Author :
Dabbagh, Hossein A.,Tau, Li-Min,Halasz, Janos
Abstract :
1-and 2-propanol incorporate into the products of the Fischer-Tropsch synthesis,about 10-20,of the added 1-propanol was incorporated but only 1-3,of the 2-propanol was incorporated. The carbon skeleton that is added as alcohol remains intact during the incorporation,furthermore,the constant activity/mole in the products with carbon numbers greater than that of the alcohol indicates that this carbon fragment initiates chain growth. The n-alcohol initiates growth to produce i/n ratios that are lower than those produced from the syngas synthesis, and the n-hydrocarbons have a higher activity than the corresponding iso-hydrocarbons:the i/n ratio and labeling of i- and n-products are just, the opposite for 2-propanol. 1- and 2-pronanol produce surface species that remain distinct and initiate different synthesis reaction pathways. Thus, n-alcohol initation leads to predominately n-hydrocarbons whereas the iso-alcohol initiates chain growth that leads predominately to iso-hydrocarbons. Dehydrogenation to aldehyde or ketone occurred with both alcohols to produce the thermodynamic equilibrium composition anticipated for the particular alcohol. In addition, a significant fraction of the alcohol undergoes hydrogenolysis to the corresponding alkane.For the n-alcohol,but not the iso-alcohol,loss of the carbinol carbon to produce CO2 occurs by a direct pathway that does not involve Co as an intermediate.
