloses are useful materials for papermaking and other biotechnological applications. To recover and further utilize the hemicelluloses, this study carried out the pre-extraction of the hemicelluloses from Korean mixed hardwoods chips using hot water and sodium hydroxide solution at various temperature and time conditions. Through the hot water pre-extraction, the wood components of 22% was extracted and the 35% of the hemicelluloses which were contained in the original wood chips were dissolved into the pre-extractives. The yield of the pre-extractives was more significantly influenced by the pre-extraction temperature than the time. The pre-extractives with the yield of 30% could be obtained by alkali pre-extraction and alkali concentration was the most important factor. It had lower hemicellulose content but high molecular weight, compared with the hot water pre-extractives.

• 한국응용과학기술학회지
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• 제22권3호
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• pp.219-227
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• 2005

Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid $\underline{3}$. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{2}$. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{4}$ showed good selectivity for $Na^+$ over $Mg^{2+}$, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of $Na^+$ as the second extracted ion was much better crown ether carboxylic acid $\underline{1}$ than crown ether phosphonic acid $\underline{2}$, while the efficiency of $Na^+$ extraction was better $\underline{2}$ (83% total loading) than $\underline{1}$ (32%).

• 한국응용과학기술학회지
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• 제22권1호
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• pp.50-55
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• 2005

A comparison of alkali metal cation and alkaline earth cation solvent extraction was made for three additional monoionizable crown ethers and one diionizable crown ether. sym-(n-Octyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ exhibited high efficiency and selecvity in solvent extraction of alkali metal cations with respect to that observed with alkaline earth cations. Sizes of $Na^+$ and $Ca^{2+}$ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{3}$. As the result, $Na^+$ and $Ca^{2+}$ are the best extracted. sym-(n-Octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid $\underline{4}$was found to be somewhat selective for $Na^+$ over $Li^+$ and other alkaline earth metal cations. In the complexation of alklaine earth cations by crown ether diphosphonic acid $\underline{4}$, $Ca^{2+}$ and $Sr^{2+}$ are the appropriate sizes, but lager $Ba^{2+}$ may be due to favorable formation of a sandwich type complex between the crown ether cavity and the dianion of the deprotonated crown ether phoaphonic acid moiety.

• 펄프종이기술
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• 제29권2호
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• pp.36-45
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• 1997

Newly bleaching sequence using oxygen, ozone and hydrogen peroxide has introduced to avoid pollution hazards from chlorinated organic compounds, because chlorine dioxide substitution bleaching was produced a little chlorinated organic substance. Oxygen-type chemicals replaced for chlorine has attracted much research attention. Bleachability of ozone was improved at low temperature and high pulp consistency. In third bleaching followed OZ bleaching, addition of O2 and NaBH4 in alkali extraction was effective than only alkali extraction. Bleachability of pulps in ozone bleaching(Z) was improved at higher consistency and lower temperature The addition O2 and NaBH4 in alkali extraction after OZ bleaching sequence improved brightness, when compared to those obtained by only alkaline extraction. Pulps bleached by ECF bleaching sequences such as OZEoD and OZEopD was obtained by 90% ISO brightness. The brightness of pulp bleached by TCF sequences with the ozone dosage of 1.6% was approached to target brightness (88~90%ISO). Pulps bleached Z stage combined bleaching sequence was reduced the viscosity to a little greater extent. However, physical properties of pulps was not great different compared to those bleached by conventional bleaching sequences. A pollution index of bleaching effluente by ozone combined bleaching sequences was lower than by conventional bleaching sequence, but somewhat higher than multistage bleaching sequences combined C/D stage.

• 대한화학회지
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• 제30권4호
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• pp.359-368
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• 1986

Crown ether (DC18C6, DC24C8)과 HDEHP로 알칼리 금속 이온을 용매 추출할 때의 추출평형을 연구하였다. 추출평형상수는 DC18C6계에서 $Na^+순으로 증가하였으며 DC24C8계에서는 $Rb^+순으로 증가하였다. 유기용매상으로 추출되는 추출종은 $M_1(crown ether)_1\;(HDEHP)_1$이며 추출평형상수의 크기는 crown ether의 유기용매상과 수용액상에서의 분배비와 crown ether-알칼리금속 착물의 안정도 상수에 의해서 결정된다.

• 한국식품영양과학회지
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• 제33권4호
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• pp.747-752
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• 2004

HWEM(hot-watele material ), WSA(water soluble alginate), ASA(alkali soluble alginate), AASA(acid alkali soluble alginate)의 네 가지 알긴산 추출방법을 이용해서 다시마(Laminaria religiosa), 미역(Undaria pinnatifida), 톳(Hizikia fusiforme)의 3가지 시료를 가지고 알긴산을 추출하여 수율을 알아본 결과 사용된 시료 중에서 AASA추출방법에 의한 미역에서의 알긴산 함량이 39.6%로 가장 우수하게 나타났으며 HWEM은 10.2∼18.6% 정도의 수율로 AASA 방법으로 얻은 수율보다 절반밖에 미치지 못하였다. 제조된 알긴산 분말의 색도는 다시마로부터 WSA추출법을 이용해서 제조한 알긴산의 ΔE값이 20.63으로 가장 밝게 나왔으며 추출에 사용된 모든 시료들에 있어서 WSA추출방법에 의한것이 밝은 색도를 가지며 ASA 추출방법을 이용해서 얻은 알긴산의 색도는 ΔE값이 75.31로 다른 것에 비해 어두운 색의 알긴산이 제조되었다. AASA 추출방법에서 3% $Na_2$CO$_3$ 농도에서 37.1%로 높은 수율을 얻을 수 있었으며, H$_2$SO$_4$의 농도를 0.1, 0.2, 0.4 N로 변화시켜서 추출한 결과는 0.4 NH$_2$SO$_4$에서 34.9%의 높은 수율을 나타냈다. 톳에서 추출한 알긴산의 점도는 상업용에 비해 훨씬 낮은 점도를 나타내었으며 ASA추출 방법에 의해 얻어진 알긴산의 점도가 WSA에 의한 것보다 높은 점성을 나타내었다.

• 펄프종이기술
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• 제42권2호
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• pp.88-94
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• 2010

Cattail (Typha L.) was used as a raw material for producing both bio-ethanol and pulp for papermaking at the same time. Pretreatments of cattail stems and leaves with acid ($H_2SO_4$) and alkali (NaOH) in three different addition levels were studied before soda pulping. The acid pretreatment gave reducing sugar of 15.2% of initial weight, but alkali pretreatment close to 1%. Soda pulping of the pretreated cattail gave 3% reduction in pulp yield and less bonding properties in paper; however, refining of the pulp from the pretreated cattail with alkali restored their fiber bondings up to that of the pulp from no-pretreated cattail at equivalent freeness.