Cyclohexane breakthrough

Comparing the log-scaled TBB breakthrough plots vs time for mixed M and separated S beds of activated carbon and molecular sieve without or with water vapour, it can be affirmed that separated activated carbon/molecular sieve bed ( S ) is more effective than mixed ( M ). In the case of cyclohexane breakthrough a negative effect caused by mixing of activated carbon with molecular sieve is observed. This effect is probably caused by the different linear flow rates for TBB and CHX on the breakthrough experiments. 

A decisive breakthrough to a T range above 230°C was achieved with a polycarbonate based on spitobisiudan (SBI-PC, (8)) (203) or 3,3,5-trimethyl cyclohexane (TMC-PC, (7) whereia the cyclohexane ring bears three methyl groups) (204). 

Although the suspended catalysts under boiling and refluxing conditions were active for dehydrogeno-aromatization of alkyl-substituted cyclohexanes, the levels of reaction rates were unsatisfactorily low. A breakthrough toward low catalytic activities was accomplished by our introduction of "superheated liquid-film concept" (vide infra) [30]. 

Abstract. Activated carbon Norit R 08 Extra, and molecular sieve type 4A, were investigated using dynamic (tert-butylbenzene (TBB), cyclohexane (CHX) and water vapour) adsorption methods. The TBB, CHX and water breakthrough plots for fixed activated carbon - molecular sieve beds were analyzed. It was found that the type of bed composition with mechanically mixed activated carbon with molecular sieve, or separated activated carbon and molecular sieve layers, affects the dynamic adsorption characteristics. 

Keywords activated carbons molecular sieve breakthrough dynamics tert-butylbenzene adsorption cyclohexane water breakthrough time... 

Two different adsorbents, activated carbon Norit R 0.8 Extra (Norit N.V., The Netherlands) and molecular sieve (type 4A, Merck), were used to study tert-butylbenzene, cyclohexane, and water vapour breakthrough dynamics. Structural parameters of the carbon adsorbent were calculated from benzene vapour adsorption-desorption isotherms measured gravimetrically at 293 K using a McBain-Bakr quartz microbalance, and nitrogen adsorption-desorption isotherms recorded at 77.4 K using a Micromeritics ASAP 2405N analyzer described in detail elsewhere.22,24 Activated carbon Norit has a cylindrical... 

Tert-butylbenzene (BDH Chemicals Ltd Poole, England) and cyclohexane (POCH, Poland) were used as probe organic compounds in the breakthrough experiments. 

Pulsating flow through a bed and breakthrough times. An important application for activated carbons is their use in canisters for life-supporting gas masks. In use, the airflow is not constant but pulsates with respiration. Nir et al. (2002), in their review, state that previous studies had reported that the breakthrough time (Tg) was independent of flow pattern for butyl alcohol, methyl chloroform, cyclohexane and ethyl acetate. On the contrary, evidence is presented that (Tg) could be reduced by 5-30% under conditions of sinusoidal, rectangular and square profiles. 

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