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Fuller nnd Hickinbottom 3235 589. The Synthesis and Reactions of Branched-chain Hydrocarbom. Part X V I I P Chlorination of 2,2,4-Trimethylpentane By (the late) A. E. FULLER and W. J. HICKINBOTTOMChlorination o€ 2,2,4-triinethylpentane in an cxcess of hydrocarbon by sonie N-alkyl-A'-chlorosulplionamides and by sulphuryl chloride initiated by benzoyl peroxide is compared with that brought about by chlorine activated by a weak source of ultraviolet light. With the exception of sulphuryl chloride, the product has the same composition whatever chlorinating agent is used. Furthermore, the reactivity of the tertiary hydrogen is unexpectedly low, being less than that of the secondary hydrogens.It is concluded that the chlorination by N-chlorosulphonamides occurs mainly through the formation of chlorine.The low reactivity of tlic tertiary position can be satisfactorily explained if it is assumed that only a fraction of 2,2,4-trimethylpentane has a con-Iorniation permitting free access of the chlorinating agent a t the tertiary position and that interconversion of the possible conformations is hindered.

The bulk structure, surface characteristics, catalytic properties, button cell performance, and stability of perovskite-type oxides with the formula Sr 1-x Ce xCo 0.2 Fe 0.8 O 3-d (x = 0.10, 0.15, and 0.20) were investigated as potential anode electro-catalysts for solid oxide fuel cells. In situ X-ray diffraction results indicated that the structural stability of the cerium-doped perovskites was enhanced with increasing cerium concentration. The catalysts with lower cerium concentration transformed from the initial cubic structure to a lower symmetry structure at high temperatures in a reducing environment. All the catalysts, however, were restored to the original cubic structure after re-oxidation. Electronic conductivity tests showed that the cerium-doped samples break down at higher temperatures, but display potential in terms of structural integrity and high conductivity at temperatures lower than 600°C. The new materials showed better performance than Ni-YSZ in catalytic methane oxidation tests. The sulfur tolerance is significantly enhanced with the cerium-doped perovskites, showing no deactivation for up to 10 h of operation under 50 ppm H 2 S. X-ray photoelectron spectroscopy analysis on the poisoned samples suggests that the sulfur may exist on the surface primarily as strontium sulfate. The sample with a cerium loading of 15 % (x = 0.15) showed a particularly high sulfur tolerance during chronoamperometry tests and its button cell performance matched well with that of Ni-YSZ anode. Sr 1-x Ce x Co 0.2 Fe 0.8 O 3-d (x = 0.10, 0.15, and 0.20) samples may have potential for low or intermediate temperature SOFC operation in which sulfur-containing hydrocarbon fuels are used, although they would not be stable at higher temperatures.