• 분석과학
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• 제6권1호
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• pp.21-27
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• 1993

54% 순도의 공업용 n-헥산을 HPLC급으로 분리, 정제하였다. 분별증류법으로 분리하기 어려운 methylcyclopentane, 2-methylpentane, 그리고 3-methylpentane 등은 molecular aieve 5A를 이용한 액체-고체 크로마토그래피법으로 분리하였다. HPLC 용매로서 엄격히 규제받는 UV와 형광불순물은 알루미나와 실리카겔을 이용한 흡착법으로 정제하였다. 이와 같은 방법으로 n-헥산을 정제함으로써 수분, 색도(APHA), 산도, 증발잔류물, 황 및 thiophene 등의 불순물 항목을 모두 HPLC급의 규격까지 낮출 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3829-3834
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• 2013

$H{\beta}$ (core)/SAPO-11 (shell) composite molecular sieve was synthesized by the hydrothermal method in order to combine the advantages of $H{\beta}$ and SAPO-11 for the methylation of naphthalene with methanol. For comparison, the mechanical mixture was prepared through the blending of $H{\beta}$ and SAPO-11. The physicochemical properties of $H{\beta}$, SAPO-11, the composite and the mechanical mixture were characterized by various characterization methods. The characterization results indicated that $H{\beta}$/SAPO-11 composite molecular sieve exhibited a core-shell structure, with the $H{\beta}$ phase as the core and the SAPO-11 phase as the shell. The pore diameter of the composite was between that of $H{\beta}$ and SAPO-11. The composite had fewer acid sites than $H{\beta}$ and mechanical mixture while more acid sites than SAPO-11. The experimental results indicated that the composite exhibited high catalytic performances for the methylation of naphthalene with methanol.

• Korean Chemical Engineering Research
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• 제44권4호
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• pp.329-339
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• 2006

원유가 급등으로 메탄올에서 저급 올레핀을 제조하는 공정에 대한 관심이 높아지고 있다. 제올라이트와 SAPO 분자체 촉매에서 메탄올의 탄화수소로 전환 반응을 저급 올레핀 생성 단계에 중점을 두고 고찰하였다. 구조가 명확한 중간체를 근거로 하는 직접(direct) 반응기구와 구조가 애매한 탄화수소 뭉치를 활성점으로 보는 탄화수소 활성체(hydrocarbonpool) 반응기구의 합리성을, 메탄올 전환 반응의 유도기간, 생성물의 선택성, 활성 저하 등과 연계지어 비교하였다. 탄화수소 활성체의 구조 규명과 메탄올 전환 반응에서 촉매 활성점으로서 기능에 대한 1999년 이후 연구 결과를 검토하였으며, 메탄올에서 저급 올레핀을 생산하는 공정에 대한 전망도 기술하였다.

• Korean Membrane Journal
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• 제4권1호
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• pp.25-35
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• 2002

The gas permeation properties have been studied on carbon molecular sieve (CMS) membranes prepared by pyrolysis of P84 polyimide under various conditions. P84 polyimide shows high permselectivities (O$_2$/N$_2$= 9.17 and CO$_2$/N$_2$= 35) for various gas pairs and has a good processibility because it is easily soluble in high polar solvents such as N-methylpyrrolidinone (NMP), dimethylformamide (DMF), and N,N-dimethylacetamide (DMAc). After pyrolysis under Ar flow, the change in the heating rate was found to affect the gas permeation properties to some extent. The permeabilities of the selected gases were shown to be in the order He ＞ CO$_2$＞ O$_2$＞ N$_2$for all the CMS membranes, whose order was in accordance with the order of kinetic gas diameters. It also revealed that the pyrolysis temperature considerably influenced the gas permeation properties of the CMS membranes derived from P84 polyimide. The CMS membranes pyrolized at 700$\^{C}$ temperature exhibited the highest permeability with relatively targe loss in permselectivity. This means that the pyrolysis temperature should be varied in accordance with target gases to be separated.

• 한국표면공학회지
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• 제25권3호
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• pp.144-149
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• 1992

The adsorption and molecular sieve characteristics of water, methanol, ethanol, butanol and benzene on acid-alkali treated natural zeolite from Kampo area were investigated by the Diamond·Kinter method, and it was compared with synthetic zeolite A. Adsorption amount of water increased with the treatment of acid rather than the treatment of alkali. Similar tendency was observedd in adsorption of alcohols such as methanol, ethanol and butanol, but the amount of adsorption decreased. From the views of the molecular size, adsorption amount of benzene decreased because of surface activity according to the cations species rather than chemical treatment. And it was almost same value that the amount of adsorption was compared acid treated natural zeolite with synthetic zeolite A.

• 멤브레인
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• 제11권1호
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• pp.1-13
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• 2001

• 한국막학회:학술대회논문집
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• 한국막학회 2005년도 추계 총회 및 학술발표회
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• pp.39-47
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• 2005

• Bulletin of the Korean Chemical Society
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• 제21권10호
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• pp.1015-1019
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• 2000

• Bulletin of the Korean Chemical Society
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• 제19권4호
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• pp.397-399
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• 1998

• 멤브레인
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• 제7권1호
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• pp.15-21
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• 1997

Carbon molecular sieve (CMS) membranes were synthesized by the pyrolysis of polymeric precursors. The CMS materials had oxygen-nitrogen selectivities much higher than those observed for the polymeric precursors. Typically molecular sieving materials have diffusion selectivities much higher than polymeric materials. This has been identified as a result of higher entropic selectivity of the molecular sieving materials. A study of the development of molecular sieving properties as the polymeric precursor is pyrolyzed into a CMS material will offer us an insight into polymeric molecular structures needed for enhanced entropic selectivity membrane materials.