Hydrocracking of n-Hexadecane

Figure 13.36 Dimethylbutane n-hexane selectivity ratios from hydrocracking of n-hexadecane over various framework types [75].

Fig. 6.3 Molar carbon number distributions in catalytic cracking and hydrocracking of n-hexadecane at 50% conversion (24)...

Figure 5 - Products from hydrocracking of n-hexadecane with two different catalysts.

De Haan, R., Joorst, G., Mokoena, E., Nicolaides, C.P., 2007. Non-sullided nickel supported on sihcated alumina as catalyst for the hydrocracking of n-hexadecane and of iron-based Fischer—Tropsch wax. Apphed Catalysis A 327, 247—254. 

The rate of hydrocracking of n-paraflfins increases with increasing molecular weight (2, 22). For example, Flinn, Larson, and Beuther (22) observed that 95% conversion of n-hexadecane was obtained at conditions at which 53% n-octane was converted. 

The ability of water molecules to promote a reaction depends on many factors. In most cases, zeolites with monovalent cations have low activity. However, the addition of water molecules to X and Y zeolites with monovalent ions increased the isomerization of cyclopropane (63). De-cationized zeolites can be promoted readily with water, and the process is reversible (2, 60, 64). It was shown (2) that the promoting ability of water molecules in faujasites is less when the Si02/Al203 increases. Dealu-minated faujasites are even more difficult to promote. For erionite and mordenite the maximum effect of water was observed only after treatment with liquid water and subsequent heating (2). The effect of water on zeolites saturated with polyvalent cations is less pronounced (65, 66, 67). However, the presence of multivalent cations stabilizes the catalytic activity. Water and alcohols were reported to promote ion exchanged zeolites for n-pentane isomerization (68) and n-hexadecane hydrocracking (69). 

Product distributions from the hydrocracking of typical normal paraffins with nickel sulfide on silica alumina catalyst (34, 59) are shown in Figure 1 (n-hexadecane) and Table I (n-decane). Table I also includes results with silica-alumina and with nickel on silica-alumina (discussed later). 

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