ions (+C[H.sub.2]OH) was formed in the mixture of formaldehyde solution and hydrochloric acid solution.
At high reaction temperature (>600[degrees]C), C4 hydrocarbons will certainly undergo free radical reactions, as well as carbonium ion reactions on the active centres of catalyst surface.
The cracking rate of alkenes is much higher than that of alkanes following the carbonium ion mechanism, therefore, catalytic pyrolysis of C4 hydrocarbons at low temperature mainly follows the carbonium ion mechanism.
For the cracking of hydrocarbons, the selectivity of ethene and ethane following the carbonium ion mechanism is generally lower than that following the free radical mechanism.
Due to the addition of acetic anhydride to the DMC in [H.sub.2]S[O.sub.4] (concentrated), bathochromic shift has been reorganized in terms of stability conferred on the carbonium
ion (II [right arrow] III) by acetylation with acetic anhydride (Figure 2).
They reported that the hydrolysis of the glycosidic linkages was SN1 reaction and the rate limiting is the formation of the carbonium
A sulfated 1'-hydroxy intermediate that can undergo rearrangement to form an active carbonium species is believed to be the biologically active form of methyl eugenol.
The results of these studies support the hypothesis that the formation of a carbonium ion species that can react with DNA is the critical metabolite for methyl eugenol exposure.
Relatively high doses of methyl eugenol that overwhelm the most common metabolic pathways have been suggested as the mechanism resulting in the formation of a reactive carbonium ion from the 1'-hydroxymethyl eugenol metabolite (Gardner et al.
Formation of the 1'-hydroxyl metabolite is particularly important because it is thought to form a carbonium ion that results in a reactive intermediate molecule (Burkey et al.
The dynamics of carbonium
ion chemistry is the concern of Ted Sorensen.
CP is a well-known mutagen and clastogenic agent  and produces the highly active carbonium
ion, which reacts with the electron-rich area of nucleic acids and proteins , CP is widely used as a genotoxic agent because it and its metabolites can bind DNA, causing damage that may result in chromosome breaks, micronucleus (Mn) formation, and cell death [6,7],