Optimization of efficiency in size-exclusion chromatography

Pyrolysis of n-pentane has been studied at the temperature range 653–753 K on ZSM-5 zeolite. High catalytic activity and selectivity of H-ZSM-5 zeolite was found. The yield of propane was about 80 wt. %. A mechanism of the process is proposed.

Pyrolysis of n-pentane on ZSM-5 zeolite

액화석유가스(liquefied petroleum gas, LPG)에 디메틸에테르(dimethyl ether, DME)가 첨가된 DME-LPG 혼합연료 의 탄화수소 화합물을 가스크로마토그래피(GC)를 이용하여 정성·정량분석하는 새로운 분석방법을 연구하였다. DMELPG 혼합연료는 함산소화합물(oxygen-containing compound)인 극성의 DME와 비극성물질인 LPG로 구성되어 있기 때문에 하나의 GC 컬럼에서 모든 성분을 완전히 분리하기가 어렵다. 따라서 서로 다른 성질의 화합물이나 아주 복잡 한 화합물 중 목표물질의 분석에 응용되고 있는 Deans switching 시스템을 도입하였다. 상기 시스템은 두 개의 GC 컬럼 사이에 유체의 압력 제어를 통하여 용출되는 물질의 흐름 방향을 변경시켜주는 기술로서, 이 방법을 이용하여 DME 와 LPG를 서로 다른 컬럼에서 분리하여 한번의 시료 주입으로 DME-LPG 혼합연료의 모든 탄화수소 화합물을 정성 정량분석할수 있었다. 또한 DME 합성과정에서 부산물로 생성될 수 있는 메탄올, 포름산메틸, 에틸메틸에테르 같은 미량성분까지 분석이 가능하였다.

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Determination Method of Hydrocarbon Compounds in DME-LPG Blending Fuels by Gas Chromatography with Deans Switching

The catalytic cracking of n-pentane over sodium, cerium and aluminium exchanged Y zeolites and H-ZSM-5 zeolite has been studied. A promoting action of oxygen at 693–753 K on the catalytic activity has been found to follow the order: CeY>AlNaY>NaY>H-ZSM-5. It is suggested that oxygen adsorbed on the CeY zeolite takes part in reactions with Ce3+ ions.

Influence of oxygen activation on the catalytic cracking of n-pentane on zeolites

An analytical GC method was developed which uses a single packed column consisting of three packings in series prepared with the following liquid phases: dimethyl sulfolane, propylene carbonate, and silver nitrate. This system provides satisfactory resolution of mixtures of C1−C5 hydrocarbons and dimethyl ether obtained when converting methanol to gasoline. Due to the high capacity of the column it is possible to inject larger sample amounts permitting trace analysis.

A. Cichowlas

Papers

A column packing for isothermal gas chromatographic analysis of C1−C5 paraffins and monoolefins and dimethyl ether